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Gothenburg, Sweden

Lundberg V.,Chalmers University of Technology | Axelsson E.,Profu AB | Mahmoudkhani M.,Chalmers University of Technology | Berntsson T.,Chalmers University of Technology
Chemical Engineering Transactions | Year: 2012

Currently, Kraft pulp mills in Europe and North America are facing several challenges and have been forced to think along new products and new business areas. One opportunity is the conversion of chemical pulp mills into dissolving pulp mills by extracting hemicellulose prior to digesting via pre-hydrolysis. From the extracted wood chips, the more valuable dissolving pulp can be produced whereas the hydrolysate can be upgraded to high-value products. In this paper, pinch analysis is used to evaluate the consequences in the energy balance and utility system of a kraft mill converted into dissolving pulp production as well as to identify the potential for heat integration within the host mill itself, between the host mill and the pre-hydrolysis unit and with a hemicellulose upgrading process. The results show that proper heat integration within the host mill itself, and between the host mill and the pre-hydrolysis unit gives significant amounts of surplus steam which could be exported to a hemicelluloses upgrading process, used for power generation or to facilitate lignin extraction. Copyright © 2012, AIDIC Servizi S.r.l.

Lundberg V.,Chalmers University of Technology | Axelsson E.,Profu AB | Mahmoudkhani M.,Chalmers University of Technology | Berntsson T.,Chalmers University of Technology
Nordic Pulp and Paper Research Journal | Year: 2013

Conversion from kraft pulp into dissolving pulp production is an interesting development since it allows the production of a pulp with higher market value, as well as the production of valuable by-products, for example, hemicellulose, lignin, electricity, and/or heat. In this paper the major energy consequences of converting a modern kraft pulp mill into dissolving pulp production were investigated. Three critical choices for process configuration were examined: a) export the hydrolysate (extracted hemicellulose liquor) to an upgrading plant vs. combustion of the hydrolysate b) level of heat integration c) type of by-products produced (electricity or lignin) The results show that conversion into dissolving pulp production affects the energy balance of the mill considerably and can drastically affect the pulp production capacity of the mill, e.g. if the recovery boiler is the bottleneck. Sending the hydrolysate to combustion decreases the pulp production capacity, whereas lignin separation can debottleneck the recovery boiler and allow for higher pulp production. A higher level of heat integration increases the possibilities for debottlenecking and/or producing by-products. The conclusion is that an economic assessment is necessary in order to identify the most attractive process configuration. This assessment will be presented in the second part of this study. © 2004-2014 Nordic Pulp & Paper Research Journal.

Jones F.,Abo Akademi University | Jones F.,SP Technical Research Institute of Sweden | Bisaillon M.,Profu AB | Lindberg D.,Abo Akademi University | Hupa M.,Abo Akademi University
Waste Management | Year: 2013

Zinc (Zn) is a chemical element that has gained more attention lately owing to its possibility to form corrosive deposits in large boilers, such as Waste-to-Energy plants. Zn enters the boilers in many different forms and particularly in waste, the amount of Zn is hard to determine due to both the heterogeneity of waste in general but also due to the fact that little is yet published specifically about the Zn levels in waste. This study aimed to determine the Zn in Swedish waste fuels by taking regular samples from seven different and geographically separate waste combustion plants over a 12-month period. The analysis shows that there is a relation between the municipal solid waste (MSW) content and the Zn-content; high MSW-content gives lower Zn-content. This means that waste combustion plants with a higher share of industrial and commercial waste and/or building and demolition waste would have a higher share of Zn in the fuel. The study also shows that in Sweden, the geographic location of the plant does not have any effect on the Zn-content. Furthermore, it is concluded that different seasons appear not to affect the Zn concentrations significantly. In some plants there was a clear correlation between the Zn-content and the content of other trace metals. © 2013 Elsevier Ltd.

O Broin E.,Chalmers University of Technology | Mata T.,Chalmers University of Technology | Goransson A.,Profu AB | Johnsson F.,Chalmers University of Technology
Energy | Year: 2013

Utilising energy efficiency to lower energy demand in buildings is a key policy goal of the European Commission. This paper presents the results of bottom-up modelling to elucidate the impact of energy efficiency on the EU building stock up to 2050 under three different scenarios. The modelling is performed for eight individual EU countries and a ninth hypothetical entity that represents the remaining nineteen EU countries. The scenarios highlight the roles of different levels of efficiency improvements in the context of increasing floor area and the demand for energy services. From the results it can be concluded that the EC 2020 goals for primary energy savings can be met by focussing on a combination of minimum efficiency construction standards, improved conversion efficiency standards for final energy to useful energy, and a ≥2% annual improvement in end-use efficiency applied at the useful energy level. A comparison of the results obtained in the present study for Spain with the estimates of savings documented in the Spanish Energy Efficiency Action Plan indicate that the plan could lead to the closing of the energy efficiency gap for buildings in that country by 2020. ≥ 2013 Elsevier Ltd.

Goransson L.,Chalmers University of Technology | Goop J.,Chalmers University of Technology | Unger T.,Profu AB | Odenberger M.,Chalmers University of Technology | Johnsson F.,Chalmers University of Technology
Energy | Year: 2014

We evaluate the possibility to reduce congestion in the transmission grid through large-scale implementation of demand-side management (DSM) in the form of load shifting for the EU-27 countries, Norway, and Switzerland for Year 2020. A linear, cost-minimising, dispatch model that includes a DC load-flow description of the transmission system and a general representation of load shifting is used. It is assumed that the EU Member States fulfil the targets for Year 2020 in their national renewable energy action plans. In the model calculations, a reference case without load shifting is compared with cases in which the load shifting is 5%, 10%, 15% or 20% of the load. The possibility to shift load in time is added exogenously and economic incentives for DSM are not evaluated. Three types of congestion are identified: peak-load-hour congestion, low-load-hour congestion and all-hour congestion. Peak-load-hour congestion is reduced as the DSM share of the load increases, whereas low-load-hour congestion, which is typically associated with a high level of wind generation, persists at all the DSM penetration levels investigated. We show that all-hour congestion occurs between systems that have large differences in supply structure, and that the impact of DSM on all-hour congestion is low. © 2014 Elsevier Ltd.

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