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Heat recovery from a TMP plant is available at a number of different levels depending upon a given mill's process and heat utilization requirements.
In all applications, fiber carry over with the vapor is a concern and venturi scrubbers are frequently used to remove this fiber.
Many primary TMP refiners operate at elevated pressures and blow their pulp at these pressures generating contaminated steam. This steam can be
recovered as clean steam at a slightly reduced pressure using a falling film reboiler. Boiler feed water is circulated on the shell side, falling
down the outside of the tube wall, condensing the foul vapor within the tubes and generating clean steam.
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Because TMP vapors contains NCG, a portion of the vapor must be vented from the reboiler to a secondary condenser. The secondary condenser
is used to preheat the boiler feed water going to the shell side of the reboiler. Other refiner processes operating under pressure may also
be recovered as clean steam.
Many times the secondary, tertiary and rejects refiners are atmospheric operation and generate contaminated steam containing a substantial amount
of air. This heat may be recovered as either hot process water using shell and tube condensers or as hot process condensate using a barometric
condenser.
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