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Title Synthetic natural gas (SNG) production based on biomass
Author Hafsteinsson, Erlingur Örn
Supervisor Elmegaard, Brian (Thermal Energy Systems, Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Clausen, Lasse Røngaard (Thermal Energy Systems, Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Ahrenfeldt, Jesper (Biosystems Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2011
Abstract The production of Synthetic Natural Gas (SNG) by thermal gasification is an attractive alternative to replace current fossil fuels. SNG is a biogas which consists mainly of methane (CH4). Using SNG as a transportation fuel (CNG) is a great way to reduce carbon dioxide (CO2) emissions. Producing SNG by gasification can be CO2 negative because the last upgrading step is to remove carbon as CO2. However, the removed CO2 can be captured and stored. Since the use of biomass will reduce CO2 emissions, the demand and price for biomass will increase. Therefore, it is essential to achieve high total efficiency in the biomass conversion process. This thesis will investigate how SNG can be obtained by two different plant designs with an Entrained Flow Gasifier (EFG), gas cleaning and methanation equipment. The difference between these plant designs is that one system has an extra input of hydrogen (H2). The objective of this thesis is to identify the plant with higher total efficiency and more feasibility. The feasibility is explored in both Denmark and Iceland. The literature review of the thesis consists of two designs: System 1 - A SNG plant based on biomass, and System 2 - A SNG plant based on biomass with extra input of hydrogen. Both systems have a dry biomass input of 1007MWLHV . This extra hydrogen comes from a process called Electrolysis of water(H2O) in an alkali Electrolyser (ELR). Dynamic Network Analysis (DNA) was used as modeling tool and the estimated values were found in literature. The main conclusion is that the total efficiency is higher for System 1. The total efficiencies on LHV basis, including the SNG produced, electricity consumed and produced, but excludes the pretreatment- and the transportation of biomass, are 73% for System 1 and 67% for System 2. System 1 also showed profit in both Iceland and Denmark while System 2 showed none. The reason why System 2 lacks high total eciency and profit is because of significantly high energy consumption of the ELR. Therefore, producing SNG from biomass is more efficient and feasible without the ELR.
Imprint DTU Mechanical Engineering
Pages 166
Series MEK-TES-EP-2011-12
Fulltext
Original PDF prod21323243706214_master_2011_s091261_1.pdf (2.88 MB)
Admin Creation date: 2011-12-13    Update date: 2011-12-13    Source: dtu    ID: 314399    Original MXD