A process and system for producing sulfur from gas by using recyclable hydrogen sulfide adsorbent

Abstract

The invention discloses a process and system for preparing sulfur from decomposed gas with a recyclable hydrogen sulfide adsorbent, comprising the steps of heating and decomposing a saturated hydrogen sulfide adsorbent with sulfur-free clean coal gas to obtain decomposed gas; heating the decomposed gas and performing a COS conversion reaction to generate hydrogen sulfide gas; oxidizing and heating a portion of the obtained hydrogen sulfide gas in sequence, and performing a catalytic reaction with another portion of the remaining gas; cooling the gas after the reaction, condensing sulfur vapor into powder crystals, and collecting the condensed sulfur vapor to obtain sulfur; the system comprises a heat storage device, a COS conversion tower, and an H 2 S oxidation tower, heating device, SO 2 Conversion tower and sulfur collection tower. The present invention uses a small amount of sulfur-free purified coal gas to analyze the hydrogen sulfide adsorbent, and the obtained analytical gas is processed in sections and concentratedly to obtain sulfur and collect it, effectively reducing the gas volume of blast furnace gas source desulfurization treatment and effectively improving the sulfur yield.

Description

Technical Field

[0001] The invention relates to the technical field of atmosphere purification and environmental protection, and in particular to a process and system for preparing sulfur from gas by using a recyclable hydrogen sulfide adsorbent. Background Art

[0002] The blast furnace gas source desulfurization process has been successfully used in many domestic steel mills. The existing desulfurization process generally converts COS in the gas into H2S first, then adsorbs the H2S, or directly partially oxidizes it into sulfur for recovery. The former will analyze the adsorbent saturated with adsorption, and the analyzed sulfur-containing gas will enter the sintering process for post-treatment. This approach does not achieve a true desulfurization effect. The latter uses sulfur generated by hydrogen sulfide as a partial oxidant, but since the sulfur content in blast furnace gas is 200mgS / Nm 3 About 1280m 3 A blast furnace can produce more than 400,000 cubic meters of blast furnace gas per hour, but the total amount of sulfur is generally only about tens of kilograms. If this partial oxidant is used directly to prepare sulfur, all the blast furnace gas must be heated to the working temperature of the partial oxidation catalyst, which is generally above 200°C. It can be seen how much energy is wasted by heating hundreds of thousands of cubic meters of gas to above 200°C in order to recover tens of kilograms of sulfur. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides a process and system for producing sulfur from desorbed gas using a recyclable hydrogen sulfide adsorbent. By analyzing the characteristics of the desorbed gas produced by the adsorbent and adopting a staged treatment method, the desulfurization efficiency and sulfur yield of blast furnace gas are greatly improved.

[0004] The present invention adopts the following technical solution:

[0005] On the one hand, the present invention provides a process for preparing sulfur from decomposed gas using a recyclable hydrogen sulfide adsorbent, comprising: heating and decomposing a saturated hydrogen sulfide adsorbent with sulfur-free clean coal gas to obtain decomposed gas; heating the decomposed gas and generating hydrogen sulfide gas through a COS conversion reaction; oxidizing and heating a portion of the obtained hydrogen sulfide gas in turn, and subjecting the portion to a catalytic reaction with the remaining gas; cooling the reacted gas to condense sulfur vapor into powder crystals and collecting the resulting sulfur.

[0006] Preferably, when the desorption gas satisfies both the heating temperature being higher than 150° C. and the sulfur content in the desorption gas being higher than 200 ppm, hydrogen sulfide gas is generated through the COS conversion reaction.

[0007] Furthermore, when the desorption gas is heated to a temperature of 180 to 220° C., hydrogen sulfide gas is generated through a COS conversion reaction.

[0008] Preferably, a portion of the hydrogen sulfide gas that has been oxidized and heated accounts for 80-95% of all generated hydrogen sulfide gas, and the remaining portion of the gas accounts for 5-20% of all generated hydrogen sulfide gas.

[0009] Furthermore, a part of the obtained hydrogen sulfide gas is oxidized and then heated at a temperature of 250-280°C.

[0010] Preferably, the COS conversion reaction generates hydrogen sulfide gas, the catalyst carrier used is one or more composites of carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active component used is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium oxalate, potassium oxalate, sodium sulfate, and potassium sulfate.

[0011] Preferably, a portion of the gas in the obtained hydrogen sulfide gas is oxidized in sequence, the catalyst carrier used is one or more composites of modified bauxite, carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active component used is one or more of ferric nitrate, cobalt nitrate, nickel nitrate, ferric sulfate, cobalt sulfate, nickel sulfate, ferric chloride, cobalt chloride, nickel chloride, ferric oxalate, cobalt oxalate, nickel oxalate, copper nitrate, copper acetate, copper chloride, and copper sulfate.

[0012] Preferably, after a part of the obtained hydrogen sulfide gas is oxidized and heated in sequence, and then catalytically reacted with another part of the remaining gas, the catalyst carrier used is one or more composites of modified bauxite, magnesia spinel, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide.

[0013] On the other hand, the present invention also provides a system for producing sulfur from decomposed gas using a recyclable hydrogen sulfide adsorbent, which is connected to a hydrogen sulfide adsorption tower. The system includes a heat storage device, a COS conversion tower, an H2S oxidation tower, a heating device, an SO2 conversion tower and a sulfur collection tower. The heat storage device is connected to the gas outlet of the hydrogen sulfide adsorption tower and is used to heat the decomposed gas; the gas outlet of the heat storage device is connected to the gas inlet of the COS conversion tower, and the gas outlet of the COS conversion tower is connected to the gas inlets of the H2S oxidation tower and the SO2 conversion tower through pipelines, respectively; the gas inlet of the heating device is connected to the gas outlet of the H2S oxidation tower, and the gas outlet of the heating device is connected to the gas inlet of the SO2 conversion tower; the gas outlet of the SO2 conversion tower is connected to the gas inlet end of the sulfur collection tower, and the COS conversion tower, the H2S oxidation tower and the SO2 conversion tower are respectively provided with corresponding catalyst carriers.

[0014] Furthermore, a low-sulfur gas outlet is provided on the side of the sulfur collection tower, and the gas outlet of the heat storage device and the low-sulfur gas outlet are respectively connected to the gas network through pipelines.

[0015] The technical solution of the present invention has the following advantages:

[0016] A. The present invention uses a small amount of sulfur-free purified coal gas to perform analytical treatment on the hydrogen sulfide adsorbent, and performs independent and continuous segmented centralized treatment on the obtained analytical gas to obtain and collect sulfur, thereby effectively reducing the gas volume of blast furnace gas source desulfurization treatment and improving the sulfur yield.

[0017] B. After the COS conversion reaction, the present invention divides the generated hydrogen sulfide gas into two parts, one part of which is oxidized and heated to undergo a catalytic reaction with the other part of the remaining hydrogen sulfide gas that has not participated in the oxidation, to produce sulfur vapor and condense into sulfur powder crystals. The process energy consumption is effectively reduced through segmented heat storage and heat reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A process block diagram of the invention for producing sulfur from recyclable hydrogen sulfide adsorbent gas;

[0020] Figure 2 A schematic diagram of the structural composition of a system for producing sulfur from recyclable hydrogen sulfide adsorbent gas provided by the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] like Figure 1 As shown, the present invention provides a process for preparing sulfur from gas by using a recyclable hydrogen sulfide adsorbent, and the process comprises the following steps:

[0025] [S01] The saturated hydrogen sulfide adsorbent is heated and analyzed by sulfur-free clean coal gas to obtain analyzed gas.

[0026] When the desorption gas is heated, the temperature of the desorption gas reaches 180 to 220°C.

[0027] [S02] The analytical gas is heated and converted into hydrogen sulfide gas through a COS conversion reaction.

[0028] The catalyst carrier used in the COS conversion reaction is one or more composites of carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active component used is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium oxalate, potassium oxalate, sodium sulfate, and potassium sulfate.

[0029] When the desorption gas meets the conditions of heating temperature higher than 150℃ and sulfur content higher than 200ppm, hydrogen sulfide gas is generated through COS conversion reaction. Otherwise, if the heating temperature is lower than 150℃, or the sulfur content in the desorption gas is lower than 200ppm, COS conversion reaction cannot be carried out, but it is directly discharged from the bypass.

[0030] [S03] A portion of the obtained hydrogen sulfide gas is oxidized and heated in sequence, and then catalytically reacted with another portion of the remaining gas.

[0031] A portion of the gas is oxidized, and the catalyst carrier used is one or more complexes of modified bauxite, carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active components used are one or more of ferric nitrate, cobalt nitrate, nickel nitrate, ferric sulfate, cobalt sulfate, nickel sulfate, ferric chloride, cobalt chloride, nickel chloride, ferric oxalate, cobalt oxalate, nickel oxalate, copper nitrate, copper acetate, copper chloride, and copper sulfate.

[0032] When the two parts of gas are subjected to catalytic reaction, the catalyst carrier used is one or more composites of modified bauxite, magnesium aluminum spinel, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide.

[0033] A portion of the hydrogen sulfide gas that has been oxidized and heated accounts for 80-95% of all generated hydrogen sulfide gas, and the remaining portion of the gas accounts for 5-20% of all generated hydrogen sulfide gas.

[0034] A part of the obtained hydrogen sulfide gas is oxidized and then heated at a temperature of 250 to 280°C.

[0035] [S04] The gas after the reaction is cooled to condense the sulfur vapor into powder crystals and then collected to obtain sulfur.

[0036] The present invention can greatly improve the desulfurization efficiency and sulfur yield of blast furnace gas by analyzing the characteristics of the desorbed gas produced by the adsorbent and adopting a segmented treatment method. The principle is as follows: the desorption process of the adsorbent can be divided into three stages. The first stage is from 60 to 150°C, almost no sulfide is desorbed, and this stage accounts for about 1 / 5 of the total time; the second stage is from 150 to 250°C, a large amount of sulfide is desorbed, and its concentration is sometimes as high as 3.5%, and this stage accounts for about 1 / 3 of the total time; the third stage is when the desorbed sulfide is lower than 200ppm, and this stage accounts for about 1 / 3 of the total time; the last time is used for cooling the adsorbent. The total time to complete the entire sulfur production process after the desorbed gas enters the COS conversion tower is about 10h to 14h.

[0037] like Figure 2 As shown, the present invention also provides a recyclable system for preparing sulfur from desorbed gas using hydrogen sulfide adsorbent, which is connected to a hydrogen sulfide adsorption tower, and the system includes a heat storage device, a COS conversion tower, an H2S oxidation tower, a heating device, an SO2 conversion tower, and a sulfur collection tower. The heat storage device is connected to the gas outlet of the hydrogen sulfide adsorption tower, and is used to heat the desorbed gas; the gas outlet of the heat storage device is connected to the gas inlet of the COS conversion tower, and the gas outlet of the COS conversion tower is connected to the gas inlets of the H2S oxidation tower and the SO2 conversion tower through pipelines, respectively, and the amount of gas entering the H2S oxidation tower and the SO2 conversion tower can be distributed through a flow regulating valve arranged on the pipeline; the gas inlet of the heating device is connected to the gas outlet of the H2S oxidation tower, and the gas outlet of the heating device is connected to the gas inlet of the SO2 conversion tower; the gas outlet of the SO2 conversion tower is connected to the gas inlet end of the sulfur collection tower, and corresponding catalyst carriers are respectively arranged in the COS conversion tower, the H2S oxidation tower, and the SO2 conversion tower.

[0038] The present invention provides a low-sulfur gas outlet (not shown in the figure) on the side of the sulfur collection tower, and the gas outlet of the heat storage device and the low-sulfur gas outlet are respectively connected to the gas network through pipelines, and the low-sulfur gas returns to the gas network for further circulation treatment; for the analysis gas coming out of the heat storage device, when its temperature is lower than 150°C, or when the sulfur content in the analysis gas is lower than 200ppm, it does not enter the COS conversion tower, but directly comes out from the bypass and returns to the gas network.

[0039] The heat storage device, COS conversion tower, H2S oxidation tower, heating device, SO2 conversion tower and sulfur collection tower mentioned above can all adopt existing equipment, and the structure and principle of the relevant equipment will not be repeated here.

[0040] Example 1

[0041] 40 tons of coal-made activated carbon was used to 3 / h, 80℃, COS concentration is 180mg / m 3 When the adsorbent is saturated, use 4000Nm 3 / h of clean sulfur-free blast furnace gas is used to analyze and regenerate the adsorbent. When the temperature of the analytical gas reaches 150℃, it begins to enter the COS conversion tower equipped with Na2CO3 / Ti-Al2O3 catalyst to convert COS in the analytical gas into hydrogen sulfide. After diversion treatment, 90% of the gas enters the H2S oxidation tower equipped with Fe / SiO2 catalyst for oxidation treatment. After the treated gas is heated to 250℃, it enters the SO2 conversion tower equipped with a-Al2O3 catalyst; the other 10% of the gas enters the SO2 conversion tower directly without oxidation treatment. These two groups of gases further react to generate sulfur in the SO2 conversion tower. The gas after the reaction in the SO2 conversion tower is cooled to 80℃ in the sulfur collector, and the sulfur vapor is cooled in the collector to generate sulfur powder, which is deposited at the bottom. The low-sulfur gas returns to the gas pipeline network for further circulation treatment. When the sulfur content at the H2S test port is lower than 200mg / m 3 During this cycle, the desorption gas no longer passes through the COS conversion tower, but directly passes through the return pipe network from the bypass. During this cycle, the total time for the desorption gas to enter the COS conversion tower is about 10 hours, the total gas processing volume is about 40,000 cubic meters, the sulfur collection volume is about 1,215 kg, and the sulfur yield is about 82%.

[0042] Example 2

[0043] 60 tons of coal-made activated carbon was used to 3 / h, 70℃, COS concentration is 190mg / m 3 When the adsorbent is saturated, use 5000Nm 3 / h of clean sulfur-free blast furnace gas is used to analyze and regenerate the adsorbent. When the temperature of the analyzed gas reaches 150℃, it begins to enter the COS conversion tower equipped with K2CO3 / Al2O3 catalyst to convert COS in the analyzed gas into hydrogen sulfide. After diversion treatment, 95% of the gas enters the H2S oxidation tower equipped with Fe / Ce / SiO2 catalyst for oxidation treatment. After the treated gas is heated to 260℃, it enters the SO2 conversion tower equipped with magnesium aluminum spinel catalyst; the other 5% of the gas enters the SO2 conversion tower directly without oxidation treatment. These two groups of gases further react to generate sulfur in the SO2 conversion tower. The gas after the reaction in the SO2 conversion tower is cooled to 70℃ in the sulfur collector, and the sulfur vapor is cooled in the collector to generate sulfur powder, which is deposited at the bottom. The low-sulfur gas returns to the gas pipeline network for further circulation treatment. When the sulfur content at the H2S test port is lower than 200mg / m 3 During this cycle, the desorption gas no longer passes through the COS conversion tower, but directly passes through the return pipe network from the bypass. During this cycle, the total time for the desorption gas to enter the COS conversion tower is about 14 hours, the total gas processing volume is about 70,000 cubic meters, the amount of sulfur collected is about 1,723 kilograms, and the sulfur yield is about 85%.

[0044] Example 3

[0045] 30 tons of coal-made activated carbon was used to 3 / h, 75℃, COS concentration is 200mg / m 3 When the adsorbent is saturated, use 3000Nm 3 / h of clean sulfur-free blast furnace gas is used to analyze and regenerate the adsorbent. When the temperature of the analyzed gas reaches 150℃, it is introduced into the COS conversion tower equipped with K2CO3 / Ti / Al2O3 catalyst to convert COS in the analyzed gas into hydrogen sulfide. After diversion treatment, 80% of the gas enters the H2S oxidation tower equipped with Fe / Co / SiO2 catalyst for oxidation treatment. After the treated gas is heated to 280℃, it enters the SO2 conversion tower equipped with zirconium oxide catalyst; the other 12% of the gas enters the SO2 conversion tower directly without oxidation treatment. These two groups of gases further react to generate sulfur in the SO2 conversion tower. The gas after the reaction in the SO2 conversion tower is cooled to 80℃ in the sulfur collector, and the sulfur vapor is cooled in the collector to generate sulfur powder, which is deposited at the bottom. The low-sulfur gas returns to the gas pipeline network for further circulation treatment. When the sulfur content at the H2S test port is lower than 200mg / m 3 During this cycle, the desorption gas no longer passes through the COS conversion tower, but directly passes through the return pipe network from the bypass. During this cycle, the total time for the desorption gas to enter the COS conversion tower is about 13 hours, the total gas processing volume is about 40,000 cubic meters, the amount of sulfur collected is about 1011 kg, and the sulfur yield is about 86%.

[0046] Any matters not described in the present invention are applicable to the prior art.

[0047] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A process for preparing sulfur from gas by using a recyclable hydrogen sulfide adsorbent, characterized in that: The saturated hydrogen sulfide adsorbent is heated and decomposed by sulfur-free clean coal gas to obtain decomposed gas; the decomposed gas is heated and converted into hydrogen sulfide gas by COS reaction; a part of the obtained hydrogen sulfide gas is oxidized and heated in sequence, and then catalytically reacted with another part of the remaining gas; the gas after the reaction is cooled to condense sulfur vapor into powder crystals and then collected to obtain sulfur; When the desorption gas meets the conditions that the heating temperature is higher than 150℃ and the sulfur content in the desorption gas is higher than 200ppm, hydrogen sulfide gas is generated through the COS conversion reaction; A part of the hydrogen sulfide gas after oxidation and heating treatment accounts for 80-95% of all generated hydrogen sulfide gas, and the other part of the remaining gas accounts for 5-20% of all generated hydrogen sulfide gas.

2. The process for preparing sulfur from gas by using recyclable hydrogen sulfide adsorbent according to claim 1, characterized in that: When the desorption gas is heated to a temperature of 180 to 220°C, COS conversion reaction is performed to generate hydrogen sulfide gas.

3. The process for preparing sulfur from gas by using recyclable hydrogen sulfide adsorbent according to claim 1, characterized in that: A part of the obtained hydrogen sulfide gas is oxidized and then heated at a temperature of 250 to 280°C.

4. The process for preparing sulfur from gas by using recyclable hydrogen sulfide adsorbent according to claim 1, characterized in that: The COS conversion reaction generates hydrogen sulfide gas, and the catalyst carrier used is one or more composites of carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active component used is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium oxalate, potassium oxalate, sodium sulfate, and potassium sulfate.

5. The process for preparing sulfur from gas by using recyclable hydrogen sulfide adsorbent according to claim 1, characterized in that: The method comprises the following steps of sequentially subjecting a portion of the obtained hydrogen sulfide gas to oxidation treatment, wherein the catalyst carrier used is one or more composites of modified bauxite, carbon nitride, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide, and the loaded active component used is one or more of ferric nitrate, cobalt nitrate, nickel nitrate, ferric sulfate, cobalt sulfate, nickel sulfate, ferric chloride, cobalt chloride, nickel chloride, ferric oxalate, cobalt oxalate, nickel oxalate, copper nitrate, copper acetate, copper chloride, and copper sulfate.

6. The process for preparing sulfur from gas by using recyclable hydrogen sulfide adsorbent according to claim 1, characterized in that: The method comprises the following steps: first, oxidizing and heating a part of the obtained hydrogen sulfide gas in turn, and then subjecting it to a catalytic reaction with another part of the remaining gas. The catalyst carrier used is one or more composites of modified bauxite, magnesia-alumina spinel, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, zirconium oxide, and cerium oxide.

7. A system for preparing sulfur from gas by using a recyclable hydrogen sulfide adsorbent, which is connected to a hydrogen sulfide adsorption tower, characterized in that: The system includes a heat storage device, a COS conversion tower, an H2S oxidation tower, a heating device, an SO2 conversion tower and a sulfur collection tower. The heat storage device is connected to the gas outlet of the hydrogen sulfide adsorption tower for heating the analyzed gas; the gas outlet of the heat storage device is connected to the gas inlet of the COS conversion tower, and the gas outlet of the COS conversion tower is respectively connected to the gas inlets of the H2S oxidation tower and the SO2 conversion tower through pipelines; the gas inlet of the heating device is connected to the gas outlet of the H2S oxidation tower, and the gas outlet of the heating device is connected to the gas inlet of the SO2 conversion tower; the gas outlet of the SO2 conversion tower is connected to the gas inlet end of the sulfur collection tower, and the COS conversion tower, the H2S oxidation tower and the SO2 conversion tower are respectively provided with corresponding catalyst carriers.

8. The recyclable system for producing sulfur from hydrogen sulfide adsorbent gas according to claim 7, characterized in that: A low-sulfur gas outlet is provided on the side of the sulfur collection tower, and the gas outlet of the heat storage device and the low-sulfur gas outlet are respectively connected to the gas network through pipelines.

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