ThermoEnergy Corporation (OTCBB:TMEN - News) is developing a pressurized oxy-fuel approach known as the ThermoEnergy Integrated Power System (TIPS) which is a process designed to produce energy (electricity, steam) from coal, with integral carbon capture as liquid CO2 and near zero air emissions. Pressurized oxy-fuel technology addresses two major issues affecting the future use of the country’s coal resource. These are:
- Economic capture of criteria and toxic pollutants (such as mercury) from the diverse power and steam generators needed, and
- Economic capture of CO2 from the larger power and steam generators used by utilities and large industrial facilities.
Once it is commercially deployed, TIPS will revolutionize the way the world generates energy from hydrocarbons. Based on reliable oxy-fuel chemistry, TIPS departs from the traditional oxy-fuel approach by pressurizing the entire combustion system. Because the process operates at an elevated pressure it is able to use gas-to-liquid steam-hydroscrubbing to collect and remove pollutants, including NOx, SOx, mercury, particulates and CO2, and recover latent heat from water entrained or produced in the combustion process at efficiencies comparable to those of conventional large-scale combustion technologies. The pollutants are recovered via direct condensation and can be sold as commodity products. The pressurized oxy-fuel approach also enables CO2 to be recovered as a pressurized liquid through direct condensation. Emerging improvements to oxygen separation technology will significantly improve the economics of oxy-fuel processes.
TIPS PROCESS DESCRIPTION
TIPS process combustion takes place at pressures between 4.83 and 8.96 MPa. (700 and 1300 psia) Increasing the pressure of combustion shifts the temperature at which water, CO2 mercury and acid gases condense. The elevated pressure and condensation temperature process conditions enable the process to utilize heat transfer, mass transfer and liquid vapor equilibrium regimes well suited to capture of pollutants and CO2. Elevating the pressure enables the use of nucleate condensation at temperatures in the range of 262 to 303°C (503 to 577°F) in a heat exchanger that simultaneously recovers heat and condenses and captures pollutants. Two components of pressurized oxy-fuel technology central to achieving the twin goals of efficiency and pollution control are the air separation plant to provide oxygen under pressure, and the condensing heat exchanger to capture both pollutants and heat from the combustion gases.
Energy Efficiency Of The High-Pressure Oxygen Supply
Pressurized oxy-fuel firing of coal eliminates energy lost in the exhaust nitrogen by eliminating the nitrogen and recovers the latent heat of vaporization of both the produced and entrained water. In comparing the components of TIPS with a modern pulverized coal power plant, the capital cost of a conventional air separation plant used by TIPS is slightly less than the capital cost of the conventional desulfurizing unit for the pulverized coal plant.
The energy cost of separating air and pressurizing the oxygen is roughly 20% of the total energy contained in the coal. Therefore, improvements to air separation technology are especially significant to oxyfuel processes and fortunately new improvements are now entering commercial development. Emerging ion-transport membrane (ITM) technology is poised to revolutionize oxygen separation. DOE and major air separation companies estimate that capital and energy costs for oxygen separation plants will be reduced by roughly 35% compared to the traditional processes.
Condensing Heat Exchanger Recovers Heat And Captures Pollutants
The TIPS configuration enables one simple device, the condensing heat exchanger, to collect particulates, acid gases and mercury into a condensed phase that is roughly 2,500 to 3,500 times smaller than the volume of gas treated by conventional atmospheric pressure flue gas clean-up systems. The condensation heat transfer rates are so high that, once developed, the process may be less costly than current atmospheric pressure systems requiring particulate collection, desulfurizers, de-NOx and mercury abatement equipment.
TIPS enjoys numerous economic and environmental advantages when compared to conventional "clean coal" combustion technologies, such as the Integrated Gasification Combined Cycle (IGCC) process. TIPS is a straight-forward approach to power generation containing fewer unit operations and thus intrinsically more reliable. The economics of TIPS and IGCC are similar for a new large utility plants (excluding CO2 capture) using high-rank coal as a fuel. With CO2 as an added condition, IGCC cannot match TIPS economic performance in any category.
TIPS has superior projected economics for all other cases the company has examined including: subbituminous and lignite fuel, retrofit of existing coal plants, smaller power plants (5 to 100 MW), and industrial steam plants. TIPS provides the captured CO2 product as compressed liquid or solid (dry ice) ready for beneficial use or sequestration.
In the most recent U. S. Government budgeting cycle, an aggregate of $2.3 million was authorized for TIPS research and development. ThermoEnergy is currently working with its grant collaborators to use this money to expedite the development of the technology. The Company's goals are to 1) partner with a key industry participant, 2) build a prototype facility, and 3) commercialize the TIPS process.
ThermoEnergy and the University of Nevada (Reno) have successfully concluded what was the first of three federal grants designed to fast-track the development of the Company’s advanced power plant design. The subject of the work performed by the University of Nevada Reno (UNR) was conducted under the US Department of Energy’s Biomass To Energy Program. The engineering data gathered during this research program will be added to the data gathered via the remaining two grants – a $300,000 DOE grant, previous post, and a $1,500,000 grant with the Alaska Energy Agency – which will allow the Company to design a large-scale TIPS demonstration plant.
The Company, along with the EPA Grant Administrator and the Alaska Energy Agency (AEA), made the decision to allocate most of the upcoming $1.5M federal grant toward the design, building and operation of the first working prototype of a TIPS power boiler. This system will be housed at the Canadian Energy Laboratory (part of CANMET) in Ottawa. AEA recently received notification from the US EPA that the grant application has been approved and will be funded pending notification of the members the State of Alaska congressional delegation. This prototype is expected to demonstrate TIPS zero air emission capability, along with CO2 capture and provide the engineering data necessary to design and build a large-scale demonstration unit.
Alex Fassbender, SVP for Engineering and Technology Development for ThermoEnergy, presented a technical paper on the TIPS process at the recently held 30th International Technical Conference on Coal Utilization & Fuel Systems, which can be found here.
ThermoEnergy Corporation, Little Rock, AR