Experimental and Numerical Investigation of the Argon Power Cycle

Abstract

Carbon capture has been deemed crucial by the Intergovernmental Panel on Climate Change if the world is to achieve the ambitious goals stated in the Paris agreement. A deeper integration of renewable energy sources is also needed if we are to mitigate the large amount of greenhouse gas emitted as a result of increasing world fossil fuel energy consumption. These new power technologies bring an increased need for distributed fast dispatch power and energy storage that counteract their intermittent nature. A novel technological approach to provide fast dispatch emission free power is the use of the Argon Power Cycle, a technology that makes carbon capture an integral part of its functioning principle. The core concept behind this technology is a closed loop internal combustion engine cycle working with a monoatomic gas in concert with a membrane gas separation unit. By replacing the working fluid of internal combustion engines with a synthetic mixture of monoatomic gases and oxygen, the theoretical thermal efficiency can be increased up to 80%, more than 20% over conventional air cycles. Furthermore, the absence of nitrogen in the system prevents formation of nitrogen oxides, eliminating the need for expensive exhaust gas after-treatment and allowing for efficient use of renewable generated hydrogen fuel. In the case of hydrocarbon fuels, the closed loop nature of the cycle affords to boost the pressure and concentration of gases in the exhaust stream at no penalty to the cycle, providing the driving force to cost effective gas membrane separation of carbon dioxide. In this work we investigated the potential benefits of the Argon Power Cycle to improve upon current stationary power generation systems regarding efficiency, air pollutants and greenhouse gas emissions. A cooperative fuel research engine was used to carry out experiments and evaluate engine performance in relation to its air breathing counterpart. A 30% efficiency improvement was achieved and results showed a reduction on engine heat losses and an overall increase on the indicated mean effective pressure, despite the lesser oxygen content present in the working fluid. Greenhouse gas emissions were reduced as expected due to a substantial increase in efficiency and nitric oxides were eliminated as it was expected. Numerical simulation were carried out to predict the performance and energy penalty of a membrane separation unit. Energy penalties as low as 2% were obtained capturing 100% of the carbon dioxide generated.