CN101333464A

CN101333464A - Desulphurization process by vacuum ammonia method

Info

Publication number: CN101333464A
Application number: CNA2008101453997A
Authority: CN
Inventors: 马永伟; 李洪钧; 张继明; 华祥; 顾兴林; 魏盼冬; 刘向阳
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-08-04
Filing date: 2008-08-04
Publication date: 2008-12-31
Anticipated expiration: 2028-08-04
Also published as: CN101333464B

Abstract

The invention provides a novel process for removing ammonia, H2S and HCN in coke-oven gas in the coking industry, comprising: taking ammonia in coke-oven gas and the residual ammonia water as an alkali source to have reaction with H2S and HCN in the coke-oven gas, then carrying out the resolution in a regeneration tower, removing ammonia in the obtained mixed gas by a saturex firstly, and producing elemental sulfur by the residual sour gas in a Claus furnace. The process is characterized in that: a rich liquid is obtained by utilizing the strong ammonia water obtained by ammonia in the coal gas to have reaction with H2S and HCN in the coal gas under the vacuum state, the tower bottom takes the sensible heat of flue waste gas as a heat source, the resolution is implemented in the regeneration tower under the negative pressure, and the obtained barren solution on the tower bottom is used for rewashing the ammonia. The process has advantages of simple technique, low running cost, investment saving, and high ammonia, H2S and HCN removal efficiency, and is an innovation of ammonia, H2S and HCN removing process in coal gas for coke plants.

Description

Desulphurization process by vacuum ammonia

Affiliated technical field

The invention provides a kind of be widely used in ammonia, H in the coking industry coal gas ₂S and HCN remove complete processing.

Background technology

In the coking production process, contain ammonia, H in the coal gas of generation ₂Gas such as S and HCN.Ammonia is serious to equipment corrosion, H ₂S can produce SO when together burning with coke-oven gas ₂Atmosphere pollution, and HCN is hypertoxic gas, therefore when utilizing coke-oven gas to carry out the product deep processing, must remove these gases, and H in the coal gas ₂Can the height of S content be to weigh a steel mill process the rigid index of high-quality steel, if removed the above-mentioned several gases in the coal gas, not only solved above-mentioned several problem, and can increase benefit for enterprise simultaneously.If for example can the ammonia in the coal gas be reclaimed, can produce sulfuric acid or dense ammonium water, when chemical fertilizer is used.If can remove the H in the coal gas ₂S can produce the simple substance elementary sulfur.And present ammonia, the H of removing ₂Several technologies of S and HCN are not complex process, are exactly that investment is too high, and running cost is too high, and removal efficiency is too low, the product sulfur value of production low (because of purity not high), or absorption agent is poisonous etc., does not still solve question of substance.

Summary of the invention

The invention provides the new process for processing that a kind of coking industry removes ammonia in the coke-oven gas, sulphur hydrogen and prussic acid, the problems such as sulphur poor quality of solved traditional technology energy consumption height, complex process, absorption agent is poisonous, removal efficiency is low, producing.

Technical scheme of the present invention is a coal gas through behind the electrical tar precipitator, enters Ammonic washing tower with the greedy liquid of remained ammonia and regenerator column bottom after the supercooler cooling and absorbs ammonia in the coal gas, and the strong aqua 2/3rds of gained is used for absorbing the H of coal gas bottom the Ammonic washing tower ₂S and HCN enter ammonia still after the wastewater heat exchange device heat exchange at the bottom of 1/3rd processes and the ammonia still, under negative pressure state, make the ammonia volatilization in the strong aqua, enter desulfuration absorbing tower again after ammonia cools off through condensed device, vacuum pump, ammonia cooler and absorb H ₂S and HCN, a circulation spray wine pump has been installed at the desulfuration absorbing tower middle part, after the rich solution process and the greedy rich solution heat exchange at the bottom of the regenerator column that the desulfuration absorbing tower bottom obtains, enters regenerator column, under negative pressure state, makes ammonia, H in the rich solution ₂S and HCN resolve, and after the gas mixture process condensed device refrigerated separation, to saturex, remove the ammonia in the gas mixture by the vacuum pump positive delivery, and the acid gas that saturex comes out after the supercooler cooling, enters the acid gas separator again, enters next procedure.The waste water of ammonia still bottom and with the cyclic ammonia water heat exchange after and return tower after the greedy liquid of regenerator column bottom and the stack gas heat exchange at the bottom of, for two towers provide sensible heat.Its principal character is:

After a, this technology are placed on electrical tar precipitator;

B, thionizer have added a circulation and have sprayed washing pump;

C, used alkali source are from the ammonia in coal gas and the remained ammonia;

D, ammonia still and regenerator column are in negative pressure state;

E, ammonia still bottom sensible heat provide with cyclic ammonia water, and regenerator column bottom sensible heat provides with coke oven flue waste gas;

F, ammonia still, regenerator column inside are filling-material structure;

G, ammonia, H ₂S and HCN mixed gas process saturex are removed the ammonia in the mixed gas.

Vacuum ammonia process of the present invention removes H ₂The S complete processing after said this technology is placed on electrical tar precipitator, is meant coke-oven gas through primary cooler and electrical tar precipitator, gas temperature is cooled down (dropping to 23 ℃ by 80 ℃) and after tar impurity removes, has guaranteed that coal gas removes H in thionizer ₂The efficient of S and HCN and the obstruction that has reduced later process are simultaneously than cooling tower of HPF method minimizing traditionally; Said thionizer has added a circulation spray pump, is meant at thionizer middle part, and in order to add systemic circulation sprinkling amount, therefore most H ₂S and HCN are absorbed at the thionizer middle part; Said all alkali source from the ammonia in coal gas and the remained ammonia refer to the greedy liquid that comes out the free regenerator column of absorption agent bottom through greedy rich solution interchanger after, again through after the greedy liquid water cooler cooling, contact with coal gas with remained ammonia adverse current in Ammonic washing tower of coming, the ammonia that absorbs in the coal gas is H in the coal gas ₂S and HCN reaction provide alkali source, and in thionizer following reaction take place:

NH ₄OH+H ₂S＝NH ₄HS+H ₂O

NH ₄OH+NH ₄HS＝(NH ₄) ₂S+H ₂O

NH ₄OH+HCN＝NH ₄CN+H ₂O

Thereby overcome vacuum Na ₂CO ₃And K ₂CO ₃Arts demand replenishes this problem of alkali source; Move under the subatmospheric negative pressure state of said ammonia still process and regenerator column, tower top pressure is-83.1P _a, tower bottom pressure is-81.1P _a, at this moment following reaction takes place 60 ℃ of boilings in liquid at the bottom of the tower:

(NH ₄) ₂S+H ₂O＝NH ₄OH+NH ₄HS

NH ₄HS+H ₂O＝NH ₄OH+H ₂S↑

NH ₄CN+H ₂O＝NH ₄OH+HCN↑

NH ₄ON＝NH ₃↑+H ₂O；

The said cyclic ammonia water sensible heat that utilizes is ammonia still and utilize coke oven flue waste gas sensible heat to provide the evaporation thermal source for regenerator column, after being meant that ammonia still and regenerator column are through the vacuum pump decompression, the boiling point of liquid of tower bottom has reduced, therefore cyclic ammonia water that can be by being sent to coke oven and provide from the come out sensible heat of stack gases of main flue, the liquid of two tower bottoms boosts through the pump that boils again, the ammonia still bottom liquid heats up back and regenerator column bottom liquid after chimney heat exchanger and stack gases heat exchange intensification through taking device and cyclic ammonia water heat exchange heat again, return into two tower bottoms, thereby cancelled the steam resource consumption; Said ammonia still and regenerator column inside are filling-material structure, are meant that this technology strong aqua all is to move under the low-temp low-pressure at ammonia still and absorption rich solution at regenerator column, have changed traditional metal tray structure, and available general filler replaces; Said ammonia, H ₂O and HCN mixed gas process saturex are removed the ammonia of mixed gas, are meant the ammonia, the H that process ₂Following reaction takes place through saturex in S and HCN:

NH ₄OH+H ₂SO ₄＝NH ₄HSO ₄+H ₂O

NH ₄HSO ₄+ NH ₄OH=(NH ₄) ₂SO ₄+ H ₂O removes the ammonia in the mixed gas.

The present invention is to the traditional deamination of coking industry, H ₂S and HCN technology are bold in innovation, and have proposed new technical scheme, have cancelled steam, and the consumption of alkali source and other absorption agent makes the investment height that exists in original technology, running cost height, situation that removal efficiency is low obtain radical change.

Fig. 1, the 2nd, vacuum ammonia process removes H ₂The Figure of description of S

Embodiment

Among Fig. 2: 1, desulfuration absorbing tower, 2, Ammonic washing tower, 3, ammonia still, 4, regenerator column, 5, saturex, 6, the acid vapour separator, 7, the circulation spray pump, 8, the rich solution pump, 9, the strong aqua pump, 10, the remained ammonia water cooler, 11, greedy liquid pump, 12, pump again boils, 13, reboiler, 14, the pump that boils again, 15, chimney, 16, ammonia vapour water cooler, 17, vacuum pump, 18, ammoniacal liquor flow quantity self-adjusting valve, 19, water sealed tank, 20, ammonia vapour condensed device, 21, the mixed steam condensed device, 22, water sealed tank, 23, vacuum pump, 24, acid vapour water cooler, 25, the distilled ammonia wastewater pump, 26, the ammoniacal liquor interchanger, 27, greedy rich solution interchanger.28, greedy liquid water cooler, 29, the stack gas interchanger, 30 vacuum fans, 31, mother liquor tank, 32, little mother liquor pump

Patent of the present invention is implemented by following concrete steps: per hour to handle coal gas is 70,000 m ³Be example: the temperature of regenerator column (4) bottom is that 60 ℃, flow are 60m ³/ h contains ammonia and pressurizes through greedy liquid pump (11) at the greedy liquid of 0.03g/L, after greedy rich solution interchanger (27) heat exchange to 46 ℃-48 ℃, deliver to after greedy liquid water cooler (28) (water at low temperature) heat exchange 23 ℃-25 ℃ and enter Ammonic washing tower (2) epimere, with on the dilute NaOH solution brought in and the stage casing temperature of coming be that 45 ℃-50 ℃ and flow are 30m ³, reduce to after 23 ℃-25 ℃ remained ammonia converges through remained ammonia water cooler (10) (water at low temperature), (2) and coal gas counter current contact from desulfuration absorbing tower (1) absorb the ammonia in the coal gas in Ammonic washing tower, and the Ammonic washing tower bottom rate is at 90m ³/ h (temperature is at 28 ℃-30 ℃), contain the strong aqua of ammonia at 8g-10g/l, get to desulfuration absorbing tower (1) through 2/3 of strong aqua pump (9) flow, be warming up to 38 ℃-40 ℃ behind the 1/3 process ammoniacal liquor interchanger (26) of flow, enter ammonia still (3) by flow quantity self-adjusting valve (18), 60 ℃ of distilled ammonia wastewaters of ammonia still bottom are sent to biochemistry (3) after delivering to ammoniacal liquor interchanger (26) heat exchange to 45 ℃-48 ℃ after by distilled ammonia wastewater pump (25) pressurization, the ammonia vapour that comes out in the ammonia still top is through ammonia vapour condensed device (20) (recirculated water) heat exchange to 35 ℃-40 ℃, be pressurized to 25kPa-30kPa by vacuum pump (17), flow is 300m ³/ h-350m ³/ h ammonia is delivered to ammonia cooler (16) (water at low temperature) and is reduced to 23 ℃-25 ℃, enters the flushing liquor that (1) stage casing, thionizer absorption tower and circulation spray pump (7) come and converges sprinkling, and from the coal gas counter current contact behind the electrical tar precipitator, absorbs the H in the coal gas ₂S and HCN, after the rich solution of desulfuration absorbing tower (1) bottom pressurizes through rich solution pump (8), be delivered to greedy rich solution interchanger (27) temperature and be raised to 38 ℃-40 ℃ by 25 ℃, enter regenerator column (4), the mixing gas that comes out in regenerator column (4) top cools to (35 ℃-40 ℃) through mixed steam condensed device (21) (recirculated water), be pressurized to 20kPa-30kPa by vacuum pump (23), flow is 1200m ³/ h-1400m ³/ h mixing gas is delivered to saturex (5), contacts the ammonia vapour of removing in the mixing with the dilute sulphuric acid of saturex (5) rice, and the temperature of coming out from saturex is 50 ℃-55 ℃, and flow is 360m ³/ h-400m ³The sour vapour of/h ℃-28 ℃ enters sour vapour separator (6) with sour vapour water cooler (24) (water at low temperature) heat exchange to 25, divides vapour to enter next procedure from the acid gas that device (6) comes out from acid.

Make ammonia still, regeneration overhead maintenance-83.1KPa pressure by vacuum pump (17,23), maintenance-81.1KPa pressure at the bottom of the tower, liquid is about 60 ℃ of boilings at the bottom of the tower, and the liquid that the gas of generation and cat head get off contacts in that filling surface is reverse, and the gas in the liquid is resolved to come out; The thermal source of ammonia still (3) bottom is provided by the about 75 ℃ cyclic ammonia water that is sent to coke oven, and ammonia still (3) bottom liquid is by the pump that boils again (12) pressurization, according to 700m at the bottom of the tower ³/ h internal circulating load is returned the ammonia still bottom after being warming up to 70 ℃-72 ℃, and the thermal source of regenerator column (4) bottom is provided for 360 ℃ of stack gases sensible heats by the temperature of coming out from the coke oven main flue, and regenerator column (4) bottom liquid is by the pump that boils again (14) pressurization, according to 2800m at the bottom of the tower ³After/h internal circulating load process stack gas interchanger (29) and the stack gases heat exchange, after rising to 70 ℃-72 ℃, temperature returns regenerator column (4) bottom; After the flue waste vapour passed through stack gas interchanger (29) by 360 ℃, temperature was reduced to 80 ℃, is sent to chimney (15) by vacuum fan (30).

The condensing water that ammonia vapour condensed device (20) is condensed enters water sealed tank (19), the condensing water that mixed steam condensed device (21) is condensed enters water sealed tank (22), water sealed tank inside is provided with fluid-tight, and the liquid of water sealed tank (19,22) can be squeezed into system by greedy liquid pump import and circulate; The liquid that acid vapour separator (6) separates flows into mother liquor tank (31), regularly uses little mother liquor pump (32) to squeeze in the saturex (5) and utilizes.

Claims

1, vacuum ammonia process removes H in a kind of coking industry coke-oven gas ₂S and HCN add technology, its principal character is: part is washed the strong aqua that comes by Ammonic washing tower enter thionizer to absorb H2S and the HCN in the coal gas, remaining strong aqua is under vacuum negative pressure condition, and the ammonia vapour that obtains resolving acquisition at ammonia still is sent to the H that thionizer is used for further absorbing coal gas ₂S and HCN; The rich solution that obtains in the thionizer bottom is sent to regenerator column, obtains resolving under vacuum negative pressure condition, and the mixed steam elder generation process saturex of gained is removed ammonia vapour wherein, and remaining sour gas is sent to next procedure.

2, remove H according to the described vacuum ammonia process of claim 1 ₂The complete processing of S and HCN is characterized in that: utilize ammonia in the coal gas as alkali source, saved vacuum carbonate and removed H ₂S and HCN complete processing add alkali source, reduced the greedy liquid regenerated steam consumption of HPF method again, and the use of catalyzer.

3, remove H according to the described vacuum ammonia process of claim 1 ₂The complete processing of S and HCN is characterized in that: the evaporation thermal source is provided by the sensible heat of cyclic ammonia water at the bottom of the ammonia still; Evaporation thermal source at the bottom of the regenerator column is provided by the sensible heat of coke oven flue waste gas.

4, remove H according to the described vacuum ammonia process of claim 1 ₂S and HCN add technology, it is characterized in that: added a circulation spray pump at the middle part of thionizer, be used for improving the H of coal gas ₂The removal efficiency of S and HCN.

5, remove H according to the described vacuum ammonia process of claim 1 ₂The complete processing of S and HCN is characterized in that: utilize vacuum pump that ammonia still and regenerator column are reduced pressure, and pressure reduces to-and 81.1Kpa is to-83.1Kpa, and regenerator column is worked under vacuum, low temperature environment.

6, remove H according to the described vacuum ammonia process of claim 1 ₂The complete processing of S and HCN is characterized in that: be placed on this technology behind the electric coke catcher and gas blower before.

7, remove H according to the described vacuum ammonia process of claim 1 ₂The complete processing of S and HCN is characterized in that: used ammonia still and regenerator column are inner to be the material filling type structure.