Li Haijun
Abstract: Domestic biomass pellet fuel stove is a new type of cooking stove. It is the replacement product of the current traditional stove, and it has good economic and social benefits.
1 Introduction
At present, the research and development of biomass energy technology has become one of the hot topics in the world and has attracted the attention of governments and scientists from all over the world. Many countries have formulated research and development plans, such as Japan's sunshine plan, India’s green energy project, and the United States’ Energy farms, etc., in which the development and utilization of biomass energy occupies a considerable share. Many foreign biomass energy technologies and devices have reached the level of commercial application, compared with other biomass energy technologies, biomass particle fuel technology is easier to achieve large Scale production and use. The ease of use of biomass pellets is comparable to gas, fuel and other energy sources.
Taking the United States, Sweden and Austria as examples, the scale of application of biomass energy accounts for 4%, 16% and 10% of the country’s disposable energy consumption. In the United States, the total installed capacity of biomass energy has exceeded 1 Million MW, stand-alone capacity of 10 ~ 25MW; in Europe and the United States, biomass pellet fuels for general household use and supporting efficient heating and heating stoves have been very popular. China attaches great importance to the development and utilization of biomass energy. Since the 1980s , The Chinese government has always listed the research and application of biomass energy utilization technologies as a key scientific and technological research project, carried out the research and development of new technologies for the utilization of biomass energy, and further improved the biomass energy technology. However, the biomass energy of China The research mainly focuses on large and medium-sized livestock farm biogas engineering technology, straw gasification centralized gas supply technology and landfill power generation technology, etc. The research on production, processing and direct combustion of biomass particle fuel products has just started. Some universities and scientific research institutes have carried out research on biomass particle molding technology and achieved certain results.
Relevant experts and technicians have studied and analyzed the combustion dynamics characteristics of biomass pelleted fuels. Based on the characteristics of biomass fuels with high volatile content and low flash point, the research and design of gasification for the combustion of biomass pellets specifically Integration of cooking stoves.
As a supporting combustion facility of the biomass cold-formed pellet fuel processing equipment system, the stove adopts the gasification combustion technology, which is easy to operate, easy to ignite, has large firepower intensity and is easy to control, and has high thermal efficiency, and only needs to input proper amount of granular fuel at one time. In the hopper, an additional knob is used to adjust the amount of fuel injected during combustion, so as to regulate the size of the firepower. The combustion state is exactly the same as when the raw materials such as straw and wood are burned, and there is no smoke and no smell. Because there is sufficient combustion, there is basically no ash. The method is similar to that of coal-fired stoves, but it is cleaner than coal-fired stoves. It is safer than gas stoves. It provides a green, safe and safe green consumption method for cities, rural life energy and industrial energy. It is the current firewood stove. , The upgrading of coal-saving stoves is widely used in the life of rural residents.
2 Design of Biomass Pellet Fuel Cooking Furnace
2.1 Structural arrangement of biomass forming pellet fuel cooking furnace
The biomass pelletizing fuel cooking stove designed uses a double-layer furnace structure, ie, the space between the inner and outer furnaces is a secondary air duct. The primary air duct and the wind deflector, the secondary air duct and the wind deflector, the feeding port, and the water Cover, furnace, furnace, radiant heating surface, cooktop, pot ring, fire ring, flue, chimney and other components, its structural arrangement as shown in Figure 1. Double furnace grate on the door is always open, as For fuel and air supply purposes; Primary air ducts and wind deflectors are used to supply furnace air and adjust the combustion gasification rate of the fuel in the furnace. Secondary air ducts and wind deflectors are used to supply air to the cooktop and adjust the combustion of the gas. Speed and condition. There is a water jacket in the upper part of the furnace body for absorption of waste heat. To prevent short circuit of the flue gas, a ring-shaped ring fire ring is installed at the upper outlet side of the furnace body.
2.2 The working principle of biomass pelletizing cooking stove
Biomass pellet fuel is added to the furnace chamber in the furnace through the inlet of the fuel furnace. The pellet fuel is ignited through the primary air channel. After the particulate fuel is burned, the wind deflector of the primary air duct is adjusted to make the pellet fuel oxygen-free and combust. Gas; At the same time adjust the wind deflector of the secondary air duct, so that the combustible gas generated is burned at the mouth of the burner. When the production of biomass pellet fuel is finished, adjust the wind deflector of the primary air duct and adjust the stop of the secondary air duct. The wind plate, so that the residual carbon continues to burn until it burns out. The water jacket can absorb the flue and the side of the furnace waste heat, in order to improve the thermal efficiency of the furnace.
3Benefit Analysis of Biomass Pellet Fuel Cooking Furnace
The development of a biomass granulated cooking furnace for smelters is open to millions of households. The market is vast. In the long run, its viability will still depend on economic and social benefits. For a family, biomass pellets The viability of the cooking stove will depend on whether the user of the product can afford it, can afford it, and can use it. Therefore, for a biomass pelletizing cooking stove, a coal-fired stove, a biomass stover stove, that is, a conventional firewood stove Fire speed, fire intensity of cooking, fuel consumption, cooking efficiency, thermal efficiency parameters such as waste heat efficiency, and CO, NO in exhaust fumes x, SO 2, Smoke temperature, exhaust dust concentration and other environmental indicators were compared to analyze the economic benefits and social benefits of the biomass pelleted cooking stove.
3.1 Economic benefits
There are two parts of the economic benefits of biomass pelleted cooking stoves, one part is the efficiency of production companies, and the other is the user benefits.
3.1.1 Benefits of Production Enterprises
3.1.1.1 Health-producing material molding pellet fuel cooking stove business benefits
Compared with other similar products, the biomass pelleted cooking stove has a relatively simple production process and a relatively small investment in production. For enterprises that already have a basic production base for stoves, there is no need to add other special equipment, only according to the drawings and regulations. Production process production, the spare part of the materials used for the flow of funds can be put into the production of biomass pellet fuel cooking furnace, each cost is only 200 to 300 yuan, a considerable profit.
3.1.1.2 Benefits of Producing Matter Forming Particle Fuels
Biomass-produced pellet fuel is mainly used to recover various biomass straws from farmer's farmland for comminution. Biomass pellets are then made from biomass pelletizers and sold to farmers for cooking. If a company produces 10 tons of material forming particles, the annual output can reach 3,600 tons, the recycling price of biomass straw is 0.2 yuan per kilogram, the sale price of biomass forming pellets is 0.5 yuan per kilogram, deducts the expenses of electricity, workers' wages, equipment depreciation, etc. The net profit per kilogram of biomass molding particles is 0.1 yuan, and the annual net profit can reach 3.6 million yuan.
3.1.2 user benefits
3.1.2.1 Compared with direct combustion of similar materials
(1) Waste materials. Traditional rural old-style pots, with an overall efficiency of 12% to 15%. Due to incomplete combustion, large smoke, low firepower, and low heat transfer efficiency, this efficiency is only about 12%. Use of biomass molding The total efficiency of the pellet fuel cooking stove is 30%~40%, which can save materials 2~3 times.
(2) Save money. According to statistics, each farmer in China can produce straw firewood of up to 6000kg per year. According to the current average market price of RMB 0.2/kg, it can generate income of RMB 1,200 per year. Use biomass pelletizing fuel for cooking furnace, actual daily About 5kg of biomass pelleted fuel (about three meals a day) needs 0.5 yuan/kg x 5kg=2.5 yuan/day, and 900 yuan/year. Compared with the use of traditional rural cooking stoves, it can save nearly 300 yuan in 1 year.
(3) Save time. The combustion of biomass pelletizing cooking furnace produces high combustion intensity of the gas, quick heating, and saves time. The old pot boiling 5kg water takes 25~30min; the biomass forming pellet fuel cooking furnace is 12~ 15min, saving half the time.
(4) Labor force in the province. When cooking in an old-fashioned stove, it requires special or semi-labour to add firewood. The biomass pelletizing cooking stove does not need to be supervised under normal circumstances and it is automatically burned.
3.1.2.2 Compared with coal fired boilers
(1) Save money. Burning coal, According to the statistics, the energy consumption of 10kg coal is required for each farmer in China during the cooking day. According to the current market average coal price of 360 yuan/t, the daily coal consumption fee is 3.6 yuan; Formed pellet fuel cooking furnace, the actual daily consumption (three meals) 5kg biomass pelleted fuel, daily needs 0.5 yuan / kg x 5kg = 2.5 yuan, 1 year can save nearly 400 yuan.
(2) Biomass pelletized cooking stoves are cleaner than coal-fired boilers.
3.1.2.3 Compared with LPG
The most intuitive advantage of using biomass pelleted cooking stoves is to save money. The average price of a can of liquefied petroleum gas is RMB 75/can, and the daily consumption of liquefied gas is RMB 3.5. If you use a biomass pelletizing fuel cooking furnace, The actual daily consumption (three meals) of 5kg biomass pelleted fuel requires 0.5 yuan/kg x 5kg=2.5 yuan/day, which can save nearly 360 yuan in one year.
It can be clearly seen from the above that the use of a biomass pelleted cooking stove has a low operating cost and significant economic benefits, far exceeding that of other conventional energy products.
In order to more clearly demonstrate the economics of using biomass pelleted cooking stoves, a four-person family is taken as an example. The economics of using different stoves are shown in Table 1:
In summary, using a biomass pellet fuel cooking furnace, compared with direct burning of straw and coal, the outstanding material is saving material, saving money, saving time and labor.
3.2 Social benefits
The efficiency of biomass pelletized cooking stoves is high. Normal households only need 4 to 5 kg of biomass pellets per day to meet their daily needs, improve the living conditions of farmers, and ensure that the farm kitchen can maintain a clean and hygienic environment. After promotion in rural areas, 90% of soot emissions can be reduced and the air can be purified with significant environmental benefits. During the combustion of biomass pellets, the main pollutants emitted are soot and dust. 2, NO xAnd CO. The emission concentration of the main pollutants in the coal stoves used in the comparison is shown in Table 2.
Each biomass pelletizing cooking furnace burns 180kg of straw each year, which can replace 115.2kg of coal and can reduce CO annually. 2About 265kg, SO 2About 1.84kg and smoke dust about 0.086kg (compared with 1.0% sulfur in coal, ash 21%).
4 Conclusion
The development of biomass pelletizing cooking furnaces has provided families with a family-type, small-scale biomass straw gasification and combustion integrated stove. It has broken through the use of straw gasification units that cannot be used in a single household, cannot be miniaturized, and difficult to popularize. The defects filled up the gaps in the country. The special stoves for biomass pellets were used to improve the civilization of their living comfort, saving time and labor, and significantly improving the environment and courtyard hygiene. At the same time the stove The development of the widened range of biomass straws has promoted the promotion and application of biomass gas supply, improved the utilization of straw more effectively, and reduced the pollution caused by the direct burning and burning of straw to the environment. The needs of modern society.
In short, the promotion of the application of biomass pelletizing cooking stoves is a feasible project for small and medium-sized enterprises, especially for rural enterprises with limited production and processing capacity, and relatively limited funds, in addition to being sturdy. Significant value-added and clean combustion have opened up a path of sustainable development. They are widely used in various fields and have greatly met people's thermal energy needs. Especially in rural markets, it is easy to popularize and popularize on a large scale and the market prospect is immeasurable.
