Thermopac is a oil fired furnace which uses heat of combustion of fuel to heat thermic fluid.
Thermic fluid is used in processes, heating up to high temperatures for which steam becomes too costly because of the high pressure requirement to reach high temperature. Helps in achieving high temperature at low pressure and enhances the system safety. The system is easy to operate as there is no water treatment and chemical dosing involved. No heat loss to the atmosphere through traps and leaks as steam systems do.
- Fuel is burnt with oxygen gives the energy,
- Air is cheapest source of Oxygen which contains 21 mol % O2,
- Drawback of air utilization is the presence of nitrogen 79 mol % of air,
- Nitrogen reduces the flame temperature considerably and also accounts for high heat loss to the stack.
- Theoretical air is not sufficient to get complete combustion.
- Incomplete combustion gives Carbon monoxide and Carbon.
- Excess air supply is must for complete combustion to avoid formation of CO and coke formation.
- The actual excess air depends on the fuel used for combustion. For gaseous fuels 5 to 15% and liquid and solid fuels 10 to 50%.
- Effect of excess air : Reduced flame temperature and increased heat losses through the flue gases.