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Alternative cleaning strategies for membranes in biorefineries

Rudolph, Gregor LU orcid ; Jönsson, Ann-Sofi LU and Lipnizki, Frank LU orcid (2018) Euromembrane 2018
Abstract
The pulp and paper industry is one of the most important industrial sectors worldwide. The focus of current pulp mills is on the production of cellulose pulp fibres and electricity. By converting traditional pulp mills into biorefineries they can be a keystone in a future bioeconomy based on renewable resources instead of fossil fuels. In order to achieve this, pulp mills have to close their loops and focus on the optimal utilisation of the lignocellulosic raw material not only for fibres but also for the production of biochemicals, biofuels and other advanced materials.
Thermomechanical pulping (TMP) is one of most widely used pulping processes. However, its current concept results in large quantities of process water containing very... (More)
The pulp and paper industry is one of the most important industrial sectors worldwide. The focus of current pulp mills is on the production of cellulose pulp fibres and electricity. By converting traditional pulp mills into biorefineries they can be a keystone in a future bioeconomy based on renewable resources instead of fossil fuels. In order to achieve this, pulp mills have to close their loops and focus on the optimal utilisation of the lignocellulosic raw material not only for fibres but also for the production of biochemicals, biofuels and other advanced materials.
Thermomechanical pulping (TMP) is one of most widely used pulping processes. However, its current concept results in large quantities of process water containing very diluted lignocellulosic components such as cellulose, lignin, hemicellulose and extractives and are today send for biological wastewater treatment. An efficient separation and concentration of these wood chemicals could be fundamental in utilising the TMP process in future pulp mill biorefineries. The pressure-driven membrane processes microfiltration (MF) and ultrafiltration (UF) have been identified as high potential processes for the separation and concentration of lignocellulosic components. During the separation process, MF and UF are experiencing membrane fouling resulting in flux reduction and changes in membrane retention, which have both a negative impact on the process economy. However, flux and retention can be recovered by regular cleaning but improved cleaning protocols and new cleaning agents are required to obtain a sustainable process.
Therefore, this study focus on the cleaning of polymeric membranes used for the separation of hemicellulose from TMP process water which are severely fouled due to the presence of polysaccharides and proteins. Typical conventional cleaning protocols for such fouling include generally the use of strong alkaline solutions with added detergents at high temperatures resulting in a reduced membrane life cycles, Anton et al. (2015). Alternatively, enzymatic membrane cleaning protocols could be adopted which are more sustainable since they have a lower environmental impact and require less harsh conditions with regard to temperature and pH. Thus, the aim of this work is to compare different conventional and enzymatic cleaning protocols with regard to flux and retention recovery of the membranes fouled by TMP process water.
This work will show that on the one hand polysaccharide degrading enzymes can help to enhance the cleaning of membranes fouled with TMP process water and thus resulting in a longer membrane life cycle and less environmental impact, but on the other hand it will also reveal that there is still further development of cleaning agents and protocols required to obtain a complete environmental friendly replacement for current cleaning agents and protocols. Overall, this study will highlight that effective and sustainable membrane cleaning is a key for the true transformation of pulp mills into biorefineries. (Less)
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author
; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Membrane filtration, cleaning
host publication
Euromembrane 2018
conference name
Euromembrane 2018
conference location
Valencia, Spain
conference dates
2018-07-09 - 2018-07-13
language
English
LU publication?
yes
id
7792e46d-7d0e-4b79-b07f-297c942352eb
date added to LUP
2018-09-27 11:16:31
date last changed
2019-03-08 02:29:46
@inproceedings{7792e46d-7d0e-4b79-b07f-297c942352eb,
  abstract     = {The pulp and paper industry is one of the most important industrial sectors worldwide. The focus of current pulp mills is on the production of cellulose pulp fibres and electricity. By converting traditional pulp mills into biorefineries they can be a keystone in a future bioeconomy based on renewable resources instead of fossil fuels. In order to achieve this, pulp mills have to close their loops and focus on the optimal utilisation of the lignocellulosic raw material not only for fibres but also for the production of biochemicals, biofuels and other advanced materials.<br/>Thermomechanical pulping (TMP) is one of most widely used pulping processes. However, its current concept results in large quantities of process water containing very diluted lignocellulosic components such as cellulose, lignin, hemicellulose and extractives and are today send for biological wastewater treatment. An efficient separation and concentration of these wood chemicals could be fundamental in utilising the TMP process in future pulp mill biorefineries. The pressure-driven membrane processes microfiltration (MF) and ultrafiltration (UF) have been identified as high potential processes for the separation and concentration of lignocellulosic components. During the separation process, MF and UF are experiencing membrane fouling resulting in flux reduction and changes in membrane retention, which have both a negative impact on the process economy. However, flux and retention can be recovered by regular cleaning but improved cleaning protocols and new cleaning agents are required to obtain a sustainable process.<br/>Therefore, this study focus on the cleaning of polymeric membranes used for the separation of hemicellulose from TMP process water which are severely fouled due to the presence of polysaccharides and proteins. Typical conventional cleaning protocols for such fouling include generally the use of strong alkaline solutions with added detergents at high temperatures resulting in a reduced membrane life cycles, Anton et al. (2015). Alternatively, enzymatic membrane cleaning protocols could be adopted which are more sustainable since they have a lower environmental impact and require less harsh conditions with regard to temperature and pH. Thus, the aim of this work is to compare different conventional and enzymatic cleaning protocols with regard to flux and retention recovery of the membranes fouled by TMP process water.<br/>This work will show that on the one hand polysaccharide degrading enzymes can help to enhance the cleaning of membranes fouled with TMP process water and thus resulting in a longer membrane life cycle and less environmental impact, but on the other hand it will also reveal that there is still further development of cleaning agents and protocols required to obtain a complete environmental friendly replacement for current cleaning agents and protocols. Overall, this study will highlight that effective and sustainable membrane cleaning is a key for the true transformation of pulp mills into biorefineries.},
  author       = {Rudolph, Gregor and Jönsson, Ann-Sofi and Lipnizki, Frank},
  booktitle    = {Euromembrane 2018},
  language     = {eng},
  title        = {Alternative cleaning strategies for membranes in biorefineries},
  year         = {2018},
}