CN-121988133-A - Selective desulfurizing agent and application thereof

Abstract

The invention discloses a selective desulfurizing agent and application thereof, wherein the total mass of the selective desulfurizing agent is 100%, the selective desulfurizing agent comprises 5-35 wt% of s-triazine and derivatives thereof, 0.1-5 wt% of nitroguanidine and a water-soluble organic alkali compound, and the balance of water, wherein the content of the nitroguanidine is more than 0, and the content of the water-soluble organic alkali compound is more than 0. The desulfurizing agent can efficiently reduce the content of low-concentration sulfur in fuel gas, has higher selectivity under the condition of containing acid gas carbon dioxide, and reduces the content of hydrogen sulfide in the desulfurized gas to below 2mg/Nm 3 .

Inventors

• WANG SHUMAO
• WANG LIRONG
• WANG XIAOXIONG
• LI CHANGQING
• LUO QING
• WEI QINGHUA
• ZHAO YONG
• WEN SHANXIONG
• NIU JINLONG

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260508

Application Date

20241105

Claims (10)

1. 1.A selective desulfurization agent, characterized in that the selective desulfurization agent comprises, based on 100% of the total mass of the selective desulfurization agent: S-triazine and derivatives thereof, 5-35wt%; 0.1-5wt% of nitroguanidine and a water-soluble organic alkali compound; Water, the balance; wherein the content of nitroguanidine is more than 0, and the content of the water-soluble organic alkali compound is more than 0.
2. 2. The selective desulfurization agent according to claim 1, wherein the s-triazine and the derivative thereof comprise at least one of 1,3, 5-s-triazine and 1,3, 5-hydroxyalkyl-s-triazine, wherein the alkyl group in the 1,3, 5-hydroxyalkyl-s-triazine has 2 to 5 carbon atoms, and the mass ratio of nitroguanidine to the water-soluble organic base compound is 1:3 to 1:20.
3. 3. The selective desulfurization agent of claim 1, wherein the s-triazine and derivatives thereof comprise at least one of 1,3, 5-s-triazine, 1,3, 5-hydroxyethyl-s-triazine, and 1,3, 5-hydroxypropyl-s-triazine.
4. 4. The selective desulfurization agent of claim 1, wherein the water-soluble organic base compound is an aniline compound.
5. 5. The selective desulfurization agent according to claim 1, wherein the water-soluble organic base compound is at least one of phenylenediamine, o-ethylbenzylamine, dimethylamine, diethylamine, o-propylbenzylamine, phenylbutylamine.
6. 6. The selective desulfurization agent of claim 1, wherein the nitroguanidine has the structure:
7. 7. a method for removing hydrogen sulfide from fuel gas, characterized in that the fuel gas comprises carbon dioxide and hydrogen sulfide, and the fuel gas is contacted and reacted with the selective desulfurizing agent according to any one of claims 1-6 to remove hydrogen sulfide in the fuel gas.
8. 8. The method for removing hydrogen sulfide from fuel gas according to claim 7, wherein the content of hydrogen sulfide in the fuel gas is 20-100mg/Nm 3 and the volume content of carbon dioxide is 0.1-1.0%.
9. 9. The method for removing hydrogen sulfide from fuel gas according to claim 7, wherein the reaction pressure is 0.3 to 1.5MPa, and the reaction temperature is 30 to 70 ℃.
10. 10. The method for removing hydrogen sulfide from fuel gas according to claim 7, wherein the fuel gas is a gas obtained by preliminary desulfurization treatment of noncondensable gas discharged from catalytic cracking, catalytic hydrogenation or delayed coking.

Description

Selective desulfurizing agent and application thereof Technical Field The invention relates to the field of fuel gas desulfurization, in particular to a selective desulfurizing agent and application thereof. Background The content of sulfide in noncondensable gas discharged in the processes of catalytic cracking, catalytic hydrogenation, delayed coking and the like of oil refining enterprises is up to 3000-5000mg/Nm 3 (calculated by total sulfur, the same applies hereinafter), wherein the main component is hydrogen sulfide. The MDEA (N-methyldiethanolamine) is generally used as a hydrogen source or a fuel gas after removing sulfides therein. MDEA is a very good acid gas adsorbent, absorbs hydrogen sulfide in flue gas at low temperature, releases hydrogen sulfide under heating conditions (generally controlled in industry at 115-125 ℃), and high-concentration hydrogen sulfide gas is subjected to a Claus process to produce sulfur, so that the overall process can basically realize removal, enrichment and recovery of the hydrogen sulfide gas. The control index of the content of the gaseous hydrogen sulfide treated by the MDEA desulfurizing agent is not more than 20mg/Nm 3, and the content of the gaseous hydrogen sulfide at the outlet can fluctuate between 20-100mg/Nm 3 due to process fluctuation or the reduction of the foaming activity of the MDEA and the like, wherein the content of the carbon dioxide is about 0.1-0.3%. The desulfurized gas is typically used as a feed gas for a refinery furnace and is referred to as a fuel gas (also known as dry gas). In order to increase the heat utilization rate of the heating furnace and reduce the carbon emission, the sulfur content in the fuel gas needs to be reduced to below 2mg/Nm 3 so as to furthest reduce the concentration of sulfur oxides in the flue gas, reduce the possibility of generating sulfuric acid mist in the flue gas, reduce the temperature of discharged smoke and improve the heat efficiency. The outlet gas temperature of the MDEA device is 35-50 ℃, the fuel gas contains 0.1-0.3% of carbon dioxide gas, the acidity of the carbon dioxide and the hydrogen sulfide is close to that of the fuel gas, the sulfide cannot be removed by a common desulfurizing agent in the environment, and the hydrogen sulfide can be removed by a high-selectivity desulfurizing agent. For removing hydrogen sulfide with higher concentration, the common methods such as an alkaline method, an amine method and the like can be selected, so that the removal rate is very good, and when the content of hydrogen sulfide is reduced to below 20mg/Nm 3 and acid gas (CO 2) with similar properties is also contained in the hydrogen sulfide, the removal difficulty is greatly increased because the acidity of carbon dioxide and hydrogen sulfide is similar and the content of the hydrogen sulfide is far higher than that of the hydrogen sulfide. CN 115970443A discloses an absorption liquid for removing H 2 S from low sulfur-containing gas, the desulfurization absorption liquid comprising triazine, hindered amine, additive and water. Wherein the concentration of triazine is 5-10% (wt), the concentration of hindered amine is 5-10% (wt), the concentration of additive is 0.1-2% (wt), and the balance is water. The absorption liquid can effectively remove H 2 S in low-sulfur natural gas or oilfield associated gas. When the pressure of the raw material gas is 1-5 MPa and the temperature is 35-70 ℃, wherein H 2 S is 0.1-1%v, after purification, the content of H 2 S in the purified gas is less than or equal to 6mg/Nm 3, the index of the purified gas is reached, the absorption effect of the absorption liquid H 2 S is larger than that of the traditional absorption liquid, the consumption is less, and the absorption liquid has the scale inhibition performance. For gas-liquid absorption reaction, the pressure is an important process data, and the higher the pressure is, the stronger the dissolution capability of the gas in the liquid is, so that the gas absorption reaction is facilitated. The absorption liquid needs to realize the absorption of H 2 S under higher pressure, and the absorption selectivity needs to be improved. CN202310702249.6 discloses a porous polymer-based iron oxide desulfurizing agent and a preparation method thereof, which belong to the technical field of desulfurization, and the porous polymer is synthesized by design, and then iron oxide is loaded on the porous polymer to prepare the porous polymer-based iron oxide desulfurizing agent; the invention mainly utilizes the reaction of ferric oxide and hydrogen sulfide to realize the removal of hydrogen sulfide, belongs to the gas-solid reaction process in the aspect of hydrogen sulfide removal, can react with carbon dioxide to generate ferric carbonate at normal temperature, and has limitation in treating trace hydrogen sulfide gas containing a large amount of carbon dioxide. Therefore, there is still a need in the art for further research into desulfuri