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- Berglund Odhner, Peter, et al.
(författare)
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Biogas from lignocellulosic biomass
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Grontmij AB has cooperated with the University of Borås to evaluate the technological and economical possibilities for biogas production from substrates containing lignocellulose, such as forest residues, straw and paper. The state of knowledge regarding biogas production from cellulosic biomass has been summarized. The research in the field has been described, especially focusing on pretreatment methods and their results on increased gas yields. An investigation concerning commercially available pretreatment methods and the cost of these technologies has been performed. An economic evaluation of biogas production from lignocellulosic materials has provided answers to questions regarding the profitability of these processes. Pretreatment with steam explosion was economically evaluated for three feedstocks – wood, straw and paper – and a combination of steam explosion and addition of NaOH for paper. The presented costs pertain to costs for the pretreatment step as it, in this study, was assumed that the pretreatment would be added to an existing plant and the lignocellulosic substrates would be part of a co-digestion process. The results of the investigation indicate that it is difficult to provide a positive net result when comparing the cost of pretreatment versus the gas yield (value) for two of the feedstocks – forest residues and straw. This is mainly due to the high cost of the raw material. For forest residues the steam pretreatment cost exceeded the gas yield by over 50 %, mainly due to the high cost of the raw material. For straw, the production cost was similar to the value of the gas. Paper showed the best economic result. The gas yield (value) for paper exceeded the pretreatment cost by 15 %, which makes it interesting to study paper further.
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| 2. |
- Brandin, Jan, et al.
(författare)
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Bio-propane from glycerol for biogas addition
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, the technical and economical feasibility to produce higher alkanes from bio-glycerol has been investigated. The main purpose of producing this kind of chemicals would be to replace the fossil LPG used in upgraded biogas production. When producing biogas and exporting it to the natural gas grid, the Wobbe index and heating value does not match the existing natural gas. Therefore, the upgraded biogas that is put into the natural gas grid in Sweden today contains 8-10 vol-% of LPG. The experimental work performed in association to this report has shown that it is possible to produce propane from glycerol. However, the production of ethane from glycerol may be even more advantageous. The experimental work has included developing and testing catalysts for several intermediate reactions. The work was performed using different micro-scale reactors with a liquid feed rate of 18 g/h. The first reaction, independent on if propane or ethane is to be produced, is dehydration of glycerol to acrolein. This was showed during 60 h on an acidic catalyst with a yield of 90%. The production of propanol, the second intermediate to producing propane, was shown as well. Propanol was produced both using acrolein as the starting material as well as glycerol (combining the first and second step) with yields of 70-80% in the first case and 65-70% in the second case. The propanol produced was investigated for its dehydration to propene, with a yield of 70-75%. By using a proprietary, purposely developed catalyst the propene was hydrogenated to propane, with a yield of 85% from propanol. The formation of propane from glycerol was finally investigated, with an overall yield of 55%. The second part of the experimental work performed investigated the possibilities of decarbonylating acrolein to form ethane. This was made possible by the development of a proprietary catalyst which combines decarbonylation and water-gas shift functionality. By combining these two functionalities, no hydrogen have to be externally produced which is the case of the propane produced. The production of ethane from acrolein was shown with a yield of 75%, while starting from glycerol yielded 65-70% ethane using the purposely developed catalyst. However, in light of this there are still work to be performed with optimizing catalyst compositions and process conditions to further improve the process yield. The economic feasibility and the glycerol supply side of the proposed process have been investigated as well within the scope of the report. After an initial overview of the glycerol supply, it is apparent that at least the addition of alkanes to biogas can be saturated by glycerol for the Swedish market situation at the moment and for a foreseeable future. The current domestic glycerol production would sustain the upgraded biogas industry for quite some time, if necessary. However, from a cost standpoint a lower grade glycerol should perhaps be considered. In the cost aspect, three different configurations have been compared. The three alternatives are ethane production, propane production with internal hydrogen supply and propane production with external hydrogen supply. The results from the base case calculations can be viewed in table ES1. The base case calculations are based on carburating the upgraded biogas, before introducing it to the natural gas grid, from a 24 GWh biogas production facility. This means that the production units supply an acceptable Wobbe index of the final upgraded biogas. The annual cost in table ES1 is the yearly cost of carburating the gas at a 24 GWh biogas site. From the base case, it is obvious that there are differences in glycerol consumption depending on what alternative is chosen. There are also investment cost differences. To further investigate the volatility of the prices, a blend of Monte Carlo techniques were used to generate multiple data sets. The conclusions from the simulations were that the ethane producing facility has a stronger dependence on the feedstock; it is hence more sensitive to changes in the feedstock cost. It is however not as sensitive to changes in investment cost. If the production cost is compared to the cost of fossil LPG used today, the cost of the LPG is 0.43 kr/kWh. This does however not include the taxation and transporting the fuel. Adding the taxation alone will put an additional 0.25 kr/kWh on the cost, totalling 0.68 kr/kWh. This compares well with the calculated production cost of 0.78 kr/kWh for ethane and with the 50% percentile acquired from the Monte Carlo simulations of 0.94 kr/kWh.
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| 6. |
- Delsing, Jerker
(författare)
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Networked energy measurement and control in a natural gas grid
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The application of sensor network technology to gas metering and control in a gas distribution grid is discussed. Introduced by a brief overview of sensor network and sensor fusion ideas two different scenarios for applying networked sensors to gas metering and control are discussed. Possibilities for improved gas metering accuracy and improved customer communication are discussed. Such improvements will possibly result in new customer services that can be offered by the gas supplier and better energy efficiency. Based on this it is proposed a demonstration project. Here sensor networking applied to gas metering, the resulting services and related ideas will be tested and demonstrated at 10 customers. In addition investigations on customer realtions and future system cost and quality will be made. A very rough project cost estimate is 4.75 MSEK. To further investigate the possibilities of sensor networks in the gas distribution business also a research project is proposed. The research project will investigate new technology for estimating data on energy usage and system performance and system daignoses. Furhter architectures for suitable for networked sensors fusion in gas metering will be investigated. Project results will possibly provide more cost efficient system maintenance and improved system energy efficiency. A research project over 3.5 year is cost estimated to 5.82 MSEK.
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| 7. |
- Ljungberg, Sven-Åke, et al.
(författare)
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Detection and quantification of methane leakage from landfills
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SGC Rapport 204 Detection and quantification of methane leakage from landfills Sven-Åke Ljungberg, Jan-Erik Meijer, Håkan Rosqvist, Stig-Göran Mårtensson 2009 Landfills make a significant contribution to anthropogenic emission of greenhouse gases through emission of methane. Greater knowledge is needed about how methane leakage occurs and how to calculate its magnitude.The purpose of this project was to detect gas leakage and to measure and quantify methane emission from landfills using modern remote sensing techniques. In this project, a handheld laser instrument and an IR camera were used. The overall objective was to develop cost-effective methods for detecting and quantifying methane emissions from landfills. There are many methods available for measuring the methane concentration in air, both from close-up and from long distances. Combined with the use of a tracer gas, the methane emission from entire landfills can be measured relatively accurately. A number of methods are used to detect leakage from parts of landfill surfaces, but there are few methods for quantifying leakage from sub-zones.The laser instrument used in the project (Siemens AG, CT PS 8 laser system) can detect methane concentrations of ≥10 ppm, and has a maximum range of 30 m that can be extended to 150-200 m using reflective material as a backscatter surface. The concentration of methane is measured in ppm x m and can be stored in logs together with supplementary field data, such as landfill and atmospheric pressure, and weather and radiation conditions, for subsequent analysis after the fieldwork. The IR camera (FLIR ThermaCAM™ GasFindIR LW) has recently been introduced to the market, and was used in the project for detection and visualisation of gas emissions from landfills. The camera produces a thermal image of the gas emission. The thermal image data is stored digitally on a DVD unit connected to the camera.Field measurements with the laser instrument and the IR camera were carried out at seven Swedish landfills and two landfills in France. The investigated surfaces at the Swedish landfills were divided into different zones, such as top surface, slope, crest and toe of slope. The field measurements in France were taken over entire landfills. The methane emission varied between the different landfills in the project, and also between the different landfill zones. The results from repeated field measurements indicated that a landfill with a final cap and a successful gas recovery system produces barely measurable emissions. The weak points at a landfill are generally slopes, including crests and toes of slopes. Where the covering of the waste is inadequate, leakage often occurs at lift joints and in areas where waste protrudes through the cover. Other weak points are deficiencies in the gas recovery system. Leachate systems can lead landfill gas and thereby cause methane leakage.The laser instrument detects point source emission of methane by measuring the methane concentrations above the emission points. The IR camera detects and visualises the occurrence of methane emissions, and can be used to trace emission points and to illustrate the dispersion pattern of methane. Both laser and the IR instrument can be used to determine the exact position of the leakage source. Diffuse emission can only be detected if the emission is large, such as at the tipping face. Both the laser instrument and the IR camera are easy to use. The laser instrument can scan over an area of approximately 1 ha per hour. The smallest measurable point source emission gives a concentration level of approximately 60 ppm, which corresponds to a point source methane emission of the order of 35 – 290 m3 CH4/year.Scanning of the landfill surfaces showed that leakage could stop, increase or slow down. There are many reasons for these dynamics. Wind conditions, air pressure changes, and changes in the moisture content of the covering layer seem to be the most important. Along with wind velocity and variations in atmospheric pressure, moisture content in the ground is an important factor that affects methane emissions from landfill surfaces. Results from field measurements of the same feature/surface at different points in time and with different ground humidity showed that pores in the surface layer close when the moisture content is greater, reducing the landfill gas leakage. The large and sometimes rapid changes make it very difficult to get a picture of the distribution of the methane leakage over the landfill surfaces. Methane emissions were measured in different seasons, and also when the landfill surfaces had snow cover. The results showed that methane is emitted easily through porous snow. The same methane concentrations were recorded for GPS-fixed leakage features with and without snow cover. In the project, the chamber method was used to try to quantify methane leakage detected by the laser instrument. When chamber method results were correlated with the corresponding laser measurements, a relationship was evident. This produced a figure for emission. The relationship between the respective figures from laser and chamber method measurements was used to quantify the detected point source emissions at the French landfills. The total emissions detected with the laser instrument at the two landfills were estimated at 41 and 30 tons of methane respectively per year. These quantified methane emissions from detected points were smaller than the total emissions as reported by the landfill operators. The relationship indicates that it is the diffuse emission of methane that is predominant, and not the point source emission through holes, fissures, etc.If the objective is to produce a reliable measurement of gas emission from a landfill, the combination of laser/chamber method is not probably sufficiently accurate. However, if the objective is, for example, to determine and prioritise where measures should be taken at different landfill surfaces to reduce emission, the combination of laser and the chamber method is very usable. The measurement method tested was application-oriented, and the aim was that the measurements would provide information on which to base the planning and implementation of short- and long-term measures. Manuals were produced for the laser instrument and the IR camera, showing how the two instruments are to be used for detecting methane emissions from landfills.The project demonstrated how the laser instrument could be used by bouncing the beam off a simple reflector. Measurement using a beam path length of up to 200 m is possible. Examples of such applications are measurements over leachate ponds, beside a landfill and on parts of a landfill. Such measurements can give important information about emission conditions that are difficult to measure in any other way.Geoelectrical measurements have several areas of application for landfills, primarily in studies of groundwater pollution. In recent years, interest has also grown in investigating processes inside landfills. Based on results from previous studies, one of the aims of this project was to examine whether three-dimensional evaluation of resistivity measurements could be used to provide better measurements and understanding of the processes below the surface. According to previous studies, landfill gas movements can be visualised through geoelectricity measurements. In the experiment, resistivity was measured along eleven lines in an area 10 m x 10 m on a slope adjacent to a biocell reactor.The resistivity measurements showed results similar to or somewhat lower than the results shown in previous studies. High water content, ion content and high organic content can explain low resistivity, while high gas pressure in the ground partly explains high resistivity. It should also be noted that temperature variations affect resistivity. When the results from the resistivity measurements was compared with results from static chamber measurements and the laser instrument, no clear correlations were observed. The gas movements below the ground surface shown by resistivity measurements at the toe of the slope could not be confirmed with measurements above ground with the laser or static chamber methods. The results from the project show that combinations of laser, IR, chamber method and geo-resistivity measurements are a successful way to describe and map methane emissions from landfills. The mapping of emissions provides precise information useful for planning maintenance or improvement measures on landfill surfaces and gas recovery and leachate systems.
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| 8. |
- Brandin, Jan, 1958-, et al.
(författare)
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Green LPG
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The use of energy gases with renewable origins will become important with diminishing fossil resources. This as the infrastructure of the gaseous fuels is well built out and the distribution networks already exist. LPG is one of the most versatile fuels around, perfect for rural areas and in many other applications. The fossil origin of the fuel will, in today’s climate and environmental debate, however position it as a thing of the past and not part of the future energy supply. The technology and development performed under this and previous programs with the Swedish Gas Centre will however suggest a way to bridge this conception and make LPG a part of the future energy mix. A good starting point for two and three carbon energy gases is glycerine, with its three carbon backbone. The reason for focusing on glycerine is its benign chemical nature, it is:• Harmless from a toxic standpoint• Chemically inert• Non-corrosive• Relatively high energy density• Zero carbon dioxide emissions It is also readily available as the production of biofuels (from which glycerine is a sideproduct) in the world has increased markedly over the last 10 year period. This glut in the glycerol production has also lowered worldwide prices of glycerine.Since the key step in producing energy gases from glycerol is the dehydration of glycerol to acrolein, this step has attracted much attention during the development work. The step has been improved during the performed work and the need for any regeneration of the catalyst has been significantly reduced, if not omitted completely. This improvement allows for a simple fixed bed reactor design and will save cost in reactor construction as well as in operating costs of the plant. The same conclusion can be drawn from the combination of the two functionalities (dehydration and hydrogenation) in designing a catalyst that promote the direct reaction of 1-propanol to propane in one step instead of two. The experiments with the decarbonylation of acrolein to form ethane show that the catalyst deactivation rates are quite rapid. The addition of noble metal to the catalyst seems to improve the longevity of the catalyst, but the coking is still too severe to provide for a commercially viable process. It is believed that there is a possible way forward for the decarbonylation of acrolein to ethane; it will however require additional time and resources spent in this area. In this work it has been shown that all of the catalytic steps involved in the production of propane from glycerol have sufficient longterm stability and endurance and it is motivated to recommend that the project continues to pilot plant testing stage.
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