Enhanced coal bed methane recovery

Last updated

Enhanced coal bed methane recovery is a method of producing additional coalbed methane from a source rock, similar to enhanced oil recovery applied to oil fields. Carbon dioxide (CO2) injected into a bituminous coal bed would occupy pore space and also adsorb onto the carbon in the coal at approximately twice the rate of methane (CH4), allowing for potential enhanced gas recovery. [1] This technique may be used in conjunction with carbon capture and storage in mitigation of global warming where the carbon dioxide that is sequestered is captured from the output of fossil fuel power plants.

Coalbed methane, coalbed gas, coal seam gas (CSG), or coal-mine methane (CMM) is a form of natural gas extracted from coal beds. In recent decades it has become an important source of energy in United States, Canada, Australia, and other countries.

In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including deep water marine, lacustrine and deltaic. Oil shale can be regarded as an organic-rich but immature source rock from which little or no oil has been generated and expelled. Subsurface source rock mapping methodologies make it possible to identify likely zones of petroleum occurrence in sedimentary basins as well as shale gas plays.

Enhanced oil recovery, also called tertiary recovery, is the extraction of crude oil from an oil field that cannot be extracted otherwise. EOR can extract 30% to 60% or more of a reservoir's oil, compared to 20% to 40% using primary and secondary recovery. According to the US Department of Energy, there are three primary techniques for EOR: thermal, gas injection, and chemical injection. More advanced, speculative EOR techniques are sometimes called quaternary recovery.

Contents

A research project at ETH Zurich is studying the process of pumping carbon dioxide into unminable coal seams and recovering the methane that is subsequently displaced.

ETH Zurich Swiss Federal Institute of Technology in Zurich

ETH Zurich is a science, technology, engineering and mathematics university in the city of Zürich, Switzerland. Like its sister institution EPFL, it is an integral part of the Swiss Federal Institutes of Technology Domain that is directly subordinate to Switzerland's Federal Department of Economic Affairs, Education and Research. The school was founded by the Swiss Federal Government in 1854 with the stated mission to educate engineers and scientists, serve as a national center of excellence in science and technology and provide a hub for interaction between the scientific community and industry.

An extensive experimental investigation about the process of desorbing methane by adsorbing carbon dioxide in real coal samples was performed. The proof of principle and the technical feasibility of the method could be verified with these measurements. These research results indicate that CBM can become an alternative to conventional natural gas. ECBM provides additional to CBM the advantage of long-term CO2 storage in the underground coal seams. [2]

However, without other incentives, enhanced coal bed methane recovery is not economical as the commercial value of the released methane does not completely offset the cost of pumping. [3]

Penetration of CO2 into coal is simulated using a stress-enhanced diffusion model. [4] [5]

See also

Global Methane Initiative

The Global Methane Initiative (GMI) is a voluntary, international partnership that brings together national governments, private sector entities, development banks, NGOs and other interested stakeholders in a collaborative effort to reduce methane gas emissions and advance methane recovery and use as a clean energy source. National governments are encouraged to join GMI as Partner Countries, while other non-State organizations may join GMI's extensive Project Network. As a public-private initiative, GMI creates an international platform to build capacity, development methane abatement strategies, engage in technology transfer, and remove political and economic barriers to project development for emissions reduction.

Further reading

Related Research Articles

Carbon sink

A carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. The process by which carbon sinks remove carbon dioxide (CO
2
) from the atmosphere is known as carbon sequestration. Public awareness of the significance of CO2 sinks has grown since passage of the Kyoto Protocol, which promotes their use as a form of carbon offset. There are also different strategies used to enhance this process.

Coalbed methane extraction is a method for extracting methane from a coal deposit.

National Energy Technology Laboratory

The National Energy Technology Laboratory (NETL) is a U.S. national laboratory under the Department of Energy Office of Fossil Energy. NETL focuses on applied research for the clean production and use of domestic energy resources. NETL performs research and development on the supply, efficiency, and environmental constraints of producing and using fossil energy resources, while maintaining their affordability.

Coal pollution mitigation

Coal pollution mitigation, often (incorrectly) called clean coal, is a series of systems and technologies that seek to mitigate the pollution and other environmental effects normally associated with the burning of coal, which is widely regarded as the dirtiest of the common fuels for industrial processes and power generation.

Supercritical carbon dioxide

Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.

Carbon capture and storage the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere

Carbon capture and storage (CCS) is the process of capturing waste carbon dioxide from large point sources, such as biomass or fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation. The aim is to prevent the release of large quantities of CO
2
into the atmosphere. It is a potential means of mitigating the contribution of fossil fuel emissions to global warming and ocean acidification. Although CO
2
has been injected into geological formations for several decades for various purposes, including enhanced oil recovery, the long term storage of CO
2
is a relatively new concept. The first commercial example was the Weyburn-Midale Carbon Dioxide Project in 2000. Another example is SaskPower's Boundary Dam. 'CCS' can also be used to describe the scrubbing of CO
2
from ambient air as a climate engineering technique.

Carbon sequestration

Carbon sequestration is the process involved in carbon capture and the long-term storage of atmospheric carbon dioxide or other forms of carbon to mitigate or defer global warming. It has been proposed as a way to slow the atmospheric and marine accumulation of greenhouse gases, which are released by burning fossil fuels.

Clean coal technology is a collection of technologies being developed in attempts to lessen the negative environmental impact of coal energy generation and to mitigate worldwide climate change. When coal is used as a fuel source, the gaseous emissions generated by the thermal decomposition of the coal include sulfur dioxide (SO2), nitrogen oxides (NOx), mercury, and other chemical byproducts that vary depending on the type of the coal being used. These emissions have been established to have a negative impact on the environment and human health, contributing to acid rain, lung cancer and cardiovascular disease. As a result, clean coal technologies are being developed to remove or reduce pollutant emissions to the atmosphere. Some of the techniques that would be used to accomplish this include chemically washing minerals and impurities from the coal, gasification (see also IGCC), improved technology for treating flue gases to remove pollutants to increasingly stringent levels and at higher efficiency, carbon capture and storage technologies to capture the carbon dioxide from the flue gas and dewatering lower rank coals (brown coals) to improve the calorific value, and thus the efficiency of the conversion into electricity. Concerns exist regarding the economic viability of these technologies and the timeframe of delivery, potentially high hidden economic costs in terms of social and environmental damage, and the costs and viability of disposing of removed carbon and other toxic matter.

Western Canadian Sedimentary Basin

The Western Canadian Sedimentary Basin (WCSB) is a vast sedimentary basin underlying 1,400,000 square kilometres (540,000 sq mi) of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. It consists of a massive wedge of sedimentary rock extending from the Rocky Mountains in the west to the Canadian Shield in the east. This wedge is about 6 kilometres (3.7 mi) thick under the Rocky Mountains, but thins to zero at its eastern margins. The WCSB contains one of the world's largest reserves of petroleum and natural gas and supplies much of the North American market, producing more than 16,000,000,000 cubic feet (450,000,000 m3) per day of gas in 2000. It also has huge reserves of coal. Of the provinces and territories within the WCSB, Alberta has most of the oil and gas reserves and almost all of the oil sands.

A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers. Carbon dioxide scrubbers are also used in controlled atmosphere (CA) storage. They have also been researched for carbon capture as a means of combating global warming.

Methanation is the conversion of COx to methane CH4 through hydrogenation. The methanation reactions of COx were first discovered by Sabatier and Senderens in 1902.

Greenhouse gas removal projects are a type of climate engineering that seek to remove greenhouse gases from the atmosphere, and thus they tackle the root cause of global warming. These techniques either directly remove greenhouse gases, or alternatively seek to influence natural processes to remove greenhouse gases indirectly. The discipline overlaps with carbon capture and storage and carbon sequestration, and some projects listed may not be considered to be climate engineering by all commentators, instead being described as mitigation.

The milestones for carbon capture and storage show the lack of commercial scale development and implementation of CCS over the years since the first carbon tax was imposed.

Hydromethanation, [hahy-droh- meth-uh-ney-shuhn] is the process by which methane is produced through the combination of steam, carbonaceous solids and a catalyst in a fluidized bed reactor. The process, developed over the past 60 years by multiple research groups, enables the highly efficient conversion of coal, petroleum coke and biomass into clean, pipeline quality methane.

The Centre for Research into Earth Energy Systems is a Geo-Energy research centre at Durham University. The centre was formed in January 2006, and since then has won a research income of £1.3M per annum. The current Director of CeREES is Professor Jon Gluyas, co-author of textbook Petroleum Geoscience. The Centre is part of the multidisciplinary Durham Energy Institute. CeREES is one of only three academic members of the Carbon Capture and Storage Association and is also a member of the Underground Coal Gasification Association.

The Zonguldak basin of North Western Turkey has been mined for coal since the late 1800s. The basin takes its name after Zonguldak, Turkey, and is approximately 41° N. The Zonguldak basin is the only basin in Turkey with minable coal deposits. Geographically, the Zonguldak is roughly elliptical in shape with its long axis oriented roughly SW – NE, and is adjacent to the Black Sea. Three main regions have been recognized in the Zonguldak basin. These are the Armutcuk, the Zonguldak, and the Amasra from west to east respectively.

Lower-temperature fuel cell types such as the proton exchange membrane fuel cell, phosphoric acid fuel cell, and alkaline fuel cell require pure hydrogen as fuel, typically produced from external reforming of natural gas. However, fuels cells operating at high temperature such as the solid oxide fuel cell (SOFC) are not poisoned by carbon monoxide and carbon dioxide, and in fact can accept hydrogen, carbon monoxide, carbon dioxide, steam, and methane mixtures as fuel directly, because of their internal shift and reforming capabilities. This opens up the possibility of efficient fuel cell-based power cycles consuming solid fuels such as coal and biomass, the gasification of which results in syngas containing mostly hydrogen, carbon monoxide and methane which can be cleaned and fed directly to the SOFCs without the added cost and complexity of methane reforming, water gas shifting and hydrogen separation operations which would otherwise be needed to isolate pure hydrogen as fuel. A power cycle based on gasification of solid fuel and SOFCs is called an Integrated Gasification Fuel Cell (IGFC) cycle; the IGFC power plant is analogous to an integrated gasification combined cycle power plant, but with the gas turbine power generation unit replaced with a fuel cell power generation unit. By taking advantage of intrinsically high energy efficiency of SOFCs and process integration, exceptionally high power plant efficiencies are possible. Furthermore, SOFCs in the IGFC cycle can be operated so as to isolate a carbon dioxide-rich anodic exhaust stream, allowing efficient carbon capture to address greenhouse gas emissions concerns of coal-based power generation.

The Petra Nova project is a coal-energy-sector/ clean-energy project designed to reduce carbon emissions from one of the boilers of a coal burning power plant in Thompsons, Texas. It is a multi-million dollar project taken up by NRG Energy and JX Nippon Oil to retrofit one of the boilers at their WA Parish Generating Station with a post-combustion carbon capture treatment system to treat a portion of the atmospheric exhaust emissions from the retrofitted boiler. The plant entered commercial service in 1977, and the new carbon emissions reduction system was first put into operation on January 10, 2017. The project is designed to annually capture approximately 33% of the carbon dioxide emissions from the plant's boiler #8.

References

  1. Wickstrom, Lawrence H.; Ernie R. Slucher; Mark T. Baranoski; Douglas J. Mullett (2008). "Geologic Assessment of the Burger Power Plant and Surrounding Vicinity for Potential Injection of Carbon Dioxide" (PDF). Columbus, Ohio: Ohio Geological Survey. Open-File Report 2008-1. Archived from the original (PDF) on 2008-12-31. Retrieved 2008-06-21.
  2. Investigation of Enhanced Coal Bed Methane (ECBM) Processes - Gravimetric Adsorption Measurements under Realistic Conditions
  3. "ETH - SPL - Enhanced coal bed methane recovery". ETH Zurich. 2006-08-31. Archived from the original on 2011-07-06.
  4. F. J. Vermolen, M.G. Gharasoo, P. L. J. Zitha, J. Bruining. (2009). Numerical Solutions of Some Diffuse Interface Problems: The Cahn-Hilliard Equation and the Model of Thomas and Windle. IntJMultCompEng,7(6):523543.
  5. A. Mikelić and J. Bruining. (2008). Analysis of Model Equations for Stress-Enhanced Diffusion in Coal Layers. Part I: Existence of a Weak solution. SIAM J. Math. Anal.,40:1671-1691