Agricultural and forestry waste is an important member of wasteBiomass resources, is an important renewable resource. The conversion and utilization of agricultural and forestry waste energy is one of the research hotspots in the field of renewable energy.
Agricultural and forestry wastes mainly include straw, rice husk, edible fungus substrate, leftovers, firewood, bark, peanut shell, branch firewood, rolled bark, shavings, etc.
stayBiomass fuelFor power generation, the fuel is mainly traditional biomass energy agricultural and forestry waste.
Agricultural and forestry wastes contain a variety of available substances, including cellulose andhemicelluloseThey are two important ones.Cellulose is an important component of woody biomass and the most abundant renewable resource on the earth.Cellulose can be converted into clean fuel and chemical ethanol. The key to its conversion is to find an effective way to hydrolyze cellulose into soluble fermentation sugars such as glucose.
main features
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Agricultural and forestry wastes come from plants, mainly composed of C, H, O, N, S, etcPlant photosynthesisCompared with fossil energy such as oil, coal and natural gas, the products of
(1) Renewable.Well known traditionalFossil energyIt belongs to non renewable energy, and massive use of this kind of energy will face a serious energy crisis.Agricultural and forestry wastes come from plants and can be regenerated through plant photosynthesis. Solar energy, wind energy, tidal energy, etc. belong to renewable energy.
(2) Sustainability.The 12th Five Year Plan proposes the sustainability of social development, which also includes the sustainability of energy.Because agricultural and forestry wastes are renewable, their sustainability can be achieved through rational utilization and scientific planning.
(3) Rich resources.China is a large agricultural country, with diverse biomass types, wide distribution and rich resources.Research statistics show that China's agricultural and forestry waste reaches more than 700 million tons every year, and about 350 million tons can be used for energy purposes, equivalent to 180 million tons of standard coal. It is rich in resources and has great development potential.
(4) Diversified utilization.According to the characteristics of agricultural and forestry wastes, the utilization of agricultural and forestry wastes is mainly through: thermal conversion, biological conversion and other methods to convert them into biodiesel, fuel ethanol and other oxygenated fuels to replace fossil fuels.It can also be converted into electric energy for use by direct gasification.[1]
Research and utilization status
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As a part of biomass energy, the development and utilization of agricultural and forestry waste has attracted extensive attention and become a new hotspot in energy research and environmental field.Different waste resources have different possible utilization rates.
Since the 1980s, China has taken the utilization of biomass energy as a key scientific and technological breakthrough. After years of technical research and breakthrough, China's agricultural and forestry waste recycling mainly includes:
(1) Gasification of agricultural and forestry wastes for power generation.Gasification refers to the reaction of waste and gasification agent to generate small molecule combustible gas under high temperature for power generation.In addition to straw as the main raw material for power generation, there are also wood acoustic materials as the main raw material for power generation.Sunshine Kaidi New Energy Group Co., LtdWuhan Kaidi Power Co., Ltd. and its subsidiary Wuhan Kaidi Power Co., Ltd. have built many biomass power plants nationwide;In coastal areas, the power generation is mainly based on the energy of salt tolerant shrubs in the saline alkali land of the beach, which is mainly distributed in Dalian and Inner Mongolia;In desert areas, using shrub resources and agricultural and forestry residues as raw materials can not only obtain renewable energy, but also benefit the region in desertification control, employment, economy and other aspects.
(2) Wood briquettes.It mainly refers to obtaining heat energy through direct fuel of agricultural and forestry wastes, which is one of the main ways of utilization of agricultural and forestry wastes.The wood waste is compressed into rod shaped, granular and hard briquettes under high pressure. The briquette fuel can be used as boiler, household heating, etc., and can also be further processed into activated carbon.
(3) Liquefaction to prepare fuel ethanol.Liquefaction is the process of converting waste into liquid products by chemical means.Liquefaction mainly includes direct liquefaction and indirect liquefaction.Direct liquefaction is to put waste into high-pressure equipment and add catalyst to liquefy it into liquefied oil under certain conditions, which can be used as automobile fuel;Indirect liquefaction is to convert waste into gas and further synthesize it into liquid products, or to hydrolyze cellulosehemicelluloseIt is converted into polysaccharide and then fermented into ethanol.[2]
