With the population and standard of living ever on the rise the Earth’s environment is under considerable strain as a result of increasing energy usage. Emissions are escalating and resources are at levels of depletion never before seen. Sustainable development is the only satisfactory answer to these problems, but it would seem that such a solution is not immediately available and that progression will be achieved by incremental upgrades to existing technology. Coal gasification, in which coal is converted to low energy syngas, is one of these transitional energy technologies which are becoming ever more popular. Its increasing popularity is well understood when it is considered that gasification offers an environmentally acceptable fuel whilst relying on the substantial coal reserves as a long term feedstock. The issues and implications of gasification were explored in this thesis, along with an overview of processes enabling the use of syngas for the production of value-added chemicals, liquid fuels and electrical power.
While there is much literature on the topic of gasification and its technical details there is relatively little that performs a holistic analysis of the topic. The approach of this thesis then was to analyse existing data to determine optimum combinations of coal feedstock, gasifier technology, and end-use process design. The analysis was based on the temperature and the composition of key syngas components, and a method of ranking the combinations was established which largely agrees with existing information. It was found that fixed bed reactors seem to offer the highest degree of flexibility, operating on most coal types and producing syngas capable of efficient use with a variety of processes.
It is hoped the analysis in this thesis can be progressed to a higher level, so that a conclusive model can be established which takes into account pressure and cost. Such a model would be able to endorse the findings of this thesis, and would be most useful in indicating the direction of development of proposed gasification operations.