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Dual mode plasma UV microreactor for ozonolysis and hydrogenation green chemistry

用于臭氧分解和加氢绿色化学的双模式等离子体紫外微反应器

基本信息

批准号：
EP/I027858/1
负责人：
William Zimmerman
金额：
$ 13万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FI027858%2F1
关键词：
Dual mode plasma UV microreactor

项目摘要

Ozone is a powerful oxidizing agent but is conventionally expensive to produce, requiring high voltage operation with high power draw, typically produced under vacuum with pure oxygen, cryogenically stored, and unspent, poorly mixed ozone is a hazard that requires expensive, dedicated plant room to destroy. Consequently, ozone is only used when there is no reasonable alternative.We have developed a method for producing ozone at room temperature, atmospheric pressure, from air feedstock, with low voltage operation, high yield, and low power consumption (approximately 1/10th the power draw of conventional plasma reactors with the same throughput), using plasma microreactors. In order to increase the volumetric flow rate, we have multiplexed the microreactors in a dosing lance that delivers the ozone directly into aqueous solution, with dispersal by microbubbles. We are developing this technology for use in the water sector, for applications in water purification and wastewater treatment, where energy efficiency in the production and dispersal of ozone is a strong driver. Our microbubble approach for dispersal should also improve dispersal rates by an order of magnitude, thus minimizing wastage and associated hazards - the level of dosing can be tuned so that all the ozone or intermediates in the production of ozone can be dissolved and consumed in reaction.Plasmolysis formation from steam has always been viewed as an expensive route to hydrogen production, with estimates of 50% efficiency with conventional plasma reactors, trailing behind electrolysis and about on par with thermochemical cycles. In laboratory trials with plasma microreactors, we generated hydrogen from steam with the same conditions as the ozone reaction: room temperature, atmospheric pressure, with low voltage operation,, and low power consumption. Given that it is impossible to achieve a tenfold energy efficiency savings over conventional plasmolysis, the logical conclusion is that some of the heat of reaction is drawn from the steam, and the remainder is the electricity draw. This suggests the potential for substantial energy savings wherever there is a source of waste steam or waste heat to raise steam.Of course, plasmolysis produces H2 and O2 simultaneously and with no space segregation, as in electrolysis. Hence there is a need to separate the products so as to use them separately. Microbubbles provide a sufficient separation due to the fact that hydrogen is practically insoluble in water - oxygen is 25-fold more soluble at room temperature. Hence microbubbles with a tall enough head of water will be practically stripped of oxygen, thus hydrogen rich when they burst at the gas-liquid interface upon rising through a column of water. Since aeration of many wastewaters is a desired processing step, there is every possibility that the hydrogen separation can be achieved while integrated with other processing operations on an industrial plant.With a cheap source of ozone for ozonolysis reactions and hydrogen for hydrogenation reactions, the dosing lance has the potential to yield co-products from biomass processing economically - precursors for bioplastics, nutraceuticals, fine chemicals and pharmaceuticals - from the waste products of agriculture, pulp and paper processing, algal biofuels and biodiesel production, for instance. Although currently petroleum production is highly profitable for the fuel, historically, the introduction of petrochemicals from the bottom of the barrel enormously enhanced the profitability of petrol refining. In order to make bioprocessing to biofuels profitable (and hence sustainable) a similar set of profitable co-products may be necessary. This proposal aims to construct the robust prototype for industrial scale processing of the dosing lance and assess its economic potential for producing co-products.

臭氧是一种强氧化剂，但传统上生产昂贵，需要高电压操作和高功率消耗，通常在真空下用纯氧生产，低温储存，未用过的、混合不良的臭氧是一种危险，需要昂贵的专用车间来破坏。因此，只有在没有合理的替代品时才使用臭氧。我们开发了一种使用等离子体微反应器在室温、大气压下从空气原料生产臭氧的方法，该方法具有低电压操作、高产率和低功耗（约为具有相同产量的传统等离子体反应器功率消耗的1/10）。为了增加体积流量，我们已经复用的微反应器中的定量喷枪，提供臭氧直接进入水溶液中，与分散的微气泡。我们正在开发用于水行业的技术，用于水净化和废水处理，其中臭氧生产和分散的能源效率是一个强大的驱动力。我们的微泡分散方法还应将分散速率提高一个数量级，从而最大限度地减少浪费和相关危害-可以调整剂量水平，以便所有臭氧或臭氧生产中的中间产物都可以溶解并在反应中消耗。从蒸汽中形成增塑剂一直被认为是一种昂贵的制氢途径，传统等离子体反应器的效率估计为50%，落后于电解，与热化学循环相当。在等离子体微反应器的实验室试验中，我们在与臭氧反应相同的条件下从蒸汽中产生氢气：室温，大气压，低电压操作，和低功耗。考虑到不可能实现比传统的塑化器节省十倍的能源效率，合乎逻辑的结论是，一部分反应热来自蒸汽，其余部分是电力消耗。这表明，只要有废蒸汽或废热的来源来产生蒸汽，就有可能大幅节省能源。当然，塑化同时产生H2和O2，并且没有空间隔离，就像电解一样。因此，需要将产品分开以便单独使用它们。由于氢气几乎不溶于水-氧气在室温下的溶解度是水的25倍，因此微泡提供了充分的分离。因此，具有足够高水头的微泡实际上将被剥离氧气，因此当它们在上升通过水柱时在气液界面处破裂时富含氢气。由于许多废水的曝气是期望的处理步骤，因此完全有可能在与工业装置上的其他处理操作集成的同时实现氢气分离。利用用于臭氧分解反应的廉价臭氧源和用于氢化反应的氢气源，定量喷枪具有经济地从生物质处理中产生副产品的潜力-生物塑料、营养保健品的前体，精细化学品和药品-例如，来自农业、纸浆和纸张加工、藻类生物燃料和生物柴油生产的废物。虽然目前石油生产的燃料利润很高，但从历史上看，从桶底引入石化产品极大地提高了汽油精炼的利润率。为了使生物燃料的生物加工有利可图（因此是可持续的），可能需要一套类似的有利可图的副产品。该提案旨在构建用于工业规模处理的定量喷枪的稳健原型，并评估其生产副产品的经济潜力。