CN111977993A - A device and method for desulfurization or ashization in the production of soda ash by returning stone and sand to pulp - Google Patents

Abstract

The invention relates to a device and a method for desulfurizing or ash-forming in the production of soda ash by returning rock and sand to pulp. The sand machine separates the emulsion and the solid fine sand, the emulsion is sent to the power plant for desulfurization, and the solid fine sand is pulverized and then enters the ash machine for ash; In the process of ash removal, it not only greatly improves the ash concentration, but also reduces the consumption of raw materials in the production of soda ash. The implementation of the combined production process of sand-returning and pulping of the present invention reduces the production cost of soda ash production enterprises and thermal power companies, and at the same time adapts to the current environmental protection situation and the needs of enterprise development, and provides favorable guarantees for enterprises to take a sustainable development path.

Description

A device for desulfurization or ashization in the production of soda ash by returning stone and sand to pulp and the same method

technical field

The invention relates to the comprehensive utilization of solid wastes produced in the industry of soda ash production by the ammonia-alkali method, in particular to a device and method for desulfurization or ashization of returning rock and sand to pulp in soda ash production.

Background technique

Soda ash is a basic industrial raw material with the largest output and a wide range of uses in the basic chemical industry. At present, my country is the world's largest producer of soda ash, and the only soda ash producer in the world with three mature production processes of combined caustic soda, ammonia caustic soda and trona. Among the soda ash production enterprises in my country, it is mainly the production process of soda ash produced by the ammonia-alkali method. However, in the prior art, when soda ash is produced by the ammonia-alkali method, three kinds of solid wastes are inevitably generated in the limestone calcination process: returning sand, returning stone and crushed stone. With the increase of environmental protection efforts, the three kinds of solid wastes produced by the limestone calcination process will seriously restrict the sustainable development of enterprises, and are also the bottleneck restricting the development of enterprises at present.

In the patent "A method of manufacturing desulfurizer from solid waste generated in the industry of soda ash factory" (Patent Application No.: 201310121724.7), it is proposed to mix the returned stone, sand and crushed stone evenly, then grind and select the powder through a ball mill and enter the finished product warehouse. This process converts the solid three wastes into high-quality limestone powder desulfurizer, but there are serious deficiencies in this process, which are mainly manifested in: First, based on the calculation of an annual output of 1.2 million tons of soda ash, the daily production of returned stone, sand, sand, etc. The output of crushed stone reaches about 1,000 tons, and it is difficult to achieve the processing capacity of 1,000 tons of grinding and desulfurization per day; secondly, due to the physical and chemical properties of returning stone and sand, the material is pulverized, which has caused serious environmental sanitation on the production site. Third, the waste generated after grinding and desulfurization fails to meet the requirements of zero pollution and zero discharge; fourth, due to the physical and chemical properties of returning stone and sand, the materials are pulverized, and in the desulfurization process of the power plant It caused serious blockage to the pipeline and equipment, making the equipment unable to operate normally.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, the present invention proposes a method of wet grinding of the returned stone and sand with a particle size of less than 40 mm produced by the limestone calcination process, and then the emulsion and solid fine sand are separated out through a spiral sand washer, and the emulsion is sent to the It enters the power plant for desulfurization, and the solid fine sand enters the ash machine for ash after pulverization; secondly, the present invention can directly send the ground slurry into the ash process, which not only avoids the return of sand due to the shutdown of the power plant No place to go has a serious impact on the environment, and it can also greatly improve the concentration of ash and reduce the consumption of raw materials in the production of soda ash. The implementation of the combined production process of sand-returning and pulping of the present invention reduces the production cost of soda ash production enterprises and thermal power companies, provides favorable measures for soda ash in the treatment of solid waste sand, and also adapts to the current environmental protection situation and the needs of enterprise development. Taking the road of sustainable development provides favorable guarantees.

First of all, a device for desulfurizing or ash-returning the limestone and sand-returning slurry produced by the limestone calcination process in the soda ash production of the present invention is provided, which comprises a sand-returning bin for storing the returned-stone and sand-returning silo; The material outlet of the sand silo is connected to the material inlet of the ball mill through the feeding pipe, and the slurry outlet of the ball mill is connected to the buffer barrel for temporarily storing the slurry through the pipeline. The slurry output pipeline of the buffer barrel is divided into the first and second branch pipes. The first branch pipe is connected to the material inlet of the spiral sand washer through the first slurry pump, the solid fine sand outlet of the spiral sand washer is connected to the ash machine through the material conveying device, and the emulsion outlet of the spiral sand washer is connected through the conveying pipeline It is connected to the desulfurization device of the power plant, and the second branch pipe is connected to the ash machine after passing through the second slurry pump.

Further, after the first slurry pump, the first branch pipe branches out into a third branch pipe and is connected to the liquid feed port of the sand return bin, and/or, the second branch pipe branches into a fourth branch pipe after the second slurry pump and is connected to the sand return tank. The liquid feed port of the silo.

Further, the washing water inlet of the buffer bucket is connected with the washing water input pipeline, the washing water input pipeline is provided with a washing water pump for pressurization, and the washing water input pipeline between the washing water pump and the buffer bucket is provided for controlling the entry of the washing water. Buffer barrel valve.

Further, the first branch pipe is provided with a first pneumatic regulating valve.

Further, a branch pipe branched from the washing water input pipeline between the washing water pump and the valve for controlling the entry of the washing water into the buffer barrel is connected to the washing water inlet of the sand returning bin through the second pneumatic regulating valve.

The returning stone and returning sand described in this application refer to the fact that in the production of soda ash, limestone is calcined to generate lime, and then reacts with water (referred to as ash in the industry) to generate calcium hydroxide emulsion (referred to as milk of lime in the industry), while Some limestones are not completely calcined to be ash in the form of limestone. After the ash process, the stones that are still large in size are called returning stones, and those with small particles (such as sand) are called returning sand.

The present invention further relates to a method for pulping and desulfurization or ash for returning rock and sand, the method comprising:

(1) After sieving the returned stone and sand (for example, using a rotary sieve for returning stone), the large returned stone (with a particle size greater than 40mm) is sent to the lime kiln for secondary calcination, and the small particle returned stone (with a particle size of 10- 40mm) and return sand (the particle size is usually below 10mm) into the sand return bin,

(2) In step (1), the mixed material of returning stone and returning sand in the sand returning silo is driven by washing water (the flow rate of the mixed material entering the ball mill can be 7-11t/h (calculated with an annual output of 600,000 tons of soda ash enterprise) ), the washing water flow rate can be 20-25m ³ /h) into the ball mill through the feed pipe, and the slurry obtained after being ground by the ball mill (usually reaching a particle size range of 12-286 μm) (the solid-liquid ratio in the slurry is 15-23%, The concentration of CaO in the slurry is kept at 15-35tt) and transported to the buffer barrel,

(3) In step (2), the slurry in the buffer tank is pumped to the spiral sand washer, the emulsion in the slurry is separated from the solid fine sand by the spiral sand washer, and the emulsion slurry is sent to the power plant for desulfurization, and the solid fine sand is separated. The sand is sent to the factory's ashes process for ashes; and/or

In step (2), the slurry in the buffer barrel is directly pumped to the ash machine for secondary ash.

In the case that the power plant does not need or needs less than the output of the method of the present invention, the slurry in the buffer barrel in step (2) is directly pumped to the ash machine for secondary ash, or partially desulfurized ash, and partially directly ash, When both are carried out at the same time, the ratio of the part where desulfurized ash is carried out and the part where ash is directly melted can be set as required.

This process can use a Φ1830*7000 double-silo wet ball mill with a maximum speed of 24.3r/min, a production capacity of 7.8-13.8t/h, and an effective volume of 16m ³ . This equipment adopts the frequency conversion operation of the high-voltage motor, and the speed of the equipment can be changed by adjusting the frequency, so as to avoid the impact of the steel balls in the ball mill on the cylinder of the equipment after the material is reduced, and improve the service life of the equipment.

Considering that the solid fine sand particles in the slurry are small, a spiral sand washing machine with a spiral diameter of 500mm, a processing capacity (calculated according to the amount of solid fine sand) of 4-9t/h and a spiral speed of 8-12.5r/min can be used.

After the separated emulsion is sent to the power plant, if the power plant is overused or shut down, the ball mill can directly grind the slurry from the buffer barrel and send it directly to the ash machine for secondary ash, avoiding the shutdown of the power plant. As a result, the returned sand has nowhere to go, which has a serious impact on the environment. It can also effectively increase the ash temperature in the ash process by 2-5°C, and the ash milk concentration by 3-5tt. At the same time, each ton of soda ash can save 50 kilograms of limestone.

Further, the slurry part in the buffer barrel (usually accounting for 30-50wt% of the total slurry of the ball mill) is transported to the sand return bin, and the slurry enters the ball mill for grinding for the second time. It can effectively avoid damage to the liner of the ball mill when the feed amount of the ball mill becomes smaller (for example, lower than the conventional feed amount).

Further, in step (2), when the solid-to-liquid ratio of the slurry entering the buffer barrel is too high (for example, the solid-to-liquid ratio in the slurry is greater than 23%), the washing water is transported to the buffer barrel through the washing water input pipeline for diluting the slurry. The solid-liquid ratio (to the solid-liquid ratio is reduced to 15-23%), to avoid the blockage of the pipeline due to transportation.

In step (2), the washing water is sent into the sand returning bin, and the washing water drives the mixed material to enter the ball mill through the feeding pipe (preferably the flow pipe), so as to avoid the sand returning and pulverization caused by the long-term shutdown of the ball mill and blocking the sand returning. Second, the use of feed flow pipe feeding can effectively improve the production environment on site.

In step (2), washing water is connected to the top of the buffer barrel, which is used to flush the entire slurry conveying pipeline with the washing water when the ball mill stops running, and then enter the production water system of the whole plant after centralized precipitation, so as to avoid the pipeline being stopped for a long time. Until the slurry in the pipeline is pulverized and the pipeline is blocked.

Beneficial effects of the present invention:

(1) Through the implementation of the process of the present invention, the sand returning in the production of soda ash can be effectively controlled, and the environmental pollution caused by pulverization can be achieved.

(2) Through the implementation of the process of the present invention, the desulfurization efficiency of the power plant can reach more than 99%, which not only reduces the production cost of the power plant, but also provides a guarantee for the realization of zero emission of the enterprise.

(3) The slurry in the process of the present invention is directly fed into the ash machine, which can effectively increase the ash temperature in the ash process by 2-5 degrees, and the ash milk concentration by 3-5tt concentration, and at the same time, every ton of soda ash can save limestone 50 kilogram. It can also solve the serious pollution to the environment caused by the accumulation of sand returning due to the shutdown of the power plant.

(4) The technology of the present invention is combined with the new technology of salt-alkali-calcium co-production, so that it is the first time in the soda ash industry that measures to realize zero discharge and zero pollution of returning sand are pioneered, which provides a backing for the sustainable development of the enterprise.

Description of drawings

Fig. 1 is a schematic diagram of a device for desulfurization or ashization in the production of soda ash according to the present invention.

Reference number:

Sand return bin 1, ball mill 2, feed flow pipe 3, buffer barrel 4, first slurry pump 5, second slurry pump 6, first pneumatic control valve 7, second pneumatic control valve 8, valve 9, spiral sand washing machine 10,

The slurry output pipe L, the first branch pipe L1, the second branch pipe L2, the third branch pipe L3, the fourth branch pipe L4, the washing water input pipe L5, and the fifth branch pipe L6.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, in a kind of soda ash production of the present invention, the desulfurization or ash-returning device is carried out by returning the stone and sand to the slurry, which comprises a sand returning bin 1 for storing the returning stone and sand, and the sand returning bin 1 The material outlet of the ball mill 2 is connected to the material inlet of the ball mill 2 through the feed flow pipe 3, and the slurry outlet of the ball mill 2 is connected to the buffer barrel 4 for temporarily storing the slurry through the pipeline. The slurry output pipeline L of the buffer barrel 4 is divided into the first and second Two or two branch pipes (L1, L2), the first branch pipe L1 is connected to the material inlet of the spiral sand washer 10 through the first slurry pump 5, and the solid fine sand outlet of the spiral sand washer 10 passes through the material conveying device and the ash machine. Connection, the emulsion outlet of the spiral sand washing machine 10 is connected to the desulfurization device of the power plant through the slurry conveying pipeline, the first branch pipe L1 is divided into the third branch pipe L3 after passing through the first slurry pump 5, and the second branch pipe L2 is passed through the second slurry. The pump 6 is then connected to the ashes machine. The second branch pipe L2 passes through the second slurry pump 6 and branches into a fourth branch pipe L4.

The washing water inlet of the buffer bucket 4 is connected with the washing water input pipeline L5, the washing water input pipeline is provided with a washing water pump (not shown) for pressurization, and the washing water input pipeline between the washing water pump and the buffer bucket is provided with a washing water pump for pressurization. Control the valve 9 of the wash water entering the buffer tank.

The first branch pipe L1 is provided with a first pneumatic regulating valve 7 .

A fifth branch pipe L6 branched from the washing water input pipeline between the washing water pump and the valve 9 is connected to the washing water inlet of the sand returning bin 1 after passing through the second pneumatic regulating valve 8 .

Example 1

A method for desulfurization or ashization of returning stone and sand-returning pulping in soda ash production, the method comprising:

(1) After 12-16t/h (calculated based on an annual output of 600,000 tons of soda ash), the returned stone and sand are screened with a return stone rotary screen, and the large returned stone with a particle size larger than 40mm is sent to the second lime kiln After the second calcination, the mixture of small particles with a particle size of less than 40mm returned to the sand and the mixture of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) is screened into the sand return bin,

(2) Close the valve on the washing water input pipeline, open the second pneumatic control valve, and input the washing water to the sand returning bin at a flow rate of 20-25 m ³ /h. The mixed material is driven by washing water at a speed of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) and enters the ball mill through the feed flow pipe. The slurry with 15-23% and CaO concentration of 15-35tt is transported to the buffer barrel,

(3) In step (2), the slurry in the buffer tank will be pressurized by the first slurry pump, and then transported to the spiral sand washer through the first branch pipe. The spiral sand washer separates the emulsion and the solid fine sand, and the The liquid is sent to the power plant for desulfurization, so that the sulfur dioxide content in the power plant flue gas can be reduced to less than 8mg/ ^m3 (the national standard is within 100mg/ ^m3 ), and the solid fine sand is sent to the ashes machine for ashes.

When the feeding amount of the ball mill becomes smaller (for example, lower than the conventional feeding amount), part of the slurry in the buffer barrel is transported to the sand return bin, and the slurry enters the ball mill for the second time for grinding. It is used to connect the washing water above the buffer barrel when the ball mill stops running, and use the washing water to flush the pipeline, so as to avoid the pipeline blockage caused by the slurry powder in the pipeline caused by the long-term stop of the pipeline.

Example 2

A method for ash-returning stone and sand-returning pulping in soda ash production, the method comprising:

(1) After 12-16t/h (calculated based on an annual output of 600,000 tons of soda ash), the returned stone and sand are screened with a return stone rotary screen, and the large returned stone with a particle size larger than 40mm is sent to the second lime kiln After the second calcination, the mixture of small particles with a particle size of less than 40mm returned to the sand and the mixture of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) is screened into the sand return bin,

(2) Close the valve on the washing water input pipeline, open the second pneumatic control valve, and input the washing water to the sand returning bin at a flow rate of 20-25 m ³ /h. The mixed material is driven by washing water at a speed of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) and enters the ball mill through the feed flow pipe. The slurry with 15-23% and CaO concentration of 15-35tt is transported to the buffer barrel,

(3) In step (2), the slurry in the buffer barrel is pressurized by the second slurry pump and transported to the ash machine for secondary ash, which avoids the return of sand due to the shutdown of the power plant and has no place to return, and causes serious environmental damage. influences. It can also effectively increase the ash temperature by 2-5°C, the ash milk concentration by 3-5tt, and save 50Kg of limestone per ton of soda ash.

Example 3

A method for desulfurization or ashization of returning stone and sand-returning pulping in soda ash production, the method comprising:

(1) After 12-16t/h (calculated based on an annual output of 600,000 tons of soda ash), the returned stone and sand are screened with a return stone rotary screen, and the large returned stone with a particle size larger than 40mm is sent to the second lime kiln After the second calcination, the mixture of small particles with a particle size of less than 40mm returned to the sand and the mixture of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) is screened into the sand return bin,

(2) Close the valve on the washing water input pipeline, open the second pneumatic control valve, and input the washing water to the sand returning bin at a flow rate of 20-25 m ³ /h. The mixed material is driven by washing water at a speed of 7-11t/h (calculated based on an annual output of 600,000 tons of soda ash) and enters the ball mill through the feed flow pipe. The slurry with 15-23% and CaO concentration of 15-35tt is transported to the buffer barrel,

(3) In step (2), the slurry part in the buffer barrel is pressurized by the first slurry pump, and then transported to the spiral sand washer through the first branch pipe, and the spiral sand washer separates the emulsion and the solid fine sand, and the turbidity The liquid is sent to the power plant for desulfurization, so that the sulfur dioxide content in the flue gas of the power plant can be reduced to below 8mg/ ^m3 (the national standard is within 100mg/ ^m3 ), and the solid fine sand is sent to the ashes machine for ashes,

(4) In step (2), the remaining part of the slurry in the buffer barrel is pressurized by the second slurry pump and transported to the ash machine for secondary ash, which can avoid the situation of excess capacity of the ball mill due to the reduction of the desulfurization amount in the power plant. It is helpful to increase the ash temperature and ash milk concentration, and at the same time reduce the consumption of soda ash production.

Example 4

(1) After the 16-20t/h (calculated based on the annual output of 600,000 tons of soda ash enterprise, and in the case of lime burning) returned stone and sand returned to the screen, the large blocks with a particle size greater than 40mm were screened with a return stone rotary screen. The returned stone is sent to the lime kiln for secondary calcination, and the mixture of small particle returned stone and returned sand with a particle size of less than 40mm is 10-13t/h (calculated based on an annual output of 600,000 tons of soda ash) and is screened into the sand return bin.

(2) Close the valve on the washing water input pipeline, open the second pneumatic control valve, and input the washing water to the sand returning bin at a flow rate of 20-25 m ³ /h. The mixed material enters the ball mill at the speed of 10-13t/h (calculated based on the annual output of 600,000 tons of soda ash enterprise) driven by the washing water through the feed flow pipe, and the solid-liquid obtained after being ground by the ball mill (to the particle size range of 12-286μm) The slurry with a ratio greater than 23% and a CaO concentration of 15-35tt is transported to the buffer barrel, and the washing water is transported to the buffer barrel through the washing water input pipeline to dilute the slurry to reduce the solid-liquid ratio to 15-23%.

(3) In step (2), the slurry in the buffer tank will be pressurized by the first slurry pump, and then transported to the spiral sand washer through the first branch pipe. The spiral sand washer separates the emulsion and the solid fine sand, and the The liquid is sent to the power plant for desulfurization, and the solid fine sand is sent to the ashes machine for ashes.

Claims (9)

1. The utility model provides a will return stone in the soda production, return sand slurrying carries out the device of desulfurization or change ash, a serial communication port, it includes that one is used for storing and returns stone, the sand return storehouse of returning sand, the material export in sand return storehouse is connected in the material import of ball mill through the inlet pipe, the thick liquid export of ball mill is connected with the buffer bucket that is used for keeping in the thick liquid through the pipeline, the thick liquid output pipeline of buffer bucket divide into first, two branch pipes of second, first branch pipe is connected in spiral sand washer's material import behind first thick liquid pump, spiral sand washer's solid fine sand export is connected with the ash melting machine through material conveyor, spiral sand washer's emulsion export is connected with the desulphurization unit of power plant through thick liquid conveying pipeline, the second branch pipe is connected in the ash melting machine behind second thick liquid pump.

2. The apparatus according to claim 1, characterized in that the first branch is connected to the liquid feed opening of the sand return silo after the first slurry pump and/or the second branch is connected to the liquid feed opening of the sand return silo after the second slurry pump and the fourth branch.

3. The device according to claim 1 or 2, wherein the first branch pipe is provided with a first pneumatic regulating valve.

4. The device according to any one of claims 1 to 3, wherein the washing water inlet of the buffer barrel is connected with a washing water input pipeline, a washing water pump for pressurizing is arranged on the washing water input pipeline, and a valve for controlling the washing water to enter the buffer barrel is arranged on the washing water input pipeline between the washing water pump and the buffer barrel.

5. The apparatus as claimed in claim 4, wherein a branch pipe branched from the washing water input pipe between the washing water pump and the valve for controlling the washing water to enter the buffer tank is connected to the washing water inlet of the sand return bin through the second pneumatic control valve.

6. A method of slurrying and desulfurizing or ashing return rock, return sand, the method comprising:

(1) sieving the returned stone and the returned sand, feeding the large returned stone (with the granularity of more than 40mm for example) into a lime kiln for secondary calcination, feeding the mixture of the small-particle returned stone (with the granularity of 10-40mm for example) and the returned sand into a sand return bin,

(2) in the step (1), the mixed material of the return stone and the return sand in the return sand bin enters the ball mill through the feeding pipe under the driving of washing water, slurry obtained after grinding by the ball mill is conveyed to the buffer barrel,

(3) pumping the slurry in the buffer barrel in the step (2) to a spiral sand washer, separating emulsion and solid fine sand by the spiral sand washer, feeding the emulsion to a power plant for desulfurization, and feeding the solid fine sand to an ash melting machine for ash melting; and/or

And (3) directly pumping the slurry in the buffer barrel in the step (2) to an ash melting machine for secondary ash melting.

7. A method according to claim 6, characterized in that when the feeding amount of the ball mill is reduced (for example, lower than the conventional feeding amount), the slurry in the buffer barrel is partially conveyed to the sand return bin, and the slurry enters the ball mill for grinding twice.

8. The method of claim 6, wherein in the step (2), when the concentration of the slurry entering the buffer barrel is too high (for example, the solid-to-liquid ratio in the slurry is more than 23%), the washing water is conveyed to the buffer barrel through the washing water input pipeline for diluting the slurry (until the solid-to-liquid ratio is reduced to 15-23%), and the pipeline is prevented from being blocked due to conveying.

9. The method according to claim 6, wherein in the step (2), washing water is introduced above the buffering barrel for flushing the pipeline with the washing water when the ball mill stops operating.

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