All CHP plant requires effective and reliable monitoring and maintenance to provide the required levels of reliability and efficiency.
The following explains what is involved in the maintenance of CHP plant. However, this is normally part of an O&M contract and does not involve on-site staff beyond their being informed that service staffs are on site.
For a packaged CHP unit, relatively little routine maintenance is needed to allow the unit to operate continuously for long periods. Provided that supplies of fuel, water and air to the engine are kept at their required conditions, the unit should require maintenance attention at the planned service intervals. Regular brief visual checks by site staff are the only tasks required during operating periods. The rest are done by the O&M contractor.
However, a CHP plant may experience a slight degradation in output and efficiency between the stoppages for scheduled servicing. This is almost entirely caused by the gradual wear of components in the engine: spark plugs, in particular, require regular attention and replacement to maintain engine performance. Other items that need regular attention include air filters, valve clearances and turbocharger operation.
A considerable amount of information on plant condition can also be obtained by the regular sampling and analysis of engine lubricating oil. The presence of water or other liquid contaminants, or of metallic or non-metallic solids, provides an indication of excessive wear or leakage, while the condition of the oil itself, such as its acidity and viscosity, gives valuable information on engine condition. It is common practice to take regular samples, which are sent for testing.
Schedules of typical maintenance requirements are available, however in practice this work is carried out by the maintenance company according to a schedule derived from engine data.
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