A dual fired downdraft gasifier system to produce cleaner gas for power generation: Design, development and performance analysis

• Hot air injection in dual fired reactor reduces the tar content to less than 100 mg Nm−3.
• In clean gas the tar content is 35 mg Nm−3 and the dust content is nil.
• The specific gasification rate is 2.8 Nm3 kg−1 of fuel wood and cold gas efficiency is 89.7%.
• CV of the gas: 5.3 MJ Nm−3, SFC: 1.1 kg kWh−1 and wood to power efficiency: 21%.
• Cold gas efficiency is improved by optimizing the reactor's design and recycling the waste heat from hot gas.

The existing biomass gasifier systems have several technical challenges, which need to be addressed. They are reduction of impurities in the gas, increasing the reliability of the system, easy in operation and maintenance. It is also essential to have a simple design of gasifier system for power generation, which can work even in remote locations. A dual fired downdraft gasifier system was designed to produce clean gas from biomass fuel, used for electricity generation. This system is proposed to overcome a number of technical challenges. The system is equipped with dry gas cleaning and indirect gas cooling equipment. The dry gas cleaning system completely eliminates wet scrubbers that require large quantities of water. It also helps to do away with the disposal issues with the polluted water. With the improved gasifier system, the tar level in the raw gas is less than 100 mg Nm−3.Cold gas efficiency has improved to 89% by complete gasification of biomass and recycling of waste heat into the reactor. Several parameters, which are considered in the design and development of the reactors, are presented in detail with their performance indicators.