Process and system for recovering ammonia from the condensate stripping unit of the low temperature conversion process

Abstract

The present invention provides a process and system for recovering ammonia from a condensate stripping unit of a low-temperature conversion process. The process for recovering ammonia from a condensate stripping unit of a low-temperature conversion process comprises the following steps: optimizing and adjusting the originally designed stripping process so that the stripping gas directly enters the ammonia absorption tower of the phosphate ammonium unit, the acidic gas after ammonia washing is sent back to the originally designed sulfur recovery section, the phosphate ammonium rich liquid enters the desorption tower after heat exchange and deacidification, and the ammonia gas at the top of the desorption tower is condensed and cooled to obtain high-quality ammonia water. The present invention also discloses a system for recovering ammonia from a condensate stripping unit of a low-temperature conversion process, including an ammonia absorption tower and a deacidification tower. The present invention can obtain S based on the full utilization of the originally designed stripping process. 2‑ The characterized high-quality ammonia water has an acid component content of less than 3ppm. In addition, the ammonia content in the acid gas at the top outlet of the ammonia absorption tower is 0-10ppm, and the acid gas pressure at the top outlet of the ammonia absorption tower is not less than 0.1MPa(G).

Description

Technical Field

[0001] The present invention relates to a technology for recovering ammonia from a low-temperature conversion process condensate stripping process, and in particular to a process and system for recovering ammonia from a low-temperature conversion process condensate stripping unit. Background Art

[0002] At present, the domestic coal chemical industry and refining industry mostly use single-tower stripping or double-tower gas or side-line single stripping tower technology to strip the conversion low-temperature process condensate containing components such as ammonia, hydrogen sulfide, and carbon dioxide.

[0003] During actual operation, the above-mentioned stripping process cannot achieve accurate separation of ammonia from components such as hydrogen sulfide and carbon dioxide in the low-temperature process condensate, resulting in a high ammonia content in the acid gas, affecting the operation of the sulfur recovery section. The ammonia water has a high hydrogen sulfide content and cannot be used as a raw material for desulfurization and denitrification. Summary of the invention

[0004] The object of the present invention is to propose a process for recovering ammonia from a condensate stripping unit of a low-temperature process in order to solve the problems of high ammonia content in acid gas and high sulfur content in ammonia water in a single-tower stripping or double-tower gas or a side-line single stripping tower. The process uses the stripping gas of the original designed stripping process after optimization and adjustment as a raw material, adopts the phosphate ammonium process to strengthen the separation and recovery of ammonia therein, so that the ammonia content in the acid gas at the outlet of the ammonia absorption tower after washing ammonia is controlled at 0-10 ppm, and the pressure is not less than 0.1 MPa (G). By strengthening the deacidification of the phosphate ammonium rich liquid, the high-quality ammonia water obtained by desorption is concentrated in the form of S 2- The characterized acidic component content is less than 3ppm. This not only solves a series of problems including environmental protection caused by the difficulty in using ammonia water produced by the stripping method, but also realizes the comprehensive utilization of ammonia resources.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a process for recovering ammonia from a stripping unit of a condensate in a low-temperature conversion process, comprising the following steps: optimizing and adjusting the stripping process so that the stripping gas of the stripping unit directly enters the ammonia absorption tower of the phosphate ammonium unit, or the acid gas and separation gas of the stripping process directly enter the ammonia absorption tower of the phosphate ammonium unit, the acid gas after enhanced ammonia washing is sent to the original (existing) sulfur recovery section or the original designed flare outside the boundary area, the phosphate ammonium rich liquid enters the desorption tower after heat exchange and enhanced deacidification, and the ammonia vapor at the top of the desorption tower is condensed and cooled to obtain high-quality ammonia water, wherein the high-quality ammonia water is S 2- The characterized acid component content is less than 3ppm. In addition, the ammonia content in the acid gas at the top outlet of the ammonia absorption tower is 0-10ppm, and the acid gas pressure at the top outlet of the ammonia absorption tower is not less than 0.1MPa(G).

[0006] The acidic components in the acid gas include, but are not limited to, carbon dioxide, hydrogen sulfide, and hydrogen cyanide.

[0007] Further, the optimized adjustment of the stripping process adopts any one of the following:

[0008] When the stripping unit is a single-tower stripping unit A1, its stripping process is optimized and adjusted: the stripping tower condenser and stripping tower separator of the original design (stripping unit before transformation) are stopped; the stripping tower and condensate heat exchanger of the original design are used, and part of the fillers or plates in the tower may be replaced; when the pressure at the top of the stripping tower of the original design remains unchanged or is slightly adjusted, the feed part of the stripping tower of the original design is heat-exchanged with the bottom liquid in the condensate heat exchanger of the original design, and the remaining part is not heat-exchanged with the bottom liquid in the condensate heat exchanger of the original design, but is directly mixed with part of the feed after heat exchange, so as to adjust the feed temperature of the stripping tower of the original design, thereby changing the top temperature of the stripping tower of the original design, so that the stripping gas at the top of the stripping tower of the original design directly enters the ammonia absorption tower; the ammonia content in the bottom liquid of the stripping tower of the original design remains unchanged;

[0009] Furthermore, the possible replacement of part of the packing or tray in the tower includes replacement caused by corrosion of local packing or tray in the original design stripping tower during production practice; and replacement caused by adjusting the top temperature of the originally designed stripping tower while keeping the top pressure of the originally designed stripping tower unchanged or slightly adjusting it to ensure that the ammonia content in the bottom liquid of the originally designed stripping tower remains unchanged or to achieve a lower ammonia content in the bottom liquid of the originally designed stripping tower; or replacement caused by ensuring that the ammonia content in the bottom liquid of the originally designed stripping tower remains unchanged due to actual stripping load exceeding the originally designed stripping load, etc.

[0010] When the stripping unit is a double-tower stripping unit A2, optimize and adjust its stripping process, stop using the original design of H2S / CO2 stripping tower feed heater and H2S / CO2 stripping tower condenser and H2S / CO2 stripping tower separator, stop using the original design of ammonia stripping tower condenser and ammonia stripping tower reflux and final condenser; use the original design of H2S / CO2 stripping tower and ammonia stripping tower, and possibly replace part of the packing or tower plate in the original design of H2S / CO2 stripping tower and / or ammonia stripping tower, and add a condensate heat exchanger; in the original design of H2S / CO2 stripping tower, the original design of H2S / CO2 stripping tower and / or ammonia stripping tower are used. When the tower top pressure remains unchanged or is slightly adjusted, the feed temperature of the originally designed H2S / CO2 stripping tower is adjusted by exchanging heat between the feed part of the originally designed H2S / CO2 stripping tower and the tower bottom liquid in the newly designed condensate heat exchanger, and the remaining part does not exchange heat with the tower bottom liquid in the newly designed condensate heat exchanger, but is directly mixed with the part of the feed after heat exchange, thereby changing the top temperature of the originally designed H2S / CO2 stripping tower and allowing the stripping gas from the top of the originally designed H2S / CO2 stripping tower to directly enter the ammonia absorption tower; the ammonia content in the bottom liquid of the originally designed ammonia stripping tower remains unchanged.

[0011] Furthermore, the possible replacement of part of the packing or plates in the tower includes the replacement caused by corrosion of local packing or plates in the originally designed H2S / CO2 stripping tower and / or ammonia stripping tower during production practice; and the replacement caused by adjusting the top temperature of the originally designed stripping tower while keeping the top pressure of the originally designed H2S / CO2 stripping tower unchanged or slightly adjusting it to ensure that the ammonia content in the bottom liquid of the originally designed ammonia stripping tower remains unchanged or to achieve a lower ammonia content in the bottom liquid of the originally designed ammonia stripping tower; or the actual stripping load exceeds the originally designed stripping load, in order to ensure that the ammonia content in the bottom liquid of the originally designed ammonia stripping tower remains unchanged, etc.

[0012] The H2S / CO2 stripping tower is also called a "deacidification tower".

[0013] When the stripping unit is a side-line single stripping tower unit A3, the stripping process is optimized and adjusted, and the stripping tower separator, three-stage condenser, three-stage separator, gas ammonia refining facilities, ammonia scrubber, ammonia water cooler, first ammonia water intermediate tank, and ammonia water pump of the original design are stopped; the side-line single stripping tower, the side-line single stripping tower cold feed cooler, the first condenser, the first separator, the second condenser, the second separator, and the condensate heat exchanger of the original design are used; under the condition that the pressure and temperature of the side-line single stripping tower and the pressure of the second separator of the original design remain unchanged, the outlet temperature of the second condenser of the original design is adjusted to be 100 °C. The inlet temperature is adjusted so that the acid gas at the top of the original side-line single steam stripping tower and the separated gas at the outlet of the secondary separator are mixed and directly enter the ammonia absorption tower; the ammonia content in the bottom liquid of the original side-line single steam stripping tower remains unchanged; the top cold feed of the original side-line single steam stripping tower is changed from the original stripping wastewater to the low-temperature process condensate, and the low-temperature process condensate comes from the side-line separated liquid before mixing, which can reduce the load of the original stripping design; when the top cold feed of the original side-line single steam stripping tower uses the low-temperature process condensate from the side-line separated liquid before mixing, the original design is maintained unchanged.

[0014] Or shut down the originally designed stripping tower separator, secondary condenser, secondary separator, tertiary condenser, tertiary separator, gas ammonia refining facilities, ammonia scrubber, ammonia water cooler, first ammonia water intermediate tank, ammonia water pump; use the originally designed side line single stripping tower, side line single stripping tower cold feed cooler, primary condenser, primary separator, condensate heat exchanger; under the condition that the originally designed side line single stripping tower operating pressure and temperature and the primary condenser pressure remain unchanged, adjust the originally designed primary condenser outlet temperature to make the originally designed side line single stripping tower The top acid gas and the separated gas at the outlet of the first separator are mixed and directly enter the ammonia absorption tower; the ammonia content in the bottom liquid of the original side-line single steam stripping tower remains unchanged; the top cold feed of the original side-line single steam stripping tower is changed from the original steam stripping wastewater to the low-temperature process condensate, which comes from the side-line separation liquid before mixing, thereby reducing the load of the original steam stripping design; when the top cold feed of the original side-line single steam stripping tower uses the low-temperature process condensate from the side-line separation liquid before mixing, the original design is maintained unchanged.

[0015] Furthermore, the low-temperature conversion process condensate comes from a conversion process device in the coal chemical industry and / or the refining industry, or also includes ammonia-containing flash steam entering the stripping process.

[0016] The cryogenic process condensate includes, but is not limited to, one or more of the following components: carbon monoxide, hydrogen, carbon dioxide, nitrogen, methane, hydrogen sulfide, carbonyl sulfide, argon, ammonia, hydrogen cyanide, water, methanol, and hydrogen chloride.

[0017] The ammonia-containing high-pressure flash steam includes, but is not limited to, one or more of the following components: carbon monoxide, hydrogen, carbon dioxide, nitrogen, methane, hydrogen sulfide, carbonyl sulfide, argon, ammonia, hydrogen cyanide and water.

[0018] Furthermore, the ammonia content in the acid gas at the outlet of the ammonia absorption tower top is 0-10ppm, and the number of ammonia absorption and separation sections of the ammonia absorption tower is set according to the separation requirements of the ammonia content in the acid gas at the outlet of the ammonia absorption tower top; the more sections, the lower the ammonia content in the acid gas; generally, two sections can achieve an ammonia content in the acid gas of ≤10ppm, and when the ammonia content in the acid gas is close to 0ppm, multiple sections are required.

[0019] The stripping gas of the single-tower stripping unit A1 after optimization and adjustment directly enters the ammonia absorption tower from bottom to top, and is washed and separated by the phosphate ammonium solutions of the two ammonia absorption and separation sections respectively, and the ammonia therein is recovered, and is condensed and cooled at the same time, and the acid gas after washing ammonia is discharged from the top of the ammonia absorption tower. The ammonia absorption tower is divided into the first ammonia absorption and separation section and the second ammonia absorption and separation section from bottom to top. The stripping gas of the single-tower stripping unit A1 first enters the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the lower-stage circulating phosphate ammonium solution after cooling also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section, and the ammonia in the stripping gas of the single-tower stripping unit A1 is strengthened to absorb and separate. The stripping gas of the single-tower stripping unit A1 after washing ammonia enters the first overflow chamber of the first ammonia absorption and separation section, and then is collected by the first overflow chamber and enters the gas inlet of the second feed chamber of the second ammonia absorption and separation section. The lower-stage circulating phosphate ammonium solution after washing ammonia is discharged from the liquid outlet of the first underflow chamber of the first ammonia absorption and separation section, part of which enters the lower-stage circulation pump, and the remaining part enters the rich liquid pump. The cooled phosphate ammonium lean liquid enters the liquid inlet of the second feed chamber of the second ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas of the single-tower stripping unit A1. The acid gas after ammonia washing enters the second overflow chamber of the second ammonia absorption and separation section, and is collected from the second overflow chamber and discharged from the top of the ammonia absorption tower. The phosphate ammonium lean liquid after ammonia washing is discharged from the liquid outlet of the second bottom flow chamber of the second ammonia absorption and separation section, and enters the liquid inlet of the first bottom flow chamber of the first ammonia absorption and separation section.

[0020] The stripping gas of the double-tower stripping unit A2 after optimization and adjustment directly enters the ammonia absorption tower from bottom to top, and is washed and separated by the phosphate ammonium solution of the two ammonia absorption and separation sections respectively, and the ammonia therein is recovered, and is condensed and cooled at the same time, and the acid gas after washing ammonia is discharged from the top of the ammonia absorption tower. The ammonia absorption tower is divided into the first ammonia absorption and separation section and the second ammonia absorption and separation section from bottom to top. The stripping gas of the double-tower stripping unit A2 first enters the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the lower section circulating phosphate ammonium solution after cooling also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section, and the ammonia in the stripping gas of the double-tower stripping unit A2 is strengthened to absorb and separate. The stripping gas of the double-tower stripping unit A2 after washing ammonia enters the first overflow chamber of the first ammonia absorption and separation section, and then is collected by the first overflow chamber and enters the gas inlet of the second feed chamber of the second ammonia absorption and separation section. The lower section circulating phosphate ammonium solution after washing ammonia is discharged from the liquid outlet of the first underflow chamber of the first ammonia absorption and separation section, part of which enters the lower section circulation pump, and the remaining part enters the rich liquid pump. The cooled phosphate ammonium lean liquid enters the liquid inlet of the second feed chamber of the second ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas of the double-tower stripping unit A2. The acid gas after ammonia washing enters the second overflow chamber of the second ammonia absorption and separation section, and is collected from the second overflow chamber and discharged from the top of the ammonia absorption tower. The phosphate ammonium lean liquid after ammonia washing is discharged from the liquid outlet of the second bottom flow chamber of the second ammonia absorption and separation section, and enters the liquid inlet of the first bottom flow chamber of the first ammonia absorption and separation section.

[0021] The acid gas and separation gas of the optimized side-line single steam stripper unit A3 directly enter the ammonia absorber from bottom to top, and are washed and separated by the ammonium phosphate solution of the three ammonia absorption and separation sections, and the ammonia therein is recovered, and condensed and cooled at the same time. The acid gas after ammonia washing is discharged from the top of the ammonia absorber. The ammonia absorber is divided into the first ammonia absorption and separation section, the second ammonia absorption and separation section, and the third ammonia absorption and separation section from bottom to top. The acid gas and separation gas of the side-line single steam stripping tower unit A3 first enter the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the cooled lower-stage circulating phosphate ammonium solution also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section, so as to enhance the absorption and separation of ammonia in the acid gas and separation gas of the side-line single steam stripping tower unit A3. The acid gas and separation gas of the side-line single steam stripping tower unit A3 after ammonia washing enter the first overflow chamber of the first ammonia absorption and separation section, and are then collected by the first overflow chamber and enter the gas inlet of the second feed chamber of the second ammonia absorption and separation section. The lower-stage circulating phosphate ammonium solution after ammonia washing is discharged from the liquid outlet of the first bottom flow chamber of the first ammonia absorption and separation section, part of which enters the lower-stage circulation pump, and the remaining part enters the rich liquid pump. The cooled middle-stage circulating ammonium phosphate solution also enters the second feed chamber liquid inlet of the second ammonia absorption and separation section, further strengthening the absorption and separation of ammonia in the acid gas and separation gas of the side-line single steam stripping tower unit A3. The acid gas and separation gas of the side-line single steam stripping tower unit A3 after ammonia washing enter the second overflow chamber of the second ammonia absorption and separation section, and are collected by the second overflow chamber to enter the third feed chamber gas inlet of the third ammonia absorption and separation section. The middle-stage circulating ammonium phosphate solution after ammonia washing is discharged from the second bottom flow chamber liquid outlet of the second ammonia absorption and separation section, part of which enters the middle-stage circulation pump, and the remaining part enters the first bottom flow chamber liquid inlet of the first ammonia absorption and separation section. The cooled phosphate ammonium lean liquid enters the liquid inlet of the third feed chamber of the third ammonia absorption and separation section, and finally strengthens the absorption and separation of ammonia in the acid gas and the separation gas of the side line single steam stripping tower unit A3. The acid gas after ammonia washing enters the overflow chamber 3 of the third ammonia absorption and separation section, and is collected from the overflow chamber 3 and discharged from the top of the ammonia absorption tower. The phosphate ammonium lean liquid after ammonia washing is discharged from the liquid outlet of the third underflow chamber of the third ammonia absorption and separation section, and enters the liquid inlet of the second underflow chamber of the second ammonia absorption and separation section.

[0022] Furthermore, the acid gas pressure at the outlet of the ammonia absorption tower top is not less than 0.1 MPa (G), which is based on the inlet pressure required for the acid gas to pass through the pipeline to the combustion furnace of the sulfur recovery section originally designed outside the boundary area.

[0023] Furthermore, the ammonia absorption tower may also adopt a method of combining multiple ammonia absorption and separation sections up and down; or adopt a method of combining conventional fillers or tower trays with ammonia absorption and separation sections, wherein the conventional fillers or tower trays are placed before the absorption and separation sections, that is, the conventional fillers or tower trays first absorb and separate ammonia in the stripping gas or acid gas and the separation gas, and the ammonia absorption and separation section further strengthens the absorption and separation of the remaining ammonia in the stripping gas or acid gas and the separation gas.

[0024] The optimized and adjusted single-tower stripping unit A1 stripping gas directly enters the ammonia absorption tower from bottom to top, and is washed and separated by a phosphate ammonium solution in a conventional packing section or a tray section and an ammonia absorption and separation section to recover ammonia. The acid gas after ammonia washing is discharged from the top of the ammonia absorption tower. The ammonia absorption tower is divided into a conventional packing section or a tray section and an ammonia absorption and separation section from bottom to top. The stripping gas of the single-tower stripping unit A1 first enters the lower part of the conventional packing section or the tray section, and the cooled lower section circulating phosphate ammonium solution enters the upper part of the conventional packing section or the tray section for spraying to absorb and separate the ammonia in the stripping gas of the single-tower stripping unit A1. The stripping gas of the single-tower stripping unit A1 after ammonia washing is collected and led out through the lead-out pipeline to the gas inlet of the feed chamber of the ammonia absorption and separation section. The lower section circulating phosphate ammonium solution after ammonia washing is discharged from the bottom of the tower, part of which enters the lower section circulation pump, and the remaining part enters the rich liquid pump. The cooled ammonium phosphate lean liquid enters the liquid inlet of the feed chamber of the ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas of the single-tower stripping unit A1. The acid gas after ammonia washing enters the overflow chamber of the ammonia absorption and separation section, and is collected from the overflow chamber and discharged from the top of the ammonia absorption tower. The ammonium phosphate lean liquid after ammonia washing is discharged from the underflow chamber of the ammonia absorption and separation section and enters the gas-liquid distributor on the top of the conventional packing section or the tower tray section.

[0025] Furthermore, the stripping gas from the single-tower stripping unit A1 or the stripping gas from the double-tower stripping unit A2 or the acid gas and separation gas from the side-line single stripping tower unit A3 directly enters the ammonia absorber from bottom to top, and is condensed and cooled while being separated by the phosphate ammonium solution. The concentration of high-quality ammonia water determines the amount of water condensed from the stripping gas or acid gas and separation gas in the ammonia absorber, which means that at a certain ammonia absorber outlet temperature, pressure and ammonia content in the acid gas, the amount of water condensed from the stripping gas or acid gas and separation gas in the ammonia absorber is obtained by the system water balance through parameters such as the mass concentration of the product ammonia water. This water balance system also includes the optimization and adjustment of the original designed stripping system.

[0026] Furthermore, the phosphate ammonium rich liquid is heat exchanged with the phosphate ammonium lean liquid in the lean-rich liquid heat exchanger, and then enters the deacidification tower to strengthen the removal of acidic components in the phosphate ammonium rich liquid, so that the deacidified phosphate ammonium rich liquid enters the desorption tower for desorption, so that the high-quality ammonia water is treated with S 2- The characterized acid component content is less than 3ppm. In order to ensure the deacidification effect of the deacidification tower, an indirect steam heater and a direct steam inlet are provided at the bottom of the deacidification tower.

[0027] Another object of the present invention is to disclose a system for recovering ammonia from a condensate stripping unit of a low temperature conversion process. The system has a reasonable structure, is effective and reliable, and can separate ammonia from stripping gas, or can separate ammonia from acid gas and separation gas, so that the ammonia content in the acid gas at the outlet of the ammonia absorption tower top is 0-10ppm, the pressure of the acid gas at the outlet of the ammonia absorption tower top is not less than 0.1MPa(G), and the high-quality ammonia water is S 2-The acidic component content is less than 3 ppm.

[0028] To achieve the above object, the technical solution adopted by the present invention is: a system for recovering ammonia from a condensate stripping unit of a low temperature conversion process comprises: an ammonia absorption tower and a deacidification tower, and the stripping unit is a single-tower stripping unit, a double-tower stripping unit or a side-line single stripping tower unit;

[0029] When the ammonia absorption tower is divided into the first ammonia absorption and separation section and the second ammonia absorption and separation section from bottom to top, the first feed chamber gas inlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower is respectively connected to the gas outlet at the top of the deacidification tower, connected to the original designed stripping tower top outlet of the single-tower stripping unit A1, or connected to the original designed H2S / CO2 stripping tower top outlet of the double-tower stripping unit A2, or connected to the original designed side-line single stripping tower top outlet of the side-line single stripping tower unit A3 and the separated gas outlet of the secondary separator, or connected to the original designed side-line single stripping tower top outlet of the side-line single stripping tower unit A3 and the separated gas outlet of the primary separator; the first feed chamber liquid inlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower is connected to the circulating phosphate ammonium solution outlet of the lower circulating liquid cooler; the first overflow chamber gas (collection) outlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower The outlet is connected to the gas inlet of the second feed chamber on the side wall of the second ammonia absorption and separation section at the top of the ammonia absorption tower; the liquid outlet of the first underflow chamber of the first ammonia absorption and separation section at the bottom of the ammonia absorption tower is respectively connected to the inlet of the lower section circulation pump and the inlet of the rich liquid pump; the second overflow chamber collecting outlet (the top outlet of the ammonia absorption tower) of the second ammonia absorption and separation section at the top of the ammonia absorption tower is connected to the inlet of the originally designed sulfur recovery section outside the boundary area or the originally designed flare inlet; the liquid inlet of the second feed chamber on the side wall of the second ammonia absorption and separation section at the top of the ammonia absorption tower is connected to the lean liquid outlet of the lean liquid cooler; the liquid outlet of the second underflow chamber on the side wall of the second ammonia absorption and separation section at the top of the ammonia absorption tower is connected to the liquid inlet of the first underflow chamber on the side wall of the first ammonia absorption and separation section at the bottom of the ammonia absorption tower; the phosphoric acid inlet and the venting liquid inlet of the first underflow chamber on the side wall of the first ammonia absorption and separation section at the bottom of the ammonia absorption tower are respectively connected to the phosphoric acid pump and the venting liquid pump outlet.

[0030] When the ammonia absorption tower is divided into the first ammonia absorption and separation section, the second ammonia absorption and separation section and the third ammonia absorption and separation section from bottom to top, the first feed chamber gas inlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower is respectively connected to the gas outlet at the top of the deacidification tower, connected to the original designed stripping tower top outlet of the single-tower stripping unit A1, or connected to the original designed H2S / CO2 stripping tower top outlet of the double-tower stripping unit A2, or connected to the original designed side-line single stripping tower top outlet of the side-line single stripping tower system A3 and the separated gas outlet of the secondary separator, or connected to the original designed side-line single stripping tower top outlet of the side-line single stripping tower system A3 and the separated gas outlet of the primary separator; the first feed chamber liquid inlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower is connected to the circulating phosphate ammonium solution outlet of the lower circulating liquid cooler; the first overflow chamber gas (collection) outlet of the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower is connected to the second feed chamber gas inlet of the side wall of the second ammonia absorption and separation section in the middle part of the ammonia absorption tower; the first underflow chamber liquid outlet ... The outlets are respectively connected to the inlet of the lower circulation pump and the inlet of the rich liquid pump; the gas (collection) outlet of the second overflow chamber on the side wall of the second ammonia absorption and separation section in the middle of the ammonia absorber is connected to the gas inlet of the third feed chamber on the side wall of the third ammonia absorption and separation section in the upper part of the ammonia absorber; the liquid inlet of the second feed chamber on the side wall of the second ammonia absorption and separation section in the middle of the ammonia absorber is connected to the outlet of the circulating phosphate ammonium solution of the middle-section circulating liquid cooler; the liquid outlet of the second underflow chamber of the second ammonia absorption and separation section in the middle of the ammonia absorber is respectively connected to the inlet of the middle-section circulation pump and the first underflow chamber liquid inlet of the first ammonia absorption and separation section in the lower part of the ammonia absorber; the collecting outlet of the overflow chamber 3 of the third ammonia absorption and separation section in the upper part of the ammonia absorber (the outlet at the top of the ammonia absorber) is connected to the inlet of the originally designed sulfur recovery section outside the boundary or the inlet of the originally designed flare; the liquid inlet of the third feed chamber on the side wall of the third ammonia absorption and separation section in the upper part of the ammonia absorber is connected to the lean liquid outlet of the lean liquid cooler; the liquid outlet of the third underflow chamber on the side wall of the third ammonia absorption and separation section in the upper part of the ammonia absorber is connected to the liquid inlet of the second underflow chamber on the side wall of the second ammonia absorption and separation section in the middle of the ammonia absorber. The phosphoric acid inlet and the venting liquid inlet of the first underflow cavity on the side wall of the first ammonia absorption and separation section at the lower part of the ammonia absorption tower are connected to the phosphoric acid pump and the venting liquid pump outlet respectively.

[0031] The ammonia absorption tower may also be provided with 4 or more ammonia absorption and separation sections, and the logistics connection between the sections is as described above.

[0032] The gas outlet at the top of the deacidification tower is connected to the gas inlet of the first feed chamber on the side wall of the first ammonia absorption and separation section at the bottom of the ammonia absorption tower, or is connected to the gas inlet of the conventional packing section or tray section at the bottom of the ammonia absorption tower. The rich liquid outlet at the bottom of the deacidification tower is connected to the inlet of the desorption tower feed pump. The rich liquid inlet at the upper side wall of the deacidification tower is connected to the rich liquid outlet of the lean-rich liquid heat exchanger. An indirect steam heater and a direct steam inlet are provided at the lower side wall of the deacidification tower. The heat source of the indirect steam heater can be the heating steam condensate from the desorption tower heater; when the heat is insufficient or the deacidification effect is not good, steam is used as the indirect heating heat source; when the deacidification effect is not good, direct steam can also be introduced.

[0033] Furthermore, the ammonia absorption tower is a vertical cylindrical structure, and two or more ammonia absorption and separation sections are arranged in the tower. The multiple ammonia absorption and separation sections are arranged from top to bottom, and each section is provided with a number of micro-cyclone separation tubes; a gas outlet is provided at the top of each ammonia absorption and separation section, a phosphate ammonium solution bottom outlet and a phosphate ammonium solution bottom inlet are provided at the bottom, and a gas side wall inlet and a phosphate ammonium solution side wall inlet are provided in the middle and upper part of the side wall; the gas outlet, the phosphate ammonium solution bottom outlet and the phosphate ammonium solution bottom inlet, the gas side wall inlet and the phosphate ammonium solution side wall inlet divide each absorption and separation section from top to bottom into three closed cavities, namely, an overflow chamber located in the top outlet area, a feed chamber in the feed area, and an underflow chamber in the bottom area, wherein the gas inlet and the liquid inlet of the feed chamber are sealed and isolated from each other, and the gas and the liquid are also completely isolated; each ammonia absorption and separation section is connected by a pipeline, the gas outlet of the overflow chamber of the lower ammonia absorption and separation section is connected to the gas inlet of the feed chamber of the upper ammonia absorption and separation section, and the liquid outlet of the underflow chamber of the upper ammonia absorption and separation section is connected to the liquid inlet of the underflow chamber of the lower ammonia absorption and separation section.

[0034] Furthermore, the micro-cyclone separation tube has a vertical cylindrical upper portion and a vertical conical lower portion; a gas outlet (or overflow outlet) is provided at the top, and a gas conduit tangential inlet and a liquid inlet are provided at the upper portion of the cylinder side, wherein the gas inlet is located above the liquid inlet, and the liquid inlet is composed of a plurality of injection holes distributed radially along the cylinder and distributed at a certain height along the axial direction; in each circle of radially distributed injection holes, the center line of each injection hole is eccentric to the center of the radial circle by more than 0° and less than or equal to 10°, that is, less than 90° to the tangential direction of the rotating airflow, and the eccentric angles of the radially distributed injection holes in each circle are also different; the ammonium phosphate solution enters the micro-cyclone separation tube through these injection holes, contacts the gas more fully, and achieves the effect of process enhancement and optimal separation of efficient separation; a solution outlet (or underflow outlet) is provided at the bottom of the cone; the top gas outlet pipe (or central overflow pipe) has its bottom pipe opening located below the liquid injection holes in the lowest circle.

[0035] When multiple micro-cyclone separation tubes are arranged in parallel, the gas inlet and the liquid inlet are sealed and separated from each other, and the gas and the liquid are also completely isolated; after the stripping gas or acid gas and the separation gas enter from the gas inlet of the feed chamber of the ammonia absorption and separation section, they enter each micro-cyclone separation tube through the tangential inlet of each gas duct respectively; after the phosphate ammonium solution enters from the liquid inlet of the feed chamber of the ammonia absorption and separation section, it enters each micro-cyclone separation tube through the injection hole respectively.

[0036] The stripping gas or acid gas and separation gas enter the micro-cyclone separation tube from the tangential inlet of the gas conduit of the micro-cyclone separation tube feed chamber, and flow downward in a spiral along the inner wall of the cylinder and cone, i.e., the outer cyclone. When approaching the lower part of the inner wall of the cone, it forms a reverse upward spiral flow, i.e., the inner cyclone, and then enters the gas outlet pipe (center overflow pipe), and finally is discharged from the gas outlet at the top of the gas outlet pipe; under the action of strong centrifugal force (supergravity), the inner and outer cyclones of the gas form a fierce gas phase cyclone fluid field in the micro-cyclone separation tube; ammonium phosphate After the solution enters from the numerous injection holes on the side wall of the cylinder, it continuously contacts, collides, and cuts the radially injected ammonium phosphate solution with the stripping gas or acid gas and separation gas rotating at high speed in the micro-cyclone separation tube, and the ammonium phosphate solution forms countless absorption droplets; the absorption droplets continue to move in the tube, and are continuously and fully in contact with the stripping gas or acid gas and separation gas, increasing the contact area and reaction rate of the gas-liquid two phases; the droplets with high density are finally thrown to the inner wall of the micro-cyclone separation tube by the external cyclone, and fall to the bottom of the cone with the cyclone, and flow out from the bottom solution outlet into the bottom flow cavity. When the lower part of the ammonia absorption and separation section is a conventional packing section or a tray section, the bottom of the bottom flow cavity of the ammonia absorption and separation section is open (not closed), and a pipe cap with a liquid seal is provided at the bottom solution outlet of each micro-cyclone separation tube, and the solution overflows through the liquid seal pipe cap and directly falls into the gas-liquid distributor provided in the conventional packing section or tray section below.

[0037] Furthermore, the deacidification tower is a vertical cylindrical structure, with a gas outlet at the top of the deacidification tower, an inlet for phosphate ammonium rich liquid after heat exchange at the upper part of the side wall of the deacidification tower, an indirect heater and a direct steam inlet at the lower part of the side wall of the deacidification tower, and an outlet for phosphate ammonium rich liquid after deacidification at the bottom of the deacidification tower; 5 to 20 porous arched baffle trays are arranged between the phosphate ammonium rich liquid inlet and the indirect heater and the direct steam inlet; two upper and lower adjacent porous arched baffle trays are arranged in a left-right staggered symmetrical manner; the phosphate ammonium rich liquid enters the first porous arched baffle tray from the phosphate ammonium rich liquid inlet on the side wall of the deacidification tower The water flows through the tower plate, overflows on the weir at the edge of the arched baffle, and falls into another tower plate below it. Part of the phosphate ammonium rich liquid also falls directly into another tower plate below it through the multiple holes on the tower plate, until the phosphate ammonium rich liquid falls into the bottom of the deacidification tower from the lowest porous arched baffle tower plate; the bottom of the deacidification tower is heated by indirect steam or direct steam, and the upward high-temperature steam generated contacts with the descending phosphate ammonium rich liquid plate by plate to enhance mass transfer, and the acidic components in the phosphate ammonium rich liquid are removed and discharged from the top of the deacidification tower. The phosphate ammonium rich liquid after enhanced deacidification enters the desorption tower feed pump from the bottom of the deacidification tower.

[0038] Furthermore, the mass concentration of phosphoric acid in the ammonium phosphate solution is 15-31%, the molar ratio of ammonia to phosphoric acid in the ammonium phosphate lean solution is 1.0-1.4, and the molar ratio of ammonia to phosphoric acid in the ammonium phosphate rich solution is 1.4-1.75.

[0039] The present invention discloses a process and system for recovering ammonia from a condensate stripping unit of a low-temperature conversion process. The process is reliable and the product ammonia water has high quality. Compared with the original designed stripping process, it has the following advantages:

[0040] 1) The present invention adopts enhanced surface interface and enhanced separation, so as to obtain high-quality ammonia water, wherein S 2- The acidic component content is less than 3 ppm.

[0041] After the optimization and adjustment, the ammonium phosphate rich liquid enters the deacidification tower after heat exchange and efficiently strengthens deacidification, and S is obtained from the top of the desorption tower. 2- The high-quality ammonia water with characterized acidic components less than 3ppm can be used for desulfurization and denitrification; it not only solves a series of problems including environmental protection caused by the difficulty in using ammonia water produced by the stripping method, but also realizes the comprehensive utilization of ammonia resources; the present invention is a solution with excellent benefits and environmental protection.

[0042] 2) The present invention adopts enhanced surface interface and enhanced separation, so that the ammonia content in the acid gas at the outlet of the ammonia absorption tower top is 0-10 ppm, which is conducive to the stable operation of the subsequent originally designed sulfur recovery section.

[0043] 3) The acid gas pressure at the top outlet of the ammonia absorption tower of the present invention is not less than 0.1 MPa (G), which meets the inlet pressure requirement of the acid gas into the combustion furnace of the sulfur recovery section of the original design.

[0044] 4) The present invention makes maximum use of the stock assets of the original design by optimizing and adjusting the original design stripping unit; compared with not using the original design stripping unit, it saves investment and increases the ammonia output.

[0045] 5) The present invention reduces the consumption of the original stripping design by optimizing and adjusting the original stripping unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is the original design schematic diagram of the single tower gas stripping unit A1;

[0047] Figure 2 The flowchart of the process for recovering ammonia from the condensate stripping unit of the low temperature conversion process in Example 1 is as follows;

[0048] Figure 3 This is the original design schematic diagram of the double tower gas stripping unit A2;

[0049] Figure 4 The flowchart of the process for recovering ammonia from the condensate stripping unit of the low temperature conversion process in Example 2 is as follows;

[0050] Figure 5 This is the original design schematic diagram of the side line single stripper unit A3;

[0051] Figure 6 The flowchart of the process for recovering ammonia from the condensate stripping unit of the low temperature conversion process in Example 3 is as follows;

[0052] Figure 7 This is the original design schematic diagram of the single-tower stripping unit A1;

[0053] Figure 8 The flowchart of the process for recovering ammonia from the condensate stripping unit of the low temperature conversion process in Example 4 is as follows;

[0054] Fig. 9 The microcyclone separation tube of the ammonia recovery system from the low temperature process condensate stripping unit of Example 5;

[0055] Fig.10 for Fig. 9 Cross-sectional view of a mesocyclone separation tube.

[0056] The reference numerals are:

[0057] 1-stripping tower, 2-stripping tower condenser, 3-stripping tower separator, 4-condensate heat exchanger, 5-H2S / CO2 stripping tower, 6-ammonia stripping tower, 7-H2S / CO2 stripping tower feed heater, 8-H2S / CO2 stripping tower condenser, 9-H2S / CO2 stripping tower separator, 10-ammonia stripping tower condenser, 11-final condenser, 12-side line single stripping tower, 13-side line single stripping tower cold feed cooler, 14-primary condenser, 15-primary separator, 16-secondary condenser, 17-secondary separator, 18-third stage condenser, 19-third stage separator, 20-gas ammonia refining facility, 21-ammonia scrubber, 22-ammonia cooling device, 23-first ammonia water intermediate tank, 24-ammonia water pump, 31-ammonia absorption tower, 32-lower section circulation pump, 33-lower section circulation liquid cooler, 34-middle section circulation pump, 35-middle section circulation liquid cooler, 36-rich liquid pump, 37-lean liquid cooler, 38-lean and rich liquid heat exchanger, 39-deacidification tower, 40-desorption tower feed pump, 41-upper desorption tower cooler, 42-lower desorption tower cooler, 43-desorption tower, 44-second ammonia water intermediate tank, 45-desorption tower heater, 46-micro-cyclone separation tube, 461-gas conduit tangential inlet, 462-tube top gas outlet, 463-injection hole, 464-bottom solution outlet, 465-central overflow pipe. DETAILED DESCRIPTION

[0058] The present invention is further described below in conjunction with embodiments:

[0059] Example 1

[0060] This embodiment discloses a process and system for recovering ammonia from a low temperature conversion process condensate stripping unit, such as Figure 1-2 As shown, a single-tower stripping unit A1 (original design) is adopted, including a stripping tower 1, a stripping tower condenser 2, a stripping tower separator 3, a condensate heat exchanger 4, an ammonia water cooler 22, an ammonia absorber 31, a lower section circulating pump 32, a lower section circulating liquid cooler 33, a rich liquid pump 36, a lean liquid cooler 37, a lean and rich liquid heat exchanger 38, a deacidification tower 39, a desorption tower feed pump 40, an upper desorption tower cooler 41, a lower desorption tower cooler 42, a desorption tower 43, a second ammonia water intermediate tank 44, and a desorption tower heater 45.

[0061] Description of the original design stripping process: The low-temperature process condensate collected from each separator in the original design is heat exchanged with the stripping wastewater from the bottom of the stripping tower 1 in the condensate heat exchanger 4, and then enters the upper part of the stripping tower 1; the stripping wastewater after heat exchange is sent back to the slag water treatment section of the original design outside the boundary area; the high-pressure flash steam from the slag water treatment section of the original design outside the boundary area enters the lower part of the stripping tower 1 for heating, the flash steam from the boiler blowdown separator of the original design outside the boundary area also enters the lower part of the stripping tower 1 for heating, and the low-pressure steam from the original design outside the boundary area also enters the stripping tower 1 lower part is heated; the stripping gas at the top of the stripping tower 1 enters the stripping tower condenser 2, and after being cooled by cooling water, the gas-liquid two-phase enters the stripping tower separator 3; the acid gas at the top of the stripping tower separator 3 goes to the sulfur recovery section originally designed outside the boundary area, and the ammonia water at the bottom of the stripping tower separator 3 is sent back to the desulfurization tower of the originally designed thermal power device outside the boundary area or the water-coal slurry produced by the originally designed rod mill; the ammonia content in the acid gas is 10000-30000ppm, the hydrogen sulfide content in the ammonia water is 550-1200ppm, and the ammonia content in the stripping wastewater is ≤200ppm.

[0062] Description of the original designed steam stripping process after optimization and adjustment and the description of the new designed ammonium phosphate process:

[0063] Part of the low-temperature process condensate collected from various separators in the original design enters the condensate heat exchanger 4, and after heat exchange with the stripping wastewater from the bottom of the stripping tower 1, enters the upper part of the stripping tower 1, and the remaining part of the low-temperature process condensate is mixed with the low-temperature process condensate after heat exchange and enters the upper part of the stripping tower 1; the stripping wastewater after heat exchange is sent back to the slag water treatment section of the original design outside the boundary area; the high-pressure flash steam from the slag water treatment section of the original design outside the boundary area enters the lower part of the stripping tower 1 for heating, and the flash steam from the boiler blowdown separator of the original design outside the boundary area also enters the lower part of the stripping tower 1 for heating, adjusting the original design of the low-pressure steam heating; the stripping gas at the top of the stripping tower 1 directly enters the ammonia absorption tower 31 of the newly designed phosphate ammonium unit; the ammonia content in the stripping wastewater is ≤200ppm.

[0064] The stripping gas at the top of the stripping tower 1 enters the ammonia absorption tower 31 from bottom to top, and is washed and separated by the ammonium phosphate solution in the two ammonia absorption and separation sections in the ammonia absorption tower 31, and the ammonia therein is recovered, and is condensed and cooled at the same time, and the acid gas after ammonia washing is discharged from the top of the ammonia absorption tower 31. The ammonia absorption tower 31 is divided into a first ammonia absorption and separation section and a second ammonia absorption and separation section from bottom to top. The stripping gas first enters the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the cooled lower circulating phosphate ammonium solution also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section to strengthen the absorption and separation of ammonia in the stripping gas. The stripping gas after ammonia washing enters the first overflow chamber of the first ammonia absorption and separation section, and then enters the second feed chamber gas inlet of the second ammonia absorption and separation section after being collected by the first overflow chamber. The lower circulating phosphate ammonium solution after ammonia washing is discharged from the liquid outlet of the first bottom flow chamber of the first ammonia absorption and separation section, part of which enters the lower circulating pump 32, and the remaining part enters the rich liquid pump 36; the phosphate ammonium solution at the outlet of the lower circulating pump 32 is cooled by cooling water in the lower circulating liquid cooler 33, and then enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section. The cooled ammonium phosphate lean liquid enters the second feed chamber liquid inlet of the second ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas, and the acid gas after ammonia washing enters the second overflow chamber of the second ammonia absorption and separation section, and is discharged from the top outlet of the ammonia absorption tower 31 after being collected from the second overflow chamber, and sent back to the sulfur recovery section originally designed outside the boundary area; the mass concentration of phosphoric acid in the ammonium phosphate solution is 25-31%; the molar ratio of ammonia to phosphoric acid in the ammonium phosphate lean liquid is 1.25-1.35; the ammonium phosphate lean liquid after ammonia washing is discharged from the second underflow chamber liquid outlet 2 of the second ammonia absorption and separation section, and enters the first underflow chamber liquid inlet 1 of the first ammonia absorption and separation section. The ammonia content in the acid gas at the top outlet of the ammonia absorption tower 31 is ≤7ppm, and the acid gas pressure is 0.11MPa(G).The phosphate ammonium rich liquid at the outlet of the rich liquid pump 36 is heat exchanged with the phosphate ammonium lean liquid discharged from the bottom of the desorption tower 43 in the lean-rich liquid heat exchanger 38, and then enters the deacidifier 39 for enhanced deacidification. The gas at the top of the deacidifier 39 enters from the first feed chamber gas inlet of the first ammonia absorption and separation section of the ammonia absorption tower 31; the molar ratio of ammonia to phosphoric acid in the phosphate ammonium rich liquid is 1.65-1.75; the steam condensate from the desorption tower heater 45 continuously enters the indirect heater at the bottom of the deacidifier 39 to provide heat for enhanced deacidification, and the heated steam condensate is discharged outside the boundary area; the deacidified phosphate ammonium rich liquid is sent to the upper desorption tower cooler 41 by the desorption tower feed pump 40, and enters the upper part of the desorption tower 43 after heat exchange with the ammonia vapor coming out of the top of the desorption tower 43; the bottom of the desorption tower 43 The phosphate ammonium lean liquid discharged from the upper part exchanges heat with the phosphate ammonium rich liquid and is cooled by cooling water in the lean-rich liquid heat exchanger 38 and the lean liquid cooler 37 respectively, and then enters the liquid inlet of the second feed chamber of the second ammonia absorption and separation section of the ammonia absorption tower 31; the medium-pressure steam from outside the boundary area enters the desorption tower heater 45 to heat the phosphate ammonium lean liquid from the bottom of the desorption tower 43 to provide heat for desorption, and the steam condenses into the indirect heater at the bottom of the deacidification tower 39; the gas-liquid two-phase at the bottom of the upper desorption tower cooler 41 enters the lower desorption tower cooler 42, is further condensed and cooled by cooling water, and then flows into the second ammonia water intermediate tank 44, and the ammonia water is then cooled by cooling water in the ammonia water cooler 22, and then sent back to the desulfurization tower of the originally designed thermal power device outside the boundary area; the ammonia water is concentrated in S. 2- The characterized acidic components were <2.5 ppm.

[0065] The main contents of the optimization and adjustment of the original designed stripping process are shown in Table 1.

[0066] Table 1 The main contents of the optimization and adjustment of the original design stripping process are shown in the table below.

[0067]

[0068]

[0069] Example 2

[0070] This embodiment discloses a process and system for recovering ammonia from a low temperature conversion process condensate stripping unit, such as Figure 3-4As shown, a double-tower stripping unit A2 (original design) is adopted, including a condensate heat exchanger 4, an H2S / CO2 stripping tower 5, an ammonia stripping tower 6, an H2S / CO2 stripping tower feed heater 7, an H2S / CO2 stripping tower condenser 8, an H2S / CO2 stripping tower separator 9, an ammonia stripping tower condenser 10, a final condenser 11, an ammonia water cooler 22, an ammonia absorber 31, a lower section circulating pump 32, a lower section circulating liquid cooler 33, a rich liquid pump 36, a lean liquid cooler 37, a lean and rich liquid heat exchanger 38, a deacidification tower 39, a desorber feed pump 40, an upper desorber cooler 41, a lower desorber cooler 42, a desorber 43, a second ammonia water intermediate tank 44, and a desorber heater 45.

[0071] Description of the original design stripping process: The low-temperature process condensate collected from each separator of the original design is heat exchanged with the ammonia vapor from the top of the ammonia stripping tower 6 in the H2S / CO2 stripping tower feed heater 7, and then enters the upper part of the H2S / CO2 stripping tower 5; the bottom liquid of the bottom of the H2S / CO2 stripping tower 5 enters the upper part of the ammonia stripping tower 6; the gas phase of the upper part of the ammonia stripping tower 6 enters the lower part of the H2S / CO2 stripping tower 5; the ammonia vapor leaving the H2S / CO2 stripping tower feed heater 7 is condensed and cooled by cooling water in the ammonia stripping tower condenser 10, and the liquid phase returns to the upper part of the ammonia stripping tower 6 as reflux, and the gas phase is then condensed and cooled by cooling water in the final condenser 11, and the gas at the top of the final condenser 11 goes to the sulfur recovery section of the original design outside the boundary area, and the ammonia-containing condensate at the bottom of the final condenser 11 enters the H2S / CO2 stripping tower In the separator 9; the stripping wastewater discharged from the bottom of the ammonia stripping tower 6 is sent back to the originally designed gasification unit; the low-pressure steam from the originally designed enters the lower part of the ammonia stripping tower 6 for heating; the stripping gas at the top of the H2S / CO2 stripping tower 5 enters the H2S / CO2 stripping tower condenser 8, and after being condensed and cooled by cooling water, the gas-liquid two-phase enters the H2S / CO2 stripping tower separator 9; the acid gas at the top of the H2S / CO2 stripping tower separator 9 is mixed with the gas at the top of the final condenser 11 and then goes to the originally designed sulfur recovery section together, and the ammonia-containing condensate at the bottom of the H2S / CO2 stripping tower separator 9 is sent back to the originally designed refinery stripping device outside the boundary area for further treatment; the ammonia content in the acid gas is 8000-25000ppm, the hydrogen sulfide content in the ammonia-containing condensate is 800-2000ppm, and the ammonia content in the stripping wastewater is ≤200ppm.

[0072] Description of the original designed steam stripping process after optimization and adjustment and the description of the new designed ammonium phosphate process:

[0073] Part of the low-temperature process condensate collected from various separators in the original design enters the newly designed condensate heat exchanger 4, and after heat exchange with the stripping wastewater from the bottom of the ammonia stripping tower 6, enters the upper part of the H2S / CO2 stripping tower 5. The remaining part of the low-temperature process condensate is mixed with the low-temperature process condensate after heat exchange and enters the upper part of the H2S / CO2 stripping tower 5; the stripping wastewater after heat exchange is sent back to the original designed gasification unit outside the boundary area; the heat supply of the original designed low-pressure steam entering the lower part of the ammonia stripping tower 6 is adjusted; the stripping gas at the top of the H2S / CO2 stripping tower 5 directly enters the ammonia absorption tower 31 of the newly designed phosphate ammonium unit; the ammonia content in the stripping wastewater is ≤100ppm.

[0074] The stripping gas at the top of the H2S / CO2 stripping tower 5 enters the ammonia absorption tower 31 from bottom to top, and is washed and separated by the ammonium phosphate solution in the two ammonia absorption and separation sections in the ammonia absorption tower 31, and the ammonia therein is recovered, and is condensed and cooled at the same time, and the acid gas after ammonia washing is discharged from the top of the ammonia absorption tower 31. The ammonia absorption tower 31 is divided into a first ammonia absorption and separation section and a second ammonia absorption and separation section from bottom to top. The stripping gas first enters the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the cooled lower circulating phosphate ammonium solution also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section to strengthen the absorption and separation of ammonia in the stripping gas. The stripping gas after ammonia washing enters the first overflow chamber of the first ammonia absorption and separation section, and then enters the second feed chamber gas inlet of the second ammonia absorption and separation section after being collected by the first overflow chamber. The lower circulating phosphate ammonium solution after ammonia washing is discharged from the liquid outlet of the first bottom flow chamber of the first ammonia absorption and separation section, part of which enters the lower circulating pump 32, and the remaining part enters the rich liquid pump 36; the phosphate ammonium solution at the outlet of the lower circulating pump 32 is cooled by cooling water in the lower circulating liquid cooler 33, and then enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section. The cooled ammonium phosphate lean liquid enters the second feed chamber liquid inlet of the second ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas. The acid gas after ammonia washing enters the second overflow chamber of the second ammonia absorption and separation section, and is discharged from the top outlet of the ammonia absorption tower 31 after being collected from the second overflow chamber, and sent back to the sulfur recovery section originally designed outside the boundary area; the mass concentration of phosphoric acid in the ammonium phosphate solution is 24-30%; the molar ratio of ammonia to phosphoric acid in the ammonium phosphate lean liquid is 1.2-1.3; the ammonium phosphate lean liquid after ammonia washing is discharged from the second underflow chamber liquid outlet of the second ammonia absorption and separation section, and enters the first underflow chamber liquid inlet of the first ammonia absorption and separation section. The ammonia content in the acid gas at the top outlet of the ammonia absorption tower 31 is ≤5ppm, and the acid gas pressure is 0.105MPa(G).The phosphate ammonium rich liquid at the outlet of the rich liquid pump 36 is heat exchanged with the phosphate ammonium lean liquid discharged from the bottom of the desorption tower 43 in the lean-rich liquid heat exchanger 38, and then enters the deacidifier 39 for enhanced deacidification. The gas at the top of the deacidifier 39 enters from the first feed chamber gas inlet of the first ammonia absorption and separation section of the ammonia absorption tower 31; the molar ratio of ammonia to phosphoric acid in the phosphate ammonium rich liquid is 1.65-1.75; the medium-pressure steam from outside the boundary area enters the indirect heater at the bottom of the deacidifier 39, and the steam condensate is discharged outside the boundary area to enhance the deacidification heat supply; the deacidified phosphate ammonium rich liquid is sent to the upper desorption tower cooler 41 by the desorption tower feed pump 40, and enters the upper part of the desorption tower 43 after heat exchange with the ammonia vapor coming out of the top of the desorption tower 43; the bottom of the desorption tower 43 The discharged phosphate ammonium lean liquid exchanges heat with the phosphate ammonium rich liquid and is cooled by cooling water in the lean-rich liquid heat exchanger 38 and the lean liquid cooler 37 respectively, and then enters the liquid inlet of the second feed chamber of the second ammonia absorption and separation section of the ammonia absorption tower 31; the medium-pressure steam from outside the boundary area enters the desorption tower heater 45 to heat the phosphate ammonium lean liquid from the bottom of the desorption tower 43 to provide heat for desorption, and the steam condenses and is discharged outside the boundary area; the gas-liquid two-phase at the lower part of the upper desorption tower cooler 41 enters the lower desorption tower cooler 42, is further condensed and cooled by cooling water, and then flows into the second ammonia water intermediate tank 44, and the ammonia water is then cooled by cooling water in the ammonia water cooler 22, and then sent back to the originally designed thermal power device outside the boundary area for desulfurization and denitrification; S in the ammonia water 2- The characterized acidic components were <2.0 ppm.

[0075] The main contents of the optimization and adjustment of the original double-tower stripping process are shown in Table 2.

[0076] Table 2 The main contents of the optimization and adjustment of the original double-tower stripping process are shown in the table below.

[0077]

[0078] Example 3

[0079] This embodiment discloses a process and system for recovering ammonia from a low temperature conversion process condensate stripping unit, such as Figure 5-6As shown, a side-line single steam stripping tower stripping unit A3 (original design) is adopted, including a steam stripping tower separator 3, a condensate heat exchanger 4, a side-line single steam stripping tower 12, a side-line single steam stripping tower cold feed cooler 13, a primary condenser 14, a primary separator 15, a secondary condenser 16, a secondary separator 17, a tertiary condenser 18, a tertiary separator 19, a gas ammonia refining facility 20, an ammonia scrubber 21, an ammonia water cooler 22, a first ammonia water intermediate tank 23, an ammonia water pump 24, an ammonia absorber 31, a lower section circulating pump 32, a lower section circulating liquid cooler 33, a middle section circulating pump 34, a middle section circulating liquid cooler 35, a rich liquid pump 36, a lean liquid cooler 37, a lean and rich liquid heat exchanger 38, a deacidification tower 39, a desorber feed pump 40, an upper desorber cooler 41, a lower desorber cooler 42, a desorber 43, a second ammonia water intermediate tank 44, and a desorber heater 45.

[0080] Original design stripping process description: The low-temperature process condensate collected from each separator of the original design is mixed with the separated liquid from the bottom outlet of the first-stage separator 15, the second-stage separator 17 and the third-stage separator 19, and then heat-exchanged with the side-line extracted gas of the side-line single stripping tower 12 in the first-stage condenser 14, and then heat-exchanged with the stripping wastewater from the bottom of the side-line single stripping tower 12 in the condensate heat exchanger 4, and then entered the upper part of the hot feed section of the side-line single stripping tower 12; the stripping wastewater after heat exchange is cooled by cooling water in the cold feed cooler 13 of the side-line single stripping tower, and then enters the side-line single stripping tower The upper part of the cooling feed section of the tower 12 is sent back to the originally designed gasification section outside the boundary area; the low-pressure steam from the original design enters the lower part of the side-line single steam stripping tower 12 for heating; the acid gas at the top of the side-line single steam stripping tower 12 enters the steam stripping tower separator 3, and the acid gas at the top of the steam stripping tower separator 3 goes to the originally designed sulfur recovery section outside the boundary area, and the acid water at the bottom of the steam stripping tower separator 3 is mixed with the low-temperature process condensate before the primary condenser 14; the side-line gas extracted from the side-line single steam stripping tower 12 first enters the primary condenser 14, and after heat exchange with the low-temperature process condensate, the separation liquid and the acid water mixture, enters the primary separator 15, and the primary The separated liquid at the bottom of the separator 15 is mixed with the low-temperature process condensate and the acid-water mixture before the primary condenser 14. The separated gas at the top of the primary separator 15 then enters the secondary condenser 16, is cooled by cooling water, and then enters the secondary separator 17. The separated liquid at the bottom of the secondary separator 17 is mixed with the low-temperature process condensate and the acid-water mixture before the primary condenser 14. The separated gas at the top of the secondary separator 17 enters the tertiary condenser 18, is cooled by cooling water, and then enters the tertiary separator 19. The separated liquid at the bottom of the tertiary separator 19 is mixed with the low-temperature process condensate and the acid-water mixture before the primary condenser 14. In the acid-water mixture, the separated gas at the top of the three-stage separator 19 enters the gas-ammonia refining facility 20, and after the acid components in the gas-ammonia are further removed by deep-cold separation and desulfurization agent, it enters the ammonia scrubber 21; the desalted water enters from the top of the ammonia scrubber 21, and the ammonia water enters the ammonia water cooler 22 from the bottom of the ammonia scrubber 21. After being cooled by cooling water, the ammonia water enters the first ammonia water intermediate tank 23; the ammonia water is pumped out from the first ammonia water intermediate tank 23 by the ammonia water pump 24, most of which is sent back to the upper part of the ammonia scrubber 21, part of which is sent back to the gas-ammonia refining facility 20, and the rest is sent to the originally designed desulfurization and denitrification ammonia water tank. The ammonia content in the acid gas is 9000-12000ppm, the hydrogen sulfide content in the ammonia water is 500-1000ppm, and the ammonia content in the stripping wastewater is ≤100ppm.

[0081] Description of the original designed steam stripping process after optimization and adjustment and the description of the new designed ammonium phosphate process:

[0082] Most of the low-temperature process condensate collected from various separators in the original design is mixed with the separated liquid from the bottom of the first-stage separator 15, and then heat-exchanged with the side-line extracted gas of the side-line single steam stripping tower 12 in the first-stage condenser 14. After the heat exchange, it is heat-exchanged with the steam stripping wastewater from the bottom of the side-line single steam stripping tower 12 in the condensate heat exchanger 4, and then enters the upper part of the hot feed section of the side-line single steam stripping tower 12; the steam stripping wastewater after heat exchange is sent back to the original designed gasification section outside the boundary area; the remaining part of the low-temperature process condensate (before the first-stage condenser 14) is cooled by cooling water in the cold feed cooler 13 of the side-line single steam stripping tower, and then enters the side-line single steam stripping tower 12 The upper part of the cold feed section; adjust the heat supply of the originally designed low-pressure steam entering the lower part of the side-line single steam stripping tower 12; the acid gas at the top of the side-line single steam stripping tower 12 directly enters the ammonia absorption tower 31 of the newly designed phosphate ammonium unit; the side-line extracted gas of the side-line single steam stripping tower 12 first enters the primary condenser 14, and after heat exchange with the mixed liquid of the low-temperature process condensate and the separation liquid, enters the primary separator 15, the separation liquid at the bottom of the primary separator 15 is mixed with the low-temperature process condensate before the primary condenser 14, and the separation gas at the top of the primary separator 15 directly enters the ammonia absorption tower 31 of the newly designed phosphate ammonium unit; the ammonia content in the stripping wastewater is ≤100ppm.

[0083] The acid gas at the top of the side-line single steam stripping tower 12 and the separated gas at the top of the primary separator 15 are mixed and enter the ammonia absorption tower 31 from bottom to top, and are washed and separated by the ammonium phosphate solution in the three ammonia absorption and separation sections in the ammonia absorption tower 31, and the ammonia therein is recovered, and condensed and cooled at the same time, and the acid gas after ammonia washing is discharged from the top of the ammonia absorption tower 31. The ammonia absorption tower 31 is divided into the first ammonia absorption and separation section, the second ammonia absorption and separation section, and the third ammonia absorption and separation section from bottom to top. The acid gas and the separated gas firstly enter the gas inlet of the first feed chamber of the first ammonia absorption and separation section, and the cooled lower circulating phosphate ammonium solution also enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section to strengthen the absorption and separation of ammonia in the stripping gas. The acid gas and the separated gas after ammonia washing enter the first overflow chamber of the first ammonia absorption and separation section, and then enter the gas inlet of the second feed chamber of the second ammonia absorption and separation section after being collected by the first overflow chamber. The lower circulating phosphate ammonium solution after ammonia washing is discharged from the liquid outlet of the first bottom flow chamber of the first ammonia absorption and separation section, part of which enters the lower circulating pump 32, and the remaining part enters the rich liquid pump 36; the phosphate ammonium solution at the outlet of the lower circulating pump 32 is cooled by cooling water in the lower circulating liquid cooler 33, and then enters the liquid inlet of the first feed chamber of the first ammonia absorption and separation section. The cooled middle-stage circulating ammonium phosphate solution also enters the second feed chamber liquid inlet of the second ammonia absorption and separation section to strengthen the absorption and separation of ammonia in the acid gas and the separation gas. The acid gas and the separation gas after ammonia washing enter the second overflow chamber of the second ammonia absorption and separation section, and then enter the third feed chamber gas inlet of the third ammonia absorption and separation section after being collected by the second overflow chamber. The middle-stage circulating ammonium phosphate solution after ammonia washing is discharged from the second bottom flow chamber liquid outlet of the second ammonia absorption and separation section, part of which enters the middle-stage circulating pump 34, and the remaining part enters the first bottom flow chamber liquid inlet of the first ammonia absorption and separation section; the ammonium phosphate solution at the outlet of the middle-stage circulating pump 34 is cooled by cooling water in the middle-stage circulating liquid cooler 35, and then enters the liquid inlet of the second feed chamber of the second ammonia absorption and separation section. The cooled ammonium phosphate lean liquid enters the third feed chamber liquid inlet of the third ammonia absorption and separation section, further strengthens the absorption of the acid gas and the remaining ammonia in the separation gas stripping, and the acid gas after ammonia washing enters the overflow chamber 3 of the third ammonia absorption and separation section, and is discharged from the top of the ammonia absorption tower 31 after being collected from the overflow chamber 3, and sent back to the sulfur recovery section originally designed outside the boundary area; the mass concentration of phosphoric acid in the ammonium phosphate solution is 25-31%; the molar ratio of ammonia to phosphoric acid in the ammonium phosphate lean liquid is 1.2-1.25; the ammonium phosphate lean liquid after ammonia washing is discharged from the third underflow chamber liquid outlet of the third ammonia absorption and separation section, and enters the second underflow chamber liquid inlet of the second ammonia absorption and separation section. The ammonia content in the acid gas at the top outlet of the ammonia absorption tower 31 is ≤3ppm, and the acid gas pressure is 0.1MPa(G).The phosphate ammonium rich liquid at the outlet of the rich liquid pump 36 is heat exchanged with the phosphate ammonium lean liquid discharged from the bottom of the desorption tower 43 in the lean-rich liquid heat exchanger 38, and then enters the deacidifier 39 for enhanced deacidification. The gas at the top of the deacidifier 39 enters from the first feed chamber gas inlet of the first ammonia absorption and separation section of the ammonia absorption tower 31; the molar ratio of ammonia to phosphoric acid in the phosphate ammonium rich liquid is 1.65-1.75; the steam condensate from the desorption tower heater 45 continuously enters the indirect heater at the bottom of the deacidifier 39, and the low-pressure steam from outside the boundary area also enters the bottom of the deacidifier 39. In order to enhance the deacidification heating, the steam condensate in the indirect heater is discharged outside the boundary area; the deacidified phosphate ammonium rich liquid is sent to the upper desorption tower cooler 41 by the desorption tower feed pump 40, and enters the desorption after heat exchange with the ammonia vapor coming out of the top of the desorption tower 43 The upper part of the tower 43; the phosphate ammonium lean liquid discharged from the bottom of the desorption tower 43 is heat-exchanged with the phosphate ammonium rich liquid and cooled by cooling water in the lean-rich liquid heat exchanger 38 and the lean liquid cooler 37, respectively, and then enters the third feed chamber liquid inlet of the third ammonia absorption and separation section of the ammonia absorption tower 31; the medium-pressure steam from outside the boundary area enters the desorption tower heater 45 to heat the phosphate ammonium lean liquid from the bottom of the desorption tower 43 to provide heat for desorption, and the steam condensate enters the indirect heater at the bottom of the deacidification tower 39; the gas-liquid two-phase at the bottom of the upper desorption tower cooler 41 enters the lower desorption tower cooler 42, is further condensed and cooled by cooling water, and then flows into the second ammonia water intermediate tank 44, and the ammonia water is then in the ammonia water cooler 22, and then cooled by cooling water, and then the ammonia water is sent back to the desulfurization tower of the originally designed thermal power device outside the boundary area; S in the ammonia water. 2- The characterized acidic components were <2.5 ppm.

[0084] The main contents of the optimization and adjustment of the original design of the side-line single-tower stripping process are shown in Table 3.

[0085] Table 3 The main contents of the optimization and adjustment of the original design side-line single-tower stripping process are shown in the table below.

[0086]

[0087]

[0088] Example 4

[0089] This embodiment discloses a process and system for recovering ammonia from a low temperature conversion process condensate stripping unit, such as Figure 7-8 As shown, a single-tower stripping unit A1 (original design) is adopted, including a stripping tower 1, a stripping tower condenser 2, a stripping tower separator 3, a condensate heat exchanger 4, an ammonia water cooler 22, an ammonia absorber 31, a lower section circulating pump 32, a lower section circulating liquid cooler 33, a rich liquid pump 36, a lean liquid cooler 37, a lean and rich liquid heat exchanger 38, a deacidification tower 39, a desorption tower feed pump 40, an upper desorption tower cooler 41, a lower desorption tower cooler 42, a desorption tower 43, a second ammonia water intermediate tank 44, and a desorption tower heater 45.

[0090] Original design stripping process description: The low-temperature process condensate collected from each separator in the original design first exchanges heat with the stripping gas from the top of the stripping tower 1 in the stripping tower condenser 2, then enters the condensate heat exchanger 4, exchanges heat with the stripping wastewater from the bottom of the stripping tower 1, and then enters the upper part of the stripping tower 1; the stripping wastewater after heat exchange is sent back to the gray water treatment section of the original design outside the boundary area; the flash steam from the gray water treatment section of the original design outside the boundary area enters the lower part of the stripping tower 1 for heating, and the low-pressure steam from the original design also enters The stripping gas at the top of the stripping tower 1 enters the stripping tower condenser 2, and after being cooled by the low-temperature process condensate, the gas-liquid two-phase enters the stripping tower separator 3; the acid gas at the top of the stripping tower separator 3 goes to the original designed flare outside the boundary area, and the ammonia water at the bottom of the stripping tower separator 3 is sent back to the original designed coal grinding water tank outside the boundary area; the ammonia content in the acid gas is 9000-25000ppm, the hydrogen sulfide content in the ammonia water is 750-3500ppm, and the ammonia content in the stripping wastewater is ≤150ppm.

[0091] Description of the original designed steam stripping process after optimization and adjustment and the description of the new designed ammonium phosphate process:

[0092] Part of the low-temperature process condensate collected from each separator in the original design enters the condensate heat exchanger 4, and after heat exchange with the stripping wastewater from the bottom of the stripping tower 1, enters the upper part of the stripping tower 1, and the remaining part of the low-temperature process condensate is mixed with the low-temperature process condensate after heat exchange, and enters the upper part of the stripping tower 1; the stripping wastewater after heat exchange is sent back to the gray water treatment section of the original design outside the boundary area; the flash steam from the gray water treatment section of the original design outside the boundary area enters the lower part of the stripping tower 1 for heating, and adjusts the heating amount of the low-pressure steam entering the lower part of the stripping tower 1 in the original design; the stripping gas at the top of the stripping tower 1 directly enters the ammonia absorption tower 31 of the newly designed phosphate ammonium unit; the ammonia content in the stripping wastewater is ≤100ppm.

[0093] The stripping gas at the top of the stripping tower 1 enters the ammonia absorption tower 31 from bottom to top, and is washed and separated by the phosphate ammonium solution in a packing section and an ammonia absorption and separation section in the ammonia absorption tower 31, and the ammonia therein is recovered. At the same time, it is condensed and cooled, and the acid gas after ammonia washing is discharged from the top of the ammonia absorption tower 31. The ammonia absorption tower 31 is divided into a packing section and an ammonia absorption and separation section from bottom to top. The stripping gas first enters the lower part of the packing section, and the cooled lower circulating phosphate ammonium solution enters the upper part of the packing section to absorb and separate the ammonia in the stripping gas. The stripping gas after ammonia washing enters the upper ammonia absorption and separation section. The lower circulating phosphate ammonium solution after ammonia washing is discharged from the liquid at the bottom of the ammonia absorption tower 31, and part of it enters the lower circulating pump 32, and the remaining part enters the rich liquid pump 36; the phosphate ammonium solution at the outlet of the lower circulating pump 32 is cooled by cooling water in the lower circulating liquid cooler 33, and then enters the upper part of the packing section. The cooled ammonium phosphate lean liquid enters the liquid inlet of the feed chamber of the ammonia absorption and separation section, further strengthening the absorption and separation of the remaining ammonia in the stripping gas. The acid gas after ammonia washing enters the overflow chamber of the ammonia absorption and separation section, and is discharged from the top of the ammonia absorption tower 31 after being collected from the overflow chamber, and sent back to the original designed flare outside the boundary area; the mass concentration of phosphoric acid in the ammonium phosphate solution is 25-30%; the molar ratio of ammonia to phosphoric acid in the ammonium phosphate lean liquid is 1.25-1.30; the ammonium phosphate lean liquid after ammonia washing is discharged from the bottom solution outlet (bottom flow outlet) of several micro-cyclone separation tubes with liquid-sealed pipe caps located in the bottom flow chamber of the ammonia absorption and separation section, and enters the gas-liquid distributor on the upper part of the packing section. The ammonia content in the acid gas at the top outlet of the ammonia absorption tower 31 is ≤10ppm, and the acid gas pressure is 0.10MPa(G). The phosphate ammonium rich liquid at the outlet of the rich liquid pump 36 is heat exchanged with the phosphate ammonium lean liquid discharged from the bottom of the desorption tower 43 in the lean-rich liquid heat exchanger 38, and then enters the deacidifier 39 for enhanced deacidification. The gas at the top of the deacidifier 39 enters from the gas inlet at the lower part of the lower packing section of the ammonia absorber 31; the molar ratio of ammonia to phosphoric acid in the phosphate ammonium rich liquid is 1.65-1.75; the steam condensate from the desorption tower heater 45 continuously enters the indirect heater at the bottom of the deacidifier 39 to provide heat for enhanced deacidification, and the heated steam condensate is discharged outside the boundary area; the deacidified phosphate ammonium rich liquid is sent to the upper desorption tower cooler 41 by the desorption tower feed pump 40, and enters the upper part of the desorption tower 43 after heat exchange with the ammonia vapor coming out of the top of the desorption tower 43; the bottom of the desorption tower 43 The discharged ammonium phosphate lean liquid is respectively heat-exchanged with the ammonium phosphate rich liquid in the lean-rich liquid heat exchanger 38 and the lean liquid cooler 37 and cooled by cooling water, and then enters the liquid inlet of the feed chamber of the ammonia absorption and separation section of the ammonia absorption tower 31; the medium-pressure steam from outside the boundary area enters the desorption tower heater 45 to heat the ammonium phosphate lean liquid from the bottom of the desorption tower 43 to provide heat for desorption, and the steam condensate enters the indirect heater at the bottom of the deacidification tower 39; the gas-liquid two-phase at the bottom of the upper desorption tower cooler 41 enters the lower desorption tower cooler 42, is further condensed and cooled by cooling water, and then flows into the second ammonia water intermediate tank 44, and the ammonia water is then cooled by cooling water in the ammonia water cooler 22, and then sent back to the originally designed thermal power device outside the boundary area for desulfurization and denitrification; the ammonia water is desulfurized and denitrated as S 2-The characterized acidic components are <3 ppm.

[0094] The main contents of the optimization and adjustment of the original designed stripping process are shown in Table 4.

[0095] Table 4 The main contents of the optimization and adjustment of the original design stripping process are shown in the table below.

[0096]

[0097] Example 5

[0098] This embodiment discloses a system for recovering ammonia from a low temperature process condensate stripping unit, such as Figure 9-10 As shown, a microcyclone separation tube 46 is used.

[0099] The stripping gas or acid gas and separation gas enter from the tangential inlet 461 of the gas conduit of the micro-cyclone separation tube 46, flow downward in a spiral along the inner wall of the cylinder and the cone, i.e., an outer cyclone, and when approaching the bottom of the inner wall of the cone, it forms a reverse upward spiral flow, i.e., an inner cyclone, and then enters the gas outlet pipe (central overflow pipe 465), and is finally discharged from the gas outlet 462 at the top of the gas outlet pipe; under the action of strong centrifugal force (supergravity), the inner and outer cyclones of the gas form a fierce gas phase cyclone fluid field in the micro-cyclone separation tube 46; ammonium phosphate After the solution enters from the numerous injection holes 463 on the side wall of the cylinder, it continuously contacts, collides and cuts the radially injected phosphate ammonium solution with the stripping gas or acid gas and separation gas rotating at a high speed in the micro-cyclone separation tube, and the phosphate ammonium solution forms countless absorption droplets; the absorption droplets continue to move in the tube, continuously and fully contacting with the stripping gas or acid gas and separation gas, thereby increasing the contact area and reaction rate of the gas-liquid two phases; the droplets with high density are finally thrown to the inner wall of the micro-cyclone separation tube 46 by the external cyclone, and fall to the bottom of the cone with the cyclone, and flow out from the bottom solution outlet 464.

[0100] like Fig. 9 and Fig.10 As shown in , in each circle of radially distributed injection holes, the center line of each injection hole is 5° off-center from the center of the radial circle, that is, the angle with the tangent direction of the rotating airflow is 85°, which is beneficial to further enhance the full contact between the gas and liquid phases.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for recovering ammonia from a low temperature conversion process condensate stripping unit, characterized in that: The following steps are involved: Optimize and adjust the stripping process so that the stripping gas from the stripping unit directly enters the ammonia absorber of the phosphate ammonium unit, or the acid gas and separation gas from the stripping process directly enter the ammonia absorber of the phosphate ammonium unit, and the acid gas after enhanced ammonia washing is sent to the existing sulfur recovery section or flare, and the phosphate ammonium rich liquid enters the desorption tower after heat exchange and enhanced deacidification, and the ammonia vapor at the top of the desorption tower is condensed and cooled to obtain high-quality ammonia water, wherein the high-quality ammonia water is S 2- The characterized acidic component content is less than 3ppm. In addition, the ammonia content in the acid gas at the top outlet of the ammonia absorption tower is 0~10ppm, and the acid gas pressure at the top outlet of the ammonia absorption tower is not less than 0.1MPa(G); The optimized steam stripping process is any one of the following: When the stripping unit is a single-tower stripping unit A1, the stripping process thereof is optimized and adjusted, including the following steps: deactivating the stripping tower condenser and the stripping tower separator; utilizing the stripping tower and the condensate heat exchanger, and possibly replacing part of the packing or trays in the tower; adjusting the stripping tower feed temperature and the stripping tower top temperature under the condition that the pressure at the top of the stripping tower remains unchanged or is slightly adjusted, so that the stripping gas at the top of the stripping tower directly enters the ammonia absorption tower; the ammonia content in the stripping tower bottom liquid remains unchanged; When the stripping unit is a double-tower stripping unit A2, the stripping process thereof is optimized and adjusted, including the following steps: stopping the H2S / CO2 stripping tower feed heater, the H2S / CO2 stripping tower condenser and the H2S / CO2 stripping tower separator, stopping the ammonia stripping tower condenser and the ammonia stripping tower reflux and final condenser; utilizing the H2S / CO2 stripping tower and the ammonia stripping tower, and possibly replacing part of the packing or trays in the H2S / CO2 stripping tower and / or the ammonia stripping tower, and adding a condensate heat exchanger; while the top pressure of the H2S / CO2 stripping tower remains unchanged or slightly adjusted, by adjusting the H2S / CO2 stripping tower feed temperature and the H2S / CO2 stripping tower top temperature, the stripping gas at the top of the H2S / CO2 stripping tower directly enters the ammonia absorption tower; the ammonia content in the bottom liquid of the ammonia stripping tower remains unchanged; When the stripping unit is a side-line single stripping tower unit A3, the stripping process thereof is optimized and adjusted, comprising the following steps: stopping the stripping tower separator, the three-stage condenser, the three-stage separator, the gas ammonia refining facility, the ammonia scrubber, the ammonia water cooler, the first ammonia water intermediate tank, and the ammonia water pump; utilizing the side-line single stripping tower, the side-line single stripping tower cold feed cooler, the first condenser, the first separator, the second condenser, the second separator, and the condensate heat exchanger; while the pressure and temperature of the side-line single stripping tower and the pressure of the second separator remain unchanged, by adjusting the outlet temperature of the second condenser, the acid gas at the top of the side-line single stripping tower and the separated gas at the outlet of the second separator are mixed and directly enter the ammonia absorption tower; the ammonia content in the bottom liquid of the side-line single stripping tower remains unchanged; the cold feed at the top of the side-line single stripping tower is changed from stripping wastewater to a low-temperature process condensate, and the low-temperature process condensate is cooled to a low temperature. The condensate comes from before the side-line separated liquid is mixed; or the stripping tower separator, secondary condenser, secondary separator, tertiary condenser, tertiary separator, gas-ammonia refining facility, ammonia scrubber, ammonia water cooler, first ammonia water intermediate tank, and ammonia water pump are shut down; the side-line single stripping tower, the side-line single stripping tower cold feed cooler, the primary condenser, the primary separator, and the condensate heat exchanger are utilized; when the operating pressure and temperature of the side-line single stripping tower and the pressure of the primary condenser remain unchanged, by adjusting the outlet temperature of the primary condenser, the acid gas at the top of the side-line single stripping tower and the separated gas at the outlet of the primary separator are mixed and directly enter the ammonia absorption tower; the ammonia content in the bottom liquid of the side-line single stripping tower remains unchanged; the top cold feed of the side-line single stripping tower is changed from stripping wastewater to low-temperature process condensate, and the low-temperature process condensate comes from before the side-line separated liquid is mixed.

2. The process for recovering ammonia from a low temperature conversion process condensate stripping unit according to claim 1, characterized in that: The low-temperature conversion process condensate comes from a conversion process device in the coal chemical industry and / or the refining industry, or also includes flash steam containing ammonia entering the stripping process.

3. The process for recovering ammonia from a low temperature conversion process condensate stripping unit according to claim 1, characterized in that: The stripping gas from the single-tower stripping unit A1, the stripping gas from the double-tower stripping unit A2, or the acid gas and separation gas from the side-line single stripping tower unit A3 directly enters the ammonia absorption tower of the phosphate ammonium unit from bottom to top, and is condensed and cooled while the ammonia therein is separated by the phosphate ammonium solution.

4. The process for recovering ammonia from a low temperature conversion process condensate stripping unit according to claim 1, characterized in that: The ammonia absorption tower adopts a method of combining multiple ammonia absorption and separation sections up and down; or adopts a method of combining conventional fillers or tower plates with ammonia absorption and separation sections, wherein the conventional fillers or tower plates are placed before the ammonia absorption and separation sections; the concentration of high-quality ammonia water determines the amount of water condensed from the stripping gas or acid gas and the separation gas in the ammonia absorption tower.

5. The process for recovering ammonia from a low temperature conversion process condensate stripping unit according to claim 1, characterized in that: The molar ratio of ammonia to phosphoric acid in the ammonium phosphate rich solution is 1.4~1.

75.

6. A system for recovering ammonia from a low temperature conversion process condensate stripping unit used in the process for recovering ammonia from a low temperature conversion process condensate stripping unit according to any one of claims 1 to 5, characterized in that: It includes an ammonia absorption tower and a deacidification tower; The connection relationship between the ammonia absorption tower, the deacidification tower and the stripping unit is as follows: The stripping unit is a single-tower stripping unit A1, a double-tower stripping unit A2 or a side-line single stripping tower unit A3; The gas inlet of the side wall of the ammonia absorption tower is respectively connected to the gas outlet of the top of the deacidification tower, connected to the top outlet of the stripping tower of the single-tower stripping unit A1, or connected to the top outlet of the H2S / CO2 stripping tower of the double-tower stripping unit A2, or connected to the top outlet of the side-line single stripping tower of the side-line single stripping tower unit A3 and the separated gas outlet of the secondary separator, or connected to the top outlet of the side-line single stripping tower of the side-line single stripping tower system A3 and the separated gas outlet of the primary separator; the top outlet of the ammonia absorption tower is connected to the inlet of the existing sulfur recovery section or to the inlet of the existing flare, and the ammonia The bottom outlet of the absorption tower is connected to the inlet of the lower circulation pump and the inlet of the rich liquid pump respectively, the phosphate ammonium solution inlet at the upper part of the side wall of the ammonia absorption tower is connected to the lean liquid outlet of the lean liquid cooler, the phosphate ammonium solution inlet at the lower part of the side wall of the ammonia absorption tower is connected to the phosphate ammonium solution outlet of the lower circulation liquid cooler, the phosphate ammonium solution outlet in the middle part of the side wall of the ammonia absorption tower is connected to the inlet of the middle circulation pump, the phosphate ammonium solution inlet in the middle part of the side wall of the ammonia absorption tower is connected to the phosphate ammonium solution outlet of the middle circulation liquid cooler, and the phosphoric acid inlet and the venting liquid inlet at the lower part of the side wall of the ammonia absorption tower are connected to the phosphoric acid pump and the venting liquid pump outlet respectively; The gas outlet at the top of the deacidification tower is connected to the gas inlet on the side wall of the ammonia absorption tower, the rich liquid outlet at the bottom of the deacidification tower is connected to the inlet of the desorption tower feed pump, the rich liquid inlet at the upper part of the side wall of the deacidification tower is connected to the rich liquid outlet of the lean-rich liquid heat exchanger, and an indirect steam inlet and a direct steam inlet are provided at the lower part of the side wall of the deacidification tower.

7. The system for recovering ammonia from a low temperature conversion process condensate stripping unit according to claim 6, characterized in that: The ammonia absorption tower is a vertical cylindrical structure, and two or more ammonia absorption and separation sections are arranged in the ammonia absorption tower, and the multiple ammonia absorption and separation sections are arranged from top to bottom, and each section is provided with a plurality of micro-cyclone separation tubes; each of the ammonia absorption and separation sections is provided with a gas outlet at the top, a phosphate ammonium solution bottom outlet and a phosphate ammonium solution bottom inlet at the bottom, and a gas side wall inlet and a phosphate ammonium solution side wall inlet are provided in the middle and upper part of the side wall; the gas outlet, the phosphate ammonium solution bottom outlet and the phosphate ammonium solution bottom inlet, the gas side wall inlet and the phosphate ammonium solution side wall inlet divide each absorption and separation section into three closed cavities from top to bottom, which are an overflow cavity located in the top outlet area, a feed cavity in the feed area, and an underflow cavity in the bottom area; Each ammonia absorption and separation section is connected by a pipeline, the overflow chamber gas outlet of the lower ammonia absorption and separation section is connected to the feed chamber gas inlet of the upper ammonia absorption and separation section, and the underflow chamber outlet of the upper ammonia absorption and separation section is connected to the underflow chamber inlet of the lower ammonia absorption and separation section.

8. The system for recovering ammonia from a low temperature process condensate stripping unit according to claim 7, characterized in that: The upper part of the micro-cyclone separation tube is a vertical cylindrical structure, and the lower part is a vertical conical structure; a gas outlet is arranged at the top, and a gas conduit tangential inlet and a liquid inlet are respectively arranged at the upper part of the side of the cylinder, wherein the gas inlet is located above the liquid inlet, and the liquid inlet is composed of a plurality of injection holes distributed along the radial direction of the cylinder and distributed at a certain height along the axial direction; in each circle of radially distributed injection holes, the center line of each injection hole is eccentric to the center of the radial circle by more than 0° and less than or equal to 10°, that is, the tangent direction of the rotating airflow is less than 90°, and the eccentric angle of the radially distributed injection holes in each circle is also different; the ammonium phosphate solution enters the micro-cyclone separation tube through these injection holes, contacts with the gas more fully, realizes the process of efficient separation intensification and the effect of optimal separation; a solution outlet is arranged at the bottom of the cone; the top gas outlet pipe, the bottom pipe mouth of which is located below the liquid injection holes of the lowest circle.

9. The system for recovering ammonia from a low temperature shift process condensate stripping unit according to claim 6, characterized in that: The deacidification tower is a vertical cylindrical structure, and is provided with 5 to 20 porous arched baffle trays below the rich liquid inlet and above the indirect steam inlet and the direct steam inlet.

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