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Title: Exploratory study of some potential environmental impacts of CO2 sequestration in unmineable coal seams

Abstract

An initial investigation into the potential environmental impacts of CO2 sequestration in unmineable coal seams has been conducted, focusing on changes in the produced water during enhanced coalbed methane (ECBM) production, using a CO2 injection process (CO2-ECBM). A high volatile bituminous coal, Pittsburgh No. 8, was reacted with synthetic produced water and gaseous carbon dioxide at 40°C and 50 bar to evaluate the potential for mobilisation of toxic metals during CO2-ECBM/sequestration. Microscopic and X-ray diffraction analysis of the post-reaction coal samples clearly show evidence of chemical reaction and chemical analysis of the synthetic produced water shows substantial changes in composition. These results suggest that changes to the produced water chemistry and the potential for mobilising toxic trace elements from coal beds are important factors to be considered when evaluating deep, unmineable coal seams for CO2 sequestration.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV
Sponsoring Org.:
USDOE - Office of Fossil Energy (FE)
OSTI Identifier:
915620
Report Number(s):
DOE/NETL-IR-2007-177
Journal ID: ISSN 0957-4352 print; 1741-5101 online; TRN: US200816%%94
DOE Contract Number:
None cited
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Environment and Pollution; Journal Volume: 29; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; BITUMINOUS COAL; CARBON DIOXIDE; CHEMICAL ANALYSIS; CHEMICAL REACTIONS; COAL; COAL DEPOSITS; COAL SEAMS; ENVIRONMENTAL IMPACTS; TRACE AMOUNTS; WATER; WATER CHEMISTRY; X-RAY DIFFRACTION; geological sequestration; carbon dioxide; CO2 sequestration; carbon sequestration; coal bed methane; environmental impact; unmineable coal seams; toxic metals; water chemistry; toxic trace elements

Citation Formats

Hedges, S.W., Soong, Y., Jones, R.J., Harrison, D.K., Irdi, G.A., Frommell, E.A., Dilmore, R.M., and White, C.M. Exploratory study of some potential environmental impacts of CO2 sequestration in unmineable coal seams. United States: N. p., 2007. Web. doi:10.1504/IJEP.2007.014232.
Hedges, S.W., Soong, Y., Jones, R.J., Harrison, D.K., Irdi, G.A., Frommell, E.A., Dilmore, R.M., & White, C.M. Exploratory study of some potential environmental impacts of CO2 sequestration in unmineable coal seams. United States. doi:10.1504/IJEP.2007.014232.
Hedges, S.W., Soong, Y., Jones, R.J., Harrison, D.K., Irdi, G.A., Frommell, E.A., Dilmore, R.M., and White, C.M. Mon . "Exploratory study of some potential environmental impacts of CO2 sequestration in unmineable coal seams". United States. doi:10.1504/IJEP.2007.014232.
@article{osti_915620,
title = {Exploratory study of some potential environmental impacts of CO2 sequestration in unmineable coal seams},
author = {Hedges, S.W. and Soong, Y. and Jones, R.J. and Harrison, D.K. and Irdi, G.A. and Frommell, E.A. and Dilmore, R.M. and White, C.M.},
abstractNote = {An initial investigation into the potential environmental impacts of CO2 sequestration in unmineable coal seams has been conducted, focusing on changes in the produced water during enhanced coalbed methane (ECBM) production, using a CO2 injection process (CO2-ECBM). A high volatile bituminous coal, Pittsburgh No. 8, was reacted with synthetic produced water and gaseous carbon dioxide at 40°C and 50 bar to evaluate the potential for mobilisation of toxic metals during CO2-ECBM/sequestration. Microscopic and X-ray diffraction analysis of the post-reaction coal samples clearly show evidence of chemical reaction and chemical analysis of the synthetic produced water shows substantial changes in composition. These results suggest that changes to the produced water chemistry and the potential for mobilising toxic trace elements from coal beds are important factors to be considered when evaluating deep, unmineable coal seams for CO2 sequestration.},
doi = {10.1504/IJEP.2007.014232},
journal = {International Journal of Environment and Pollution},
number = 4,
volume = 29,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • An initial investigation into the potential environmental impacts of CO2 sequestration in unmineable coal seams has been conducted, focusing on changes in the produced water during enhanced coalbed methane (ECBM) production using a CO2 injection process (CO2-ECBM). Two coals have been used in this study, the medium volatile bituminous Upper Freeport coal (APCS 1) of the Argonne Premium Coal Samples series, and an as-mined Pittsburgh #8 coal, which is a high volatile bituminous coal. Coal samples were reacted with either synthetic produced water or field collected produced water and gaseous carbon dioxide at 40 οC and 50 bar to evaluatemore » the potential for mobilizing toxic metals during CO2-ECBM/sequestration. Microscopic and x-ray diffraction analysis of the post-reaction coal samples clearly show evidence of chemical reaction, and chemical analysis of the produced water shows substantial changes in composition. These results suggest that changes to the produced water chemistry and the potential for mobilizing toxic trace elements from coalbeds are important factors to be considered when evaluating deep, unmineable coal seams for CO2 sequestration.« less
  • This is the fourth semi-annual Technical Progress report under the subject agreement. During this report period, progress was made on developing the south well site, reclaiming the north access road, and assessing drilling at the north well site. These aspects of the project, as well as progress on public communications, are discussed in detail in this report.
  • The availability of clean, affordable energy is essential for the prosperity and security of the United States and the world in the 21st century. Carbon dioxide (CO{sub 2}) emissions to the atmosphere are an inherent part of energy-related activities, such as electricity generation, transportation, and building systems. These energy-related activities are responsible for roughly 85% of the U.S. greenhouse gas emissions, and 95% of these emissions are dominated by CO{sub 2}. Over the last few decades, an increased concentration of CO{sub 2} in the earth's atmosphere has been observed. Many scientists believe greenhouse gases, particularly CO{sub 2}, trap heat inmore » the earth's atmosphere. Carbon sequestration technology offers an approach to redirect CO{sub 2} emissions into sinks (e.g., geologic formations, oceans, soils, and vegetation) and potentially stabilize future atmospheric CO{sub 2} levels. Coal seams are attractive CO{sub 2} sequestration sinks, due to their abundance and proximity to electricity-generation facilities. The recovery of marketable coal bed methane (CBM) provides a value-added stream, reducing the cost to sequester CO{sub 2} gas. Much research is needed to evaluate this technology in terms of CO{sub 2} storage capacity, sequestration stability, commercial feasibility and overall economics. CONSOL Energy, with support from the U.S. DOE, is conducting a seven-year program to construct and operate a coal bed sequestration site composed of a series of horizontally drilled wells that originate at the surface and extend through overlying coal seams in the subsurface. Once completed, the wells will be used to initially drain CBM from both the upper (mineable) and lower (unmineable) coal seams. After sufficient depletion of the reservoir, centrally located wells in the lower coal seam will be converted from CBM drainage wells to CO{sub 2} injection ports. CO{sub 2} will be measured and injected into the lower unmineable coal seam while CBM continues to drain from both seams. In addition to metering all injected CO{sub 2} and CBM produced, the program includes a plan to monitor horizontal migration of CO{sub 2} within the lower seam. This is the second Technical Progress report for the project. Progress to date has been focused on pre-construction activities; in particular, attaining site approvals and securing property rights for the project. This report provides a concise overview of project activity this period and plans for future work. This is the second semi-annual Technical Progress report under the subject agreement. During this report period, progress was made in completing the environmental assessment report, securing land and coal rights, and evaluating drilling strategies. These aspects of the project are discussed in detail in this report.« less
  • This is the third semi-annual Technical Progress report under the subject agreement. During this report period, substantial progress was made on finalizing NEPA approval, securing well permits for the project wells, developing the well sites, and drilling at the north well site. These aspects of the project, as well as progress on public communications, are discussed in detail in this report.
  • The availability of clean, affordable energy is essential for the prosperity and security of the United States and the world in the 21st century. Emissions of carbon dioxide (CO{sub 2}) into the atmosphere are an inherent part of electricity generation, transportation, and industrial processes that rely on fossil fuels. These energy-related activities are responsible for more than 80 percent of the U.S. greenhouse gas emissions, and most of these emissions are CO{sub 2}. Over the last few decades, an increased concentration of CO{sub 2} in the earth's atmosphere has been observed. Carbon sequestration technology offers an approach to redirect CO{submore » 2} emissions into sinks (e.g., geologic formations, oceans, soils and vegetation) and potentially stabilize future atmospheric CO{sub 2} levels. Coal seams are attractive CO{sub 2} sequestration sinks, due to their abundance and proximity to electricity-generation facilities. The recovery of marketable coalbed methane (CBM) provides a value-added stream, potentially reducing the cost to sequester CO{sub 2} gas. Much research is needed to evaluate this technology in terms of CO{sub 2} storage capacity, sequestration stability, commercial feasibility and overall economics. CONSOL Energy Inc., Research & Development (CONSOL), with support from the US DOE, has embarked on a seven-year program to construct and operate a coal bed sequestration site composed of a series of horizontally drilled wells that originate at the surface and extend through two overlying coal seams. Once completed, all of the wells will be used initially to drain CBM from both the upper (mineable) and lower (unmineable) coal seams. After sufficient depletion of the reservoir, centrally located wells in the lower coal seam will be converted from CBM drainage wells to CO{sub 2} injection ports. CO{sub 2} will be measured and injected into the lower unmineable coal seam while CBM continues to drain from both seams. In addition to metering all injected CO{sub 2} and recovered CBM, the program includes additional monitoring wells to further examine horizontal and vertical migration of CO{sub 2}. This is the fifth Technical Progress report for the project. Progress this period was focused on reclamation of the north access road and north well site, and development of revised drilling methods. This report provides a concise overview of project activities this period and plans for future work.« less