阅读说明：本技术 一种用两段式热解技术处理废盐的系统及方法 (System and method for treating waste salt by using two-stage pyrolysis technology ) 是由 郑先强 毛威 张业岭 梁玉辉 刘思慧 刘倩倩 聂超 刘沐之 于 2021-07-07 设计创作，主要内容包括：本发明涉及一种用两段式热解技术处理废盐的系统,包括一级破碎机、输送机、一段热解炉、二级破碎机、二段热解炉、废盐回收装置、一段热风炉、二段热风炉及废气处理装置；还涉及一种用两段式热解技术处理废盐的方法,步骤为：用破碎机将废盐破碎成均匀颗粒；将废盐颗粒输送至两段式热解炉进行热解处理；收集热解后的废盐并处理热解产生的废气。本发明工艺简单、运行成本低、可防止废盐结块、设备运转率高,具有明显的经济效益和环保效益。(The invention relates to a system for treating waste salt by using a two-stage pyrolysis technology, which comprises a primary crusher, a conveyor, a primary pyrolysis furnace, a secondary crusher, a secondary pyrolysis furnace, a waste salt recovery device, a primary hot blast furnace, a secondary hot blast furnace and a waste gas treatment device, wherein the primary crusher is arranged on the conveyor; also relates to a method for treating waste salt by using a two-stage pyrolysis technology, which comprises the following steps: crushing the waste salt into uniform particles by a crusher; conveying the waste salt particles to a two-section type pyrolysis furnace for pyrolysis treatment; and collecting waste salt after pyrolysis and treating waste gas generated by pyrolysis. The method has the advantages of simple process, low operation cost, capability of preventing waste salt from caking, high equipment operation rate and obvious economic benefit and environmental protection benefit.)

1. The utility model provides a system for handle waste salt with two segmentation pyrolysis technologies which characterized in that: including one-level breaker, conveyer, one section pyrolysis oven, second grade breaker, two-stage process pyrolysis oven, waste salt recovery unit, one section hot-blast furnace, two-stage process hot-blast furnace and exhaust treatment device the discharge gate department of one-level breaker connects one section pyrolysis oven through the conveyer, the exit linkage second grade breaker of one section pyrolysis oven, the exit linkage two-stage process pyrolysis oven of second grade breaker, the exit linkage waste salt recovery unit of two-stage process pyrolysis oven is connected with one section hot-blast furnace and two-stage process hot-blast furnace on one section pyrolysis oven and two-stage process pyrolysis oven respectively, and the exhaust outlet on one section pyrolysis oven and the two-stage process pyrolysis oven all is connected with exhaust treatment device.

2. The system of claim 1, wherein the two-stage pyrolysis technique comprises: the first-stage pyrolysis furnace adopts a concurrent rotary kiln, and hot air of the first-stage hot blast stove enters from the feed end of the first-stage pyrolysis furnace; the second-stage pyrolysis furnace adopts a counter-flow rotary kiln, and hot air of the second-stage hot blast stove enters from the discharge end of the second-stage pyrolysis furnace.

3. A method for treating waste salt by using a two-stage pyrolysis technology is characterized by comprising the following steps: comprises the following steps;

crushing waste salt into uniform particles by using a primary crusher;

conveying the crushed waste salt particles into a first-stage pyrolysis furnace for pyrolysis treatment, then crushing the waste salt particles in a second-stage crusher, and performing pyrolysis treatment in a second-stage pyrolysis furnace after the second-stage crushing;

and step three, collecting waste salt after pyrolysis of the second-stage pyrolysis furnace, and treating waste gas generated by pyrolysis of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace through a waste gas treatment device.

4. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: and crushing the waste salt into uniform granular waste salt by using a primary crusher, wherein the particle size of the granular waste salt is less than 30 mm.

5. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: the first-stage pyrolysis furnace and the second-stage pyrolysis furnace are respectively used as heat sources for waste salt pyrolysis through the first-stage hot blast stove and the second-stage hot blast stove, the internal temperature of the first-stage pyrolysis furnace and the internal temperature of the second-stage pyrolysis furnace are controlled by adjusting the natural gas flow of the hot blast stoves, and the internal atmosphere of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace is controlled by adjusting the air-fuel ratio.

6. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: the first-stage pyrolysis furnace and the second-stage pyrolysis furnace both adopt internal heating type rotary kilns, and a crusher is arranged between the two rotary kilns to crush salt blocks generated by low-temperature pyrolysis.

7. The method of claim 5, wherein the two-stage pyrolysis is used for treating waste salt, and the method comprises the following steps: the first-stage pyrolysis furnace adopts a concurrent rotary kiln, and hot air of the first-stage hot blast stove enters from the feed end of the first-stage pyrolysis furnace; the second-stage pyrolysis furnace adopts a counter-flow rotary kiln, and hot air of the second-stage hot blast stove enters from the discharge end of the second-stage pyrolysis furnace.

8. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: the temperature of the first-stage pyrolysis furnace is controlled to be 200-300 ℃, and the oxygen content is controlled to be below 3%; the temperature of the two-stage pyrolysis furnace is controlled to be about 500 ℃, and the oxygen content is controlled to be 6-9%.

9. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: and step four, dissolving the waste salt collected in the step three, removing impurities, evaporating and crystallizing to obtain the product salt.

10. A method according to claim 3, characterized in that it consists in treating the waste salts by a two-stage pyrolysis technique, characterized in that: the waste gas treatment device comprises a secondary combustion chamber, a waste heat recovery device and a dust and acid removal device which are sequentially connected.

Technical Field

The invention belongs to the technical field of waste salt pyrolysis treatment, and particularly relates to a system and a method for treating waste salt by using a two-stage pyrolysis technology.

Background

The industrial waste salt is mainly generated in industrial production processes of pesticide intermediates, drug synthesis, printing and dyeing and the like, and processes of solid-liquid separation, solution concentration and crystallization, sewage treatment and the like, and has the characteristics of various types, complex components, numerous sources, high treatment cost, great environmental hazard and the like. The national records of dangerous wastes list the wastes of distillation and reaction residues, waste mother liquor, reaction tank and container cleaning waste liquor, etc. in various production processes.

In recent years, the production of waste salt in China is increasing continuously, and the annual production is estimated to exceed 500 million tons, wherein the pesticide accounts for 30 percent, the fine chemical industry accounts for 15 percent, the medicine accounts for 10 percent, and the others account for 45 percent. At present, waste salt is generally treated by means of centralized temporary storage of enterprise warehouses, but how to carry out thorough harmless recycling treatment and disposal becomes a practical problem to be solved urgently, and the method is widely concerned in various social circles.

At present, the domestic resource utilization of industrial waste salt has three treatment methods, namely a salt washing method, an alkali making method and a high-temperature treatment method. Among them, the high-temperature treatment method is the most effective method capable of completely decomposing harmful substances in the waste salt, and the rotary kiln is a widely used apparatus for the treatment of the waste salt.

However, the method of burning treatment by adopting a rotary kiln has the following defects:

1. the dioxin substances are easy to generate by burning treatment in the oxidizing atmosphere;

2. the waste salt is agglomerated to cause that the organic matters wrapped in the waste salt cannot be completely decomposed;

3. the high incineration temperature leads to the waste salt in the kiln to be melted and formed into a ring, and the continuous operation cannot be realized.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a system and a method for treating waste salt by using a two-stage pyrolysis technology, which can completely decompose organic matters in the waste salt, reduce the possibility of generating dioxin substances and ensure the continuous operation of the system.

The technical problem to be solved by the invention is realized by the following technical scheme:

the utility model provides a system for handle waste salt with two segmentation pyrolysis technologies which characterized in that: including one-level breaker, conveyer, one section pyrolysis oven, second grade breaker, two-stage process pyrolysis oven, waste salt recovery unit, hot-blast furnace and exhaust treatment device one section pyrolysis oven is connected through the conveyer in the discharge gate department of one-level breaker, the exit linkage second grade breaker of one section pyrolysis oven, the exit linkage two-stage process pyrolysis oven of second grade breaker, the exit linkage waste salt recovery unit of two-stage process pyrolysis oven all is connected with the hot-blast furnace on one section pyrolysis oven and two-stage process pyrolysis oven, and the exhaust outlet on one section pyrolysis oven and the two-stage process pyrolysis oven all is connected with exhaust treatment device.

As a further improvement of the invention, the first-stage pyrolysis furnace adopts a concurrent rotary kiln, and hot air of the first-stage hot blast stove enters from the feed end of the first-stage pyrolysis furnace; the second-stage pyrolysis furnace adopts a counter-flow rotary kiln, and hot air of the second-stage hot blast stove enters from the discharge end of the second-stage pyrolysis furnace.

A method for treating waste salt by using a two-stage pyrolysis technology is characterized by comprising the following steps: comprises the following steps;

crushing waste salt into uniform particles by using a primary crusher;

conveying the crushed waste salt particles into a first-stage pyrolysis furnace for pyrolysis treatment, then crushing the waste salt particles in a second-stage crusher, and performing pyrolysis treatment in a second-stage pyrolysis furnace after the second-stage crushing;

and step three, collecting waste salt after pyrolysis of the second-stage pyrolysis furnace, and treating waste gas generated by pyrolysis of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace through a waste gas treatment device.

As a further improvement of the invention, the primary crusher is used for crushing the waste salt into uniform granular waste salt, and the particle size of the granular waste salt is less than 30 mm.

As a further improvement of the invention, the first-stage pyrolysis furnace and the second-stage pyrolysis furnace both use hot blast stoves as heat sources for waste salt pyrolysis, the internal temperature of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace is controlled by adjusting the natural gas flow of each hot blast stove, and the internal atmosphere of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace is controlled by adjusting the air-fuel ratio.

As a further improvement of the invention, the first-stage pyrolysis furnace and the second-stage pyrolysis furnace both adopt internal heating type rotary kilns, and a crusher is arranged between the two rotary kilns to crush salt blocks generated by low-temperature pyrolysis.

As a further improvement of the invention, the first-stage pyrolysis furnace adopts a concurrent rotary kiln, and hot air of the first-stage hot blast stove enters from the feed end of the first-stage pyrolysis furnace; the second-stage pyrolysis furnace adopts a counter-flow rotary kiln, and hot air of the second-stage hot blast stove enters from the discharge end of the second-stage pyrolysis furnace.

As a further improvement of the invention, the temperature of the first-stage pyrolysis furnace is controlled to be 200-300 ℃, and the oxygen content is controlled to be below 3%; the temperature of the two-stage pyrolysis furnace is controlled to be about 500 ℃, and the oxygen content is controlled to be 6-9%.

As a further improvement of the invention, the method also comprises a step four of dissolving, removing impurities and evaporating and crystallizing the waste salt collected in the step three to obtain the product salt meeting the product standard.

As a further improvement of the invention, the waste gas treatment device comprises a secondary combustion chamber, a waste heat recovery device and a dust removal and acid removal device.

The invention has the advantages and beneficial effects that:

according to the method for treating the waste salt by using the two-section pyrolysis technology, through the design of the two-section pyrolysis furnace, the pyrolysis temperature can be independently controlled according to the reaction process, namely, the temperature in the first-section pyrolysis furnace is kept at a lower temperature of 200-300 ℃, the temperature range of the maximum generation rate of dioxin can be avoided, and meanwhile, the reducing atmosphere in the furnace is kept, so that the possibility of generation of dioxin is greatly reduced; the secondary pyrolysis furnace is internally kept at a medium-temperature oxidizing atmosphere of about 500 ℃, the decomposition temperature of organic matters in the oxidizing atmosphere is reduced, the organic matters can be fully decomposed, and the temperature in the furnace is lower than the ordinary pyrolysis temperature, so that the problem that waste salt is melted and agglomerated in the furnace due to local high temperature in the furnace is avoided, and the continuous operation of the system is ensured.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

Description of the reference numerals

1-a primary crusher, 2-a conveyor, 3-a primary pyrolysis furnace, 4-a primary hot blast furnace, 5-a secondary crusher, 6-a secondary pyrolysis furnace, 7-a secondary hot blast furnace, 8-a waste salt recovery device and 9-a waste gas treatment device.

Detailed Description

The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.

Fig. 1 shows a system for treating waste salt by two-stage pyrolysis technology, which is innovative in that: including one-level breaker 1, conveyer 2, one section pyrolysis furnace 3, one section hot-blast furnace 4, second grade breaker 5, two-stage section pyrolysis furnace 6, two-stage section hot-blast furnace 7, waste salt recovery unit 8 and exhaust-gas treatment device 9 one section pyrolysis furnace is connected through the conveyer in one-level breaker's discharge gate department, the exit linkage second grade breaker of one section pyrolysis furnace, the exit linkage two-stage section pyrolysis furnace of second grade breaker, the exit linkage waste salt recovery unit of two-stage section pyrolysis furnace all is connected with the hot-blast furnace on one section pyrolysis furnace and two-stage section pyrolysis furnace, and the exhaust outlet on one section pyrolysis furnace and the two-stage section pyrolysis furnace all is connected with exhaust-gas treatment device. The first-stage pyrolysis furnace adopts a concurrent rotary kiln, and hot air of the first-stage hot blast stove enters from the feed end of the first-stage pyrolysis furnace; the second-stage pyrolysis furnace adopts a counter-flow rotary kiln, and hot air of the second-stage hot blast stove enters from the discharge end of the second-stage pyrolysis furnace.

The conveyor can be a plate chain conveyor.

A method for treating waste salt by using a two-stage pyrolysis technology is characterized by comprising the following steps: the method comprises the following steps:

crushing waste salt into uniform particles by using a primary crusher;

the primary crusher 1 is used for crushing the waste salt to make the particle size of the waste salt less than 30mm, so as to facilitate transportation and uniform thermal decomposition of organic matters therein.

Conveying the crushed waste salt particles into a first-stage pyrolysis furnace for pyrolysis treatment, then crushing the waste salt particles in a second-stage crusher, and performing pyrolysis treatment in a second-stage pyrolysis furnace after the second-stage crushing;

the crushed waste salt is conveyed to a kiln head feed inlet of a first section of pyrolysis furnace 3 through a conveyor 2, the first section of pyrolysis furnace 3 adopts a concurrent rotary kiln, a heat source is provided by a first section of hot blast stove 4, fuel of the first section of hot blast stove 4 adopts natural gas, high-temperature flue gas generated by combustion enters from the kiln head of the first section of pyrolysis furnace 3 and is in direct contact heat exchange with the waste salt, the operation temperature of the first-stage pyrolysis furnace 3 is controlled by adjusting the natural gas flow of a burner configured on the first-stage hot blast stove 4 to keep the temperature of the first-stage pyrolysis furnace at 200-300 ℃, and after the waste salt is dried and heated, wherein organic matters such as saccharides and the like begin to be decomposed and generate reducing gas, because the excess air coefficient of the natural gas burned by the first-stage hot blast stove 4 is lower, the oxygen content of the flue gas is below 3 percent, therefore, the waste salt in the first-stage pyrolysis furnace 3 is in a reducing atmosphere and the temperature of 300 ℃ at which the maximum rate of generation of dioxin is avoided.

The waste salt after drying and preliminary pyrolysis can generate part of tar and form large blocks with the salt to influence the further decomposition of organic matters, so the waste salt at the outlet of the first-stage pyrolysis furnace 3 is simply crushed by the second-stage crusher 5 and then enters the feed inlet of the second-stage pyrolysis furnace 6, the second-stage pyrolysis furnace 6 adopts a counter-flow rotary kiln, the heat source is provided by a hot blast stove 7, the fuel of the hot blast stove 7 adopts natural gas, high-temperature flue gas generated by combustion enters from the kiln tail of the second-stage pyrolysis furnace 6 and directly contacts with the waste salt for heat exchange, the running temperature of the second-stage pyrolysis furnace 6 is controlled by adjusting the natural gas flow of a combustor arranged in the second-stage hot blast stove 7 to keep the temperature at about 500 ℃, the oxygen content at the outlet of the second-stage pyrolysis furnace 6 is kept between 6% and 9% by adjusting the excess air coefficient of the natural gas combusted by the second-stage hot blast stove 7, the pyrolysis temperature of the residual organic matters in the waste salt is reduced under the aerobic condition, can complete full decomposition at a lower temperature of 500 ℃, thereby avoiding the problem of waste salt melting and caking caused by overhigh local temperature in the two-stage pyrolysis furnace 6.

And step three, collecting waste salt after pyrolysis of the second-stage pyrolysis furnace, and treating waste gas generated by pyrolysis of the first-stage pyrolysis furnace and the second-stage pyrolysis furnace through a waste gas treatment device.

The waste salt enters a waste salt recovery device 8 after being completely pyrolyzed in the two-stage pyrolyzing furnace 6, the waste salt is dissolved, insoluble substances and impurities are removed, and product salt is obtained after evaporation and crystallization in the waste salt recovery device 8, and the index of the product salt meets the industrial salt standard.

The waste gas of the export of first section pyrolysis oven 3 and second section pyrolysis oven 6 gets into exhaust treatment device 9, and waste gas passes through after-burning, retrieves flue gas waste heat, rapid cooling, dust removal, deacidification nature gas etc. in exhaust treatment device 9 in proper order, and the waste gas after the processing is up to standard to discharge to the atmosphere.

The working process of the waste salt pyrolysis system is as follows:

starting the first-stage pyrolysis furnace 3 and the second-stage pyrolysis furnace 6, and controlling the rotating speed to be 0.5-2 r/min;

starting a first-stage hot blast stove 4, a second-stage hot blast stove 7 and a waste gas treatment device 9, so that the temperature of the flue gas at the outlet of the first-stage pyrolysis furnace 3 is 200-300 ℃, the temperature of the flue gas at the outlet of the second-stage pyrolysis furnace 6 is about 500 ℃, and the interior of the first-stage pyrolysis furnace 3 and the second-stage pyrolysis furnace 6 is micro negative pressure (-50-100 Pa); starting a primary crusher 1 and a conveyor 2, adding waste salt into the primary crusher 1, controlling the particle size of the crushed waste salt to be below 30mm, feeding the crushed waste salt into a primary pyrolysis furnace 3 through the conveyor 2, and starting a secondary crusher 5;

adjusting the natural gas flow of the first-stage hot blast stove 4 and the second-stage hot blast stove 7 to ensure that the temperature of the flue gas at the outlet of the first-stage pyrolysis stove 3 and the second-stage pyrolysis stove 6 is basically kept unchanged, and adjusting the air-fuel ratio of the second-stage hot blast stove 7 to ensure that the oxygen content at the outlet of the second-stage pyrolysis stove 6 is kept between 6 and 9 percent;

the rotating speeds of the first-stage pyrolysis furnace 3 and the second-stage pyrolysis furnace 6 are adjusted to ensure that the waste salt has enough residence time in the furnaces to ensure that the organic matters in the waste salt are completely decomposed.

According to the invention, the temperature and atmosphere of the two-section type pyrolysis furnace are controlled, namely the temperature of the one-section type pyrolysis furnace is controlled to be 200-300 ℃, and the temperature in the furnace is in a reducing atmosphere, so that a temperature interval in which dioxin is easy to generate is avoided, and the possibility of generating dioxin is reduced; the temperature of the two-stage pyrolysis furnace is controlled to be about 500 ℃, the furnace is in an oxidizing atmosphere, the pyrolysis temperature of organic matters in the waste salt is reduced in the oxidizing atmosphere, and the partial high temperature in the furnace is avoided while the organic matters are fully pyrolyzed, so that the problem of molten salt caking in the furnace is solved. After the treatment by the two-stage pyrolysis technology, organic matters in the waste salt are fully pyrolyzed and carbonized, so that subsequent resource recycling is facilitated. The method has the advantages of simple process, low operation cost, capability of preventing waste salt from caking, high equipment operation rate and obvious economic benefit and environmental protection benefit.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.