Device for deamination, desulfurization and decyanation of coke oven gas by combined washing method and use method of device

Abstract

The invention relates to the field of production of coal gas, coke, tar or analogues by dry distillation of carbon-containing materials, in particular to a coke oven gas deamination, desulfurization and decyanation device adopting a combined washing method and a use method of the coke oven gas deamination, desulfurization and decyanation device. A coke oven gas deamination, desulfurization and decyanation device adopting a combined washing method comprises a desulfurization tower (1), the system is characterized by further comprising a desulfurization and deamination dual-purpose tower (2), a deamination tower (3), a filter (4), a decyanation tower (5), a deacidification tower (6), a compound deamination tower ammonia volatilization tower (7), a compound deamination tower fixed ammonium tower (8), a rich liquid pump (9), a first ammonia-rich water pump (10), a second ammonia-rich water pump (11), a first deamination water pump (12), a second deamination water pump (13), an ammonia distillation wastewater pump (14), a first cooler (15) and a second cooler (16), the desulfurization tower (1), the deamination tower (3), the decyanation tower (5), the deacidification tower (6) and the composite deamination tower volatile ammonia tower (7) are sequentially arranged, and the composite deamination tower fixed ammonium tower (8) is arranged at the upper part of the composite deamination tower volatile ammonia tower (7). The desulfurization, deamination and decyanation efficiency is high.

Description

Technical Field

[0001] The present invention relates to the field of dry distillation of carbon-containing materials to produce coal gas, coke, tar or the like, and specifically to an ammonia, sulfur and cyanide removal device by combined washing method for coke oven gas and its use method. Background Art

[0002] Coke oven gas contains various impurities, such as hydrogen sulfide, ammonia, hydrogen cyanide, carbon dioxide, benzene, naphthalene, tar, etc., which need to be removed before being used as fuel or product. At present, the existing combined washing method for ammonia, sulfur and cyanide removal can also partially absorb hydrogen cyanide in the gas while removing hydrogen sulfide and ammonia. Since the rich liquid contains substances such as cyanide ions, hydrogen sulfide, ammonia, etc., it causes serious corrosion to the equipment during desorption at high temperature. When the cyanide ions in the rich liquid exceed 400 mg / L, the equipment material needs to be selected above titanium material to meet the anti-corrosion requirements. In addition, the decomposition rate of ammonium sulfide and volatile ammonia during desorption of the rich liquid under normal pressure is low, and the efficiency of washing sulfur and ammonia in the gas by the gas ammonia removal tower and the desulfurization tower is low. After the desulfurization tower, the hydrogen sulfide is 300 Nm3~500 mg / Nm3, and after the ammonia removal tower, the ammonia is about 100 mg / Nm3, which cannot meet the quality requirements of the purified gas for subsequent users; due to the low desorption efficiency of the rich liquid under normal pressure, the high content of cyanide ions in the discharged wastewater affects biochemical treatment and cannot meet the existing environmental protection index requirements. Summary of the Invention

[0003] In order to overcome the defects of the prior art and provide an exhaust gas and waste liquid treatment device with high efficiency of desulfurization, ammonia removal and cyanide removal and good environmental protection, the present invention discloses an ammonia, sulfur and cyanide removal device by combined washing method for coke oven gas and its use method.

[0004] The present invention achieves the invention purpose through the following technical solutions: An ammonia, sulfur and cyanide removal device by combined washing method for coke oven gas, including a desulfurization tower, characterized in that: it further includes a dual-purpose desulfurization and ammonia removal tower, an ammonia removal tower, a filter, a cyanide removal tower, a deacidification tower, a volatile ammonia tower of the combined ammonia removal tower, a fixed ammonium tower of the combined ammonia removal tower, a rich liquid pump, a first rich ammonia water pump, a second rich ammonia water pump, a first ammonia removal water pump, a second ammonia removal water pump, an ammonia distillation wastewater pump, a first cooler and a second cooler, The desulfurization tower, the ammonia removal tower, the cyanide removal tower, the deacidification tower and the volatile ammonia tower of the combined ammonia removal tower are arranged in sequence, and the fixed ammonium tower of the combined ammonia removal tower is arranged on the upper part of the volatile ammonia tower of the combined ammonia removal tower; The lower part of the desulfurization tower is provided with a coke oven gas inlet, the gas outlet end at the top of the desulfurization tower is connected to the gas inlet end at the lower part of the ammonia removal tower through a gas transmission pipe, the top of the ammonia removal tower is provided with a coke oven gas discharge port, the liquid outlet end at the lower part of the ammonia removal tower is connected to the first rich ammonia water pump through a liquid transmission pipe, and then connected to the first liquid spraying port above the interior of the desulfurization tower through the first rich ammonia water pump; The liquid outlet end at the lower part of the desulfurization tower is connected to the liquid inlet end of the filter through a liquid delivery pipe in series with a rich liquid pump. The liquid outlet end of the filter is connected to the liquid inlet end at the lower part of the de-cyaniding tower through a liquid delivery pipe in series with a second rich ammonia water pump. A steam inlet is provided on the second rich ammonia water pump. The gas outlet end at the top of the de-cyaniding tower is connected to the gas inlet end at the upper part of the de-acidifying tower through a gas delivery pipe. A steam inlet is provided at the lower part of the de-cyaniding tower. A sour gas discharge port is provided at the top of the de-acidifying tower to produce sulfonic acid. The liquid outlet end at the lower part of the de-acidifying tower is connected to the liquid inlet end at the upper part of the volatile ammonia tower of the composite de-ammoniation tower through a liquid delivery pipe in series with a first de-ammoniation water pump. The liquid outlet end at the lower part of the de-acidifying tower is also connected to the second liquid spraying port above the interior of the desulfurization tower through a liquid delivery pipe in series with a first cooler. A steam inlet is provided at the lower part of the de-acidifying tower; The gas outlet end at the upper part of the volatile ammonia tower of the composite de-ammoniation tower is connected to the gas inlet end at the lower part of the fixed ammonium tower of the composite de-ammoniation tower through a gas delivery pipe. The liquid outlet end at the lower part of the volatile ammonia tower of the composite de-ammoniation tower is connected to the liquid inlet end at the upper part of the fixed ammonium tower of the composite de-ammoniation tower through a liquid delivery pipe in series with a second de-ammoniation water pump. The liquid outlet end at the lower part of the volatile ammonia tower of the composite de-ammoniation tower is also connected to the liquid spraying port above the interior of the de-ammoniation tower after being in series with a second cooler through a liquid delivery pipe in series with a second de-ammoniation water pump. A steam inlet is provided at the lower part of the volatile ammonia tower of the composite de-ammoniation tower. The liquid discharge port at the lower part of the fixed ammonium tower of the composite de-ammoniation tower is in series with an ammonia distillation wastewater pump.

[0005] The ammonia, desulfurization and de-cyaniding device by the combined washing method of coke oven gas is characterized in that: it further includes a desulfurization and de-ammoniation dual-purpose tower, The desulfurization and de-ammoniation dual-purpose tower is arranged between the desulfurization tower and the de-ammoniation tower; The gas outlet end at the top of the desulfurization tower is connected to the gas inlet end at the lower part of the desulfurization and de-ammoniation dual-purpose tower through a gas delivery pipe. The gas outlet end at the top of the desulfurization and de-ammoniation dual-purpose tower is connected to the gas inlet end at the lower part of the de-ammoniation tower through a gas delivery pipe. The liquid outlet ends at the lower parts of both the desulfurization and de-ammoniation dual-purpose tower and the de-ammoniation tower are respectively connected to a first rich ammonia water pump through liquid delivery pipes; The liquid outlet end at the lower part of the de-acidifying tower is respectively connected to the second liquid spraying port above the interior of the desulfurization tower and the second liquid spraying port above the interior of the desulfurization and de-ammoniation dual-purpose tower through a liquid delivery pipe in series with a first cooler. A steam inlet is provided at the lower part of the de-acidifying tower; The liquid outlet end at the lower part of the volatile ammonia tower of the composite de-ammoniation tower is respectively connected to the first liquid spraying port above the interior of the desulfurization and de-ammoniation dual-purpose tower and the liquid spraying port above the interior of the de-ammoniation tower after being in series with a second cooler through a liquid delivery pipe in series with a second de-ammoniation water pump.

[0006] The usage method of the ammonia, desulfurization and de-cyaniding device by the combined washing method of coke oven gas is characterized in that: it is implemented successively according to the following steps: Coke oven gas is input into the lower section of the desulfurization tower from the coke oven gas inlet at the lower part of the desulfurization tower. After cooling, the temperature drops to 20 °C to 21 °C. After desulfurization in the desulfurization tower, the coke oven gas is output from the gas outlet end at the top, and the rich liquid converges downward; The coke oven gas after desulfurization is input into the lower section of the ammonia removal tower from the air inlet end at the lower part of the ammonia removal tower. After ammonia removal in the ammonia removal tower, the coke oven gas is discharged from the coke oven gas discharge port at the top; The rich liquid in the lower section of the ammonia removal tower is suctioned by the first rich ammonia water pump and input into the first liquid spraying port above the interior of the desulfurization tower; The rich liquid in the lower section of the desulfurization tower is pumped by the rich liquid pump to the filter for filtration. Then it is mixed with steam in the second rich ammonia water pump and suctioned by the second rich ammonia water pump to be input into the lower section of the cyanide removal tower from the liquid inlet end at the lower part of the cyanide removal tower. After being mixed with steam in the cyanide removal tower, it is input into the desulfuric acid tower from the gas outlet end at the top through the gas transmission pipe and the air inlet end at the upper part of the desulfuric acid tower and mixed with steam. The acidic gas-containing gas escaping upward in the desulfuric acid tower is discharged from the top of the desulfuric acid tower for making sulfonic acid. The rich liquid collecting downward in the desulfuric acid tower is suctioned by the first ammonia removal water pump. Part of it is input into the volatile ammonia tower of the combined ammonia removal tower from the liquid inlet end at the upper part of the volatile ammonia tower of the combined ammonia removal tower, and the other part is cooled by the first cooler and then input into the second liquid spraying port above the interior of the desulfurization tower; After the rich liquid input into the volatile ammonia tower of the combined ammonia removal tower is mixed with steam, the alkaline gas-containing gas escaping upward is input into the fixed ammonium tower of the combined ammonia removal tower from the gas outlet end at the upper part through the gas transmission pipe and the air inlet end at the lower part of the fixed ammonium tower of the combined ammonia removal tower. The rich liquid collecting downward is suctioned by the second ammonia removal water pump. Part of it is input into the fixed ammonium tower of the combined ammonia removal tower from the liquid inlet end at the upper part of the fixed ammonium tower of the combined ammonia removal tower, and the other part is connected to the liquid spraying port above the interior of the ammonia removal tower through the liquid transmission pipe in series with the second cooler; The alkaline gas-containing gas escaping upward in the fixed ammonium tower of the combined ammonia removal tower is output to implement ammonia vapor decomposition, and the rich liquid collecting downward in the fixed ammonium tower of the combined ammonia removal tower is suctioned by the ammonia distillation wastewater pump to implement biochemical treatment.

[0007] The usage method of the coke oven gas combined washing method ammonia removal, desulfurization and cyanide removal device is characterized in that the following steps are sequentially implemented: The coke oven gas is input into the lower section of the desulfurization tower from the coke oven gas inlet at the lower part of the desulfurization tower. After cooling, the temperature drops to 20°C - 21°C. After desulfurization in the desulfurization tower, the coke oven gas is output from the gas outlet end at the top, and the rich liquid collects downward; The desulfurized coke oven gas is input into the lower section of the desulfurization and ammonia removal dual-purpose tower from the air inlet end at the lower part of the desulfurization and ammonia removal dual-purpose tower. After desulfurization and ammonia removal in the desulfurization and ammonia removal dual-purpose tower, the coke oven gas is output from the gas outlet end at the top, and the rich liquid collects downward; The coke oven gas after desulfurization and ammonia removal is input into the lower section of the ammonia removal tower from the air inlet end at the lower part of the ammonia removal tower. After ammonia removal in the ammonia removal tower, the coke oven gas is discharged from the coke oven gas discharge port at the top; The rich liquid in the lower sections of both the desulfurization and ammonia removal dual-purpose tower and the ammonia removal tower is suctioned by the first rich ammonia water pump and input into the first liquid spraying port above the interior of the desulfurization tower; The rich liquid in the lower section of the desulfurization tower is pumped by a rich liquid pump to a filter for filtration, then mixed with steam in the second rich ammonia water pump, and is suctioned by the second rich ammonia water pump and input into the lower section of the de-cyanation tower from the liquid inlet end at the lower part of the de-cyanation tower. After being mixed with steam in the de-cyanation tower, it is input into the de-acidification tower from the gas outlet end at the top through a gas transmission pipe and the gas inlet end at the upper part of the de-acidification tower and mixed with steam. The acidic gas-carrying gas escaping upward in the de-acidification tower is discharged from the top of the de-acidification tower for making sulfonic acid. The rich liquid collecting downward in the de-acidification tower is suctioned by the first de-ammonia water pump. Part of it is input into the volatile ammonia tower of the combined de-ammonia tower from the liquid inlet end at the upper part of the volatile ammonia tower of the combined de-ammonia tower, and the other part is cooled by the first cooler and then respectively input into the second liquid spraying port above the interior of the desulfurization tower and the second liquid spraying port above the interior of the desulfurization and de-ammonia dual-purpose tower; After the rich liquid input into the volatile ammonia tower of the combined de-ammonia tower is mixed with steam, the alkaline gas-carrying gas escaping upward is input into the fixed ammonium tower of the combined de-ammonia tower from the gas outlet end at the upper part through a gas transmission pipe and the gas inlet end at the lower part of the fixed ammonium tower of the combined de-ammonia tower. The rich liquid collecting downward is suctioned by the second de-ammonia water pump. Part of it is input into the fixed ammonium tower of the combined de-ammonia tower from the liquid inlet end at the upper part of the fixed ammonium tower of the combined de-ammonia tower, and the other part is respectively connected to the first liquid spraying port above the interior of the desulfurization and de-ammonia dual-purpose tower and the liquid spraying port above the interior of the de-ammonia tower through a liquid transmission pipe in series with the second cooler; The alkaline gas-carrying gas escaping upward in the fixed ammonium tower of the combined de-ammonia tower is output to implement ammonia gas decomposition, and the rich liquid collecting downward in the fixed ammonium tower of the combined de-ammonia tower is suctioned by an ammonia distillation waste water pump to implement biochemical treatment.

[0008] The usage method of the ammonia, sulfur, and cyanide removal device by the combined coke oven gas washing method is characterized in that: The residence time of the rich liquid in the de-cyanation tower is 10 min to 70 min, the operating temperature in the de-cyanation tower is 135 °C to 180 °C, and the operating pressure is 0.41 MPa to 0.8 MPa; The operating temperature in the de-acidification tower is 129 °C to 180 °C, and the operating pressure is 0.3 MPa to 0.8 MPa.

[0009] The rich liquid from the desulfurization tower is heated to 135°C - 180°C by a steam reboiler and enters the de-cyanation tower. The operating pressure is 0.41 MPa - 0.8 MPa, and the residence time in the de-cyanation tower is 10 min - 70 min. The cyanide ions in the rich liquid can be decomposed to less than 200 mg / L. The rich liquid after decomposing hydrogen cyanide enters the de-acidification tower for de-acidification. The de-acidification tower operates under pressurized conditions. The operating temperature of the de-acidification tower is 129°C - 180°C, and the operating pressure is 0.3 MPa - 0.8 MPa. After the rich liquid removes hydrogen sulfide, it becomes lean liquid. The lean liquid contains less than 0.7 g / L of hydrogen sulfide. One part is cooled to 22°C and sent to the desulfurization tower to wash hydrogen sulfide in the coal gas. The hydrogen sulfide in the coal gas after the desulfurization tower is less than 150 mg / Nm3. Another part is sent to the lower-stage volatile ammonia tower of the combined de-ammoniation to remove volatile ammonia. After removing volatile ammonia, it becomes de-ammoniated water with a volatile ammonia content of less than 300 mg / L. One part is cooled to 22°C and sent to the de-ammoniation tower to wash ammonia in the coal gas. The ammonia content in the coal gas after the de-ammoniation tower is less than 50 mg / Nm3. Another part of the de-ammoniated water is sent to the fixed ammonium tower of the combined de-ammoniation tower to remove fixed ammonium and becomes wastewater for biochemical treatment. The wastewater contains less than 50 mg / L of cyanide ions.

[0010] Currently, the existing combined washing method for ammonia and sulfur removal process cannot meet the requirements of subsequent users for desulfurization and de-ammoniation of coal gas, and does not effectively remove hydrogen cyanide in the desulfurized rich liquid, resulting in serious corrosion in atmospheric pressure de-acidification and ammonia distillation, and high cyanide ion content in the discharged wastewater, which affects biochemical treatment. The present invention solves the disadvantages of the existing process and provides a method with higher efficiency for ammonia removal, sulfur removal, and cyanide removal from coke oven gas. Specifically, the present invention has the following beneficial effects: 1. The decomposition rate of pressurized de-acidification is relatively higher than that of atmospheric pressure de-acidification. The lean liquid and de-ammoniated water contain relatively low amounts of hydrogen sulfide and volatile ammonia, which can reduce the liquid phase partial pressure of the lean liquid and de-ammoniated water. The sulfur and ammonia removal efficiency is lower than that of the existing technology. The sulfur and ammonia removal efficiency of the coal gas is high. The hydrogen sulfide content in the coal gas after the tower is less than 150 mg / Nm3, and the ammonia content is less than 50 mg / Nm3, which can meet the requirements of the next process.

[0011] 2. After the rich liquid removes hydrogen cyanide through the de-cyanation tower, the cyanide ion content in the rich liquid is reduced. The de-acidification tower and the combined ammonium tower can be made of S31603 material instead of the necessary TA2 material, which can meet the anti-corrosion requirements.

[0012] 3. After the rich liquid removes hydrogen cyanide through the de-cyanation tower, the cyanide ion content in the rich liquid is reduced. The cyanide ions in the discharged wastewater meet the requirements of biochemical treatment, ensuring the continuous and stable operation of biochemical treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention is further illustrated by the following specific examples. Example

[0015] An ammonia, sulfur and cyanide removal device by combined coke oven gas washing method, including a desulfurization tower 1, a dual-purpose desulfurization and ammonia removal tower 2, an ammonia removal tower 3, a filter 4, a cyanide removal tower 5, an acid removal tower 6, a volatile ammonia tower 7 of a combined ammonia removal tower, a fixed ammonium tower 8 of a combined ammonia removal tower, a rich liquid pump 9, a first rich ammonia water pump 10, a second rich ammonia water pump 11, a first ammonia removal water pump 12, a second ammonia removal water pump 13, an ammonia distillation waste water pump 14, a first cooler 15 and a second cooler 16, as Figure 1 shown, the specific structure is: The desulfurization tower 1, the dual-purpose desulfurization and ammonia removal tower 2, the ammonia removal tower 3, the cyanide removal tower 5, the acid removal tower 6 and the volatile ammonia tower 7 of the combined ammonia removal tower are arranged in sequence, and the fixed ammonium tower 8 of the combined ammonia removal tower is arranged on the upper part of the volatile ammonia tower 7 of the combined ammonia removal tower; The lower part of the desulfurization tower 1 is provided with a coke oven gas inlet, the gas outlet end at the top of the desulfurization tower 1 is connected to the gas inlet end at the lower part of the dual-purpose desulfurization and ammonia removal tower 2 through a gas transmission pipe, the gas outlet end at the top of the dual-purpose desulfurization and ammonia removal tower 2 is connected to the gas inlet end at the lower part of the ammonia removal tower 3 through a gas transmission pipe, the top of the ammonia removal tower 3 is provided with a coke oven gas discharge port, the liquid outlet ends at the lower parts of the dual-purpose desulfurization and ammonia removal tower 2 and the ammonia removal tower 3 are respectively connected to the first rich ammonia water pump 10 through a liquid transmission pipe, and then connected to the first liquid spraying port above the interior of the desulfurization tower 1 through the first rich ammonia water pump 10; The liquid outlet end at the lower part of the desulfurization tower 1 is connected to the liquid inlet end of the filter 4 through a liquid transmission pipe in series with the rich liquid pump 9, the liquid outlet end of the filter 4 is connected to the liquid inlet end at the lower part of the cyanide removal tower 5 through a liquid transmission pipe in series with the second rich ammonia water pump 11, the second rich ammonia water pump 11 is provided with a steam inlet, the gas outlet end at the top of the cyanide removal tower 5 is connected to the gas inlet end at the upper part of the acid removal tower 6 through a gas transmission pipe, the lower part of the cyanide removal tower 5 is provided with a steam inlet, the top of the acid removal tower 6 is provided with an acid discharge port for making sulfonic acid, the liquid outlet end at the lower part of the acid removal tower 6 is connected to the liquid inlet end at the upper part of the volatile ammonia tower 7 of the combined ammonia removal tower through a liquid transmission pipe in series with the first ammonia removal water pump 12, the liquid outlet end at the lower part of the acid removal tower 6 is also connected to the second liquid spraying port above the interior of the desulfurization tower 1 and the second liquid spraying port above the interior of the dual-purpose desulfurization and ammonia removal tower 2 respectively through a liquid transmission pipe in series with the first cooler 15, and the lower part of the acid removal tower 6 is provided with a steam inlet; The gas outlet end at the upper part of the volatile ammonia tower 7 of the combined ammonia removal tower is connected to the gas inlet end at the lower part of the fixed ammonium tower 8 of the combined ammonia removal tower through a gas transmission pipe, the liquid outlet end at the lower part of the volatile ammonia tower 7 of the combined ammonia removal tower is connected to the liquid inlet end at the upper part of the fixed ammonium tower 8 of the combined ammonia removal tower through a liquid transmission pipe in series with the second ammonia removal water pump 13, the liquid outlet end at the lower part of the volatile ammonia tower 7 of the combined ammonia removal tower is also connected to the first liquid spraying port above the interior of the dual-purpose desulfurization and ammonia removal tower 2 and the liquid spraying port above the interior of the ammonia removal tower 3 respectively through a liquid transmission pipe in series with the second ammonia removal water pump 13 and then in series with the second cooler 16, the lower part of the volatile ammonia tower 7 of the combined ammonia removal tower is provided with a steam inlet, and the liquid discharge port at the lower part of the fixed ammonium tower 8 of the combined ammonia removal tower is in series with the ammonia distillation waste water pump 14.

[0016] When this embodiment is in use, it is implemented in the following steps in sequence: The coke oven gas is input into the lower section of the desulfurization tower 1 from the coke oven gas inlet at the lower part of the desulfurization tower 1. After cooling, the temperature drops to 20°C to 21°C. After desulfurization in the desulfurization tower 1, the coke oven gas is output from the gas outlet end at the top, and the rich liquid converges downward to the lower section; The desulfurized coke oven gas is input into the lower section of the desulfurization and deammoniation dual-purpose tower 2 from the gas inlet end at the lower part of the desulfurization and deammoniation dual-purpose tower 2. After desulfurization and deammoniation in the desulfurization and deammoniation dual-purpose tower 2, the coke oven gas is output from the gas outlet end at the top, and the rich liquid converges downward to the lower section; The coke oven gas after desulfurization and deammoniation is input into the lower section of the deammoniation tower 3 from the gas inlet end at the lower part of the deammoniation tower 3. After deammoniation in the deammoniation tower 3, the coke oven gas is discharged from the coke oven gas discharge port at the top; The rich liquid in the lower sections of both the desulfurization and deammoniation dual-purpose tower 2 and the deammoniation tower 3 is suctioned by the first rich ammonia water pump 10 and input into the first liquid spraying port above the interior of the desulfurization tower 1; The rich liquid in the lower section of the desulfurization tower 1 is pumped by the rich liquid pump 9 to the filter 4 to remove oil impurities. Then, it is mixed with steam in the second rich ammonia water pump 11 and suctioned by the second rich ammonia water pump 11 to be input into the lower section of the decyanation tower 5 from the liquid inlet end at the lower part of the decyanation tower 5. After being mixed with steam in the decyanation tower 5, it passes through the gas outlet end at the top and is input into the decarboxylation tower 6 through the gas transmission pipe from the gas inlet end at the upper part of the decarboxylation tower 6 and mixed with steam. The acidic gas carried upward in the decarboxylation tower 6 is discharged from the top of the decarboxylation tower 6 for making sulfonic acid. The rich liquid converging downward in the decarboxylation tower 6 is suctioned by the first deammoniation water pump 12. Part of it is input into the volatile ammonia tower 7 of the composite deammoniation tower from the liquid inlet end at the upper part of the volatile ammonia tower 7 of the composite deammoniation tower, and the other part is cooled by the first cooler 15 and then respectively input into the second liquid spraying port above the interior of the desulfurization tower 1 and the second liquid spraying port above the interior of the desulfurization and deammoniation dual-purpose tower 2; After the rich liquid input into the volatile ammonia tower 7 of the composite deammoniation tower is mixed with steam, the alkaline gas carried upward is input into the fixed ammonium tower 8 of the composite deammoniation tower from the gas inlet end at the lower part of the fixed ammonium tower 8 of the composite deammoniation tower through the gas transmission pipe from the gas outlet end at the upper part. The rich liquid converging downward is suctioned by the second deammoniation water pump 13. Part of it is input into the fixed ammonium tower 8 of the composite deammoniation tower from the liquid inlet end at the upper part of the fixed ammonium tower 8 of the composite deammoniation tower, and the other part is respectively connected to the first liquid spraying port above the interior of the desulfurization and deammoniation dual-purpose tower 2, the second liquid spraying port above the interior of the desulfurization tower 1, and the liquid spraying port above the interior of the deammoniation tower 3 through the liquid transmission pipe in series with the second cooler 16; The alkaline gas carried upward in the fixed ammonium tower 8 of the composite deammoniation tower is output to implement ammonia vapor decomposition, and the rich liquid converging downward in the fixed ammonium tower 8 of the composite deammoniation tower is suctioned by the ammonia distillation waste water pump 14 to implement biochemical treatment;

[0017] The process flow of this embodiment is as follows: The coke oven gas from the previous process enters the lower part of the desulfurization tower 1. After cooling and the temperature dropping to 20 - 21°C, it enters the upper part of the desulfurization tower 1 and contacts countercurrently with the mixed liquid of lean liquid and rich ammonia water to remove hydrogen sulfide in the coke oven gas. Then it enters the deammoniation tower 3 and contacts countercurrently with the deammoniated water to remove ammonia in the coke oven gas. After the coke oven gas removes hydrogen sulfide and ammonia, it enters the next process. The desulfurization and deammoniation dual-purpose tower 2 serves as the maintenance standby tower for the desulfurization tower 1 and the deammoniation tower 3.

[0018] While removing hydrogen sulfide and ammonia, the rich liquid also absorbs hydrogen cyanide, carbon dioxide, and oil substances in the coke oven gas. The rich liquid is pressurized by the rich liquid pump 9 and sent to the filter 4 to remove tar substances. After heat exchange in the rich and lean liquid heat exchanger and heating to 145°C and a pressure of 0.45 MPa by the steam reboiler, it enters the dehydrocyanation tower 5 through the second rich ammonia water pump 11. The rich liquid stays in the dehydrocyanation tower 5 for 60 minutes and undergoes a hydrolysis reaction. The equation is: HCN + 2H2O → HCOOH + NH3. After the hydrolysis reaction, the hydrogen cyanide content in the rich liquid can be reduced to less than 0.2 g / L.

[0019] The rich liquid with hydrogen cyanide removed enters the middle part of the deacidification tower 6 at a temperature of about 135°C. The deacidification tower 6 operates under a pressure of about 0.5 MPa, and direct steam heating is provided at the bottom. Acid components such as hydrogen sulfide and carbon dioxide in the rich liquid escape from the top of the deacidification tower 6 and are used to produce high-purity sulfur.

[0020] The rich liquid that has removed hydrogen sulfide has actually become lean liquid. The lean liquid at the bottom of the deacidification tower 6 is pressurized by the first deammoniation water pump 12. Part of it is cooled to 22°C by the first cooler 15 and enters the desulfurization tower 1 for recycling. Another part enters the composite deammoniation tower volatile ammonia tower 7 to remove volatile ammonia. After the lean liquid removes volatile ammonia, it becomes deammoniated water and is pressurized by the second deammoniation water pump 13. Part of the deammoniated water is cooled to 22°C by the second cooler 16 and enters the deammoniation tower 3 for recycling. Another part of the deammoniated water enters the composite deammoniation tower fixed ammonium tower 8 to remove fixed ammonium. The deammoniated water after removing fixed ammonium becomes wastewater and is then pressurized by the ammonia distillation wastewater pump 14 and sent for biochemical treatment.

Claims

1. A coke oven gas combined scrubbing method deamination, desulfurization and decyanation device, comprising a desulfurization tower (1), characterized in that: It also includes a desulfurization and deammoniation dual-purpose tower (2), a deammoniation tower (3), a filter (4), a decyanation tower (5), a deacidification tower (6), a composite deammoniation tower volatilization ammonia tower (7), a composite deammoniation tower fixed ammonium tower (8), a rich liquid pump (9), a first ammonia-rich water pump (10), a second ammonia-rich water pump (11), a first deammoniation water pump (12), a second deammoniation water pump (13), an ammonia evaporation wastewater pump (14), a first cooler (15) and a second cooler (16). A desulfurization tower (1), a deammoniation tower (3), a decyanation tower (5), a deacidification tower (6) and a composite deammoniation tower volatilization ammonia tower (7) are arranged in sequence, and a composite deammoniation tower fixed ammonium tower (8) is arranged on the upper part of the composite deammoniation tower volatilization ammonia tower (7); A coke oven gas inlet is provided at the bottom of the desulfurization tower (1); a gas outlet at the top of the desulfurization tower (1) is connected to a gas inlet at the bottom of a deammonification tower (3) via a gas transmission pipe; a coke oven gas discharge port is provided at the top of the deammonification tower (3); a liquid outlet at the bottom of the deammonification tower (3) is connected to a first ammonia-rich water pump (10) via a liquid transmission pipe, and then connected to a first liquid injection port at the top of the desulfurization tower (1) via the first ammonia-rich water pump (10); The liquid outlet of the lower part of the desulfurization tower (1) is connected to the liquid inlet of the filter (4) through a liquid infusion pipe connected in series with a rich liquid pump (9); the liquid outlet of the filter (4) is connected to the liquid inlet of the lower part of the decyanation tower (5) through a liquid infusion pipe connected in series with a second ammonia-rich water pump (11); a steam inlet is provided on the second ammonia-rich water pump (11); the gas outlet of the top of the decyanation tower (5) is connected to the gas inlet of the upper part of the deacidification tower (6) through a gas infusion pipe; the lower part of the decyanation tower (5) is provided with a steam inlet; the top of the deacidification tower (6) is provided with an acid discharge port; the liquid outlet of the lower part of the deacidification tower (6) is connected to the liquid inlet of the upper part of the composite deamination tower volatile ammonia tower (7) through a liquid infusion pipe connected in series with a first deamination water pump (12); the liquid outlet of the lower part of the deacidification tower (6) is also connected to the second liquid spray port on the upper part of the desulfurization tower (1) through a liquid infusion pipe connected in series with a first cooler (15); and the lower part of the deacidification tower (6) is provided with a steam inlet; The gas outlet of the composite deammoniation tower (7) is connected to the gas inlet of the composite deammoniation tower fixed ammonium tower (8) through an air pipe, the liquid outlet of the composite deammoniation tower (7) is connected to the liquid inlet of the composite deammoniation tower fixed ammonium tower (8) through a liquid pipe connected in series with a second deammoniation water pump (13), the liquid outlet of the composite deammoniation tower (7) is connected to the liquid outlet of the composite deammoniation tower fixed ammonium tower (8) through a liquid pipe connected in series with a second deammoniation water pump (13) and a second cooler (16), and then connected to the liquid injection port at the top of the deammoniation tower (3), the lower part of the composite deammoniation tower (7) is provided with a steam inlet, and the liquid discharge port of the composite deammoniation tower fixed ammonium tower (8) is connected in series with an ammonia wastewater pump (14).

2. The coke oven gas combined scrubbing method deamination, desulfurization and decyanation device as claimed in claim 1, characterized in that: It also includes a desulfurization and deamination dual-purpose tower (2), The desulfurization and deamination dual-purpose tower (2) is arranged between the desulfurization tower (1) and the deamination tower (3); The gas outlet at the top of the desulfurization tower (1) is connected to the gas inlet at the bottom of the desulfurization and deammoniation tower (2) through a gas pipeline, the gas outlet at the top of the desulfurization and deammoniation tower (2) is connected to the gas inlet at the bottom of the deammoniation tower (3) through a gas pipeline, and the liquid outlets at the bottom of the desulfurization and deammoniation tower (2) and the deammoniation tower (3) are connected to the first ammonia-rich water pump (10) through liquid pipelines respectively; The liquid outlet at the lower part of the deacidification tower (6) is respectively connected to the second liquid injection port at the upper part of the desulfurization tower (1) and the second liquid injection port at the upper part of the desulfurization and deammoniation dual-purpose tower (2) through a liquid infusion pipe connected in series with the first cooler (15), and a steam inlet is provided at the lower part of the deacidification tower (6); The liquid outlet at the bottom of the composite deamination tower volatilization ammonia tower (7) is connected to the first liquid injection port at the top of the desulfurization and deamination dual-purpose tower (2) and the liquid injection port at the top of the deamination tower (3) through a liquid infusion pipe connected in series with a second deamination water pump (13) and a second cooler (16).

3. The method for using the coke oven gas combined scrubbing deamination, desulfurization and decyanation device as claimed in claim 1, characterized in that: Follow the steps below to implement: The coke oven gas is input into the lower section of the desulfurization tower (1) from the coke oven gas inlet at the lower part of the desulfurization tower (1), and the temperature is reduced to 20°C to 21°C after cooling. After desulfurization in the desulfurization tower (1), the coke oven gas is output from the top gas outlet, and the rich liquid is collected in the lower section; The desulfurized coke oven gas is fed into the lower section of the deamination tower (3) from the gas inlet at the lower part of the deamination tower (3). After deamination in the deamination tower (3), the coke oven gas is discharged from the coke oven gas discharge port at the top. The rich liquid in the lower section of the deamination tower (3) is sucked by a first ammonia-rich water pump (10) and input into a first liquid injection port at the top of the desulfurization tower (1); The rich liquid in the lower section of the desulfurization tower (1) is pumped to the filter (4) by the rich liquid pump (9) for filtration, and then mixed with steam in the second rich ammonia water pump (11). The second rich ammonia water pump (11) pumps the rich liquid from the lower liquid inlet end of the decyanation tower (5) into the lower section of the decyanation tower (5). After mixing with steam in the decyanation tower (5), the rich liquid is pumped from the gas outlet end at the top through the gas pipeline and the gas inlet end at the upper part of the deacidification tower (6) into the deacidification tower (6) and mixed with steam. The acidic gas escaping upward in the deacidification tower (6) is discharged from the top of the deacidification tower (6). The rich liquid collected downward in the deacidification tower (6) is pumped by the first deamination water pump (12). A portion of the rich liquid is pumped into the composite deamination tower volatilization tower (7) from the liquid inlet end at the upper part, and the other portion is cooled by the first cooler (15) and then pumped into the second liquid injection port at the upper part of the desulfurization tower (1). After the rich liquid input into the composite deamination tower volatile ammonia tower (7) is mixed with steam, the alkaline gas escaping upward is input into the composite deamination tower fixed ammonium tower (8) from the upper gas outlet through the gas transmission pipe via the lower gas inlet of the composite deamination tower fixed ammonium tower (8), and the rich liquid collected downward is sucked by the second deamination water pump (13), a part of which is input into the composite deamination tower fixed ammonium tower (8) from the upper liquid inlet of the composite deamination tower fixed ammonium tower (8), and the other part is connected to the liquid spray port at the upper part of the deamination tower (3) through the liquid transmission pipe connected in series with the second cooler (16); The alkaline gas escaping upwards in the fixed ammonium tower (8) of the composite deammoniation tower is output to implement ammonia vapor decomposition, and the rich liquid collected downwards in the fixed ammonium tower (8) of the composite deammoniation tower is sucked by the ammonia wastewater pump (14) to implement debiochemical treatment.

4. The method for using the coke oven gas combined scrubbing deamination, desulfurization and decyanation device as claimed in claim 2, characterized in that: Follow the steps below to implement: The coke oven gas is input into the lower section of the desulfurization tower (1) from the coke oven gas inlet at the lower part of the desulfurization tower (1), and the temperature is reduced to 20°C to 21°C after cooling. After desulfurization in the desulfurization tower (1), the coke oven gas is output from the top gas outlet, and the rich liquid is collected in the lower section; The desulfurized coke oven gas is fed into the lower section of the desulfurization and deammoniation dual-purpose tower (2) from the gas inlet at the lower part of the desulfurization and deammoniation dual-purpose tower (2). After desulfurization and deammoniation in the desulfurization and deammoniation dual-purpose tower (2), the coke oven gas is output from the gas outlet at the top, and the rich liquid is collected in the lower section. The desulfurized and deammonified coke oven gas is fed into the lower section of the deammonification tower (3) from the gas inlet at the lower part of the deammonification tower (3). After deammonification in the deammonification tower (3), the coke oven gas is discharged from the coke oven gas discharge port at the top. The rich liquid in the lower sections of the desulfurization and deammonification dual-purpose tower (2) and the deammonification tower (3) is pumped by a first ammonia-rich water pump (10) and input into a first liquid injection port at the top of the desulfurization tower (1); The rich liquid in the lower section of the desulfurization tower (1) is pumped to the filter (4) by the rich liquid pump (9) for filtration, and then mixed with steam in the second rich ammonia water pump (11). The rich liquid is pumped by the second rich ammonia water pump (11) from the liquid inlet end at the lower part of the decyanation tower (5) to the lower section of the decyanation tower (5). After being mixed with steam in the decyanation tower (5), the rich liquid is input into the deacidification tower (6) from the gas outlet end at the top through the gas transmission pipe and the gas inlet end at the upper part of the deacidification tower (6) to mix with steam. The acidic gas escaping upward is discharged from the top of the deacidification tower (6), and the rich liquid collected downward in the deacidification tower (6) is sucked by the first deamination water pump (12). A part of it is input into the composite deamination tower volatilization tower (7) from the liquid inlet end at the top of the composite deamination tower volatilization tower (7), and the other part is cooled by the first cooler (15) and then respectively input into the second liquid injection port at the top of the desulfurization tower (1) and the second liquid injection port at the top of the desulfurization and deamination dual-purpose tower (2); After the rich liquid input into the composite deamination tower volatile ammonia tower (7) is mixed with steam, the alkaline gas escaping upward is input into the composite deamination tower fixed ammonium tower (8) from the upper gas outlet through the gas transmission pipe via the lower gas inlet of the composite deamination tower fixed ammonium tower (8), and the rich liquid collected downward is sucked by the second deamination water pump (13), a part of which is input into the composite deamination tower fixed ammonium tower (8) from the upper liquid inlet of the composite deamination tower fixed ammonium tower (8), and the other part is respectively connected to the first liquid injection port at the upper part of the desulfurization and deamination dual-purpose tower (2) and the liquid injection port at the upper part of the deamination tower (3) through the liquid transmission pipe connected in series with the second cooler (16); The alkaline gas escaping upwards in the fixed ammonium tower (8) of the composite deammoniation tower is output to implement ammonia vapor decomposition, and the rich liquid collected downwards in the fixed ammonium tower (8) of the composite deammoniation tower is sucked by the ammonia wastewater pump (14) to implement debiochemical treatment.

5. The method for using the coke oven gas combined scrubbing deamination, desulfurization and decyanation device as claimed in claim 3 or 4, characterized in that: The rich liquid stays in the decyanation tower (5) for 10 minutes to 70 minutes, the operating temperature in the decyanation tower (5) is 135° C. to 180° C., and the operating pressure is 0.41 MPa to 0.8 MPa; The operating temperature in the deacidification tower (6) is 129°C to 180°C, and the operating pressure is 0.3MPa to 0.8MPa.

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