Biofuels from Lignocellulosic Biomass

Solid lignocellulosic biomass can be converted into liquid fuels by first generating a gas from the solid feedstock, called product gas. This product gas is then purified to produce synthesis gas, which consists of a variety of components and can be used directly for energy production. The main components of synthesis gas are primarily carbon monoxide (CO) and hydrogen (H₂).

In the second step, this synthesis gas is converted into liquid products through various processes, such as Fischer-Tropsch synthesis. The combination of gasification and subsequent Fischer-Tropsch synthesis is referred to as the BtL process (Biomass-to-Liquids). In the following, we will first take a detailed look at the processes used to produce synthesis gas from solid feedstocks. Fundamentally, there are two ways to produce synthesis gas:

• Gasification (thermochemical conversion of biomass)
• Biogas production (biochemical conversion of biomass)

Since the latter option is better suited for moist organic waste, we will focus here on the processing of lignocellulosic feedstocks (wood gasification). For information on hydrothermal gasification, please refer to the further reading section. For the first step, there are several approaches to obtaining gas from the feedstocks. On the following pages, you will learn more about:

• Gasification of solid biomass
• Fixed-bed gasifiers
• Downdraft gasifiers
• Fluidized bed gasifiers
• Entrained-flow gasifiers