2. Compressor
3. Combustor
4. Expander turbine
Air Inlet Filter Module
Loss computation， this enables the operator to ensure that the filters are clean and that no additional losses than necessary reduce the performance of the gas turbine. The following parameters are necessary to monitor the filter:
1. Time to replace each stage of filters
2. Filter plugged index to monitor the condition of each stages of filters
3. Inlet duct air leak
.ompressor Module
The compressor of a gas turbine is one of the most important components of the gas turbine. It consumes between 0-6 % of the energy produced in a gas turbine. Thus fouling of the compressor can cause large losses in power andefficiency for the gas turbine. Furthermore， the fouling of the compressor alsocreates surge problems， which not only affects the performance of the com-pressor but also creates bearing problems and flame-outs. The following are some of the major characteristics that need to be calculated:
Over ll p r meters oj the Compressor.
1. Efficiency
2. Surge map
3. Compressor power consumption
4. Compressor fouling index
.04 Gas Turbine Engineering Handbook
. Compressor deterioration index
6. Humidity effects on the fouling
7. Stage deterioration
Compressor Losses. These losses are divided into two sections:
1. Controll ble Losses.Losses， which can be controlled by the action of the operator such as:
a. Compressor fouling
b. Inlet pressure drop
2. Uncontroll ble Losses.Losses， which cannot be controlled by the operator such as:
a. Ambient pressure
b. Ambient temperature，this， in cases of refrigeratedinlets， could be controlled but in most applications is uncontrolled.
c. Ambient humidity
d. Ageing
Compressor Wash.When should the compressor be washed on-line， and when should an off-line compressor wash should be considered.
On-line Wash. This wash is done by many plants as the pressure drop decreases by more than 2%. Some plants do it on a daily basis. The water for these washes must be treated.
Off-line Wash. Figure 20-7 shows that on-line water wash will not returnthe power to normal thus after a number of these washes， an off-line water wash must be planned. This is a very expensive maintenance program and must be fully evaluated before it is undertaken. Chapter 12 deals with the various washes in detail.
.ombustor Module
The calculation of the firing temperature is one of the most important calculations in the combined cycle performance computation. The temper-ature is computed using two techniques (1) Fuel Heat Rate (2) Power Balance. The following are the important parameters that need to be computed:
1. Combustor efficiency
2. Deterioration of combustor
3. Turbine inlet temperature (first stage nozzle inlet temperature)
4. Flash back monitor (for dry low NOx combustors)
. Specific fuel consumption
TIME
Figure 20-.. Com.ressor water wash characteristics.
..pander Module
The calculation of the turbine expander module depends whether or not this is a single shaft gas turbine or a multiple shaft gas turbine. In aero-derivative turbines， there are usually two or more shafts. In the latestaero-derivative turbines， there are usually two compressor sections， the LPcompressorsection， and the HP compressor section. This means that the turbine has three shafts; the third shaft is the power shaft. The turbines thatdrive the compressor section are known as the gasifier turbines， and theturbine， which drives the generator， is the power turbine. The gasifier turbine produces the work to drive the compressor.
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