Dynamic simulation of producer gas-engine operation

摘要

In the recent times, there has been a proliferation of a producer gas-engine-based power generation systems, particularly in market segments such as small enterprises and village electrification in countries such as India. The electrical load for such application is largely of inductive type, the major ones being water pumps, appliances and industrial loads. As the demand side load varies, the gas-engine generator is expected to match the demand within the shortest possible time and without large fluctuations in speed or frequency. Unlike a natural gas-fuelled engine, where fuel gas is available at the required pressure and flow rate at all times, the producer gas-engine is coupled to a biomass gasifier, and the fuel gas, i.e. producer gas, is generated on demand. Therefore, the gasifier and gas-engine form a coupled system with one mutually driving the other. The study of the coupled or integrated system becomes intriguing, particularly during transient conditions. But at the same time, the study of the coupled system is complicated, and therefore, to simplify the study, an attempt is made in this paper to model the gas-engine generator part along with the gas-fuelling system but without considering the upstream effects of the gasifier system. The behavior of the engine during steady-state and transient conditions is predicted by assuming producer gas to be available at the required pressure upstream of the engine. The results are validated against a few experimental results, and an attempt is made to explain the mismatch in a scientific manner. The need for an integrated model of the gasifier and gas-engine system has been brought out.