Application of Thermochemical Fluids as a Sustainable Energy Source in Steam Engine

Thermochemical fluids of an exothermic nature are a good source of pressure and temperature and have been recognized for their application for enhanced oil recovery, wellbore stimulation, and condensate banking removal. However, these chemicals can also be utilized as an energy source to add to steam engines. Conventional steam engines rely on boilers fueled by coal, wood, or oil to heat water into steam. This study explores the possibility of replacing steam with thermochemical fluids in steam engines to drive a turbine and generate electricity. The aqueous solution of ammonium chloride and sodium nitrite was used as thermochemicals which reacts to generate salt, water, and nitrogen gas in a closed cell. This reaction is highly exothermic and generates high-pressure nitrogen gas measured by a pressure probe. The hot nitrogen gas is then fed to the Steam Engine Model Kit (limited to 14 to 45 psi air pressure) at 14.7 psi, which generates mechanical work that can be used to drive a generator and produce electricity. The total time and the Rotation Per Minute (RPM) of the engine were measured with a tachometer to calculate the power generated for the given amount of thermochemicals and measured its energy efficiency. The key findings show that when 30 mL of both chemicals reacted in an 80 cm³ closed cell, high-temperature nitrogen gas was generated with pressure increasing with time. The peak pressure in the cell was found more than 1765 psi after the reaction. This pressure was then utilized to generate the energy through the engine and to calculate its efficiency. Compared with steam, these thermochemicals are more stable and do not experience phase change (such as boiling or condensation) which can reduce the efficiency of the steam engine. Furthermore, these thermochemical fluids generate non-corrosive nitrogen to drive the engine which results in lower maintenance requirements and longer service life for the engine. In summary, an exothermic reaction generating nitrogen (working fluid) can run a turbine to generate mechanical work and produce electricity.