Kinetic Benefits of Small Particle Size for Fluid Bed or Transport Coal Gasification

Statement of the Problem There are many processes that can be used convert coal into fuels, chemicals and electrical power including direct combustion (power generation), gasification (chemicals, fuels and power) and direct liquefaction (fuels). Of all of these processes, only coal gasification has the potential to make fuels, chemicals and power along with the possibility for CO2 capture and sequestration. Unfortunately, coal gasification is expensive and to make the process economically viable generally requires very large, capital intensive plants to achieve economies of scale. As a result, small scale gasification for local/on-site uses (such as local power generation) is not economical. What is needed is a new gasification technology that is more economical at small scales, and can be part of a modular power/fuels/chemicals production facility. How it is Being Addressed Our goal is to solve this problem by developing a unique gasification reactor technology that takes advantage of the fact that small coal particles are more reactive than conventional pulverized coal. In our technology, the gasifier can be small enough that it can be economically constructed without using a refractory lining, thus reducing its cost and making the gasifier faster to start and stop as needed. What is Being Done in Phase I In Phase I, we will quantify the reactivity of two types of coal as a function of particle size using our stationary bubbling fluidized bed reactor system that uses a special heat transfer medium that keeps the coal particles in an isothermal environment. We will use statistically designed experiments to develop an empirical model of coal reactivity and correlate the results with detailed analysis of both the coal and the ash formed during gasification. We will then design, build and test a cold flow model of our novel gasification reactor and use the test results to design a high temperature, high pressure metal gasifier to be built and tested in Phase II. Commercial Applications Our gasifier design will be ideally suited for skid-mounted gasification units. In terms of skid mounted gasification units, the most appropriate use for such systems is probably on-site generation of electricity using a gas turbine or an internal combustion engine. Finally, this gasifier design would be ideally suited for use at mine-mouth or coal preparation locations. Key Words – Coal, gasification, micronized coal