Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a control system of a shale gas supply device at a wellhead of a generator of a micro gas turbine, which realizes stable control and automatic liquid discharge of a water hydrocarbon dew point under the condition of fluctuation of working conditions, reduces the risks of tripping and gas cross, ensures the normal and stable operation of the micro gas turbine, reduces the overall operation cost, and provides stable power supply for electric equipment in shale gas fracturing operation.
The invention aims at achieving the technical measures that a control system of a shale gas supply device of a wellhead of a micro gas turbine generator comprises a working condition parameter signal acquisition system (1), a parameter setting system (2), a logic judgment command system (3), a data storage remote transmission system (4), a control protection system (5) and a micro gas turbine power generation system (13), wherein the control protection system (5) comprises a particle liquid drop control system (6), a temperature control system (7), a pressure control system (8), a liquid level control system (9), a water hydrocarbon dew point control system (10), a fine treatment control system (11) and a system safety protection system (12) which are independently and parallelly arranged, the water hydrocarbon dew point control system (10) is used for determining dew point values of different working conditions, realizing stable control of water hydrocarbon dew points under working condition fluctuation, the liquid level control system (9) is used for realizing automatic pollution discharge under the working condition fluctuation, the fine treatment control system (11) is used for realizing accurate pollution discharge of the liquid level control system (9) and continuous separation of water hydrocarbon of the shale gas, the working condition parameter signal acquisition system (1) transmits the judgment command system (3) to the logic judgment command system (3), the logic judgment command system (4) and the data storage remote control system (4) are respectively connected with the data storage remote control system (4), the miniature gas turbine power generation system (13) is respectively connected with the parameter setting system (2), the control protection system (5) and the data storage remote transmission system (4).
Further, the water hydrocarbon dew point control system (10) comprises a refrigerating unit, a cooler refrigerating agent bypass valve, a pipeline and pipeline accessories, wherein the refrigerating unit is used for realizing condensation of water vapor and heavy hydrocarbon in shale gas, the cooler is used for realizing heat exchange between the refrigerating agent and the shale gas, and the cooler refrigerating agent bypass valve is used for adjusting the flow of the refrigerating agent of the cooler.
Further, the finishing control system (11) comprises a differential pressure transmitter, a temperature compensation sensor, a flowmeter, a cable and a cable accessory, wherein the flowmeter is used for acquiring an actual shale gas flow value, and the differential pressure transmitter and the temperature compensation sensor are used for correcting the flowmeter.
Further, the liquid level control system (9) comprises a liquid level detection element, an automatic drain valve, a manual drain valve, a one-way valve, a separator and a drain pipe, wherein the manual drain valve and the automatic drain valve are connected in parallel for draining, and the liquid level detection element is used for realizing real-time monitoring of a liquid level value.
Compared with the prior art, the method has the advantages that the water hydrocarbon dew point value under different working conditions is controlled through the water hydrocarbon dew point determining system, condensation and precipitation of water vapor and heavy hydrocarbon under the condition of fluctuation of the working conditions are achieved, stable control of the water hydrocarbon dew point is achieved, the requirement of the micro gas turbine on the shale gas water hydrocarbon dew point is met, normal and stable operation of the micro gas turbine is guaranteed, the fine treatment control system performs precise control of pollution discharge according to the fluctuation condition of the actual working conditions, continuous precipitation of the shale gas outlet water hydrocarbon is prevented, meanwhile, the overall operation cost is reduced, and the liquid level control system achieves automatic liquid discharge under the fluctuation of the different working conditions and reduces the risk of tripping and gas cross.
The invention is described in detail below with reference to the drawings and the detailed description.
Detailed Description
As shown in fig. 1, the control system of the shale gas supply device of the micro gas turbine generator wellhead comprises a working condition parameter signal acquisition system 1, a parameter setting system 2, a logic judgment command system 3, a data storage remote transmission system 4, a control protection system 5 and a micro gas turbine power generation system 13, wherein the control protection system 5 comprises a particle liquid drop control system 6, a temperature control system 7, a pressure control system 8, a liquid level control system 9, a water hydrocarbon dew point control system 10, a fine treatment control system 11 and a system safety protection system 12 which are independently and parallelly arranged, the water hydrocarbon dew point control system 10 is used for determining dew point values of different working conditions and realizing stable control of water hydrocarbon dew points under working condition fluctuation, the liquid level control system 9 is used for realizing automatic pollution discharge under working condition fluctuation, the fine treatment control system 11 is used for realizing accurate pollution discharge of the liquid level control system 9 and preventing continuous precipitation of water hydrocarbon of shale gas outlet, the working condition parameter signal acquisition system 1 transmits acquisition signals to the logic judgment command system 3, the logic judgment command system 3 is respectively connected with the parameter setting system 2, the control protection system 5 and the data storage remote transmission system 4, and the micro gas turbine power generation system 5 are respectively connected with the micro gas turbine power generation system 4 and the data storage remote transmission system 4.
The working condition parameter signal acquisition system 1 comprises a temperature detection element, a pressure detection element, a flow detection element, a pressure difference detection element, a liquid level detection element, a signal cable and a pressure root valve, wherein the working condition parameter signal acquisition system 1 detects the temperature through the temperature detection element and transmits the temperature to the logic judgment command system through the signal cable, and similarly, the flow detection element, the pressure difference detection element and the liquid level detection element transmit detected flow, pressure difference and liquid level signals to the logic judgment command system 3.
The parameter setting system 2 comprises a signal input part, a transmission cable and a storage part, the parameter setting system 2 provides an input interface and a man-machine interaction interface, performs manual or automatic input of control programs and set values, and transmits the control programs and the set values to the logic judgment command system 3 through the cable, and meanwhile, the parameter setting system 2 embeds a parameter setting range to meet automatic acquisition of parameters under different working conditions.
The digital signals of key parameters such as the air inlet pressure, temperature, rotating speed, vibration value and the like of the micro gas turbine power generation system 13 are transmitted through interfaces in the parameter setting system.
The logic judgment command system 3 comprises a logic control unit, an I/O input/output unit, a power supply and an instruction storage unit, and is used for meeting judgment of different parameters.
The data storage remote transmission system 4 comprises a storage unit, a transmission unit, a data conversion unit and a display unit, and can display parameters in real time and retrieve and analyze at a certain moment in the operation process of the shale gas supply device of the wellhead of the single or multiple micro gas turbine generators so as to realize remote scheduling decision, remote emergency stop and the like.
The particle liquid drop control system 6 comprises a particle liquid drop filtering unit, an inspection cleaning unit and a pipeline unit, wherein the particle liquid drop filtering unit is used for removing most particles and liquid drops which are larger than 10um in shale gas, and the inspection cleaning unit is used for periodically inspecting and cleaning to ensure that the removal efficiency is stabilized to be more than 99-99.9%, so that the control of the gas turbine on the content and the size of the particles and the liquid drops is satisfied.
The temperature control system 7 comprises a heating unit and a cooling unit, the cooling unit adopts a refrigerator, the heating unit adopts an electric heater, and the temperature control system 7 is used for meeting the requirement of the gas turbine on the temperature of the inlet air. Alternatively, the cooling unit may employ a chiller dryer, and the heating unit may employ a hot water/steam/water jacket furnace.
The pressure control system 8 comprises a pressure regulating valve, a pressure taking pipe and a root valve, and meets the requirement of the gas turbine on the inlet pressure.
The water hydrocarbon dew point control system 10 comprises a refrigerating unit, a cooler, a heat preservation component, a circulating water pump, a gas-liquid separator, a cooler secondary refrigerant inlet valve, a cooler natural gas inlet valve, a cooler secondary refrigerant bypass valve, a pipeline and pipeline accessories, wherein the refrigerating unit is used for realizing condensation of water vapor and heavy hydrocarbon in shale gas, the cooler is used for realizing heat exchange between the secondary refrigerant and the shale gas, and the cooler secondary refrigerant bypass valve is used for adjusting the flow of the cooler secondary refrigerant and is suitable for the working condition of shale gas flow change in a larger range. Obtaining a shale gas inlet temperature variation range, a flow variation range, a pressure variation range, a component variation range and a water content variation range through a pre-prediction means, further determining the highest value and the lowest value of a dew point, determining n intermediate values (n is more than or equal to 0) through an interpolation method, finally obtaining dew point theoretical values under different working conditions, namely, the highest value, the lowest value and the intermediate value 1. The shale gas components are built in the parameter setting system 2, operators can obtain real-time shale gas components through a gas chromatograph and store the real-time shale gas components into a shale gas parameter group of the parameter setting system 2, the logic judgment command system 3 screens out the closest group of values in the shale gas parameter group of the parameter setting system 2 according to the shale gas components transmitted by the parameter setting system 2 and the shale gas inlet temperature, pressure and flow transmitted by the working condition parameter signal acquisition system 1, takes the flow rate of the secondary refrigerant and the temperature of the secondary refrigerant at the inlet of the cooler as the current target values, controls the refrigerating unit according to the required temperature of the secondary refrigerant at the inlet of the cooler, the working condition parameter signal acquisition system 1 is provided with a temperature detection element at the inlet of the cooler, detects the actual temperature of the secondary refrigerant at the inlet of the cooler in real time and converts the actual temperature into an electric signal to be transmitted to the logic judgment command system 3, the parameter setting system 2 is also provided with an allowable temperature deviation range, if the deviation between the temperature detected by the working condition parameter signal acquisition system 1 and the target value exceeds the allowable temperature deviation range, the logic judgment command system 3 sends out a regulating command, and an operator regulates the opening of a coolant bypass valve of the cooler until the requirement is met, so that the continuous stability of the outlet temperature of the refrigerating unit under different working conditions is realized, the water vapor and heavy hydrocarbon are condensed and separated out under the condition of fluctuation of the working conditions, the stable control of the water hydrocarbon dew point is achieved, the requirement of the micro gas turbine on the shale gas water hydrocarbon dew point is met, and the normal stable operation of the micro gas turbine is ensured. Alternatively, the refrigerating unit may be replaced by a cold drier, the flow of refrigerating medium may be controlled automatically, and the refrigerating medium inlet and outlet valves of the cooler may be replaced by electric or pneumatic regulating valves.
The liquid level control system 9 comprises a liquid level detection element, an automatic blowdown valve, a manual blowdown valve, a one-way valve, a separator and a blowdown pipe, wherein the manual blowdown valve and the automatic blowdown valve are connected in parallel for blowdown, the liquid level detection element is used for realizing real-time monitoring of the liquid level value, the lowest liquid level value under different working conditions is determined according to the shale gas inlet air temperature fluctuation range, the flow fluctuation range and the pressure fluctuation range which are obtained by a pre-prediction means, the lowest liquid level value under different working conditions is stored in the parameter setting system 2, meanwhile, the high-high stop value, the high-alarm value, the high-regulation value, the low-alarm value and the low-stop value of the liquid level are set and are stored in the parameter setting system 2, the working condition parameter signal acquisition system 1 detects the shale gas inlet air temperature, the flow rate and the pressure in real time and converts the shale gas inlet air temperature and the pressure into electric signals to be transmitted to the logic judgment command system 3, the logic judgment command system 3 searches the lowest liquid level value which is allowed under the current working conditions through the received temperature, the lowest liquid level value, the logic judgment command system 3 is used as the lowest liquid level value allowed under the current working conditions, the lowest liquid level value is detected in real time through the detection element of the liquid level control system 9, when the liquid level reaches the high-regulation value, the automatic command value is set by the automatic command valve is set, the automatic command valve can be closed when the automatic command valve is reached, the blowdown valve is opened, and the blowdown valve is opened when the automatic command is opened, and the blowdown valve is reached. Alternatively, the low shut-down value may be set to be automatically adjusted, the liquid level detection element may be a magnetic flap or other type of liquid level gauge, and the automatic blow-down valve may be a pneumatic on-off valve or an axial flow pneumatic on-off valve or an electric axial flow on-off valve or a pneumatic electric adjustment valve.
The finishing control system 11 comprises a differential pressure transmitter, a temperature compensation sensor, a flowmeter, a pressure compensation sensor, a cable and a cable accessory, wherein the flowmeter is used for acquiring an actual flow value of shale gas, and the differential pressure transmitter and the temperature compensation sensor are used for correcting the flowmeter. According to the logic judgment command system 3, the closest set of values screened out from the shale gas parameter set of the parameter setting system 2 is used as the current dew point value, the drain capacity required by the liquid level control system 9 is obtained according to the obtained current dew point value and the flow fluctuation range of the shale gas obtained by prediction in the earlier stage, the theoretical time range of the automatic drain valve required to be opened is determined by combining the diameter of the separator, the drain pipe diameter and the obtained shale gas actual flow value and stored in the parameter setting system 2, the flowmeter measures the shale gas actual flow in the theoretical time range and stores the shale gas actual flow in the parameter setting system 2, the logic judgment system 3 calculates the accumulated flow of the shale gas before the automatic drain valve is opened and converts the accumulated flow into the liquid quantity required to be discharged by the separator, the real-time liquid level is combined to obtain the actual time required to be opened of the automatic drain valve, the obtained actual time is compared with the fixed liquid storage time of the liquid level control system 9, the smaller value between the obtained actual time is the optimal opening time of the automatic drain valve, the optimal opening time of the automatic drain valve is further improved, the capability of preventing the drain gas from being in series is further improved, and the accurate control of the dew point is further realized. According to the obtained current dew point value, a temperature control target value z is obtained through a temperature control target value z= (the current dew point value +y) ° (y is larger than or equal to 0, y is the margin required by the gas turbine and corresponds to the requirement of the gas turbine), a parameter setting system 2 is provided with an allowable temperature deviation range, a logic judgment command system 3 compares the shale gas outlet temperature acquired by a working condition parameter signal acquisition system 1 with the temperature control target value z to prevent the continuous precipitation of shale gas outlet water hydrocarbon, when the acquired temperature is lower than the temperature control target value z, the logic judgment command system 3 sends a command to start a heating unit of the temperature control system 7 to increase the temperature until the allowable temperature deviation range approaches the temperature control target value z, when the acquired temperature is higher than the temperature control target value z, the logic judgment command system 3 sends a command to close the heating unit, the system power consumption is saved, and the whole running cost is reduced,
The system safety protection system 12 comprises a cut-off valve, a safety release valve, a pressure release valve, a manual release valve, a warning lamp, a buzzer and a pipeline cable, the system safety protection system 12 comprises a pressure sub-protection system, the pressure sub-protection system is provided with triple protection, the pressure release valve and the manual release valve are respectively arranged in a particle liquid drop control system 6, a finishing control system 11 and a pressure control system 8, the timely release of pressure in each place in emergency is met, the first heavy pressure protection is realized, a working condition parameter signal acquisition system 1 transmits measured point pressure to a logic judgment command system 3 through a cable, when an alarm value is reached, the warning lamp and the buzzer are used for warning, the logic judgment command system 3 outputs a signal, warning content is displayed in a man-machine interaction interface of a parameter setting system 2 for judgment and operation by an operator, the second heavy pressure protection is realized, and when the detected pressure of the working condition parameter signal acquisition system 1 reaches the set cut-off pressure, the logic judgment command system 3 sends a command to the cut-off valve in time, and the third heavy pressure protection is realized.
According to the technical scheme, the water hydrocarbon dew point value under different working conditions is determined through the water hydrocarbon dew point control system, condensation and precipitation of water vapor and heavy hydrocarbon under the condition of fluctuation of the working conditions are realized, stable control of the water hydrocarbon dew point is achieved, the requirement of the micro gas turbine on the shale gas water hydrocarbon dew point is met, normal and stable operation of the micro gas turbine is guaranteed, the fine treatment control system performs precise control of pollution discharge according to the fluctuation condition of the actual working conditions, continuous precipitation of the shale gas outlet water hydrocarbon is prevented, meanwhile, the overall operation cost is reduced, and the liquid level control system realizes automatic liquid discharge under the fluctuation of different working conditions and reduces the risk of tripping and gas cross.
It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.