Joint UK / China Hydrogen production network

全球变暖加剧带来的威胁日益严重，加上两国需要确保能源供应，因此提出了中英专家合作的建议。从化石燃料生产能源的清洁技术。该提案的首要主题是通过一些热化学路线从煤中生产清洁能源/H2，其中CO2被分离并准备封存。我们将研究两种形式的先进化学循环，它们允许从化石燃料中生产清洁的氢气，而不会（与现有技术不同）与捕获二氧化碳相关的大量能源损失。这些过程处于早期发展阶段，需要对概念的基础科学进行研究，以及如何从实验室扩大这些过程。这两种类型的化学循环都使用固体反应物，它们要么充当CO2受体，要么充当氧载体。1.使用煅烧-碳酸化循环的先进气化工艺：最初的ZECA工艺旨在从煤中产生氢气，首先将煤加氢气化为甲烷，然后转化为合成气，然后转化为H2。使用氧化钙进行变换反应以除去CO2并将水煤气变换反应的平衡移动到H2。首先将甲烷改革为合成气的需要面临煤中硫的潜在问题，煤中硫将以H2S形式污染甲烷，并使重整催化剂失活。在这里，我们将研究结合重整器和变换反应器，以及H2S对钙循环剂的影响，钙循环剂必须在CaO和CaCO 3之间重复循环。需要探索一系列燃料的加氢气化，因为该过程的效率将取决于将固体燃料完全转化为甲烷的能力。在中试规模上，将在循环流化床中研究强化水煤气变换工艺的连续操作。使用基于氧化铁的氧化还原循环制氢：在化学链燃烧中，燃料可以与金属氧化物（而不是空气）燃烧以产生纯CO2流。为了发电，还原的氧化物可以用空气再氧化以释放热量。一些金属和氧化物（如铁）可以用蒸汽部分氧化，产生非常纯的H2。Fe 2 O3氧化物可以用合成气还原为FeO或Fe;然后Fe和FeO可以用蒸汽氧化，得到Fe 3 O 4和氢气。该循环可以通过用空气氧化Fe 3 O 4来完成。在这里，我们将调查在实验室规模，并在中试规模，使用流化床和移动床反应器的组合，这一过程的连续操作。合成气必须由煤产生，并且将含有焦油和H2S。我们将研究挥发性材料和硫对铁基载体的影响，即金属氧化物可以燃烧挥发物的程度，以及氧化物是否被硫钝化。这些金属氧化物和焦油裂解催化剂在气化过程中的使用也将进行研究。钙基CO2受体和金属氧化物基氧载体都必须经历许多操作循环。天然材料通常会迅速降解。可以生产具有更好特性的人造颗粒。然而，颗粒的行为是物理结构和添加剂/污染物的存在的非常强的函数。我们将研究这些材料的配方如何影响它们的物理结构，以及这将对许多循环的反应性产生的影响。

The increasing threat posed by enhanced global warming, together with the requirement to secure energy supplies for both countries have led to this proposal for a collaboration of experts between China and the U.K. in clean technologies for energy production from fossil fuels. The overarching theme of the proposal is the production of clean energy/H2 from coal, via a number of thermochemical routes with the CO2 separated and ready for sequestration. We will investigate two forms of advanced chemical cycles which allow clean hydrogen to be produced from fossil fuels, without (unlike with current technology) a large energy penalty associated with capturing the CO2. These processes are at an early stage of development with research required on the underlying science of the concepts, as well as how these processes can be scaled up from the laboratory. Both types of chemical cycle make use of solid reactants which either act as CO2 acceptors or oxygen carriers. 1. Advanced gasification processes using the calcination-carbonation cycle: The original ZECA process aimed to generate hydrogen from coal, by first hydrogasifying the coal to methane, then reforming to syngas, before shifting to H2. The shift reaction was to be performed using calcium oxide to remove the CO2 and move the equilibrium of the water-gas shift reaction over to H2. The need to first reform the methane in to syngas faced potential problems with the sulphur in the coal which will contaminate the methane as H2S, and deactivate reforming catalysts. Here we will investigate combining the reformer and shift reactors, and the effect of H2S on the calcium looping agent, which must be repeatedly cycled between CaO and CaCO3. The hydrogasification of a spectrum of fuels needs to be explored, since the efficiency of this process will depend on the ability to completely convert the solid fuel into methane. At a pilot scale the continuous operation of enhanced water-gas shift process will be investigated, in a circulating fluidised bed.2. Hydrogen production using the iron-oxide based redox cycle: In chemical looping combustion, a fuel can be burned with a metal oxide (rather than air) to produce a stream of pure CO2. For power generation, the reduced oxide can be reoxidised with air to release heat. Some metals and oxides (e.g. iron) can be partially oxidised with steam to produce very pure H2. Fe2O3 oxide can be reduced to FeO or Fe using syngas; Fe and FeO can then be oxidised with steam giving Fe3O4 and hydrogen. The cycle can be completed by oxidising the Fe3O4 with air. Here we will investigate the continuous operation of this process on a laboratory scale, and on a pilot scale, using a combination of fluidised and moving bed reactors. The syngas must be generated from coal and will contain tars and H2S. We will investigate the affect of volatile material and sulphur on the iron based carrier, i.e. the extent to which the metal oxides can combust the volatiles, and whether the oxides are deactivated by sulphur. The use of these metal oxides ad tar cracking catalysts during gasification will also be investigated. Both the calcium based CO2 acceptors and the metal oxide based oxygen carriers must undergo many cycles of operation. Natural materials will often rapidly degrade. Artificial particles can be produced which have better characteristics. However, the behaviour of the particles is a very strong function of the physical structure, and the presence of additives/contaminants. We will investigate how the formulation of these materials affects their physical structures and the impact this will have on the reactivity over many cycles.