Combustion research for chemical processing

This paper reviews the opportunities and challenges for combustion research directed towards the production of valuable chemicals. In the main, the production of heat and power are not considered here – the primary focus is on processes in which the desired products are the combustion products themselves, or products that are created by virtue of reaction in a combustion environment. The processes considered comprise three main classes: (1)Direct flame processes, including acetylene production, partial oxidation of methane, the Claus process for sulfur production, and material syntheses of nanocarbons and inorganics.(2)Catalytic partial oxidations that are conducted with the objective of avoiding complete combustion.(3)Chemical looping processes, based on chemical looping combustion in which a metallic oxide acts as an oxygen carrier, undergoing cyclical oxidation/reduction steps. Some of the processes being considered have been used in industry for many years. Despite, or perhaps because of, this there are opportunities for combustion research to lead to significant improvements in the operation of such processes. This point is illustrated via a detailed review of the science and technology of the catalytic combustion of ammonia over platinum that is the basis of the production of nitric acid and nitrate fertilisers on huge scale worldwide. Other processes remain at early stages of development, where opportunities for innovation are abundant. With many such opportunities involving catalysis, the status of detailed kinetic (microkinetic) modelling of catalytic process is also reviewed. This area may appear familiar to many combustion kinetic modellers but closer inspection reveals a wealth of chemical and computational complexity that transcends familiarity. The review in this area is necessarily superficial but does draw the links to traditional practice in the combustion community while also highlighting new techniques and approaches.