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34th EMS Summer School : Membranes in Biorefineries
- 2017
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Proceedings (redaktörskap) (refereegranskat)abstract
- The EMS Summer School “Membranes in Biorefineries” is related to Annex XVII of the Industrial Energy Related Technologies and Systems (IETS)Implementing Agreement: “Membrane Filtration for Energy-efficient Separation of Lignocellulosic Biomass Components” co-ordinated by the Department of Chemical Engineering at Lund University, Sweden.The IETS Implementing Agreement is an initiative within IEA (International Energy Agency). The mission of IETS is to foster international co-operation among OECD and non-OECD countries for accelerated research and technology development of industrial energy-related technologies and systems. In doing so, IETS seeks to enhance knowledge of cost-effective new industrial technologies and system layouts that enable increase productivity and better product quality while improving energy efficiency and sustainability.
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| 2. |
- Arkell, Anders, et al.
(författare)
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Increasing flux by back-pulsing in the microfiltration of milk
- 2015
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 41, s. 23-25
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Tidskriftsartikel (refereegranskat)abstract
- Milk with extended shelf-life can be produced by microfiltration (MF) and pasteurisation in a cascade arrangement. In a previous study, we have shown that back-pulsing can be used to reduce the energy requirement in the MF of defatted milk. In this study, the influence of back-pulsing on MF was investigated at higher milk fluxes than in a prior study. The MF experiments were performed in constant-flux mode. The operational time until a certain pressure build-up was used as a measure of the performance. Fluxes between 350 and 500 L m−2 h−1 were investigated, with and without back-pulsing (frequencies ranging from 6 to 0.2 min−1). It was shown that the fouling rate was strongly dependent on the permeate flux; higher flux leading to a higher fouling rate. Improved MF performance was found using back-pulsing at a flux of 350 L m−2 h−1, while at higher fluxes, back-pulsing impaired the performance.
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| 3. |
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| 4. |
- Jönsson, Ann-Sofi, et al.
(författare)
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Costs for membrane cleaning – an economic assessment
- 2016
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Konferensbidrag (refereegranskat)abstract
- Cleaning is an inevitable, and often costly, part of most membrane filtration plants. The economic assessment of cleaning costs is often rather arbitrary when researchers design and estimate costs of a membrane plant in a new application. Severity of fouling, operation conditions, cleaning agents and cleaning frequency all influence the costs for membrane cleaning. In addition to the costs of the cleaning process itself, cleaning also affects membrane lifetime, membrane performance during filtration and process down time. The cleaning procedure and cleaning frequency varies from one application to another and most cleaning studies are therefore trial-and-error investigations. Temperature, time, concentration and type of cleaning agent must be adapted to the conditions in each individual application. Furthermore, in some cases it is necessary to use a sequence of different cleaning agents. The influence of cleaning conditions on costs for membrane cleaning is illustrated in this work.
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| 5. |
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| 6. |
- Lipnizki, Frank, et al.
(författare)
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Changing an industry with membrane technology – Converting pulp mills to bio-refineries
- 2017
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Konferensbidrag (refereegranskat)abstract
- The pulp and paper industry is one of the most important industrial sectors worldwide and has a great potential to be the nucleus for the future bio-economy. Today’ pulp industry is mainly focusing on the production of cellulose fibres and electricity, while its future potential includes the production of bio-chemicals, bio-fuels and advanced materials. In order to fulfil their future role, pulp mills will have to adjust their concepts and convert to ligno-cellulosic bio-refineries. Key to these new concepts is the efficient separation of the wood components: cellulose, hemicellulose, lignin plus extractives as raw material for further processing. In particular, the pressure-driven membrane processes microfiltration, ultrafiltration, nanofiltration and reverse osmosis have been identified as high potential technologies to separate of these wood components. The first applications of membrane technology in the pulp industry can actually be dated back to the 1970ies but while membrane technology experienced significant growth in other sectors, it remained a niche technology in the pulp industry. The first part of the presentation will identify potential positions of membrane technology in the concepts of ligno-cellulosic bio-refineries ranging from the separation of lignin from cooking liquor over the extraction and purification of hemicellulose to the purification of platform chemical derived from fermentation of hemicellulose and/or cellulose. The second part of the presentation will discuss the barriers of membrane technology in the pulp industry. Main focus will be thus on scale-up and integration challenges of membrane processes in the pulp industry and fouling/cleaning issues related to pulp applications - both important factors in enabling membrane technology for the pulping industry. Overall, this presentation will demonstrate that membrane technology can play a major role in the conversion of the current pulping industry into bio-refineries and it will highlight approaches enabling the successful integration of membrane technology into this industry.
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| 7. |
- Lipnizki, Frank, et al.
(författare)
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Fouling and cleaning in the food and bioprocess industry: Key aspects in membrane plant operation
- 2017
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Konferensbidrag (refereegranskat)abstract
- 1. INTRODUCTIONFrom the early days of membrane technology fouling has been identified as the most important parameter for the slow integration of technology in the industry [1]. Since then significant progress has been achieved in the field of fouling and cleaning of membranes which are still both key aspects in membrane plant operation in the food and bioprocess industry with a significant impact on membrane plants capital (CAPEX) and operating expenditures (OPEX) and thus the sustainability of membrane processes. The aim of this presentation is to demonstrate the relationship between fouling, pre-treatment, operating conditions and cleaning and how on this background industrial membrane processes can be optimized from a techno-economical point of view. The first part of the presentation will introduce the challenges of cleaning and fouling in the food and bioprocess industry. The second part will demonstrate different approaches to reduce fouling and improve cleaning, while the final part will focus on an application study utilizing approaches to optimize fouling and cleaning and thus OPEX and CAPEX for industrial application in the starch-based sweetener industry. 2. FOULING AND CLEANING CHALLENGESIn the food and bioprocess industry cleaning is an integrated part of the daily plant operation and due to hygienic considerations one cleaning cycle per day will be often required. In many cases the selection of cleaning cycle length, number of cleaning steps and cleaning frequency is quite arbitrary in particular for new applications. Each cleaning cycle is combined with production downtime of either parts or the complete membrane plant and thus the plant design has to compensate for downtime, e.g. a 4-hour cleaning cycle per day requires 17% additional membrane area. Furthermore, each cleaning cycle consists typically of 3 – 4 chemical/enzymatic cleaning steps plus flushing steps in between and at least carried out once per day. Apart from the downtime aspect, each cleaning cycle is associated with costs for cleaning agents, water, heating and electricity. In addition, cleaning has a negative impact on membrane lifetime. Therefore optimizing plant design and operation together with cleaning cycle length, number of cleaning steps and cleaning frequency can improve both plant OPEX and CAPEX significantly. 3. APPROACHES TO MINIMISE FOULING AND CLEANING The initial step to reduce fouling and thus the need of cleaning is to identify the fouling materials and sources. Based on this often optimizing the pre-treatment can lead to significant reductions in fouling, e.g. in the fruit juice industry membrane fouling can be significantly reduced by enzymatic degradation of starches and pectin before clarification of the juice, while in the fermentation industry sufficient pre-filtration with a self-cleaning strainer can reduce the risk of fouling and module blockage. Apart from understanding of the fouling materials it is important to identify the fouling mechanisms. Depending on the fouling mechanism e.g. complete pore blockage, partial pore blockage or cake filtration remedies to minimize the fouling can be considered. Approaches to minimize fouling are e.g. constant transmembrane pressure operation for milk filtration, vibrating modules for recovery of beer from tank bottoms or rotating modules for white water recovery in the paper industry. Since often fouling cannot be complete avoided despite best efforts or a hygienic requirement, cleaning is an inevitable part of plant operation. It is crucial that temperature, time, concentration and type of cleaning agents are adapted to the individual application and membranes used. One consideration to improve the cleaning process is to move from one comprehensive daily cleaning to two shorter cleanings. Using this approach for e.g. animal blood concentration reduces overall cleaning time and increases the overall plant capacity. 4. APPLICATION STUDY: STARCH-BASED SWEETENER INDUSTRYIn the starch-based sweetener production, the removal of impurities from the sweeteners after liquefaction and saccharification of the starch is a crucial step in the process. The impurity phase consists of retrograded starch, proteins and fat. In the past open tubular ceramic microfiltration modules and hybrid processes consisting of high speed separators and microfiltration have established themselves for the sweetener purification. Recently a new process consisting of a decanter and ultrafiltration spiral wound modules has been developed. Key aspects of this new process are a self-cleaning strainer before the ultrafiltration membranes to minimize fouling, the utilization of low fouling regenerated cellulose membranes to optimize membrane operations between cleaning cycles combined with an optimized cleaning method to maintain membrane performance. The overall concept resulted not only in higher sweetener quality but also in lower CAPEX and OPEX compared to established membrane based approaches. 5. OUTLOOK AND CONCLUSIONSOverall this presentation will highlight the importance of fouling and cleaning and their impact on CAPEX and OPEX of membrane plants. The approaches proposed can help to optimize the performance of membrane processes and thus support the long-term sustainability of membrane processes in the different industries.
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| 8. |
- Lipnizki, Frank, et al.
(författare)
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Key aspects of membrane plant operations related to fouling and cleaning in the food industry
- 2018
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Ingår i: Fouling and Cleaning in Food Processing 2018 : The food-water-energy challenge - The food-water-energy challenge.
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Konferensbidrag (refereegranskat)abstract
- Fouling is one the most important challenges to apply membrane technology on industrial scale in the food industry. Despite significant progress in understanding and preventing fouling and in developing appropriate membrane cleaning protocols, both fouling and cleaning remain key challenges in membrane plant operation in the food industry with a significant impact on membrane plants capital (CAPEX) and operating expenditures (OPEX) and thus the sustainability of membrane processes. The goal of this presentation is to show a relationship between fouling, pre-treatment, operation conditions and cleaning and how this can impact industrial membrane processes from a techno-economical point of view. The first part of the presentation will analyze the state-of-the-art of membrane cleaning in the food industry. The impact of e.g. number of cleaning cycle per day, cleaning cycle length and cleaning chemicals as well as type of cleaning chemicals and water quality will be discussed with regard to their impact on membrane plant OPEX and CAPEX. In the subsequent part of the presentation different approaches to reduce fouling and minimize the need for cleaning will be highlighted. The focus will be on the impact of pre-treatment but also on membrane module and membrane selection. The final part of the presentation will be an application study related to the removal of impurities e.g. retrograded starch, proteins and fat in the production of starch-based sweetener after liquefaction and saccharification of the starch. For this production step - which is often referred to as demudding - a new concept has been developed consisting of a decanter and membranes. The application study will demonstrate how the membrane part of the process was adjusted to overcome some serious fouling and thus capacity challenges encountered during the start-up of the first installation. The resulting new concept did not only control the fouling and minimized the cleaning but it also resulted in an improved sweetener quality. Overall the presentation will show approaches to reduce fouling and cleaning in order to support the long-term sustainability of membrane processes in the food industry.
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| 9. |
- Lipnizki, Frank, et al.
(författare)
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Membrane cleaning and its impact on plant operations and economics in food and biotech industry
- 2018
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Ingår i: Euromembrane 2018.
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Konferensbidrag (refereegranskat)abstract
- Membrane cleaning is an integrated part of the daily membrane plant operation in the food and biotech industry. However, the impact of membrane cleaning on the plant operations and economics are often neglected parameters in the development of new applications despite the fact that the cost for membrane cleaning is a dominating membrane operating expenditure apart from electricity. The aim of this paper is to provide some insights on the importance of membrane cleaning and how it can be optimised from an operating and economical point of view and to give an outlook how membrane cleaning can be further improved by moving from empirical understanding of cleaning to a more fundamental approach. Membrane cleaning and plant operationAlready during the test on lab and pilot scale cleaning has to be considered and if possible optimised. In the food and biotech industry a 4-hour-per-day-cleaning consisting of: flushing – caustic cleaning – flushing – acid cleaning – flushing – caustic cleaning – flushing is often standard. Reducing or combining steps - e.g. replacing two chemical steps by one enzymatic step - does not only reduce the amount of water and chemicals used but also the plant downtime and thus increases the daily plant capacity. Furthermore, cleaning at the appropriate time is another important factor to maximise plant capacity by replacing one cleaning cycle of four hours per day with two cleaning cycles of two hours per day. Additional, the impact of plant design, in particular continuous operations with sequential cleaning versus conventional cleaning of the complete plant will be discussed. Membrane cleaning and plant economics Membrane cleaning has a significant impact on operational (OPEX) and capital (CAPEX) expenditures of membrane plants. The key factors influencing the OPEX are costs for cleaning chemicals, rinsing water and wastewater. Furthermore, the length and frequency of cleaning has also an impact on the membrane life cycle and plant productivity, e.g. excessive cleaning can reduce the membrane life cycle significantly, while insufficient cleaning lead to lower average flux in the plant and thus a reduction of plant capacity. Optimising the cleaning cycles and cleaning frequency and will boost the average flux and increase the plant capacity. Consequently, optimising the cleaning protocol during the lab and pilot tests before the design of the plant can reduce the CAPEX of the plant and can thus have a significant impact on the overall process economics. Different approaches to improve membrane cleaning with regard to plant operations and economics will be demonstrated with application studies related to the food and biotech industry, i.e. for starch and protein applications. Outlook and conclusionsMost of the approaches to optimise membrane cleaning are currently of empirical nature. In order to overcome this, a deeper and more fundamental understanding of membrane cleaning is required using e.g. real time monitoring technologies such as ellipsometry, quartz crystal microbalance with dissipation monitoring (QCM-D) and confocal laser scanning microscopy (CLSM) combined with cleaning models. Overall, this paper will demonstrate the importance of membrane cleaning in the food and biotech industry and will provide an insight into how membrane cleaning can be optimised with regard to plant operation and economics.
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| 10. |
- Lipnizki, Frank, et al.
(författare)
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Membrane processes in the separation and utilisation of wood biomass in the context of the pulp and paper industry
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The recent developments in the field of biorefineries open new opportunities for the pulp and paper industry to diverse from classical carton and paper production to bio-based chemicals. The trend is thus to use the three key wood components hemicelluloses, lignin and cellulose as raw materials for production of a wide range of biochemicals. A key success factor is the integration of energy-efficient separation technologies to achieve price competitive products. Thus membrane filtration as an energy-efficient and highly selective technology can be an important unit of operation to support this trend.The presentation will demonstrate how membrane separation technology can be integrated in the concepts from the separation and purification of hemicelluloses, lignin and cellulose but also for the processing of side streams from the pulp industry and in the down-stream processing of the resulting biochemicals based on the wood biomass. Application and case studies will be presented for selected steps, e.g. ligninsulfonate from the sulfite pulping process or lignin in black liquor of the kraft pulping process.Furthermore, apart from the membrane opportunities in the production loops the focus will be also on opportunities in the water loops of these biorefinery concepts, e.g. reverse osmosis for evaporator condensate or membrane bioreactors for wastewater treatment.Overall, it will be shown that membrane processes as highly selective and energy-saving separation processes are in a strong position to become key units of operation in the concept of biorefineries.
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