CN108096997B - A kind of absorption liquid and application for wet dust removal process in high temperature plasma cracking coal to acetylene process - Google Patents

Abstract

The invention discloses an absorption liquid applied in the wet dust removal process in the high-temperature plasma cracking coal-to-acetylene process. and one or two of polyoxyethylene sorbitan fatty acid esters, the defoaming and foam suppressing agent is polydimethylsiloxane; the emulsifier accounts for 0.1-3 wt % of the total mass of the absorbing liquid; the defoaming and foam suppressing agent is It accounts for 0.1-2wt% of the total mass of the absorbing liquid. The invention improves the efficiency of dust removal and tar removal, and at the same time reduces the dissolution loss of acetylene and improves the economy and reliability of the whole process.

Description

A kind of wet dust removal process for high temperature plasma cracking coal to acetylene process Absorbent solution and application

technical field

The invention relates to a wet dedusting process in a high-temperature plasma cracking coal-to-acetylene process, in particular to an absorbing liquid in the wet dedusting process.

Background technique

my country is a country rich in coal and low in oil, and its dependence on foreign oil has exceeded 60%, which has seriously threatened my country's energy security. Therefore, vigorously developing coal chemical industry and utilizing clean transformation and high-value transformation of coal resources to generate basic chemical raw materials has important practical significance and far-reaching strategic significance. The existing calcium carbide method acetylene industry needs to consume a lot of electric energy and high-quality blue carbon, and discharge a lot of waste gas and dust, which seriously restricts its sustainable development. Plasma pyrolysis coal-to-acetylene technology is considered to be a promising green production technology for acetylene, which is in line with my country's energy status and is expected to replace calcium carbide as the mainstream way to produce acetylene in my country.

In the plasma cracking coal-to-acetylene process, the pyrolysis products produced after the coal powder carried by hydrogen passes through the high-temperature plasma torch are mainly hydrocarbons such as hydrogen and acetylene, and carry a large amount of incompletely reacted fine coal powder and coal. A mixture of a large amount of tar and other viscous substances generated by the cracking reaction, and in order to reduce the decomposition of acetylene, the cracked gas is quenched at a high speed in milliseconds after it comes out of the reactor. The quenching water absorbs heat energy and converts it into a large amount of water vapor. After passing through the quenching unit, all the water vapor will be taken away. It can be seen that the comprehensive properties of pyrolysis products are complex mixtures of extremely flammable and explosive, high dust content, tiny solid particles, very high humidity, and a large amount of coal tar and other adhesive components. Considering the subsequent separation process of acetylene and hydrogen, which requires safe and reliable removal of fine particles and tar from the cracked gas, wet dedusting process will be a relatively better choice, but at the same time the product acetylene will face the loss of dissolving in water. question. Therefore, how to develop a suitable absorbing liquid to improve the efficiency of dust removal and tar removal while reducing the dissolution loss of acetylene is of great significance for improving the economy and reliability of the entire process.

SUMMARY OF THE INVENTION

The invention provides an absorbing liquid applied in the wet dust removal process in the high temperature plasma cracking coal to acetylene process, which can improve the efficiency of dust removal and tar removal while reducing the dissolution loss of acetylene to improve the economy and reliability of the whole process.

An absorption liquid used in the wet dust removal process in the high-temperature plasma cracking coal-to-acetylene process is composed of an emulsifier and a defoaming and antifoaming agent dispersed in water. One or two kinds of sorbitan fatty acid esters, the defoaming and foam suppressing agent is polydimethylsiloxane; the emulsifier accounts for 0.1-3 wt% of the total mass of the absorption liquid; The mass ratio of the total liquid mass is 0.1-2 wt%.

The choice of the emulsifier in the present invention is to consider reducing the dissolution of acetylene while improving the emulsification effect, and the choice is a non-ionic surfactant, which has a stronger emulsification effect.

Preferably, the emulsifier accounts for 0.5-1.5wt% of the total mass of the absorption liquid; the defoaming and foam inhibitor accounts for 0.5-1.5wt% of the total mass of the absorption liquid; further preferably, the emulsifier accounts for the total mass of the absorption liquid ratio of 0.8 to 1.2 wt%; the mass ratio of defoaming and antifoaming agent to the total mass of the absorbing liquid is

0.8-1.2wt%; most preferably, the emulsifier accounts for 1wt% of the total mass of the absorption liquid; the defoaming and foam inhibitor accounts for 1wt% of the total mass of the absorption liquid.

Preferably, the emulsifier is compounded by sorbitan fatty acid ester and polyoxyethylene sorbitan fatty acid ester, and the HLB value of the emulsifier is 3-10. Further preferably, the HLB value of the emulsifier is 7.5-9.5; further preferably, the HLB value of the emulsifier is 9-9.5; most preferably, the HLB value of the emulsifier is 9.5.

Preferably, the sorbitol fatty acid ester is one or more of span80, span85 and span20.

Preferably, the polyoxyethylene sorbitan fatty acid ester is tween60.

Preferably, the viscosity of the polydimethylsiloxane is 300-1000 mPa·s; more preferably, the viscosity is 400-600 mPa·s; most preferably, the viscosity is 500 mPa·s.

Most preferably, the emulsifier is a compound of span20 and tween60, HLB=9.5, and the emulsifier accounts for 1% of the total mass of the absorbing liquid; the defoaming and foam suppressing agent is polydimethylsiloxane, with a viscosity of 500 mPa·s , accounting for 1% of the total mass of the absorption liquid.

The invention also provides a wet dust removal method for the flue gas produced by the high temperature plasma cracking coal to acetylene process, comprising the following steps:

(1) The flue gas generated by the high temperature plasma cracking coal to acetylene process is quenched and sent to the cyclone for pre-dust removal, and the large particle dust larger than 5 μm is basically removed;

(2) The flue gas after pre-dusting is sent to the jet bubbling tower, and it is accelerated into the absorption liquid in the tower through the injection pipe, and a large number of fine bubbles are blown up in the absorption liquid, so that the flue gas and the absorption liquid are fully contacted, and the coal is removed. Tar and dust are cooled to below 100°C; the absorption liquid is the absorption liquid of the present invention;

(3) Then it is sent to a wet electrostatic precipitator for fine dust removal, so that the dust content in the flue gas is less than or equal to 1mg/Nm ³ , and the flue gas after fine dust removal enters the subsequent gas separation section;

(4) The sewage generated in the steps (2) and (3) is sent to the sewage treatment tank for treatment, and then the reclaimed water is reused for the jet bubble tower and the wet electrostatic precipitator.

Preferably, the temperature in the jet bubbling tower is 30-40° C., and the gas flow rate is 150-250 ml/min. Further preferably, the temperature in the jet bubble column is 35°C, and the gas flow rate is 200ml/min.

The absorption liquid of the present invention has the following beneficial effects when it is used for processing the flue gas produced by the high-temperature plasma cracking coal-to-acetylene process through the compounding of the specific emulsifier component and the defoaming and anti-foaming agent:

(1) The raw materials of the absorbing liquid are widely sourced, the price is low, the preparation is simple, and there is no corrosive effect on the equipment.

(2) The absorption liquid has a good tar removal effect, the absorption amount is more than 200% higher than that of water, and the time for the complete disappearance of bubbles is reduced by 99%, which can significantly improve the absorption of tar.

(3) The dissolution rate of acetylene in the absorption liquid is about 90% of that in water, which reduces the loss of acetylene dissolution, improves economic benefits, and can significantly reduce the absorption of acetylene.

Detailed ways

The present invention will be further described below in conjunction with examples. It should be understood that the following examples are only used to illustrate the present invention but not to limit the scope of the present invention.

Example 1

Take 0.84g span80, 1.16g tween60, compound to obtain HLB=8.6 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 90%, the absorption of tar is increased by 265%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 2

Take 0.91g span85, 1.09g tween60, compound to obtain HLB=8.6 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with water absorption, the absorption of acetylene is reduced by 92%, the absorption of tar is increased by 260%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 3

Take 1.26g span80, 1.74g tween60, compound to obtain HLB=8.6 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 87%, the absorption of tar is increased by 275%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 4

Take 1.38g span80, 0.62g tween60, compound to obtain HLB=7.5 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 98%, the absorption of tar is increased by 252%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 5

Take 1.70g span20, 0.30g tween60, compound to obtain HLB=9.5 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, and fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 98%, the absorption of tar is increased by 273%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 6

Take 0.42g span80, 0.58g tween60, compound to obtain HLB=8.6 emulsifier, then add 2g polydimethylsiloxane, viscosity 500mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 93%, the absorption of tar is increased by 198%, and the time for complete disappearance of bubbles is reduced by 99%.

Example 7

Take 0.84g span80, 1.16g tween60, compound to obtain HLB=8.6 emulsifier, then add 1g polydimethylsiloxane, viscosity 500mPa·s, and fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 90%, the absorption of tar is increased by 263%, and the time for complete disappearance of bubbles is reduced by 96%.

Example 8

Take 0.84g span80, 1.16g tween60, compound to obtain HLB=8.6 emulsifier, then add 1g polydimethylsiloxane, viscosity 1000mPa·s, fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with water absorption, the absorption of acetylene is reduced by 90%, the absorption of tar is increased by 263%, and the time for complete disappearance of bubbles is reduced by 98%.

Example 9

Take 0.84g span80, 1.16g tween60, compound to obtain HLB=8.6 emulsifier, then add 1g polydimethylsiloxane, viscosity 300mPa·s, and fully mix with water to obtain 200g absorption liquid.

The obtained 200g liquid was placed in a small jet bubbling reactor for acetylene absorption and coal tar absorption tests. The temperature was 35°C, the gas flow was 200ml/min, the acetylene concentration was 7%, and the dust removal efficiency was 90%. Compared with the time of water absorption, the absorption of acetylene is reduced by 90%, the absorption of tar is increased by 264%, and the time for complete disappearance of bubbles is reduced by 95%.

The above is only a specific example of the implementation of the patent of the present invention, but the technical features of the patent of the present invention are not limited to this. within the scope of the patent.

Claims (6)

1. A wet dust removal method for flue gas generated in a process of preparing acetylene by cracking coal through high-temperature plasma is characterized by comprising the following steps:

(1) quenching flue gas generated in the process of preparing acetylene by cracking coal through high-temperature plasma, and then sending the flue gas to a cyclone dust collector for pre-dedusting, so that large particle dust larger than 5 microns is basically removed;

(2) sending the pre-dedusted flue gas into a jet bubble tower, accelerating the flue gas to be blown into absorption liquid in the tower through a jet pipe, and blowing a large amount of fine bubbles in the absorption liquid to ensure that the flue gas is in full contact with the absorption liquid, removing coal tar and dust, and cooling to below 100 ℃;

(3) then the flue gas is sent into a wet electric dust collector for fine dust removal, so that the dust content in the flue gas is less than or equal to 1mg/Nm³The flue gas after fine dust removal enters a subsequent gas separation section;

(4) sending the sewage generated in the steps (2) and (3) into a sewage treatment tank for treatment, and then reusing the reclaimed water in a jet bubble tower and a wet electric dust collector;

the absorption liquid is formed by dispersing an emulsifier and a defoaming and foam inhibiting agent in water and compounding, wherein the emulsifier is one or two of sorbitol fatty acid ester and polyoxyethylene sorbitan fatty acid ester, and the defoaming and foam inhibiting agent is polydimethylsiloxane; the emulsifier accounts for 0.1-3% of the total mass of the absorption liquid; the defoaming and foam inhibiting agent accounts for 0.1-2% of the total mass of the absorption liquid.

2. The method according to claim 1, wherein the emulsifier is prepared by compounding a sorbitol fatty acid ester and a polyoxyethylene sorbitan fatty acid ester, and the HLB value of the emulsifier is 3-10.

3. The process of claim 1 or 2, wherein the sorbitol fatty acid ester is one or more of span80, span85, and span 20.

4. The process according to claim 1 or 2, wherein the polyoxyethylene sorbitan fatty acid ester is tween 60.

5. The method according to claim 1, wherein the polydimethylsiloxane has a viscosity of 300 to 1000 mPa-s.

6. The method according to claim 1, wherein the temperature in the sparging bubble column is 30 to 40 ℃ and the gas flow rate is 150 to 250 ml/min.