CN106006569B - A kind of purifying technique of ammonia process wet type desulfurizing process byproducts sulphur cream - Google Patents

Abstract

A purification process of sulfur paste, a by-product of the ammonia wet desulfurization process, is to first send the concentrated ammonia water obtained by distilling ammonia from coking enterprises into the sulfur paste cleaning agent tank, and add a complexing agent to the sulfur paste cleaning agent tank, and mix evenly to prepare Obtain sulfur paste cleaning agent; then add sulfur paste and sulfur paste cleaning agent to the eluting device in proportion to elute, and then carry out solid-liquid separation, and the obtained filtrate is sent to the desulfurization reaction tank for the preparation of desulfurization liquid, and the obtained filter residue is sent to Enter the sulfur paste melting process; then send the filter residue into the sulfur melting kettle to melt sulfur, obtain liquid sulfur and form it into sulfur, the steam obtained from the upper part of the sulfur melting kettle is condensed and sent to the desulfurization reaction tank for the preparation of desulfurization liquid. This process effectively solves the problems of black color and low purity in the melting process of the existing sulfur paste, realizes the resource treatment and utilization of waste sulfur paste in coking enterprises, and improves the economic benefits of enterprises while protecting the environment.

Description

A purification process of sulfur paste, a by-product of ammonia wet desulfurization process

technical field

The invention relates to a purification process of sulfur paste, in particular to a purification process of sulfur paste produced in the desulfurization process of a coking enterprise using an ammonia wet oxidation process.

Background technique

In the process of desulfurization of coke oven gas by ammonia wet oxidation method, H ₂ S, HCN and NH ₃ in coke oven gas are absorbed by the desulfurization liquid, oxidized in the regeneration tower, and float in the regeneration tower in the form of sulfur foam. The upper part of the tower, and then flows into the foam tank for subsequent treatment.

Some enterprises process sulfur foam through the melting method. This method is to obtain sulfur after melting and filtering the sulfur paste in the range of 125 ° C to 158 ° C, so as to achieve the purpose of sulfur purification. However, the sulfur obtained by this method is black in color, low in purity and poor in marketability, and also has problems such as high energy consumption and large pollution. Therefore, most coking enterprises are more willing to centrifuge or filter sulfur foam to obtain sulfur paste with lower value.

In addition to the main component of sulfur, sulfur paste also contains a large amount of water and desulfurization by-products. Due to its low purity and poor quality, most coking enterprises sell the sulfur paste at a very low price, while some enterprises need to pay about 20-40 yuan/ton to the enterprises that recycle the sulfur paste, and some enterprises even sell the sulfur paste It is landfilled as waste. On the one hand, the above-mentioned treatment methods cause a waste of resources, and on the other hand, seriously threaten the safety and health of workers and surrounding people. Therefore, it is of great significance to realize the purification of sulfur paste in coking enterprises to improve the economic benefits of enterprises and reduce environmental pollution.

At present, some researchers have done relevant research on the purification of sulfur in sulfur paste. For example, Niu Yanxia leached sulfur paste with toluene, and obtained sulfur with a purity of more than 95% through a Soxhlet extraction device; the publication number is CN103264991A. A method of leaching sulfur paste by tetrachlorethylene was developed. Although this leaching method obtains high-purity sulfur, a large amount of organic solvents are introduced into the leaching process. In addition to safety problems such as explosion and high toxicity, there are also problems such as the price of the leaching agent is much higher than the price of sulfur, and serious losses during the leaching process. At present, no coking enterprise has used the above method to purify coking sulfur paste. Publication No. CN102976279A discloses a method of extracting ammonium thiocyanate in sulfur paste with a mixed organic solvent of methanol and acetone, and then washing and separating sulfur and ammonium thiosulfate to achieve the purpose of purifying the sulfur paste. But this method is aimed at the salt-rich sulfur paste, and fails to remove the insoluble substances in the sulfur paste.

Contents of the invention

The purpose of the present invention is to purify the sulfur in the sulfur paste. Aiming at the problems of blackening of sulfur and poor purity in the sulfur melting process of coking enterprises, and the introduction of a large amount of flammable and explosive organic solvents in the sulfur paste leaching process, a high cost problem has been developed. Purification process of sulfur paste, a by-product of ammonia wet desulfurization process, through selective complexation, solid-liquid separation and melting, etc., without introducing a large amount of flammable and explosive organic solvents, to solve the problem of melting sulfur paste to obtain sulfur To solve the problems of blackening and low purity, while realizing the resource treatment and utilization of sulfur paste, the effective components of the desulfurization catalyst in the sulfur paste are recovered.

The concrete technical scheme that the present invention takes is as follows.

A kind of purification process of ammonia wet desulfurization process by-product sulfur paste, said process is carried out according to the following steps:

(1) Preparation of sulfur paste cleaning agent: Send the concentrated ammonia water obtained by distilling ammonia from the coking enterprise into the sulfur paste cleaning agent tank, and at the same time add 10~50mg/L complexing agent into the sulfur paste cleaning agent tank, mix well and prepare Desulfur paste cleaning agent;

(2) Sulfur paste elution process: Add sulfur paste and the sulfur paste cleaning agent in the above steps to the elution device at a ratio of 1: 5 ~ 1: 100 (g/ml), and the elution temperature is 0 ~ 50 ℃, the elution time is 0.5~2h, and the solid-liquid separation is carried out after the elution is completed, and the separated filtrate is sent to the desulfurization reaction tank for the preparation of the desulfurization liquid, and the obtained filter residue is sent to the sulfur paste melting process;

(3) Sulfur paste melting process: Send the filter residue in the above steps into a sulfur melting kettle for sulfur melting. The sulfur melting temperature is 125°C~158°C, and the sulfur melting time is 0.5~5h. After cooling and forming in the sulfur forming tank, it is packaged and sold outside. The steam obtained from the upper part of the sulfur melting tank is condensed and sent to the desulfurization reaction tank for the preparation of desulfurization liquid.

Further technical scheme is as follows.

The complexing agent in the purification process is prepared from monoethanolamine, ethylenediamine and organic phosphate in a ratio of 1:1:1 to 1:3:7.

The extraction device of the purification process is a continuous countercurrent leaching device or a multi-stage leaching device.

The method of solid-liquid separation in the purification process is to use centrifugal separation or filtration separation equipment, and the temperature is 0-50° C., and the separation is 100-150 μm.

The outlet of the melting kettle in the purification process is equipped with a filter screen with a pore size of 50-100 μm.

Compared with the prior art, the purification process of the by-product sulfur cream of the ammonia wet desulfurization process provided by the present invention above uses the addition of monoethanolamine, ethylenediamine and organic phosphoric acid in the ammonia water that originally supplemented the alkali source of the desulfurization solution. The complexing agent such as salt is used as the sulfur paste eluting agent, which not only realizes the high-efficiency elution of impurities in the sulfur paste, but also realizes the recovery and reuse of effective components such as desulfurization catalysts, and reduces the consumption of catalysts in the desulfurization process. The eluted sulfur paste is purified by melting method, which effectively solves the problem of black color and low purity in the melting process of the existing sulfur paste, and obtains a sulfur product with high purity and good color, which realizes the waste of coking enterprises. The resource treatment and utilization of sulfur paste protects the environment and improves the economic benefits of the enterprise.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

In the figure: 1: foam tank; 2: foam pump; 3: main shell; 4: ammonia water pump; 5: filter device; 6: melting kettle; 7: sulfur forming tank; 8: desulfurization reaction tank; 9: feed port ;10: Liquid inlet; 11: Liquid outlet; 12: Spiral plate; 13: Material outlet; 14: Main shaft; 15: Sulfur cleaning agent tank.

detailed description

A further description is made to the technical solution provided by the present invention above.

Specific implementation mode 1

The sulfur paste used in this implementation case comes from a coking plant that adopts the HPF ammonia oxidation desulfurization process. The sulfur paste contains 38% water, 51% sulfur, and the rest is NH ₄ SCN, (NH ₄ ) ₂ S ₂ O _3. Impurities such as (NH ₄ ) ₂ SO ₄ total 11%; the ammonia water used comes from the ammonia distillation tower of the plant with a concentration of 11%; monoethanol ammonia, ethylenediamine and organic phosphate are all analytical reagents.

Dry and sieve the sulfur paste to obtain a sulfur paste sample with a particle size of <0.3mm and a moisture content of 1.76% (determination of moisture in industrial sulfur GB/T 2449.1-2014).

Preparation of sulfur paste cleaning solution: Add 35 mg of complexing agent prepared by monoethanolamine, ethylenediamine and organic phosphate at a ratio of 1:1:1 to 1L of ammonia water, and mix well to prepare sulfur paste cleaning agent.

Accurately weigh 25g of sulfur paste sample, wash with 100ml of sulfur paste detergent at room temperature, filter and observe the color change of the filtrate. Repeat the washing and filtering process four times, with a total of 400ml of sulfur paste detergent.

The filtrate was obtained by filtration, and dried at 80°C for 3 hours. After cooling and weighing, the drying process was repeated until the difference between two consecutive weighings did not exceed 0.002g, and the mass of the filter residue after drying was 23.5463g.

The filter residue is sent to a melting reactor with a filter device, and the filter residue is melted at 143° C. for 3 hours.

After the sulfur is obtained, the purity is measured according to the industrial sulfur GB/T 2449.1-2014, and the color is measured by a colorimeter. Measurement results: the purity is 98.6%, compared with the Lab value of the standard sample, the △L, △a, △b values are all less than 1.5.

Specific implementation mode 2

Accurately weigh 25g of sulfur paste sample, wash with 150ml of sulfur paste detergent at room temperature, filter and observe the color change of the filtrate. Repeat the washing and filtering process four times, with a total of 600ml of sulfur paste detergent.

The filtrate was obtained by filtration, and dried at 85°C for 3 hours. After cooling and weighing, the drying process was repeated until the difference between two consecutive weighings was no more than 0.002g, and the mass of the filter residue after drying was 24.0041g.

Send the filter residue into a melting reactor with a filter device, and carry out melting treatment on the filter residue at 150° C. for 3 hours.

After the sulfur is obtained, the purity is measured according to the industrial sulfur GB/T 2449.1-2014, and the color is measured by a colorimeter. Measurement results: the purity is 98.9%, compared with the Lab value of the standard sample, the △L, △a, △b values are all less than 1.5.

Claims (3)

1. a purification process of ammonia wet desulfurization process by-product sulfur paste, said process is carried out in the following steps: (1) Preparation of sulfur paste cleaning agent: send the concentrated ammonia water obtained by distilling ammonia in the coking enterprise into the sulfur paste cleaning agent tank (15), and add 10~50mg/L complexing ammonia into the sulfur paste cleaning agent tank (15) at the same time Agent, mixed evenly to make sulfur paste cleaning agent; (2) Sulfur paste elution process: add sulfur paste and the sulfur paste cleaning agent in the above step (1) to the elution device at a ratio of 1: 5 ~ 1: 100, and the elution temperature is 0 ~ 50 ° C. The elution time is 0.5~2h. After the elution is completed, the solid-liquid separation is carried out, and the separated filtrate is sent to the desulfurization reaction tank (8) for the preparation of the desulfurization liquid, and the obtained filter residue is sent to the sulfur paste melting process; (3) Sulfur paste melting process: send the filter residue in the above step (2) into the sulfur melting kettle for sulfur melting, the sulfur melting temperature is 125°C~158°C, the sulfur melting time is 0.5~5h, and the bottom of the sulfur melting kettle is obtained The liquid sulfur is cooled and formed in the sulfur forming tank (7) and then packaged for sale, and the steam obtained from the upper part of the sulfur melting tank is condensed and then sent to the desulfurization reaction tank (8) for the preparation of desulfurization liquid; The complexing agent is prepared by monoethanolamine, ethylenediamine and organic phosphate in a ratio of 1:1:1~1:3:7; In the above step (2), the ratio of the sulfur paste to the sulfur paste cleaning agent is g/ml. 2. The purification process as claimed in claim 1, wherein the extraction device is a continuous countercurrent leaching device or a multi-stage leaching device. 3. The purification process according to claim 1, the discharge port of the melting kettle has a filter screen with a pore size of 50-100 μm.