Garri Gas Turbines Fuel System Modification

Abstract

Garri 1 combined cycle power plant is one of the important power plants in the national grid consisting of 4 (four) gas turbine units, 4 (four) HRSG and 2 (two) steam turbine. The main problem of Garri 1 combined cycle power plant is expensive light diesel fuel oil (LDO), The price of the used fuel oil in Garri 1 is about 1,739.5 SDG/ton, if we considered that each gas turbine unit consumes about 9 ton/hour at base load, we can estimate the cost of fuel for all units is 62,622.00 SDG/hour. However these gas turbine units have the option of dual fuel (LDO) light diesel oil and (LPG) liquefied petroleum gas, but due to the lack of production of LPG they are run by LDO mainly, which increases the operational cost of the plant, and accordingly affects the cost of produced kW.h from the plant. Looking for the solution to this problem is being an important aim of the top management of STPG. Therefore this study concentrated on the available opportunity to transform the fuel type of the plant by using perspective and more low-cost fuel such as: • Natural Gas (NG). • Sponge Coke (Gasification). • Liquefied Petroleum Gas (LPG). • Heavy Coked Gas Oil (HCGO The last option of fuel (HCGO) is more recommended due to the following reasons:  No availability of the (NG) nearby the plant location, however, this option could be possible if the NG exploration has been succeeding in any part of the country or importing facilities has been constructed.  The production of the sponge coke now from Khartoum Refinery Company (KRC) is enough just to run Garri plant 4 (2x55 MW).  (HCGO) is now used in Dr. Mahmoud Shareef Power Station {Phase I (2 x 30 MW) and Phase II (2 x 60 MW)}, but the efficiency of the units vary between 27 to 30 %, while in Garri 1 combined cycle the efficiency is higher than (47 %).  Transportation of (HCGO) from KRC to the power station is expensive if compared with transported from KRC to Garri power station, which lays beside KRC and fuel oil delivered by a pipeline.