(61c) Clean Coal Gasification Applications

The biggest drawbacks for utilizing coal are that it is solid, which makes its recovery as well as transportation rather complicated and applications limited (power generation mostly), and its combustion emits more pollutants such as sulfur (acid rain), heavy metals (mercury), and CO₂ (greenhouse gas) compared to conventional fuels such as natural gas and petroleum. However, recent advancements in clean coal technologies have made coal more competitive with conventional fuels in terms of emissions and economics for some applications.

The core of the clean coal technologies is coal gasification that allows pollutants to be removed prior to potential downstream applications, which currently include power generation, chemicals (methanol, ammonia, etc.) manufacture, Fischer-Tropsch synthesis, and substituted natural gas production. Many coal gasification technologies were developed in the last three decades. Some of them have been commercialized for over twenty years and have been continuously improved to offer high thermal efficiency and low waste effluents that made clean coal a viable substituted feedstock for the above applications.

The purpose of this paper is to evaluate alternate coal gasification technologies based on different end product applications. The evaluation is based on the current state of art coal gasification technologies that include, but not limited to, dry and slurry feed entrained flow processes. The advantages and disadvantages of each representative gasification technology will be discussed for the following applications: power generation, methanol production, ammonia production, substituted natural gas, and Fischer-Tropsch synthesis.