Etude de la combustion de gaz de synthèse issus d'un processus de ...

Chapter 2
o Oxygen;
o Steam;
o Other gases containing oxygen, such as CO 2 (Gañan et al., 2005).
Gasifier heating:
o Direct ;
o Indirect.
Heating value (McKendry, 2002b):
o
o
o
Low: 4 -6 MJ/Nm 3 (using air or air / steam);
Medium: 12 -18 MJ/Nm 3 (using oxygen and steam);
High: 40 MJ/Nm 3 , using hydrogen and hydrogenation.
tel-00623090, version 1 - 13 Sep 2011
2.1.3 Gasification plant
A gasification plant consists into three main units (McKendry, 2002a):
o Gasification unit – the reactor,
o Cleaning unit - filtration and cooling, and
o Energy conversion unit.
These are briefly described in the following sections.
2.1.3.1 Gasifier types
A variety of biomass gasifier types have been developed. They can be grouped into
four major classifications: fixed-bed updraft, fixed-bed downdraft, bubbling fluidized-bed
and circulating fluidized bed. Differentiation is based on the means of supporting the
biomass in the reactor vessel, the direction of flow of both the biomass and oxidant,
and the way heat is supplied to the reactor (Rampling and Gill, 1993). Table 2.1 lists
the most commonly used configurations.
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