Assessment of CO2 capture options from various points in steam methane reforming for hydrogen production
Assessment of CO2 capture options from various points in steam methane reforming for hydrogen production
复制标题
评估蒸汽甲烷重整制氢过程中各个点的二氧化碳捕集方案
DOI：
10.1016/j.ijhydene.2014.09.161
复制
发表时间：
2014
影响因子：
7.2
通讯作者：
I. Dincer
中科院分区：
文献类型：
--
作者：
R. Soltani;M. Rosen;I. Dincer
甲烷蒸汽重整（SMR）是目前工业上主要的制氢工艺，但其CO2排放量高，平均约为7 kg CO2/kg H2，约占全球工业部门CO2排放量的3%。在此，报告了研究水蒸气与碳的比率（S/C）对来自工艺中的各个位置（即合成气流（位置1）、变压吸附器（PSA）尾气（位置2）和炉烟道气（位置3））的CO2捕集标准的影响的结果。在这项研究中考虑的CO2捕获标准是CO2分压，CO2浓度和CO2质量比相比，最终的废气流，这是炉烟道气。CO2捕获数（Ncc）被提议作为捕获有利性的度量，定义为上述三个捕获标准的乘积。每个标准都使用一个统一的权重。确定了在提供更好的捕获选项方面的最佳S/C比。由于合成气中CO2的分压较高，因此在变换装置后从合成气中脱除CO2是CO2捕集的最佳位置。然而，在该过程中产生的含有几乎50%的CO2的炉烟道气具有重要的环境意义。因此，富氧的炉进料的影响进行了研究，它被发现，这一措施改善了CO2捕获条件较低的S/C比。因此，对于2.5的S/C比，如果考虑烟道气流中完全存在CO2的较高加权因子，则从烟道气流中捕获CO2与其他两个位置具有竞争力。考虑到烟气脱碳，制氢速率与Ncc的比值随转化炉温度的升高而增大。
Steam methane reforming (SMR) is currently the main hydrogen production process in industry, but it has high emissions of CO2, at almost 7 kg CO2/kg H2on average, and is responsible for about 3% of global industrial sector CO2emissions. Here, the results are reported of an investigation of the effect of steam-to-carbon ratio (S/C) on CO2capture criteria from various locations in the process, i.e. synthesis gas stream (location 1), pressure swing adsorber (PSA) tail gas (location 2), and furnace flue gases (location 3). The CO2capture criteria considered in this study are CO2partial pressure, CO2concentration, and CO2mass ratio compared to the final exhaust stream, which is furnace flue gases. The CO2capture number (Ncc) is proposed as measure of capture favourability, defined as the product of the three above capture criteria. A weighting of unity is used for each criterion. The best S/C ratio, in terms of providing better capture option, is determined. CO2removal from synthesis gas after the shift unit is found to be the best location for CO2capture due to its high partial pressure of CO2. However, furnace flue gases, containing almost 50% of the CO2in produced in the process, are of great significance environmentally. Consequently, the effects of oxygen enrichment of the furnace feed are investigated, and it is found that this measure improves the CO2capture conditions for lower S/C ratios. Consequently, for an S/C ratio of 2.5, CO2capture from a flue gas stream is competitive with two other locations provided higher weighting factors are considered for the full presence of CO2in the flue gases stream. Considering carbon removal from flue gases, the ratio of hydrogen production rate andNccincreases with rising reformer temperature.