Biomass pyrolysis is the thermal decomposition of biomass occurring in the absence of oxygen. It is the fundamental chemical reaction that is the precursor of both the combustion and gasification processes and occurs naturally in the first two seconds. The products of biomass pyrolysis include biochar, bio-oil and gases including methane, hydrogen, carbon monoxide, and carbon dioxide.
当有机物在惰性气氛中加热时，热解过程包括同时和连续反应。在生物质中的有机成分在350℃〜550℃开始进行热分解，并在无空气/氧气时上升到700℃〜800℃。生物质中碳、氢、氧的化合物长链分解成较小的分子，热解条件下产生气体、可冷凝液体（焦油和油）和固体炭。这些的分解速度和程度取决于反应器的温度的工艺参数，生物质加热速率、压力、反应器结构以及原料等。The pyrolysis process consists of both simultaneous and successive reactions when organic material is heated in a non-reactive atmosphere. Thermal decomposition of organic components in biomass starts at 350 °C–550 °C and goes up to 700 °C–800 °C in the absence of air/oxygen. The long chains of carbon, hydrogen and oxygen compounds in biomass break down into smaller molecules in the form of gases, condensable vapours (tars and oils) and solid charcoal under pyrolysis conditions. Rate and extent of decomposition of each of these components depends on the process parameters of the reactor temperature, biomass heating rate, pressure, reactor configuration, feedstock etc热解产物取决于热环境和最终温度，在小于450℃的低温下，升温速率很慢时，主要产生生物质炭，而在大于800℃高温下，升温速率很快时，主要产生气体。在中间温度和相对较高的升温速率，主要产物为生物油。Depending on the thermal environment and the final temperature, pyrolysis will yield mainly biochar at low temperatures, less than 450 ℃, when the heating rate is quite slow, and mainly gases at high temperatures, greater than 800 ℃, with rapid heating rates. At an intermediate temperature and under relatively high heating rates, the main product is bio-oil.The essential features of a fast pyrolysis process are:Very high heating and heat transfer rates, which require a finely ground feed.Carefully controlled reaction temperature of around 500℃ in the vapour phase.Residence time of pyrolysis vapours in the reactor less than 1 secQuenching (rapid cooling) of the pyrolysis vapours to give the bio-oil product.热解可以在相对小规模和较远的地方进行，提高生物质资源的能量密度、降低运输和处理成本。传热是热解过程中的一个关键环节，吸热和充分传热必须满足过程的热需求。生物质热解为有机物转换成能源产品提供提供了一种灵活引人注目的方式，可用于生产热、点、化工产品等。
Pyrolysis can be performed at relatively small scale and at remote locations which enhance energy density of the biomass resource and reduce transport and handling costs. Heat transfer is a critical area in pyrolysis as the pyrolysis process is endothermic and sufficient heat transfer surface has to be provided to meet process heat needs. Biomass pyrolysis offers a flexible and attractive way of converting organic matter into energy products which can be successfully used for the production of heat, power and chemicals.广泛的生物质原料可用于热解过程中。热解过程非常注重原料的含水量，即10％左右水分含量。更高的水分含量的话，会产生高水量，在更低水分含量的话，会有只产生粉尘而不是油的风险。高水分的废物流，如污泥和肉类加工废料，需要在热解反应之前进行干燥。
A wide range of biomass feedstocks can be used in pyrolysis processes. The pyrolysis process is very dependent on the moisture content of the feedstock, which should be around 10%. At higher moisture contents, high levels of water are produced and at lower levels there is a risk that the process only produces dust instead of oil. High-moisture waste streams, such as sludge and meat processing wastes, require drying before subjecting to pyrolysis.