Open this publication in new window or tab >>2009 (English)In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, p. 190-194Conference paper, Published paper (Refereed)
Abstract [en]
In a mechanical pulping process, (TMP) wood is refined to pulp in a process with very high wood utilization. However, the power demand in the process is high. Thus efficient energy recovery, especially steam recov-ery, is very important. In high consistency (HC) refining the pulp wood is refined at high temperature (140°C) and pressure. The high temperature makes it possible to recover process heat with usable steam properties.
One strategy to decrease the power consumption is to split the refining into two stages, one HC-stage and one low consistency (LC) refining stage. This kind of sys-tem is quite common today. One drawback with LC-refining is that it operates at a low temperature normally below 100°C. Hence, the steam recovery potential from conventional LC-refining is limited.
In this project, we analyse three concepts of steam re-covery in LC-refining by increasing the temperature in the LC-stage. Two base cases: Conventional HC refin-ing only and conventional HC/LC refining is compared with three steam recovery cases: Pulp/Pulp heat ex-changing, Screw Press Dewatering combined with proc-ess water re-circulation and finally Pulp/Water Heat Exchanging.
The study shows that it is possible to recover steam from the LC-stage and, hence, increase the energy effi-ciency of a combined HC/LC refining system. The screw press case has the highest steam recovery poten-tial of the HC/LC configurations. An initial economic estimate indicates that steam recovery in LC-refining is profitable compared to a conventional HC/LC-configuration.
Keywords
energy efficiency, steam recovery, mechanical pulping.
Identifiers
urn:nbn:se:miun:diva-10192 (URN)2-s2.0-77951099503 (Scopus ID)
Conference
2009 International Mechanical Pulping Conference, IMPC 2009; Sundsvall; 31 May 2009 through 4 June 2009; Code 79937
2009-10-292009-10-272011-04-06Bibliographically approved