Technology Marketing Incorporated

Techmark Corporation

James L Wise

David Dyer

Method and apparatus for recovery of waste heat from thermomechanical pulping systems and the like in which waste heat in the form of steam exhausted from the mechanical pulper and latency chest portions of the thermomechanical pulping system are respectively passed through first and second evaporators which increase the enthalpy of the working liquid. The working fluid outputted from the first evaporator passes through a first compressor to significantly increase both pressure and temperature and further increase enthalpy. The working fluid at the outlet of the first compressor then undergoes desuperheating within an intercooling tank. The liquid phase of the working fluid is passed from said tank to the inputs of both evaporators, while the vapor phase merges with the working fluid outputted from the second evaporator and enters a second compressor to undergo further increases in pressure and temperature. The working fluid emerges from the second compressor and is passed through a condenser where it transfers its heat energy to water passing through the condenser, which water is converted to steam at a pressure well in excess of atmospheric. The working liquid, in giving up its heat energy, is converted into the liquid phase and is passed to the intercooling tank which serves as a means to balance differences in the mass flow rate, temperature, pressure and enthalpy of the working fluids respectively passing through the first and second compressors, thereby allowing the first and second compressors to operate at different temperature and pressure levels although they are driven by a common prime mover. The waste heat recovery system produces extremely useful high pressure, high temperature steam, free of the impurities present in the steam vented by the thermal mechanical pulping system. One of the above-mentioned evaporators may be omitted in applications where waste energy is derived from a single source. The system may be used in conjunction with other systems developing high waste energy such as dryer systems. Other techniques are employed to further enhance the coefficient of performance of the system.

Method and apparatus for recovering waste energy

Method and apparatus for recovery of waste heat from thermomechanical pulping systems and the like in which waste heat in the form of steam exhausted from the mechanical pulper and latency chest portions of the thermomechanical pulping system are respectively passed through first and second evaporators which increase the enthalpy of the working liquid. The working fluid outputted from the first evaporator passes through a first compressor to significantly increase both pressure and temperature and further increase enthalpy. The working fluid at the outlet of the first compressor then undergoes desuperheating within an intercooling tank. The liquid phase of the working fluid is passed from said tank to the inputs of both evaporators, while the vapor phase merges with the working fluid outputted from the second evaporator and enters a second compressor to undergo further increases in pressure and temperature. The working fluid emerges from the second compressor and is passed through a condenser where it transfers its heat energy to water passing through the condenser, which water is converted to steam at a pressure well in excess of atmospheric. The working liquid, in giving up its heat energy, is converted into the liquid phase and is passed to the intercooling tank which serves as a means to balance differences in the mass flow rate, temperature, pressure and enthalpy of the working fluids respectively passing through the first and second compressors, thereby allowing the first and second compressors to operate at different temperature and pressure levels although they are driven by a common prime mover. The waste heat recovery system produces extremely useful high pressure, high temperature steam, free of the impurities present in the steam vented by the thermal mechanical pulping system.

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Depere, WI, United States of America

James L Wise