Carbon emission to the environment is now recognised as a major contribution to the climate change imbroglio. The introduction of carbon tax or implementation of an emissions trading scheme by different national governments is now considered a reality in order to mitigate the long-term adverse effects of the carbon pollution and to encourage the industrial sector to move toward green process technologies. Steam reforming of hydrocarbons is the most important route for the commercial production of hydrogen (a clean fuel) but it is also accompanied CO2 (an undesirable greenhouse gas, GHG) emission. Around 7 tons of CO2 are produced and emitted per ton of produced H2. Thus, the recycling and reuse of CO2 for the process benefits may result in a significant improvement in the process efficiency as well as the environment. It is in this respect that the utilisation of CO2 as a carbon gasifying agent for the steam reformer becomes attractive since carbon deposition is a principal cause for loss in online catalyst (Ni-based systems) performance. Specifically, the present technology deals with the periodic forcing of the steam reformer with CO2 to improve both catalyst activity and longevity. Experiments were carried out over Co-Ni/Al2O3 catalyst in a fluidized bed reactor. Cycle period, τ, was varied between 10 to 60 mins at 5 different cycle symmetry, s (0.1≤ s ≤ 0.9). Both H2 and CO formation rates were higher than that attainable under steady-state operation at all periods investigated. In particular, the time-average H2:CO ratio was lower (<3.0) than the steady-state equivalent for the pure propane steam reforming (14.0) although it increased monotonically with cycle split. Composition cycling with CO2 also improved catalyst stability and longevity compared to steady-state performance at the cycle periods examined. This strategic reactor operation is therefore a potentially useful key to green process engineering in the overall petrochemical plant design to effect greenhouse gas emission reduction.
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机译：现在，环境的碳排放被认为是对气候变化揭幕境内的主要贡献。通过不同国家政府的碳税或实施排放交易计划的实施现在是为了减轻碳污染的长期不利影响，并鼓励工业部门走向绿色工艺技术的现实。碳氢化合物的蒸汽重整是氢气生产的最重要的途径（清洁燃料），但它也是CO2（不希望的温室气体，温室气体）发射。产生大约7吨二氧化碳并每吨产生的H 2发出。因此，对过程益处的CO2的回收和重用可能导致过程效率以及环境的显着改善。在这方面，在蒸汽重整器的碳气化剂的情况下，CO 2的利用变得有吸引力，因为碳沉积是在线催化剂（基于NI基系统）性能的主要原因。具体而言，本技术涉及通过CO2的蒸汽重整器的周期性强制，以改善催化剂活性和寿命。在流化床反应器中通过CO-Ni / Al 2 O 3催化剂进行实验。循环周期τ，在5个不同的循环对称下在10至60分钟之间变化（0.1≤s≤0.9）。 H2和CO形成率均高于调查的所有时期在稳态操作下可达到的速率。特别地，时间平均H 2：共比较低（<3.0），而纯丙烷蒸汽重整（14.0）的稳态等效于稳态等效于循环分裂单调增加。与CO 2循环的组合物还改善了催化剂稳定性和寿命，与在检查周期的循环期间的稳态性能相比。因此，这种战略反应堆操作是整体石化厂设计中绿色工艺工程的潜在有用的关键，以实现温室气体排放减少。
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