Torrefaction of biomass materials has received a tremendous attention over the years due to its ability to produce a high-grade solid biofuel with enhanced durability, excellent grindability, higher bulk density and calorific value, and greater energy density, as compared to the original untreated biomass material. It is a mild pyrolysis treatment technology under inert atmosphere which can improve the chemical and physical properties of raw biomass through the elimination of oxygen, reduction of moisture content, and change of chemical compositions. When raw biomass is mildly pyrolyzed in a default-oxygen or N₂ atmosphere at moderate temperatures, the properties of raw biomass including low calorific value, hydrogen-carbon ratio, hygroscopicity, and grindability can be significantly enhanced. In the present review, the operating mechanism of different torrefaction processes including wet, dry, and ionic-liquid-assisted torrefaction is analyzed and discussed. More importantly, the reactor design for commercialization purpose, reaction kinetics and mechanism, economics, and sustainability of biomass torrefaction is discussed in detail. This review is extended to the torrefaction of agro-residue biomass since torrefied agro-residue-based pellets can be produced from agro-residues. The various technological applications of biomass torrefaction are also reviewed and the prospects in ensuring the continuous production of high-grade fuels are summarized.

与原始的未经处理的生物质相比，生物质材料的焙烧多年来受到了极大的关注，因为其能够生产具有更高的耐久性，出色的可磨性，更高的堆积密度和热值以及更高的能量密度的高级固体生物燃料材料。这是一种在惰性气氛下的温和热解处理技术，可以通过消除氧气，减少水分含量和改变化学成分来改善原始生物质的化学和物理性质。当原始生物质在默认氧气或N _2中温和地热解时在中等温度的大气中，可以显着增强原始生物质的性能，包括低热值，氢碳比，吸湿性和可磨性。在这篇综述中，分析和讨论了包括湿法，干法和离子液体辅助法在内的不同烘焙工艺的运行机理。更重要的是，详细讨论了用于商业化目的的反应器设计，反应动力学和机理，经济性以及生物质焙烧的可持续性。由于可以从农业残渣生产经过焙烧的基于农业残渣的颗粒，因此该综述扩展到了农业残渣生物质的焙烧。还综述了生物质焙烧的各种技术应用，并总结了确保连续生产高级燃料的前景。