CoC Oral Exam Preparation (Part- 5) – Boiler

Exhaust Gas Boilers:

  • About 30% – 34% of Fuel Energy input to engine are discharged to Exhaust Gas, as Thermal Energy.
  • This thermal energy is converted into useful work in Exhaust Gas Boiler.

Cochran Exhaust Gas Boiler:
1. A double-pass, vertical type, in which Exhaust gases from ME pass through 2 banks of tube.
2. Served as an efficient silencer, when the boiler is in use.
3. A separate Silencer, always fitted along with exhaust gas boiler, to be used when the boiler is generating more steam than required.
4. All or part of exhaust gases can be directed to the Silencer and atmosphere, without going through the boiler.
5. Working Pressure is around 7 bars.

Composite Boiler (Composite type Cochran boiler):

1. If Exhaust Gases and Oil fire can be used at the same time, it is termed Composite Boiler.
2. In double-pass, composite type Cochran Boiler, it provides a separate tube nest for exhaust gas passage, situated immediately above the return tube nest from Oil-fired Furnace.
3. Exhaust gases from Oil-fired Furnace and ME; pass through the tubes, which are surrounded by boiler water.
4. Separate Uptakes provided for Exhaust Gases and Oil-fired Smoke.
5. Heavy Changeover Valves are fitted, to divert the gases straight to the funnel, when desired.
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