The High Pressure Oxy-Fuel (HiPrOx) process is a natural evolution of the ambient oxy-fuel process. Motivated by the well understood thermal dynamic advantages of high pressure and based on rich industrial experience, HiPrOx uses oxygen to combust fuels at elevated pressures in a boiler. The HiPrOx process consists of mostly off-the-shelf industrial components; including furnaces, steam/gas heat exchangers, air separation units (ASU), and pumps. In addition, two condensing heat exchangers are employed to recover flue gas latent heat and to liquefy CO2.
CanmetENERGY conducted a comprehensive technical and economic feasibility study of HiPrOx. The study concluded that high pressure oxy-fuel combustion can lead to:
- Increased boiler efficiency by approximately 10% compared with ambient air and oxy-fuel technologies as a result of efficient latent heat recovery
- Increased steam cycle efficiency by approximately 8% compared with ambient cycles due to heat duty savings at feed water heaters
- Reduced auxiliary power consumption by approximately 35% compared with ambient oxy-fuel cycles attributed to product recovery train and air pollution control devices
- A savings of approximately 10% in auxiliary power with the elimination of multi-stage compression and refrigeration required in ambient oxy-fuel technologies
- Improved fuel burnout for a similar residence-time furnace operating at ambient pressure
- Significant reduction in furnace and heat exchanger sizes
- HiPrOx cycle efficiency being less influenced by high moisture fuels (e.g. lignite, biomass)
- Improved effectiveness of scrubbing for air pollution control
- Reduced sizing of the scrubber and flue gas condenser compared with ambient pressure technology
- Significantly improved capital and operating economics over existing power generation with carbon capture technologies
HiPrOx provides an opportunity to generate competitively priced power, using a wide range of fuels. At the same time, the process captures CO2, reducing the negative environmental impacts associated with conventional power generation. The cost of electricity associated with CO2 capture for air-fired combustion with amine scrubbing or ambient pressure oxy-fuel are more than 60% higher than without capturing CO2. However, these costs are only about 25% for HiPrOx.
CanmetENERGY is actively searching for partners to further advance the HiPrOx technology. In the immediate future, a back-end portion of a HiPrOx pilot plant will be designed at our facilities to study gas and liquid properties, solids segregation, CO2 capture, and heat transfer under various operating conditions. In addition, detailed furnace and boiler designs will be carried out with the aid of cold flow modeling and scaling methods as next step.
We are seeking support and funding to construct a fully functional pilot-scale HiPrOx test facility. Discussions are currently under way with various potential government agency, industrial and university partners to form a pressurized oxy-fuel combustion consortium to further develop the HiPrOx process and to advance its business case.
Table 1 - Approximate relative costs of subcritical coal-fired technologies for power generation (bituminous or subbituminous coals).
Table 2 - Approximate thermal efficiencies of subcritical coal-fired technologies for power generation (bituminous or subbituminous coals).
To find out more about the HiPrOx process, or to diccuss partner opportunities, please contact us.