Biomass Gasification Essay

Biomass gasification is a process by which biofuel is produced. It has been used for over 180 years but in the last decades it has been reconsidered as an interesting technique due to the fact that oil supplies are decreasing. As mentioned before, gasification is a thermal process. Heat is added up in order to convert the organic mass to biofuel. The biomass usually undergoes drying, pyrolysis, partial oxidation and reduction. Nowadays the configurations used for gasification are three: fixed bed gasifier, fluidized bed gasifier and entrained bed gasifiers. The simplest configuration is the

Biosyngas composition
Gasification products can be divided in fuel gases and non-fuel gases. The fuel gas (mixture of Carbon monoxide, Hydrogen and traces of Methane) is called producer gas. In particular, section 2.2 focuses on the non-fuel gases such as Carbon dioxide, Nitrogen, some hydrocarbons and water steam which cannot be utilized for combustion. Table 1 shows that according to the gasifier system and the gasifier agent, the biogas composition

2 Fast Internally Circulating Fluidized Bed. 3 Dual Fluidized Bed. 4 Bubbling Fluidized Bed Gasifier. *Dry basis
2.2. Secondary products
All different kinds of secondary products are discussed in these section such as particulate matter (section 2.3.1), Tar compound (section 2.3.2), Sulphur compound (2.2.4). Although not much literature is available, section 2.3.3 briefly introduces the importance of Alkaline, heavy metals and halides compounds as secondary products. It is worth mentioning that secondary products come out from the gasification process concentrations of which in the gas depend on the biomass composition and the technology used.
Table 2 summarizes the typical concentrations of secondary products in biosyngas.
Table 2. Typical content impurities in biosyngas [25, 26]

Nitrogen
(ppmv) Sulphur
(ppmv) HCl
(ppmv) Alkali metals
(mg/kgbiomass ) Tars
(g/Nm3) Particles
(g/Nm3)
2000-6000 100-1000 30-500 600-4000 0,01-100 8-100