A wide range of research, development, and demonstration (RD&D) activities are being conducted to improve the fuel and product versatility, efficiency, and economics of gasification processes. Most of the research being done today focuses on coal gasification; however, the potential for the gasification industry is much broader and so is the potential for gasification research.
Challenges
For gasification to achieve widespread market penetration in the most significant markets – power generation, chemical processing, and gas and liquid fuel synthesis – technology improvements are required to reduce capital and operating costs relative to competing technologies. Global gasification RD&D seeks to reduce costs through several general objectives, including:
- Improving gasifier efficiency and process control;
- Improving process train reliability, reducing downtime and expenses from redundant process components;
- Improving the flexibility of gasification processes to handle a wider variety of grades and types of feedstocks, including low rank coal.
Research leading to technological developments in the capture and storage of carbon dioxide (CO2), along with increasing regulatory limits on the release of CO2 could give gasification a competitive advantage in future markets. Gasification has a distinct economic advantage over competing technologies in capturing and storing CO2 from process streams.
The following pages highlight the major gasification RD&D programs taking place in the United States and around the world.
United States
The DOE's Office of Fossil Energy, as part of their Advanced Energy Systems Program, runs the Gasification Systems Research and Development (R&D) Program. The strategic objective of the Advanced Energy Systems Program is to create public-private partnerships to provide technology to ensure continued electricity production from the extensive U.S. fossil fuel resource, including control technologies to permit reasonable-cost compliance with emerging regulations.
Having collaborated with industry to bring coal gasification to commercial-scale applications, the Gasification Systems Program is now shifting its focus to refining and expanding upon the gasification processes already developed to bring the technology to its potential as a near-zero emission clean coal technology by developing advanced technologies to reduce the cost and increase the efficiency of producing syngas.
The Gasification Systems Program is closely aligned with other DOE programs, and coordinates and works with other national laboratories, and private organizations to ensure that gasification R&D dovetails well with other R&D efforts, and to ensure efficient technology development with minimum cost to the taxpayer. Other program activities include educating the public about gasification and ongoing contacts and discussions with the public and industry concerning what the future of gasification should be.
Research on biomass gasification is being done by DOE's Office of Energy Efficiency and Renewable Energy (EERE). EERE's Biomass Program is working to improve gasification processes using agricultural products or useful wastes, wood and other forest products as feedstock. Goals of the Biomass Program are to promote the use of diverse, domestic and sustainable energy resources and to reduce carbon emissions from energy production and consumption. In particular, the program's focus in gasification is on improving the gasification processes for producing syngas from agricultural residues (corn stover and wheat straw) and energy crops (hybrid poplar and switchgrass) for the eventual production of ethanol.
Key remaining R&D challenges include:
- Completion of R&D for oxygen production process to create oxygen from air (ion transport membrane)
- Ensuring high-temperature trace contaminant removal system can meet proposed EPA contaminant rule, and catalyst requirements for gasoline and diesel production (synergistic requirements)
- Completion of R&D for technologies, including high pressure feed systems, uniquely suited for Western coal, since this is about half the cost (in terms of energy per pound) as high rank coal
- Developing technologies to reduce the cost of using biomass mixed with coal to reduce greenhouse-gas impact of coal-based gasification
- Creative solutions to further reduce the cost of hydrogen production
- Reduce the cost of even lower water use gasification and zero liquids discharge
Gasification R&D Around the World
Australia
The Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia's primary publicly funded research organization, is collaborating with the Cooperative Research Centre for Coal in Sustainable Development (CCSD), to operate an advanced coal gasification research facility. CSIRO has also established partnerships with other public entities and industry participants to tackle several gasification issues including researching technologies to measure coal conversion reaction processes, advancing coal and char reactivity knowledge, examining coal slag flow in gasifiers, and studying the water-gas-shift reaction in syngas processing.
Canada
The CANMET Energy Technology Centre-Ottawa (CETC-O), a R&D arm of Natural Resources Canada, represents Canada's primary gasification R&D facility. CETC-O's research involves developing gasification, syngas treating, and hydrogen production technologies.
China
The Thermal Power Research Institute (TPRI) is a Chinese research organization devoted mainly to researching technologies and equipment of fossil-fired power plants, including gasification development.
Germany
The Federal Ministry of Economics and Labor (BMWi) in Germany initiated a R&D program called COORETEC (CO2 reduction technologies) leading to a wide variety of research projects in gasification with the goal of realizing zero-emission power plants.
India
The Indian Ministry of Power operates the Central Power Research Institute (CPRI), which engages in fossil fuel gasification research. The Ministry of New and Renewable Energy performs biomass gasification research for developing rural power generation.
Japan
In Japan, the New Energy and Industrial Technology Development Organization (NEDO) is coordinating the Multi-purpose Coal Gasification Technology Development (EAGLE). This program is aimed at developing the most advanced oxygen-blown, single-chamber, dual stage, spiral-flow gasifier that can efficiently produce syngas.
South Africa
Development of fluidized-bed gasification technology at the Council for Scientific and Industrial Research (CSIR) in South Africa has been supported by the recently-formed South African National Energy Development Institute (SANEDI).
United Kingdom
The Department for Business Innovation & Skills (BIS), in the U.K. is working with the Engineering and Physical Sciences Research Council (EPSRC), the British Coal Utilisation Research Association (BCURA), industry, and international partnerships to advance gasification technology.
Other Countries
Other countries are also involved in gasification R&D to varying degrees. The links subsection offers other resources on the world of gasification research.
Coal Producers and Exporters
More precisely, slag is comprised of black, glassy, silica-based materials (a.k.a. "frit", a high density, vitreous, and abrasive material low in carbon and formed in various shapes from jagged and irregular pieces to rod and needle-like forms) and residual carbon char, the proportions of which vary depending on operating conditions, gasifier, feed, etc. The two parts can be separated—they are not chemically bonded—and concentrated into carbon rich char and vitreous frit. Char has its own current and potential uses; see the following discussion. Vitreous slag is much preferable to ash, because of its habit of encapsulating toxic species (such as heavy metals) into a stable, non-leachable material. Leachability data obtained from different gasifiers unequivocally shows that gasifier slag is highly non-leachable, and can be classified as non-hazardous. Because of its particular properties and non-hazardous, non-toxic nature, slag is relatively easily marketed as a by-product for multiple advantageous uses, which may negate the need for its long-term disposal. Obviously, both the profit from using slag as a byproduct and avoidance of disposal costs combine to improve the economics of the disposition of slag, which is the major solid byproduct from gasification processes.
In summary, the high temperatures and pressures of gasification processes have the potential to turn mineral matter within the feedstock into slag instead of the ash that is produced in combustion. Slag captures toxics/heavy metals and does not allow them to leach out of the material, unlike combustion ash from which toxic species can possibly leach and find their way into groundwater and surrounding soils.
Char
Char is the finer component of the gasifier solid residuals, composed of unreacted carbon with various amounts of siliceous ash. It can be recycled back into the gasifier to increase carbon usage and has been used as a supplemental fuel source for pulverized coal combustion. The irregularly shaped particles have a well-defined pore structure and have excellent potential as an adsorbent and precursor to activated carbon.
In a project between the Department of Energy (DOE) and CAER, potential uses of char were investigated, specifically as adsorbers for emissions control. Carbon char has the potential to control mercury (Hg) and nitrogen oxides (NOx) emissions. To test for mercury adsorption—an initial study only—a mercury vapor generator and a fixed bed reactor were used. A gas sampling system and vapor analyzer were used to assess the char’s performance. Untreated gasifier char was found to be as effective at adsorbing mercury as a commercially available activated carbon designed for Hg adsorption. Interestingly, all attempts to increase the porosity of the gasifier char lessened its adsorption potential, which seems to be related to the char mineral content (mainly SO4-2 and Cl-). Not having to treat the char is significant, as treatment would be an additional cost.
Additionally, gasification char adsorbed significantly more NOx than all other test materials except for a specially designed activated carbon NOx adsorber. For this test a thermal analyzer and mass spectrometer were used. The char performed 30% as well as the specially designed activated carbon adsorber. After increasing the surface area of the gasifier char, it increased NOx capacity, while char that was laden with Hg adsorbed more NOx than Hg-free char. This presents the possibility of using gasifier char to adsorb Hg while also adsorbing some NOx prior to an activated carbon NOx adsorber. Naturally, the gasifier char, a "waste," is significantly less expensive than a specialty adsorber and being able to put it to good use makes plant operations more economical.