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Thermo-Mechanical Pulping(TMP) Industry
Heat Recovery Systems
Heat recovery from a TMP plant is available at a number of different levels, depending upon the mill’s process and heat utilization requirements. AHL brings decades of experience in designing and deploying these systems to eturn maximum benefit.
TMP Refiner Heat Recovery (Atmospheric)
In many plants refiners are operated at low or near atmospheric discharge pressures and generate contaminated steam, often vented to atmosphere. This heat may be recovered as either hot process water using shell and tube condensers or as hot process condensate using direct contact condensers.
AHL provides both direct and indirect heat recovery systems, designed to resist fibre fouling and provide high efficiency heat recovery from the vent steam. Additionally, the systems are applicable to steam vented from stock chests containing large amounts of air.
TMP Refiner Heat Recovery (Pressurized)
Thermal Mechanical Pulp (TMP) refiners may be operated 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. The contaminated steam is directed to condensing service on the tube side of the reboiler.
Boiler feed water is circulated on the shell side, falling down the outside of the tubes and generating clean steam. Heat recovery generally exceeds 96% thermal efficiency. Clean steam generation is designed to achieve discharge pressures within 5-7 psi of the contaminated steam inlet pressure to the reboiler.
The AHL design incorporates a venturi scrubber and wet cyclone into the reboiler, minimizing the impact of fiber carry-over and reducing fouling to a minimum. As a result, our TMP heat recovery systems have operated continuously in excess of many years without the requirement of shutting down for off-line cleaning.