CN103586263B - Urban garbage aerobiotic-anaerobic biological drying method without external heat source - Google Patents

Abstract

The invention relates to an urban garbage aerobiotic-anaerobic biological drying method without an external heat source, which comprises the following steps: firstly, carrying out primary crushing and stacking on urban garbage; then carrying out aerobiotic-anaerobic fermentation on a garbage heap in a mode of keeping the internal temperature in the range of 40 to 65 DEG C and keeping the relative humidity in the range of 40 percent to 80 percent, wherein the fermenting period is 12 to 18 days; carrying out secondary crushing on the fermented urban garbage; finally, carrying out double separation of gravity and air classification to remove inorganic components in the urban garbage. According to the invention, under the condition without the external heat source, moisture content of the urban garbage is reduced to 15-40 percent from over 50 percent and a heat value of the urban garbage is increased to 1,800-3,000 kcal/kg from less than 1,000 kcal/kg, and thus, a harmless and resource disposal approach of the urban garbage is obviously widened and the urban garbage aerobiotic-anaerobic biological drying method without the external heat source can be widely applied to drying pretreatment on the urban garbage with high moisture content, low heat value and complex ingredients.

Description

A kind of aerobic-anaerobic biological drying method of urban garbage without external heat source

technical field

The invention relates to a pretreatment technology for drying urban domestic garbage, and the invention relates to an aerobic-anaerobic biological drying method for urban garbage without an external heating source.

Background technique

In recent decades, with the rapid development of my country's economy and society, urbanization has progressed rapidly, and the urbanization rate has exceeded 50%. While improving the quality of life of residents and promoting economic and social prosperity, urbanization has also brought about some prominent social and environmental problems. Among them, urban garbage and the environmental pollution caused by it have become one of the major problems that need to be solved urgently in the current urban construction and development. Up to now, the total amount of garbage piled up in my country over the years has exceeded 3 billion tons. The current disposal and utilization methods of urban waste, such as landfill, incineration and composting, face problems such as large land occupation, high processing costs, and easy to cause secondary pollution. It is difficult to meet the harmless and resource-based urban waste in the new era disposition requirements. Drying pretreatment of urban waste to reduce its moisture content and increase its calorific value has become a widely used urban waste disposal method at home and abroad.

Due to the complex composition, high water content and low calorific value of urban waste in my country, one of the important tasks of the existing municipal waste drying pretreatment technology is to reduce the moisture content of waste, which can not only increase its calorific value, but also reduce Improve its cohesiveness, which is beneficial to crushing, sorting and other processes. In the patent "A Harmless Domestic Garbage Incineration Treatment System and Treatment Method", the method of drying with a dryer is used to reduce the moisture content in the garbage. Although this method can effectively reduce the moisture content in the garbage, it increases the amount of garbage in the garbage. The cost of drying; the patent "A Hydrolysis-Aerobic Two-Stage Biological Drying Method for Household Garbage" uses a combination of hydrolysis and aerobic fermentation, supplemented by turning over piles to dry urban garbage, although no external heat source is required , but the fuel consumption and power consumption required by the turning equipment, as well as the easy damage of the turning machinery and the consumption of spare parts also increase the operating cost and technical difficulty.

Contents of the invention

The technical problem to be solved by the present invention is to provide an aerobic-anaerobic biological drying method for urban waste without external heating source in view of the above-mentioned deficiencies in the prior art, so as to realize the process of urban waste without external heating source and turning equipment. The drying pretreatment process can greatly increase its calorific value while reducing the water content of urban waste, which is easy to operate, low in cost and high in efficiency.

The technical scheme that the present invention adopts for solving the above-mentioned problem is:

An aerobic-anaerobic biological drying method for urban waste without external heating source, which includes the steps of primary crushing, aerobic-anaerobic fermentation, secondary crushing, sorting, etc. The specific steps are:

(1) Primary crushing: crushing and stacking urban waste into rubbish heaps;

(2) Aerobic-anaerobic fermentation: carry out aerobic-anaerobic fermentation on the above-mentioned garbage pile, and by controlling the wind speed blowing to the garbage pile, the average temperature of the garbage pile is kept at 40-65°C, and the relative temperature of the garbage pile is kept The ambient humidity is 40% to 80%;

(3) Secondary crushing: Secondary crushing of fermented urban waste;

(4) Sorting: The secondary crushed municipal waste is separated into heavy particles and light particles through gravity-wind separation, and the obtained light particles are dry waste with calorific value.

In the above scheme, the crushing in the step (1) crushes the particle size of the municipal waste to below 200 mm, so as to facilitate the subsequent fermentation.

In the above solution, the step (1) is to pile the primary crushed municipal waste in a rectangular or circular waste dump pool, and control the stacking height to be 4m-7m.

In the above solution, the wind speed blowing to the garbage dump in the step (2) is 0.1-1.5m/s.

In the above scheme, the aerobic-anaerobic fermentation cycle of the step (2) is 12-18 days.

In the above scheme, in the aerobic-anaerobic fermentation cycle of the step (2), the first 8 to 12 days are aerobic fermentation, and the wind speed blowing to the garbage dump is 0.6 to 1.5 m/s; the next 4 to 6 days are anaerobic fermentation. Oxygen fermentation, the wind speed blowing to the garbage dump is 0.1~0.6 m/s.

In the above solution, the wind blowing to the garbage pile in the step (2) blows from the bottom of the garbage pile to the top of the garbage pile.

In the above scheme, the odor generated by the aerobic-anaerobic fermentation in the step (2) is collected by a fan arranged above the garbage dump.

In the above scheme, the secondary crushing in the step (3) is to crush the fermented municipal waste again so that the particle size is below 50 mm.

In the above scheme, the gravity-wind separation in the step (4) uses a wind speed of 2.0-4.0 m/s.

In the above scheme, the heavy particles in the step (4) are separated by a magnetic separation device and eddy current to remove ferrous metals and non-ferrous metals, and finally obtain inorganic components without calorific value.

Compared with prior art, the beneficial effect of the present invention is:

First, the present invention utilizes the biodegradation in urban waste to generate heat, supplemented by ventilation to control a certain temperature and humidity, and realizes the drying pretreatment process of urban waste without an external heating source and without turning equipment, and is effective in reducing the content of urban waste. At the same time, the calorific value is greatly increased, and it has the characteristics of easy operation, low cost and high efficiency, and can be widely used in the drying pretreatment of urban garbage in our country.

Second, the method of the present invention includes steps such as primary crushing, aerobic-anaerobic fermentation, secondary crushing, and sorting, which can reduce the moisture content of urban waste from greater than 50% to 15% to 40%, and the calorific value is as small as Increase from 1000 kcal/kg to 1800 kcal/kg-3000 kcal/kg, which significantly broadens the way of harmless and resourceful disposal of municipal waste.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with examples, but the present invention is not limited only to the following examples.

Example 1:

A method for aerobic-anaerobic biological drying of urban waste without an external heating source, the specific steps are:

(1) Primary crushing: Send municipal waste into the primary crusher to reduce the particle size of the waste to less than 200mm, and then transport the crushed waste to the waste dump pool for accumulation. The garbage dump pool is rectangular with a total width of 68m. In order to facilitate the subsequent biological fermentation, the accumulation height of the garbage pile is 6m, and it is divided into 17 parallel layings, each with a width of 4m and a length of 20m. The ventilation channel opening is used to control the ventilation speed, which can control the temperature required for aerobic-anaerobic fermentation. Of course, it is also used to collect garbage leachate. There is a fan on the upper part of the garbage pile to control the wind speed on the upper part of the garbage pile to collect garbage. fermented odor;

(2) Aerobic-anaerobic fermentation: The garbage dump pool is located in a semi-enclosed factory area, the relative humidity is controlled at 80%, the internal temperature of the garbage dump is 45°C, and the fermentation cycle is 12 days. The first 8 days are aerobic fermentation. The fan controls the wind speed of the vent at the bottom of the garbage dump at 0.6m/s; the last 4 days are anaerobic fermentation, and the fan controls the wind speed of the vent at the bottom of the garbage dump at 0.1m/s; (Note: Aerobic-anaerobic fermentation The heat generated by the garbage is different during the process, so the wind speed is different, but the temperature can be controlled at 45°C)

(3) Secondary crushing: Secondary crushing of the fermented municipal waste to control its particle size below 50mm to facilitate its combustion and heat release.

(4) Sorting: The municipal waste after secondary crushing enters the gravity screening machine supplemented by wind sorting. The wind speed is controlled at 2.0 m/s. The underscreen of the screening machine is the separated heavy particles, mainly inert materials. Then go through a magnetic separation device and an eddy current separator to remove ferrous metals and non-ferrous metals, and then obtain inorganic components without calorific value, which enter the warehouse of inorganic components without calorific value; the light particles separated by the gravity screening machine are those with calorific value. Dry the garbage and enter the dry garbage warehouse with calorific value.

The actual measurement results show that: the average treatment capacity of 350t/d, the initial moisture content of municipal waste is 69.7%, the moisture content after drying pretreatment is reduced to 27.5%, and the average daily low calorific value is 2331.2 kcal/kg. Garbage 135 d/t, can be used as derived fuel and widely used in power plants, cement plants, etc.

Example 2:

What this embodiment deals with is unsorted raw urban waste, with a moisture content of 63.9%, which is mainly divided into two categories: inorganic, mainly including inert materials such as various lime, bricks, ceramics, glass and metals, etc. , accounting for 18.36% of the total garbage; organic, mainly including crops, paper, rubber and plastic, textiles and kitchen waste, accounting for 81.64% of garbage, organic is the main source of calorific value. The processing capacity is 350 tons/day.

A method for aerobic-anaerobic biological drying of urban waste without an external heating source, the specific steps are:

(1) Primary crushing: Send municipal waste into the primary crusher to reduce the particle size of the waste to less than 200mm, and then transport the crushed waste to the waste dump pool for accumulation to facilitate subsequent biological fermentation. The accumulation height is 6m , the garbage dump pool is rectangular, with a total width of 68m. The garbage dump is divided into 17 parallel lines, each with a width of 4m and a length of 20m. Each garbage dump works in turn to achieve continuous treatment of urban garbage; the bottom of the garbage dump pool is equipped with The ventilation channel opening is used to control the ventilation speed, which can control the temperature required for aerobic-anaerobic fermentation. Of course, it is also used to collect garbage leachate. There is a fan on the upper part of the garbage pile to control the wind speed on the upper part of the garbage pile to collect garbage. fermented odor;

(2) Aerobic-anaerobic fermentation: The garbage dump pool is located in a semi-enclosed factory area, the relative humidity is controlled at 60%, the internal temperature of the garbage dump is 53°C, and the fermentation period is 14 days. The first 9 days are aerobic fermentation. The fan controls the wind speed at the bottom vent of the garbage dump pool at 1.0m/s; the last 5 days are anaerobic fermentation, and the fan controls the wind speed at the bottom vent of the garbage dump pool at 0.3m/s;

(3) Secondary crushing: Secondary crushing of the fermented municipal waste to control its particle size below 50mm to facilitate its combustion and heat release;

(4) Sorting: The secondary crushed urban waste enters the gravity screening machine supplemented by wind sorting. The wind speed is controlled at 2.5 m/s. The underscreen of the screening machine is the separated heavy particles, mainly inert materials. Then go through a magnetic separation device and an eddy current separator to remove ferrous metals and non-ferrous metals, and then obtain inorganic components without calorific value, which enter the warehouse of inorganic components without calorific value; the light particles separated by the gravity screening machine are those with calorific value. Dry the garbage and enter the dry garbage warehouse with calorific value.

The actual measurement results show that: the average treatment capacity of 350t/d, the initial moisture content of urban waste is 63.9%, the moisture content after drying pretreatment is reduced to 23.1%, and the average daily low calorific value is 2453.6 kcal/kg. Garbage 138 d/t, can be used as derived fuel and widely used in power plants, cement plants, etc.

Example 3:

What this embodiment deals with is unsorted raw urban waste, with a moisture content of 60.4%, which is mainly divided into two categories: inorganic, mainly including inert materials such as various lime, bricks, ceramics, glass and metals, etc. , accounting for 21.54% of the total garbage; organic, mainly including crops, paper, rubber and plastic, textiles and kitchen waste, accounting for 78.46% of garbage, organic is the main source of calorific value. The processing capacity is 350 tons/day.

A method for aerobic-anaerobic biological drying of urban waste without an external heating source, the specific steps are:

(1) Primary crushing: Send municipal waste into the primary crusher to reduce the particle size of the waste to less than 200mm, and then transport the crushed waste to the waste dump pool for accumulation to facilitate subsequent biological fermentation. The accumulation height is 6m , the garbage dump pool is rectangular, with a total width of 68m. The garbage dump is divided into 17 parallel lines, each with a width of 4m and a length of 20m. Each garbage dump works in turn to achieve continuous treatment of urban garbage; the bottom of the garbage dump pool is equipped with The ventilation channel opening is used to control the ventilation speed, which can control the temperature required for aerobic-anaerobic fermentation. Of course, it is also used to collect garbage leachate. There is a fan on the upper part of the garbage pile to control the wind speed on the upper part of the garbage pile to collect garbage. fermented odor;

(2) Aerobic-anaerobic fermentation: The garbage dump pool is located in a semi-enclosed factory area, the relative humidity is controlled at 50%, the internal temperature of the garbage dump is 60°C, and the fermentation cycle is 18 days. The first 12 days are aerobic fermentation. The fan controls the wind speed at the bottom vent of the garbage dump pool at 1.5m/s; the last 6 days are anaerobic fermentation, and the fan controls the wind speed at the bottom vent of the garbage dump pool at 0.6m/s;

(3) Secondary crushing: Secondary crushing of the fermented municipal waste to control its particle size below 50mm to facilitate its combustion and heat release;

(4) Sorting: The secondary crushed urban waste enters the gravity screening machine supplemented by wind sorting. The wind speed is controlled at 3.0 m/s. The underscreen of the screening machine is the separated heavy particles, mainly inert materials. Then go through a magnetic separation device and an eddy current separator to remove ferrous metals and non-ferrous metals, and then obtain inorganic components without calorific value, which enter the warehouse of inorganic components without calorific value; the light particles separated by the gravity screening machine are those with calorific value. Dry the garbage and enter the dry garbage warehouse with calorific value.

The actual measurement results show that: the average treatment capacity of 350t/d, the initial moisture content of municipal waste is 60.4%, the moisture content after drying pretreatment is reduced to 24.6%, and the average daily low calorific value is 2631.7 kcal/kg. Garbage 140 d/t, can be used as derived fuel and widely used in power plants, cement plants, etc.

Claims (6)

1. A method for aerobic-anaerobic biological drying of urban waste without external heating source, characterized in that it comprises primary crushing, aerobic-anaerobic fermentation, secondary crushing and sorting, and the concrete steps are: (1) Primary crushing: crushing and stacking urban waste into garbage dumps; (2) Aerobic-anaerobic fermentation: carry out aerobic-anaerobic fermentation on the above-mentioned garbage pile, and by controlling the wind speed blowing to the garbage pile, the average temperature of the garbage pile is kept at 40-65°C, and the relative temperature of the garbage pile is kept The ambient humidity is 40% to 80%; (3) Secondary crushing: Secondary crushing of fermented urban waste; (4) Sorting: The secondary crushed urban waste is separated into heavy particles and light particles through gravity-wind separation, and the obtained light particles are dry waste with calorific value; The crushing in the step (1) crushes the particle size of the urban waste to below 200 mm; the step (1) is to pile the primary crushed urban waste in a rectangular or circular garbage dump pool, and control the stacking height In the aerobic-anaerobic fermentation cycle of the step (2), the first 8 to 12 days are aerobic fermentation, and the wind speed blowing to the garbage dump is 0.6 to 1.5 m/s; the next 4 to 6 days are For anaerobic fermentation, the wind speed blowing to the garbage dump is 0.1~0.6 m/s. 2. The method of aerobic-anaerobic biological drying of urban waste without external heating source according to claim 1, characterized in that the aerobic-anaerobic fermentation cycle of the step (2) is 12-18 days. 3. The method for aerobic-anaerobic biological drying of municipal garbage without external heating source according to claim 1, characterized in that the wind blowing to the garbage dump in the step (2) blows from the bottom to the top of the garbage dump. 4. A method of aerobic-anaerobic biological drying of urban garbage without external heating source according to claim 1, characterized in that the odor generated by the step (2) aerobic-anaerobic fermentation is provided in the garbage The fan above the pile collects it. 5. A method for aerobic-anaerobic biological drying of urban waste without external heat source according to claim 1, characterized in that the secondary crushing in the step (3) is to carry out fermented urban waste Crushed again to make the particle size below 50 mm. 6. The aerobic-anaerobic biological drying method for municipal waste without external heating source according to claim 1, characterized in that in the step (4), the heavy particles are separated by magnetic separation device and eddy current to remove black Metals and non-ferrous metals can be used to obtain non-calorific inorganic components; the gravity-wind separation in the step (4) uses a wind speed of 2.0-4.0 m/s.