Gasification history

Building large commercial coal gasification combined cycle units could be difficult based on the history traditional power generators have had with simpler chemical processes. Sequesting the C02 can be another technological challenge. 

Finally, it is of interest, not only to the student of industrial archelogical history, but also to the modern technologist, to refer to coal gasification. A few decades ago the gasification of coal provided a means of supplying communities with coal gas, a mixture of hydrogen, methane and carbon monoxide, which could be ignited in burners and used as a domestic or industrial source of heat. With the discovery of natural gas... 

During World War II in Germany, automobiles were fueled by the gases produced from thermal decomposition of wood and research is ongoing today on the more efficient gasification of wood. Destructive distillation has been used throughout most recorded history to obtain turpentine from pinewood, as discussed later in the chapter. 

A computer model has been developed to provide numerical simulations of fluidized bed coal gasification reactors and to yield detailed descriptions, in space and time, of the coupled chemistry, particle dynamics and gas flows within the reactor vessels. Time histories and spatial distributions of the important process variables are explicitly described by the model. With this simulation one is able to predict the formation and rise of gas bubbles, the transient and quasi-steady temperature and gas composition, and the conversion of carbon throughout the reactor. 

Mineral impurities in coal are known to be primary contributors to the slagging and fouling of utility boilers, fly ash and bottom ash production as well as atmospheric pollution. They also produce undesirable effects in some parts of hydrogenation processes such as liquifaction and gasification (1,2,3). Despite a long history of investigation prompted by these observations, many questions remain unanswered. 

After the devolatilization and rapid-rate methane formation stages are completed, char gasification occurs at a relatively slow rate various models to describe the gasification kinetics of this material for various limited ranges of conditions have been proposed. The differential rates of reaction of devolatilized coal chars are a function of temperature, pressure, gas composition, carbon conversion, and prior history. 

Acid Gas Components. The oil and gas industries have a long history of effectively removing and processing carbon dioxide, hydrogen sulfide, and carbonyl sulfide, (collectively termed acid gases because they are acidic) from fuel gas streams. It is common to remove H2S and CO2 from raw natural gas before the gas enters the natural gas pipeline system. In coal gasification, a portion of the feed coal converts to CO2. 

History. Public Service of Indiana (PSI) is a major electric utility located in the state of Indiana. PSI is severely impacted by the SO2 reduction provisions of the Clean Air Act Amendment (CAAA) of 1990 due to it s large use of local high sulfur Indiana coals in older coal-fired units with no existing SO controls. However, there are special provisions in the CAAA for coal gasification repowerin. These provisions are discussed in detail in the Environmental Aspects, Section 4, of this report. Briefly, coal gasification repowering extends the Phase I SO2 emission allowances to the end of 1999 for the specific units repowered. The much lower Phase II allowances do not become effective until the end of 2003 for the specific units repowered. 

Commercial coal gasification processes are those that have a long history of commercial operation and are currently available to an electric utility for the routine production of fuel gas without further commercial-scale testing or demonstration except when testing specific coals. This category includes four gasification processes or technologies ... 

If coal is intended to serve as fuel for industrial gasification processes, it is smart to borrow know-how for coal characterization from combustion research because of its long and comprehensive history. Hence, well-known analysis methods and classification schemes will appear, which must be always reviewed in the light of gasification conditions that differ from combustion in terms of oxidant (oxygen and steam instead of air), operation pressure (20-100 bar), and overall reducing atmospheres (products are CO and H2 instead of CO2, H2O). 

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