Disclosure of Invention
The invention aims to provide a seawater desalination impurity pretreatment system and a seawater desalination impurity pretreatment process, aiming at solving the problems that the existing seawater desalination impurity pretreatment process lacks of targeted regulation and control on temperature influence, does not establish a dynamic feedback regulation mechanism based on flocculation sedimentation effect, and is easy to cause overload of a subsequent treatment unit.
The invention is realized in the following way:
According to a first aspect of the invention, the invention provides a seawater desalination impurity pretreatment process, which comprises rough filtration, flocculation sedimentation, filter filtration and ultrafiltration, wherein the flocculation sedimentation comprises the following specific steps:
s100, detecting the temperature of the seawater after rough filtration, when the temperature of the seawater is lower than a set temperature interval which is favorable for flocculation reaction, heating the seawater after rough filtration by using waste heat recovered by evaporating the seawater, and stabilizing the temperature of the seawater in the temperature interval which is favorable for flocculation reaction when the energy of the waste heat is enough;
S200, conveying the heated seawater to a mixing tank, detecting the temperature of the heated seawater, adding a flocculating agent according to the dosage corresponding to the temperature, and mixing the flocculating agent with the seawater;
S300, conveying the seawater mixed with the flocculant to a flocculation reaction tank for flocculation reaction;
s400, conveying the seawater after flocculation reaction to a flocculation sedimentation tank, measuring concentration data of different depths of the flocculation sedimentation tank, and correcting the adding amount of a flocculating agent, the flow rate of the seawater into the flocculation sedimentation tank, the stirring intensity of a mixing tank, the residence time of the seawater in the flocculation reaction tank and the stirring intensity in the flocculation reaction tank according to each measurement data.
Further, along the sea water flow direction, quick mixing zone and slow flocculation zone have been set gradually in the flocculation reaction tank, all be provided with agitating unit in quick mixing zone and the slow flocculation zone, the stirring intensity in the flocculation reaction tank includes the stirring intensity in quick mixing zone and the stirring intensity in slow flocculation zone.
Further, in the step S400, concentration sensors are disposed at different depths of the flocculation sedimentation tank, including an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor, wherein the upper water concentration sensor is disposed at a position 0.5-1 m below the water surface, and the middle water concentration sensor is disposed at a distance from the bottom of the flocculation sedimentation tankWithin the range of (1), in whichIs the depth of the concentration tank, andThe lower water concentration sensor is arranged in the range of 0.3-0.8 meter away from the bottom of the pool.
Further, the measurement data of the upper water concentration sensor, the middle water concentration sensor and the lower water concentration sensor are C1、C2 and C3 respectively, the corresponding preset concentration thresholds of the upper water concentration sensor, the middle water concentration sensor and the lower water concentration sensor are T1、T2 and T3 respectively, and T1＜T2＜T3 is adopted;
if C1＜T1 and C2＜T2, no correction is performed;
if C3 is more than or equal to T3, immediately starting a mud discharging device at the bottom of the flocculation sedimentation tank;
If C1＜T1 and C2≥T2, reducing the stirring intensity of the slow flocculation area, and simultaneously optionally executing one or more of the following adjustment operations, namely, improving the stirring intensity of the mixing tank, improving the stirring intensity of the fast mixing area in the flocculation reaction tank, improving the adding amount of the flocculant, reducing the flow rate of the seawater entering the flocculation sedimentation tank and prolonging the residence time of the seawater in the flocculation reaction tank;
If the ratio is C1≥T1 and C2＜T2, the stirring intensity of the mixing tank and the stirring intensity of a rapid mixing area in the flocculation reaction tank are improved, and one or more of the following adjusting operations can be simultaneously selected to be executed, namely, the adding amount of the flocculating agent is improved, the flow rate of the seawater entering the flocculation sedimentation tank is reduced, and the residence time of the seawater in the flocculation reaction tank is prolonged;
If C1≥T1 and C2≥T2:
When C3＜T3 is carried out, the stirring intensity of the mixing tank is improved, the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the adding amount of a flocculating agent is improved, the stirring intensity of a slow flocculation area is reduced, and one or more of the following adjusting operations can be simultaneously selected and executed, namely, the flow rate of seawater entering a flocculation sedimentation tank is reduced, and the residence time of the seawater in the flocculation reaction tank is prolonged;
When C3≥T3, the stirring intensity of the mixing tank is improved, the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the adding amount of a flocculating agent is improved, the stirring intensity of a slow flocculation area is reduced, the flow velocity of seawater entering the flocculation sedimentation tank is reduced, the residence time of the seawater in the flocculation reaction tank is prolonged, meanwhile, a mud discharging device at the bottom of the flocculation sedimentation tank is immediately started, and the mud discharging speed is improved.
Further, based on the combination of different concentration data, the specific quantitative correction mode of each process parameter is as follows:
if C1＜T1 and C2≥T2:
when the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 10% -15%;
when the stirring intensity of the mixing tank is improved, the stirring speed is improved by 10% -15%;
when the stirring intensity of a rapid mixing area in a flocculation reaction tank is improved, the stirring speed is improved by 10-15%, and when the adding amount of a flocculating agent is improved, the adding amount is increased from that ofIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5;
when the flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 80% -90% of the original flow rate;
when the residence time of the seawater in the flocculation reaction tank is prolonged, the inflow water flow is reduced by 10% -20%;
If C1≥T1 and C2＜T2:
When the stirring intensity of the mixing tank is improved, the stirring speed is improved by 15% -25%;
when the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5;
when the flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 80% -90% of the original flow rate;
when the residence time of the seawater in the flocculation reaction tank is prolonged, the inflow water flow is reduced by 10% -20%;
If C1≥T1、C2≥T2 and C3＜T3:
when the stirring intensity of the mixing tank is improved, the stirring speed is improved by 20% -30%;
when the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the stirring speed is improved by 20% -25%;
when the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 15% -25%;
when the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: Where k is the adjustment coefficient, whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5 percent of the raw materials, wherein,,;
When the flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 70% -80% of the original flow rate;
The retention time of the seawater in the flocculation reaction tank is prolonged, and the inflow rate is reduced by 15% -25%;
if C1≥T1、C2≥T2 and C3≥T3:
when the stirring intensity of the mixing tank is improved, the stirring speed is improved by 30% -35%;
When the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the stirring speed is improved by 25% -30%;
when the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 15-25%, and when the adding amount of the flocculant is increased, the adding amount is reduced from that of the low-speed flocculation areaIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.2 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.3-0.4 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.5-0.6, wherein,,,;
When the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 20% -30%;
when the flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 60% -70% of the original flow rate;
when the residence time of the seawater in the flocculation reaction tank is prolonged, the inflow water flow is reduced by 20% -30%;
When the mud discharging device at the bottom of the flocculation sedimentation tank is started, the rotating speed of the mud discharging pump is increased by 50%, and meanwhile, the operating frequency of the motor of the mud scraper is increased.
Further, the temperature range favorable for flocculation reaction is 27-32 ℃, a hollow fiber ultrafiltration membrane is adopted in the ultrafiltration step, the pore diameter of the membrane is 0.01-0.1 mu m, the operating pressure is 0.1-0.3MPa, air-water back flushing is carried out every 30-60 minutes in the ultrafiltration process, the back flushing time is 3-5 minutes, when the membrane flux is reduced to 70-80% of the initial value, a chemical cleaning program is started, and a citric acid solution with the mass fraction of 2-3% or a sodium hydroxide solution with the mass fraction of 0.5-1% is adopted for circular cleaning, and the cleaning time is 60-90 minutes.
According to a second aspect of the invention, the invention provides a seawater desalination impurity pretreatment system, which comprises a coarse filtration module, a flocculation sedimentation module, a filter module, an ultrafiltration module, a control system module, a pipeline and a valve system module, wherein the flocculation sedimentation module comprises a seawater temperature detection unit, a heating unit, a mixing tank unit, a flocculation reaction tank unit and a flocculation sedimentation tank unit, the seawater temperature detection unit comprises a water inlet temperature detection sensor and a water outlet temperature detection sensor, the heating unit is used for heating seawater discharged by the coarse filtration module, the water inlet temperature detection sensor is used for detecting the temperature of the seawater discharged by the coarse filtration module, the water outlet temperature detection sensor is used for detecting the temperature of the seawater heated by the heating unit, the mixing tank unit comprises a mixing tank and a flocculant adding system, a stirring device is arranged in the mixing tank, the flocculant adding system is used for adding a flocculant into the mixing tank, the flocculation reaction tank unit comprises a rapid mixing zone and a slow flocculation zone which are sequentially arranged along the flowing direction of the seawater, a flow guide plate is arranged between the rapid mixing zone and the slow flocculation zone, the rapid mixing zone and the slow flocculation zone are arranged, the rapid mixing zone and the slow flocculation zone are used for detecting the temperature sensor is used for detecting the temperature of the seawater temperature, the seawater temperature detection sensor is used for detecting the temperature of the seawater discharged by the coarse filtration module, the water temperature detection sensor is used for detecting the temperature of the heated by the heating module, the water inlet temperature sensor is used for detecting the heated by the heating module, the water temperature after the heating module is used for heating, the heating module is used for heating the seawater temperature, the temperature after heating, the heating module is used for heating, the heating module, the temperature is used for heating, the temperature, the heating module is used for heating, the temperature module is used for heating, the heating module and the flocculant, the flocculant is used for adding the device and the device comprises.
Further, the concentration sensor in the flocculation sedimentation tank comprises an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor, wherein the upper water concentration sensor is arranged at a position 0.5-1 m below the water surface, and the middle water concentration sensor is arranged at a position away from the bottom of the tankWithin the range of (1), in whichIs the depth of the concentration tank, andThe lower water concentration sensor is arranged in the range of 0.3-0.8 meter away from the bottom of the pool.
The flocculation sedimentation device comprises a flocculation sedimentation tank unit, a pipeline and a valve system module, wherein the pipeline and the valve system module are used for connecting a rough filtration module, a flocculation sedimentation module, a filter module and an ultrafiltration module to form a complete seawater conveying path, an electric control regulating valve is arranged on a connecting pipeline between the rough filtration module and the flocculation sedimentation module and used for regulating and controlling the flow rate of seawater entering the flocculation sedimentation tank under the control of the control system module, and an electric control regulating valve is arranged on a pipeline between the flocculation reaction tank unit and the flocculation sedimentation tank unit and used for regulating the flow rate of the seawater entering the flocculation sedimentation tank under the control of the control system module.
Further, the filter module comprises a multi-medium filter and a cartridge filter, the multi-medium filter comprises a tank body, a lifting assembly and a water pump, a dirt sucking pipe and an ultrasonic generator are arranged on the tank body, the water sucking end of the water pump is connected with the dirt sucking pipe, the lifting assembly is arranged on the tank body, the output end of the lifting assembly is inserted into the tank body, the dirt sucking pipe is connected with a directional straw in an inserting mode, the directional straw is connected with the output end of the lifting assembly, the lifting assembly is used for driving the directional straw to move up and down, a multi-medium filter element is arranged in the tank body, a plurality of multi-medium filter elements are arranged in the tank body, guide plates are arranged between the top end and the bottom end of the multi-medium filter element and two adjacent filter media, guide holes are uniformly formed in the guide plates, the hole sizes of the guide holes in each guide plate are different, and the guide hole sizes of the guide plates are gradually reduced from top to bottom.
Compared with the prior art, the seawater desalination impurity pretreatment process has the beneficial effects that aiming at the remarkable influence of the seawater temperature on flocculation reaction, the seawater after rough filtration is heated by utilizing the evaporation waste heat of the seawater desalination, so that the seawater temperature entering a flocculation sedimentation process is stabilized in or closer to a temperature range favorable for flocculation reaction, the hydrolysis efficiency and activity of a flocculant are effectively improved, and the use effect of the flocculant is further improved. Meanwhile, the addition amount of the flocculant is accurately matched in combination with the real-time water temperature, so that the problem of medicament waste or deficiency caused by temperature fluctuation is avoided. In addition, by setting concentration sensors at different depths of the flocculation sedimentation tank, a layered monitoring system for different depths of the flocculation sedimentation tank is constructed, a dynamic feedback regulation mechanism based on the seawater concentration of different depths of the flocculation sedimentation tank is established, when detection data show that the flocculation sedimentation effect deviates from expectations, key parameters such as the addition amount of a flocculating agent, the flow rate of seawater entering the flocculation sedimentation tank, the stirring intensity of each reaction area, the residence time of the seawater and the like are automatically optimized and corrected, the stability and the high efficiency of the flocculation sedimentation effect are effectively ensured, water inlet conditions with stable water quality and low impurity content can be provided for the subsequent treatment process, and the load of the subsequent treatment process is effectively reduced. Additional advantages of the invention are set forth in the description which follows.
Detailed Description
In the present invention, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, mechanically connected, electrically connected, directly connected, or indirectly connected via an intermediary. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The following is further described with reference to the accompanying drawings and specific examples:
Example 1
As shown in fig. 1 and 2, the present embodiment provides a seawater desalination impurity pretreatment process including rough filtration, flocculation sedimentation, filter filtration and ultrafiltration, the filter filtration including multi-media filter filtration and cartridge filter filtration. The two-stage rough filtration system which combines a grating filter and a self-cleaning filter is used for rough filtration, a mechanical grating is arranged at the front end of the seawater entering the pretreatment system, the grating distance is 5-10mm, and large-scale floaters in the seawater, such as seaweed, shells, plastic fragments and the like, are mainly intercepted, so that blocking caused by entering subsequent equipment is avoided. The seawater filtered by the grid enters a self-cleaning filter with the filtering precision of 50-100 mu m, and small particle impurities such as fine sand, plankton debris and the like are trapped by a stainless steel filter screen or a wedge-shaped filter screen. The flocculation sedimentation specifically comprises the following steps:
S100, detecting the temperature of the seawater after rough filtration, and when the temperature of the seawater after rough filtration reaches a set temperature interval which is beneficial to flocculation reaction, heating is not needed. When the temperature of the seawater is lower than a set temperature range which is favorable for flocculation reaction, the waste heat recovered by evaporating the seawater is used for heating the seawater after rough filtration. The temperature range favorable for flocculation reaction is 27-32 ℃, the temperature is too low, the thermal movement of water molecules is weakened, the hydrolysis speed of the flocculant is slow, the formed floccules are fine and loose, the sedimentation performance is poor, the effect can be ensured only by increasing the adding amount, the hydrolysis of the flocculant can be accelerated when the temperature is within the range of 27-32 ℃, the collision and condensation of colloid particles are promoted, the formation speed of the floccules is fast, the structure is compact, and the sedimentation efficiency can be effectively improved. Meanwhile, the temperature is not easy to be too high, the stability of the flocculant is reduced when the temperature is too high, or the floccule structure is damaged too severely due to the movement of water molecules, so that the effect is reduced. When the waste heat energy is enough, the temperature of the seawater is stabilized in a temperature range which is favorable for flocculation reaction, and when the temperature of the seawater after rough filtration is lower and the recovered waste heat is insufficient for heating the seawater to the temperature range which is favorable for flocculation reaction, two treatment schemes exist, namely, an additional heating structure is arranged for heating, and an additional heating structure is not arranged for heating, so that the seawater can be selected according to the condition of the seawater quality in the current sea area and the comprehensive cost.
And S200, conveying the heated seawater to a mixing tank, detecting the temperature of the heated seawater, adding a flocculating agent according to the dosage corresponding to the temperature, and mixing the flocculating agent with the seawater. Accurate flocculant adding according to the specific temperature of seawater is based on the obvious influence of temperature on the activity of the flocculant, namely, the hydrolysis rate, molecular diffusion capacity and the combination efficiency of the flocculant and colloidal particles are different at different temperatures, and if the flocculant is added according to fixed doses, the problems of insufficient medicament at low temperature and medicament waste at high temperature are easy to occur. In order to realize accurate control, a temperature-dose comparison table is built in the seawater desalination impurity pretreatment system, the table is formed by fitting a large amount of early experimental data, and the optimal flocculant addition amounts corresponding to different temperature intervals are clearly marked.
S300, conveying the seawater mixed with the flocculant to a flocculation reaction tank for flocculation reaction. Along the sea water flow direction, set gradually quick mixing district and slow flocculation district in the flocculation reaction tank, all be provided with agitating unit in quick mixing district and the slow flocculation district, the stirring intensity in the flocculation reaction tank includes the stirring intensity in quick mixing district and the stirring intensity in the slow flocculation district.
S400, conveying the seawater after flocculation reaction to a flocculation sedimentation tank for flocculation sedimentation, and simultaneously measuring concentration data of different depths of the flocculation sedimentation tank. Specifically, concentration sensors are arranged at different depths of the flocculation sedimentation tank and comprise an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor, wherein the upper water concentration sensor is arranged at a position 0.5-1 m below the water surface, and the middle water concentration sensor is arranged at a distance from the bottom of the flocculation sedimentation tankWithin the range of (1), in whichIs the depth of the concentration tank, andThe lower water concentration sensor is arranged in the range of 0.3-0.8 meter away from the bottom of the pool.
S500, correcting one or more of the addition amount of the flocculating agent, the flow rate of the seawater entering the flocculation sedimentation tank, the stirring intensity of the mixing tank, the residence time of the seawater in the flocculation reaction tank and the stirring intensity in the flocculation reaction tank according to each measurement data and a preset rule. The measurement data of the upper water concentration sensor, the middle water concentration sensor and the lower water concentration sensor are C1、C2 and C3 respectively, and the corresponding preset concentration thresholds of the upper water concentration sensor, the middle water concentration sensor and the lower water concentration sensor are an upper water concentration threshold T1, a middle water concentration threshold T2 and a lower water concentration threshold T3 respectively. The upper water should be as clear as possible with the lowest impurity concentration to reduce the load for subsequent filtration, so T1 is set to the lowest threshold. The middle water is between the supernatant and the lower sludge, allowing for a concentration of fine flocs or incompletely settled impurities, but below the lower layer, so T2 needs to be above T1. Most of settled flocs and sludge are accumulated in the lower water, the concentration is highest, but the concentration is controlled in a reasonable range, and the phenomenon that the sludge is excessively accumulated to cause back mixing and influence the quality of supernatant is avoided, so that T3 is set to be the highest threshold value and is required to be higher than T2. Therefore, T1＜T2 ＜T3. The upper water concentration threshold T1, the middle water concentration threshold T2 and the lower water concentration threshold T3 are set based on the principle of flocculation sedimentation process and the target treatment effect, and are fitted by a large amount of early experimental data.
When correction is performed according to each measurement data and a preset rule, the specific correction rule is as follows:
If C1＜T1 and C2＜T2, no correction is performed.
If C3≥T3, immediately starting the mud discharging device at the bottom of the flocculation sedimentation tank.
If C1＜T1 and C2≥T2 are carried out, the impurity concentration in the upper water body of the flocculation sedimentation tank is lower than a preset threshold value, which indicates that the upper water body forms a relatively clear water body, and the overall flocculation reaction does not have global failure. The impurity concentration of the middle layer water body exceeds the standard, which means that the middle layer flocs are not fully formed or loose in structure, so that the formed flocs are sheared and crushed, cannot effectively settle to the lower layer, and are suspended in the middle layer. The core contradiction of the layering phenomenon is that the stirring intensity of a slow flocculation area is not matched, namely the core function of slow flocculation is to gradually collide and combine small flocs into large and compact flocs through low-intensity stirring, and if the stirring is too strong, the polymerization process of the flocs can be destroyed, so that the middle-layer flocs cannot be effectively settled. Therefore, reducing the stirring intensity in the slow flocculation zone is a "symptomatic measure" that directly solves the exceeding of the middle layer concentration, and must be performed preferentially.
Therefore, the stirring intensity of the slow flocculation area needs to be reduced, the stirring speed is reduced by 10-15%, and in order to assist in optimizing the preamble link of the flocculation reaction, one or more of the following adjustment operations can be simultaneously selected to be executed:
The stirring intensity of the mixing pool is improved, and the stirring speed is improved by 10% -15%, so that the initial mixing effect of the flocculant and the seawater is enhanced, and the uniform dispersion of the medicament is ensured.
The stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the stirring speed is improved by 10% -15%, and the initial mixing effect of the flocculant and the seawater is enhanced.
When the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5.
The flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 80% -90% of the original flow rate, and the flocculation sedimentation is promoted by increasing the standing or reaction time of the water body.
The residence time of the seawater in the flocculation reaction tank is prolonged by reducing the inflow rate by 10-20%, and the flocculation sedimentation is promoted by increasing the standing or reaction time of the water body.
If C1≥T1 and C2＜T2, this phenomenon is less common, but if it occurs, it indicates that the defect of the initial mixing link occurs, but the special working condition that the subsequent flocculation growth link is effective. The mixing pool and the rapid mixing area are the core links of medicament dispersion, colloid destabilization and micro-floc formation, and need to be reinforced simultaneously. Therefore, the stirring intensity of the mixing tank and the stirring intensity of the rapid mixing area in the flocculation reaction tank are improved, the stirring speed is improved by 15-25% when the stirring intensity of the mixing tank is improved, and the stirring speed is improved by 15-20% when the stirring intensity of the rapid mixing area in the flocculation reaction tank is improved. And may simultaneously choose to perform one or more of the following adjustment operations:
when the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5.
The flow rate of seawater entering the flocculation sedimentation tank is reduced, and the flow rate is reduced to 80% -90% of the original flow rate.
The residence time of the seawater in the flocculation reaction tank is prolonged, and the inflow rate is reduced by 10-20%.
If C1≥T1、C2≥T2 and C3＜T3 show that the initial medicament dispersion and colloid destabilization of the mixing tank and the rapid mixing area are insufficient, the process of polymerizing micro flocs into large flocs in the slow flocculation area is blocked, but the final sedimentation link of separating large flocs has normal functions (once enough large flocs are formed, the sedimentation can be effectively carried out and the sedimentation is not disturbed). In short, the front end mixing is not done, the middle flocculation is not kept up, but as long as the flocculation can grow, the end sedimentation is not greatly affected. At this time, it is necessary to increase the stirring intensity of the mixing tank, increase the stirring intensity of the rapid mixing zone in the flocculation reaction tank, increase the amount of flocculant added, and decrease the stirring intensity of the slow flocculation zone. When the stirring intensity of the mixing tank is improved, the stirring speed is improved by 20% -30%. When the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the stirring speed is improved by 20% -25%. When the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 15-25%. When the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: Where k is the adjustment coefficient, whenIn the time-course of which the first and second contact surfaces,Taking 0.05-0.1 part, and whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.15 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.4-0.5 percent of the raw materials, wherein,,。
In addition, one or more of the following adjustment operations may also be optionally performed simultaneously:
The flow rate of seawater entering the flocculation sedimentation tank is reduced, and the flow rate is reduced to 70-80% of the original flow rate.
The residence time of the seawater in the flocculation reaction tank is prolonged, and the inflow rate is reduced by 15-25%.
If C1≥T1、C2≥T2 and C3≥T3, the whole process of the mixed-flocculation-sedimentation process in the specification fails, and a systematic emergency intervention is required to be started, and the core of the processing logic is to synchronously repair the defects of each link and prevent the system from collapsing. At the moment, the stirring intensity of the mixing tank is improved, the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the adding amount of a flocculating agent is improved, the stirring intensity of a slow flocculation area is reduced, the flow velocity of seawater entering the flocculation sedimentation tank is reduced, the residence time of the seawater in the flocculation reaction tank is prolonged, meanwhile, a mud discharging device at the bottom of the flocculation sedimentation tank is immediately started, and the mud discharging speed is improved. When the stirring intensity of the mixing tank is improved, the stirring speed is improved by 30% -35%. When the stirring intensity of a rapid mixing area in the flocculation reaction tank is improved, the stirring speed is improved by 25% -30%. When the adding amount of the flocculant is increased, the adding amount is changed fromIs adjusted toWhereinFor the current dosage of the flocculant,In order to adjust the adding amount of the flocculant,AndThe formula is satisfied: WhereinTo adjust the coefficient whenIn the time-course of which the first and second contact surfaces,Taking 0.1-0.2 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.2-0.3 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.3-0.4 part as the raw materialIn the time-course of which the first and second contact surfaces,Taking 0.5-0.6, wherein,,,. When the stirring intensity of the slow flocculation area is reduced, the stirring speed is reduced by 20-30%. When the flow rate of seawater entering the flocculation sedimentation tank is reduced, the flow rate is reduced to 60-70% of the original flow rate. When the residence time of the seawater in the flocculation reaction tank is prolonged, the inflow water flow is reduced by 20-30%. When the mud discharging device at the bottom of the flocculation sedimentation tank is started, the rotating speed of the mud discharging pump is increased by 50%, and meanwhile, the running frequency of the motor of the mud scraper is increased by 10% -15%.
The filter filtration comprises multi-medium filter filtration and cartridge filter filtration, wherein the medium filter and the cartridge filter are respectively used as the last barrier before ultrafiltration, and PP cotton or a folding filter element with the precision of 5-20 mu m is adopted to intercept micro particles which are not removed by the prior art and prevent the micro particles from entering an ultrafiltration membrane to cause scratch or blockage.
The ultrafiltration step adopts a hollow fiber ultrafiltration membrane, the pore diameter of the membrane is 0.01-0.1 mu m, the operating pressure is 0.1-0.3MPa, air-water back flushing is carried out every 30-60 minutes in the ultrafiltration process, the back flushing time is 3-5 minutes, when the membrane flux is reduced to 70-80% of the initial value, a chemical cleaning procedure is started, and a citric acid solution with the mass fraction of 2-3% or a sodium hydroxide solution with the mass fraction of 0.5-1% is adopted for circular cleaning, wherein the cleaning time is 60-90 minutes.
In summary, according to the seawater desalination impurity pretreatment process provided by the invention, aiming at the remarkable influence of the seawater temperature on flocculation reaction, the evaporation waste heat of seawater desalination is utilized to heat the roughly filtered seawater, so that the seawater temperature entering a flocculation sedimentation process is stabilized in or closer to a temperature range favorable for flocculation reaction, thus effectively improving the hydrolysis efficiency and activity of the flocculant, and further improving the use effect of the flocculant. Meanwhile, the addition amount of the flocculant is accurately matched in combination with the real-time water temperature, so that the problem of medicament waste or deficiency caused by temperature fluctuation is avoided. In addition, by setting concentration sensors at different depths of the flocculation sedimentation tank, a layered monitoring system for different depths of the flocculation sedimentation tank is constructed, a dynamic feedback regulation mechanism based on the seawater concentration of different depths of the flocculation sedimentation tank is established, when detection data show that the flocculation sedimentation effect deviates from expectations, key parameters such as the addition amount of a flocculating agent, the flow rate of seawater entering the flocculation sedimentation tank, the stirring intensity of each reaction area, the residence time of the seawater and the like are automatically optimized and corrected, the stability and the high efficiency of the flocculation sedimentation effect are effectively ensured, water inlet conditions with stable water quality and low impurity content can be provided for the subsequent treatment process, and the load of the subsequent treatment process is effectively reduced.
Example 2
As shown in fig. 3, the present embodiment provides a seawater desalination impurity pretreatment system for implementing the seawater desalination impurity pretreatment process provided in embodiment 1. The seawater desalination impurity pretreatment system comprises a coarse filtration module, a flocculation sedimentation module, a filter module, an ultrafiltration module, a control system module and a pipeline and valve system module. The coarse filtration module comprises a grating filter and a self-cleaning filter, wherein a mechanical grating is arranged at the front end of the seawater entering the pretreatment system, the grating distance is 5-10mm, and large-scale floaters in the seawater, such as seaweed, shells, plastic fragments and the like, are mainly intercepted, so that blocking caused by entering subsequent equipment is avoided. The seawater filtered by the grid enters a self-cleaning filter with the filtering precision of 50-100 mu m, and small particle impurities such as fine sand, plankton debris and the like are trapped by a stainless steel filter screen or a wedge-shaped filter screen. Meanwhile, the self-cleaning filter has a timing or constant pressure difference automatic cleaning function, when the pressure difference reaches a set value due to excessive interception of impurities by the filter screen or the running time reaches a preset cleaning period, a back flushing program can be automatically started, the intercepted impurities are flushed and discharged through reverse water flow, and the filtering efficiency and the continuity are ensured.
The filter module comprises a multi-medium filter and a cartridge filter, the cartridge filter is used as a subsequent guarantee of the multi-medium filter, and a filter element with higher precision is adopted, so that fine particles leaked by the multi-medium filter can be effectively trapped, and the fine particles can be prevented from entering the ultrafiltration module to damage the ultrafiltration membrane. The ultrafiltration module comprises an ultrafiltration membrane component, the ultrafiltration membrane component adopts an ultrafiltration membrane with proper molecular weight cut-off, and the membrane material has good chemical stability and mechanical strength, and can carry out deep filtration on the seawater treated by the preamble. The working principle is based on the screening action of the membrane, when seawater flows through the surface of the ultrafiltration membrane under the drive of pressure, impurities such as fine colloid, microorganism, macromolecular organic matters and the like are trapped because the impurities cannot permeate through the membrane holes, and filtrate with better water quality is permeated through the membrane, so that the purity of the seawater is further improved, and high-quality inflow water is provided for the subsequent reverse osmosis technology of seawater desalination and the like. The ultrafiltration module can carry out deep filtration on the seawater subjected to the pretreatment, entraps impurities such as fine colloid and microorganism, and further improves the water quality.
The flocculation sedimentation module comprises a seawater temperature detection unit, a heating unit, a mixing tank unit, a flocculation reaction tank unit and a flocculation sedimentation tank unit, wherein the seawater temperature detection unit comprises a water inlet temperature detection sensor and a water outlet temperature detection sensor, and the sensors adopt a thermistor or thermocouple principle and can accurately detect the seawater temperature in real time. The water inlet temperature detection sensor is arranged on a pipeline between the water outlet of the coarse filtration module and the water inlet of the heating unit and used for detecting the temperature of the seawater discharged by the coarse filtration module, and the water outlet temperature detection sensor is arranged on the water outlet pipeline of the heating unit and used for detecting the temperature of the seawater heated by the heating unit and providing accurate temperature data for the control system module to regulate and control the heating unit.
The heating unit is used for heating seawater discharged by the coarse filtration module, and comprises a plurality of plate heat exchangers, and a control system module is used for regulating and controlling the temperature of hot water and the heat exchange area according to the seawater temperature data fed back by the water inlet temperature detection sensor and a preset temperature interval favorable for flocculation reaction, so that the seawater is heated to a proper temperature, and a good temperature condition is created for the subsequent flocculation reaction. The mixing tank module comprises a mixing tank and a flocculating agent adding system, wherein a stirring device is arranged in the mixing tank, and the flocculating agent adding system is provided with a precise metering pump, a flocculating agent storage tank and the stirring device and is used for adding flocculating agent into the mixing tank. The flocculation reaction tank unit comprises a rapid mixing area and a slow flocculation area which are sequentially arranged along the water flowing direction of the sea, and stirring devices are arranged in the rapid mixing area and the slow flocculation area. A guide plate is arranged between the rapid mixing area and the slow flocculation area, the guide plate adopts a fold-line-shaped structural design, the fold angle range of the guide plate is 120-150 degrees, the water flow direction can be effectively changed to form turbulence so as to promote the chemical agent and the seawater to be fully mixed, the flocculation is prevented from being broken due to severe collision, and meanwhile, the rapid mixing area is ensured to be stably transited to the slow flocculation area. The flocculation sedimentation tank unit comprises a flocculation sedimentation tank, wherein a plurality of concentration sensors are arranged in the flocculation sedimentation tank, the flocculation sedimentation tank comprises an upper water concentration sensor, a middle water concentration sensor and a lower water concentration sensor, the upper water concentration sensor is arranged at a position 0.5-1 m below the water surface, and the middle water concentration sensor is arranged at a distance from the bottom of the tankWithin the range of (1), in whichIs the depth of the concentration tank, andThe lower water concentration sensor is arranged in the range of 0.3-0.8 meter from the bottom of the pool. In addition, the flocculation sedimentation tank is also provided with a mud scraping and discharging system comprising a mud discharging pump, a mud discharging pipeline, a mud discharging valve and a mud scraper, wherein a variable frequency motor is used for driving the mud discharging pump and the mud scraper.
As shown in fig. 3, the control system module is electrically connected with the coarse filtration module, the flocculation sedimentation module, the filter module, the ultrafiltration module, the pipeline and the valve system module, and uses a PLC controller or a microprocessor as a control core to collect data transmitted by each module in real time, and perform corresponding regulation and control based on a preset algorithm and a threshold value judgment, so as to realize full-flow closed-loop control such as temperature adaptation, accurate addition of a flocculating agent, dynamic adjustment of stirring intensity, optimization correction of layering concentration feedback and the like in the seawater desalination impurity pretreatment process provided in embodiment 1, and ensure efficient impurity removal and stable operation of a subsequent treatment unit.
As shown in fig. 3, the pipeline and valve system modules are used for connecting the coarse filtration module, the flocculation sedimentation module, the filter module and the ultrafiltration module to form a complete seawater conveying path. The pipeline and valve system module is provided with an electric control regulating valve on a connecting pipeline between the coarse filtration module and the flocculation sedimentation module, and the electric control regulating valve is used for regulating and controlling the flow of seawater entering the flocculation sedimentation module under the control of the control system module. An electric control regulating valve is arranged on a pipeline between the flocculation reaction tank unit and the flocculation sedimentation tank unit and is used for regulating the flow rate of seawater entering the flocculation sedimentation tank under the control of a control system module. The electric control regulating valve can use an electric regulating ball valve or a butterfly valve, is provided with a high-precision electric actuating mechanism, and can precisely regulate and control the opening under the control of the control system module.
As shown in fig. 4,5, 9 and 15, the multi-medium filter comprises a tank 01, a lifting assembly 4, a water pump 5, a directional suction pipe 7 and a multi-medium filter element 8, wherein the tank 01 comprises a lower splicing part 1, a middle splicing part 2 and an upper splicing part 3, the lower splicing part 1, the middle splicing part 2 and the upper splicing part 3 are sequentially spliced and connected from bottom to top, and the tank 01 with the structure is convenient to assemble and convenient to overhaul or replace each part inside the tank 01. The middle part of the top end of the upper splicing part 3 is provided with a dirt sucking pipe 38, the dirt sucking pipe 38 is convenient to be matched with the water pump 5 for use, and when the water pump 5 is matched with the directional suction pipe 7 for generating suction force on the multi-medium filter element 8 during back flushing, so that dirt inside the multi-medium filter element 8 can be sucked clean better. The edge of the upper splicing part 3 is provided with an ultrasonic generator 31, the ultrasonic generator 31 is convenient for transmitting ultrasonic waves to the multi-medium filter element 8 when back flushing is carried out, when the ultrasonic waves are transmitted downwards from the top end, the transmission direction is perpendicular to the stacking direction of the filter medium layers (quartz sand, anthracite and the like), the ultrasonic waves can directly penetrate through the multi-layer medium gap, and water flow upwards flows from the bottom during back flushing and is coupled with the downward ultrasonic waves from the top end in opposite directions. The synergistic effect of the upward water flow and the downward ultrasonic can effectively strip the pollutants attached to the surface of the medium, and the ultrasonic direction of the side installation is perpendicular to the water flow direction, so that the efficient energy superposition effect is difficult to form.
The lifting component 4 is installed at the top end of the upper splicing part 3, and the output end of the lifting component 4 is inserted into the tank 01. The water suction end of the water pump 5 is connected with the sewage suction pipe 38, the bottom end of the water pump 5 is connected with the upper splicing part 3, the directional suction pipe 7 is connected with the sewage suction pipe 38 in an inserting way, the side surface of the directional suction pipe 7 is connected with the output end of the lifting assembly 4, and the lifting assembly 4 is used for driving the directional suction pipe 7 to move up and down. This kind of structure is convenient for the use of water pump 5, and the water pump 5 cooperation dirt absorbing pipe 38 of being convenient for adsorbs the filth of filter core inside to be convenient for improve the effect of clearing up the filter core, and directional straw 7 can directional absorption multi-media filter core 8, avoids the extravagant of suction, can further improve the filtration of clearing up multi-media filter core 8 like this.
The multi-medium filter element 8 is provided with a plurality of, and a plurality of multi-medium filter elements 8 are evenly arranged on the inner side of the middle splicing part 2, guide plates 84 are arranged between the top end and the bottom end of the multi-medium filter element 8 and two adjacent filter media, guide holes are evenly formed in the guide plates 84, the aperture sizes of the guide holes on each guide plate 84 are different, and the aperture sizes of the guide holes of the guide plates 84 are gradually reduced from top to bottom. When water enters the filter from the water inlet, if the aperture of the guide plate 84 is the same, the water is concentrated in the central area of the tank 01 due to inertia, and a cluster effect (similar to fountain water flow shape) is formed. The upper large-aperture baffle 84 can primarily disperse the water flow, and the lower small-aperture baffle 84 further restricts the water flow path, so that the water flow uniformly covers the whole filtering section. As the water flows downward, the impurity retention of the filter media layer increases gradually, resulting in increased resistance. By reducing the baffle hole aperture along the water flow direction, the upper baffle 84 can be made to distribute more flow (the large aperture reduces the local resistance), the lower baffle 84 compensates the resistance difference through the small aperture, and finally the balanced utilization of the full-layer filter medium is realized.
For example, when the upper media entraps impurities resulting in a 15% increase in drag, the small apertures of the lower baffle 84 may reduce the local flow rate by 8% maintaining overall flow stability. And the upper large aperture baffle 84 allows larger particulate impurities to pass through, avoiding "cake" plugging at the surface layer. The lower small-aperture guide plate 84 intercepts fine particles to realize graded filtration. If the bottom deflector 84 has too large an aperture, the high velocity water flow during backwash may lift the upper fine particulate media causing the media to mix or run off. By the bottom small-aperture guide plate 84, a stable water flow supporting layer can be formed, and the stability of the medium layer in the back flushing process is ensured. The aperture d of the deflector hole satisfies the following formula: Wherein, theIs the initial aperture of the uppermost baffle,Is the aperture attenuation coefficient of the lens,Is the height of the baffle from the top of the filter media layer.
The material of the deflector 84 is corrosion-resistant high-strength plastic or metal alloy, and the thickness of the deflector 84The determination is made according to the following equation: Wherein, theFor the maximum pressure to which the baffle is subjected,For the span of the baffle plate,Is an allowable stress for the material and is a high-temperature,Is the width of the deflector.
As shown in FIG. 6, a plurality of support legs 11 are uniformly arranged on the edge of the bottom surface of the lower splicing part 1, first bolt holes 12 are formed in the bottom ends of the support legs 11, the support legs 11 are used for supporting the whole filter conveniently, and the first bolt holes 12 are used for fixing the whole filter conveniently through bolts. The bottom end of the lower splicing part 1 is provided with a bottom pipe 15, the end part of the bottom pipe 15 is of a T-shaped structure, the end part of the bottom pipe 15 is provided with two openings which are respectively used as a purified water outlet and a back flushing water inlet, the bottom pipe 15 is provided with a first water quality monitoring sensor 151, and the first water quality monitoring sensor 151 is convenient for monitoring the water quality at the water outlet. The two openings at the end part of the bottom pipe 15 are both connected with a first electric control valve 152, the bottom pipe 15 is responsible for discharging purified water, and simultaneously backwash water flow is conveniently introduced during backwash, the first electric control valve 152 is convenient for respectively controlling the two openings of the bottom pipe 15, and is convenient for closing the inlet of backwash water when discharging purified water, and closing the purified water outlet when in backwash.
As shown in figures 5, 7 and 9, the positions, close to the top end and the bottom end, of the inner side of the middle splicing part 2 are respectively provided with a mounting plate 22, a plurality of mounting holes 23 are uniformly formed in the mounting plates 22, and the inner sides of the mounting holes 23 at the top of the inner side of the middle splicing part 2 are respectively provided with internal threads, and the mounting holes 23 are used for conveniently mounting the multi-medium filter element 8, so that the structure ensures that seawater can only flow from the top to the bottom of the middle splicing part 2 through the multi-medium filter element 8, the seawater can be conveniently and effectively filtered, and meanwhile, the structure also facilitates the independent replacement of each multi-medium filter element 8, so that the problem that the medium of the traditional multi-medium filter is difficult to replace is solved, and the flexibility of using the multi-medium filter is greatly improved. The middle splice 2 side is equipped with controls the case 21, controls the case 21 and is used for linking to each other with each automatically controlled part, and then controls whole filter, makes things convenient for the operation and the use of whole filter. The connecting disc 14 is arranged at two ends of the middle splicing part 2, the top end of the lower splicing part 1 and the bottom end of the upper splicing part 3, a plurality of connecting holes 141 are uniformly formed in the connecting disc 14, the adjacent connecting discs 14 are connected through bolts, the structure is convenient and stable to connect the whole tank body 01, and sealing treatment is performed at two ends of the middle splicing part 2, the top end of the lower splicing part 1 and the upper splicing part 3, so that the problem of water leakage is avoided.
As shown in fig. 9, the two sides of the dirt sucking pipe 38 are provided with ultrasonic wave generating terminals 33, the ultrasonic wave generator 31 is connected with the ultrasonic wave generating terminals 33 through the lead wires 32, and the structure is convenient for matching with the ultrasonic wave generator 31 to emit ultrasonic waves so as to be convenient for cleaning dirt in the multi-medium filter element 8 during back flushing. The support plate 34 is arranged on one side of the top end of the upper splicing part 3, the perforation 35 is arranged on the support plate 34, and the water pump 5 is conveniently installed by matching the support plate 34 with the perforation 35, so that the operation of the water pump 5 is convenient. The other side of the upper splicing part 3 is provided with a water inlet pipe 36, the water inlet pipe 36 is provided with a second water quality monitoring sensor 361, and the second water quality monitoring sensor 361 is convenient for monitoring the water quality of the seawater at the water inlet pipe 36. The end of the water inlet pipe 36 is provided with a first electric control valve 152, and the first electric control valve 152 is convenient for controlling the opening and closing of the water inlet pipe 36. The upper splicing part 3 is provided with the mounting table 37 along one side of the dirt absorbing pipe 38, the middle part of the mounting table 37 is provided with the through hole 371, the output end of the lifting assembly 4 passes through the upper splicing part 3, the stable use of the lifting assembly 4 is facilitated, and the sealing connection between the lifting assembly 4 and the upper splicing part 3 is also facilitated. An ultrasonic generator is arranged at the top of the tank body and emits high-frequency ultrasonic waves in the back flushing process, and the ultrasonic generator 31 emits ultrasonic waves with powerThe determination is made according to the following equation:
Wherein, theAs a function of the power coefficient,Is the density of the seawater, and the seawater is the density of the seawater,In order to filter the effective volume of the tank body,For the change of impurity concentration in seawater before and after back flushing,Is the back flushing time.
As shown in fig. 10, the lifting assembly 4 includes a driving cylinder 41 and a connecting plate 42, wherein the driving cylinder 41 may be one of an electric cylinder, an air cylinder and a hydraulic cylinder, so that the driving cylinder 41 can conveniently drive the directional straw 7 to move up and down. The fixed plates 411 are arranged on two sides of the driving cylinder 41, a plurality of fixed holes 412 are formed in the fixed plates 411, the two fixed plates 411 are clamped on two sides of the mounting table 37, the driving cylinder 41 is fixed on the mounting table 37 through bolts penetrating through the fixed holes 412, the structure ensures that the driving cylinder 41 is stably connected with the mounting table 37, and the driving cylinder 41 is convenient to use stably. The driving cylinder 41 output end is provided with a telescopic rod 413, the telescopic rod 413 passes through the through hole 371, the bottom end of the telescopic rod 413 is provided with the pressing plate 414, the bottom end of the pressing plate 414 is provided with the stud, the stud is provided with the pressing cap 415, one end of the connecting plate 42 is provided with the first sleeving hole 421, the stud passes through the first sleeving hole 421, the pressing cap 415 is arranged at one end of the stud, which passes through the first sleeving hole 421, and the pressing cap 415 is pressed on the connecting plate 42, and the structure is convenient for the driving cylinder 41 to be stably connected with the connecting plate 42 and is convenient for the installation and the use of the connecting plate 42. The connecting plate 42 other end is equipped with the second and cup joints the hole 422, and the second cup joints the hole 422 cover and establishes on directional straw 7, and connecting plate 42 evenly is equipped with a plurality of first equipment holes 423 along second cup joints the hole 422 edge for connecting plate 42 links to each other with directional straw 7, and then conveniently drives directional straw 7 through the flexible of actuating cylinder 41 and reciprocate, and the convenience is when not carrying out the back flush, rises directional straw 7, when carrying out the back flush, drives down straw and pushes down for directional straw 7 links to each other with multi-media filter core 8.
As shown in fig. 11, the output end of the water pump 5 is provided with two external connection pipes 51, the end part of the external connection pipe 51 is provided with a switching cap 52, and the two external connection pipes 51 are respectively used as a water suction end and a water discharge end of the water pump 5, so that the water pump 5 is conveniently connected with the sewage suction pipe 38 and an external sewage discharge pipe. The bottom end of the water pump 5 is provided with the connecting stud 53, the connecting stud 53 passes through the through hole 35, and one end of the connecting stud 53 passing through the through hole 35 is provided with the screw cap 54, and the screw cap 54 is tightly pressed on the bearing plate 34, so that the water pump 5 is stably installed on the bearing plate 34.
As shown in FIG. 13, the directional suction pipe 7 is provided with a plurality of branch pipes 71, the bottom ends of the branch pipes 71 are respectively provided with a directional suction head 72 which is aligned with the multi-medium filter element 8, the bottom ends of the directional suction heads 72 are provided with an inserting ring 73, the top ends of the multi-medium filter elements 8 can be inserted when the directional suction heads 72 move downwards, and the structure can ensure that each directional suction head 72 is inserted at the top of the multi-medium filter element 8, so that the multi-medium filter element 8 can be directly adsorbed, and the effect of back flushing on the multi-medium filter element 8 can be quickened by matching with the back flushing water flow, so that the multi-medium filter element 8 is greatly convenient to clean. The top of the directional straw 7 is provided with a telescopic insertion tube 76, the top of the side surface of the telescopic insertion tube 76 is provided with a plurality of sealing rings 77, and the top of the telescopic insertion tube 76 is inserted into the inner side of the bottom of the dirt suction tube 38, so that the directional straw 7 can conveniently move up and down. The assembly plate 74 is arranged at the top of the side face of the directional straw 7, a plurality of second assembly holes 75 are formed in the assembly plate 74, the second assembly holes 75 are aligned with the first assembly holes 423, the assembly plate 74 is connected with the connecting plate 42 through bolts, the directional straw 7 is conveniently connected with the lifting assembly 4, and the lifting assembly 4 is conveniently used for driving the directional straw 7 to move up and down.
As shown in fig. 14 and 15, the top of the multi-medium filter element 8 is provided with an adapter 81, and the side surface of the multi-medium filter element 8 is provided with a threaded connection part 82 along the lower part of the adapter 81, the threaded connection part 82 is in threaded connection with the mounting hole 23 at the top of the middle splicing part 2, and the structure is convenient for flexible disassembly and assembly of the multi-medium filter element 8 and convenient for replacing the multi-medium filter element 8. The bottom of the side surface of the multi-medium filter element 8 is provided with a sealing gasket 83, the sealing gasket 83 is extruded on the inner side of a mounting hole 23 at the bottom of the middle splicing part 2, the purpose of sealing treatment between the multi-medium filter element 8 and the middle splicing part 2 is achieved, the medium inside the multi-medium filter element 8 is sequentially provided with modified anthracite 85, fused quartz sand 86, rare earth permanent magnet filter materials 87 and corrosion-resistant ceramic gravel 88 from top to bottom, and the filter medium with the structure can be used for more efficiently filtering seawater. The specific parameters of each filter media are shown in table 1.
TABLE 1
| Dielectric layer | Material of material | Particle size | Layer thickness | Operating parameters |
| Upper layer | Modified anthracite | 1.5-2.0mm | 350mm | The back flush strength is 15L/(m 2. Dbreak. S), the frequency is 8h |
| Middle layer | Fused silica sand | 0.6-1.0mm | 600mm | The filtering flow rate is 8-10m/h |
| Lower layer | Rare earth permanent magnet filter material | 0.3-0.5mm | 250mm | Magnetic field strength 0.3T |
| Support layer | Corrosion-resistant ceramic gravel | 2-16mm | 250mm | The water distribution uniformity error is less than 5 percent |
As shown in fig. 4 and 6, the air compressor 6 is further included, a spray pipe 13 is arranged on the side face of the lower splicing part 1, a connecting cap 131 is arranged at one end, facing the outer side, of the spray pipe 13, the connecting cap 131 is connected with the exhaust end of the air compressor 6, and the air compressor 6 can conveniently spray gas through the spray pipe 13, so that the purpose of air-water mixed back flushing is achieved. The synergistic effect of the compressed air and the backwash water has obvious advantages in the aspects of improving the cleaning efficiency, reducing the energy consumption, protecting the filter medium and the like. One end of the inner side of the lower splicing part 1 of the spray pipe 13 is connected with a ring pipe 132, the positions of the ring pipe 132 and the spray pipe 13 aligned with the multi-medium filter element 8 are respectively provided with a spray head 133, the bottom of the spray head 133 is provided with a one-way valve, the intelligent gas is ensured to spray out of the spray head 133, and water cannot flow backward to the ring pipe 132 and the inner side of the spray pipe 13 through the spray head 133.
As shown in fig. 12, the bottom end of the air compressor 6 is provided with a plurality of fixing legs 61, and the fixing legs 61 are provided with second bolt holes 62, so that the air compressor 6 is conveniently fixed by bolts, and the air compressor 6 is conveniently used. The air compressor 6 is provided with a pressure gauge 63 at the air outlet end, and the pressure gauge 63 is used for conveniently measuring the air pressure inside the tank 01 of the air compressor 6. And the air outlet end of the air compressor 6 is connected with an exhaust pipe 64, and a second electric control valve 65 is arranged on the exhaust pipe 64 and used for controlling the opening and closing of the exhaust pipe 64, so that air flow supply is facilitated during back flushing.
As shown in FIG. 8, a microprocessor is integrated in the control box 21, the microprocessor is connected with a data acquisition module, a backwash control module, a communication module, a power module and an ultrasonic control module, the control box 21 is electrically connected with a first electromagnetic valve, a second electromagnetic valve, a first water quality monitoring sensor 151, a second water quality monitoring sensor 361, a water pump 5 and a driving cylinder 41, the microprocessor is convenient for processing data of the whole filter, and the data acquisition module is used for monitoring water quality of a water inlet and a water outlet in cooperation with the first water quality monitoring sensor 151 and the second water quality monitoring sensor 361 and monitoring water quality parameters such as turbidity, suspended matter content and the like of seawater in real time. The control box 21 automatically adjusts the filtration and backwash procedures according to preset water quality standards and parameter ranges. For example, when the water quality of the water outlet does not reach the standard, the control box 21 automatically starts a back flushing program, and when the water quality of the water inlet is good, the filtering period is properly prolonged, and the running efficiency of the equipment is improved. The back flush control module is used for controlling the opening of the inlet of back flush water and closing the water purification outlet simultaneously so as to facilitate the back flush procedure, the communication module is used for being connected with the terminal equipment, the data which facilitate the operation of the filter are fed back to the terminal equipment in real time, and the power supply module is used for receiving electricity so as to facilitate the power supply of each component. The ultrasonic control module is used for controlling the operation of the ultrasonic generator 31, so that the ultrasonic generator 31 is conveniently started during back flushing, and the cleaning of the multi-medium filter element 8 is conveniently and well completed. The first water quality monitoring sensor 151 and the second water quality monitoring sensor 361 respectively monitor the water quality of the water inlet end and the water outlet end of the tank 01, and the control box 21 automatically adjusts the filtering and back flushing procedures according to the preset water quality standard and the parameter range, and the filtering periodCalculated according to the following formula:
Wherein, theAs a reference to the period of the filtering,Is the water quality parameter value of the water inlet,Is a preset standard value of water quality,Is the decay constant.
As shown in fig. 4 and 5, the side walls of the lower splice part 1, the middle splice part 2 and the upper splice part 3 are all hollow, and the hollow space is set as a heat insulation interlayer, and the heat insulation interlayer is filled with heat insulation materials. Therefore, heat dissipation can be reduced, water temperature stability in the filtering process is maintained, the filtering effect is improved, and the structural strength of the tank body 01 can be enhanced to a certain extent.
The working principle is that when in use, the whole filter is assembled, and the filter is fixed at a designated position, so that the filter is connected with each pipeline. When seawater is filtered, the lifting assembly 4 lifts the directional suction pipe 7, so that the top end opening of the multi-medium filter element 8 is opened, seawater is injected into the tank body 01 through the water inlet pipe 36, and flows through the middle splicing part 2 through the multi-medium filter element 8, the seawater flowing through the middle splicing part 2 is purified, and the purified seawater flows out of the tank body 01 through the purified water outlet of the bottom pipe 15. And because the inside of the multi-medium filter element 8 is provided with a plurality of guide plates 84 from top to bottom, water flows uniformly through each layer of medium, so that seawater can be filtered uniformly, and the filtering effect on the seawater is improved. When the multi-medium filter element 8 is used for a period of time, the first water quality monitoring sensor 151 monitors that the water quality of the water outlet does not reach the standard, the control box controls the first electromagnetic valve at the water purifying outlet of the bottom pipe 15 to be closed, and opens the first electromagnetic valve at the backwash water inlet, so that backwash water enters the tank body 01 through the bottom pipe 15, meanwhile, the lifting component 4 drives the directional suction pipe 7 to be pressed down, so that the directional suction head 72 is inserted into the opening at the top end of the multi-medium filter element 8, then the water pump 5 and the ultrasonic generator 31 operate, the water pump 5 can generate suction force on the multi-medium filter element 8 after operating, thus dirt inside the multi-medium filter element 8 and backwash water can be forced to flow through the multi-medium filter element 8 rapidly, the purpose of cleaning the inside of the multi-medium filter element 8 is achieved, and the ultrasonic wave emitted by the ultrasonic generator 31 can enable dirt attached to be separated from the multi-medium filter element 8 rapidly, so that the cleaning effect on the multi-medium filter element 8 can be further improved. And sewage generated by back flushing is guided to the directional suction pipes 7 by the plurality of directional suction heads 72 for converging, and is discharged into a sewage discharge pipe from the water discharge end of the water pump 5 after converging, so that the aim of effectively cleaning the multi-medium filter element 8 is fulfilled. And in the back flushing process, the second electromagnetic valve can be opened, so that the air compressor 6 supplies air to the spray pipe 13 to realize air-water mixed back flushing, so that countless tiny bubbles can be formed when compressed air is released in water, the bubbles move to the vicinity of the surface of the filter medium along with water flow to be ruptured, local high pressure and strong shock waves are generated, and intractable pollutants (such as colloid and microbial mucous membrane) in the pores of the medium are instantaneously stripped. The cavitation effect is combined with the water flow shearing force, so that the pollutant stripping efficiency is improved by 40% -60% (compared with the traditional water backwashing which only depends on the water flow shearing), and meanwhile, the disturbance flow generated in the rising process breaks the two-dimensional laminar flow state of the water backwashing, so that a complex turbulent vortex is formed. The turbulent motion enables the backwash medium flow to penetrate into the filter layer pores and clean dead corners which are difficult to reach by traditional water backwash.
In summary, the multi-medium filter provided by the application has the advantages that the plurality of detachable multi-medium filter cores 8 are arranged in the tank body 01, impurities in seawater can be effectively filtered by utilizing the multi-medium filter cores 8, the guide plates 84 are arranged at the two ends of the multi-medium filter cores 8 and between two adjacent layers of media, the guide plates 84 are uniformly provided with the guide holes with different apertures, the aperture size is gradually reduced along the water flow direction, and the structure can ensure that water flow can uniformly pass through each layer of media, so that the purification effect on seawater is improved. And the top end of the tank body 01 is provided with the water pump 5 to be matched with the directional suction pipe 7 for use, and when in back flushing, the directional suction pipe 7 is inserted into the top end of the filter element, so that the negative pressure suction of the filter element is realized, the back flushing water flow can be increased to quickly pass through the multi-medium filter element 8, and impurities in the multi-medium filter element 8 can be conveniently and rapidly removed. By arranging the ultrasonic generator 31 at the top of the upper splicing part 3, ultrasonic waves opposite to backwash water flow are emitted by the ultrasonic generator 31, and the water flow flows upwards from the bottom during backwash and is coupled with the ultrasonic waves downwards from the top. The synergistic effect of the upward water flow and the downward ultrasonic can effectively strip the pollutant attached to the surface of the medium. Through being equipped with spray tube 13 in lower splice 1 inboard, spray tube 13 top is equipped with jet connection, and spray tube 13 external connection has air compressor 6, and jet connection aligns every multi-media filter core 8, can form the back flush mode of water-gas mixture like this to improve and carry out effectual clearance to multi-media filter core 8, extension multi-media filter core 8's life.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.