Optimization of operation strategies of a syngas-fueled engine in a distributed gasifier-generator system driven by horticulture waste

Abstract

This work optimized the operation of a syngas-fueled spark ignition (SI) engine in the gasifier-generator (GG) system to achieve improved combustion performance and reduced emission adapting to the electrical power output. The combustion performance and emissions of the SI engine were modeled by an experimentally validated 3D KIVA4-CHEMKIN model with a detailed GRI 3.0 mechanism. Effects of the ignition timing (IT), fuel–air equivalence ratio (FAER), inlet temperature, and power load on the energetic, knock and environmental performance of the SI engine were investigated by analyzing the in-cylinder pressure, heat release, indicated thermal efficiency (ITE), NOx emission, peak temperature and maximum pressure derivative (MPD). When IT increases from 14 to 50 crank angle degrees (CAD) before top dead center (BTDC), the ITE first increases and then decreases, while the NOX emission, peak temperature, and MPD keep increasing. In the range of IT from 14 to 50 CAD, FAER from 0.5 to 0.9, inlet temperature from 300 to 407 K, potential space of optimization variables was figured out in the phase diagram of NOx emission vs. ITE at each power load of 4–10 kW. The optimal IT, FAER, and intake air temperature parameters were selected from the Pareto front of the potential optimization space using the ideal point method. The results show that the load-related control strategy can achieve high ITE values of 39.01–39.69% and satisfactory nitrogen oxide emissions of 0.6–1.55 g/kWh. The optimization method and optimal operation parameters provide references for improving engine performance in the GG system.