Page 48 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory

Chapter | 1 Introduction 27

1.6.7 Ammonia Synthesis
Ammonia (NH 3 ) is an important feedstock for fertilizer production. It is
produced from pure hydrogen and nitrogen from air:
3H 2 1 N 2 ðcatalystsÞ-2NH 3 92; 000 kJ=kmol (1.13)

1.6.8 Fischer Tropsch Reaction
The Fischer Tropsch synthesis reaction can synthesize a mixture of CO and
H 2 into a range of hydrocarbons, including diesel oil:
2n H 2 1 nCO 1 catalyst-ðC n H 2n Þ 1 n H 2 O 2 Q (1.14)
Here, C n H 2n represents a mixture of hydrocarbons ranging from methane
and gasoline to wax. Its relative distribution depends on the catalyst, the tem-
perature, and the pressure chosen for the reaction.

1.6.9 Methanation Reaction
Methane (CH 4 ), an important ingredient in the chemical and petrochemical
industries, can come from natural gas as well as from solid hydrocarbons
like biomass or coal. For the latter source, the hydrocarbon is hydrogenated
to produce synthetic gas, or SNG. The overall reaction for SNG production
may be expressed as:

C 1 2H 2 -CH 4 74; 800 kJ=kmol (1.15)

More details on these reactions are given in Chapter 7.

SYMBOLS AND NOMENCLATURE

LHV lower heating value of gas (kJ/mol)
η efficiency of different components as indicated in example 1.1
inlet steam temperature in the steam turbine (K)
T 1
exhaust steam temperature in the steam turbine (K)
T 2
inlet temperature in the gas turbine (K)
T g1
exhaust temperature in the gas turbine (K)
T g2