Peformance of gasifier-engine system
Cold gas efficiency of producer gas in favourable condition can be
70%. In gasifier-engine system, losses also occurs at different stages. Engine
performance is expressed in terms of brake thermal efficiency. Overall
efficiency of the system is the product of gasifier efficiency and brake thermal
efficiency.
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The actual efficiency of engine varies with design, size and
running condition. Efficiency of diesel and gasoline engines under good
condition are considered to be 30% and 20% respectively. The efficiency of
engine run with producer gas goes down owing to lower density of gas-air mixture
and other power losses associated with suction of mixture in engines.
Theoretically, gasoline and diesel engine operated on producer gas suffer a
power loss of 30% and 20 % respectively. In practice, considering a wide range
of producer gas quality, a power drop ranging from 25 % to 60 % can be expected
when diesel or gasoline engine is run with producer gas
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A typical composition of 4.5% CO 2 , 27 % CO, 14%
H2 , 3 % CH 4 and 51% N 2 has a lower heating
value of 5.7 MJ/m3 at normal ambient condition of 15o C
and pressure of 1 atm . The stoichiometric gas-mixture has an energy density of
2.5 MJ/m3 compared to 3.5 MJ/m 3 for gasoline-air mixture
and 3.3 MJ/m 3 diesel-air mixture.
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