18. COAL GASIFICATION AND COMBUSTION TECHNOLOGIES   

Coal gasification offers a versatile and clean way to convert the energy content of coal into electricity, hydrogen, other high quality transportation fuels, as well as high-value chemicals to meet specific market needs.  Most importantly, in a time of electricity and fuel price spikes, flexible gasification systems can provide a capability to operate on low-cost, widely-available feedstocks.  Furthermore, gasification may be one of the best ways to produce clean liquid fuels from coal, and clean-burning hydrogen for tomorrow's automobiles and power-generating fuel cells.  Hydrogen and other coal-derived gases also can be used to fuel power-generating turbines or used as chemical "building blocks" for a wide range of commercial products.  The DOE Office of Fossil Energy is working on coal gasifier technology advances that enhance efficiency, environmental performance, and reliability. 

In addition, new materials, ideas, and concepts are required to significantly improve performance and reduce the costs of existing fossil systems or to enable the development of new systems and capabilities.  The Fossil Energy Materials Program conducts research and development on high-performance materials for longer-term fossil energy applications, including gas separations and storage.  The program is concerned with operation in the hostile conditions created when fossil fuels are converted to energy.  These conditions include high temperatures, elevated pressures, and corrosive environments (reducing conditions, gaseous alkali). Grant applications are sought only for the following subtopics:

a. High Temperature Heat Recovery Integrated Gasification Combined Cycle (IGCC)—The National Energy Technology Laboratory’s Clean Coal Technology program includes two IGCC projects, one at the Polk Power Station operated by Tampa Electric Company (TEC) and one at the Wabash River Coal Gasification Repowering Project operated by Wabash River Energy Ltd.  Both facilities experienced similar operational problems associated with their high-temperature heat recovery units (HTHRU).  Both IGCC facilities experienced significant down time as a result of erosion, corrosion, fouling and pluggage of the HTHRU.

At the Wabash IGCC facility, hot syngas from the gasifier flows to the HTHRU to produce high-pressure steam.  The HTHRU is a vertical firetube steam generator that is used as a syngas cooler.  It has hot syngas on the tube side.  The syngas is cooled from 1,900°F to about 700°F in the HTHRU generating 1,600 psia steam.  Steam from the HTHRU is superheated by the gas turbine heat recovery system for power generation.  Major components of the Wabash syngas cooling/steam generation system are the firetube heat recovery boiler and the high-pressure steam drum.  Ash deposits have occurred in the HTHRU and have created operational difficulties and caused high system pressure drops.  Removal of ash deposits required significant down time.  The situation was further exacerbated by material spalling from the ash deposits and then lodging in the boiler tubes, plugging them and further increasing downtime due to time required to remove the plugs.  The rate and extent of ash deposition in the syngas cooler is a function of operational conditions, and is “proportional to the number of thermal cycles (full or partial load trips) experienced in the system”.   As the operators gained experience with the gasifier, improved reliability occurred, thereby decreasing the number of thermal cycles and decreasing the rate of ash deposition.

At the Polk Power Station hot syngas leaves the gasifier and passes through a radiant syngas cooler (RSC).  The RSC had a design exit temperature of about 1350°F, but due to the fact that it was oversized, the actual exit temperature is around 1050°F.  The syngas then enters the convective syngas cooler (CSC) flowing at high velocity to increase the heat transfer coefficient.  Boiler feed water circulates through the CSC on the shell side by natural convection generating 1650 psia steam.  The CSC system consists of 6 heat exchangers with associated interconnecting piping.  Each one is a fire-tube shell and tube heat exchanger.  Syngas leaves between 700 and 750°F.  The CSC has been the source of a variety of operational problems at Polk, caused by ash deposits that form in the CSC.  In addition to plugging problems, these deposits can cause leaks to occur by deflecting the particulate loaded syngas flow, resulting in tube metal loss via erosion.  The CSC was identified as a major problem resulting in 478 unplanned outage hours, more than any other equipment at the station.  Heat exchanger fouling and subsequent plugging and/or erosion are major contributors to lowering IGCC availability.

Grant applications are sought for:  novel ideas and approaches that can significantly reduce or even eliminate these problems without adversely affecting the thermal performance of the system.

Questions – contact Ronald Breault (ronald.breault@netl.doe.gov)

b. Novel Concepts in Industrial Gasification—Natural gas is used as a feedstock in many industries in addition to the power production industry.  However, the increasing cost of natural gas, along with the likelihood that the cost will continue to increase, is driving the development of new technologies to improve the economic return for coal gasification processes outside that of power production.  Therefore, grant applications are sought to develop novel technologies to make gasification, from a feedstock of at least 75% coal, more attractive for industrial use, including the production of synthesis gas, hydrogen or substitute natural gas (SNG).  New or revisited gasification concepts, e.g., hydro-, or catalytic gasification are encouraged. Target industries include small utility, metals, chemicals, pulp and paper, and glass.  Proposed approaches should demonstrate a significant impact on the chosen industry or industries – the larger the niche for the gasification process, the better.  The proposed novel technology and overall process may be for either near term or long term deployment into industry.  DOE envisions that the industrial applications scale would be in the 25 to 100 MWe equivalent range. 

Grant applications are sought to:  address optimizing the gasifier operating conditions for a specific industrial application.  For example, for hydrogen/SNG production, the operating conditions and design characteristics that might reasonably be expected to influence the methane and/or hydrogen content include:  pressure; temperature; feed media and system (dry vs. wet slurry with water); residence time and internal or external recirculation/recycle rates; sizing of reaction chamber; feed rates of oxidant or steam; particle sizing; feed injector mixing patterns; number and design of gasification stages; internal/external shift reaction catalysts; and internal separation mechanisms, such as sorbents and/or membranes.  Process operating conditions that can offer potential advantages in efficiency and cost are preferred, and an assessment of these factors should be included as part of the data evaluation component of the research project. Limited modeling to support experimental work is acceptable, but grant applications that involve extended, idealistic modeling of gasification systems, without supporting experimental data, are not of interest.

Grant applications must also:  (1) define the products of the gasification process and show whether they will be exported, used within the plant, or a combination of each – it is not necessary for power to be one of the products, although it may be; and (2) include in Phase I an analysis of plant thermal efficiency and economics, in comparison to competing technologies.  

Questions – contact Elaine Everitt (Elaine.everitt@netl.doe.gov)

c. Novel Concepts In Hydrogen Production And Process Intensification—The DOE’s FutureGen project, now in its early planning stage, aims to demonstrate the technical/economical feasibility of a coal gasification plant to produce power, with near-zero emissions including the emission of carbon dioxide.  The strategy is to convert coal to hydrogen that would be used as fuel for fuel cells and/or gas turbines, with the concurrent sequestering of the concentrated carbon dioxide from the processing and power blocks.  Under this scheme, coal first would be gasified to produce synthesis gas (mainly hydrogen and carbon monoxide).  This would be followed by processes for removing impurities and producing additional hydrogen through the water-gas-shift reaction.  Finally, the hydrogen would be separated from other compounds.

Hydrogen has the potential to be used in a number of end-use applications each having its own purity standards.  New materials and processes are necessary to remove trace quantities of impurities such as CO, N2, S, metals, and other impurities to manufacture high purity hydrogen for a variety of applications.  Therefore, grant applications are sought to develop advanced processes, materials and devices for producing ultra-pure hydrogen from coal-derived synthesis gas.  While, the primary interest is processes that remove all impurities,

Grant applications should demonstrate:  familiarity with end-use purity specifications and ensure that the level of hydrogen purity provided by the proposed concept matches the appropriate end-use (i.e., hydrogen turbines, fuel cell, modified internal combustion engines).

Process Intensification through the development of advanced technologies that offer the potential to consolidate two or more unit processes/unit operations in one module could provide higher efficiencies, lower capital costs and a smaller overall footprint for the coal-to-hydrogen plant.  One such example is the combination of water-gas-shift and hydrogen separation into a single step, carried out at temperatures compatible with the synthesis gas that exits from the cleanup step.  (Current development work shows that clean syngas can be produced in the 350oC to 400oC range.) 

Grant applications are sought to:  develop novel processes that may be located inside the gasifier as well as those located outside the gasifier to produce a syngas with high hydrogen content (>70% by vol.).  Proposed approaches should provide robust performance; high hydrogen throughput, selectivity, and recovery; long system life; and low operating cost.  These new technologies should be able to operate at pressures compatible with gasifier pressures up to 1000 psig.  In addition, they should have high tolerance for the low levels of sulfur and the other impurities that are present in feed gas.  Grant applications should demonstrate familiarity with current commercial technologies to produce hydrogen from coal, as well as with the ongoing R&D supported by DOE in the coal-to-hydrogen program. 

Questions - contact Patricia Rawls (patricia.rawls@netl.doe.gov)

d. Hydrogen and Syngas, Novel Concepts in Liquid Fuels Production and Process Intensification with Carbon Management—The United States’ economy is inextricably linked to liquid fuels to sustain its large transportation sector.  These liquid fuels are largely derived from crude oil, but world crude oil prices have skyrocketed from around $10 per barrel to over $60 per barrel within the past seven years.  Consequently, an immediate and viable alternative to crude oil is needed to moderate the effect of price hikes and provide an interim bridge until some other fuel source can commercially supplant petroleum-based fuels.  The few candidate resources to produce liquid fuels include biomass, oil sands, oil shale, and coal, but coal is the most promising resource with over 250 billion tons of known reserves.   

Coal-derived liquid fuels produced via Fischer-Tropsch (FT) processes are fungible with the existing petroleum distribution, storage, and end-use infrastructure.  Furthermore, these fuels are zero-sulfur paraffinic hydrocarbons that are similar to diesel with a high cetane number (~75) compared to petroleum diesel (~45).  This provides for efficient operation in high-pressure compression-ignition engines and reduced particulate emissions.  Coal-derived liquid fuels can also be used as hydrogen carriers, which when reformed can produce hydrogen for transportation, fuel cells, and other forms of distributed hydrogen generation.

Although the FT process is commercial in South Africa and Malaysia, several challenges face the production of liquid fuels from coal.  The coal-derived synthesis gas contains trace contaminants that poison the catalysts used in the synthesis of liquid fuels.  Some catalysts are sensitive to even ppb levels of these contaminants.  In addition, the ratio of hydrogen-to-carbon monoxide in the feed may need to be adjusted prior to liquid fuels synthesis.  Catalyst separation from the waxes that result from FT synthesis also presents a challenge.

Other challenges facing the conversion of coal to liquid fuels are efficiency, footprint, and lower capital costs.  These challenges may be overcome through process intensification, consolidating two or more unit operations into a single integrated module that in some cases produces a synergy between certain unit operations that increase efficiency and lowers capital costs. 

Furthermore, in today’s environment, a third technology is needed in the production of liquid fuels from coal, namely carbon dioxide capture.  Large quantities of carbon dioxide are released when coal is converted to another energy form.  Carbon dioxide emissions prompt concerns over global climate change; therefore it is imperative that any new process should be able to operate on a carbon dioxide constrained environment.

Grant applications must:  describe a novel, highly selective process for producing liquid fuels from coal.  Concepts which utilize biomass or any feedstock other than coal or petroleum coke/resid are not sought.  For processes based on the gasification of coal and the subsequent conversion of synthesis gas to liquid fuels, research work on the coal gasification system is not desired, however, the commercial gasifier, gas cleanup, and other components necessary to provide the required synthesis gas for conversion to liquid fuel must be identified.  Grant applications should demonstrate familiarity with current commercial technologies for producing liquid fuels from coal as well as with ongoing R&D in this area.

Grant applications should:  include a concept providing for the integration of two or more unit operations to demonstrate process intensification.  The objective of process intensification is to achieve higher efficiencies, lower capital costs, and a smaller overall footprint over what can be achieved by utilizing separate components for each required unit operation.  This may include novel processes that may be located inside the gasifier as well as those located outside the gasifier.  In addition, grant applications should also provide for a sequestration-ready carbon dioxide stream.

It is expected that experimental work will be conducted at laboratory and/or bench-scale to demonstrate the technical feasibility of the novel concepts proposed.  In support of the experimental work proposed, a preliminary analysis (with a block flow diagram and energy and mass balances) should be provided to aid in assessing the commercial potential of the concept.  All emissions and environmental concerns, including the capture of any carbon dioxide must be addressed.  The analysis must also address a conceptual strategy for achieving liquid fuel purity sufficient for existing transport applications with minimal refining.  Any byproduct species must be identified, including estimated amounts and mode of disposition.

Questions- contact Robert Kornosky (robert.kornosky@netl.doe.gov)

References:

Subtopic a:  High Temperature Heat Recovery Integrated Gasification Combined Cycle (IGCC)

1.      Wabash River Coal Gasification Repowering Project,” Final Technical Report, August 2000.  (Full report available at:  http://www.fischer-tropsch.org/DOE/DOE_reports/Wabash%20River%20Repowering/29310/29310-31/29310-31_toc.htm)

2.      Wabash River Coal Gasification Repowering Project:  A DOE Assessment,” January, 2002.  (Full text available at:  http://www.fischer-tropsch.org/DOE/DOE_reports/Wabash%20River%20Repowering/2002/2002-1164/2002-1164%20-%20DOE%20ASSMNT.pdf)

3.      McDaniel, J. E. and Hornick, M., “Polk Power Station IGCC:  6th Year of Commercial Operation,” presented at the 2002 Gasification Technologies Conference, San Francisco, October 2002.  (Full text available at http://www.gasification.org/Docs/2002_Papers/GTC02011.pdf)

4.      eia:  Energy Information Administration U.S. DOE Website.  (URL: http://tonto.eia.doe.gov/dnav/pet/hist/wtotworldw.htm )

Subtopic b:  Novel Concepts in Industrial Gasification

5.      “Gasification – Advanced Gas Separation:  O2 Separation,” U.S. DOE National Energy Technology Laboratory Website.  (URL:  http://www.netl.doe.gov/technologies/coalpower/gasification/gas-sep/o2-sep.html)

6.      Air Products, “ITM Oxygen:  The New Oxygen Supply for the New IGCC Market,” 2005 Gasification Technology Council presentation.  (URL:  http://www.gasification.org/Docs/2005_Papers/43ARMS.pdf)

Subtopic c:  Novel Concepts In Hydrogen Production And Process Intensification

7.      Lin, Y. S., “Microporous and Dense Inorganic Membranes:  Current Status and Prospective,” Separation and Purification Technology, 25:39–55, 2001.  (Abstract and ordering information available at:  http://www.sciencedirect.com/.  On menu at left, Browse by [journal] title for volume and page number.)

8.      FutureGen – Tomorrow’s Pollution-Free Power Plant,” U.S. DOE Office of Fossil Energy Website. (URL:  http://www.fossil.energy.gov/programs/powersystems/futuregen/index.html)   

9.      “Hydrogen and Clean Fuels Research,” U.S.DOE Office of Fossil Energy Website.  (URL:  http://www.fe.doe.gov/programs/fuels/index.html)

10.  Tong, J., et al., “Thin Defect-Free Pd Membrane Deposited on Asymmetric Porous Stainless Steel Substrates,” Industrial & Engineering Chemistry Research, 44(21): 8025 -8032, October 2005.  (ISSN: 08885885) (Abstract and ordering information available at: http://sciserver.lanl.gov/cgi-bin/sciserv.pl?collection=journals&journal=08885885&issue=v44i0021.  Scroll down to title and click on “Abstract”.  To purchase, click on link in upper right corner.)

11.  Kamakoti, P., et al., “Prediction of H2 Flux thru Sulfur-Tolerant Dense Binary Alloy Membranes,” Science Magazine, Vol. 307, January 28, 2005 .  (Abstract and ordering information available at: http://www.sciencemag.org/cgi/search?src=hw&site_area=sci&fulltext=Prediction+of+H2+Flux+thru+Sulfur-Tolerant+Dense+Binary+Alloy+Membranes+Volume+307&search_submit.x=9&search_submit.y=5)

12.  Balachandran, U., “Hydrogen Permeation and Chemical Stability of Cermet Membranes,Electrochemical and Solid State Letters, 8(12), J35-J37, 2005. (ISSN:  1099-0062) (Abstract at:  http://ecsdl.org/.  Click on journal title and browse for volume and issue.)

13.  Roark, S. E., et al., “Dense Layered Membranes for Hydrogen Separation,” U.S. Patent No. 7,001,446 B2, February 21, 2006. (Full text available at: http://www.freepatentsonline.com/7001446.html )

14.  Doong, S., et al., “A Novel Membrane Reactor for Direct Hydrogen Production from Coal,” DOE Technical Report, January 2006.  (OSTI ID:  876470) (Full text available at: (http://www.osti.gov/bridge/product.biblio.jsp?query_id=0&page=0&osti_id=876470)

Subtopic d:  Hydrogen and Syngas, Novel Concepts in Liquid Fuels Production and Process Intensification with Carbon Management

15.  “Gasification: Advanced Gasification,” U.S. DOE National Energy Technology Laboratory Website.  (URL:   http://www.netl.doe.gov/technologies/coalpower/gasification/adv-gas/index.html)  

16.  “Hydrogen and Other Clean Fuels,” U.S. Department of Energy Office of Fossil Energy Website.  (URL:  http://fossil.energy.gov/programs/fuels/)  

17.  Breckenridge, W., et al., “Use of SELEXOL Process in Coke Gasification to Ammonia Project,” paper presented at the Laurance Reid Gas Conditioning Conference, Norman, OK, Feb. 27 – Mar. 1, 2000.  (http://www.uop.com/objects/92SelexCokeGasifAmm.pdf)

18.  Hydrogen-from-Coal Program:  Research, Development, and Demonstration Plan (for the period 2004 through 2015), June 10, 2004 .  (Available at:  http://www.fe.doe.gov/programs/fuels/index.html. Scroll down to “Hydrogen from Coal—Future Technologies”, and select “Hydrogen from Coal R&D”.)

 

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