Gasification

First we need to explain gasification. Gasification is a very old industrial practice that has been with us throughout the industrial revolution and used continuously in various forms. Gasification is a thermal process where heat (and sometimes pressure) is applied to carbon based materials, usually coal or biomass, in an air reduced container. The materials are not allowed to burn but instead are broken down into tars, char, and gas. Gasification is closely related to combustion but distinctly different. Low temperature or poorly engineered gasification will produce lots of tar which is bad for our purposes, the goal of high temperature gasification is to achieve a complete breakdown of the tars into gases.

The output gas is called Syngas, which is short for synthesis gas, and it is primarily a blend of carbon monoxide and hydrogen. The higher the ratio of hydrogen, the more potent the fuel. Pure syngas is a green fuel with a very clean combustion profile. It is about as clean a fuel that exists for burning, and can be used in steam boilers or electrical turbines, but syngas can be used for far more than simply burning. Syngas is an excellent feedstock for a variety of purposes, it can be made into liquid fuels such as ethanol, methanol, diesel, or jet fuel (kerosene). Syngas can be used to make chemicals and plastics, including biodegradable plastics. Adding methane to syngas produces Synthetic Natural Gas. Syngas can also be broken apart to separate the H2 from CO, and can be a major source of hydrogen for a potential hydrogen economy as well enabling carbon sequestering. All of these outputs are worthy of a discussion of their own and my goal will be to get to each one in turn and present the business perspective on them.

Gasification, primarily of coal, has been used for a very long time. Here in the US the first municipal power systems utilized "town gas" from coal gasification to light street lamps in the late 1800's. Chemical industries have utilized coal gasification to produce chemicals since the 1950s. Overseas countries under embargo have utilized coal gasification to produce liquid fuels for decades. The Germans used coal to liquids in WWII and in South Africa the energy firm Sasol has done coal to liquids for decades and continues to be a world leader in the technology. After WWII woodgas powered automobiles were popular in Europe when gasoline was in short supply and home-built wood gasifiers allowed people to go 1 mile per pound of wood. There is some real fascinating history to gasification and hopefully I will can get permission to post some of the materials I have collected that go into detail.

The fundamental premise and promise of gasification, is the ability to take a wide variety of raw materials, many of which are considered waste, and reduce them to a common gas. The gas in turn can be used for a variety of outputs, and do so in a manner that is green.

Raw materials can include unconventional fossil fuels such as high sulphur coal, oil shale, tar sands, pet coke, or municipal waste, plastics, chemicals, agricultural waste whether plant matter or manure, and also sewage sludge.

The ultra high temperature processes, above 1200 F will melt metals and glass in the feedstock and will destroy organic hazards such as poisons and infectious matter. At high temperatures a process called "molecular disassociation" occurs where materials are disintegrated and torn apart at a molecular level destroying their toxic nature. So these gasifiers can serve as hazardous waste disposal sites as well, but more about that later.

Enough for now, as you can probably see there is enough to talk about here to fill a bunch of books, my challenge is to maintain a coherent thread.