Understanding Products of Thermo-Chemical Processes

The resulted products after any thermo-chemical process are:

• A solid elements (residue), known as char

• A gas product( syn gas)

• A tarry liquid of compound composition, familiar as “tar”, often present in liquid vapour phase at process temperature

As per the reported by Hallgren et.al. (1996), the uniqueness of the products like as gas, liquids and solid, based on a broad range of factors just like as the chemical as well as physical distinctiveness of the feedstock, the heating rate (C.V), the preliminary and final process temperature, pressure and finally type of reactor.

1.2.1 Pyrolysis or De-volatilization

Pyrolysis is the process which is thermal dispossession of biomass in the lack of an oxidizing cause at 300-500 °C. The term de-volatilization

al. 1996). this dense produce is more thermally unbalanced than mulch or coal, mainly as of grass biomass. Little warming degrees and extensive residence eras will decrease the reactivity of the burn. On the other hand, great heating rates give to upsurge the reactivity of the subsequent char, creating it advanced appropriate for more thermal usage for example gasification or combustion (Hallgren, et. al. 1996).

The character of the residual char be contingent very on the pyrolysis circumstances, specifically known as heating rate and concluding pyrolysis heat. Consequently, the pyrolysis circumstances are some of the greatest significant constraints when learning or examining char reactivity and char pore development.

1.2.2

The gasification in presence of air produces a low calorific value gas (LCV) of about 4000-7000 KJ/Nm3 (Higher Heating Value) though gasification in the presence of oxygen produces to an average calorific value gas (MCV) of 12000-18000 KJ/Nm3 (HHV). Oxygen gasification process is a very expensive process. The over-all biomass gasification process is depicted in Figure 1.6.

In the production process of chemicals it requires to use of a average calorific value gas (MCV) also non-nitrogen diluted by minor impurities for best alteration to chemical compounds (Paisley et al., 1994). For the electricity production the used product gas should be clean from char-particles, pitch and ash etc. before it is inserted into the gas turbine or in a combustion engine. The higher temperature gases which exits from the gas turbine can be further used to generate steam from there heat for a steam turbine, like as an Integrate Gasification Combined Cycle (IGCC) generally used in power