CN113416585B

CN113416585B - Adsorption of H in coke oven gas2Method of S

Info

Publication number: CN113416585B
Application number: CN202110780585.3A
Authority: CN
Inventors: 樊振江; 史磊; 田二飞; 李龙博; 范瑞华; 杨海岳
Original assignee: Shenzhen Haoquan Environmental Protection Co ltd
Current assignee: Shenzhen Haoquan Environmental Protection Co ltd
Priority date: 2021-07-09
Filing date: 2021-07-09
Publication date: 2022-11-01
Anticipated expiration: 2041-07-09
Also published as: CN113416585A

Abstract

The application relates to adsorption of H in coke oven gas₂S method comprising flue gas pretreatment-fiber oxidation-adsorption of H₂The S-regenerated liquid is recycled, the common ion exchange fiber is converted into a form with an oxidizing group by using an oxidant, so that the common ion exchange fiber has both an ion exchange function and strong oxidizing property, and the oxidation, exchange and partial regeneration of the exchange fiber can be realized simultaneously without stopping work and production through the form of intermittently spraying a regenerant, so that the regenerated liquid has high-efficiency H adsorption₂The performance of S.

Description

Adsorption of H in coke oven gas2Method of S

Technical Field

The application relates to the technical field of coke oven gas purification, and relates to adsorption of H in coke oven gas₂S method, in particular to a method for adsorbing H in coke oven gas by ion exchange fiber₂S is partially regenerated at the same time.

Background

Coke oven gas, also known as coke oven gas, density at room temperature: 0.45 kg-0.47 kg/Nm³(average value), the English name is Cake Oven Gas (COG), because the combustible component is many, belong to high calorific value coal Gas, raw Gas or raw Gas. It is characterized by that several kinds of bituminous coals are used to prepare the coal for coking, and after high-temp. dry distillation in coking furnace, a combustible gas is produced at the same time of producing coke and tar productA by-product of the coke industry. The coke oven gas is a mixture, the yield and the composition of the coke oven gas are different due to different coking coal quality and coking process conditions, and each ton of dry coal can be used for producing the coke oven gas with the thickness of 300-350 m³(standard state).

The coke oven gas mainly comprises C, H, O and a small amount of N elements, has high calorific value, belongs to medium calorific value gas, has a calorific value of 17-19 MJ per standard cubic meter, and is suitable for being used as fuel of high-temperature industrial furnaces, urban gas and power generation. The coke oven gas has high hydrogen content, is used for synthesizing ammonia and then synthesizing urea in a chemical fertilizer after being separated, and can also be used for preparing clean energy, namely hydrogen; the coke oven gas contains more than 25% of other components such as methane and ethylene, the methane can be extracted to prepare natural gas, and the ethylene can be used as an organic synthetic raw material such as methanol. The coke oven gas composition is shown in table 1.

TABLE 1 Coke oven gas composition

Coke oven gas, which is a byproduct of the coking industry, usually contains a certain amount of hydrogen sulfide gas, and is widely used in the fields of methanol production, city gas supply, combustion power generation and the like. Therefore, the deep removal of hydrogen sulfide gas has a vital function and good market potential. Hydrogen sulfide not only causes a series of problems of catalyst poisoning, production cost increase, product quality reduction and the like, but also causes one of main substances of atmospheric pollution, greenhouse effect and ozone layer destruction, belonging to one of environmental pollutants which must be eliminated or controlled; while also having a significant negative impact on corrosion of industrial equipment.

H in coke oven gas₂S gas generates SO after being combusted₂，SO₂The discharge into the air can cause pollution to the environment. If H in the coke oven gas is reduced₂S gas is removed, and the coke oven gas can not generate SO after being combusted₂Is equal to the SO being solved from the source₂The pollution problem of (2).

Therefore, the improvement of the hydrogen sulfide gas treatment technology and the development and application of a new technology have important market development prospects.

The ion exchange material generally includes ion exchange resins, ion exchange fibers, and the like, and is a material having an ion exchange function. The anion exchange fibers have anion exchange groups and have high affinity and adsorption properties for anions. In the process of regenerating ion exchange material, because the adsorbed impurities are close to saturation state after the ion exchange fiber material is used for a period of time, the regeneration treatment is needed, and the currently common method is to elute and remove the ions and other impurities adsorbed by the ion exchange material by using chemical agents so as to restore the original composition and performance. However, during the regeneration process, shutdown is needed, the ion exchange fiber is eluted and regenerated separately, the construction period is long, and the ion exchange fiber needs to be used one by one. Meanwhile, in the whole hydrogen sulfide removal process, the whole process needs to be shut down, the ion exchange fibers are eluted and regenerated by chemical reagents independently, time and labor are consumed, or standby equipment is adopted for operation, the investment is large, the production safety is possibly influenced, the process progress is reduced, and therefore negative effects in the aspects of economic loss and environmental protection in different degrees are brought.

Disclosure of Invention

In order to solve the technical problems, the application provides a method for adsorbing H2S in coke oven gas by using ion exchange fibers and simultaneously partially regenerating the H2S, and the technology enables partial regeneration and ion exchange of ion exchange materials to be carried out simultaneously, so that the utilization rate of the ion exchange materials is improved, and the using amount of the fibers is greatly reduced.

The application provides a method for regenerating an ion exchange fiber material by intermittent spraying, which comprises the following specific steps: intermittently spraying oxidant solution, passing through the ion exchange fiber layer at a certain flow rate, and partially regenerating ion exchange fibers;

the time interval of the intermittent spraying is 4-12 hours, the spraying time is 30-40 min/time, and the liquid spraying amount of the oxidant spraying solution is 1/4-1/6 of the volume usage of the fiber material every time. The oxidant is K₂Cr₂O₇、NaClO、Ca(ClO)₂、NaClO₂、H₂O₂、KMnO₄ToOne or more of them.

The application relates to adsorption of H in coke oven gas₂The method of S comprises the following steps:

coke oven gas pretreatment-fiber oxidation-adsorption H₂And recycling the S-regenerated liquid.

(1) Pretreatment of coke oven gas: the treatment comprises the processes of dust removal and temperature reduction of the coke oven gas;

(2) Fiber oxidation: intermittently spraying an oxidant solution, wherein the oxidant spraying solution passes through the ion exchange fiber layer at a certain flow rate to enable the ion exchange fiber to become an oxidized ion exchange fiber;

(3) Adsorption of H₂S: h in coke oven gas₂S is oxidized by the ion exchange fiber to form sulfate ions, and the sulfate ions are adsorbed by the ion exchange fiber, so that the adsorption of H2S in the coke oven gas is realized.

The method comprises the following steps: h in coke oven gas₂S＜20mg/m³SO produced after combustion₂The content is less than 35mg/m³The low-concentration discharge can be achieved without treatment, and the ion exchange fiber of the invention is used for treating H in the coke oven gas₂The content of S is less than 15mg/m³，H₂The S adsorption efficiency reaches more than 99 percent.

(4) And (3) recycling the regenerated liquid: and recycling the regenerated waste liquid, namely recycling the leaching waste liquid and regenerating the leaching waste liquid.

In the step (1), the coke oven gas pretreatment comprises the processes of dust removal and temperature reduction of the coke oven gas. Generally, the discharge temperature of the coke oven gas is about 120-180 ℃, the adaptive temperature of the ion exchange is below 60 ℃, and before the coke oven gas enters the ion exchange material, the temperature of the coke oven gas is reduced to 40-90 ℃, preferably 50-70 ℃, so that the ion exchange fiber can reach the optimal use state during ion exchange, and the removal rate can be increased. Optionally, the pretreatment of coke oven gas also comprises dust removal treatment, and because a large amount of dust particles in the coke oven gas can block the gaps in the fiber layer and cover the anion exchange fibers, the working exchange capacity of the ion exchange fibers is reduced, and purification H in the subsequent process is easily caused₂The S effect decreases.

The coke oven gas can be cooled by a coke oven gas-water heat exchanger, the temperature of the coke oven gas is reduced, and the heated water after absorbing the heat of the coke oven gas is conveyed back to the boiler for use, so that the heat efficiency of the boiler can be greatly improved. The method can reduce environmental pollution and protect the environment, and can also generate certain economic benefit. The energy-saving and environment-friendly effects are achieved. The coke oven gas cooling system can also be adopted in the coke oven gas cooling process, and the effect of cooling is also achieved.

The anion exchange fiber has anion exchange groups, has high affinity and adsorption performance for anions, and is in a molecular state of H in coke oven gas₂S has no adsorption effect. Therefore, H in the coke oven gas must be removed₂S is dissolved in water and becomes the ion-state hydrosulfate ions which can be absorbed by the ion exchange material. However, H₂The solubility of S is small, the effect of complete removal cannot be achieved by water dissolution or alkali liquor absorption, and only the hydrogen sulfide ions can be further oxidized into high-valence sulfides according to the characteristics that the hydrogen sulfide ions are toxic, unstable and easy to be oxidized. According to H₂S has the characteristic of reducibility, can be oxidized into high-valence sulfuric acid when contacting with a strong oxidant, high-valence sulfate ions are very easy to dissolve in water to form sulfate ions, and the strong base anion exchange material has high affinity and adsorption performance for sulfate radicals and can adsorb the sulfate ions in a solution.

The ion exchange fiber is strong-base or weak-base anion exchange fiber, and the anion resin is preferably strong-base anion exchange fiber.

According to at least one embodiment, the anion exchange fibers are a blend containing one of quaternary amine functional groups, secondary amine functional groups, primary amine functional groups, or tertiary amine functional groups.

The anion exchange fiber can adopt CO₃Strong alkali type fiber, OH wool type weak alkali type fiber, OH cloth type weak alkali fiber, and OH strong alkali type fiber is preferable.

In the step (2), the fiber oxidation process is to use oxidant with a certain concentration to spray solution, pass through the fiber layer at a certain flow rate, and make the anion of the ion exchange fiber generate ion exchange reaction, so that the ion exchange fiber is in the form of oxidant, and the ion exchange fiber has ion exchange and oxidation effects at the same time.

The oxidant is K₂Cr₂O₇、NaClO、Ca(ClO)₂、NaClO₂、H₂O₂、KMnO₄One or more of (a).

Adding a small amount of alkali solution into the liquid oxidant solution, and adjusting the pH value of the system. NaClO has strong oxidizability under an acidic condition (PH 5-6), the oxidizability is quickly depleted, and the oxidation duration is short; although the oxidizing property is slightly weakened under the alkaline condition (pH 9-12), the oxidizing property can be maintained for a long time, so that in order to properly prolong the oxidizing time of NaClO and reduce unnecessary consumption, a proper amount of alkali liquor is required to adjust the pH of the solution.

RCl+NaOH→ROH+NaCl

The alkali can be NaOH, KOH, naHCO₃,Na₂CO₃And one or more of ammonia water.

In the oxidant spraying solution, the content of the oxidant is 0.5-6wt%, preferably 0.8-5wt% based on 100% of the solution; 1-6wt% of alkali liquor and the balance of water.

Compared with a gas oxidant, the liquid oxidant solution is preferably selected, the liquid oxidant with the appropriate concentration is prepared, the spraying mode is adopted, the oxidation and ion exchange efficiency can be improved, the spraying operation is simple, the cost is low, the operation condition is simple and easy to control, and the production cost is reduced.

In at least one embodiment of the present invention, the strong base anion exchange fibers have strong base anion exchange groups (-CH)₂N-(CH₃)₃Cl^-) The exchangeable ions on the exchange groups of the common strong base anion exchange fiber are chloride ions and have no oxidability. The structural formula is as follows:

when the oxidant spraying solution (taking NaClO as an example) of the invention passes through the ion exchange material layer at a certain flow rate, the ClO in the NaClO solution^-I.e. replacement of HCO on ion exchange materials^- ₃Part of the ion exchange material is transformed into RClO, the form of the ion exchange group is changed, the ion exchange material becomes an oxidant with the effect of a strong oxidant, and the ion exchange material is an ion exchanger with the function of ion exchange. ClO adsorbed on fibrous material^-Unstable and still have the effect of a strong oxidizing agent. The converted ion exchange fibers have thus become the oxidant form.

RHCO₃+NaClO→RClO+NaHCO₃

The structural formula of RClO is as follows:

in the step (3), the ion exchange fiber material adsorbs H in the coke oven gas₂The main mechanism of S is as follows:

after the ion exchange fiber is converted into the oxidant form, the coke oven gas enters the ion exchange layer, and hydrogen sulfide in the coke oven gas firstly performs neutralization reaction with liquid alkali liquor NaOH carried on the surface of the ion exchange material and in gaps to form Na easily soluble in water₂S, then Na₂The S is continuously subjected to liquid oxidation reaction with NaClO, and after oxidation, the S^2-Is oxidized to higher valence SO^2- ₄；

After hydrogen sulfide in the coke oven gas enters the ion exchange layer, the reaction is not completely finishedH of (A) to (B)₂S continues to perform neutralization reaction and oxidation reaction with ROH and RClO on the internal functional group of the ion exchange material respectively, H₂Part of S is neutralized and absorbed to form sodium sulfide, and part of S is oxidized by NaClO to form Na₂SO₄Then sulfate ions are adsorbed on the ion exchange material, thereby removing H₂And (5) the purpose of S. The ion exchange fiber after redox reaction is restored to chlorine type (RCl) and still has ion exchange capacity.

At the same time, CO in the coke oven gas₂And slightly water-soluble H₂The S gas and the alkali liquor (taking NaOH as an example) in the oxidant shower liquid are subjected to neutralization reaction, so that the hydrogen sulfide which is slightly soluble in water is firstly dissolved in the alkali liquor (sodium hydroxide) to form hydrogen sulfate radical ions.

The function of the lye in the present application has the following three aspects: neutralizing CO in coke oven gas₂And H₂S and other acidic gases; buffer the decomposition rate of liquid oxidants (such as NaClO), prolong the oxidation time; to absorb SO₄ ^2-And SO₃ ^2-The ion exchange material of (a) is regenerated.

The method utilizes the basic principle of ion exchange to change the form of exchange groups of ion exchange fiber materials, so that the ion exchange fibers become 'oxidants' with the effect of strong oxidants and also become 'ion exchangers' with the function of ion exchange, when coke oven gas passes through an ion exchange fiber layer, hydrogen sulfide is neutralized and oxidized into sodium sulfide and sodium sulfate, then sulfate radicals are adsorbed by the ion exchange fibers, and H is removed₂And (4) purpose of S.

Meanwhile, partial regeneration of the ion exchange material is realized simultaneously by intermittently spraying the liquid oxidant solution, the specific spraying interval time is 4-12 hours, and the solution spraying time is 30-40 min/time.

The liquid spraying amount of the oxidant spraying solution is 1/4-1/6 of the volume usage of the fiber each time.

As the ion exchange fiber runs for a long time, naClO contained in the pores of the ion exchange fiber and ClO adsorbed on the fiber exchange groups^-Decomposition occurs gradually, causing unnecessary loss, and the oxidizing agent may also decompose by itself. Therefore, in time, partial ion exchange fiber material is regenerated, unnecessary loss of strong oxidant is avoided, the intermittent spraying of the application can regenerate the fiber in time, the problems are well solved, and the turnover rate and the utilization rate of the ion exchange fiber are improved.

According to the actual working condition, if the coke oven gas is H₂The concentration of S is higher, and the ion exchange fiber material needs to be regenerated in time, so the spraying time interval can be properly reduced, for example, the ion exchange material is sprayed and regenerated for 4 to 8 hours. If H is contained in the coke oven gas₂The S concentration is low, and the spraying time interval can be properly prolonged, such as 9-12 hours for spraying and regenerating the fibers.

When discharging H₂When the concentration of S exceeds the standard, indicating that the ClO on the fiber material is over^-When depleted, the oxidizing power has been lost and regeneration is required.

The intermittent spraying mode of spraying the solution by controlling the oxidant can adjust the spraying time, the interval time and the frequency, and can realize the partial regeneration function of the fiber.

Taking NaClO + NaOH as an oxidant solution as an example, when the spray solution passes through the ion exchange material layer, part of fibers are changed into RClO type again, and can continue to oxidize H₂And (4) the function of S. The basic principle is as follows:

it is known to those skilled in the art that in the conventional ion exchange process, the ion exchange process is to remove some ions, and the regeneration process is to elute some ions adsorbed on the ion exchange material by using a regenerant, so that the exchange and regeneration are completely opposite processes, and cannot be performed simultaneously.

The liquid oxidant solution is intermittently sprayed, so that the regeneration and exchange of the fibers can be carried out simultaneously. Because the oxidant is also a regenerant at the same time, the H in the coke oven gas₂S toolHas strong oxidizing effect, and when the oxidizing agent and the coke oven gas simultaneously pass through the fiber material layer, the liquid oxidizing agent and H₂S is subjected to oxidation-reduction reaction.

Specifically, the regenerant (i.e., the oxidant) reacts with H in the coke oven gas₂Concentration of S (e.g. 200 mg/m)³) Compared with the prior art, the concentration difference is more than tens of thousands times, so that the H in the regenerant and the coke oven gas₂When S simultaneously enters the ion exchange layer, the ion exchange material firstly adsorbs oxidant such as ClO^-Forming RClO ion exchange material to realize partial regeneration of fiber, and the regenerated ion exchange material is used to replace H in coke oven gas₂S has both oxidation and ion exchange functions.

In addition, because the conventional ion exchange adsorption process has the defects that the ion exchange fibers are ineffective after long-term operation, the whole process needs to be stopped, the ion exchange fibers are independently replaced or regenerated, the operation period and the operation cost are influenced by the stop of the process, and the regeneration period generally needs 15 to 20 days.

The regeneration of the fiber part is realized by spraying the oxidant, and the oxidation performance and the ion exchange performance are simultaneously achieved, so that the ion exchange fiber regeneration method is a great breakthrough to the current ion exchange adsorption process, can realize the regeneration of the ion fiber part in one day, and has high ion exchange fiber turnover rate and utilization rate; not only can the construction period be saved and the production be carried out continuously, but also the operation cost can be greatly reduced, the investment and the occupied area of standby equipment are reduced, the regeneration process is simplified, the fiber utilization rate is improved, the fiber use amount is reduced, the conventional shutdown regeneration is broken through, the confusion that the equipment needs to be used one by one when the equipment is shut down and regenerated in continuous operation is avoided, and the one-time investment is saved.

Moreover, because the liquid oxidant may have the problem of self-decomposition, if the whole regeneration, the utilization rate/saturation amount of the ion exchange fiber is required to reach 80%, the time is too long, the ion exchange capacity is weakened, and the utilization rate of the ion fiber is low, so that the method can realize partial regeneration of the fiber in time in one day by an intermittent spraying mode, does not need to wait for the complete saturation of the fiber material, and improves the utilization rate and the turnover rate of the fiber material.

According to at least one embodiment, the partial regeneration of the fibers of the present application consumes only half of the oxidant as the entire regeneration of the fibers (conventional shutdown, regeneration process), greatly reducing operating costs.

The adsorption of H in the coke oven gas₂S process, can also be according to the service condition of the fiber, H₂And adjusting the interval period of spraying under the conditions of S concentration and the like, and performing spraying regeneration on the ion exchange fiber.

According to at least one embodiment, the prepared oxidant solution is fed into the water distribution system of the ion exchange device to regenerate and convert the ion exchange material. The oxidant spraying solution is sprayed once every 4 hours for 40 minutes, and the spraying amount is 1/3R of the volume of the fiber.

The recycling of the regenerated liquid in the step (4) means that after the oxidant drenching liquid passes through the ion exchange material layer, part of the fiber material is regenerated, and when the regenerated liquid is recycled for a plurality of times and is recycled to be incapable of being reused, the discharged regenerated waste liquid contains a large amount of sulfate and sulfite (Na)₂SO₄、Na₂SO₃) In order to save water and reduce the discharge of waste water, the discharged waste liquid is passed through an ROH type ion exchange column, and a large amount of Na is added₂SO₄、Na₂SO₃Adsorbing on ion exchange material, recovering all the treated alkaline solution, and using it to prepare oxidant spraying solution again.

2ROH+Na₂SO₄→R₂SO₄+2NaOH

2ROH+Na₂SO₃→R₂SO₃+2NaOH

In the process, if the ROH strong base type ion exchange column is saturated and needs to be regenerated, the ion exchange column can be regenerated;

when the ROH strong base type ion exchange column is saturated, naOH solution with a certain concentration and with a volume twice that of the ion exchange material is used for regeneration, the former time of regenerated waste liquid is discharged, and the latter time of regenerated waste liquid is reserved for recycling in the next regeneration.

R₂SO₄+2NaOH→2ROH+Na₂SO₄

R₂SO₃+2NaOH→2ROH+Na₂SO₃

The technical advantages of the application are as follows:

1. the method utilizes the ion exchange technology to purify the hydrogen sulfide gas in the coke oven gas for the first time, and solves the problem of flue gas desulfurization from the source.

2. The ion exchange material is converted into a form with an oxidation group by using a strong oxidant, so that the common ion exchange material has both an ion exchange function and strong oxidizing property:

when containing H₂When the coke oven gas of S passes through the ion exchange material layer, the oxidizing agent (NaClO for example) contained in the pores of the ion exchange material and the ClO adsorbed on the exchange groups of the ion exchange material^-Namely H in the coke oven gas₂S is subjected to oxidation-reduction reaction;

the ion exchange material after the redox reaction is recovered to be in a salt form (RCl) and still has the ion exchange capacity;

SO formed after oxidation₃ ^2-And SO₄ ^2-Quickly dissolved in water to become H₂SO₄And H₂SO₃；

Generation of H₂SO₄And H₂SO₃At the same time, the water is absorbed by ion exchange material recovered to salt form (RCl), thereby achieving the purpose of removing H₂And (4) purpose of S.

3. In the ion exchange operation process, equipment does not need to be shut down and the ion exchange material is converted and regenerated at the same time, the routine of shutdown regeneration is broken, the confusion that the equipment needs to be used one by one during continuous operation in shutdown regeneration is avoided, and the one-time investment is saved.

The application enables the regeneration and the exchange of the ion exchange fiber material to be carried out simultaneously, and is subversion and innovation of the conventional ion exchange technology. The basic principle is as follows:

(1) The regenerant is also an oxidant, and is H in coke oven gas₂S has strong oxidizing effect, and when the regenerant and the coke oven gas simultaneously pass through the ion exchange layer, the oxidant and H in the coke oven gas₂S is subjected to oxidation-reduction reaction, and H in coke oven gas is subjected to regeneration of ion exchange materials₂S undergoes redox reaction.

(2) Concentration of regenerant and H in coke oven gas₂Compared with S, the difference is more than tens of thousands times, so when the regenerant and H in the coke oven gas₂When S enters the ion exchange layer at the same time, the ion exchange material firstly adsorbs ClO^-The regenerated ion exchange material is used for removing H in coke oven gas₂S has both oxidation and ion exchange functions.

4. In the running process of the equipment, the partial ion exchange material is regenerated in time, so that the utilization rate of the ion exchange material is improved, and the using amount of the ion exchange material is greatly reduced.

(1) After the ion exchange material is regenerated, if the ion exchange material is operated for a long time, naClO contained in pores of the ion exchange material and ClO adsorbed on exchange groups of the ion exchange material^-And the decomposition can be gradually carried out, so that unnecessary loss is caused, and therefore, the partial ion exchange material is regenerated in time, and unnecessary loss of the strong oxidant is avoided.

(2) Experiments prove that: the consumption of the regenerant of the partial regeneration of the ion exchange material is only half of that of the whole regeneration of the ion exchange material, thereby greatly reducing the operation cost.

The beneficial effect of this application does:

1. the method utilizes the spraying oxidant solution to convert the common ion exchange fiber material into a form with an oxidizing group, so that the common ion exchange fiber has both an ion exchange function and strong oxidizing property.

2. In the operation process of the hydrogen sulfide adsorption process of the ion exchange fiber, the equipment does not need to stop and carry out fiber transformation and regeneration at the same time, the routine of stopping and regenerating is broken, the confusion that the equipment needs to be used one by one when in continuous operation is avoided, the one-time investment is saved, the partial regeneration of the fiber in one day is realized, and the utilization rate and the turnover efficiency of the ion exchange fiber are improved.

3. In the operation process of the equipment, partial sub-exchange fibers are regenerated in time, the utilization rate of the fibers is improved, the use amount of the fibers and the oxidant is greatly reduced, the experimental data of the application prove that the consumption of the regenerating agent of partial regeneration of the fibers is only half of that of the whole regeneration, the one-time investment is low, and the operation cost is greatly reduced.

4. This application sprays the form of oxidant solution through the intermittent type, can accomplish not stop work, do not stop production, satisfy ion exchange fibre oxidation, exchange, palingenetic integration simultaneously, under the saturated condition of fibre exchange, the intermittent type sprays oxidant solution and can realize fibrous partial regeneration to have oxidation performance and ion exchange performance concurrently simultaneously, have efficient H₂S adsorption performance.

5. The process is suitable for treating low-temperature flue gas, and low-temperature flue gas generated by the production process does not need to be heated (a large amount of heat energy is consumed), and can be directly fed into an ion exchange device to achieve low-concentration emission; the waste heat of high-temperature flue gas discharged by a production process can be recycled through the flue gas heat exchanger, and part of energy can be saved.

6. Application H₂The S removal efficiency is up to more than 99 percent, the coke oven gas purification effect is good, and the treated H₂S content less than 15mg/m³Post combustion SO₂The content is very small, the emission requirement can be met without treatment, and the problem of desulfurization is solved from the source; CO 2₂The adsorption effect is good, and the removed carbon dioxide accounts for 30-50% of the total content of the carbon dioxide in the raw gas.

7. This application is with regeneration liquid recycle, only contains sodium chloride, sodium sulfate, sodium sulfite, sodium sulfide, sodium hydrosulphate, sodium bicarbonate in the waste liquid, does not have the toxic substance, no secondary pollution, and the waste water volume is few moreover, satisfies the emission requirement.

8. By preparing the appropriate oxidant spray liquid, the application can reach H₂The S removal efficiency is up to more than 99 percent, partial regeneration of fiber materials can be realized by controlling intermittent spraying of an oxidant, and the ion exchange material can be used for a long timeThe fiber can be repeatedly used, and the use efficiency of the fiber is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the application and together with the description serve to explain the principles of the application.

FIG. 1 is a process flow diagram of example 1.

Wherein, the device comprises 101-an ion exchange hydrogen sulfide removal device, 102-an oxidant storage barrel, 103-an oxidant recovery barrel, 104-a fan, 105-a coke oven gas inlet and 106-an air outlet.

Detailed Description

The present application will be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the present application. It should be noted that, for the convenience of description, only the portions related to the present application are shown in the drawings.

The application adsorbs H in coke oven gas₂The S process flow is as follows:

after the hydrogen sulfide removal system is started to operate, the coke oven gas enters the inner bottom layer of the ion exchange hydrogen sulfide removal device from the lower end of the ion exchange device, the coke oven gas at the bottom continuously rises by the negative pressure generated by the induced draft fan and enters the ion exchange material layer after being completely leached, and H in the coke oven gas₂S and CO₂Firstly, the Na which is easy to dissolve in water is formed by neutralization reaction with liquid alkali liquor which is present on the surface of the ion exchange material and in the gap₂S、Na₂CO₃And NaHCO₃Then Na₂S is continuously oxidized with liquid oxidants on the surface of the ion exchange material and in the gap, and after oxidation, S^2-Is oxidized to higher valence SO₄ ^2-Na is gradually consumed to a low concentration when the liquid oxidizing agent present on the surface of the ion exchange material and in the gaps is gradually consumed₂S will be oxidized to SO₃ ^2-And stably present on the surface and in the interstices of the ion-exchange materialIn a liquid oxidizing agent; then unreacted H in the coke oven gas₂S continues to perform neutralization reaction and oxidation reaction with ion exchange groups, most of H₂S is oxidized on the ion exchange group to form SO₄ ^2-And SO₃ ^2-SO formed₄ ^2-And SO₃ ^2-Absorbed by ROH type ion exchange material, the alkali liquor can be recycled and used for preparing oxidant spraying solution. Fraction H₂S and OH on the ion exchange group^-Exchange takes place to form R₂And S. To this end, H in the coke oven gas₂S gas is basically removed completely.

The coke oven gas from which hydrogen sulfide gas is completely removed is discharged to a main coke oven gas pipeline through an exhaust port at the upper end by a draught fan, leaching waste liquid is discharged to an oxidant recycling barrel 103 through a pump 2, and oxidant is pumped into an ion exchange hydrogen sulfide removal device 101 through a pump 1 to be used as secondary leaching liquid.

The treatment effect is evaluated and detected by a third-party authoritative detection institution (Guangdong Zhiqing detection technology Co., ltd.), the hydrogen sulfide gas is detected according to an air and waste gas monitoring and analyzing method, the specific result is shown in table 2, the components of the leaching waste liquid are shown in table 3 in detail, and the leaching waste liquid can completely meet the emission requirement.

Example 1

Take the coke oven gas processing unit of No. 4 furnace in Shao-II power station as an example, 1080m³H in/H coke oven gas₂The S content is 163mg/m³：

1) Transformation: adopting OH strong base anion exchange fiber 8.34m³Transformation of the ion exchange material with 3% NaClO +5% NaOH (pH about 13) first before use; controlling the space flow rate by 1 time during transformation, wherein the dosage is 2 times of the volume of the ion exchange material;

2) And operation: starting the induced draft fan to normally operate (the induced draft fan is not stopped during operation to spray liquid);

3) And operation end point control: when treated H₂S gas leakage amount exceeds 15mg/m³(or H)₂S, the test paper begins to change color) and starts to drench liquid;

4) And liquid pouring: the oxidant is prepared for oxidation in the storage barrelDose 2.78m³Opening valves A and B, closing valves D, C and E, starting pump 1, controlling oxidant flow 4.17m³And h (0.5 time of space flow rate), closing the pump 1 and the valve B after running for 40min (the use amount of leaching liquid is one third of the volume of the fiber), opening the valve C, starting the pump 2 to fully pump the leaching waste liquid at the bottom of the main equipment to the oxidant recycling tank 103 and recycle the leaching waste liquid, and then closing the pump 2 and the valve C.

Recycling leaching waste liquid: collecting the leaching waste liquid, opening valves A and D again after 4 hours, starting pump 1 to continuously leach the liquid, and controlling the flow of the oxidant to be 4.17m³H (0.5 time space flow rate), and closing the pump 2 after running for 40 min; the oxidant can be recycled 5 times.

Discharge of leaching waste liquid: and (3) repeating the steps 1) and 2) until the waste liquid can not be reused, opening the valve E, closing the valve C, starting the pump 2 to discharge the waste liquid which can not be recycled in the main equipment, and then re-preparing the oxidant solution.

Example 2

Spraying the oxidizer solution composition 4% Ca (ClO)₂+4% NaOH, the other steps were the same as in example 1.

Example 3

The spraying oxidant solution comprises the following components: 2% of NaClO₂+1% NaOH, the other steps were the same as in example 1.

Example 4

Spraying the oxidizer solution to 1.8% The NaClO +4% NaHCO₃The other steps are the same as in example 1.

Example 5

Spraying the oxidant solution to 0.8%₄+6% NaOH, the other steps were the same as in example 1.

Example 6

The composition of the oxidant solution sprayed was 3%₂O₂+5% NaOH, the other steps were the same as in example 1.

Example 7

The spray oxidizer solution composition was 5.5% NaClO +3% NaOH, the other steps were the same as in example 1.

Comparative example 1

The common D201SC anion exchange resin is adopted, no oxidant is sprayed, and shutdown regeneration is required.

Comparative example 2

Spraying the oxidant solution consisted of 3% NaClO +5% NaOH, the regeneration process was regenerated with an overall shutdown, different from the intermittent spray regeneration of example 1.

TABLE 2 examples and comparative examples H₂Efficiency of S removal process

TABLE 3 composition of the elution waste and the detection method

Comparing the ion exchange material regeneration process of example 1 with that of comparative example 1, it can be seen that the ion exchange material of example 1 of the present application can realize the functions of hydrogen sulfide oxidation, exchange removal, and partial regeneration of the ion exchange material by spraying an oxidant solution, and does not need to be shut down and stop production, and the amount of the oxidant (i.e. partial regenerant) is less; comparative example 2 requires shutdown for the overall regeneration of the ion exchange material, which not only consumes the construction period, but also requires spare equipment, occupies a large area, and has high investment cost and operation cost.

By examining the dosage of the regenerant in the example 1 and the dosage of the regenerant in the comparative example 2, as can be seen from table 2, the dosage of the regenerant used in the overall regeneration of the shutdown ion exchange material in the comparative example 2 is large, and the consumption of the regenerant in unit time is too much under the condition of the same flue gas treatment amount; in the embodiment 1, the mode of intermittently spraying the regenerant without shutdown is adopted, and under the condition of realizing the same coke oven gas treatment capacity and standard reaching time, the dosage of the oxidant (namely partial regenerant) adopted in the embodiment 1 is only 1/3 times of the volume of the ion exchange material, so that the consumption of the regenerant in unit time is less, the cost can be saved by partially regenerating fibers, and the operating cost can be reduced.

The method for preparing the liquid oxidant with the appropriate concentration adopts a spraying mode, so that the oxidation and ion exchange efficiency can be improved, the spraying operation is simple, the cost is low, and the operation condition is simple and easy to control; and the intermittent spraying can realize the partial regeneration of the fiber, thereby saving the process of regenerating the fiber, simplifying the process and reducing the production cost.

Table 4 use of regenerants from example 1 and comparative example 2

Volume of R-ion exchange fiber material in Table 2

The method adopts the process of liquid oxidant + ion exchange, utilizes the basic principle of ion exchange, changes the form of the exchange group of the ion exchange fiber, enables the ion exchange fiber to become the oxidant with the effect of strong oxidant, and the ion exchange fiber has the ion exchange function as the ion exchanger, thereby achieving the effect of efficiently removing hydrogen sulfide. Moreover, the oxidant also has the effect of a regenerant, can partially regenerate the fibers in an intermittent spraying mode, simultaneously realizes transformation, simultaneously meets the integrated process of exchange fiber hydrogen sulfide oxidation, exchange and regeneration, breaks through the routine of shutdown regeneration of the fibers, reduces the using amount of the regenerant and saves one-time investment.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are provided merely for clarity of disclosure and are not intended to limit the scope of the invention. Other variations or modifications may occur to those skilled in the art based on the foregoing disclosure and are still within the scope of the present application.

Claims

1. Adsorption of H in coke oven gas₂The method of S is characterized by comprising the following steps:

pretreatment of coke oven gas: the treatment comprises the processes of dust removal and temperature reduction;

fiber oxidation: intermittently spraying an oxidant solution, wherein the oxidant solution passes through the ion exchange fiber layer at a certain flow rate to enable the ion exchange fiber to become an oxidation type ion exchange fiber;

adsorption of H₂S: h in coke oven gas₂S is oxidized, and the oxidation product is adsorbed by the ion exchange fiber at the same time to realize H₂S is removed;

and (3) recycling the regenerated liquid: after the oxidant solution is recycled, the regenerated waste liquid is recycled;

the coke oven gas pretreatment step is carried out by adopting a flue gas cooling system, and the temperature of the coke oven gas is reduced to 40-90 ℃;

the ion exchange fiber is strong-base anion exchange fiber, and the anion exchange fiber contains one of quaternary amine functional group, secondary amine functional group, primary amine functional group or tertiary amine functional group;

exchangeable ions on the exchange groups of the strong-base anion exchange fibers are chloride ions;

the oxidant is NaClO, and the content of the oxidant is 0.5-6wt% calculated by 100% of the oxidant solution;

the oxidant solution contains a certain amount of alkali solution, and the alkali in the alkali solution is selected from NaOH, KOH and NaHCO₃,Na₂CO₃One or more of ammonia; the alkaline solution content is 1-6wt% calculated by taking the oxidant solution as 100%.

2. The method according to claim 1, wherein the intermittent spraying is in particular carried out with an oxidizer solution spraying time interval of 4 to 12 hours; the spraying time is 30-40 min/time.

3. The method of claim 2, wherein the oxidant solution is sprayed in an amount of 1/4 to 1/6 of the fiber volume used per pass, and the fiber portion is regenerated by intermittent spraying.

4. The method of claim 1, wherein the oxidizer solution has a PH of 8 to 14 and is reused 4 to 8 times.

5. The method as claimed in claim 1, wherein sulfate and sulfite in the regenerated waste liquid are treated by a strong basic anion exchange column ROH, and the alkaline solution is completely recovered and used for preparing the oxidant solution again.

6. The method as claimed in claim 5, characterized in that after saturation of the strongly basic anion exchange column ROH, the column is regenerated with NaOH solution of a certain concentration and twice the volume of the exchange material, the former regenerated waste liquid is discharged, and the latter regenerated waste liquid is left for recycling in the next regeneration.

7. The method of claim 1, wherein the flue gas cooling system is a flue gas-water heat exchanger.

8. The method of claim 1, wherein the temperature reduction process in the coke oven gas pretreatment step is: the temperature of the coke oven gas is reduced to 50-70 ℃.