Glossary of Terms

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ACID GAS REMOVAL

Acid Gas is natural gas or any other gas mixture that contains significant amounts of hydrogen sulfide (H2S), carbon dioxide (CO2) or similar contaminants. Before a raw natural gas containing hydrogen sulfide and/or carbon dioxide can be used, the raw gas must be treated to reduce those impurities to acceptable levels, commonly done by using an amine gas treating process. The removed H2S is most often subsequently converted to by-product elemental sulfur using the Claus process. This same process must be used on syngas produced by coal gasification.

Air separation plants produce nitrogen, oxygen, argon and other rare gases using air as its only raw material. The process is powered by electricity and a small amount of water.

Gasification is a process that converts carbonaceous materials, such as coal, petroleum or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and steam. The resulting gas mixture is called synthesis gas or syngas and is, itself, a fuel. This syngas is sometimes referred to as town gas due to its use to light street lights in the early 1900s. With a coal or biomass-to-Synthetic Natural Gas conversion efficiency ratio of approximately 72 percent, the gasification process is a very efficient process for the production of reliable energy at a reasonable price.

A standard unit of measurement used to denote both the amount of heat energy in fuels and the ability of appliances and air conditioning systems to produce heating or cooling. A BTU is the amount of heat required to increase the temperature of a pint of water (which weighs exactly 16 ounces) by one degree Fahrenheit. MMBTU is occasionally used as a standard unit of measurement for natural gas and provides a convenient basis for comparing the energy content of various grades of natural gas and other fuels. One cubic foot of natural gas produces approximately 1,000 BTUs, so 1,000 cu. ft. of gas is comparable to MMBTU, which is intended to represent a thousand BTUs.

Methane is a chemical compound with the molecular formula CH4. It is the simplest alkane and the principal component of natural gas. Methane's relative abundance and clean burning process makes it a very attractive fuel.

Produced by the gasification process, slag is vitrified (non-leachable, glass like) inorganic matter with metal based coal byproducts locked inside. Gasifier slag is typically sold as filler for roadbed construction or as a component for roofing materials. Ground granulated slag is also used in concrete in combination with Portland cement as part of blended cement. Concrete containing ground, granulated slag develops strength over a longer period, leading to reduced permeability and better durability properties.

Sulfur is a chemical element that has the symbol S and atomic number 16. Its commercial uses are primarily in fertilizers, but it is also widely used in gunpowder, matches, insecticides and fungicides.

This is a gas that has been upgraded to a quality similar to natural gas. Obtained from coal or biomass, synthetic natural gas is manufactured through thermal gasification of organic material or coal. The syngas, resulting from gasification, is upgraded in a secondary step to produce natural gas that is suitable for injection into the national gas pipeline grid. By upgrading the quality to that of natural gas, it becomes possible to distribute the gas to customers via the existing natural gas pipeline grid, and burned within existing appliances. Synthetic natural gas can be produced economically, making it an attractive means of supplying the United States with reliable gas energy. The existing gas pipeline network allows distribution of gas energy over vast distances at a minimal cost in energy. Existing pipeline networks allow gas to be sourced from remote markets that are rich in low-cost coal or biomass. The existing gas storage infrastructure allows the plant to continue to process coal into gas at the full utilization rate even during periods of weak demand, helping minimize capital costs per unit of gas produced.

Syngas is a mixture of carbon monoxide (CO) and hydrogen (H2) that is formed as result of gasification or other process. Raw syngas is gas containing impurities such as sulfur compounds. Clean syngas has all impurities removed.