燃气涡轮工程手册 Gas Turbine Engineering Handbook 3(46)

曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

A change in approach is clearly necessary in order that the full benefit of integrated plant condition management and control can be recognized and exploited. Improved control and enhanced performance monitoring will enable shutdown intervals to be extended without increasing the risk ofpremature or unexpected failure. Inturn， this will increase the confidenceof operations， inspection and management personnel in the effectiveness of unified plant administration.
Life Cycle Costs
The life cycle costs of any machinery are dependent on the life expectancyof the various components， the efficiency of its operation through out its life.Figure 19-9 shows the cost distribution by the three major categories， initialcosts， maintenance costs， and operating or energy costs. This figure indicatesthat the new costs are about 7-10% of the life cycle costs， while maintenancecosts are approximately 15-20% of the life cycle costs and operatingcosts，which essentially consist of energycosts， make up the remainder between 70-80% of the life cycle costs of any major machinery in a utilities plant.
10%

Initial Cost Maintenance Cost Energy Cost
It is therefore clear why the new purchasing mantra for a utilityplant， or forthat matter offact， for any major plant operating large machinery is ..life cycle cost...
This brings forth to the forefront performance monitoring as an essential tool in any type of plant condition monitoring system. The major costs in a life cycle are the cost of energy. Thus operating the plant as close to its design conditions guarantees that the plant will reduce its operating costs. This can be achieved by ensuring that the turbine compressor is kept clean and thatthe driven compressor is operating close to its maximum efficiency， which in many cases is close to the surge line. Thus knowing where the compressor is operating with respect to its surge line is a very critical component in plant operating efficiency.
The life expectancy of most hot section parts is dependent on various parameters and is usually measured in terms of equivalent engine hours. The following are some of the major parameters that effect the equivalent enginehours in most machinery， especially gas turbines:
1. Type of fuel.

2. Firing temperature.

3. Materials stress and strain properties.

4. Effectiveness of cooling systems.

5. .umber of starts.

6. .umber of trips.

Maintenance practices are being combined more and more with opera-tional practices to ensure that plants have the highest reliability with max-imum efficiency. This has led to the importance of performance condition monitoring as a major tool in the operation and maintenance of a plant. .ifecycle costs， rightlyso， now drive the entire purchasing cycle and thus the operation of the plant. .ife cycle costs， based on a 25-yearlife， indicate that the following are the major cost parameters:
1.  Initial purchase cost of equipment is 7-10% of the overall life cycle cost.

2.  Maintenance costs are about 15-20% of the overall life cycle cost.

3.  Energy costs are about 70-80% of the life cycle costs.

This distribution in life cycle costs indicates that component efficiency throughout the life period of the plant is the most important factor affectingthe cost of a particular machine train.Thus， monitoring the efficiency of the train and ensuring that degradation rates are slowed down ensures that the predicted life cycle costs are achieved. Performance monitoring of the entire train is a must for plants operating on life cycle cost strategies.
Performance monitoring also plays a major role in extendinglife， diag-nosing problems， and increasing time between overhauls. .n-line performance monitoring requires an in-depth understanding of the equipment being measured. Most trains are very complex in nature and thus require very careful planning in installation of these types of systems. The developmentof algorithms for a complex train needs careful planning， understanding ofthe machinery and process characteristics. In mostcases， help from the manu-facturer of the machinery would be a great asset. For new equipment， this requirement can be part of the bid requirements. For plants with alreadyinstalled equipment， a plant audit to determine the plant machinery status is the first step.
　
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