Abstract:Abstract: Technology of straw bale combustion is one of the effective ways to realize the clean utilization of agricultural residue, which has caused widespread concern. In this paper, the latest research progress of straw bale combustion was reviewed, the reaction principle and combustion characteristics of straw bale combustion were described, the generation and emission of particulate matter in the process of straw bale combustion were analyzed, such as NOx, CO and particle. And the research of straw bale combustion types, principles and characteristics were systematically summarized. Researchs showed that the combustion process of straw bale is mainly divided into two stages: volatile combustion and straw charcoal combustion. The heat released by volatile combustion accounted for more than 67% of the heat in the whole combustion process, which affected the combustion state of the whole straw bale.According to the technical characteristics and heating scale, we divided straw bale combustion into two types, one was continuous bale combustion, which can realize continuous feeding and ash cleaning in the combustion process, maintain a stable combustion state in the combustion chamber, and was suitable for the central heating area with large heating area, that mainly included cigar-bale combustion and reciprocating grate combustion. The other was batch combustion technology, which had advantages in small floor area, simple and convenient operation, usually used for small heating mechanism, and it included forward combustion technology and reverse combustion technology. Based on the global literature search, the research hotspot, institutions and development trend of straw bale combustion were analyzed. The running cost of straw baled heating was evaluated. It was found that the straw bale combustion has the characteristics of simple heating process and low operation cost. The operation cost was 19.8 yuan/m2, which was suitable for the industrialization promotion of clean heating in villages and towns. In addition, straw baled heating instead of coal heating can reduce the emission of SO2 by 0.38 kg per square meter and the emission of CO2 by 1.54 kg per year, which has a better benefit of environmental protection. In terms of technology popularization, the industrial system of straw bale combustion in developed countries in Europe is relatively mature, by contrast, the industrial system of straw bale combustion in China is still in the early stage, there are also some large-scale straw bale combustion projects in Liaoning province, Heilongjiang province, Hebei province and other areas, which have achieved good results. Straw bale combustion technology had gradually attracted the attention of scientific researchers. Developed countries in Europe had made some progress in the field of straw bale combustion, such as combustion mechanism, boiler structure, reduction of flue gas emission, etc. And at present, the research of combustion technology focuse on flue gas emission reduction and environmental impact assessment. The existing straw bale combustion technology still has some problems, such as insufficient combustion, unclear generation mechanism of flue gas pollutants, higher NOx and particle emission. It is suggested that we should pay more attention on research of characteristics of pollutant emission, and it is encouraged to reduce the generation of flue gas pollutants from the source.