The prime mover is a Mitsui MAN B&W 12K80MC-GI-S with power of 40,680 kW at the crankshaft end. Main fuel is LNG (city gas) and pilot fuel is low sulfur diesel oil, with an over all calorific mixing ratio of 90 to 10, though at 100% load the mixing ratio is 92 to 8.
The gas compressor is a Mitsui-Thomassen 4-stage reciprocating type compressor. Suction pressure is 4.5 bar from a gas pipeline utility and delivery pressure to the engine is 300 bar.
NOx emissions are controlled by a Selective Catalytic Reactor (SCR) to meet the strict Tokyo Bay environmental rules, requiring an NOx limit of 75 ppm at 15% O2 (100 ppm at 13% O2). The ammonia for the reactor is supplied directly from an adjacent producer to which steam is fed from Chiba GIDE. A duct burner is placed before the SCR tower to heat up the SCR during engine low load. The installation diagram for the SCR is shown in Fig.2.
The plant operation mode is daily start and stop operation according to the demand of Tokyo Electric Power Company. Annual running hours are around 2,000 hours. Total generating power, running hours, reliability and efficiency are listed in Table 2 from the beginning of the operation of the plant and up to the end of March, 2000.
Average plant reliability is 97.0% and over all plant efficiency at generator end is 44.9% while plant efficiency at supply end is 41.5%. The above mentioned average plant reliability of 97.0% is almost equal to other modern MAN B&W two-stroke low speed diesel power plant using normal liquid fuel (97-99%) in spite of the fact that the Chiba GIDE is a pilot plant of GI-technology.
Number of all troubles, by which the plant operation had to be stopped against the demand from TEPCO, is 62 times from the start of operation to the end of March 2000 as shown below:
Trouble of auxiliary equipment is very small and the gas compressor is very reliable. The status of the gas compressor is described later. There was almost no trouble of outside fitted plant equipment except for cooling sea water line where the sea water filter was clogged by sea weed time to time. Troubles listed under 'Others' were computer trouble, sensor failure and others.
3. Experience of main engine and gas compressor
Detail experience of engine and gas compressor are described in the following, based on the 14,000 running hours reached at the end of March 2000.
Owing to well proven MC principle, trouble related to the basic MC design has been very few. No big trouble was experienced except for one turbocharger bursting in July 1995. This was a compressor wheel bursting that was experienced also in other stationary plant and marine application as well around that time. After a design change of the turbocharger, no further trouble has been informed.
