旋转弧放电等离子体重整乙醇制氢

Hydrogen production from ethanol reforming using rotating arc discharge plasmas

关键词:  制氢  重整  旋转弧  等离子体  乙醇

Key words:  hydrogen production  reforming  rotating arc  plasma  ethanol

摘要:

目的 为了抑制炭沉积、优化操作条件和提高产氢效率,基于绿色制氢和现场制氢的理念,研究了一种用等离子体重整制氢的新型制氢技术,优化设计了一套等离子体气相重整乙醇制氢装置。方法 以空气作为工作气体,研究了氧醇物质的量比(以下简称氧醇比)、乙醇流量、放电电压和放电间距对重整结果的影响。结果 氧醇物质的量比过大或者过小都不利于重整。当氧醇比为0.9时,乙醇转化率可以达到100%,H₂选择性为41.21%；氧醇比为1.2时,H₂产率和H₂选择性达到最大,分别为1 200.26 L/h和50.01%。适当提高乙醇流速可提高乙醇转化率和能量效率,但是会降低H₂选择性和H₂收率。提高放电电压对重整效果具有积极作用。在放电电压为1.8 kV时,H₂最大能量产率为687.94 L/kW·h。适当增大放电间距能够提高重整效果,但是不能过大,否则会导致电弧不稳定。结论 该套重整装置在抑制积炭形成和提高制氢效率上表现出了良好的效果。最佳实验条件为氧醇比1.1、乙醇流量33.7~42.1 mL/min、放电电压1.8 kV、放电间距2.5 mm。重整的气相产物为H₂、CO、CO₂、CH₄、C₂H₂、C₂H₄、C₂H₆、C₃H₆、C₃H₈。其中,γ-C₂或更高碳氢化合物的含量相当低。 

Abstract:

Objective In order to suppress carbon deposition, optimize operating conditions and increase the efficiency of hydrogen production, based on the concept of green hydrogen production and on-site hydrogen production, a new hydrogen production technology by plasma reforming is researched, and a set of equipment for ethanol reforming using rerotating arc plasmas had been optimized. Methods Air is used as the working gas to investigate the effects of oxygen to ethanol molar ratio (n(O₂)/n(Et)), ethanol flow rate, discharge voltage and discharge distance on the reforming results. Results Too large or too small n(O₂)/n(Et) is not conducive to reforming. When the n(O₂)/n(Et) is 0.9, the ethanol conversion rate can reach 100%, and the hydrogen selectivity is 41.21%. When the n(O₂)/n(Et) is 1.2, the hydrogen yield and hydrogen selectivity achieve maximum values of 1 200.26 L/h and 50.01%, respectively. Properly increasing the ethanol flow rate can increase the ethanol conversion rate and energy efficiency, but will reduce the hydrogen selectivity and hydrogen yield. The discharge voltage has an obvious positive effect on the reforming effect. When the discharge voltage is 1.8 kV, the maximum energy yield of hydrogen is 687.94 L/kW·h. Properly increasing the discharge distance can improve the reforming effect, but it should not be too large, otherwise the arc will be unstable. Conclusion sThis set of reforming equipment has shown a good effect in suppressing the formation of deposited carbon and the efficiency of hydrogen production. The best experimental conditions are the n(O₂)/n(Et) of 1.1, the ethanol flow rate of 33.7 mL/min, the discharge voltage of 1.8 kV, and the discharge distance of 2.5 mm. The gas phase products of reforming are H₂, CO, CO₂, CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₆, and C₃H₈. Among them, the content of C₂ or higher hydrocarbons is lower.