Operating a power plant with pyrolysis oil based fuel

A method for switching between pyrolysis oil based fuel operation and crude oil based fuel operation of a pyrolysis oil based fuel internal combustion engine with a fuel recirculating cycle comprising a fuel recirculating unit and an engine fuel system, the method comprising:

• operating the internal combustion engine with a crude oil based fuel such that the fuel recirculating cycle is substantially filled with the crude oil based fuel;
• during continuous operation of the internal combustion engine, switching to operating the internal combustion engine with a cleaning fuel, which is chemically compatible with the crude oil based fuel as well as a pyrolysis oil based fuel and allows operation of the internal combustion engine, by supplying the cleaning fuel to the fuel recirculation cycle, thereby increasing the ratio of the cleaning fuel in the engine fuel system;
• and
• during continuous operation of the internal combustion engine, switching to operating the internal combustion engine with the pyrolysis oil based fuel by supplying the pyrolysis oil based fuel to the fuel recirculation cycle, thereby increasing the ratio of pyrolysis oil based fuel in the engine fuel system.

A pyrolysis oil based fuel power plant comprising:

• a tank system comprising a pyrolysis oil based fuel tank, a cleaning fuel tank system with an ethanol tank and a castor oil tank, and at least one crude oil based fuel tank;
• a fuel treatment system comprising a pyrolysis oil based fuel treatment unit fluidly connected to the pyrolysis oil based fuel tank and configured to treat the pyrolysis oil based fuel, a cleaning fuel treatment unit fluidly connected to the cleaning fuel tank system and configured to generate the cleaning fuel by mixing ethanol and a castor oil, and a crude oil based fuel treatment unit fluidly connected to the crude oil based fuel tank and configured to treat the crude oil based fuel, wherein the cleaning fuel tank system is fluidly connected the pyrolysis oil based fuel treatment unit to provide ethanol or an ethanol-castor oil mixture for cleaning the pyrolysis oil based fuel treatment unit from pyrolysis;
• a fuel conditioning unit comprising a pyrolysis oil based conditioning section, which is fluidly connected to the pyrolysis oil based fuel treatment unit and the cleaning fuel tank system and which is configured to condition a viscosity of the pyrolysis oil based fuel by adding ethanol or an ethanol castor oil mixture to the pyrolysis oil based fuel, and a crude oil based conditioning section, which is fluidly connected to the crude oil based fuel treatment unit;
• an internal combustion engine for operation with the pyrolysis oil based fuel, the cleaning fuel, and the crude oil based fuel, the internal combustion engine comprising an engine fuel system;
• and
• a fuel recirculating unit configured to receive as a fuel the pyrolysis oil based fuel, the cleaning fuel, the crude oil based fuel, and a mixture thereof from the fuel conditioning unit and to supply the engine fuel system with the same, the fuel recirculating unit comprising a circulation tank, which is fluidly connected to each of the pyrolysis oil based conditioning section, the cleaning fuel treatment unit, the crude oil based conditioning section, and the engine fuel system.