Other Clean Coal Technologies
Gasification is crucial to a number of other efforts under way to develop plants that produce clean energy from coal:
The Department of Energy is using coal gasification as the basis of its effort to build an emissions-free power plant. As envisioned, its so-called FutureGen project would produce electricity and hydrogen from coal and capture the carbon dioxide that would be generated in the process.
The carbon dioxide would be injected thousands of feet underground on site. The Energy Department's goal is to have an experimental facility operational by 2012. The hydrogen would be used to create electricity. Later on, the same project would be used to create hydrogen to fuel cars and other vehicles.
Coal to Liquid Fuel
Rentech Inc., based in Denver, is one of the companies trying to turn coal into low-polluting liquid fuel. Their technology is based on the Fischer-Tropsch process, named after the German researchers, Franz Fischer and Hans Tropsch. They invented the process in the 1920s, when Germany lacked petroleum reserves but had plenty of coal.
With the Fischer-Tropsch process, you start with coal or another carbon-based resource and put it in a gasifier. You take the resulting gas, known as syngas -- a mixture of hydrogen and carbon monoxide -- and put it into another reactor. In the reactor, the gases are combined with a solid catalyst such as iron or cobalt. A chemical reaction takes place to convert them into hydrocarbons, which later cool to form liquid fuel.
The process was used by Nazi Germany and Japan during World War II. When apartheid was the law of the land in South Africa, the country was subject to an international petroleum embargo. To compensate, South Africa developed Fischer-Tropsch operations, which are still in use today.
Rentech's process uses an iron-based catalyst, which the company says improves on existing technology. According to Rentech's Web site, its process results in fuel that burns very cleanly because it is low in sulfur, particulates and aromatics. It can be adapted to be used for a variety of purposes, including jet fuel. Rentech's Web site states that the company is currently building a small pilot plant in Commerce City, Co., outside of Denver.
Several other companies and the states of Pennsylvania and Montana are engaged in their own projects to create liquid fuel out of coal.
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