CN113845263A - Equipment and process for reducing ammonia nitrogen index of coal gasification water system - Google Patents
Equipment and process for reducing ammonia nitrogen index of coal gasification water system Download PDFInfo
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Abstract
The invention relates to a device and a process for reducing ammonia nitrogen indexes of a coal gasification water system, wherein a graded split steam stripping method is adopted, steam stripping is firstly carried out on high ammonia nitrogen non-hardness condensate, the condensate after steam stripping is mixed with high hardness grey water, the ammonia nitrogen indexes of the whole coal gasification water system are reduced, the situation that the steam stripping system utilizes alkali liquor to reduce the hardness and acid liquor to reversely adjust the pH value is avoided, and the operation cost and the investment of the whole gasification device are greatly reduced; meanwhile, the condensate temperature fractions generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator enter the stripping tower to be stripped and deaminated, so that the consumption of low-pressure steam and the amount of discharged wastewater are reduced; finally, the ammonia nitrogen of the low-pressure grey water pipeline is reduced, the alkaline environment is improved, and the scaling rate is slowed down by nesting the grey water flash evaporation system by using the stripping process.
Description
Technical Field
The invention relates to equipment and a process for reducing ammonia nitrogen indexes of a coal gasification water system.
Background
For the coal gasification wastewater discharged outside, if the ammonia nitrogen value exceeds the acceptable index of a downstream sewage treatment device, the pretreatment for removing ammonia nitrogen is needed for the coal gasification wastewater. However, the total hardness of the gasification wastewater is high and can generally reach 1000mg/L, and if the gasification wastewater is not subjected to hardness removal treatment, the stripping device can be seriously scaled, and the normal operation of equipment is influenced.
The existing coal gasification wastewater pretreatment device mostly adopts chemical hardness removal treatment, is limited to the limitation of solubility balance, and is unlikely to reduce the total hardness in wastewater to be very low, at most to the calcium and magnesium ion concentration with balanced solubility corresponding to the temperature of the wastewater, a steam stripping device is unavoidable and can generate scaling, and the continuous operation period is difficult to ensure. Firstly, alkali liquor chemical agents are used for hardness removal, then stripping deamination is used, waste water is subjected to deamination, and then an outlet pipeline is subjected to reverse adjustment by acid liquor so as to adapt to a proper pH value, so that the measures lead to large acid and alkali consumption, high operation cost and salt content increase of a downstream sewage treatment device. In addition, the higher the ammonia nitrogen index in the coal gasification water system is, the more likely the scaling tendency of the low-pressure grey water pipeline is caused, the flow capacity of the low-pressure grey water pipeline is reduced, and the long-period full-load operation of the coal gasification device is influenced.
The coal water slurry or pulverized coal gasification black water flash evaporation system mainly functions in recovering waste heat of black water and adjusting the amount of discharged water according to the content of ammonia nitrogen and chloride ions in a coal gasification water system. Because the waste water has the characteristics of high hardness and high ammonia nitrogen, the waste water can enter the stripping tower for deamination after the hardness of the waste water is reduced by alkali liquor, otherwise the waste water blocks the tower tray to influence the normal operation of the device.
Prior applications with publication numbers CN102531260A and CN103964631A disclose a stripping process for high concentration ammonia nitrogen wastewater using NaOH solution or Ca (OH)2The solution reduces the total hardness of the wastewater entering the stripping tower, and the wastewater after stripping deamination is adjusted to pH 6-9 by acid liquor and then enters a biochemical treatment unit. The main disadvantage of this method is that the pH value of the waste water is adjusted to above 11 by using alkali liquor, and the pH value of the waste water needs to be adjusted back to about 9 by using hydrochloric acid again in consideration of the acceptable pH value range of the downstream waste water treatment device. Therefore, the addition of acid and alkali not only increases the operation cost, but also increases the flow rate and the TDS content of the discharged wastewater. In addition, the gasification waste water entering the system is sent from the gasification grey water treatment system after coagulation and precipitation, and not only contains a certain amount of suspended matters, but also contains calcium and magnesium ions. It is clear that its calcium magnesium ion and its product with the ion concentration of the anion forming the precipitate equals the solubility product constant at this temperature. At this time, the calcium and magnesium ion concentration is the saturation concentration. Therefore, the stripping tower of the device is inevitably subjected to scaling, and the long-period stable operation of the stripping tower is influenced.
The prior application with publication number CN209922936U discloses a coal gasification black water flash evaporation treatment system, in which high ammonia nitrogen ash water generated by a first gas-liquid separation tank, a second gas-liquid separation tank and a third gas-liquid separation tank and high hardness ash water of a third flash tank are directly mixed and then returned to a coal gasification water system. The method has the main defect that the wastewater with high hardness and high ammonia nitrogen is directly discharged and can be accepted only after the ammonia nitrogen index is qualified after the pretreatment. Therefore, the hardness reduction and deamination treatment is needed, and in addition, the high ammonia nitrogen grey water and the high hardness grey water are directly mixed without treatment, so that the relative pipelines and equipment in the coal gasification water system are seriously scaled, and the long-term operation of the device is influenced. Finally, the measure also deteriorates the environment of the whole coal gasification water system and increases the amount of wastewater discharged.
After the grey water is subjected to flash evaporation and heat recovery, the condensate rich in ammonia nitrogen is directly mixed with the high-hardness condensate of the vacuum flash evaporator, and then a strand of discharged wastewater is pumped out and sent to the whole plant for sewage treatment. The discharged wastewater has the characteristics of high hardness and high ammonia nitrogen, so that chemical agents are required to be used for removing hardness, then stripping deamination is carried out, and finally acid liquor is used for reverse adjustment.
However, the existing treatment mode generally has the following problems:
(1) chemical agents such as alkali liquor are directly utilized for hardness removal, so that firstly, the alkali liquor consumption is large, and the operation cost is increased; secondly, the occupied area and investment of related hardware removing equipment are increased; thirdly, finally, alkali liquor enters the wastewater, and the treatment load of the discharged wastewater is increased; fourthly, firstly, alkali liquor is utilized to remove hardness, so that a wastewater system presents an alkaline environment, and is limited by solubility balance, scaling tendency inevitably exists in a stripping tower along with the change of temperature, and the long-period full-load operation of the device and the stability of water outlet indexes are influenced;
(2) firstly, after the hardness of the wastewater is removed by using alkali liquor, the pH value needs to be raised to about 12, the pH value is limited by the acceptable pH value index of downstream sewage treatment, and the pH value of a wastewater system needs to be reversely adjusted to about 9 by using acid liquor. Finally, the salt content in the index of the outgoing wastewater is increased, and the treatment load of a high-salt-content crystallization device is influenced;
(3) in order to ensure the stability of wastewater indexes received by downstream sewage treatment, a coal gasification wastewater pretreatment device usually needs to be provided with a standby series. When the run train needs cleaning due to fouling, the standby train needs to be put into operation immediately. The problem that the normal operation of the downstream sewage treatment device is influenced by the fluctuation of the wastewater indexes received by the downstream sewage treatment device is avoided.
Disclosure of Invention
The invention aims to solve the technical problem of providing equipment and a process for reducing the ammonia nitrogen index of a coal gasification water system aiming at the current situation of the prior art, and the equipment and the process can delay the scaling rate and reduce the amount of discharged wastewater, thereby effectively ensuring the steam stripping effect and the period, avoiding the consumption of acid and alkali liquor and reducing the operation cost of a device.
The technical scheme adopted by the invention for solving the technical problems is as follows:
an equipment for reducing ammonia nitrogen index of a coal gasification water system comprises:
the high-pressure evaporation hot water tower is used for carrying out high-pressure flash evaporation and heat recovery on the materials;
the input end of the acid gas condenser is connected with the top of the high-pressure evaporation hot water tower;
the feed end of the acid-gas separator is connected with the output end of the acid-gas condenser, the top of the acid-gas separator is provided with a first output end for outputting acid gas, and the bottom of the acid-gas separator is provided with a second output end for outputting a liquid phase;
the low-pressure evaporation hot water tower is connected with a liquid phase output port at the bottom of the high-pressure evaporation hot water tower and is used for carrying out low-pressure flash evaporation on materials;
the feed inlet of the low-pressure flash condenser is connected with the top of the low-pressure evaporation hot water tower;
the input port of the low-pressure flash separator is connected with the discharge port of the low-pressure flash condenser, the top of the low-pressure flash separator is provided with a first output port for outputting acid gas, and the bottom of the low-pressure flash separator is provided with a second output port for outputting liquid phase;
the material inlet of the vacuum flash separator is connected with the liquid phase discharge hole at the bottom of the low-pressure evaporation hot water tower and is used for carrying out vacuum flash evaporation on the materials;
the inlet of the vacuum flash evaporation condenser is connected with the top of the vacuum flash evaporation separator;
a material inlet of the vacuum flash separator is connected with an outlet of the vacuum flash condenser, a first material outlet for outputting acid gas is arranged at the top of the vacuum flash separator, and a second material outlet for outputting a liquid phase is arranged at the bottom of the vacuum flash separator;
the top of the No. 1 settling tank is connected with a second output port of the low-pressure flash separator and a second material outlet of the vacuum flash separator;
the stripping tower is provided with a first input port connected with a second output end of the acid-gas separator and a second input port connected with the bottom of the No. 1 settling tank, the top of the stripping tower is provided with a pipeline for outputting ammonia-containing gas, and the bottom of the stripping tower is provided with an outlet for outputting a liquid phase;
and the bottom of the 2# settling tank is connected with the bottom of the vacuum flash separator and the outlet of the stripping tower.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a condensate purification heat exchanger, and is used for exchanging heat for the material conveyed to the stripping tower from the bottom of the No. 1 settling tank.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a grey water lifting pump which is used for pumping the materials which are conveyed to the stripping tower from the bottom of the 1# settling tank.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a water cooler which is used for cooling the liquid phase which is conveyed to the 2# settling tank from the outlet of the stripping tower.
In the invention, the high-pressure evaporation hot water tower comprises a lower tower and an upper tower which are connected with each other, wherein the lower tower is used for receiving black water from the gasification furnace and the washing tower and carrying out flash evaporation on the black water, and the upper tower is used for preheating a gas phase flashed from the lower tower.
A process for reducing ammonia nitrogen indexes of a coal gasification water system comprises the following steps:
black water from a gasification furnace and a washing tower is decompressed to 1.1-1.4 MPaG and then enters a lower tower of a high-pressure evaporation hot water tower, and a gas phase flashed off is sent to an upper tower of the high-pressure evaporation hot water tower through a pipeline to preheat low-temperature grey water; the method comprises the following steps that after sufficient mass transfer and heat transfer are carried out on flash evaporation gas, the flash evaporation gas enters an acid gas condenser to be cooled to 90-100 ℃, then the flash evaporation gas is separated by an acid gas separator, the gas phase is sent to an acid gas system, and the liquid phase is sent to a stripping tower;
the liquid phase in the lower tower of the high-pressure evaporation hot water tower is decompressed to 0.2-0.3 MPaG, enters the low-pressure evaporation hot water tower, the gas phase flashed out enters a low-pressure flash evaporation condenser to be cooled to 60-80 ℃, is separated by a low-pressure flash evaporation separator and is merged into an acid gas system; the liquid phase of the lower tower of the low-pressure evaporation hot water tower is decompressed to-0.05 to-0.07 MPaG, enters a vacuum flash separator, the gas phase after flash evaporation enters a vacuum flash condenser to be cooled to 60 to 80 ℃, is separated by the vacuum flash separator and then is sent to a subsequent water ring vacuum pump system;
the liquid phase separated by the acid gas separator directly enters a first tray of a stripping tower, the liquid phase generated by the low-pressure flash separator and the vacuum flash separator is sent to a No. 1 settling tank for liquid-solid separation, then is pressurized to 0.4-0.5 MPaG by an ash water lifting pump, exchanges heat with the purified condensate at the bottom of the stripping tower by a purified condensate heat exchanger to 100-110 ℃, and is sent to the stripping tower, and the purified condensate at the bottom of the stripping tower after heat exchange is cooled by a water cooler and then is sent to the No. 2 settling tank.
The process optimizes the technological processes of grey water flash evaporation and steam stripping, selects a proper grey water part for steam stripping, and reduces the scaling rate of a coal gasification water system and the operation cost of a steam stripping system; the optimized steam stripping process flow has less investment, can solve the problem of scaling which generally exists at present, and obviously improves the economic benefit and the safety of the whole device. The method can avoid setting a hardness removal facility, reduce the ammonia nitrogen index in the coal gasification water system, delay the scaling rate and reduce the amount of discharged wastewater. Meanwhile, the scale formation influence of calcium and magnesium ions can be effectively avoided, and the steam stripping effect and period are effectively guaranteed. Finally, the process also avoids the consumption of acid and alkali liquor and reduces the operation cost of the device.
The condensate generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator is subjected to sedimentation separation to remove part of dust and then is subjected to stripping deamination, so that the tower tray of the stripping tower can be prevented from being blocked; the condensate generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator is not mixed with the condensate of the vacuum flash evaporator and is treated by a stripping tower, the gas phase at the top of the stripping tower can recover ammonia, and the purified condensate at the bottom of the stripping tower returns to an ash water tank; the condensed liquid generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator enters the stripping tower in a graded and split manner according to the temperature, the temperature positions of respective condensed liquid are fully utilized, and the steam consumption and the specification size of heat exchange equipment are reduced; the invention is not only suitable for the condensate generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator, but also can be used for the condensate generated by the high-pressure flash tower, the low-pressure flash tower and the vacuum flash tower and the pulverized coal gasification process.
Compared with the prior art, the invention has the advantages that: the invention adopts a staged split steam stripping method, firstly steam stripping is carried out on the high ammonia nitrogen non-hardness condensate, the steam stripped condensate is mixed with the high hardness grey water, the ammonia nitrogen index of the whole coal gasification water system is reduced, the condition that the steam stripping system utilizes alkali liquor to reduce the hardness and acid liquor to reversely adjust the pH value is avoided, and the operation cost and the investment of the whole gasification device are greatly reduced; meanwhile, the condensate temperature fractions generated by the high-pressure evaporation hot water tower, the low-pressure evaporation hot water tower and the vacuum flash separator enter the stripping tower to be stripped and deaminated, so that the consumption of low-pressure steam and the amount of discharged wastewater are reduced; finally, the ammonia nitrogen of the low-pressure grey water pipeline is reduced, the alkaline environment is improved, and the scaling rate is slowed down by nesting the grey water flash evaporation system by using the stripping process.
Drawings
FIG. 1 is a flow chart of an apparatus according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
As shown in FIG. 1, the apparatus for reducing ammonia nitrogen index of a coal gasification water system in the embodiment comprises:
the high-pressure evaporation hot water tower 1 is used for carrying out high-pressure flash evaporation on the materials;
the input end of the acid gas condenser 10 is connected with the top of the high-pressure evaporation hot water tower 1;
the feed end of the acid-gas separator 5 is connected with the output end of the acid-gas condenser 10, the top of the acid-gas separator 5 is provided with a first output end for outputting acid gas, and the bottom of the acid-gas separator 5 is provided with a second output end for outputting liquid phase;
the low-pressure evaporation hot water tower 2 is connected with a liquid phase output port at the bottom of the high-pressure evaporation hot water tower 1 and is used for carrying out low-pressure flash evaporation on materials;
a feed inlet of the low-pressure flash condenser 11 is connected with the top of the low-pressure evaporation hot water tower 2;
the input port of the low-pressure flash separator 6 is connected with the discharge port of the low-pressure flash condenser 11, the top of the low-pressure flash separator 6 is provided with a first output port for outputting acid gas, and the bottom of the low-pressure flash separator 6 is provided with a second output port for outputting liquid phase;
a material inlet of the vacuum flash separator 3 is connected with a liquid phase discharge hole at the bottom of the low-pressure evaporation hot water tower 2 and is used for carrying out vacuum flash evaporation on the materials;
a vacuum flash condenser 12, the inlet of which is connected with the top of the vacuum flash separator 3;
a material inlet of the vacuum flash separator 7 is connected with an outlet of the vacuum flash condenser 12, a first material outlet for outputting acid gas is arranged at the top of the vacuum flash separator 7, and a second material outlet for outputting a liquid phase is arranged at the bottom of the vacuum flash separator 7;
the top of the No. 1 settling tank 8 is connected with the second output port of the low-pressure flash separator 6 and the second material outlet of the vacuum flash separator 7;
the stripping tower 4 is provided with a first input port connected with a second output end of the acid-gas separator 5 and a second input port connected with the bottom of the No. 1 settling tank 8, the top of the stripping tower is provided with a pipeline for outputting ammonia-containing gas, and the bottom of the stripping tower is provided with an outlet for outputting liquid phase;
and the bottom of the 2# settling tank 9 is connected with the bottom of the vacuum flash separator 3 and the outlet of the stripping tower 4.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a condensate purification heat exchanger 14 which is used for exchanging heat for the material conveyed to the stripping tower 4 from the bottom of the 1# settling tank 8.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a grey water lifting pump 15 which is used for pumping the materials which are conveyed to the stripping tower 4 from the bottom of the 1# settling tank 8.
The equipment for reducing the ammonia nitrogen index of the coal gasification water system also comprises a water cooler 13 which is used for cooling the liquid phase which is output from the outlet of the stripping tower 4 to the 2# settling tank 9.
The high-pressure evaporation hot water tower 1 comprises a lower tower and an upper tower which are connected with each other, wherein the lower tower is used for receiving black water from the gasification furnace and the washing tower and carrying out flash evaporation on the black water, and the upper tower is used for preheating a gas phase flashed from the lower tower.
The invention discloses a process for reducing ammonia nitrogen indexes of a coal gasification water system, which comprises the following steps:
reducing the pressure of black water from a gasification furnace and a washing tower to 1.1-1.4 MPaG, entering a lower tower of a high-pressure evaporation hot water tower 1, sending a gas phase flashed off into an upper tower of the high-pressure evaporation hot water tower 1 through a pipeline, and preheating low-temperature grey water; after sufficient mass transfer and heat transfer, the flash evaporation gas enters an acid gas condenser 10 to be cooled to 90-100 ℃, and then is separated by an acid gas separator 5, the gas phase is sent to an acid gas system, and the liquid phase is sent to a stripping tower 4;
the lower tower liquid phase of the high-pressure evaporation hot water tower 1 is decompressed to 0.2-0.3 MPaG, enters the low-pressure evaporation hot water tower 2, the gas phase flashed off enters a low-pressure flash evaporation condenser 12 to be cooled to 60-80 ℃, is separated by a low-pressure flash evaporation separator 6 and is then merged into an acid gas system; the liquid phase of the lower tower of the low-pressure evaporation hot water tower 2 is decompressed to-0.05 to-0.07 MPaG, enters a vacuum flash separator 3, the gas phase after flash evaporation enters a vacuum flash condenser 13 to be cooled to 60 to 80 ℃, is separated by a vacuum flash separator 7 and then is sent to a subsequent water ring vacuum pump system;
the liquid phase separated by the acid gas separator 5 directly enters a first tower tray of the stripping tower 4, the liquid phase generated by the low-pressure flash separator 6 and the vacuum flash separator 7 is sent to a No. 1 settling tank 8 for liquid-solid separation, the liquid phase is pressurized to 0.4-0.5 MPaG by using an ash water lifting pump 15 and then exchanges heat with the purified condensate at the bottom of the stripping tower 4 by using a purified condensate heat exchanger 14 to 100-110 ℃, and the purified condensate at the bottom of the stripping tower after heat exchange is sent to a No. 2 settling tank 9 after being cooled by a water cooler 13.
In the embodiment, 2000t/d of coal input in a single furnace day is taken as an example, and a corresponding single-series grey water flash evaporation system is taken as a calculation reference. Black water from a gasification furnace and a washing tower firstly passes through a high-pressure flash tower, a low-pressure flash tower and a vacuum flash tower to recover heat in the black water and then enters a 2# settling tank for liquid-solid separation, gas phase of flash evaporation of each stage of flash tower is subjected to heat recovery, liquid phase of flash evaporation enters a stripping tower in different stages for stripping deamination, and ammonia nitrogen indexes in purified condensate at the outlet of the stripping tower can be flexibly adjusted by controlling the flow of low-pressure steam.
| Ash water flash evaporation process | Conventional process | The stripping process of the invention |
| Ammonia nitrogen index mg/L of water system | 350～600 | 10～50 |
| Low pressure steam consumption kg/h | 14000 | 8000 |
| Sodium hydroxide consumption kg/h | 1446 | 0 |
| Consumption of sodium carbonate kg/h | 0 | 0 |
| Cost of chemicals consumption ten thousand yuan/a | 580 | 0 |
As can be seen from the above table: if the conventional sodium hydroxide solution is adopted for precipitation and pH value adjustment, the consumed alkali liquor is more and reaches 1446kg/h, and the cost of the sodium hydroxide solution consumed every year is 580 ten thousand yuan. The stripping process adopted by the embodiment reduces the ammonia nitrogen index in the grey water system, avoids the consumption of sodium hydroxide and reduces the consumption cost of chemicals. Moreover, the concentration of calcium and magnesium ions in the flash evaporation gas condensate treated by the steam stripping process is low, and the temperature is avoidedBecomeThe scale of the stripping tower and related pipelines during chemical reaction greatly prolongs the operation period of the stripping system, improves the environment of low-pressure grey water pipelines in a coal gasification water system, reduces the scale of the pipelines, and achieves the aim of improving the long-period stable full-load operation of the device. In addition, the amount of discharged wastewater can be reduced according to the ion concentration of a low-pressure grey water system which is actually operated on site, and the load of a downstream sewage treatment system is also reduced. Obviously, the invention reduces the consumption cost of chemicals, improves the economic benefit of the device and prolongs the operation period of the device.
Claims (6)
1. The utility model provides a reduce equipment of coal gasification water system ammonia nitrogen index which characterized in that includes:
the high-pressure evaporation hot water tower is used for carrying out high-pressure flash evaporation and heat recovery on the materials;
the input end of the acid gas condenser is connected with the top of the high-pressure evaporation hot water tower;
the feed end of the acid-gas separator is connected with the output end of the acid-gas condenser, the top of the acid-gas separator is provided with a first output end for outputting acid gas, and the bottom of the acid-gas separator is provided with a second output end for outputting a liquid phase;
the low-pressure evaporation hot water tower is connected with a liquid phase output port at the bottom of the high-pressure evaporation hot water tower and is used for carrying out low-pressure flash evaporation on materials;
the feed inlet of the low-pressure flash condenser is connected with the top of the low-pressure evaporation hot water tower;
the input port of the low-pressure flash separator is connected with the discharge port of the low-pressure flash condenser, the top of the low-pressure flash separator is provided with a first output port for outputting acid gas, and the bottom of the low-pressure flash separator is provided with a second output port for outputting liquid phase;
the material inlet of the vacuum flash separator is connected with the liquid phase discharge hole at the bottom of the low-pressure evaporation hot water tower and is used for carrying out vacuum flash evaporation on the materials;
the inlet of the vacuum flash evaporation condenser is connected with the top of the vacuum flash evaporation separator;
a material inlet of the vacuum flash separator is connected with an outlet of the vacuum flash condenser, a first material outlet for outputting acid gas is arranged at the top of the vacuum flash separator, and a second material outlet for outputting a liquid phase is arranged at the bottom of the vacuum flash separator;
the top of the No. 1 settling tank is connected with a second output port of the low-pressure flash separator and a second material outlet of the vacuum flash separator;
the stripping tower is provided with a first input port connected with a second output end of the acid-gas separator and a second input port connected with the bottom of the No. 1 settling tank, the top of the stripping tower is provided with a pipeline for outputting ammonia-containing gas, and the bottom of the stripping tower is provided with an outlet for outputting a liquid phase;
and the bottom of the 2# settling tank is connected with the bottom of the vacuum flash separator and the outlet of the stripping tower.
2. The equipment for reducing the ammonia nitrogen index of the coal gasification water system according to claim 1, is characterized in that: still include and purify the condensate heat exchanger for carry out the heat transfer to the material of 1# settling tank bottom defeated stripper.
3. The equipment for reducing the ammonia nitrogen index of the coal gasification water system according to claim 2 is characterized in that: the system also comprises a grey water lifting pump which is used for pumping the materials which are conveyed to the stripping tower from the bottom of the No. 1 settling tank.
4. The equipment for reducing the ammonia nitrogen index of the coal gasification water system according to claim 1, is characterized in that: the device also comprises a water cooler which is used for cooling the liquid phase which is output to the 2# settling tank from the outlet of the stripping tower.
5. The equipment for reducing the ammonia nitrogen index of the coal gasification water system according to claim 1, 2, 3 or 4, is characterized in that: the high-pressure evaporation hot water tower comprises a lower tower and an upper tower which are connected with each other, wherein the lower tower is used for receiving black water from the gasification furnace and the washing tower and carrying out flash evaporation on the black water, and the upper tower is used for preheating a gas phase flashed from the lower tower.
6. A process for reducing ammonia nitrogen indexes of a coal gasification water system is characterized by comprising the following steps:
black water from a gasification furnace and a washing tower is decompressed to 1.1-1.4 MPaG and then enters a lower tower of a high-pressure evaporation hot water tower, and a gas phase flashed off is sent to an upper tower of the high-pressure evaporation hot water tower through a pipeline to preheat low-temperature grey water; the method comprises the following steps that after sufficient mass transfer and heat transfer are carried out on flash evaporation gas, the flash evaporation gas enters an acid gas condenser to be cooled to 90-100 ℃, then the flash evaporation gas is separated by an acid gas separator, the gas phase is sent to an acid gas system, and the liquid phase is sent to a stripping tower;
the liquid phase in the lower tower of the high-pressure evaporation hot water tower is decompressed to 0.2-0.3 MPaG, enters the low-pressure evaporation hot water tower, the gas phase flashed out enters a low-pressure flash evaporation condenser to be cooled to 60-80 ℃, is separated by a low-pressure flash evaporation separator and is merged into an acid gas system; the liquid phase of the lower tower of the low-pressure evaporation hot water tower is decompressed to-0.05 to-0.07 MPaG, enters a vacuum flash separator, the gas phase after flash evaporation enters a vacuum flash condenser to be cooled to 60 to 80 ℃, is separated by the vacuum flash separator and then is sent to a subsequent water ring vacuum pump system;
the liquid phase separated by the acid gas separator directly enters a first tray of a stripping tower, the liquid phase generated by the low-pressure flash separator and the vacuum flash separator is sent to a No. 1 settling tank for liquid-solid separation, then is pressurized to 0.4-0.5 MPaG by an ash water lifting pump, exchanges heat with the purified condensate at the bottom of the stripping tower by a purified condensate heat exchanger to 100-110 ℃, and is sent to the stripping tower, and the purified condensate at the bottom of the stripping tower after heat exchange is cooled by a water cooler and then is sent to the No. 2 settling tank.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114921269A (en) * | 2022-06-09 | 2022-08-19 | 蒲城清洁能源化工有限责任公司 | Process for reducing ammonia nitrogen in methanol prepared from coal |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114921269A (en) * | 2022-06-09 | 2022-08-19 | 蒲城清洁能源化工有限责任公司 | Process for reducing ammonia nitrogen in methanol prepared from coal |
| CN114921269B (en) * | 2022-06-09 | 2023-10-27 | 蒲城清洁能源化工有限责任公司 | Ammonia nitrogen reducing process for coal-to-methanol |
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