Value-added fuels from the supercritical water processing of wastes

聚合物废物包括废塑料、轮胎和生物质，每一种都是目前被浪费的大量宝贵资源。这类废物的可持续管理是英国、欧洲和全世界的一个重大环境和资源管理问题。对气候变化的担忧也激起了人们对用替代来源生产非化石燃料的极大兴趣。超临界水是一种独特的反应环境，在这种环境中，在超临界条件下发现的单一致密相中会产生高反应速率。超临界水是指高于临界点(温度374.8摄氏度，压力22.1兆帕)的水，水以单一、致密的流体相存在，从而将传质阻力降至最低，并为快速反应提供环境。在这种条件下，碳氢化合物废物很容易溶解，通过控制工艺条件和使用合适的催化剂，可以获得更高价值的液体和气态燃料。这项工作的目的是研究利用废塑料、轮胎和废生物质的超临界水液化来生产用作优质液体燃料的成品油。还研究了废物的超临界水气化产生的富氢气体。实验工作将使用实验室规模的全仪器化亚临界/超临界水反应堆，在一系列工艺条件下处理废塑料、轮胎和废生物质。将研究一系列亚临界和超临界水工艺条件，包括温度、压力、原料与水的比例，以及使用不同类型的均相和非均相催化剂，以最大限度地提高优质液体燃料或氢气的目标产品产量。将使用一套气相色谱仪器对产品的气体成分进行详细的分析。产品油将用高效液相色谱进行石油分馏，并用气相色谱/质谱联用法进行分析。这种详细的分析将有助于开发催化机理，并了解与超临界水处理不同类型的废物有关的对液化和气化特性的影响。将设计和开发催化剂，以改善工艺和最终产品的性能。用扫描和透射电子显微镜、能量色散X射线能谱和X射线衍射仪对催化剂进行了详细的分析。英国致力于经济转型，以确保低碳可持续的未来和减少资源浪费。因此，迫切需要为废塑料、轮胎和废生物质等聚合物废物制定可持续的、能够确保发展安全的低碳未来和安全的能源供应的废物管理程序。因此，这项研究通过解决这些废物的废物管理问题而使英国受益，这些废物在英国以高吨位产生，以生产价值更高的优质液体燃料或富氢气体。

Polymeric wastes include, waste plastics, tires and biomass and each represent large amounts of valuable resources that are currently wasted. The sustainable management of such wastes is a major environmental and resource management issue in the UK, Europe and throughout the world. The concern around climate change has also created great interest in producing non-fossil fuels from alternative sources. Supercritical water is a unique reaction environment where high reaction rates are produced in the single dense phase found under supercritical conditions. Supercritical water is water above its critical point, (374.8 C temperature and 22.1 MPa pressure) where water exits as a single, dense fluid phase thus minimising mass transfer resistances and providing an environment for rapid reaction rates. Under such conditions, hydrocarbon wastes are easily solubilized and by manipulating the process conditions and with the use of suitable catalysts, higher value liquid and gaseous fuels can be obtained. The aims of this work are to investigate the use of supercritical water liquefaction of waste plastics, tyres and waste biomass to produce product oils for use as premium grade liquid fuels. Also to investigate the supercritical water gasification of the wastes to produce a hydrogen-rich gas. The experimental work will use a bench-scale fully instrumented sub-critical/supercritical water reactor to process the waste plastics, tyres and waste biomass over a range of process conditions. A range of sub-critical and supercritical water process conditions of temperature, pressure, feedstock:water ratio, and the use of different types of homogeneous and heterogeneous catalysts will be investigated to maximise the targeted product yield of either premium grade liquid fuels or hydrogen. Gas chromatography will be used to analyse the product gas composition in detail using a suite of gas chromatographs instruments. The product oils will be analysed by oil fractionation using HPLC and analysis of the fractions using combined gas chromatography/mass spectrometry. Such detailed analysis will aid the development of the catalytic mechanism and understand the effect on the liquefaction and gasification characteristics in relation to the supercritical water processing of the different types of waste. Catalysts will be designed and developed to improve the process and end-product properties. Detailed analysis of the catalysts will us scanning and transmission electron microscopy with energy dispersive X-ray spectrometry and X-ray diffraction. The UK is committed to transforming its economy to ensure a low carbon sustainable future and a reduction in the waste of resources. There is therefore an urgent need to develop waste management processes for polymeric wastes such as waste plastics, tires and waste biomass that are sustainable and can ensure the development of secure low carbon future and secure energy supply. This research thereby benefits the UK by solving a waste management problem for these wastes, that are generated in high tonnages in the UK, to produce higher value premium grade liquid fuels or hydrogen-rich gas.