OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
Q biomass = m biomass X CV biomass
And Q producer gas = m producer gas X C P producer gas X ∆T
Where, m biomass is biomass consumption rate in kg/h, C P producer gas is average specific heat is in kJ/kgK and ∆T
is temperature difference between producer gas and environmental air. When the gasifier ran at the full load then
the following parameters were found: m biomass =56kg/h, m producer gas = 170 m 3 /h, ∆T= 9 0 C and C P producer gas =
1.232 kJ/kg 0 C.
Fig.4 shows the energy flux diagram for engine gen-set in which the producer gas from gasifier was used in the
internal combustion engine. At the full load operational condition; the electric load produced is of 25kW
capacity, that measured by using of loading device fitted with heaters 3kW each ,the total stack gases thermal
power was 25kW at 400 0 C.Initally this power was totally wastage but after some combination of cycles, this
could be utilized. Such like this, the heat losses were in the engine jacket of about 25kW at 92 0 C. By considering
the cooling water energy of internal combustion engine in the jacket is a potential for using this thermal energy
for the heating purposes. At least 5kW was the accounted loss and it is compulsory to overcome frictional losses
so these are the unaccounted losses or can’t be recovered and the following models were used in the above
calculations:
P = √3 VI for star connection
Q exhaust gas = (m a + m pg ) X Cp exhaust gas X ∆T
Q Jacket = m Jacket X C P water X ∆T
Q unaccounted = Q producer gas – (P + Q exhaust gas + Q Jacket )
Where (m a + m pg ) is the mass flow rate of exhaust gases in kg/h, m Jacket is the mass flow rate of water in kg/h,
Cp exhaust gas is the specific heat of the exhaust in kJ/kg K, C P water is specific heat of water in kJ/kg K, V is voltage,
I is current in ampere and ∆T is temperature difference while Q unaccounted is showing the frictional losses in genset.
At the full load, electric power is 35 kW, mass flow rate of exhaust is 300kg/h and specific heat of exhaust
gases is 1.008kJ/kg K. This system may be an advance system and ornamented with some modern technology.
Now a days, the combined cycle’s plants are being generated for utilization of waste or stack or exhaust gases. In
this technology exhaust gases give the heat to generator through heat recovery unit at 400 0 C apart from the
heating by engine jacket , these gases can be used for this purpose after all.
Cooling 51.7% (cooling
capacity 15kW, COP
0.517)
Exhaust
gases
100%
(25kW
&4kWe)
Pump 13.79%
(4kWe)
Losses 34.48%
(10kW)
Fig.5. Energy flux diagram for VAM
Fig.5 shows the utilization of thermal power of stack gases which are at 400 0 C. About 15kW was effectively
transformed into cooling load by absorption chiller (C.O.P =0.517 in this case) at temperature of the cold storage
between 0 0 C – 5 0 C. About 40% losses of stack gases heat was due to design consideration of absorption
chiller machine .13.79% of energy was utilized in running of the pump of VAM. In a gasifier gen-set power
plant, there were the 62.5% losses. 31.25% losses of which were totally wastage. This wastage could be used in
20