反应吸附强化模拟沼气蒸汽重整制氢的计算和实验研究

The calculation and experimental study of reactive sorption enhanced steam reforming of modeled biogas for hydrogen production

文章对反应吸附强化模拟沼气-水蒸气重整制氢技术(Re SER-Biogas)进行了热力学计算和实验研究。首先,建立甲烷蒸汽重整反应耦合氧化钙与二氧化碳反应的制氢反应模型,对CO2和CH4体积比(α)分别为0.25,0.43和0.67的模拟沼气进行改变CO2移除率(ζ)、反应温度(T)、水碳摩尔比(β)对甲烷转化率和氢气浓度影响规律的模拟计算。计算结果表明,提高ζ,T和β值能有效强化重整反应,当P=0.1 MPa,ζ=0.95,T=600℃,β=4时,甲烷转化率可达94%,产物中氢气的浓度可达96%。其次,采用镍系催化剂与纳米Ca O基CO2吸附剂,在固定床反应器中进行模拟沼气Re SER-Biogas制氢实验,改变T,β以及α值得到不同反应条件下的甲烷转化率与产品氢气浓度,从实验层面上验证模拟计算结果和反应条件影响规律的可靠性。实验结果表明,在P=0.1 MPa,ζ=0.95,T=600℃,β=4和α=0.43的实验条件下,产物中氢气的浓度高达93%,CO的浓度低至0.32%。和传统无吸附强化的沼气蒸汽重整制氢工艺相比,Re SER-Biogas技术能够在更低的温度条件下直接制取低CO浓度的高纯氢气产品,对开发高效,节能的沼气制氢新技术具有重要的实际意义。

Based on thermodynamic calculation and experimental research, the reaction characteristics of reactive sorption enhanced steam reforming of modeled biogas for hydrogen production（Re SER-Biogas） have been studied in this paper. First, the hydrogen production model was established where the methane steam reforming reaction was coupled with the calcium oxide and carbon dioxide reaction. The influence of some reaction conditions such as CO2 removal ratio（ζ）,reaction temperature（T）, the molar ratio of steam to methane（β） on the methane conversion and hydrogen purity was investigated according to the simulation results with volume ratio of carbon dioxide to methane in feed（α） 0.25,0.47 and 0.63, respectively. The calculation results showed that both the methane conversion and H2 purity could be increased effectively by the raise of ζ,T and β.When ζ=0.95, T=600 ℃, β=4, the methane conversion could reach 94% and H2 concentration could reach 96%. Experimental evaluation of Re SER-Biogas was studied by using the mixture of Ni catalyst and nano-CaO based CO2 adsorbent in a fixed bed reactor with modeled biogas. Based on the variation of T, β and α, the methane conversion and H2 concentration under different reaction conditions were obtained. The reliability of the simulation results and the laws of the reaction conditions influence were verified to be true. The experimental results indicated that the hydrogen content reached up to 93%with CO of 0.32% under the conditions of P=0.1 MPa, ζ=0.95, T=600 ℃, β=4 and α=0.43 which proved that the Re SER-Biogas could produce high-purity hydrogen with little CO in one reactor at lower temperature comparing with the conventional non adsorption enhanced biogas-steam reforming process. It is of great practical significance for the development of high-efficienty and energy-saving technologies for hydrogen production by biogas.