IECM 12.0 beta User Manual > Modules Included with the IECM > Pulverized Coal (PC) Plant > SET PARAMETERS > Base Plant >

Base Plant Performance

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Inputs for the major flow rates and concentrations of the gas and solids streams are entered on the Base Plant Performance parameter screen. The first seven parameters are highlighted in blue. The following parameters are provided:

•Gross Electrical Output: This is the gross output of the generator in megawatts (MWg). The value does not include auxiliary power requirements. The model uses this information to calculate key mass flow rates.

•Unit Type: This is the type of steam turbine system being used. The possible selections are: Sub-Critical, Super-Critical, and Ultra- Supercritical. This selection determines the steam cycle heat rate default value.

•Steam Cycle Heat Rate: This is the gross amount of energy in steam needed to produce a kilowatt-hour (kWh) of electricity at the generator. This variable does not consider auxiliary power requirements. This heat rate, plus the boiler efficiency, is used to figure out the overall plant performance (i.e., the gross cycle heat rate).

•Boiler Firing Type: Combination boilers are most often represented by three types: Wall, Tangential, and Cyclone. The Wall category is the most general and represents variations such as opposed, top, cell, and others. The selection of boiler type affects the boiler efficiency and furnace emission factors.

•Boiler Efficiency: This is the percentage of fuel input energy transferred to steam in the boiler. The model default is to calculate the boiler efficiency using standard algorithms described in the literature. The efficiency is a function of energy losses due to inefficient heat transfer across the preheater, latent heat of evaporation, incomplete combustion, radiation losses, and unaccounted losses.

•Excess Air for Furnace: This is the excess theoretical air used for combustion. It is added to the stoichiometric air requirement calculated by the model. The value is calculated and based on the fuel type and boiler type.

•Leakage Air at Preheater: This is the additional excess air introduced because of leakage into the system at or beyond the air preheater. It is based on the stoichiometric air required for combustion. The leakage air increases the total gas volume downstream of the air preheater.

•Gas Temperature Exiting Economizer: This is the temperature of the flue gas exiting the economizer. The temperature is used in the calculation of the flue gas volume and air preheater performance.

•Gas Temperature Exiting Air Preheater: This is the temperature of the flue gas exiting the air preheater. The temperature is used in the calculation of the flue gas volume and air preheater performance.

•Percent Water in Bottom Ash Sluice: Bottom ash collected can be removed from the combustion boiler and disposed by sluicing the bottom ash with water. This is the percent water in the sluice.

•Hydrated Lime for SO3 Removal: Hydrated lime is injected for flue gas treatment at the inlet of the air preheater to remove SO3.

•Base Plant Power Requirements: These parameters specify the electrical power requirements of pulverizers, steam pumps, forced draft fans, cooling system equipment (fans and pumps), and other miscellaneous equipment excluding gas cleanup systems. These power requirements or penalties are expressed as a percent of a gross plant capacity and are used to calculate the net plant performance.

•Coal Pulverizer: This is the power needed to run the coal pulverizers prior to the coal being blown into the boiler. It is also referred to as an energy penalty to the base plant. The value is calculated and based on the fuel type. It is expressed as a percentage of the gross plant capacity.

•Steam Cycle Pumps: This is the power needed to operate the pumps in the steam cycle. It is also referred to as an energy penalty to the base plant. It is expressed as a percentage of the gross plant capacity.

•Forced/Induced Draft Fans: This is the power required for the forced draft fans and primary air fan expressed as a percentage of the gross plant capacity. It is also referred to as an energy penalty for the base plant.
Once-Through Cooling System: (Only visible when once-through cooling is selected) This is the power needed to run the pumps and other equipment for the once-through cooling system. It is expressed as a percentage of the gross plant capacity. It is also referred to as a base plant energy penalty.

•Miscellaneous: This is the power used by any other miscellaneous equipment in the base plant, not including equipment used for pollution control equipment. It is expressed as a percentage of the gross plant capacity. It is also referred to as a base plant energy penalty.