© MANTRA Innovative Systems 2013

Tomorrow's Energy Solutions.
PULP & PAPER PRODUCTION FACILITY INVESTS IN PROCESS STEAM EXCHANGER & WATER PRE-HEATER
As a major producer of specially designed plywood products including veneer, densified wood, and beech bedslats, this pulp and paper facility consumes over 28,000 cubic meters of logs each year.
Because the veneer production process is heavily reliant on steam processing, the cost of energy remains one of the major production costs in this industry. Efficient energy use is imperative for this facility, leading to the 2005 implementation of the company’s Environment Management System, through which the company became a leader in the integration of innovative fuel efficiency and carbon reducing technology in the pulp and paper industry.




SELECTION CRITERIA
CHALLENGES
The main goal for this organization was to recover and reuse the wasted energy in the exhausted air, reducing the immense energy demand for the production process. From a maintenance aspect, use of classic heat exchanger design would not be possible due to the high particulate environment resulting from the wood-fired diathermic oil heating system used to carry heat to remote points throughout this very large facility.


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TECHNICAL DATA
Exhaust temp in: 752° F
Exhaust temp put: 248° F
Steam Rate: 2,204 lb/hr
Steam Pressure: 21.75 psi
Energy recovered: 978 kW
SOLUTION
In order to reduce their steam costs MANTRA proposed an exhaust gas-to-steam exchanger with an in-series feed water pre-heater. The unit was installed on the exhaust flow from the plant’s wood-fired diathermic oil heating station.
Being wood-fired, the exhaust flow was naturally very high in particulate which prevented the use of a classic heat exchanger design. Utilizing removable panels on the gas side of the heat pipes, the unit provided the perfect solution to deal with the difficult exhaust stream. To further reduce the amount of particulate entering the exchanger, a dynamic trap was designed into the unit to remove as much particulate as possible.
RESULTS
The dual output of hot water and steam from the installed unit provided flexibility so that constant energy recovery levels could be maintained against a variable production requirement of steam and water. The completed heat pipe heat exchanger unit has proved effective over many years of reliable service, maintaining constant performance and high reliability with associated low maintenance.