电源参数和气体组分对低温等离子体转化煤层甲烷的影响  

Effects of power supply parameters and gas composition on transformation of coal bed methane by low-temperature plasma

作　　者：朱丽华 张悦 田瑶瑶 徐锋 ZHU Lihua;ZHANG Yue;TIAN Yaoyao;XU Feng(School of Safety Engineering,Heilongjiang University of Science and Technology,Harbin150022,China)

机构地区：[1]黑龙江科技大学安全工程学院,黑龙江哈尔滨150022

出　　处：《洁净煤技术》2022年第5期81-86,共6页Clean Coal Technology

基　　金：国家自然科学基金资助项目(51874126)。

摘　　要：低温等离子体技术是实现CH_(4)固碳、减排的有效手段。然而,针对煤层CH_(4)的研究尚不深入。为探究低温等离子体转化煤层CH_(4)的影响因素及作用规律,构建了CH_(4)-N_(2)-O_(2)-H_(2)O试验体系,以刚玉为放电介质、螺纹状不锈钢棒为高压电极、钢丝网为低压电极,在1 mm放电间隙、长度200 mm的放电区域条件下,研究了输入电压、放电频率、CH_(4)体积分数对CH_(4)转化及产物生成的影响,并基于反应过程中活性物种发射光谱原位诊断,分析了主要产物的生成路径。结果表明,试验主要生成物为H_(2)、CO、CO_(2)、CH_(3)OH及C_(2)H_(4)、C_(2)H_(6)等C_(2)烃,且CH_(4)转化及产物分布受输入电压、放电频率和CH_(4)体积分数的影响,其原因为输入电压改变了DBD(介质阻挡放电)系统的注入能量及能量损耗,放电频率改变了反应器内流光放电的数量,CH_(4)体积分数改变了反应氧化环境;在试验研究范围内,较适宜的电源参数为输入电压75 V、放电频率9.8 kHz;以CH_(3)OH产率为考察指标时,较适宜的CH_(4)体积分数为35.4%;等离子体反应过程中产生CH_(3)·、CH_(2)·、CH·、C·、O·、OH·、H_(γ)、H_(β)、H_(2)和H_(α)等活性粒子,这些活性粒子与稳态分子作用,以及活性粒子之间相互作用生成产物分子。研究结果对深入研究煤层CH_(4)低温等离子体活化转化的工艺条件及反应机理具有重要意义。Low temperature plasma technology is an effective means to achieve carbon sequestration and emission reduction of methane.However,the research on coal bed methane has not yet been carried out in-depth.To explore the influencing factors and action rules of transformation of coal bed methane by low-temperature plasma,the CH_(4)-N_(2)-O_(2)-H_(2)O experimental system was constructed with corundum as discharge medium,threaded stainless steel rod as high pressure electrode,wire mesh as low pressure electrode.The influence of input voltage,discharge frequency,methane volume percentage on transformation of methane and product formation were investigated under the conditions of a 1 mm discharge gap and a discharge area of 200 mm in length.And based on the in situ diagnosis of the emission spectra of the active species during the reaction,the pathways of the main products were analyzed.The results show that the main products are hydrogen,carbon monoxide,carbon dioxide,methanol,ethylene,ethane and other C_(2) hydrocarbons.The methane transformation and product formation are affected by the input voltage,discharge frequency and CH_(4) volume fraction,because the input voltage changes the injection energy and energy loss of DBD system,discharge frequency changes the amount of streamer discharge in the reactor and volume percentage of methane changes the oxidation environment.In the range of experimental research,the optimal conditions are input voltage 75 V,discharge frequency 9.8 kHz;the optimal volume percentage of methane is 35.4% when the yield of methanol is used as the index.Active particles such as CH_(3)·,CH_(2)·,CH·,C·,O·,OH·,H_(γ),H_(β),H_(2) and H_(α) are generated during plasma reaction.These active particles interact with steady-state molecules and interact with each other to form product molecules.The results are of great significance to further study the process conditions and reaction mechanism of low-temperature plasma activation coal bed methane.

关 键 词：煤层甲烷 低温等离子体 输入电压 放电频率 CH_(4)转化率 

分 类 号：TQ519[化学工程] X936[环境科学与工程—安全科学]