CN100462315C - A Comprehensive Waste Treatment Method Suitable for Villages and Towns - Google Patents

Abstract

The invention discloses a garbage comprehensive treatment method for village, which comprises the following steps: sorting life garbage of village to perishable element, combustible constituent, reclaiming element; inorganic element; allocating the perishable element, residues of crop, animal and poultry manure and water with mass ratio at 0. 8-1. 2:0. 8-1. 2:8; proceeding anaerobic fermentation under the insulation action of burning lose heat; generating marsh gas; burning the combustible constituent with combustion-supporting marsh gas completely; getting high temperature smoke gas; recovering thermal energy through the first and second heat exchanger; maintaining the temperature of marsh gas fermenting tank; obtaining resource utilization of marsh liquid or slag, marsh gas and reclaiming component; health-filling the inorganic element and burning ash slag. This invention can prevent twice pollution of the burning smoke gas, which can increase the efficiency and output of mash gas.

Description

A Comprehensive Waste Treatment Method Suitable for Villages and Towns

technical field

The invention relates to a garbage comprehensive treatment method suitable for villages and towns.

Background technique

Village and town garbage mainly includes three categories: livestock manure, household garbage and crop residues. According to statistics, in 2005, the annual output of village and town household garbage nationwide reached 120 million tons, and the annual output of livestock and poultry breeding waste exceeded 2 billion tons. At present, domestic garbage in villages and towns is mainly disposed of by direct dumping or open-air landfill, and the phenomenon of garbage encroaching on land and farmland and surrounding villages by garbage is serious. However, crop residues and plastics are mostly burned directly in the open air, and the smoke and other substances are extremely polluting to the environment. Therefore, the villages and towns in our country are generally dirty, chaotic and poor, which seriously affects the process of building a new socialist countryside.

Incineration and anaerobic fermentation technology are effective means of waste disposal. Incineration can not only realize the harmlessness, reduction, and stabilization of garbage, but also recover heat to realize resource utilization; while anaerobic fermentation can convert easily degradable organic matter into biogas such as methane to recover energy substances. Both are widely used in dealing with municipal waste.

Chinese patent 02147673.X discloses a fast and economical comprehensive treatment method for municipal solid waste, which roughly divides municipal solid waste into combustible parts, inorganic parts, metal parts (including batteries), and easily degradable organic parts; Part of it is sent to the incinerator connected to the entrance of the rotary drum dryer for incineration; the part of easily degradable organic matter is dried in the rotary drum dryer by using the high-temperature flue gas of incineration, and is directly used as fertilizer or incinerated. This method effectively solves the harmless and recyclable problems of municipal solid waste, but it still has the following disadvantages when it is used to deal with more complicated village and town garbage: 1) The calorific value of village and town garbage is low, and a large amount of fuel oil or combustion-supporting gas is required for incineration, and the treatment cost High; 2) Domestic garbage perishables, crop residues, livestock and poultry manure, etc. in village and town garbage are rich in organic matter. Drying alone cannot guarantee the quality of fertilizers, and direct incineration after drying is not conducive to resource utilization.

Chinese patent 200510094483.7 discloses a biogas production technology using kitchen waste, straw, livestock manure and activated sludge as raw materials. This technology mixes kitchen waste, straw, livestock and poultry manure, and activated sludge in a mass ratio of 1:1:1:1, and adds seed mud with an amount of 25% of the raw material, and maintains the temperature between 33 and 55°C. The gas production of fermentation products can be increased by 25-35%. However, this method requires high operating temperature, which is difficult to realize in villages and towns, especially in winter when the weather is cold, microbial activity is inhibited, and anaerobic fermentation is difficult to achieve the desired effect.

Therefore, at present, there is still a lack of comprehensive treatment and disposal methods suitable for the environment of villages and towns, and in line with the characteristics of various types and complex properties of village and town garbage.

Contents of the invention

The purpose of the present invention is to provide a comprehensive garbage treatment method suitable for villages and towns with a relatively concentrated population and a large amount of garbage production in view of the characteristics of the village and town environment and garbage components, so as to realize the harmlessness, reduction and resource utilization of village and town garbage.

For reaching above-mentioned purpose, the present invention comprises the following steps for the comprehensive processing method of village and town refuse:

1) Collect domestic waste, livestock and poultry manure and crop residues by classification, and sort domestic waste into four categories: perishable components, combustible components, recycled components and inorganic components;

2) Put the perishable components of livestock and poultry manure, crop residues and domestic waste into the biogas fermentation tank, and the weight ratio of the materials is livestock and poultry manure:perishable garbage and crop residues:moisture=0.8～1.2:0.8～1.2: 8. Keep the temperature in the fermentation tank at 35-55°C, and produce biogas by anaerobic fermentation;

3) Send the combustible components of domestic waste to the incineration plant, put them into the incinerator after fermentation and dehydration, and use biogas to support combustion and incineration. After incineration, the ash and inorganic components of domestic waste are sent to the landfill. The discharged fly ash is solidified with cement and shipped out;

4) The flue gas produced by incineration is sent to the secondary combustion chamber, used for combustion with biogas, and incinerated at a temperature above 850°C. The flue gas discharged from the secondary combustion chamber passes through a cyclone separator to remove particles, and then is cooled to below 180°C by the first heat exchanger. Then send it to the flue gas purification system, purify and discharge up to standard;

5) The high-temperature steam generated by the first heat exchanger enters the second heat exchanger, and after being cooled by heat exchange, it generates medium-temperature water of 30-60°C, which is input into the coil pipes wound outside the biogas fermentation tank to provide fermentation temperature.

The beneficial effects of the present invention are:

1. Harmless incineration and reduction of combustible components

The combustible components of domestic garbage, such as plastics and rubber, are difficult to degrade in nature. The invention incinerates the combustible components in domestic garbage, with a reduction rate of more than 90%, effectively solving white pollution in villages and towns. However, the combustible components of domestic waste in villages and towns have high water content and low calorific value, which makes it difficult to meet the temperature requirements for incineration. In the present invention, the biogas produced by anaerobic fermentation is introduced into the incinerator and the secondary combustion chamber to support combustion. Since the methane concentration in the biogas is between 60% and 70%, and the calorific value is 20000 ~ 29000kJ/ ^m3 , the temperature in the incinerator can be increased. Effectively promote waste incineration and reduce the generation of harmful substances such as dioxins. At the same time, the high-temperature incineration flue gas is cooled and passed through the flue gas treatment system, which can further control the concentration of dioxins, so that the exhausted flue gas can meet the national emission standards and achieve harmlessness.

2. Maximization of biogas fermentation resources

The perishable components of domestic waste, crop residues, and livestock and poultry manure are all good raw materials for anaerobic fermentation to produce biogas. However, biogas fermentation is greatly affected by seasonal changes, especially in northern winter when the temperature is low, and the microbial activity in the fermentation tank is inhibited, which affects the biogas production. In the present invention, the three are mixed and fermented anaerobically to increase the fermentation substrate. And by recovering the waste heat from incineration, the temperature of the anaerobic fermentation tank is kept between 35 and 55°C, the activity of microorganisms is improved, and the biogas output per unit of fermentation product is increased. The biogas produced by anaerobic fermentation is a good clean energy, which can effectively replace petroleum gas, coal and other fuels to meet the needs of incineration and village energy. Biogas slurry and biogas residue are rich in organic matter, nitrogen and phosphorus, and can be directly used for land use, such as vegetable and fruit tree fertilizers, to improve land fertility and increase crop production; they can also be used in aquaculture, such as fish farming.

3. Realize the comprehensive disposal of garbage in villages and towns

The invention effectively combines anaerobic fermentation and incineration technology, achieves the purpose of harmless, reduction and resource utilization of village and town garbage such as domestic garbage, livestock and poultry manure, and crop residues, and improves the living environment of villages and towns.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Detailed ways

With reference to Fig. 1, the garbage comprehensive treatment method suitable for villages and towns of the present invention comprises the following steps:

1) Collect domestic waste, livestock and poultry manure and crop residues by classification, and sort domestic waste into four categories: perishable components, combustible components, recycled components and inorganic components;

The perishable components of the above-mentioned domestic waste include leftovers, fruit peels, vegetable leaves, etc. The combustible components of domestic waste include plastics, rubber, textiles, wood blocks, etc. The recycled components of domestic waste include electrical appliances, scrap iron, glass bottles , plastic bottles, paper, etc., and the inorganic components of domestic waste include stones, sand, broken glass, large pieces of animal bones, etc.

The recovered components of domestic waste are sold to waste recycling companies, and the reuse of waste has certain economic value.

2) Put the perishable components of livestock and poultry manure, crop residues and domestic waste into the biogas fermentation tank, and the weight ratio of the materials is livestock and poultry manure:perishable garbage and crop residues:moisture=0.8～1.2:0.8～1.2: 8. Keep the temperature in the fermentation tank at 35-55°C, and produce biogas by anaerobic fermentation;

Generally, livestock and poultry manure and perishable garbage are added to the biogas fermentation tank every day, and crop residues are added to the biogas fermentation tank every 5 to 10 days.

A coil is arranged outside the anaerobic fermentation tank, and medium-temperature water generated by heat exchange of incineration flue gas is passed into the coil, and the temperature in the fermentation tank can be maintained by using the medium-temperature water to increase microbial activity. At the same time, add a paddle stirrer to the fermentation tank, and turn it on once every other day to stir the material to prevent local acidification. After the biogas produced by fermentation is collected by the gas collection tank, it is introduced into the incinerator and the second combustion chamber through the pipeline to increase the incineration temperature; the rest is put into the fuel tank through pressurized liquefaction and used as civil fuel; the biogas slurry and biogas residue can be directly mixed for agricultural use, or in the The solid and liquid are separated by sedimentation in the container, and the solid and liquid are used separately.

3) Send the combustible components of domestic waste to the incineration plant, put them into the incinerator after fermentation and dehydration, and use biogas to support combustion and incineration. After incineration, the ash and inorganic components of domestic waste are sent to the landfill. The discharged fly ash is solidified with cement and shipped out;

4) The flue gas produced by incineration is sent to the secondary combustion chamber, used for combustion with biogas, and incinerated at a temperature above 850°C. The flue gas discharged from the secondary combustion chamber passes through a cyclone separator to remove particles, and then is cooled to below 180°C by the first heat exchanger. Then send it to the flue gas purification system, purify and discharge up to standard;

Usually, a high-pressure blower is used to blow biogas into the secondary combustion chamber to increase the turbulence of the gas in the secondary combustion chamber, control the residence time of high-temperature flue gas in the secondary combustion chamber for more than 2 seconds, and reduce the generation of harmful substances such as dioxins. Use the first heat exchanger to quickly cool the high-temperature flue gas below 180°C, which can prevent dioxins from repolymerizing; the flue gas is adsorbed and filtered through dry desulfurization and acid removal towers, bag filter, activated carbon dust removal and other devices, so that the flue gas can be obtained Purify and meet emission standards.

5) The high-temperature steam generated by the first heat exchanger enters the second heat exchanger, and after being cooled by heat exchange, it generates medium-temperature water of 30-60°C, which is input into the coil pipes wound outside the biogas fermentation tank to provide fermentation temperature.

The high-temperature steam from the first heat exchanger enters the second heat exchanger, and the cooling water is used to absorb the heat in the steam to generate medium-temperature water at 30-60°C. Medium-temperature water enters the coil outside the anaerobic fermentation tank through the pipeline to heat the materials in the tank. The cooled steam is converted into liquid water, which flows back to the first heat exchanger and continues to be used to cool the high-temperature flue gas.

Claims (2)

1. method for comprehensively treating rubbish that is suitable for villages and small towns may further comprise the steps:

1) categorised collection domestic refuse, feces of livestock and poultry and crop residues sort domestic refuse, are divided into perishable composition, combustiblecomponents, recovery composition and inorganic components four classes;

2) the perishable composition of feces of livestock and poultry, crop residues and domestic refuse is put into marsh gas fermentation pool, the weight ratio of material is a feces of livestock and poultry: the perishable composition and the crop residues of domestic refuse: moisture=0.8～1.2:0.8～1.2:8, keep the interior temperature of marsh gas fermentation pool at 35～55 ℃, anaerobically fermenting is produced biogas;

3) combustiblecomponents of domestic refuse is sent into incineration plant, after heap ferment dehydration, put into incinerator,, burn the lime-ash of discharging the back and the inorganic components of domestic refuse and all send the landfill yard landfill, burn the flying dust of discharging the back and transport outward after with cement solidification with the combustion-supporting burning of biogas;

4) burn the flue gas that produces and send into dual firing chamber, combustion-supporting with biogas, burning more than 850 ℃, the flue gas that dual firing chamber discharges is removed particle through cyclonic separator, by below first heat exchanger cooling to 180 ℃, send into flue gas purification system more then, purify qualified discharge;

5) high-temperature vapour of first heat exchanger generation enters second heat exchanger, generates 30～60 ℃ middle warm water after the heat exchange cooling, in the coil pipe of input outside marsh gas fermentation pool, provides leavening temperature.

2. method for comprehensively treating rubbish according to claim 1 is characterized in that the combustion-supporting biogas of dual firing chamber blasts with gas blower.

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