阅读说明：本技术 一种采用气化器高温区除焦油的方法 (method for removing tar by gasifier high-temperature zone ) 是由 龚佰勋 黎莉 邓晨 曹桦钊 陈洪一 于 2019-09-29 设计创作，主要内容包括：本发明公开一种采用热解气通过气化装置高温区除焦油的方法,适用于经过干燥后的垃圾,进入热解器在200℃-650℃之间发生裂解,产生的热解产物(半焦、焦油、热解气)进入专用的下吸式高温气化炉,经1100℃～1300℃的喉口氧化区高温进行裂解反应,生成甲烷、乙烷及乙烯等低碳类的可燃气体；再利用高温气体对热解反应提供能量,最后气体净化后进入后端资源化利用设备,实现能源高效利用。(The invention discloses a method for removing tar by pyrolysis gas through a high-temperature region of a gasification device, which is suitable for garbage after being dried, the garbage enters a pyrolyzer to be pyrolyzed at the temperature of between 200 and 650 ℃, the generated pyrolysis products (semi-coke, tar and pyrolysis gas) enter a special downdraft high-temperature gasification furnace, the pyrolysis reaction is carried out at the high temperature of a throat oxidation region of between 1100 and 1300 ℃ to generate combustible gas of low carbon, such as methane, ethane, ethylene and the like, the high-temperature gas is utilized to provide energy for the pyrolysis reaction, and finally the gas is purified and enters rear-end resource utilization equipment to realize the efficient utilization of energy.)

1, method for removing tar by gasifier high temperature area, which is characterized in that the method comprises the components of high temperature pyrolysis of domestic garbage, high temperature oxidation of pyrolysis product, high temperature reduction of oxidation carbon residue, tar cracking and ash carrying.

2. The high-temperature pyrolysis of household garbage according to claim 1, characterized in that: the solid waste domestic garbage absorbs heat and is subjected to high-temperature decomposition, so that preliminary reduction treatment of the garbage is realized, and the low-temperature decomposition effect is realized.

3. The high-temperature oxidation of the pyrolysis product according to claim 1, wherein: the pyrolysis product realizes the combustion and energy release of the household garbage in an oxidation layer by adjusting the oxygen amount of the gasifying agent to be 0.2-0.35 of the theoretical oxygen amount, and the decomposition of tar in a high-temperature environment is realized by maintaining the high-temperature environment of 1100-1300 ℃ in an oxidation zone.

4. The high-temperature reduction of oxidized carbon residue according to claim 1, wherein most of the tar after high temperature decomposition is completed at high temperature to generate small molecule gas, and unburned carbon residue realizes reduction reaction between carbon and carbon dioxide in the high-temperature reduction layer to generate carbon oxide.

5. The tar cracking and ash carrying method according to claim 1, wherein the pyrolysis tar is maintained at a high temperature of 1100-1300 ℃ for more than 0.3s in the high temperature environment, sufficient retention time and complete cracking of the tar are achieved, a small amount of uncracked tar is adhered to the ash, and the adhered tar is discharged out of the gasification device together with the ash , so as to achieve the carrying effect of undecomposed carbon and a small amount of tar.

Technical Field

The invention relates to methods for removing tar by adopting high temperature, in particular to methods for removing tar by adopting a high-temperature region of a gasifier, which are suitable for decomposing low-temperature pyrolysis tar.

Background

With the rapid development of social economy, the acceleration of urbanization process and the rapid improvement of the living standard of people in China, the urban domestic garbage also grows rapidly, the components of the domestic garbage in China have great difference according to the national conditions of China and the influence of factors such as residential living habits, natural environments, energy composition, economic development and the like, and the combustible part of the existing domestic garbage can be roughly divided into two categories of biomass and fossil fuels.

In the existing household garbage treatment method, the thermal treatment resource is which is the main mode for changing garbage into valuables, the garbage thermal treatment has the advantages of short period, small occupied area and the like, the garbage thermal treatment technology comprises pyrolysis and incineration, most of the garbage treatment uses a high-temperature incinerator for incineration at 850 ℃, the energy consumption is large, and a plurality of harmful substances, particularly dioxin which is a highly toxic carcinogenic pollutant, are easily generated in the incineration process.

Pyrolysis is a process of heating and decomposing organic matters in an oxygen-free or oxygen-deficient state, wherein the pyrolysis utilizes the thermal instability of the organic matters, the chemical bonds of the compounds are broken by utilizing heat energy, small molecules are generated to be gaseous, larger molecules are primary tar, coke is not decomposed completely, and the tar generated in the process has definite influence on the environment if not subjected to deep treatment to be small molecule gas.

The harm brought by the tar mainly comprises the following points:

energy is wasted, the energy of the tar product generally accounts for 5-15% of the total energy, the part of energy is difficult to be utilized with the combustible gas at low temperature, and most of the energy is wasted;

clogging, corrosion of equipment and pipes. In the gasification process, tar is condensed to form a viscous liquid substance along with the reduction of temperature, and the viscous liquid substance is attached to the inner wall of the pipeline to corrode and block the pipeline. The tar enters gas equipment and can affect the safe operation of a compressor, a gas turbine, an internal combustion engine and the like;

polluting the environment and threatening health. Many of the components in tar are highly toxic, cause environmental pollution problems, and are carcinogenic, threatening the health of personnel exposed to the gasification system.

The prior tar treatment method adopts different tar treatment methods according to the tar generation process, and is divided into a physical purification method and a chemical conversion method. Mainly comprises a spraying method, a bubbling water bath method, a dry filtering method and a proper combination of a plurality of methods.

1) Spraying method for removing tar and dust

The tar and dust in the fuel gas are removed by a spraying method. In order to improve the dust removal effect, some gasification stations fill the container with corncob filler, which can achieve the filtering effect. The corncobs should be replaced periodically, dried in the sun, added into the raw materials of the gasification furnace to be burnt, and simultaneously, the secondary pollution caused by water is prevented.

2) Bubbling water bath method for removing tar and dust

The water is added with quantitative sodium hydroxide to form dilute alkali solution, which has good effect on removing organic acid, tar and other impurities in the fuel gas.

3) Dry filtering to remove tar and dust

The dry filtering process for removing tar and dust from fuel gas includes filling crushed corn cob, wood chip, husk or charcoal grains in container to let fuel gas pass through it or passing fuel gas through ceramic filter core, and passing fuel gas through paper air filter core before it enters cylinder for engine.

The above methods can produce secondary water pollution and secondary pollution of filtered substances.

The tar can be cracked at high temperature and is in a gas state with the gasified gas , and the proper treatment method is adopted for the tar in the gasified gas, so that the components of the tar in the gasified gas are reduced, the quality of the gasified gas is improved, and the method is directions for solving the tar problem in the development of the high-temperature gasification technology.

Disclosure of Invention

The invention aims to provide a treatment method of household garbage pyrolysis tar, which is used for solving the problem of tar content in the conventional pyrolysis gas.

After the domestic garbage is pyrolyzed in the pyrolyzing furnace, the solid coke, combustible gas, water, liquid fuel and the like are discharged out of the furnace body, and the aim of no pollution to the atmosphere can be achieved by performing steps of separation treatment.

The specific scheme is that pretreated combustible components of the household garbage pass through a pyrolyzer, steps are carried out, energy carried in a heat medium is utilized to heat the combustible components of the household garbage, the temperature of the combustible components is raised firstly, the combustible components absorb enough energy, steps are carried out, internal organic matters begin to decompose after reaching a high-temperature state, and organic components such as solid semicoke, pyrolysis gas, tar, pyroligneous liquor and the like are formed.

, organic matters generated by pyrolysis are conveyed to a gasifier through a pipeline, part of semicoke in the gasifier is contacted with gasifying agent air, combustion reaction is carried out under the condition that the temperature is higher than the ignition temperature, step is carried out, a large amount of heat is generated by combustion, the heat is roughly divided into four parts, wherein part of high-temperature heat is used for maintaining the high temperature of a high-temperature throat section in the gasifier at about 1200 ℃, part of high-temperature heat is used for molecular bonds of macromolecular organic matters in tar to absorb energy and break and decompose into micromolecular gas, part of higher heat is used for carbon in unburned semicoke to react with carbon dioxide to generate carbon oxide combustible gas, and part of high-temperature gas after temperature reduction is carried out of the gasifier body.

, most of the tar is decomposed during the decomposition process of the tar, a small amount of undecomposed tar, part is adhered to ash and discharged out of the gasifier through the grate, and the minimum part is discharged with the crude gas.

And , purifying the discharged crude fuel gas by a rear-end gas purification process, and performing resource treatment in an internal combustion power generation system.

Drawings

FIG. 1 is a diagram of a pyrolysis system of kinds of tar according to the present invention.

FIG. 1 shows, according to the drawing: 1. the pyrolysis device 2, the central pipe section structure 3, the slag discharging device 4 and the gas purification system.

FIG. 2 is a diagram of the pyrolysis mechanism of kinds of tar according to the present invention.

Detailed Description

The invention also provides an household garbage low-temperature pyrolysis treatment method, and the household garbage pyrolysis treatment system comprises the following steps.

Adding the household garbage into a pyrolysis furnace, and pyrolyzing the household garbage by means of heat carried by a jacket of hot fluid additionally added in the pyrolysis furnace; the garbage enters the pyrolysis furnace, and is gradually pushed to the high-temperature end of the pyrolyzer from the cold end of the pyrolyzer through the spiral pushing device, and the temperature in the main pyrolysis furnace is also increased to the range of 650 ℃ from 200 ℃.

In the temperature rising process, chemical bonds in the internal organic matters are gradually broken and decomposed, the macromolecular organic matters are decomposed into a medium molecular structure, the medium molecular structure is decomposed into a small molecular structure, and the small molecular structure is changed into a micro molecular structure. Organic matters in the garbage are decomposed into micromolecular organic gas, macromolecular organic liquid substances (containing tar) and organic solid substances which are not decomposed or not completely decomposed after pyrolysis.

The pyrolysis product enters a gasifier, the semicoke and oxygen in a gasifying agent interact to generate oxidation reaction at a high-temperature throat section, a large amount of heat is released when carbon dioxide is generated, the oxygen amount of the gasifying agent is adjusted to be 0.2-0.35 of the theoretical oxygen amount, the temperature of a gasification layer of the gasifier is guaranteed to fluctuate within the high-temperature range of 1100-1300 ℃, tar is cracked to generate combustible gas after being more than 0.2s in an oxidation layer, part of tar is tar which is not decomposed in time and is adhered to the surface of slag to perform reduction reaction, and is finally discharged out of the gasifier together with residue , a small amount of tar is treated at the rear end to reach or be higher than the national standard for discharge, in the process, solid residue is discharged out of the gasifier along with the slag, and the generated combustible gas is discharged out of the gasifier through.

The invention has the beneficial effects that:

, cracking tar at high temperature to generate small molecule gas, wherein the energy is transferred to the small molecule gas, so that the energy is utilized, the energy utilization rate is improved, and the pollution of tar to the environment is reduced;

according to the invention, tar is subjected to pyrolysis, so that the generation of tar is reduced, and the instability of equipment operation is reduced.