CN113832272B

CN113832272B - Improved method for hydrolytic desulfurization of blast furnace gas

Info

Publication number: CN113832272B
Application number: CN202111140159.XA
Authority: CN
Inventors: 杨鹏; 王巍; 杨皓; 宋尉源
Original assignee: Sichuan Tianren Energy Technology Co ltd
Current assignee: Sichuan Tianren Energy Technology Co ltd
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2022-09-27
Anticipated expiration: 2041-09-28
Also published as: CN113832272A

Abstract

An improved process for hydrolytic desulfurizing blast furnace gas includes such steps as heating for hydrogenating reduction by potassium oxide-sodium oxide carried by alumina-titanium oxide-iron oxide carrier, and hydrolytic desulfurizing reaction to generate hydrogen sulfide and Fe in carrier, which form Fe-O-S structure without obvious decrease in hydrolytic activity. Along with the continuous reaction process, the activity is obviously reduced due to the blocking of the pores by the elemental sulfur, and then the activation is carried out. Firstly, nitrogen is circularly heated and blown out, when the sulfur content is lower than 20ppm, the nitrogen is switched into hydrogen-containing gas, elemental sulfur and sulfur in a carrier structure are blown out in the form of hydrogen sulfide, and when the gas-phase hydrogen sulfide is lower than 1ppm, the activation is completed, and the performance of the catalyst is basically recovered.

Description

Improved method for hydrolytic desulfurization of blast furnace gas

Technical Field

The invention relates to the fields of chemical industry, energy conservation and environmental protection, and discloses an improved method of a blast furnace gas desulfurization process.

Background

The conventional desulfurizer is a mixture containing oxides such as iron, calcium, aluminum, silicon and the like, the desulfurizer belongs to non-hazardous chemicals, and the waste desulfurizer after removing hydrogen sulfide in gas becomes hazardous chemicals waste due to adhesion and gathering of elemental sulfur. The common iron oxide desulfurizer removes hydrogen sulfide to generate iron sulfide, and the regeneration of the iron sulfide mainly adopts oxygen or steam for heating to convert the deposited elemental sulfur and the sulfur of the iron sulfide into sulfur dioxide or hydrogen sulfide again.

The process of removing organic sulfur from blast furnace gas is mainly a hydrolysis process, and most of hydrolysis catalysts are alumina and titanium oxide carriers loaded with alkali metal oxides. The principle of hydrolysis desulfurization is that alkali metal active sites absorb water to react with organic sulfur to generate hydrogen sulfide and carbon dioxide, and then the hydrogen sulfide and the carbon dioxide are desorbed. The reasons for catalyst deactivation are as follows:

(1) a small amount of oxygen exists in blast furnace gas, and part of hydrogen sulfide can be oxidized into elemental sulfur; the elemental sulfur is converted into sulfur dioxide, and the sulfur dioxide and hydrogen sulfide generate elemental sulfur. The two reaction processes can cause the deposition of elemental sulfur, block the pore channels of the catalyst and adhere to the surface to cause the inactivation of the catalyst;

(2) the elemental sulfur deposited on the catalyst is continuously oxidized into sulfate, the active sites of the alkali metal loaded on the catalyst are damaged, and the activity of the catalytic reaction process is reduced.

The inactivation of the catalyst causes low desulfurization purification rate of blast furnace gas, non-ideal desulfurization effect, higher operation cost, incapability of realizing continuous, stable and efficient operation and incapability of being applied to a large-scale continuous operation desulfurization process. The deactivated catalyst is regenerated through roasting, water washing, soaking, drying and roasting, and the roasting is to eliminate deposited sulfur and eliminate metal soluble salt before re-soaking the active component. Regeneration of the catalyst is a complex series of operations requiring replacement of the catalyst in the process equipment, which is a significant challenge for continuous industrial production.

Disclosure of Invention

The invention relates to an improved method for hydrolytic desulfurization of blast furnace gas, which is characterized by comprising the following steps: the hydrolysis desulfurizer in the desulfurization process is an alumina-titanium oxide-ferric oxide carrier, and the surface loaded potassium oxide-sodium oxide is used as an active center. Firstly, heating a catalyst to 150-180 ℃, introducing hydrogen-containing gas for circulation, removing excessive oxygen from iron oxide to form a sub-oxidation structure, and cooling the sub-oxidation structure for organic sulfur conversion of blast furnace gas; the organic sulfur reacts with water to generate hydrogen sulfide and oxycarbide, most of the hydrogen sulfide is directly discharged along with blast furnace gas, trace hydrogen sulfide reacts with framework ferrous oxide to generate iron-sulfur oxide, the iron-sulfur oxide has the function of hydrogenolysis of the organic sulfur in cooperation with titanium oxide-aluminum oxide, and the generated iron-sulfur oxide does not influence the hydrolysis performance of sodium oxide-potassium oxide.

The process of converting organic sulfur is continuously carried out, partial hydrogen sulfide is oxidized into elemental sulfur to gradually block pore channels, the hydrolysis catalytic performance of the catalyst is gradually reduced, and then the catalyst is switched to enter an activation process: firstly, nitrogen circulation program is adopted to heat and purge the catalyst, the temperature is 150-200 ℃, the catalyst stays for 0.2-8 hours, elemental sulfur in a large number of pore channels in the catalyst is desorbed and carried out by circulating gas, the elemental sulfur is cooled and separated, and the gas is recycled; after the gas-phase elemental sulfur is reduced to 20ppm, the gas-phase elemental sulfur is switched to hydrogen or hydrogen-containing gas for circular heating, the temperature is 200-280 ℃, the gas stays for 0.2-8 hours, sulfur in an iron-sulfur-oxygen structure in the catalyst is reduced to hydrogen sulfide to overflow, elemental sulfur and vacancy on the surface of the catalyst generate iron-sulfur-oxygen, the hydrogen sulfide desorption is carried out by circulating gas, the hydrogen sulfide is separated, and the gas is recycled; the iron-oxygen structure is used as an elemental sulfur hydrogenation catalyst, which is beneficial to completely converting elemental sulfur on the surface of the catalyst into hydrogen sulfide; and stopping activation after the gas-phase hydrogen sulfide is reduced to 1ppm, and almost completely recovering the performance of the activated catalyst.

Detailed Description

Example 1: the desulfurization catalyst is an alumina-titanium oxide-ferric oxide carrier, and potassium oxide-sodium oxide loaded on the surface is taken as an active center. The catalyst is heated to 150 ℃, and the iron oxide is reduced by pure hydrogen or circulating gas containing hydrogen, and then cooled. The blast furnace gas enters an organic sulfur conversion reactor, the reaction gas carries out hydrogen sulfide and oxycarbide, trace hydrogen sulfide reacts with ferrous oxide in a framework to generate iron-sulfur oxide, the iron-sulfur oxide has a synergistic effect on organic sulfur generated by hydrogenolysis of titanium oxide-aluminum oxide, and the generated iron-sulfur oxide does not influence the hydrolysis performance of sodium oxide-potassium oxide; the conversion process is continuously carried out, partial hydrogen sulfide is oxidized into elemental sulfur to gradually block the pore channel, the hydrolysis catalysis performance is gradually reduced, and the switching catalyst enters an activated state. Firstly, heating a catalyst by adopting a nitrogen circulating program, heating to 180 ℃ and keeping for 2 hours, desorbing elemental sulfur in a catalyst pore channel, taking out the elemental sulfur by circulating gas, cooling the gas to separate the elemental sulfur, and heating the gas for circulating purging; after gas-phase elemental sulfur is reduced to 20ppm, hydrogen or hydrogen-containing gas is switched to be heated to 250 ℃ circularly and is kept for 2 hours, sulfur in an iron-sulfur-oxygen structure in the catalyst is reduced to hydrogen sulfide to overflow, elemental sulfur attached to the surface of the catalyst generates iron-sulfur-oxygen with vacancy, the sulfur hydrogenation desorption is carried out by circulating gas, the gas circulates after the hydrogen sulfide is separated, the iron-oxygen structure is used as an elemental sulfur hydrogenation catalyst, the elemental sulfur on the surface of the catalyst is converted into hydrogen sulfide, the activation of the gas-phase hydrogen sulfide is stopped after the gas-phase hydrogen sulfide is reduced to 1ppm, and the performance of the activated catalyst is recovered to 90%.

Example 2: the desulfurization catalyst is an alumina-titanium oxide-ferric oxide carrier, and potassium oxide-sodium oxide loaded on the surface of the desulfurization catalyst is an active center. The catalyst is heated to 180 ℃, and the iron oxide is reduced by pure hydrogen or circulating gas containing hydrogen, and then cooled. The blast furnace gas enters an organic sulfur conversion reactor, the reaction gas carries out hydrogen sulfide and oxycarbide, trace hydrogen sulfide reacts with ferrous oxide in a framework to generate iron-sulfur oxide, the iron-sulfur oxide has a synergistic effect on organic sulfur generated by hydrogenolysis of titanium oxide-aluminum oxide, and the generated iron-sulfur oxide does not influence the hydrolysis performance of sodium oxide-potassium oxide; the conversion process is continuously carried out, partial hydrogen sulfide is oxidized into elemental sulfur to gradually block the pore channel, the hydrolysis catalysis performance is gradually reduced, and the switching catalyst enters an activated state. Firstly, heating the catalyst by adopting a nitrogen circulating program, heating to 160 ℃, keeping for 4 hours, desorbing elemental sulfur in a catalyst pore channel, taking out the elemental sulfur by circulating gas, cooling the gas to separate the elemental sulfur, and heating the gas for circulating purging; after the gas-phase elemental sulfur is reduced to 20ppm, switching hydrogen or hydrogen-containing gas to circularly heat to 280 ℃ and keeping for 3 hours, reducing sulfur in an iron-sulfur-oxygen structure in the catalyst into hydrogen sulfide to overflow, generating iron-sulfur-oxygen with the elemental sulfur attached to the surface of the catalyst and lacking, carrying out sulfur hydrogenation desorption by circulating gas, separating the hydrogen sulfide, circulating the gas, using the iron-oxygen structure as an elemental sulfur hydrogenation catalyst, converting the elemental sulfur on the surface of the catalyst into hydrogen sulfide, stopping activation after the gas-phase hydrogen sulfide is reduced to 1ppm, and recovering the performance of the activated catalyst to 93%.

Example 3: the desulfurization catalyst is an alumina-titanium oxide-ferric oxide carrier, and potassium oxide-sodium oxide loaded on the surface of the desulfurization catalyst is an active center. The catalyst is heated to 200 ℃, and the iron oxide is reduced by pure hydrogen or circulating gas containing hydrogen, and then cooled. The blast furnace gas enters an organic sulfur conversion reactor, the reaction gas carries out hydrogen sulfide and oxycarbide, trace hydrogen sulfide reacts with ferrous oxide in a framework to generate iron-sulfur oxide, the iron-sulfur oxide has a synergistic effect on organic sulfur generated by hydrogenolysis of titanium oxide-aluminum oxide, and the generated iron-sulfur oxide does not influence the hydrolysis performance of sodium oxide-potassium oxide; the conversion process is continuously carried out, partial hydrogen sulfide is oxidized into elemental sulfur to gradually block the pore channel, the hydrolysis catalysis performance is gradually reduced, and the switching catalyst enters an activated state. Firstly, heating the catalyst by adopting a nitrogen circulating program, heating to 180 ℃ and keeping for 4 hours, carrying out elemental sulfur desorption in a catalyst pore channel out by circulating gas, cooling the gas to separate elemental sulfur, and heating the gas for circulating purging; after the gas-phase elemental sulfur is reduced to 20ppm, switching hydrogen or hydrogen-containing gas to circularly heat to 280 ℃ and keeping for 6 hours, reducing sulfur in an iron-sulfur-oxygen structure in the catalyst into hydrogen sulfide to overflow, generating iron-sulfur-oxygen with the elemental sulfur attached to the surface of the catalyst and lacking, carrying out sulfur hydrogenation desorption by circulating gas, separating the hydrogen sulfide, circulating the gas, using the iron-oxygen structure as an elemental sulfur hydrogenation catalyst, converting the elemental sulfur on the surface of the catalyst into hydrogen sulfide, stopping activation after the gas-phase hydrogen sulfide is reduced to 1ppm, and recovering the performance of the activated catalyst to 96%.

Claims

1. An improved method for blast furnace gas hydrolysis desulfurization is characterized in that a hydrolysis desulfurizer in the desulfurization process is an alumina-titanium oxide-ferric oxide carrier, and potassium oxide-sodium oxide loaded on the surface is taken as an active center; firstly, heating a catalyst to 150-180 ℃, removing redundant oxygen in an iron oxide structure by using hydrogen-containing circulating gas to form a sub-oxidation structure, and cooling the sub-oxidation structure for converting organic sulfur in blast furnace gas; organic sulfur reacts with water to generate hydrogen sulfide and oxycarbide in the hydrolysis desulfurization process, most of the hydrogen sulfide is directly discharged along with blast furnace gas, trace hydrogen sulfide reacts with framework ferrous oxide to generate iron-sulfur oxide, the iron-sulfur oxide has the function of hydrogenolysis of the organic sulfur in cooperation with titanium oxide-aluminum oxide, and the generated iron-sulfur oxide does not influence the hydrolysis performance of sodium oxide-potassium oxide; continuously carrying out the conversion process, oxidizing part of hydrogen sulfide into elemental sulfur to gradually block a pore channel, gradually reducing the hydrolysis catalytic performance, switching the catalyst to enter an activation state, firstly heating the catalyst by adopting a nitrogen circulation program to 150-200 ℃, staying for 0.2-8 hours, allowing elemental sulfur in the pore channel in the catalyst to be desorbed and carried out by circulating gas, cooling and separating the elemental sulfur, and recycling the gas; after the gas-phase elemental sulfur is reduced to 20ppm, switching hydrogen or hydrogen-containing gas to circularly heat to 200-280 ℃, staying for 0.2-8 hours, reducing sulfur in an iron-sulfur-oxygen structure in the catalyst into hydrogen sulfide to overflow, generating iron-sulfur-oxygen from elemental sulfur and vacancy on the surface of the catalyst, carrying out sulfur hydrogenation desorption by circulating gas, separating the hydrogen sulfide, circulating the gas, taking the iron-oxygen structure as an elemental sulfur hydrogenation catalyst, being beneficial to converting all elemental sulfur on the surface of the catalyst into the hydrogen sulfide, stopping activation after the gas-phase hydrogen sulfide is reduced to 1ppm, and almost completely recovering the performance of the activated catalyst.