A method for purifying sulfur paste to produce sulfur

Abstract

This invention discloses a method for purifying sulfur paste to prepare sulfur. The method involves feeding dehydrated sulfur paste and flocculant into a conical funnel via an inlet, where they move downwards and come into full contact with high-temperature steam ejected from a nozzle. Some unreacted high-temperature steam and the generated flue gas accumulate below the conical funnel. Under the action of a pump, the steam entering from the venturi tube and the steam inlet are fully mixed in the venturi tube and then re-injected into the high-temperature melting chamber. During this process, the sulfur paste is fully melted, and some volatile impurities are discharged from the exhaust port into the flue gas treatment system. The molten sulfur paste enters a rotary kiln from the bottom of the high-temperature melting chamber for further mixing and heating. The flocculant in the molten liquid mixes and flocculates the insoluble impurities in the sulfur paste. Finally, the mixed and heated sulfur paste solution is passed into a settling and stratification chamber. The insoluble impurities are flocculated and precipitated, and then discharged from the lower slag outlet. The upper clear liquid is discharged from the outlet. After filtration, condensation, and drying, high-purity sulfur is obtained. This invention provides a solution for the high-value utilization of sulfur resources in coke oven gas and natural gas.

Description

Technical Field

[0001] This invention belongs to the field of sulfur purification, specifically relating to a process and apparatus for purifying sulfur paste produced by desulfurization of coke oven gas complexed with iron to prepare sulfur. Background Technology

[0002] Sulfur, the main component of coking sulfur paste, is used in the production of high-grade asphalt for vulcanized modified roads, exhibiting excellent high-temperature rutting resistance and fatigue cracking resistance. Meanwhile, desulfurization catalysts and tar-like substances are unique components of coking sulfur paste. During the asphalt modification process, the desulfurization catalysts can inhibit the release of pollutants such as H2S during mixing, while polycyclic tar-like substances can increase the stability of the asphalt colloid. Therefore, coking sulfur paste, after appropriate treatment, can be used as a high-quality raw material for asphalt modification.

[0003] Current methods for treating coking sulfur paste generally suffer from problems such as high energy consumption, large investment, complex operation, flammable and explosive raw materials, secondary pollution, and poor product quality, which limit their large-scale application. Therefore, research on new technologies for the resource-based treatment and utilization of coking sulfur paste is urgently needed. Summary of the Invention

[0004] This invention provides a method for purifying sulfur paste to prepare sulfur, which is used for purifying sulfur in sulfur paste produced by desulfurization of coke oven gas complexed with iron.

[0005] The method for purifying sulfur paste to prepare sulfur according to the present invention is as follows:

[0006] 1. The sulfur paste produced in the desulfurization of coke oven gas complexed iron is dehydrated and mixed with flocculant, and added to the purification device through the feed inlet. The sulfur paste waste enters the conical funnel from the feed inlet and moves downward, and is fully heated by the high-temperature steam sprayed from the nozzle. Some of the unreacted high-temperature steam and the generated flue gas gather at the bottom of the conical funnel. Under the action of the air pump, the steam entering from the venturi tube and the steam entering from the steam inlet are fully mixed in the venturi tube and then re-injected into the high-temperature melting chamber. During this process, the sulfur paste is fully dissolved, and some volatile impurities are discharged from the exhaust port and enter the flue gas treatment system.

[0007] The purification device includes an inclined shell, inside which are arranged a high-temperature melting chamber, a rotary kiln, and a settling and stratifying chamber. The rotary kiln is located between the high-temperature melting chamber and the settling and stratifying chamber. The top of the high-temperature melting chamber is provided with a feed inlet and an exhaust port. A one-way feed valve is provided on the feed inlet. One or more conical funnels are provided below the feed inlet. An air pump is connected to the high-temperature melting chamber through a pipe, with the connection point located below the conical funnels. The air pump is connected to multiple nozzles through a Venturi tube and a pipe. The steam inlet is located on the Venturi tube. The nozzles are located below the conical funnels. The bottom of the high-temperature melting chamber is connected to the rotary kiln. The liquid outlet of the rotary kiln is connected to the settling and stratifying chamber. A slag discharge port is provided at the bottom of the settling and stratifying chamber, and a discharge port is provided in the middle.

[0008] 2. The molten sulfur paste liquid enters the rotary kiln from the bottom of the high-temperature melting chamber for thorough heating and mixing. The generated volatile gases and some SO2 enter the flue gas treatment system through the upper outlet, the high-temperature melting chamber, and the exhaust port. During this process, the insoluble impurities in the sulfur paste mixture are fully flocculated.

[0009] 3. The sulfur paste mixture after mixing and heating enters the settling and stratification chamber from the rotary kiln for settling and stratification. The mixture of insoluble impurities is precipitated and discharged from the bottom slag discharge port, while the upper clear liquid is discharged from the discharge port. After filtration, condensation and drying, the upper clear liquid yields high-purity sulfur.

[0010] The sulfur paste mentioned is a type of sulfur paste produced during the desulfurization process of natural gas and coal gas complexed iron.

[0011] The rotary kiln rotates at a speed of 1.0 to 1.5 r / min.

[0012] The flocculant is one or more of polyaluminum chloride, polyferric sulfate, polyacrylamide, polyacetamide, polyacrylic acid and polyacrylic sulfonic acid, and the amount of flocculant added is 0.02~2.0% of the mass of sulfur paste.

[0013] The steam temperature is 130~360℃, the steam pressure is 0.1~1.5MPa, the flow rate is 2~5L / kg sulfur paste, and the residence time of the sulfur paste mixture in the rotary kiln is 20~90 min.

[0014] The method of this invention achieves efficient purification of sulfur paste waste generated from the desulfurization of coke oven gas complexed iron through a combination of processes such as high-temperature melting, mixing and flocculation, and supernatant filtration and drying using a short-process technology and equipment. This provides a solution for the high-value utilization of sulfur resources in coke oven gas and natural gas. Attached Figure Description

[0015] Figure 1 This invention relates to an apparatus for purifying sulfur paste to prepare sulfur.

[0016] In the diagram: 1-rotary kiln; 2-conical funnel; 3-one-way feed valve; 4-feed inlet; 5-vent hole; 6-steam inlet; 7-air pump; 8-venturi tube; 9-nozzle; 10-discharge port; 11-slag discharge port; 12-baffle. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, but the scope of protection of the present invention is not limited to the content described herein;

[0018] like Figure 1As shown, the purification device used in the following embodiments includes an inclined shell, inside which are arranged a high-temperature melting chamber, a rotary kiln, and a settling and stratifying chamber. The rotary kiln is located between the high-temperature melting chamber and the settling and stratifying chamber. A baffle 12 is arranged between the high-temperature melting chamber and the rotary kiln. The upper part of the baffle 12 is the rotary kiln's air outlet, and the lower part is the rotary kiln's liquid inlet. Two conical funnels 2 are fixed on the baffle 12. The top of the high-temperature melting chamber is provided with a feed inlet 4 and an exhaust port 5. A one-way feed valve 3 is provided on the feed inlet. The conical funnel 2 is located below the feed inlet 4. An air pump 7 is connected to the high-temperature melting chamber through a pipe, and the connection point is located below the first conical funnel 2. The air pump 7 is connected to multiple nozzles 9 through a venturi tube 8 and a pipe. A steam inlet 6 is provided on the venturi tube 8, and the nozzles 9 are provided below the conical funnels 2. The bottom of the high-temperature melting chamber is connected to the liquid inlet of the rotary kiln 1, and the liquid outlet of the rotary kiln 1 is connected to the settling and stratifying chamber. A slag discharge port 11 is provided at the bottom of the settling and stratifying chamber, and a discharge port 10 is provided in the middle.

[0019] Sulfur paste and flocculant enter the conical funnel 2 through the feed inlet and move downwards, fully contacting and heating with the high-temperature steam sprayed from the nozzle 9. Some unreacted high-temperature steam and the generated flue gas gather below the conical funnel 2. Under the action of the air pump 7, the steam entering from the venturi tube 8 and the steam entering from the steam inlet 6 are fully mixed in the venturi tube and then re-sprayed into the high-temperature melting chamber. During this process, the sulfur paste is fully melted, and some volatile impurities are discharged from the exhaust port 5 and enter the flue gas treatment system. The molten sulfur paste enters the rotary kiln 1 from the bottom of the high-temperature melting chamber for further mixing and heating. The flocculant in the molten liquid mixes and flocculates the insoluble impurities in the sulfur paste. Finally, the sulfur paste mixture after mixing and heating is passed into the settling and stratification chamber. The mixture of insoluble impurities is flocculated and precipitated and discharged from the lower slag discharge port 11. The upper clear liquid is discharged from the discharge port 12. After filtration, condensation and drying, high-purity sulfur is obtained.

[0020] Example 1: Method for purifying sulfur paste to prepare sulfur

[0021] The sulfur paste produced by desulfurization using coke oven gas complexing iron method is purified after dehydration. The flocculant added to the sulfur paste is polyacetamide and polyferric chloride (mass ratio 1:1), with the flocculant addition amount being 0.08% of the sulfur paste mass. The steam temperature is 130℃, the steam pressure is 0.5 MPa, the steam injection flow rate is 2 L / kg sulfur paste, and the rotary kiln speed is 1.0 r / min. After the sulfur paste mixture melts and enters the rotary kiln for post-treatment for 30 min, the pipeline valve at the rear end of the rotary kiln is opened to allow the sulfur mixture to flow into the settling and stratification chamber. When the sulfur paste mixture settles until the upper liquid solution is golden yellow, the discharge valve is opened to collect the liquid sulfur. The collected liquid sulfur is cooled and dried to obtain the purified sulfur product with a sulfur purity of 85% and a recovery rate of 83%. Example 2

[0022] The sulfur paste produced by desulfurization using coke oven gas PDS + tannin method was purified after dehydration. The flocculant added to the sulfur paste was polyacrylamide and polyferric sulfate (mass ratio 2:1), with the flocculant dosage being 0.1% of the sulfur paste mass. The steam temperature was 150℃, the steam pressure was 1.0 MPa, the steam injection flow rate was 3.0 L / kg sulfur paste, and the rotary kiln speed was 1.2 r / min. After the sulfur paste mixture melted and entered the rotary kiln for 60 min of post-treatment, the pipeline valve at the rear end of the rotary kiln was opened to allow the sulfur mixture to flow into the settling unit. When the sulfur paste mixture settled until the upper liquid layer turned golden yellow, the discharge valve was opened to collect the liquid sulfur. The collected liquid sulfur was cooled and dried to obtain the purified sulfur product with a sulfur purity of 89.6% and a recovery rate of 85.3%. Example 3

[0023] The sulfur paste produced by natural gas complex iron desulfurization was purified after dehydration. The flocculant added to the sulfur paste was polyacrylamide and polyferric sulfate (mass ratio 1.5:1), with the flocculant addition amount being 1.5% of the sulfur paste mass. The steam temperature was 250℃, the steam pressure was 1.5 MPa, the steam injection flow rate was 4.0 L / kg sulfur paste, and the rotary kiln speed was 1.5 r / min. After the sulfur paste mixture melted and entered the rotary kiln for 90 min of post-treatment, the sulfur mixture was then allowed to flow into the settling unit. When the sulfur paste mixture settled until the upper liquid solution turned golden yellow, the discharge valve was opened to collect the liquid sulfur. The collected liquid sulfur was cooled and dried to obtain the purified sulfur product with a sulfur purity of 96.8% and a recovery rate of 89.3%.

Claims

1. A method for purifying sulfur paste to prepare sulfur, characterized in that: Dehydrated sulfur paste and flocculant are added to the purification device through the feed inlet (4). The purification device includes an inclined shell, a high-temperature melting chamber, a rotary kiln, and a static stratification chamber. The rotary kiln is located between the high-temperature melting chamber and the static stratification chamber. The top of the high-temperature melting chamber is provided with a feed inlet (4) and an exhaust port (5). A one-way feed valve (3) is provided on the feed inlet. One or more conical funnels (2) are provided below the feed inlet (4). An air pump (7) is connected to the high-temperature melting chamber through a pipe and the connection point is located below the conical funnel (2). The air pump (7) is connected to multiple nozzles (9) through a venturi tube (8) and a pipe. A steam inlet (6) is provided on the venturi tube (8). The nozzles (9) are provided below the conical funnel (2). The bottom of the high-temperature melting chamber is connected to the rotary kiln (1). The outlet of the rotary kiln (1) is connected to the static stratification chamber. A slag discharge port (11) is provided at the bottom of the static stratification chamber and a discharge port (10) is provided in the middle. Sulfur paste and flocculant enter the conical funnel (2) from the feed inlet and move downwards, fully contacting and heating with the high-temperature steam sprayed from the nozzle (9). Some unreacted high-temperature steam and generated flue gas gather below the conical funnel (2). Under the action of the air pump (7), it is fully mixed with the steam entering from the steam inlet (6) in the venturi tube and then re-sprayed into the high-temperature melting chamber. During this process, the sulfur paste is fully melted, and some volatile impurities are discharged from the exhaust port (5) into the flue gas treatment system. The molten sulfur paste mixture enters the rotary kiln (1) from the bottom of the high-temperature melting chamber for further mixing and heating. The flocculant in the molten liquid mixes and flocculates the insoluble impurities in the sulfur paste. Finally, the mixed sulfur paste mixture is passed into the static stratification chamber. The mixture of insoluble impurities is precipitated and discharged from the lower slag discharge port (11). The upper clear liquid is discharged from the discharge port (10). After filtration, condensation and drying, high-purity sulfur is obtained.

2. The method for purifying sulfur paste to prepare sulfur according to claim 1, characterized in that: The flocculant is one or more of polyaluminum chloride, polyacrylamide, polyacetamide, polyacrylic acid and polyacrylamide sulfonic acid, polyaluminum chloride and polyferric sulfate, and the amount of flocculant added is 0.02~2.0% of the mass of sulfur paste.

3. The method for purifying sulfur paste to prepare sulfur according to claim 1, characterized in that: The steam temperature is 130~360℃, the steam pressure is 0.1~1.5MPa, and the residence time of the molten sulfur paste mixture in the rotary kiln is 20~90 min.

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