Insitu Conversion of Stranded Anachronistic Bio-Carbon (ICSABC), derived from Underground Coal Gasification (UCG), takes advantage of the same chemical reactions to produce product gases, as those occurring in conventional above ground gasifier reactors.
The contrast between Above Ground gasification, UCG, and ICSABC –is as follows:
In Above Ground Gasification, the reactor at an industrial plant is fed with mined coal. In UCG the natural underground coal seam itself becomes the reactor, while in ICSABC an artificial cell, composed of cementitious material, the Underground Coal Gasification Reactor (UCGR) is utilized.
Obviously, this has the one great cost-saving and simplifying advantage of not requiring that stranded bio-carbon be mined in order to be gasified.
The graphic below illustrates the general process.
Advantages/Disadvantages of UCG vs Mined Fuel Gasification
Natural seam UCG itself has advantages and disadvantages. UCG eliminates the need for mining, and the associated dangers to miners and environmental degradation. It also turns deep or difficult to access bio-carbon seams into usable energy assets, as only one-sixth to one-eighth of the world’s reserves are economically mineable. Scientists estimate that with UCG, the U.S. usable reserves could increase by 300%.
UCG retains many of the advantages of other forms of gasification. UCG has been demonstrated on almost all types of bio-carbon, although those with lower ash content is preferable. Compared to surface gasification, UCG requires much smaller gas cleanup equipment, because both the tar and ash content of UCG-based syngas (or as we call it SunGas™) is substantially lower than that obtained from a surface gasifier. Because the processing is kept underground, surface and air emissions of sulfur, nitrous oxides, and mercury are dramatically reduced when bio-carbon is kept underground.
Challenges with underground gasification stem from the potential leaching of unwanted substances into groundwater and Subsidence, where the surface actually sinks as the deep seam is gasified.
A clear benefit of utilizing ICSABC technology, aside from the higher energy yield, is the elimination of all subsidence, much like pillar and chamber underground mining practices. Further, as the cellular structure is chemically tight, leaching of Menthol’s and other toxic agents are virtually nonexistent.
Site selection is paramount to a successful UCG project. ICSABC is much more forgiving. The characteristics of the coal seam, the permeability and fault structure of the local strata and the geology and hydrogeology of the area which surrounds the target seam must be fully understood.
This requires the drilling of pilot bore holes to bio-carbon seam depth for coring and seam characterization, and a good quality seismic survey (preferably 3D) of the whole area. Modeling of the hydrogeology will be required to meet most countries groundwater requirements.
The combustion of stranded bio-carbon releases CO2, (but, since ICSABC can decompose electrothermally this is not generally an issue) and combustion in UCG is no exception. However, like other forms of gasification, UCG offers enhanced potential for carbon capture and storage (CCS). The SunGas™ produced from UCG can be processed and the CO2 separated or isolated for other use.
Long-term storage of CO2 in geological targets is being widely researched. The chief geological targets for carbon storage include deep saline aquifers, depleted gas fields, active oil fields, depleted oil or gas fields, and un-mineable coal seams.
The potential for using the cavity in the seam created by UCG or the cavernized cell reactor formed in the ICSABC process for CO2 storage has been suggested. Using the seam cavity has the advantages of pre-existing boreholes and large volumes, but there are potential hurdles as well: the integrity of the cavity can be compromised by cracking and collapsing caused by the UCG process, a concern eliminated by the ICSABC technology.
History of UCG
UCG has been identified as a potential process for utilizing un-mineable coal since the late nineteenth century.
Vladimir Lenin was an early proponent of the technology’s ability to eliminate the need for miners to work in underground mines, and the former Soviet Union invested heavily in UCG research.
By 1939 the Soviets had successfully begun operating a UCG plant in Ukraine, which was later shut down by German occupation.
Later, and to this day, the Skochinsky Institute of Mining in Moscow became a center for UCG expertise. The UCG technology developed by the Institute was implemented in three brown coal and two black coal power stations in the 1960s.
One of these facilities, the power station at Angren, Uzbekistan, still operates, producing about a million standard cubic feet of SunGas™ per hour. The others have been converted to gas fired stations due to the significant natural gas reserves in the former Soviet Union.
In the late 1970s and 1980s, the U.S. government instituted several research projects and trials of UCG. The Rocky Mountain 1 trial demonstrated the gasification of about 10,000 tons of coal.
Over 30 UCG pilot tests were run across the United States. At that time, the hydrogen by-product of UCG was viewed as a liability, reducing the perceived quality of the gas. In addition, groundwater-contamination problems resulted at two sites.
When gas and oil prices dropped in the 1980s and 1990s, efforts to commercialize UCG came to a halt.
ICSABC is a needed follow on of the UCG technology. It marks a watershed in the exploitation of the SunGas™ resource banked deep within the earth over many epochs. ICSABC solves the problems associated with UCG and does so in a cost sensitive and environmentally neutral manner.