JP2015229736A - Desulfurization device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desulfurization device excellent in desulfurization capacity.SOLUTION: Provided is a desulfurization device 1 comprising: a desulfurization tower 20 where a coke oven gas G1 and an absorption solution S2 are brought into counter flow contact to absorb a sulfide in the coke oven gas G1 in the absorption solution S2; and a regeneration tower 30 where an oxygen-containing gas is fed to the absorption solution S2 exhausted from the desulfurization tower 20 to oxidize the sulfide, and at least a part of the absorption solution S2 is circulated around the desulfurization tower 20. The desulfurization tower 20 has a plurality stages of absorption layers 26. Each absorption layer 26 has a thickness of 200 to 1,500 mm, temporarily holds the absorption solution S2 so as to be introduced from the upper part to the lower part, and further passes the coke oven gas G1 from the lower part to the upper part. The generation tower 30 has a mixing tank 40. The mixing tank 40 receives the absorption solution S2 from the desulfurization tower 20, further receives the oxygen-containing gas to compose a gas-liquid mixed fluid, and rises the gas-liquid mixed fluid while circulating the gas-liquid mixed fluid.

Description

  The present disclosure relates to a desulfurization apparatus.

  Coke oven gas generated when carbon is distilled to produce coke can be used as fuel. Since the coke oven gas contains sulfides, it generates sulfur oxides when burned, which may affect the environment. Therefore, prior to using the coke oven gas as a fuel, the sulfide in the coke oven gas is removed. For removal of sulfides, for example, as shown in Patent Document 1, a desulfurization apparatus is used that absorbs sulfides in coke oven gas by absorbing the coke oven gas and the absorbing solution by countercurrent contact. .

China Utility Model No. 2010880463U Specification

  An object of this indication is to provide the desulfurization apparatus excellent in the desulfurization capability.

  The desulfurization apparatus according to the present disclosure includes a desulfurization tower that absorbs sulfide in the coke oven gas into the absorption liquid by contacting the coke oven gas and the absorption liquid countercurrently, and an oxygen in the absorption liquid discharged from the desulfurization tower. And a regenerating tower that circulates at least a part of the absorption liquid to the desulfurization tower, the desulfurization towers are provided so as to be spaced apart from each other and lined up and down, It has a thickness of 200 to 1500 mm, and temporarily holds the absorbing liquid and guides it from top to bottom, and has a plurality of absorbing layers through which coke oven gas passes from bottom to top. In addition to receiving the absorbing liquid from the gas, the gas-liquid mixed fluid is formed by receiving a gas containing oxygen, and the mixing tank raises the gas-liquid mixed fluid while swirling.

  When the thickness of the absorption layer of the desulfurization tower is too small, the contact efficiency between the coke oven gas and the absorption liquid in the absorption layer becomes insufficient. On the other hand, if the thickness of the absorption layer is too large, the air permeability of the absorption layer decreases due to the accumulation of solid sulfur generated by the oxidation reaction in the regeneration tower, and the contact efficiency between the coke oven gas and the absorption liquid decreases. If the thickness of the absorption layer is 200 mm or more, sufficient contact efficiency between the coke oven gas and the absorption liquid can be obtained. If the thickness of the absorption layer is 1500 mm or less, the generated solid sulfur is swept away by the absorption liquid, so that a reduction in contact efficiency between the coke oven gas and the absorption liquid due to the accumulation of solid sulfur is suppressed. For this reason, sufficient contact efficiency of coke oven gas and absorption liquid is maintained for a long term because the thickness of an absorption layer is 200-1500 mm.

  In the regeneration tower, gas containing oxygen is mixed into the absorbing liquid to form a gas-liquid mixed fluid, and the gas-liquid mixed fluid rises while swirling in the mixing tank. Thereby, the fluidity of the whole gas-liquid mixed fluid accommodated in the mixing tank is obtained, so that the stirring and mixing of the oxygen-containing gas and the absorbing liquid becomes quick and uniform. For this reason, the ability of the absorbing liquid to absorb sulfide (hereinafter referred to as “absorbing ability of the absorbing liquid”) is sufficiently restored.

  In this way, sufficient contact efficiency of coke oven gas and absorption liquid is maintained in the desulfurization tower for a long time, and the absorption capacity of the absorption liquid is sufficiently restored in the regeneration tower, so that high desulfurization performance is achieved for a long time. Can be maintained. Therefore, the desulfurization apparatus according to the present disclosure is excellent in desulfurization performance.

  A pre-cooling tower for cooling the coke oven gas by countercurrent contact between the coke oven gas and the coolant containing tar with a content of 1 to 6% at the front stage of the desulfurization tower is further provided. May be.

  The absorption capacity of the absorbent tends to improve as the temperature of the coke oven gas decreases. For this reason, the desulfurization capability of coke oven gas improves by cooling coke oven gas in the front | former stage of a desulfurization tower. Since the cooling liquid of the precooling tower contains tar, even if naphthalene in the coke oven gas is precipitated by cooling, the precipitated naphthalene is absorbed by the tar and is washed away together with the cooling liquid. For this reason, accumulation of naphthalene in the precooling tower is suppressed, and the ability of the precooling tower to cool the coke oven gas is maintained for a long time. Therefore, the desulfurization capacity can be improved by cooling the coke oven gas, and the improvement effect can be maintained for a long time.

  The mixing tank includes a tank main body that stores the gas-liquid mixed fluid, and an injection pipe that is provided in a lower portion of the tank main body and receives a gas containing an absorbing liquid and oxygen and injects the gas-liquid mixed fluid into the tank main body. The injection pipe has a plurality of pipes arranged in the jet direction of the gas-liquid mixed fluid, and is configured to suck the surrounding fluid between the pipe bodies by the ejector effect, and the gas-liquid mixing You may arrange | position so that a swirling flow may be formed in a tank main body by the injection of a fluid.

  In this case, since the swirl flow is formed in the tank body by the jet flow of the gas-liquid mixed fluid, the gas-liquid mixed fluid rises while swirling in the tank body. Thereby, the fluidity of the gas-liquid mixed fluid is obtained, so that the stirring and mixing of the gas containing oxygen and the absorbing liquid becomes quick and uniform, and the oxidation reaction proceeds efficiently. Part of the gas-liquid mixed fluid injected into the tank body is sucked into the injection pipe again due to the ejector effect. The gas to be mixed is sufficiently mixed in the gas-liquid mixed fluid. Therefore, the absorption capacity of the absorbent can be recovered efficiently and reliably. Note that swirling the gas-liquid mixed fluid using the jet flow of the gas-liquid mixed fluid also contributes to simplification of the structure of the mixing tank.

  The tank body has a cylindrical side wall, and the height of the side wall is not more than twice the inner diameter of the side wall and may be 1 m or more.

  When the depth of the gas-liquid mixed fluid accommodated in the tank body is too small, the oxidation rate of the sulfide in the absorbing liquid tends to be remarkably reduced. If the height of the side wall is increased, the depth of the gas-liquid mixed fluid is also increased, so that the oxidation rate of sulfide in the absorbing liquid is improved, but the energy consumption for flowing the absorbing liquid is also increased. Furthermore, if the height of the side wall is increased and the depth of the gas-liquid mixed fluid is increased too much, the improvement in the oxidation rate will slow down, which is uneconomical. If the height of the side wall is 1 m or more, the oxidation rate of the sulfide in the absorbing liquid can be secured. If the height of the side wall is not more than twice the inner diameter of the side wall, an oxidation ability commensurate with the energy consumption can be obtained. Therefore, if the height of the side wall is not more than twice the inner diameter of the side wall and is 1 m or more, the oxidation ability can be secured with high energy efficiency.

  The regeneration tower further includes a deaeration tank that is provided so as to surround the mixing tank, is configured to receive the gas-liquid mixed fluid discharged from the mixing tank, and separate and discharge it into an absorbing liquid and a gas. Also good.

  In this case, since the gas is removed from the absorbing liquid S2, the occurrence of cavitation in the pump P2 that pumps the absorbing liquid S2 is suppressed. Thereby, the absorption liquid S2 can be circulated stably between the desulfurization tower 20 and the regeneration tower 30. Therefore, the desulfurization capacity can be maintained more reliably.

  According to the present disclosure, it is possible to provide a desulfurization apparatus having excellent desulfurization capability.

It is a schematic diagram which shows schematic structure of a desulfurization apparatus. It is sectional drawing of a pre-cooling tower. It is sectional drawing of a desulfurization tower. It is sectional drawing of a regeneration tower. It is a top view of a regeneration tower. It is a schematic diagram which expand | deploys and shows a deaeration tank. It is a graph which shows the relationship between the depth of the gas-liquid mixed fluid collected in the tank main body, and an oxygen utilization factor.

  Hereinafter, embodiments will be described in detail with reference to the drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant description is omitted. A desulfurization apparatus 1 shown in FIG. 1 is an apparatus for removing sulfides in coke oven gas, and includes a precooling tower 10, a desulfurization tower 20, and a regeneration tower 30.

  The pre-cooling tower 10 cools the coke oven gas by bringing the coke oven gas and the coolant containing tar into countercurrent contact with each other in the previous stage of the desulfurization tower 20. The desulfurization tower 20 makes the absorbent absorb the sulfide in the coke oven gas by bringing the coke oven gas and the absorbent into countercurrent contact. The regeneration tower 30 supplies a gas containing oxygen to the absorption liquid discharged from the desulfurization tower 20 to oxidize sulfides, and returns at least a part of the absorption liquid to the desulfurization tower 20.

  As shown in FIG. 2, the precooling tower 10 includes a gas inlet 11, a gas outlet 12, a coolant inlet 13, a distributor 14, a coolant outlet 15, and a plurality of cooling layers 16. Have. FIG. 2 shows a case where the cooling layer 16 has three stages, but the number of stages of the cooling layer 16 is not particularly limited and can be changed as appropriate.

  The gas inlet 11 is provided in the lower part of the side wall of the precooling tower 10, and receives coke oven gas G1. The gas delivery port 12 is provided at the top of the precooling tower 10 and sends out the coke oven gas G1 that has risen in the precooling tower 10.

  The coolant inlet 13 is provided in the upper part of the side wall of the precooling tower 10, and receives the coolant S1 containing tar. The coolant S1 is water containing tar, for example. The distributor 14 is provided in the upper part of the precooling tower 10 and is connected to the coolant inlet 13. The distributor 14 discharges the cooling liquid S1 received from the cooling liquid receiving port 13 downward from the plurality of discharge ports 14a. The cooling liquid delivery port 15 is provided below the gas receiving port 11 at the lower part of the side wall of the pre-cooling tower 10, and sends out the cooling liquid S 1 that has dropped to the bottom of the pre-cooling tower 10.

  The cooling layers 16 in a plurality of stages are provided between the distributor 14 and the gas receiving port 11 in the pre-cooling tower 10 and are spaced apart from each other and arranged in the vertical direction. Each of the cooling layers 16 is provided so as to partition the inside of the precooling tower 10 up and down, temporarily holds the cooling liquid S1 and guides it from the top to the bottom, and passes the coke oven gas G1 from the bottom to the top. For this reason, the coke oven gas G1 and the coolant S1 are in countercurrent contact in the cooling layer 16. Specifically, the cooling layer 16 is filled with a large number of fillers 16a. The filler 16a is a breathable solid member made of a resin material such as polypropylene. The cooling liquid S1 is guided from the top to the bottom while being attached to the surface of the filler 16a. The coke oven gas G1 passes through the filler 16a from the bottom to the top.

  As shown in FIG. 3, the desulfurization tower 20 includes a gas inlet 21, a gas outlet 22, an absorbing liquid inlet 23, a distributor 24, an absorbing liquid outlet 25, and a plurality of stages of absorbing layers 26. Have.

  The gas inlet 21 is provided in the lower part of the side wall of the desulfurization tower 20 and receives the coke oven gas G1. The gas delivery port 22 is provided in the top part of the desulfurization tower 20, and sends out the coke oven gas G1 which raised the inside of the desulfurization tower 20.

  The absorption liquid inlet 23 is provided in the upper part of the side wall of the desulfurization tower 20, and receives the absorption liquid S2. The absorbing liquid S2 is, for example, ammonia water, and is obtained by circulating water supplied from the outside between the desulfurization tower 20 and the regeneration tower 30. That is, the water supplied from the outside absorbs ammonia in the coke oven gas G1 in the process of circulating between the desulfurization tower 20 and the regeneration tower 30 and becomes ammonia water, and functions as the absorbing liquid S2. The distributor 24 is provided in the upper part of the desulfurization tower 20 and is connected to the absorbent receiving port 23. The distributor 24 discharges the absorbing liquid S2 received from the absorbing liquid receiving port 23 downward from the plurality of discharge ports 24a. The absorption liquid delivery port 25 is provided in the lower part of the side wall of the desulfurization tower 20 and sends out the absorption liquid S2 that has dropped to the bottom of the desulfurization tower 20.

  The plurality of stages of absorption layers 26 are provided between the distributor 24 and the gas receiving port 21 in the desulfurization tower 20 and are arranged in the vertical direction. Each absorption layer 26 is provided so as to partition the inside of the desulfurization tower 20 up and down, and temporarily holds the absorption liquid S2 and guides it from the top to the bottom, and passes the coke oven gas G1 from the bottom to the top. For this reason, the coke oven gas G1 and the absorbing liquid S2 are in countercurrent contact with each other in the absorbing layer 26. Specifically, the absorbent layer 26 is filled with a large number of fillers 26a. The filler 26a is a breathable solid member made of a resin material such as polypropylene. The absorbing liquid S2 is guided from the top to the bottom while adhering to the surface of the filler 26a. The coke oven gas G1 passes through the filler 26a from the bottom to the top.

  The thickness h1 of the absorption layer 26 is 200 to 1500 mm. The number of steps of the absorption layer 26 is, for example, eight or more, but is not limited thereto. The number of stages of the absorption layer 26 should just be set more than the value which divided the countercurrent contact distance required in order to fully absorb the sulfide in coke oven gas G1 by the absorption liquid S2 by thickness h1.

  As shown in FIGS. 4 and 5, the regeneration tower 30 includes a mixing tank 40 and a deaeration tank 50.

  The mixing tank 40 receives the absorbing liquid S2 from the absorbing liquid delivery port 25 at the lower part of the desulfurization tower 20 through the communication pipe 43 and the absorbing liquid receiving port 44, and also receives a gas containing oxygen to constitute a gas-liquid mixed fluid. Then, the gas-liquid mixed fluid is raised while swirling. The gas received by the mixing tank 40 may be any gas as long as it contains oxygen. However, in order to reduce the power for supplying air to the mixing tank 40, a gas having a higher oxygen concentration may be used. desirable. As an example, it is assumed that the gas received by the mixing tank 40 is air.

  The mixing tank 40 includes a tank body 41 and six injection pipes 42. The tank body 41 has a cylindrical side wall 41a that opens upward, and accommodates the gas-liquid mixed fluid. The height h2 of the side wall 41a is not more than twice the inner diameter d1 of the side wall 41a and is not less than 1 m. That is, the depth of the tank body 41 is not more than twice the inner diameter of the tank body 41 and is 1 m or more. The height h2 of the side wall 41a (depth of the tank body 41) may be 0 to 4 m.

  The injection pipe 42 is provided in the lower part in the tank main body 41, receives the absorbing liquid S2 and air, and injects the gas-liquid mixed gas into the tank main body 41. The injection pipe 42 has a plurality of pipe bodies 42a, 42b, and 42c arranged in the jet direction of the gas-liquid mixed fluid, and sucks the surrounding fluid between the pipe bodies 42a, 42b, and 42c by the ejector effect. It is configured. The six injection pipes 42 are arranged so as to generate a swirling flow in the tank body 41 by the injection of the gas-liquid mixed fluid. Specifically, the six injection pipes 42 are arranged so as to surround the center C1 of the side wall 41a, and are arranged so as to inject the gas-liquid mixed fluid along the same turning direction RD. In addition, there is no restriction | limiting in the number of the injection pipes 42, it is not restricted to six pieces, The at least one piece should just be installed. Moreover, each injection pipe 42 is not restricted to the triple type which consists of three pipe bodies 42a, 42b, and 42c.

  The deaeration tank 50 is provided so as to surround the mixing tank 40 from the outside. The degassing tank 50 receives the gas-liquid mixed fluid continuously flowing out from the upper part of the mixing tank 40, and separates and discharges it into the absorbing liquid S2 and the gas. It is configured.

  Specifically, as shown in FIGS. 5 and 6, the deaeration tank 50 includes one dam plate 51, two partition plates 52, three partition plates 53, and an absorption liquid delivery port 54. Have The dam plate 51 and the partition plates 52 and 53 are arranged in the deaeration tank 50 so as to be aligned in the circumferential direction. The dam plate 51, the partition plate 52, and the partition plate 53 are arranged alternately. In the depth direction in the deaeration tank 50, the dam plate 51 is positioned so as to extend from the liquid level to the entire bottom surface, the partition plate 52 is positioned near the liquid level, and the partition plate 53 is positioned near the tank bottom surface. The absorption liquid delivery port 54 is provided in the lower part of the side wall of the deaeration tank 50, and sends out the absorption liquid S2 from the inside of the deaeration tank 50. The absorbing liquid delivery port 54 opens at a location adjacent to the weir plate 51. The gas-liquid mixed fluid received from the mixing tank 40 into the deaeration tank 50 is directed to the absorption liquid delivery port 54 along the circumferential direction. In the path toward the absorbing liquid delivery port 54, the gas-liquid mixed fluid alternately passes through the upper part of the partition plate 53 and the lower part of the partition plate 52, and thus repeats the vertical movement. Thereby, separation (degassing) of gas from the gas-liquid mixed fluid is promoted. That is, the gas-liquid mixed fluid is separated into the absorbing liquid S2 and the gas. The gas rises and is discharged from the liquid surface, and the sufficiently degassed absorbing liquid S2 is discharged from the absorbing liquid delivery port 54.

  Thus, sending out absorption liquid S2 after deaeration from absorption liquid delivery outlet 55 contributes to preventing cavitation in pump P2, as will be described later. By preventing cavitation that hinders pumping by the pump P2, the absorbing liquid S2 can be continuously and stably supplied to the desulfurization tower 20, and the desulfurization capability can be more reliably maintained.

  The deaeration tank 50 may be any type as long as the absorbing liquid S2 can be deaerated, and is not limited to the above-described configuration. For example, the number of the dam plates 51 and the partition plates 52 and 53 is not limited to the above number, and can be appropriately changed according to the size of the regeneration tower 30, the amount of the absorbing liquid to be processed, and the like.

  Returning to FIG. 1, the gas inlet 11 of the pre-cooling tower 10 is connected to a coke oven (not shown) via an air supply line L5. The gas outlet 12 of the precooling tower 10 is connected to the gas inlet 21 of the desulfurization tower 20 via an air supply line L6. The coolant inlet 13 and the coolant outlet 15 of the precooling tower 10 are connected via a liquid supply line L1, and a pump P1 is provided in the liquid supply line L1. The pump P <b> 1 pumps the cooling liquid S <b> 1 sent from the cooling liquid outlet 15 to the cooling liquid inlet 13.

  A tar introduction line L2, a drainage line L3, and a replenishment line L4 are connected to the liquid supply line L1. The tar introduction line L2 guides the tar into the liquid supply line L1 from a tar supply source (not shown). The tar introduction pipe L2 may be piped so as to guide tar generated in the coke generation process into the liquid feed pipe L1. The drainage pipe L3 discharges a part of the cooling liquid S1 in order to suppress an increase in the concentration of naphthalene in the cooling liquid S1 flowing in the liquid feeding pipe L1. The replenishment line L4 replenishes the liquid supply line L1 with the same amount of liquid as the cooling liquid S1 discharged from the drainage line L3. The liquid replenished by the replenishment line L4 is, for example, ammonia water or water.

  In addition, in the pre-cooling tower that cools the coke oven gas temperature from 50 ° C. to 35 ° C., when the tar content of the coolant S1 is less than 1%, the naphthalene absorption capacity is insufficient. The pressure loss of layer 16 tends to increase. On the other hand, when the tar content of the coolant S1 is more than 6%, the tar adheres to the filler, and the pressure loss of the cooling layer 16 tends to increase. For this reason, the amount of tar introduced from the tar introduction pipe L2 is adjusted so that the content rate of tar in the coolant S1 is 1 to 6%.

  An air introduction pipe L8 is connected to the injection pipe. The air introduction line L8 introduces air to be mixed into the absorbing liquid S2 into the injection pipe 42. The absorption liquid outlet 54 of the regeneration tower 30 is connected to the absorption liquid inlet 23 of the desulfurization tower 20 via a liquid supply line L9, and a pump P2 is provided in the liquid supply line L9. The pump P <b> 2 pumps most of the absorption liquid S <b> 2 sent from the absorption liquid outlet 54 to the absorption liquid inlet 23.

  A liquid supply line L7, a drainage line L10, and a replenishment line L11 are connected to the liquid supply line L9. The liquid supply line L7 returns a part of the absorbing liquid S2 flowing through the liquid supply line L9 to the injection pipe 42. The drainage pipe L10 discharges a part of the absorbent S2 in order to suppress an increase in the concentration of solid sulfur in the absorbent S2 flowing in the liquid feed pipe L9. The replenishment line L11 replenishes the liquid supply line L9 with the same amount of liquid as the absorption liquid S2 discharged from the drainage line L10. The liquid replenished by the replenishment line L11 is, for example, ammonia water or water.

  The coke oven gas G1 led from the coke oven side to the gas inlet 11 by the air supply line L5 is received from the gas inlet 11 into the precooling tower 10 and rises while passing through the cooling layer 16, and the gas outlet 12 Is sent from. The cooling liquid S1 introduced to the cooling liquid inlet 13 by the liquid supply pipe L1 is received into the precooling tower 10 from the cooling liquid inlet 13, falls while passing through the cooling layer 16, and is discharged from the cooling liquid outlet 15. Sent out. In the cooling layer 16, the coke oven gas G1 and the coolant S1 are in countercurrent contact with each other. Thereby, the coke oven gas G1 is cooled, and naphthalene in the coke oven gas G1 is absorbed by the tar in the coolant S1.

  The coolant S1 that has absorbed naphthalene and is sent from the coolant outlet 15 is pumped to the coolant inlet 13 side by the pump P1. The tar introduced from the tar introduction pipe L2 is mixed in the coolant S1 flowing toward the coolant inlet 13 side. A part of the coolant S1 flowing to the coolant inlet 13 side is discharged through the drain line L3. The remaining cooling liquid S1 is diluted with water or the like replenished through the replenishment line L4, and then received again from the cooling liquid inlet 13 into the precooling tower 10. In this way, a part of the coolant S1 is recycled.

  The amount of the cooling liquid S1 discharged from the drainage pipe L3 is, for example, such that the amount of naphthalene contained in the tar in the cooling liquid S1 entering the precooling tower 10 from the cooling liquid inlet 13 is equal to or lower than the saturation solubility. Set to Although the cooling liquid S1 is diluted with water or the like replenished from the replenishment line L4, since tar is introduced by the tar introduction line L2, the content of tar in the cooling liquid S1 is kept at an appropriate value. It is.

  The coke oven gas G1 guided from the precooling tower 10 to the desulfurization tower 20 by the air supply line L6 is received into the desulfurization tower 20 from the gas inlet 21 and rises while passing through the absorption layer 26, and from the gas outlet 22 Sent out. The absorbing liquid S2 guided to the absorbing liquid inlet 23 by the liquid feeding pipe L9 is received into the desulfurization tower 20 from the absorbing liquid inlet 23, falls while passing through the absorbing layer 26, and passes through the absorbing liquid outlet 25. Sent out. In the absorption layer 26, the coke oven gas G1 and the absorption liquid S2 are in countercurrent contact with each other. Thereby, the sulfide in the coke oven gas G1 is absorbed by the absorbent S2.

  Absorbing liquid S2 absorbed from the sulfide and delivered from the absorbing liquid delivery port 25 is guided into the injection pipe 42 through the liquid feeding line L7. Air is also guided into the injection pipe 42 by an air introduction pipe L8. The absorbing liquid S2 and air constitute a gas-liquid mixed fluid in the ejection pipe 42. The gas-liquid mixed fluid is ejected into the tank body 41 by the ejection pipe 42 and rises while turning in the tank body 41. The sulfide absorbed in the absorbing liquid S2 is oxidized by oxygen in the gas-liquid mixed fluid. As a result, the ability of the absorbing liquid S2 to absorb the sulfide of the coke oven gas G1 is restored.

  The gas-liquid mixed fluid that has reached the upper portion of the tank body 41 flows out of the tank body 41 and flows into the deaeration tank 50. The gas-liquid mixed fluid flowing into the deaeration tank 50 is separated into the absorbing liquid S2 and air, the air is discharged from the liquid surface, and the absorbing liquid S2 is sent out from the absorbing liquid delivery port 54.

  The absorbing liquid S2 delivered from the absorbing liquid delivery port 54 is pumped to the absorbent receiving port 23 side by the pump P2. A part of the absorption liquid S2 toward the absorption liquid receiving port 23 is discharged through the drainage pipe L10. The remaining absorption liquid S2 is diluted with water or the like replenished through the replenishment pipe L11, and then received again into the desulfurization tower 20 from the absorption liquid inlet 23. In this way, at least a part of the absorbing liquid S2 is circulated and used through the liquid feeding lines L7 and L9.

  The amount of the absorbing liquid S2 discharged from the drainage pipe L10 is set so that, for example, the amount of sulfur in the absorbing liquid S2 entering the desulfurization tower 20 from the absorbing liquid inlet 23 is equal to or less than an allowable value. . The absorbing liquid S2 is diluted with water replenished from the replenishing line L11. However, since the replenished water absorbs ammonia in the coke oven gas G1, the content of ammonia in the absorbing liquid S2 becomes an appropriate value. Kept.

  As described above, the desulfurization apparatus 1 includes the desulfurization tower 20 that causes the coke oven gas G1 and the absorbing liquid S2 to countercurrent contact with each other, thereby absorbing the sulfide in the coke oven gas G1 into the absorbing liquid S2, and the desulfurization. A regenerator 30 is provided which supplies a gas containing oxygen to the absorbing liquid S2 discharged from the tower 20 to oxidize sulfides and circulates at least a part of the absorbing liquid S2 to the desulfurization tower 20. The desulfurization tower 20 has a plurality of stages of absorption layers 26. The plurality of stages of absorption layers 26 are provided so as to be vertically spaced apart from each other, each having a thickness of 200 to 1500 mm, temporarily holding the absorption liquid S2 and guiding it from top to bottom, and coke. The furnace gas G1 is passed from the bottom to the top.

  If the thickness of the absorption layer 26 is too small, the contact efficiency between the coke oven gas G1 and the absorption liquid S2 in the absorption layer 26 becomes insufficient. On the other hand, if the thickness of the absorption layer 26 is too large, the air permeability of the absorption layer 26 decreases due to accumulation of solid sulfur generated by the oxidation reaction in the regeneration tower, and the contact efficiency between the coke oven gas G1 and the absorption liquid S2 decreases. To do. If the thickness of the absorption layer 26 is 200 mm or more, sufficient contact efficiency between the coke oven gas G1 and the absorption liquid S2 can be obtained. When the thickness of the absorption layer 26 is 1500 mm or more, the cleaning effect of solid sulfur and the like due to the falling / collision energy of the absorption liquid is reduced, solid sulfur and the like accumulate in the absorption layer 26 and the flow path is blocked, and desulfurization is performed. Tower maintenance may be difficult. On the other hand, if the thickness of the absorbing layer 26 is 1500 mm or less, the generated solid sulfur is swept away by the absorbing liquid S2, so that the contact efficiency of the coke oven gas G1 and the absorbing liquid S2 is reduced due to the accumulation of solid sulfur. Is suppressed. For this reason, sufficient contact efficiency of coke oven gas G1 and absorption liquid S2 is maintained for a long term because the thickness of absorption layer 26 is 200-1500 mm.

  The regeneration tower 30 has a mixing tank 40. The mixing tank 40 receives the absorbing liquid S2 from the desulfurization tower 20 and receives a gas containing oxygen to form a gas-liquid mixed fluid, and raises the gas-liquid mixed fluid while swirling. Thereby, the fluidity of the whole gas-liquid mixed fluid accommodated in the mixing tank 40 is obtained, whereby the stirring and mixing of the gas containing oxygen and the absorbing liquid S2 becomes quick and uniform. Therefore, the ability of the absorbing liquid S2 to absorb sulfide (hereinafter referred to as “absorbing ability of the absorbing liquid”) is sufficiently recovered.

  Thus, the sufficient contact efficiency of the coke oven gas G1 and the absorption liquid S2 is maintained in the desulfurization tower 20 for a long time, and the absorption capacity of the absorption liquid S2 is sufficiently recovered in the regeneration tower 30, so that high desulfurization is achieved. Capability can be maintained over the long term. Therefore, the desulfurization apparatus 1 is excellent in desulfurization capability.

  The desulfurization apparatus 1 further includes a precooling tower 10. The precooling tower 10 cools the coke oven gas G1 by bringing the coke oven gas G1 into countercurrent contact with the coolant S1 containing tar at a content rate of 1 to 6% in the preceding stage of the desulfurization tower 20.

  The absorption capacity of the absorption liquid S2 tends to improve as the temperature of the coke oven gas G1 decreases. For this reason, by cooling the coke oven gas G1 in the previous stage of the desulfurization tower 20, the desulfurization capacity of the coke oven gas G1 is improved. Since the cooling liquid S1 of the precooling tower 10 contains tar, even if naphthalene in the coke oven gas G1 is precipitated by cooling, the precipitated naphthalene is absorbed by the tar and is washed away together with the cooling liquid S1. For this reason, accumulation of naphthalene in the precooling tower 10 is suppressed, and the ability of the precooling tower 10 to cool the coke oven gas G1 is maintained for a long time. Therefore, the desulfurization capacity can be improved by cooling the coke oven gas G1, and the improvement effect can be maintained for a long time. In addition, it is not essential that the cooling liquid S1 contains tar, and it is not essential that the precooling tower 10 is provided.

  The mixing tank 40 has a tank body 41 and an injection pipe 42. The tank body 41 stores the gas-liquid mixed fluid. The injection pipe 42 is provided in the lower part in the tank main body 41, receives the gas containing the absorbing liquid S2 and oxygen, and injects the gas-liquid mixed fluid into the tank main body 41. The ejection pipe 42 has a plurality of pipe bodies 42a to 42c arranged in the jet direction of the gas-liquid mixed fluid, and is configured to suck the surrounding fluid between the pipe bodies 42a to 42c by an ejector effect. The gas-liquid mixed fluid is disposed so as to form a swirling flow in the tank body 41.

  For this reason, since the swirl flow is formed in the tank body 41 by the jet flow of the gas-liquid mixed fluid, the gas-liquid mixed fluid rises while swirling in the tank body 41. Thereby, since the fluidity of the gas-liquid mixed fluid is obtained in the absorbing liquid S2, the stirring and mixing of the gas containing oxygen and the absorbing liquid becomes quick and uniform, and the oxidation reaction proceeds efficiently. A part of the gas-liquid mixed fluid injected into the tank body 41 is again sucked into the injection pipe 42 by the ejector effect, so that the gas-liquid mixed fluid rises while swirling through the tank body 41. The gas containing oxygen is sufficiently mixed in the gas-liquid mixed fluid. Therefore, the absorption capacity of the absorption liquid S2 can be recovered efficiently and reliably. Note that swirling the gas-liquid mixed fluid using the jet flow of the gas-liquid mixed fluid also contributes to simplification of the structure of the mixing tank 40.

  The tank body 41 has a cylindrical side wall 41a, and the height of the side wall 41a is not more than twice the inner diameter of the side wall 41a and not less than 1 m.

  If the depth of the gas-liquid mixed fluid accommodated in the tank body 41 is too small, the oxidation rate of the sulfide in the absorbing liquid S2 tends to be significantly reduced. If the height of the side wall 41a is increased, the depth of the gas-liquid mixed fluid is also increased, so that the oxidation rate of the sulfide in the absorbing liquid S2 is improved, but the energy consumption for flowing the absorbing liquid S2 (for example, the pump P2) Energy consumption) also increases. Further, if the height of the side wall 41a is increased and the depth of the gas-liquid mixed fluid is increased too much, the improvement of the oxidation rate is slowed down, which is uneconomical.

  FIG. 7 is a graph showing the relationship between the depth of the gas-liquid mixed fluid housed in the tank body 41 having an inner diameter of the side wall 41a of 2 m and the oxygen utilization rate. The oxygen utilization rate is a ratio of oxygen absorbed in the absorbing liquid S2 due to oxidation of sulfides among oxygen introduced into the injection pipe 42. A high oxygen utilization rate means a high oxidation rate of sulfide. As FIG. 7 shows, when the depth of the gas-liquid mixed fluid accommodated in the tank main body 41 will be less than 1 m, there exists a tendency for the oxidation rate of the sulfide in absorption liquid S2 to fall remarkably. When the depth of the gas-liquid mixed fluid accommodated in the tank body 41 is increased, the oxidation rate of the oxide in the absorbing liquid S2 is improved. However, when the depth of the gas-liquid mixed fluid exceeds 4 m, the oxidation rate is improved. Tends to slow down. From this result, the following matters are estimated. That is, if the height of the side wall 41a is 1 m or more, the oxidation rate of the sulfide in the absorbing liquid can be ensured. If the height of the side wall 41a is less than or equal to twice the inner diameter of the side wall 41a, an oxidation ability commensurate with energy consumption can be obtained. Therefore, if the height of the side wall 41a is not more than twice the inner diameter of the side wall 41a and is 1 m or more, the oxidation ability can be secured with high energy efficiency.

  The regeneration tower 30 further includes a deaeration tank 50. The deaeration tank 50 is provided so as to surround the mixing tank 40, and is configured to receive the gas-liquid mixed fluid discharged from the mixing tank 40, separate it into the absorbing liquid S2 and the gas, and discharge it. For this reason, since gas is removed from the absorption liquid S2, generation | occurrence | production of the cavitation in the pump P2 which pumps the absorption liquid S2 is suppressed. Thereby, the absorption liquid S2 can be circulated stably between the desulfurization tower 20 and the regeneration tower 30. Therefore, the desulfurization capacity can be maintained more reliably.

  The regeneration tower 30 may be anything as long as it raises the absorbing liquid S2 while swirling, so the deaeration tank 50 is not essential. It is not essential that the height of the side wall 41a is not more than twice the inner diameter of the side wall 41a and not less than 1 m. It is not essential that the injection tube 42 is configured to suck the surrounding fluid by the ejector effect. It is not essential for the injection pipe 42 to be arranged so as to form a swirling flow by the injection of the absorbing liquid S2, and another configuration for generating the swirling flow may be provided. Other configurations for generating the swirling flow include a configuration in which the communication pipe 43 is inclined with respect to the side wall 41a in a plan view, and the absorbent S2 is introduced along the tangential direction, and spirals from the bottom to the top of the mixing tank 40. The structure which arrange | positioned a plate-shaped board, or the structure provided with the rotary blade for swirl | flow flow generation | occurrence | production are mentioned.

  Although the embodiment has been described above, the present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 ... Desulfurization apparatus, 10 ... Pre-cooling tower, 20 ... Desulfurization tower, 26 ... Absorption layer, 30 ... Regeneration tower, 40 ... Mixing tank, 41 ... Tank main body, 41a ... Side wall, 42 ... Injection pipe, 42a, 42b, 42c ... Tube, 50 ... deaeration tank, G1 ... coke oven gas, S1 ... coolant, S2 ... absorbing liquid.

Claims (5)

A desulfurization tower that absorbs the sulfide in the coke oven gas into the absorbent by bringing the coke oven gas and the absorbent into countercurrent contact;
A regenerative tower for supplying a gas containing oxygen to the absorption liquid discharged from the desulfurization tower to oxidize the sulfide and circulating at least a part of the absorption liquid to the desulfurization tower,
The desulfurization tower is
They are provided so as to be vertically spaced apart from each other, each having a thickness of 200 to 1500 mm, temporarily holding the absorbing liquid and guiding it from top to bottom, and the coke oven gas from bottom to top Has multiple layers of absorbent layers to pass through,
The regeneration tower is
A desulfurization apparatus comprising a mixing tank that receives the absorption liquid from the desulfurization tower, receives a gas containing oxygen, constitutes a gas-liquid mixed fluid, and raises the gas-liquid mixed fluid while swirling.   The pre-cooling tower which cools the coke oven gas by making the coke oven gas and the cooling fluid containing tar with the content rate of 1 to 6% countercurrent contact in the front part of the desulfurization tower is provided. The desulfurization apparatus according to 1. The mixing tank is
A tank body for containing the gas-liquid mixed fluid;
An injection pipe that is provided at a lower portion in the tank body and receives the gas containing the absorbing liquid and the oxygen and injects the gas-liquid mixed fluid into the tank body;
The jet pipe has a plurality of pipes arranged in the jet direction of the gas-liquid mixed fluid, and is configured to suck a surrounding fluid between the pipe bodies by an ejector effect. The desulfurization apparatus of Claim 1 or 2 arrange | positioned so that a swirling flow may be formed in the said tank main body by injection of a mixed fluid.   The desulfurization apparatus according to claim 3, wherein the tank body has a cylindrical side wall, and the height of the side wall is not more than twice the inner diameter of the side wall and not less than 1 m. The regeneration tower is
A deaeration tank is provided so as to surround the mixing tank, and is configured to receive the gas-liquid mixed fluid discharged from the mixing tank and separate and discharge the mixed liquid into a gas and an absorption liquid. Item 5. The desulfurization apparatus according to any one of Items 1 to 4.

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