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Thermodynamic analysis of the support steam system at Karlshamnsverket.

Tim Jonsson
Göteborg : Chalmers tekniska högskola, 2012. 32 s. Examensarbete. T - Institutionen för energi och miljö, Avdelningen för energiteknik, Chalmers tekniska högskola, ISSN 9897232, 2012.
[Examensarbete på avancerad nivå]

Karlshamnsverket is an oil fired reserve power plant, situated in the southeast part of Sweden. The power plant consists of three units with a total capacity of 996MWel and it operates at least 4000 hours in standby annually. The most common standby mode is the 2 hour standby. At 2 hour standby mode the power plant is required to produce electricity to the grid within 2 hours. The order for a start-up is either given by the owners or Svenska Kraftnät. During standby the power plant needs steam to maintain readiness. Steam is supplied to the support steam system, either by an electric heater or by an oil boiler. The support steam system is divided into two circuits, a non-oil circuit and an oil circuit. Within these two circuits there are a total of ten heat consumers that are active during 2 hour standby. A heat consumer in this thesis is connected to the support steam system and is supplied with steam during 2 hour standby. Such heat consumer may be the deaerator or the heating of the oil tanks. At this time the amount of steam supplied to the heat consumers during 2 hour standby is unknown. The oil boiler of the support steam system has during a normal year 3000 operating hours. This means fuel is consumed when the power plant is not running, thus not generating any profit, only increased costs, for Karlshamnsverket. Therefore there is a strong economic incentive to reduce the running cost of the support steam system. In this thesis the support steam system and its heat consumers are mapped and measured at 2 hour standby to determine their respective heat requirement. The results from the measurements show that a total of 18.1MW of steam is required to operate the support steam system at maximum load. The oil boiler of the support steam system has a maximum capacity of 13MWsteam. The efficiency of the oil boiler is determined to be 85% via a created model. At this load the oil boiler has approximately 2MW of flue gas losses. This flue gas loss can be minimized, thus increasing the energy efficiency of the oil boiler. The suggested energy efficiency measure is to install an economiser into the present oil boiler’s flue gas train. To avoid flue gas condensation the economiser is placed after the current Electro Static Precipitator (ESP). The proposed capacity of the economiser is 1.4MW and delivers feed water at 80ºC to the oil boiler. This lowers the fuel consumption with approximately 46tons of LS HFO per year. The investment cost is approximated to 1.5MSEK, resulting in a payback period approximately to 4 – 5 years. The annual savings are determined to be between 300 000 – 340 000SEK.

Nyckelord: Heavy Fuel Oil, Reserve Power Plant, Support Steam System,

Publikationen registrerades 2012-09-03. Den ändrades senast 2013-04-04

CPL ID: 162790

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