Gasification was first utilized to convert coal into synthetic gas in the late 1700s to provide gas for the lighting and heating of homes in some parts of Europe. Today, modern gasifiers at more than 160 locations around the world are converting coal, petroleum coke, natural gas, oil, refinery residues or biomass into synthetic gas for the production of electrical power, substitute natural gas, hydrogen, steam, ammonia fertilizer, methanol, naptha, diesel, chemicals and other valuable products.

The gasification process heats and reacts carbonaceous fuels with oxygen and water to produce a low-to-medium heating value synthetic gas, typically with one-fourth to one-third of the energy content of natural gas. This synthetic gas primarily is composed of hydrogen and carbon monoxide, which can be used for fuel in boilers and combustion turbines and also can be further processed for use in chemical processes. In some gasification processes, as much as 95 percent of the energy in the original solid feedstocks is converted to useful chemical and thermal energy.

Integrated Gasification Combined Cycle (IGCC) is a gasification application to produce electrical power. There are three operational IGCC facilities in the United States and more than 12 elsewhere in the world.

Advantages
Gasification offers advantages in efficiency and environmental performance for both electrical power generation and industrial applications. The nature of the gasification process facilitates removal of criteria pollutants such as particulate, mercury and sulfur compounds from the synthetic gas prior to combustion or further processing, keeping these pollutants from being emitted to the environment.

Gasification is commonly used for chemical production, primarily fertilizers, in areas such as China that do not have plentiful natural gas supplies. It allows utilization of the more available indigenous coal to meet these needs. Gasification facilities also can process low value and opportunity fuels, such as petroleum coke and refinery residual oils, to produce higher grade energy and products in an environmentally superior manner.

IGCC for power applications consumes less water and creates less solid and liquid wastes than conventional coal-fired boiler applications, and is ideally used for baseload generation needs.

Gasification processes also facilitate the more efficient and less costly pre-combustion removal of carbon dioxide from the process streams, utilizing technologies that are commercially available today. This carbon dioxide stream has been shown to be effective for carbon dioxide-based enhanced oil recovery of residual oil reserves in mature reservoirs. These CO2 streams could also be captured for storage to reduce the greenhouse gas impact of coal.

Issues
Although the environmental benefits of gasification are well recognized, most installations to date have been located in geographic areas where natural gas is not readily available or have been partly funded through government incentives. Initial capital costs are higher than conventional technologies that utilize solid fuels for power generation, such as supercritical pulverized coal.

Industrial gasification to produce chemical products is not economic, while natural gas is inexpensive and readily available. There also are concerns about reliability because of early technical issues at some of the demonstration facilities, although these have been largely resolved in subsequent operations.