Study on the supply capacity of crop residue as energy in rural areas of Heilongjiang province of China

Heilongjiang is the most northeastern province of China. The climate of Heilongjiang consists of very cold winters, leading to large energy demands for space heating by local residents. Rich food crop yields in Heilongjiang results in large amounts of crop residues. To fully accommodate rural energy demand and facilitate the effective utilization of crop residues, this study builds a mathematical model of supply capacity of crop residues as energy, then, based on the data from a field survey and literature review, calculates the local annual effective heat demands for living, the supply rates for effective heat of different crop residue utilization patterns, and the supply capacities of crop residues as energy in rural areas of Heilongjiang. Results show that the supply capacity of traditional direct burning of crop residues is less than 1, indicating that direct burning of crop residues cannot fully supply rural living heat demands. The supply capacity of densification is more than 1.6, indicating that introducing densification can not only achieve full supply for rural living heat demands, but also result in a large proportion of crop residues remaining for other uses. Because part of the crop residues is converted to products other than gas, dry distillation can only supply 55% of the rural living heat demands. Introducing efficient technologies of crop residue utilization for energy in rural areas of Heilongjiang can make the available amount of energy from crop residues larger than the amount of energy demand. This study found that the combination of densification and dry distillation of crop residues can be used as a high-efficiency centralized supplement of living heat, achieving multiple benefits such as use of alternatives to fossil fuel energy, economic development, environment protection, and improvement in quality of life.