RELAY 4329162 - Caterpillar

Engines Modified to Operate Using Heavy Fuels
The operation of Caterpillar 3600 Family of engines with heavy fuels requires attention to maintenance intervals and inspections. Trained operations personnel are also required for the special processing and handling of the fuel being used. In addition, special modifications and/or derating of the engine may be required.Heavy fuels require special handling. This involves heating of the fuel to obtain proper viscosity, possibly blending, centrifuging, filtering, as well as engine modifications and extra engine maintenance. In addition, special training is required for personnel (crew) to process and handle the fuel to be used.Heavy crude and blends have less specific heating value than light crude, light blends, and distillate fuels. Crude and blended fuels also contain sulfur, free water (H2O), and sediment which does not contribute to heating value.With heavier fuel, more mass will be required because of lower specific energy. Therefore, it will take more heavy fuel to achieve the same power generation than if an MDO diesel fuel was used.Engine life will be reduced by using heavy fuels. Heavy fuels may contain larger amounts of sulfur and vanadium. The presence of these elements will cause highly corrosive compounds, which increases wear of rings, liners, valves and valve guides.Fuel sulfur can be dealt with by using the proper lubrication oils with sufficient TBN to neutralize the effect of the sulfur.Vanadium cannot currently be economically removed from heavy (residual) fuels. Engine modifications such as increased valve cooling, special valves, high overlap cam, engine derating and water cooled valve inserts are required to reduce the effect of vanadium. Fuel additives, typically magnesium compounds may not be economical to use in treating vanadium fuels.It may be necessary to blend more distillate fuels with the heavy (residual) blend to reduce contaminant levels. This will require a highly trained crew to filter, heat and blend the fuel as well as perform the necessary fuel tests.Heavy fuel characteristic limits for the 3600 engine family and recommended test description for each of the contaminants. Additional Heavy Fuel Requirements
Fuel Tests
1. Test and analyze bunkered fuel on a regular basis to track contaminant levels.2. Before bunkering fuel, test compatibility of bunkered fuel with fuel being purchased. Use separate tanks if possible for bunker fuels.3. Analyze lube oil (using Scheduled Oil Sampling or an alternate laboratory) on a regular basis for wear metals, differential infrared analysis, kinematic viscosity (ASTM D664) and TBN level (ASTM D2896).Engine Operation
Excessive operation at low engine load can be detrimental to engine component life. Refer to the chart below for the approximate time at low load while utilizing heavy fuels. If operation at low load is expected beyond these times, the engine should be operated utilizing No. 2 or marine diesel fuel. Switch over must be accomplished so unit injectors are not starved of fuel. It is preferable to change fuels via a mixing tank, so cold No. 2 fuel is not put into a hot system, causing gaseous mixture in fuel line. The mixing tank should be capable