基于35kW等离子体炬典型生物质气化处置及多工况影响研究

Plasma Gasification of Biomass via 35kW Plasma Arc Torch System under Multi-conditions

等离子体热处理技术用于煤/生物质等固体燃料的气化转化具有能量密度高、反应速率快的优势,研发及应用前景广阔。本研究基于35 kW级直流非转移弧氮气等离子体炬搭建了一套固体燃料等离子体气化研究实验平台,以大米为厨余垃圾生物质典型组分,开展了一系列多工况条件下的等离子体气化反应实验,得出以下结论:等离子体炬的运行输出功率需与物料投入速率进行匹配,本研究表明单位热值的物料配合0.26倍能量的等离子体功率输入可达到最佳气化工况;等离子气化效率的提高与颗粒在等离子射流中的停留时间密切相关,物料颗粒粒径的大小需尽可能的保证停留时间的延长;等离子气化反应在过量空气系数约为0.1时达到最佳,低于传统气化工艺参数0.3;一定的水分有助于等离子气化反应的进行,本研究中最佳含水率为8.4%;等离子气化过程物料中加入5%的K2CO3盐有利于促进气化反应进行,同时降低气化残渣的石墨化程度;本研究最佳工况所实现的冷煤气效率为30.6%,仍需对系统进行优化以进一步提升气化效率。

Thermal plasma arc technology has the advantages of high heat source temperature and fast reaction rate.It is especially suitable for gasification of solid fuel as coal and biomass.However,development of such plasma technology and equipment is still insufficient in China.This work built a solid fuel plasma arc gasification system for biomass plasma gasification research.The plasma torch applied is a 35 kW power DC non transfer arc using nitrogen as energy carrier.Different sizes of rice grains were prepared and delivered into the thermal destruction system as the represent of kitchen waste biomass.A series of plasma gasification experiments was carried out and draw conclusions as follows:the output power of the plasma arc should be adjusted to match the input of the fuel energy and the best ratio of plasma arc torch output power to fuel energy input is 0.26;the residence time has strong influence on the efficiency of plasma arc gasification and the grain size of the biomass input into the reactor should be well controled to make sure the residence time of the grain in the reactor as long as possible;the best excess air ratio for plasma arc gasification measured in this study is 0.1 which is lower than the conventional gasification value of 0.3;the best water content of the feedstock input into the reactor for plasma arc gasification is 8.4%in this study;addition of 5%of K2CO3 as catalyst is appropriate for plasma arc gasification;the highest cold gas efficiency achieved in this study is 30.6%,indicating the necessity of further improvement of the plasma gasification system.