Suchergebnisse

Woody biomass is an abundant renewable energy resource in Sweden, and the Swedish government has been promoting research and development programs for the exploitation of this resource as a mean to meet the targets on the reduction of the carbon dioxide emissions from the industrial, energy and transportation sectors. This thesis aims at expanding the knowledge on the efficient utilization of the available woody biomass, so that a larger amount of this renewable resource can be used for energy purposes. The thesis presents a collection of studies following the main two policies that have been identified for the reduction of carbon dioxide emission, i.e. the implementation of measures improving energy conservation and efficiency and a deep decarbonization of the energy sector. Process integration and optimization techniques are applied to forest industry sites in order to improve the resource and energy efficiency, the benefits of the integrated design configurations being evaluated by both technical and economic analyses. The integration of woody biomass with intermittent renewable energy sources is also studied in order to enable a large share of non-fossil sources in the energy mix.The results of the investigations show a significant potential for improving biomass resource utilization in the forest industry sites strictly from the energetic point of view. Optimizing the process integration in sites including Kraft pulp and paper mills and/or sawmills and a dedicated common CHP system can lead to a much greater power generation for the same input biomass and for the same production volume, or to large amounts of excess heat to be used in nearby processes or district heating, or even to the re-routing of part of the input biomass to other conversion processes (e.g. lignin separation and hemicellulose fermentation to produce biofuels). The operational profit of the site is consequently increased, but, when the investment costs are considered, some form of subsidies to the "green" byproducts are usually still required to make the integrated design configurations economically viable. The integration of woody biomass with intermittent renewable energy sources can result in an increased efficiency of hybrid power generation plants (e.g. with concentrated solar thermal collectors), and on a large scale it could facilitate the decarbonization of the energy sector with the fundamental contribution from power-to-X technologies in order to produce chemical fuels from the excess intermittent electricity. These technologies would be clearly incentivized by a carbon tax, but the benefit deriving from the large volumes of captured CO2 that are required for the synthesis of chemical fuels through co-electrolysis should also be taken into account. Keywords: Forest industry, process integration, pinch analysis, HEATSEP method, optimization, CHP system, techno-economic, biorefinery, intermittent renewables. ; Godkänd; 2016; 20160412 (senmes); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Sennai Mesfun Ämne: Energiteknik /Energy Engineering Avhandling: Process Integration to Increase Woody Biomass Utilization for Energy Purposes Opponent: Associate professor Francesco Fantozzi, Department of Engineering & Biomass Research Center, University of Perugia, Perugia, Italien. Ordförande: Professor Andrea Toffolo, Avd för energivetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå. Tid: Torsdag 9 juni, 2016 kl 14.00 Plats: E632, Luleå tekniska universitet

Indonesia aims at reducing the dependence on oil import by liquid biofuels consumption (i.e., biodiesel and bio-ethanol) in industry, transport and power sectors. The palm oil industry has played significant role in the development of biodiesel in the country producing crude palm oil (CPO) and palm fatty acid distillate (PFAD) based biodiesel. Opportunity exists for the industry to contribute to the development of bio-ethanol program by utilising the lignocellulosic biomass such as the empty fruit bunches (EFB). This study evaluates the potential of liquid biofuels production from oil palm biomass and the domestic demand for biofuels as per biofuel blending target set by the Indonesian government. The existing infrastructures as well as the investment opportunity of each type of biofuel are analyzed. While technology for biodiesel production is proven at large scale, the bio-ethanol production from EFB is not commercialized yet. The study shows that meeting the biodiesel blending target is at risk if Indonesia continues to solely reliance on the production of CPO and PFAD based biodiesel. Palm oil industry can produce nearly 7 billion litres biodiesel from CPO and PFAD in 2025 but the biodiesel domestic demand is 30% higher. The bio-ethanol program faces higher risk. EFB based ethanol through gasification and synthesis of alcohol can contribute to around 13% of the target in 2025, however the infrastructure is not ready yet. Feedstock diversification to produce liquid biofuels should be prioritized. We recommend a review of the current plan to a more achievable targets or prolong the timeline in order to secure domestic biofuels demand while continuing export. The study provides database for future modelling exercise on multi-period optimization study of palm biofuels supply chain in Indonesia in a geographically explicit way. ; QC 20190903