CN103495293A - Technology for removing ash in ammonia desulphurization grout and equipment thereof - Google Patents

Abstract

The invention discloses a technology for removing ash in ammonia desulphurization grout and equipment thereof. The technology includes the following steps that first, pre-settling is conducted; second, primary settling is conducted, gravity settling is conducted on the grout after pre-settling, hydraulic retention time is 11-13 hours, the ash is further settled, and clear liquid is full and flows back to a gas desulphurization system; third, secondary settling is conducted, the grout is added with water and is washed after primary settling, then the washed grout is fully settled so that the ash can be further separated, settling time is 8-10 hours, the clear liquid is full and flows back to the gas desulphurization system, and bottom grout ash is separated; fourth, third settling is conducted, the bottom grout ash is separated and removed. The equipment mainly comprises a pre-settling groove, a primary settling groove, a secondary settling groove and an ash grout groove. By means of the technology for removing the ash in the ammonia desulphurization grout and the equipment thereof, the removal rate of the ash can reach 90%, the purity of ammonium sulfate products is greatly improved, faults caused by ash blockage of the desulphurization equipment are avoided, and heavy metal in the ash is also effectively prevented from flowing into farmland along with ammonium sulfate fertilizer so that secondary pollution can be avoided.

Description

In ammonia process of desulfurization slurries, lime-ash is removed technique and equipment thereof

Technical field

The present invention relates to the ammonia type flue gas desulfurizing technology, refer to that particularly in a kind of ammonia process of desulfurization slurries, lime-ash is removed technique and equipment thereof.

Background technology

Ammonia is a kind of good alkaline absorbent, and ammonia flue gas desulfurization technique utilizes these characteristics of ammonia, with the NH in the aqueous solution₃and SO₂the reaction for the basis, with ammoniacal liquor by the SO in waste gas₂remove, generate ammonium bisulfite and ammonium sulfite solution, obtain the ammonium sulfate slurries after oxidation, and then crystallizing and drying obtains ammonium sulfate products.It is high that the ammonia type flue gas desulfurizing technology has a desulfuration efficiency, by-product value is high, the advantages such as recycling economy, yet there is the problem of a whole industry of puzzlement in ammonia desulfurizing process, it is exactly the quality that the lime-ash accumulated in ammonia process of desulfurization slurries affects system operation and follow-up ammonium sulfate fertilizer, heavy metal in lime-ash can flow into farmland along with ammonium sulfate fertilizer simultaneously, and crops are polluted.

The method that tradition is removed lime-ash in ammonia process of desulfurization slurries mainly contains the mechanical filter method, and there is poor filtration effect in the method, and filter plant is not easy to operate, and equipment failure rate is high, and the high in cost of production defect, and the filter that domestic many covers are attempted operation is all in succession stopped using or removes; Also have producer to attempt the employing membrane filter method and carry out the lime-ash filtration, the method filter effect is better, but it is high to exist service condition to require, and film easily stops up, and treating capacity is little, and the problem such as filter membrane material is expensive, is difficult to be used widely.Therefore, find out and a kind ofly can efficiently remove the technology of lime-ash in ammonia process of desulfurization slurries, and make the removal of this technology energy widespread adoption lime-ash in ammonia process of desulfurization slurries just become problem demanding prompt solution.

Summary of the invention

Purpose of the present invention will provide lime-ash in a kind of ammonia process of desulfurization slurries to remove technique and equipment thereof exactly, and this technique is high to the removal efficiency of lime-ash, easily operation, and good economy performance.

For achieving the above object, the technical solution used in the present invention is: in a kind of ammonia process of desulfurization slurries, lime-ash is removed technique, comprises the following steps:

1) pre-sedimentation: ammonia process of desulfurization slurries are carried out to gravitational settling, preliminary sedimentation lime-ash, the supernatant liquor flowing full returns desulphurization system;

2) first grade subsides: the slurries after pre-sedimentation are carried out to gravitational settling again, and hydraulic detention time is 11～13 hours, further sedimentation lime-ash, and the supernatant liquor flowing full returns desulphurization system;

3) secondary sedimentation: the slurries after first grade subsides are added to water and washed, then the abundant sedimentation of slurries after washing is further separated to lime-ash, the sedimentation time is 8～10 hours, and the supernatant liquor flowing full returns desulphurization system, isolates bottom slag slurry;

4) three grades of sedimentations: the bottom slag slurry after the secondary sedimentation is carried out to gravitational settling again, and the supernatant liquor flowing full returns desulphurization system, isolates bottom ashe and is removed.

Further, in described step 3), by controlling washing times and amount of water, make after secondary settlement the quality percentage composition of ammonium sulfate≤6% in the slag slurry of bottom.

Further, described step 2) in, operating temperature is 30～70 ℃, slurry temperature is 40～60 ℃.

Further, in described step 3), operating temperature is 30～70 ℃, and slurry temperature is 40～60 ℃.

A kind of for realizing lime-ash eliminating equipment in ammonia process of desulfurization slurries that above-mentioned technique designs, comprise pre-deep gouge, the one-level stillpot, the two-stage precipitation groove, and slag stock tank, described pre-deep gouge is provided with flowing full mouth and slurries outlet, described one-level stillpot top is respectively equipped with slurry inlet and flowing full mouth, described one-level stillpot bottom is provided with the slurries outlet, the slurries outlet of described pre-deep gouge is connected with the slurry inlet of described one-level stillpot, described two-stage precipitation groove top is respectively equipped with the flowing full mouth, slurry inlet, and filler, the bottom of described two-stage precipitation groove is provided with the outlet of slag slurry, the slurries outlet of described one-level stillpot is connected with the slurry inlet of described two-stage precipitation groove, described slag stock tank top is respectively equipped with slag slurry inlet and flowing full mouth, described slag stock tank bottom is provided with the outlet of slag slurry, the slag slurry outlet of described two-stage precipitation groove is connected with the slag slurry inlet of described slag stock tank.

Further, described one-level stillpot top is cylindrical shape, bottom be 45 °～65 ° cone-shaped, be provided with the grout distribution device in described one-level stillpot, liquid level gauge, and thermometer.

Further, described one-level stillpot is provided with the accident slurry inlet, described one-level stillpot is connected with the accident slurry tank, is respectively equipped with flowing full mouth and slurries outlet on described accident slurry tank, and the slurries outlet on described accident slurry tank is connected with the accident slurry inlet of described one-level stillpot.The accident slurry tank is the same with pre-deep gouge, carries out therein preliminary sedimentation and can increase effect of settling.

Further, be connected with the first slush pump between the slurries outlet of described pre-deep gouge and the slurry inlet of described one-level stillpot, be connected with the accident slush pump between the slurries outlet of described accident slurry tank and the accident slurry inlet of described one-level stillpot, be connected with the second slush pump between the slurries outlet of described one-level stillpot and the slurry inlet of described two-stage precipitation groove, the slag slurry outlet of described slag stock tank is provided with the slag stock pump.The slag stock pump is delivered to fixed location by the slurry of the slag in the slag stock tank and is recycled.

Compared with prior art, the present invention has following advantage:

One, the present invention utilizes natural subsidence, through four times gradually the process of sedimentation separation properly realized the efficient removal of lime-ash in ammonia process of desulfurization slurries, make lime-ash clearance in ammonia process of desulfurization slurries reach more than 90%, and then the sulphur ammonium nitrogen content that makes clear liquid obtain after crystallization, separation, drying reaches more than 20.50%, meet the quality requirement of GB535-1995 to the ammonium sulfate certified products, significantly improved the purity of ammonium sulfate products.

Its two, technique of the present invention effectively removed the lime-ash in ammonia process of desulfurization slurries, thoroughly avoided desulphurization plant to stop up because of lime-ash the fault caused; Also effectively avoid the heavy metal in the lime-ash to flow into farmland with ammonium sulfate fertilizer crops have been polluted, avoided causing secondary pollution.

Its three, in technique of the present invention, the precipitation of lime-ash adopts continuous natural subsidence mode, the concentrate that is rich in lime-ash after sedimentation can be separated effectively with clear liquid, saves energy consumption, controls simple.

The accompanying drawing explanation

The structural representation that Fig. 1 is lime-ash eliminating equipment in a kind of ammonia process of desulfurization slurries.

The specific embodiment

Below in conjunction with drawings and Examples, the present invention is further illustrated, but the present invention is not limited to following embodiment.

Lime-ash eliminating equipment in a kind of ammonia process of desulfurization slurries as shown in Figure 1, comprise the pre-deep gouge 1 with stock inlet, pre-deep gouge 1 is provided with flowingfull mouth 2 andslurries outlet 3, pre-deep gouge 1 is connected with one-level stillpot 4, one-level stillpot 4 tops are respectively equipped withslurry inlet 5 and flowingfull mouth 6, one-level stillpot 4 bottoms are provided withslurries outlet 7, theslurries outlet 3 of pre-deep gouge 1 is connected with theslurry inlet 5 of one-level stillpot 4, being provided withgrout distribution device 17 in one-level stillpot 4 is uniformly distributed slurries, also be provided with gauge glass in one-level stillpot 4, radar level gauge, the annexes such as thermometer, so that the operator grasps the ruuning situation of one-level stillpot 4 at any time, also be provided withaccident slurry inlet 18 on one-level stillpot 4, one-level stillpot 4 is connected withaccident slurry tank 19, be respectively equipped with flowingfull mouth 20 andslurries outlet 21 onaccident slurry tank 19,slurries outlet 21 onaccident slurry tank 19 is connected with theaccident slurry inlet 18 of described one-level stillpot 4, one-level stillpot 4 is connected with two-stage precipitation groove 8, two-stage precipitation groove 8 tops are respectively equipped with flowingfull mouth 9,slurry inlet 10, and filler 11, the bottom of two-stage precipitation groove 8 is provided withslag slurry outlet 12, theslurries outlet 7 of one-level stillpot 4 is connected with theslurry inlet 10 of two-stage precipitation groove 8, also be provided withagitator 28 in two-stage precipitation groove 8, two-stage precipitation groove 8 is connected withslag stock tank 13,slag stock tank 13 tops are respectively equipped withslag slurry inlet 14 and flowingfull mouth 15,slag stock tank 13 bottoms are provided withslag slurry outlet 16, and theslag slurry outlet 12 of two-stage precipitation groove 8 is connected with theslag slurry inlet 14 ofslag stock tank 13, theslurries outlet 3 of pre-deepgouge 1 and 5 of the slurry inlet of one-level stillpot 4 are connected with the first slush pump 22, theslurries outlet 21 ofaccident slurry tank 19 and 18 of the accident slurry inlet of one-level stillpot 4 are connected withaccident slush pump 23, be provided with automatic flow rate adjusting device and regulate the slurries amount that enters one-level stillpot 4 on the export pipeline of the first slush pump 22 andaccident slush pump 23, theslurries outlet 7 of one-level stillpot 4 and 10 of the slurry inlet of two-stage precipitation groove 8 are connected with thesecond slush pump 24, and theslag slurry outlet 16 ofslag stock tank 13 is provided withslag stock pump 25.

Wherein, one-level stillpot 4 tops are cylindrical shape, bottom be 45 °～65 ° cone-shaped, preferably 60 ° of bottom cone angles, be carbon steel material, by reinforced concrete support, the slurries treating capacity reaches 1000m³/ day, design pressure is normal pressure, and operating temperature is 30 ℃～70 ℃, and slurry temperature is 40 ℃～60 ℃, and dischargeable capacity is 500m³, diameter is 8000mm, overall height is 15328mm; Two-stage precipitation groove 8 tops are cylinder, and it is cone-shaped that bottom is, and are carbon steel material, and by reinforced concrete support, slag slurry treating capacity is 130m³/ time, design pressure is normal pressure, and operating temperature is 30 ℃～70 ℃, and slurry temperature is 40 ℃～60 ℃, and dischargeable capacity is 200m³, diameter is 6000mm, overall height is 11596mm.

The technological process of the said equipment is as follows:

1) pre-sedimentation: the ammonium sulfate slurries that carried lime-ash from desulphurization system enter pre-deep gouge 1, slurries carry out gravitational settling in pre-deep gouge 1, can not turn on agitator in separation process, preliminary sedimentation lime-ash, supernatant liquor by flowingfull mouth 2 from flowing into the rear final time desulphurization system oftrench 26;

2) first grade subsides: the slurries after pre-sedimentation are transported to one-level stillpot 4 fromslurries outlet 3 slurry inlet through one-level stillpot 45 of pre-deep gouge 1 with the first slush pump 22, slurries are uniformly distributed bygrout distribution device 17, slurries again carry out gravitational settling in one-level stillpot 4, the slurries time of staying is 11～13 hours, preferably 12 hours, thereby the lime-ash in slurries sinks to the bottom of one-level stillpot 4, clear liquid flows into absorption tower or trench certainly by the flowingfull mouth 6 on one-level stillpot 4 tops or the purifiedliquor outlet 27 of bottom; As standby, slurries also can be transported to its outlet of slurries fromaccident slurry tank 19 21 one-level stillpot 4 throughaccident slurry inlet 18 byaccident slush pump 23;

3) secondary sedimentation: the isolated slurries of first grade subsides are transported to two-stage precipitation groove 8 fromslurries outlet 7 slurry inlet through two-stage precipitation groove 8 10 of one-level stillpot 4 with thesecond slush pump 24, for reduce slag slurry is taken away ammonium sulfate and causes damage, from filler 11, add a certain amount of water to be washed to reduce the sulphur ammonium content the slag slurry, limit adds waterside and stirs, and then the abundant sedimentation of slurries after washing is further separated to lime-ash, preferably 8～10 hours sedimentation time, clear liquid flows back to desulphurization system certainly by flowingfull mouth 9 or the purified liquor outlet of two-stage precipitation groove 8, isolate bottom slag slurry, wherein, make after secondary settlement the quality percentage composition of ammonium sulfate≤6% in the slag slurry of bottom by controlling washing times and amount of water, according to circumstances can be divided into 2-3 washing, the water yield at every turn added can be added for 1:1 by fresh water (FW) and concentrate volume ratio.

4) three grades of sedimentations: theslag stock tank 13 of the slag slurry that the secondary sedimentation separation is gone out below theslag slurry outlet 12 of two-stage precipitation groove 8 is put into,slag stock tank 13 has the effect of further precipitate and separate, make the slag slurry further concentrated, the Separation of Water on top flows into from the flowingfull mouth 15 ofslag stock tank 13 melt pit that trench is pooled to absorption tower zone, send absorption tower system back to by sump pump, simultaneously, withslag stock pump 25, the slurry of the slag inslag stock tank 13 being delivered to sintering mixer allocates into by a certain percentage in raw materials for sintering or directly delivers to the iron charge field.

In this technique, the clear liquid of process sedimentation overflows back absorption tower, and the slurries that contain lime-ash are constantly concentrated, and formation is settled down to the slag of bottom and starches, and slag is starched the final slag stock tank that certainly flow to, and collects removal, thereby reaches the purpose of separation lime-ash.In this technique, slurries are actual the process of sedimentation separation gradually four times, that is: 1) in existing pre-deep gouge 1 oraccident slurry tank 19, carry out pre-sedimentation, 2) send into one-level stillpot 4 and carry out sedimentation for the second time (for main infall process), 3) carry out sedimentation for the third time after sending into two-stage precipitation groove 8,4) after the slag slurry enters concreteslag stock tank 13, also has last sedimentation, this technique makes lime-ash clearance in ammonia process of desulfurization slurries reach more than 90%, and the ammonium sulfate loss is little, and the slag slurry is moisture low; Adopt automatic control mode, simple to operate, reduced cost of labor.

Claims (8)

1. in ammonia process of desulfurization slurries, lime-ash is removed technique, comprises the following steps:

1) pre-sedimentation: ammonia process of desulfurization slurries are carried out to gravitational settling, preliminary sedimentation lime-ash, the supernatant liquor flowing full returns desulphurization system;

2) first grade subsides: the slurries after pre-sedimentation are carried out to gravitational settling again, and hydraulic detention time is 11～13 hours, further sedimentation lime-ash, and the supernatant liquor flowing full returns desulphurization system;

3) secondary sedimentation: the slurries after first grade subsides are added to water and washed, then the abundant sedimentation of slurries after washing is further separated to lime-ash, the sedimentation time is 8～10 hours, and the supernatant liquor flowing full returns desulphurization system, isolates bottom slag slurry;

4) three grades of sedimentations: the bottom slag slurry after the secondary sedimentation is carried out to gravitational settling again, and the supernatant liquor flowing full returns desulphurization system, isolates bottom ashe and is removed.

2. in ammonia process of desulfurization slurries according to claim 1, lime-ash is removed technique, it is characterized in that: in described step 3), by controlling washing times and amount of water, make after secondary settlement the quality percentage composition of ammonium sulfate≤6% in the slag slurry of bottom.

3. in ammonia process of desulfurization slurries according to claim 1 and 2, lime-ash is removed technique, and it is characterized in that: described step 2), operating temperature is 30～70 ℃, and slurry temperature is 40～60 ℃.

4. in ammonia process of desulfurization slurries according to claim 1 and 2, lime-ash is removed technique, and it is characterized in that: in described step 3), operating temperature is 30～70 ℃, and slurry temperature is 40～60 ℃.

5. one kind for realizing lime-ash eliminating equipment in ammonia process of desulfurization slurries that the described technique of claim 1 designs, comprise pre-deep gouge (1), one-level stillpot (4), two-stage precipitation groove (8), and slag stock tank (13), it is characterized in that: described pre-deep gouge (1) is provided with flowing full mouth (2) and slurries outlets (3), described one-level stillpot (4) top is respectively equipped with slurry inlet (5) and flowing full mouth (6), described one-level stillpot (4) bottom is provided with slurries outlets (7), the slurries outlets (3) of described pre-deep gouge (1) are connected with the slurry inlet (5) of described one-level stillpot (4), described two-stage precipitation groove (8) top is respectively equipped with flowing full mouth (9), slurry inlet (10), and filler (11), the bottom of described two-stage precipitation groove (8) is provided with slag slurry outlet (12), the slurries outlets (7) of described one-level stillpot (4) are connected with the slurry inlet (10) of described two-stage precipitation groove (8), described slag stock tank (13) top is respectively equipped with slag slurry inlet (14) and flowing full mouth (15), described slag stock tank (13) bottom is provided with slag slurry outlet (16), the slag slurry outlet (12) of described two-stage precipitation groove (8) is connected with the slag slurry inlet (14) of described slag stock tank (13).

6. lime-ash eliminating equipment in ammonia process of desulfurization slurries according to claim 5, it is characterized in that: described one-level stillpot (4) top is cylindrical shape, bottom be 45 °～65 ° cone-shaped, be provided with grout distribution device (17) in described one-level stillpot (4), liquid level gauge, and thermometer.

7. according to lime-ash eliminating equipment in the described ammonia process of desulfurization slurries of claim 5 or 6, it is characterized in that: described one-level stillpot (4) is provided with accident slurry inlet (18), described one-level stillpot (4) is connected with accident slurry tank (19), be respectively equipped with flowing full mouth (20) and slurries outlets (21) on described accident slurry tank (19), the slurries outlets (21) on described accident slurry tank (19) are connected with the accident slurry inlet (18) of described one-level stillpot (4).

8. according to lime-ash eliminating equipment in the described ammonia process of desulfurization slurries of claim 5 or 6, it is characterized in that: between the slurries outlets (3) of described pre-deep gouge (1) and the slurry inlet (5) of described one-level stillpot (4), be connected with the first slush pump (22), be connected with accident slush pump (23) between the slurries outlets (21) of described accident slurry tank (19) and the accident slurry inlet (18) of described one-level stillpot (4), be connected with the second slush pump (24) between the slurries outlets (7) of described one-level stillpot (4) and the slurry inlet (10) of described two-stage precipitation groove (8), the slag slurry outlet (16) of described slag stock tank (13) is provided with slag stock pump (25).

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