Stationary compression ignition internal combustion engines (CI-ICE) CO2 capturing via microalgae culture using a mini-photobioreactor

This paper presents the development and analysis of a multigeneration system prototype associated with microal-gae culture for biomass production. The system was designed to recover waste heat from the compression ignition internal combustion engine (e.g., diesel engine) and to capture CO₂ in its emissions for microalgae growth. Two algae species, Scenedesmus sp. and algae mixture from a local park in Curitiba, were separately cultured in a 20 L-jug by supplying two distinct CO₂ sources: air and diesel engine emissions. Subsequently, microalgae growth rates were determined from absorbances and analyzed to construe whether emissions in lieu of air enhanced the microalgae growth. Similarly, mini-photobioreactor (mPBR) was employed to culture local algae mixture with air and emissions as CO₂ sources, to assess the practicality of using mPBR for microalgae culture compared to traditional methods. In addition to microalgae culture, a thermodynamic analysis of the multigeneration system was performed to examine the effects of waste heat recovery and biomass production on the overall system efficiency. According to the analysis, the system efficiency increased by 13.55% with waste heat recovery and the use of biodiesel obtained from microalgae. Furthermore, experimental results proved increased biomass production using diesel engine emissions, and PBR was determined to be more effective than tanks or ponds for microalgae culture. As a result, this work verified the possible use of CO₂-rich diesel engine emissions for microalgae culture using mPBR and waste heat recovery for an improved multigeneration system free of greenhouse gas emissions.