System for recovering sulfur from molten sulfur filter residues

Abstract

The utility model discloses a system for recovering sulfur from molten sulfur filter residues. The discharging end of the feeding belt is communicated with a feeding port of the crusher, a feeder is arranged below a discharging port of the crusher, a stock bin is arranged at the upper part of the feeder and is positioned at the lower part of the crusher, a discharging port of the feeder is communicated with the evaporation kettle, a heater is arranged on the outer side of the evaporation kettle, and the top of the evaporation kettle is communicated with a liquid sulfur cooling separator, a venturi tube and a washing tower (12) through pipelines. The sulfur in the molten sulfur filter slag can be quickly and effectively recovered, and the method is simple to operate, high in sulfur recovery efficiency, small in environmental pollution, small in operation load, low in equipment maintenance rate, wide in application range and easy to industrialize, and has no requirement on the content of sulfur in the molten sulfur filter slag.

Description

Technical Field

[0001] The utility model belongs to the field of chemical industry and relates to a system for recovering sulfur from molten sulfur filtering residue. Background Art

[0002] Currently, sulfur melting equipment is used in the domestic production of sulfuric acid from sulfur. The main process involves evenly coating the filter screen with diatomaceous earth to create a filter layer. The solid sulfur is melted and then filtered through the filter layer to remove impurities. After filtration, the sulfur impurities are reduced to below 20ppm. After the impurities accumulate within the filter layer for a certain period of time, they are removed and a new filter layer is applied. The old filter layer is replaced with a dark brown cement-like filter residue containing approximately 68% sulfur.

[0003] According to statistics, my country's sulfuric acid production capacity in 2022 was 129.5 million tons, of which sulfuric acid production accounted for 44.12%. The filtered sulfur required was 57.1354 million tons. As of 2022, the molten sulfur filter residue produced was 577,100 tons (molten sulfur filter residue accounted for about 1% of the total sulfur amount), of which 392,400 tons contained pure sulfur. The treatment of these filter residues as solid waste caused waste of resources and environmental impact.

[0004] At present, the molten sulfur filter residue produced by domestic enterprises in producing sulfuric acid from sulfur is difficult to handle, and most of it requires a certain amount of money to entrust other environmental protection companies or pyrite acid production equipment to handle it, which increases the cost of sulfuric acid production for enterprises. Utility Model Content

[0005] The utility model aims to provide a system for recovering sulfur from molten sulfur filtering residue, which has high sulfur recovery rate, small environmental pollution, simple device, no requirement for the elemental sulfur content in the molten sulfur filtering residue, and high economic benefit.

[0006] The technical solution of this utility model is:

[0007] A system for recovering sulfur from molten sulfur filter residue, the system comprising a feed belt, the discharge end of the feed belt being connected to the feed port of a crusher, a feeder being provided below the crusher discharge port, a hopper being located above the feeder, the hopper being located below the crusher, the feeder discharge port being connected to an evaporator, a heater being provided on the outside of the evaporator, a nitrogen pipeline being provided at the top of the evaporator through a pipeline connected to a liquid sulfur cooling separator, a venturi, and a washing tower, for introducing nitrogen into the evaporator, thereby effectively preventing sulfur from being oxidized by oxygen in the air. The evaporator is provided with a level meter for controlling the feed so that the material in the evaporator is within the required range; a slag hopper at the lower end of the evaporator is connected to a waste screw, preferably provided with a level meter, which controls the speed of the waste screw through the level meter to ensure a certain material level in the slag hopper, thereby preventing air from entering the evaporator 04 from the waste screw 07 after complete emptying, causing sulfur combustion.

[0008] Further preferably, a water cooling spray device is provided on the outside of the waste spiral cylinder to cool the waste spiral including the residual slag inside.

[0009] Preferably, the evaporation kettle and the liquid sulfur cooling separator are connected via a pipeline, and the pipeline is provided with a steam insulation jacket to prevent the sublimated sulfur from solidifying and clogging the pipeline.

[0010] Preferably, the liquid sulfur cooling separator is equipped with a heat exchange pipeline, and the cooling medium is hot water. Thus, the temperature within the hot water cooling separator is controlled at 120-160°C, preventing the gaseous sulfur vapor from solidifying but not becoming too hot to condense and separate. The bottom of the liquid sulfur cooling separator is provided with a liquid sulfur tank, which is equipped with a liquid level gauge and a transfer pump. This allows the cooled and separated liquid sulfur to be collected, transported, and recycled.

[0011] Preferably, the top of the liquid sulfur cooling separator is connected to a venturi via a pipe. Preferably, the top of the liquid sulfur cooling separator is connected to the exhaust gas inlet at the upper middle portion of the venturi via a pipe, and the bottom of the venturi is connected to the water pool at the bottom of the scrubber. The top is sprayed with circulating water delivered by a circulating scrubber pump. This further separates elemental sulfur from the mixed gas exiting the liquid sulfur cooling separator. The separated mixed gas is almost entirely nitrogen, meets emission standards, and is discharged from the top of the scrubber.

[0012] Further preferably, the venturi tube and the liquid sulfur cooling separator are connected via a pipeline, and the pipeline is provided with a steam insulation jacket to prevent sulfur vapor from solidifying and clogging the pipeline.

[0013] Preferably, the scrubber tower comprises a cooling tower at its top and a water tank at its bottom. The water tank is connected to the venturi, cooling tower, and filter press plates via a circulating scrubbing pump. The scrubbing circulating water outlet from the water tank is divided into three parts: one to the venturi 11, one to the scrubber 12 for cooling, and one to the filter press plates 14. This scrubbing water can be used to scrub elemental sulfur from the mixed gas and then recycled after cooling.

[0014] Preferably, the liquid sulfur tank is connected to the melting sulfur filter press section through a pipeline, the liquid sulfur separated by the liquid sulfur cooling separator can be directly transported to the melting sulfur filter press section, and the sulfur filtered out by the washing tower can be used as raw sulfur for the sulfur melting device, thereby achieving effective application in industrial production.

[0015] The beneficial effects of the utility model are:

[0016] The utility model can quickly and effectively recover sulfur in the molten sulfur filtering residue, and the method is simple to operate, has high sulfur recovery efficiency, little pollution to the environment, low operating load, low equipment maintenance rate, has no requirements on the sulfur content in the molten sulfur filtering residue, has a wide range of applications, and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the system for recovering sulfur from molten sulfur filter residue.

[0018] In the figure: feed belt 01, crusher 02, feeder 03, evaporator 04, heater 05, liquid sulfur cooling separator 06, waste screw 07, nitrogen pipeline 08, hot water pipeline 09, liquid sulfur tank 10, venturi 11, circulating washing pump 13, washing tower 12, filter press plate 14. DETAILED DESCRIPTION

[0019] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0020] Example 1

[0021] A system for recovering sulfur from molten sulfur filter residue, the system comprising a feed belt 01, the discharge end of the feed belt 01 being connected to the feed port of a crusher 02, a feeder 03 being provided below the discharge port of the crusher 02, the upper portion of the feeder 03 being a silo, the silo being located below the crusher 02, the discharge port of the feeder 03 being connected to an evaporator 04, the outer side of the evaporator 04 being provided with a heater 05, the top of the evaporator 04 being connected to a liquid sulfur cooling separator 06, a venturi 11, and a washing tower 12 via a pipeline.

[0022] The feeding belt 01 transports the molten sulfur filter residue to the crusher 02, crushes the molten sulfur filter residue to obtain fine particles that are easy to heat transfer and transport; and the feeder 03, the upper part of the feeder 03 is a silo, the silo is located at the lower part of the crusher 02, the fine particles of molten sulfur filter residue crushed by the crusher 02 enter the silo, and are quantitatively fed through the feeder 03 to achieve continuous production.

[0023] According to an embodiment of the present invention, the filter residue is cleaned out from the molten sulfur filter and then naturally cooled into blocks, transported to the crusher 02 through the feed belt 01, crushed into powdery fine particles, and then enters the feeder hopper at the bottom of the crusher. The material level in the hopper is controlled within the required range by controlling the speed of the feed belt 01.

[0024] According to an embodiment of the present invention, the crusher 02 is provided with a feeding belt 01 for conveying the molten sulfur filter residue into the crusher 02 .

[0025] According to an embodiment of the present invention, the molten sulfur filter residue after crushing is fine particles, which then enter the feeder hopper and enter the evaporator 04 through the feeder. The hopper is provided with a level meter, and the material level in the hopper is controlled within the required range by controlling the speed of the feed belt 01.

[0026] According to an embodiment of the present invention, the feeder 03 is further designed with a scale to quantitatively and evenly add the filtered residue into the evaporating kettle 04.

[0027] According to an embodiment of the present invention, the evaporator 04 is further provided with a material level meter for controlling the feeding so that the material in the evaporator 04 is within a required range.

[0028] According to an embodiment of the present invention, after the molten sulfur filter residue enters the evaporator 04 through the feeder 03, the filter residue is indirectly heated by heating the wall of the evaporator 04 through the heater 05 in a nitrogen environment. In an environment of 400-500°C, the elemental sulfur can be effectively sublimated from the filter residue. At the same time, the steam sulfur is discharged from the upper part of the tail of the evaporator 04 and enters the liquid sulfur cooling and separation device 06. The residual residue is discharged from the slag discharge hopper at the lower part of the tail of the evaporator into the waste screw 07.

[0029] According to an embodiment of the present invention, a scraper is further provided in the evaporation kettle 04 for conveying the molten sulfur filter residue in the evaporation kettle to facilitate uniform heating.

[0030] According to an embodiment of the present invention, a heater 05 is further provided on the wall of the evaporator 04, and a temperature detection instrument is provided on the wall to control the operation of the heater so that the heating temperature of the heater 05 is controlled at 400-500° C. Thus, sulfur can be effectively sublimated from the molten sulfur filter residue.

[0031] According to an embodiment of the present invention, a nitrogen pipeline 08 is further connected to the evaporation kettle 04 for introducing nitrogen into the evaporation kettle 04, which can effectively prevent sulfur from being oxidized by oxygen in the air.

[0032] According to an embodiment of the present invention, a level meter is further provided at the slag discharge hopper at the lower end of the evaporator 04. The level meter controls the rotation speed of the waste screw 07 to ensure that the slag discharge hopper has a certain level, thereby preventing air from entering the evaporator 04 from the waste screw 07 after complete emptying, causing sulfur combustion.

[0033] According to an embodiment of the present invention, a water cooling spray device is further provided on the outside of the waste spiral 07 cylinder to cool the waste spiral 07 including the residual slag inside.

[0034] According to an embodiment of the present invention, the evaporator 04 and the liquid sulfur cooling separator 06 are connected via a pipeline, and the pipeline is provided with a steam insulation jacket to prevent the sublimated sulfur from solidifying and clogging the pipeline.

[0035] According to an embodiment of the present invention, the liquid sulfur cooling separator 06 is provided with a hot water pipeline 09, and the cooling medium is hot water. Thus, the temperature inside the hot water cooling separator is controlled at 120-160°C, so that the gaseous sulfur vapor neither solidifies nor becomes too hot to be condensed and separated.

[0036] According to an embodiment of the present invention, the liquid sulfur cooling and separation unit 06 is further provided with a liquid sulfur tank 10 at the bottom, which includes a liquid level gauge and a delivery pump. Thus, the liquid sulfur separated by cooling can be collected and delivered for recycling.

[0037] According to an embodiment of the present invention, the exhaust gas separated by the liquid sulfur cooling separator 06 is scrubbed in a venturi scrubber 11 before being discharged. The upper middle portion of the venturi 11 receives exhaust gas, while its bottom portion is connected to a water pool at the bottom of the scrubber. The top portion is sprayed with circulating water supplied by a circulating scrubber pump 13. This further separates elemental sulfur from the mixed gas exiting the liquid sulfur cooling separator. The separated mixed gas is almost entirely nitrogen, meeting emission standards, and is discharged from the top of the scrubber 12.

[0038] According to an embodiment of the present invention, the venturi tube 11 and the liquid sulfur cooling separator 06 are connected via a pipeline, and the pipeline is provided with a steam insulation jacket to prevent sulfur vapor from solidifying and clogging the pipeline.

[0039] According to an embodiment of the present invention, the scrubber 12 comprises a cooling tower at the top, a water tank at the bottom, and a circulating scrubber pump. The scrubber circulating water outlet is divided into three parts: one to the venturi 11, one to the scrubber 12 for cooling, and one to the filter press plate 14. This scrubber water can be used to scrub elemental sulfur from the mixed gas and then recycled after cooling.

[0040] According to an embodiment of the present invention, a part of the circulating washing pump 13 is further included to the filter press plate, the purpose of which is to filter out the elemental sulfur washed out by the venturi tube from the circulating water, and the circulating water after filtering is recycled to the washing tower.

[0041] According to the embodiment of the present invention, the liquid sulfur separated by the liquid sulfur cooling separator 06 can be directly transported to the sulfur melting and filter pressing section, and the sulfur filtered out by the washing tower 12 can be used as raw sulfur for the sulfur melting device, thereby achieving effective application in industrial production.

[0042] According to the embodiment of the present invention, the residue collected in the waste spiral contains less than 20% sulfur, and after cooling, it can be used for combustion recovery in devices such as pyrite acid production and coal-fired boiler production of ammonium sulfate, and has a wide range of applications.

[0043] The method for recovering sulfur from molten sulfur filtering residue of the utility model comprises the following steps:

[0044] Crushing of molten sulfur filter residue:

[0045] The filter residue is cleaned out from the molten sulfur filter and naturally cooled into blocks. It is then transported to the crusher through the feed belt and crushed into powdery fine particles. It then enters the feeder hopper at the bottom of the crusher. The material level in the hopper is controlled within the required range by controlling the feed belt speed.

[0046] The crusher is provided with a feeding belt for conveying the molten sulfur filter residue into the crusher.

[0047] The molten sulfur filter residue after crushing is fine particles, which then enter the feeder hopper and enter the evaporator through the feeder. The hopper is equipped with a level meter, which controls the material level in the hopper within the required range by controlling the speed of the feed belt.

[0048] The feed machine is designed to weigh and add the filtered residue evenly into the evaporator in a quantitative manner.

[0049] The evaporator is equipped with a material level meter. When the material level is too high, the feeder will be stopped to avoid blockage.

[0050] Filter residue heating evaporation:

[0051] The evaporator is equipped with scrapers and a heater installed on the wall of the evaporator. It also features temperature detection and automatic adjustment instruments. After the filter residue enters the evaporator, the heater indirectly heats the evaporator wall in a nitrogen atmosphere. At 400-500°C, this effectively sublimates elemental sulfur from the filter residue. Simultaneously, the sulfur vapor is discharged from the upper end of the evaporator and enters the cooling and separation device. The remaining residue is discharged from the slag hopper at the lower end of the evaporator into the waste spiral.

[0052] Furthermore, a level meter is provided in the slag discharge hopper at the lower part of the evaporator, and the waste screw is controlled by the level meter to ensure that there is a certain level in the slag discharge hopper, so as to avoid air entering the evaporator through the waste screw after complete emptying, resulting in sulfur combustion.

[0053] The cooling medium of the liquid sulfur cooling separator is hot water. Therefore, the temperature inside the hot water cooling separator is controlled at 120-160°C, so that the gaseous sulfur vapor will neither solidify nor be too hot to be condensed and separated.

[0054] The liquid sulfur cooling separator has a liquid sulfur tank at the bottom, a liquid level gauge and a delivery pump, so that the liquid sulfur separated by cooling can be collected, delivered and recycled.

[0055] Exhaust gas scrubbing:

[0056] The exhaust gas separated by the liquid sulfur cooling separator is scrubbed in a venturi scrubber before being discharged. The venturi, with air intake in the middle and the bottom connected to the water pool at the bottom of the scrubber, is sprayed with circulating water from a circulating scrubber pump at the top. This further separates elemental sulfur from the mixed gas exiting the liquid sulfur cooling separator. The separated mixed gas is almost entirely nitrogen, meeting emission standards, and is discharged from the top of the scrubber.

[0057] The washing circulating water outlet is divided into three parts: one part goes to the venturi, one part goes to the cooling tower for cooling, and one part goes to the filter press. In this way, the washing water can be used to wash elemental sulfur in the mixed gas and then recycled after cooling.

[0058] Example 1

[0059] The sulfur residue, containing 68% sulfur, separated by the filter in the sulfur melting section of the sulfur-based acid production process is cooled and conveyed via a feed belt to a crusher, producing fine-grained sulfur-melting filter residue. The filter residue enters a feeder hopper, where it is metered and fed into an evaporator. An electric heater mounted on the evaporator wall indirectly heats the residue. Simultaneously, nitrogen is introduced through a dedicated nitrogen pipeline at the front of the evaporator. The electric heater, controlled by an automatic temperature control instrument, heats the residue to 400-500°C. The sulfur in the filter residue sublimates, mixes with the nitrogen, and separates from the solid residue, resulting in a sulfur-containing vapor mixture and residual solid residue. The residual solid residue is cooled in the hopper and waste spiral before exiting the evaporator. The sulfur-containing vapor mixture is conveyed via an insulated steam conveying pipeline to a liquid sulfur cooling separator, where sulfur is separated from the mixture by cooling in a hot water environment at 120-160°C. The separated sulfur flows by gravity into a liquid sulfur tank at the bottom of the liquid sulfur cooling separator and is pumped to a sulfur-melting filter press for recycling. The separated mixed gas is transported to the venturi tube through a steam insulation conveying pipeline and washed with circulating washing water. The qualified tail gas is discharged into the atmosphere through a washing tower. The granular sulfur washed by water is filtered through a filter press plate, collected and recycled to the sulfur melting section for recycling.

[0060] The above embodiments are used to explain the technical solutions of the present invention. However, the present invention is not limited to the above embodiments, which does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by those skilled in the art based on the present invention, or equivalent replacement of materials used in the present invention, etc., shall fall within the scope of protection of the patent.

Claims

1. A system for recovering sulfur from molten sulfur filter residue, the system comprising a feed belt (01), characterized in that: The discharge end of the feed belt (01) is connected to the feed port of the crusher (02). A feeder (03) is provided below the discharge port of the crusher (02). The upper portion of the feeder (03) is a hopper, which is located below the crusher (02). The discharge port of the feeder (03) is connected to the evaporator (04). A heater (05) is provided on the outside of the evaporator (04). The top of the evaporator (04) is connected to a liquid sulfur cooling separator (06), a venturi tube (11) and a washing tower (12) through a pipeline.

2. The system for recovering sulfur from molten sulfur filter residue according to claim 1, characterized in that: The evaporating kettle (04) is provided with a nitrogen pipeline (08) for introducing nitrogen into the evaporating kettle (04); the evaporating kettle (04) is provided with a material level meter for controlling the feeding so that the material in the evaporating kettle (04) is within a required range; and the slag discharge hopper at the lower end of the evaporating kettle (04) is connected to the waste spiral (07).

3. The system for recovering sulfur from molten sulfur filter residue according to claim 2, characterized in that: A water cooling spray device is provided on the outside of the waste spiral (07) cylinder to cool the waste spiral (07) including the residual slag inside.

4. The system for recovering sulfur from molten sulfur filter residue according to claim 1, characterized in that: The evaporation kettle (04) and the liquid sulfur cooling separator (06) are connected via a pipeline, and the pipeline is provided with a steam insulation jacket to prevent the sublimated sulfur from solidifying and clogging the pipeline.

5. The system for recovering sulfur from molten sulfur filter residue according to claim 1, characterized in that: The liquid sulfur cooling separator (06) is provided with a hot water pipeline (09), and a liquid sulfur tank (10) is provided at the bottom of the liquid sulfur cooling separator (06). A liquid level meter and a delivery pump are provided in the liquid sulfur tank (10).

6. The system for recovering sulfur from molten sulfur filter residue according to claim 1, characterized in that: The top of the liquid sulfur cooling separator (06) is connected to the venturi (11) through a pipeline; preferably, the top of the liquid sulfur cooling separator (06) is connected to the upper and middle part of the venturi (11) through a pipeline to receive tail gas, the bottom of the venturi (11) is connected to the bottom pool of the washing tower (12), and the top is sprayed with circulating water delivered from the circulating washing pump (13).

7. The system for recovering sulfur from molten sulfur filter residue according to claim 6, characterized in that: The washing tower (12) has a cooling tower at the top and a water pool at the bottom. The water pool is connected to the venturi (11), the cooling tower and the filter press plate (14) through a circulating washing pump (13).

8. The system for recovering sulfur from molten sulfur filter residue according to claim 5, characterized in that: The liquid sulfur tank (10) is connected to the molten sulfur filter press section via a pipeline, and the liquid sulfur separated by the liquid sulfur cooling separator (06) can be directly transported to the molten sulfur filter press section.

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