Heat Recovery Systems Vol. 5, No. 1, pp. 71-79, 1985. 0198-7593/85 $3.00 + 0.00 Printed in Great Britain. Pergamon Press Ltd

E N E R G Y

C A S E H I S T O R I E S

C O N S E R V A T I O N D E M O N S T R A T I O N

P R O J E C T S S C H E M E

The UK Energy Efficiency Office is now issuing 'Extended Project Profiles' describing in some detail a number of completed demonstration projects which received support under the Energy Conservation Demonstration Projects Scheme (ECDPS). Data from four of these Extended Project Profiles are given below, covering two studies involving recuperative burners, a combined heat pump and run-around coil installation and a combined heat and power demonstration based on the use of a gas turbine.

Further information, including copies of detailed project final reports, may be obtained from the Enquiries Bureau, Energy Technology Support Unit, Building 156, AERE Harwell, Didcot, Oxfordshire, OXI 1 0RA, UK, (Tel. 0235 834621, Telex 83135).

G A S T U R B I N E E X H A U S T U S E D A S B U R N E R

C O M B U S T I O N A I R

A Demonstration of Combined Heat and Power Generation Reducing the Fuel Consumption of Fired Heaters in an Oil Refinery. Also of Special Interest to Chemical Plants and Steelworks.

T H E A I M O F T H E P R O J E C T

Fired heaters are used extensively in refineries for process heating in pipe stills on crude and vacuum distillation units and in reboiler/feed heaters. This demonstration shows that a number of fired heaters can be supplied with preheated combustion air from the exhaust of a gas turbine and so save fuel. At Conoco's Humber Refinery, a 10MW gas turbine was installed to supplement the electricity generated at the plant. The exhaust from the turbine was fed to three gas-fired heaters used in the hydrodesulphurisation of distillate. It was anticipated that the combination of these measures would result in a reduction in annual energy consumption of 888,000 million Btu (936,000 GJ or 23,000 tonnes heavy fuel oil). Energy savings of this order were achieved in the demonstration.

I M P L E M E N T A T I O N O F E N E R G Y S A V I N G M E A S U R E S

An oil refinery uses most of its energy in directly firing its heaters and generating its electricity. Conoco was looking for ways to reduce fuel consumption of its fired heaters and also needed to replace its ageing steam turbine generating system. To fulfill both aims, the company installed a 10 MW gas turbine from which the hot exhaust was fed to the burners of three large process heaters serving the hydrodesulphurisation unit. The installation became operational in March 1982 and has reduced energy consumption since. The changes were made as part of the Department of Energy's Energy Conservation Demonstration Projects Scheme to encourage take-up of similar measures in other refineries, in chemical plants and in steelworks.

Originally power was supplied to the refinery by three 5 MW and two 3 MW generators driven by steam condensing turbines and fuelled by a combination of refinery off-gases and heavy fuel oil. The heaters, of vertical cylindrical design were fired from the bottom with similar off-gases using natural draught burners operating with ambient air.

Major modifications included installing a gas-turbine driven generator rated at 10 MW, changing the heater burners and installing ducting to carry the hot turbine exhaust. A two-shaft turbine was selected which had an exhaust rate that more than matched the combustion air requirements of

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