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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Exploring business models for export of environmental technology : Cases from Linkoping city, Sweden / Undersökning av äffarsmodeller för export av miljöteknik

Sadri, Sahar January 2013 (has links)
At present time, climate and energy issues are important subjects in the international market and environmental technology is a rapidly growing concept. Many companies in Sweden have developed much in-house knowledge in environmental technology. Therefore, they have great opportunity to export. In the sustainability perspective, export has not only benefits in the economic aspect, but also advantages for the environment. Development of appropriate business models is necessary for supporting environmental technology export.In this research an attempt was made to explore business model elements and offerings for export of environmental technology. The relevant theories in environmental technology characteristics, customization, product service systems and business models were used.The case studies included a Swedish municipality-owned company, its subsidiaries and a Swedish private company which was active in export. Empirical data were collected by conducting of interviews. The results reflect the business models and offerings of the studied cases. The analysis of cases provided findings for environmental technologies characteristics which have effect on export business models.Furthermore, six categories for making distinction among different elements of business models in literature were defined in this study. By analysis of the cases a new category which entailed new elements was added as the seventh category. The mentioned categories are useful in business model formulating for export of environmental technology.
12

The Possibility of Energy Recovery from Waste Material in Arges County, Romania

Nordström, Emma, Enochsson, Evelina January 2009 (has links)
Abstract Waste disposal is a global problem contributing to the ongoing climate change by large emissions of greenhouse gases. By using waste material as a resource instead of landfilling, the greenhouse gas emissions from landfills are reduced. Waste material can be used for waste incineration with energy recovery, thus decreasing the greenhouse gas emission from energy utilization by changing from fossil fuels to a partly renewable fuel. Arges County in Romania has severe problems with its waste material, mainly sewage sludge and waste from households and industries. As a consequence of the Romanian EU accession in 2007, Arges County is obliged to close its landfills for waste in a near future. A reconstruction of the wastewater treatment plant and an improved management of the sewage sludge residue are necessary in order to comply with EU standards. The requirements from the EU regarding waste disposal together with the existence of a district heating network in the residence city Pitesti, makes it interesting to investigate energy recovery from waste material in Arges County. Therefore, the goal of the study is to evaluate the possibility to extract energy from co-incineration of the waste material, sewage sludge and waste generated in Arges County. In order to reach this goal, the composition and quantities of the waste material is investigated. A suitable technology for the waste-to-energy (WTE) plant is proposed, based on the data of the waste material as well as on   established WTE technologies and their costs. It is assumed that the WTE plant will be implemented in 2020 and that all the generated waste will be incinerated. Furthermore, an environmental analysis is carried out, which presents the reductions of greenhouse gas emissions with the proposed WTE plant in comparison with the present system; including the management of waste and sludge and the district heating production, which is based on fossil fuels. The result shows that the waste material in Arges County has a calorific value of 7.5 MJ per kg, which is suitable for co-incineration of waste and sludge. The suggested WTE plant has the total power of 130 MW, annually recovering 620 and 330 GWh of heat and electric power respectively. The investment cost of the WTE plant is estimated to 226 million euro with a payback time of 8 years. The environmental analysis shows that the proposed system in comparison with the present system will decrease greenhouse gas emissions by 88 percent. A WTE plant appears to be a sound investment in Arges County and would sharply reduce the emissions of greenhouse gases in the county. However, some obstacles exist. Waste management is a new field in Romania and currently there are no WTE plants. Furthermore, the data used in this study concerning the quantity and composition of the waste, is uncertain and further studies are necessary before a WTE plant can be established.
13

Thermophilic and Hyper-thermophilic Anaerobic Co-digestion of Thickened Waste Activated Sludge and Fat, Oil, and Grease

Alqaralleh, Rania Mona Zeid 28 November 2018 (has links)
In this thesis, the anaerobic co-digestion of thickened waste activated sludge (TWAS) and, fat, oil and grease (FOG) was investigated as a method for TWAS:FOG treatment, stabilization, reduction and conversion to bio-methane gas as a valuable source of renewable energy. In the first phase, thermophilic and hyper-thermophilic anaerobic co-digestion of TWAS and FOG were investigated and compared. 20 – 80%FOG (based on total volatile solids) were tested using two sets of biochemical methane potential assays (BMP). Hyper-thermophilic co-digestion of TWAS with up to 60%FOG was shown to significantly increase the methane production and VS reduction as compared to the thermophilic co-digestion of the same TWAS:FOG mixture and as compared to the control (TWAS thermophilic mono-digestion). Both linear and non-linear regression models were used to represent the co-digestion results. In the second phase, the feasibility of the thermophilic and hyper-thermophilic co-digestion of TWAS and FOG were more investigated using lab scale semi-continuous reactors. The dual stage hyper-thermophilic reactor was introduced for the first time in this work for co-digesting TWAS and FOG. The dual stage co-digestion reactor was shown to significantly outperform the single-stage thermophilic mono-digestion reactor (the control) and the single-stage thermophilic co-digestion reactor at all three hydraulic retention times (HRTs) considered in the study namely, 15, 12 and 9 days. The dual-stage hyper-thermophilic co-digester digested up to 70%FOG at 15 days HRT without any stressing signs and produced a methane yield that was 148.2% higher compared to the control methane yield at the same HRT. It also produced a class A effluent at all three tested HRTs and positive net energy for 15 and 12 days HRT. The effects of microwave (MW) pretreatment, and combined alkaline-MW pretreatment on the co-digestion of TWAS:FOG mixtures with 20, 40 and 60% FOG were investigated in the third phase of this study. MW pretreatment at a high temperature of 175ᵒC was shown to be the most effective MW pretreatment option in solubilizing TWAS:FOG mixtures and in boosting the methane yield. It resulted in maximum solubilization for the 20%FOG samples and maximum methane yield for samples with 60%FOG. The combined alkaline-MW (NaOH-MW) pretreatment at a pH 10 showed to be an ineffective option for TWAS:FOG pretreatment before the anaerobic co-digestion process. In the fourth phase, the effects of the three selected pretreatments on the solubilization of TWAS and 20%FOG mixture on the molecular scale were investigated. The pretreatments used included: (i) MW pretreatment at 175ᵒC (since this was the best MW pretreatment condition according to the results of phase 3), (ii) hyper-thermophilic stage @ 70ᵒC and 2days HRT (effectively used in phases 1 and 2), and (iii) conventional heat at 70ᵒC. The analysis involved separation of the solubilized substrates after pretreatment using ultrafiltration (UF) at four different sizes (1, 10, 100 and 300 kDa). The results showed that each pretreatment method uniquely changed the particle size distribution. These changes showed to affect the biodegradability of substrates with different class size. Finally, two brief studies were performed using BMP tests to investigate the feasibility of FOG addition as a biogas booster in TWAS anaerobic digestion. First, the effect of FOG addition on TWAS and organic fraction of municipal solid waste (OFMSW) co-digestion was tested using hyper-thermophilic BMP tests. The addition of 30% FOG (based on total volatile solids) was shown very effective in improving the methane yield. The 30% FOG addition to TWAS:OFMSW mixture resulted in 59.9 and 84.4% higher methane yield compared to the methane yields of TWAS:OFMSW and TWAS samples, respectively. Second, the feasibility of using the soluble part of FOG (L-FOG) as a co-digestion substrate to increase the biogas production from the thermophilic digestion of TWAS was investigated. The results showed that co-digestion of TWAS and 20 to 80% (based on total VS) of L-FOG using a substrate to inoculum ratio (S/I) of 1 improved the biogas yield by 13.5 to 83.0%, respectively. No inhibition was reported at high L-FOG %.
14

Estudo comparativo de processos de gaseificação de resíduos sólidos urbanos no Brasil. / Sem título em inglês.

Ramires Menezes da Silva Araújo 21 June 2016 (has links)
Os resíduos sólidos urbanos (RSU) no Brasil são na grande maioria direcionados para aterros e lixões a céu aberto, onde ocupam grandes áreas, geram transtornos relacionados ao trafego aéreo, emitem gases responsáveis pelo efeito estufa sem o devido reaproveitamento energético. Como alternativa para a minimização do passivo ambiental causado pelos RSUs e potencial reaproveitamento energético propõe-se um estudo comparativo de processos de gaseificação desses resíduos em diferentes meios gaseificantes. A modelagem e simulação dos processos foram feitas aplicando-se o método de minimização da energia livre de Gibbs não estequiométrica. Considerou-se a quantidade de resíduo sólido urbano destinado da sub-região de Campo Limpo - São Paulo - e a sua composição representativa expressa pelo método ultimate-analysis. O processo de gaseificação foi implementado em simulador de processo e o estudo se concentrou nas etapas do processo de gaseificação, investigando-se a ação dos seguintes meios gaseificantes: ar, vapor e mistura ar e vapor. Os principais resultados analisados foram a composição do produto da gaseificação e o potencial energético do produto. / The major destiny of Municipal Solid Waste (MSW) in Brazil is landfill. These sites occupy large areas; most of them are open, being simply disposal areas. This situation causes several problems ranging from greenhouse gases to air traffic jeopardizing. The use of MSW in energy generation addresses these problems, once it is one of most promising solutions to MSW treatment. This work is the study of gasification from the energy potential. It was carried out through minimization of Gibbs energy in a process simulator. The MSW considered was the one from area of Campo Limpo in São Paulo city. Its composition was expressed by ultimate analysis. The use of different gasification agents included air, steam and their mixtures was analyzed. The results were HHV and composition of generated gases.
15

Barreiras e facilitadores para o planejamento e implantação de usinas de recuperação de energia de resíduos sólidos urbanos / Barriers and facilitators in the process of planning and building waste to energy plants of municipal solid waste

Sami Grynwald 08 October 2014 (has links)
Historicamente, o Brasil possui dificuldades para equacionar a questão da disposição dos Resíduos Sólidos Urbanos (RSU) gerados pela população. Durante anos, eles foram depositados em locais inapropriados, gerando uma série de problemas sociais e ambientais. O gerenciamento dos RSU requer ações diversificadas e complexas, devido à quantidade, composição e localização de geração. O principal desafio é encontrar soluções ambientalmente responsáveis, socialmente adequadas e economicamente viáveis. Presentes em diversos países, as Usinas de Recuperação de Energia (URE) produzem energia elétrica por meio de uma fonte renovável, que elimina os efeitos adversos de sua disposição inadequada e reduz o volume dos resíduos destinados aos aterros. Mas, no Brasil, a implantação das URE ainda enfrenta um grande desafio, pois mesmo com a existência de diversos estudos, até hoje não há nenhuma em operação no país. Com base na importância das URE tanto para o equacionamento de questões relativas à disposição final dos RSU quanto como solução conveniente para suprimento de energia elétrica, este trabalho visa entender como a utilização de conceitos e técnicas de gerenciamento de projetos podem favorecer a superação de barreiras e o aproveitamento de facilitadores do processo de planejamento e implantação das URE de RSU. / Historically, Brazil has difficulties disposing of the municipal solid waste (MSW) generated by its population. For years, it was disposed in inadequate places, generating a series of social and environmental problems. Managing the MSW requires diverse and complex actions, depending on the quantity, composition and location. The main challenge is finding environmentally responsible, socially adequate and economically viable solutions. Present in many countries, the waste to energy plants (WTE) are able to produce electricity through a renewable source, which eliminates the adverse effects of its inadequate disposal, as well as reduces the volume of waste destined to landfills. However, in Brazil, the WTE implantation is still a great challenge, even with various studies done, none is operating in the country. Regarding the WTE importance, considering it a solution for the MSW final disposal as well as a convenient alternative for electricity supply, this study aims to understand how concepts and techniques of project management can help overcome barriers and use facilitators in the process of planning and building a WTE of MSW.
16

Je Waste to Energy alternatívou? / Is Waste to Energy an alternative?

Hanigovský, Štefan January 2008 (has links)
The world waste hierarchy is changing under the pressure of growing population, strict standards of living and environmental standards, as well as new technological experiences. Strengthening of environmental standards in Europe leads to restraining the most used and cheapest waste treatment method - landfilling. The limitation of landfilling will force the countries to search for alternative treatments. This diploma thesis is supposed to give certain conclusion whether the incineration of waste with gaining energy (waste-to-energy) can be the right way how to deal with waste in the future. Current market position of waste-to-energy is being examined in selected European countries, focusing on whole environmental, economic and social aspects of using this technology. Incineration as commercially proven state-of-the-art technology is still having problems entering the new markets even if the technology with its sophisticated approach shows a great environmental service. The results of the examinations show the potential for Czech Republic, as well as other countries where WTE is not utilized yet.
17

Moderní jednotka pro energetické využití odpadů o střední kapacitě / Up-to-Date Medium Capacity Waste-to-Energy Unit

Krišpín, Jan January 2017 (has links)
The submitted Master Thesis deals with the technological/mechanical solution of an up-to-date medium capacity waste-to-energy plant. Operational requirements and basic parameters related to a concrete region are specified in the introduction of the Thesis. This is supplemented by a flow-sheet of the plant with the description of main process subsystems. To meet the goals of the Thesis basic balance information is summarized and related schemes included. These data represent principal inputs for the on-site plant as well as basic parameters for the design of key equipment. These pieces of equipment are schematically drawn including their basic parameters and a description of construction. All the available innovative solutions are taken into account. The Thesis provides also a technical-economic analysis for being able to evaluate the overall project.
18

Parní turbína pro spalovnu odpadu / Steam Turbine for Waste to Energy

Hodonský, Lukáš January 2018 (has links)
The thesis deals with the design of the steam turbine for a waste incinerator. First, the concept and design of the machine is discussed. Following part is the steam turbine thermodynamics calculation, which is the main part of the thesis. My work also contains calculation of axial force and a simplified calculation of the gearbox. The design sections of individual modules and drawing of a disposition of a steam turbine are made on the based of the calculation.
19

Optimized WtE Conversion of Municipal Solid Waste in Shanghai Applying Thermochemical Technologies

Dai, Siyang January 2016 (has links)
Thermochemical technologies have been proven effective in treating municipal solid waste (MSW) for many years. China, with a rapid increase of MSW, plans to implement more environmental friendly ways to treat MSW than landfill, which treats about 79 % of total MSW currently. The aim of this master thesis was to find out a suitable thermochemical technology to treat MSW in Shanghai, China. Several different thermochemical technologies are compared in this thesis and plasma gasification was selected for a case study in Shanghai. A model of the plasma gasification plant was created and analysed. Other processes in the plant including MSW pre-treating and gas cleaning are also proposed. By calculating the energy balance, it is demonstrated that plasma treatment of 1000 ton/day MSW with 70 % moisture reaches an efficiency of 33.5 % when producing electricity, which is higher than an incineration WtE plant (27 % maximum) and a gasification WtE plant (30 % maximum). Besides of the efficiency comparison, costs and environmental impacts of different technologies are also compared in this paper. The result indicated that given the characteristics and management situation of MSW in Shanghai, plasma gasification is a better choice to treat MSW in Shanghai.
20

An assessment of the potential for using gasification technologies for thermal applications in Uganda’s small-scale agro-industries

Mutyaba, Job January 2014 (has links)
Energy is one of the biggest costs of production in industries and Small scale industries in Uganda are faced with a big burden due to the high energy costs they incur in their operations. Due to the high costs associated with electricity and fossil fuels, biomass energy continues to supply the bulk (81%) of industrial energy demands. However unsustainable harvesting of tradition biomass fuels (firewood and charcoal) is leading to depletion and causing a hike in prices of this important energy source. This study determined current thermal loads for 4 small scale industries, the costs of the fuels used, possible agro waste replacement options and economic comparisons of gasification using these fuel alternatives. Questionnaires, interviews and quantitative measurements of the various parameters were undertaken to establish current fuel usage and costs. Economic and emission reductions analysis were conducted using RETScreen energy planning tool. Results of indicated that the current combustion and heat transfer devices are very inefficient leading to intensive energy demands. Proposed gasifier systems of the range of 30 kW to 100kW fuel power, would cost between US$ 6,156.35 and US$20,371.20. It was further established that installing gasifiers and incorporating agro wastes in the fuel mix (60%) would greatly reduce expenditure on fuels with pay back periods ranging from 0.4 – 3 years. Risk analysis further showed that fuel costs and operations and maintenance would attract the highest risk to the net present value of each proposed gasifier installation. From these results, it was recommended that gasification coupled with use of agro wastes provides viable cheap alternative for small scale industrial thermal energy needs

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