In our power plant, we pay special attention when the subject of Heat Rate comes up.
The exhaust gases of some engines are used to generate steam in waste heat boilers. This steam heat up the Heavy Fuel Oil.
First of all, it is necessary to establish a benchmark Heat Rate for each engine. Then, determine the actual performance of each engine.
In order to maintain the Heat Rate (to improve it comes later), we dedicate a particular effort controlling the following:
- Cleanliness and pressure drop of the intake air filters.
- Charge air temperature and pressure. This temperature and pressure are dependent of the inter coolers proper operation.
- Fuel injection system works properly. Special controls are applied to the fuel injection pumps adjutments and fuel injectors calibration.
- The fuel oil treatment system works perfectly.
- Instruments assessment. Probably, this is one of the most important items.
All these controls (among others) have an unique purpose: to supply the engine with an air and a fuel oil with the temperature, pressure, viscosity and quantity appropriated for a good combustion; because, do not forget that the Heat Rate is dependent of the Specific Fuel Consumption (SFC).
If you use distillate fuel then heat recovery will be of little value, and if you use HFO you probably have heat recovery already. If so I'm sure there will be a few 'small' steam leaks which don't look bad but will actually be dropping your overall plant efficiency. Also, keep on top of your water chemistry.
What type of engines do you have and what is their age/running hours? It might be worth upgarding them with new turbochargers, charge air coolers, cams, injection system etc but if they are very old engines the cost of such an upgrade may not pay for itself through better heat rate before you retire the plant.
21121956 gives excellent advice: keep your plant in the best condition you possibly can - NEVER neglect your maintenance.
