Energy Technologies

Gasification

What Is Gasification?

Gasification is a process that uses heat, pressure, and steam to convert materials directly into gas. It has been in use for many years, and involves breaking down complex organic molecules and carbon, in both liquid and solid state, into simple gases.

Gasification is a thermal process but it is designed to produce a syn-gas as the main product, rather than the flue gas produced by a similar thermal process, combustion (i.e. incineration). The syn-gas consists largely of carbon dioxide and H2 and contains a large percentage of the inherent chemical energy of the input fuel.

Rather than treating waste in an oxygen-free environment, as is the case when waste is pyrolysed, gasification occurs in the presence of a controlled amount of air that is sufficient to allow only partial combustion of a small amount of the fuel input. The thermodynamics of the process are therefore very different from pyrolysis. Oxygen in the air aids the breakdown of the heavy organic compounds in the waste, thereby optimizing the yield of syn-gas. Most of the gases produced are flammable and are therefore generally used as fuel in processes or applications where such gases are required. When mixed with air, syn-gas can be used in gasoline or diesel engines with minimal modifications required to the engine.


Our gasification technologies differ in several technical aspects but rely on four key engineering factors:

• the gasification reactor atmosphere (level of oxygen or air content present during the process)
• reactor design
• internal/external heating ratio
• operating temperature

Typical raw materials used are coal, petroleum-based materials and organic materials. The feedstock is prepared and fed, in either dry or slurried form, into a sealed reactor chamber called a gasifier, where it is subjected to high heat, pressure, and either an oxygen-rich or oxygen-starved environment. Most commercial gasification technologies do not use oxygen, but all require an energy source to generate heat which starts the process.

Why are people turning to pyrolysis and gasification for waste treatment?

• Desire to recover valuable product and/or energy from wastes
• Operational difficulties and negative image of incineration
• Perception of new processes as "greener, high technology solutions"
• Constraints on land filling
• Helps meeting recycling targets
• Reduces greenhouse gas production - helps meet Kyoto Protocol targets
• Efforts of end users and suppliers wanting greener carbon content

Environmental Legislation

Klean's end products have important environmental advantages compared to traditional products, giving our fuels a significant edge as governments pass new and more stringent environmental legislation.

In 2006, the U.S. the Environmental Protection Agency (EPA) has reduced the allowable sulfur content of diesel fuel from 500 parts per million (ppm) to 15 ppm. The European Union has imposed new legislation that mandates a limit of 10 ppm. Under the definitions contained in the 1992 Energy Policy Act, these new fuels can be derived from synthetic gas from alternative feed stocks such as municipal solid waste, scrap tires and waste plastics are defined as alternative fuels.

Compliance with this new legislation will add to refining costs, raising diesel fuel prices. In addition, refineries are faced with the challenge that crude oil is generally getting heavier, making it harder and more expensive to raise to the new stringent standards. It is highly unlikely that these improvements in fuel quality can be achieved without using a technique such as blending zero sulfur diesels into the current crude based product mix.