Gasification Process Using Downdraft Fixed-Bed Gasifier for Different Feedstock

Abstract

The use of conventional fuels is decreasing globally due to its limited reserves and negative impact on the environment. The associated cost of conventional fuels is increasing owing to the higher demand for conventional fuels. Hence, utilization methods of biomass to generate energy are of growing interest. Among different biomass feedstocks, rice husks, waste plastics, and sawdust are significantly available in the global environment. The annual generation amount of rice husk is approximately 120 million tons worldwide, with an annual energy generation potential of 109 GJ with a heating value of 15 MJ/kg. The gasification process is assumed to be the most effective biomass conversion method that can generate synthetic gas to operate IC engines, fuel cells, and boilers. Synthetic gas production from biomass using a gasification process is a significant source of future energy. Downdraft fixed-bed gasifiers are considered as a feasible option of biomass conversion in the gasification process. By optimizing the operating conditions of downdraft fixed-bed gasifier, such as reaction zone temperature, combustion zone temperature, intake air temperature, airflow rate, the humidity of intake air, a significant amount of synthetic gas can be produced from rice husks, waste plastic material, and sawdust.

A comprehensive review of primary strategies for tar removal in biomass gasification

“…Nevertheless, fluid beds have usually much shorter residence times. Regarding entrained bed gasifiers, they have a very short residence time, even lower than fluidized beds [207]. Spouted beds are also characterized by short residence times, below 0.5 s. Erkiaga et al [44] showed that tar cracking and reforming was limited (very high tar concentration in the gaseous stream) in the biomass steam gasification carried out in a conical spouted bed reactor.…”

A Review of Factors Affecting Gasifier Performance

“…It has been found that downdraft gasifiers can handle feed with moisture content up to 25% and the upper limit of moisture content that an updraft gasifier can handle is 50 % [35]. It is proposed that in FBG, for maintaining fluidization state, and temperature profile conditions, the feed rate should be low for high moisture content fuels.…”

Study on the Process of Gasification of Black Liquor

“…The heat from combustion removes moisture from the BL as well as other particles from the pyrolysis zone. However, it is important to note that the temperature must reach > 800 °C in the reactor to produce gas (Hoque and Rashid, 2021). Pressure gasification of BL at high temperature is a potential complement to the recovery boiler traditionally used to recover chemicals and energy from the BL in the Kraft pulping process.…”