Canadians aim to capture lower CCS costs1 July 2008
Cost reduction is a key goal for those in the business of developing technologies for the capture of carbon dioxide and this generally amounts to minimising energy requirements and therefore the efficiency penalty that capture inevitably entails when installed on a power plant.
One company claiming to be making good headway in this direction is HTC Purenergy of Regina, Saskatchewan, Canada, who describe their Thermal Kinetics Optimization (TKO) process as nothing less than a “CO2 capture cost reduction breakthrough.” TKO will be added to their existing Purenergy CCS post combustion capture system and “will substantially reduce the energy requirements of capturing CO2 from...coal and natural gas power plants.”
HTC Purenergy says “the TKO process improves the CO2 capture system through heat recovery, thermal balancing and optimised process flow.” The primary advantage of the newly patented system is that it directly reduces the largest single cost of most post combustion capture systems – the use of power plant steam – to a ratio of below 1 unit steam required to 1 unit CO2 captured.
The TKO process has been shown to reduce steam consumption by up to 30%, says HTC Purenergy, which is a major step towards driving down the cost of CO2 capture compared with existing commercial technologies.
Another cost reduction route which HTC Purenergy is actively pursuing is to derive the energy for carbon capture from waste coal and methane by making use of a technology called the Hybrid Coal Gas Turbine (HCGT), which is being developed by EESTech of Brisbane, Australia.
The HCGT employs a rotating kiln, which has high thermal inertia and long retention times, making it tolerant to fluctuations in fuel quality and able to handle low grade fuels. The hot exhaust gas is fed to an HRSG to generate steam and drive a turbine generator.
HTC Purenergy estimates that the EESTech process could reduce the cost of capture by about 25%, on top of the 30% or so promised by TKO.
HTC Purenergy, EESTech and Santos (Australian oil and gas exploration and production company) have entered into an agreement to explore business opportunities for carbon capture, storage and enhanced oil recovery at depleted fields belonging to Santos.
Santos says the idea is to build on its current development activities focusing on the Moomba Carbon Storage Project, which has the long-term objective of establishing a large-scale carbon storage hub at Moomba. This could eventually store up to 20 million tonnes of carbon dioxide per year and 1 billion tonnes over the life of the project.
Carbon dioxide would be injected into the depleted and/or depleting oil and gas reservoirs of the Cooper Basin, thereby providing a secure storage solution for major carbon emitters in Queensland, New South Wales and South Australia, as well as stimulating further gas flow from the field.
The agreement with Santos followed the announcement by HTC Purenergy of a feasibility study with Loy Yang Power, which operates a 2200 MW brown coal fired power station in Australia’s Latrobe Valley.
EESTech is also involved in this agreement since, as well as being developer of the HCGT technology, it has the licensing rights for deployment of HTC Purenergy’s technology in Australasia.
HTC Purenergy describes its technology, which is designed to be retrofittable to existing power plants, as the “world’s first pre-engineered, pre-built and modularly constructed CO2 capture system.” The Pureenergy CCS 1000 (pictured above) is designed to capture 1000 t/d of CO2.
The system will form the basis for a FEED (front end engineering and design) that HTC Purenergy is submitting (together with its consortium partner Bechtel) for the European CO2 Test Centre Mongstad in Norway.
HTC Purenergy (with Bechtel) has also been qualified to provide a FEED for full scale CCS at the Kårstø combined cycle plant, again in Norway. Also participating in this project are Aker Clean Carbon, Fluor Daniel and MHI.
Much closer to home, the company’s technology seems well placed to be selected by SaskPower for its planned 100 MW CCS demo project at its Boundary Dam coal fired plant. This will involve rebuilding and repowering one of the units and equipping it with CCS.
In fact, the Purenergy technology is already installed at Boundary Dam, in a small-scale 4t CO2/d extraction demonstration plant. It has also been tested on a smaller pilot plant at the University of Regina, Saskatchewan.
The new TKO process has been trialled on this pilot plant and is to be subjected to 3000 h of verification testing on the Boundary Dam demonstration plant.
HTC Purenergy’s mission is to commercialise technology developed over the last twenty years or so (initially for EOR applications) at the University of Regina and at the university’s International Test Center for CO2 Capture (ITC).
In addition to HTC Purenergy, ITC’s sponsors include SaskPower, E.ON, Saudi Aramco, Research Institute of Innovative Technology for the Earth (RITE), Alberta Energy Research Institute, Neill & Gunter, Babcock & Wilcox, Natural Resources Canada, and Saskatchewan Industry & Resources.
HTC Purenergy signed a licence agreement with Doosan Babcock for a project submission to the UK government’s CCS competition. The project envisages retrofitting Scottish Power’s Longannet power plant with supercritical boiler technology and adding CCS. But it is understood that Aker Clean Carbon was eventually selected as the capture technology supplier.