ConocoPhillips has stated that its Immingham combined heat and power plant in northeast England, on the same site as its Humber oil refinery, was ‘progressing the commissioning and start-up work of its 450 MWe Phase II expansion’ to an expected date in Q4 but gave no exact date or month. This is a few months later than the originally projected start date of summer 2009.
The plant, which commenced commercial operation in late 2004 and is one of the largest, cleanest and most efficient of its type in Europe supplies steam and electrical power to the Humber oil refinery and steam to the Total Lindsey oil refinery, two of the largest in the UK, on the adjacent site in North Lincolnshire.
In October 2006 ConocoPhillips announced approval of an investment of approximately $400m (£320m) to expand capacity at the ICHP from 730 MW to 1180 MW. Then in January 2008 the plant was put up for sale at a price of £500 million, a move that Conoco described as routine asset assessment, but it was at pains to assure prospective buyers that the extension plan would not be affected. Nor was it.
This capacity addition will make Immingham CHP one of the world’s largest and most efficient power stations, although a study to determine the economic feasibility of modifying the enlarged plant to utilise gasification technology, enabling it to operate as a ‘clean coal’ facility, was deferred when the UK government decided last year to exclude gasification from its clean carbon competition.
Main components
The original 734 MWe plant (see schematic below) has four boilers (two HRSGs and two auxiliary boilers) sharing a single four-flue chimney. The plant is designed to operate in several different modes, exporting anything from 150 MWe to 734 MWe to the grid, while maintaining steam supply to the two refineries. It is equipped with two 260 MWe GE 9FA gas turbine generating sets, each exhausting into a Nooter Eriksen HRSG. Both of the HRSGs have extensive supplementary firing, and in addition there are the two auxiliary boilers. The plant has two Franco Tosi supplied steam turbines, which also generate electricity (115 MWe each), and from which steam is extracted at 50 bar for refinery use. The power plant internal house load is around 20 MWe.
The extension, for which the main contractor is Black & Veatch, is centred on a single GE 285 MW 9FB gas turbine exhausting into an HRSG which supplies steam at 100 bar to the common header. After being expanded through a 200 MW Toshiba steam turbine steam is fed to the 50 bar common header supplying the refineries. Several links between the 50 bar and 100 bar headers ensure continuity of steam supply. Electricity production will remain heat demand led.
