| 1. |
- Bertilsson, F, et al.
(författare)
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CO2 utilization options .1. An emission assessment framework
- 1996
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 37:12, s. 1725-1731
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Tidskriftsartikel (refereegranskat)abstract
- The utilization of CO2 in various products and services must be carefully assessed in order to achieve reduced CO2 emissions and simultaneously to add to the net economic benefit of society. In this paper, a framework for the assessment of CO2 utilization options in the chemical industry is outlined in which the total CO2 emission is estimated in four steps. First, the processes under study are surveyed to establish the consumption of different raw materials (reactants). Second, the CO2 emission due to the content of fossil carbon in the reactants is determined, i.e. the material-related emission. Third, the CO2 emission related to energy consumption in the studied processes is estimated, i.e. the direct energy-related emission. Fourth, the CO2 emission related to energy consumption in the reactant production processes is estimated, i.e. the indirect energy-related emission. Copyright (C) 1996 Elsevier Science Ltd
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| 2. |
- Bertilsson, F, et al.
(författare)
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CO2 utilization options .2. Assessment of dimethyl carbonate production
- 1996
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 37:12, s. 1733-1739
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the potential to reduce CO2 emissions from dimethyl carbonate production by switching from the traditional phosgene-based production to a urea-based CO2 utilization process is assessed. The total CO2 emission for each process is estimated, including emissions related to the carbon content of the products, energy consumption in the production process, and energy consumption in the production processes of the required reactants. Implementation of the CO2 utilization process probably will reduce total CO2 emissions. However, in order to achieve substantially reduced CO2 emissions, serious consideration must be given to the optimization and design of the CO2 utilization process. Furthermore, the fuel-mix employed is one of the factors that influences the total CO2 emission the most. Copyright (C) 1996 Elsevier Science Ltd
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| 3. |
- Börjesson, Pål
(författare)
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Emissions of CO2 from Biomass Production and Transportation in Agriculture and Forestry
- 1995
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 37:6-8, s. 1235-1240
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Tidskriftsartikel (refereegranskat)abstract
- Net CO2 emissions have been calculated for the production and transportation of biomass in Swedish agriculture and forestry, using fossil-fuel-based energy inputs. An analysis of how a transition from a fossil-fuel-based energy system to a CO2-neutral biomass-based system would affect the energy efficiency in biomass production and transportation, has also been carried out. Production and transportation of short-rotation forest (Salix), straw, and logging residues exhibited the lowest CO2 emissions per unit energy delivered, equal to about 50% of those from perennial ley crops and 10 to 30% of those from annual food crops. Compared with CO2 emissions from a complete fuel-cycle for coal, net emissions of CO2 from Salix production, including transportation 50 km by truck, are 35 to 40 times lower when fossil-fuel inputs are used. Future increases in yield and technological development are estimated to reduce net CO2 emissions from biomass production by 30 to 50% in a fossil-fuel-based energy system around the year 2015. A transition from a fossil-fuel-based, to a CO2-neutral biomass-based energy system around 2015, is estimated to increase the energy input in biomass production and transportation by about 40% and 20%, respectively, resulting in a decreased net energy output from biomass production (including transportation) by about 4%.
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| 4. |
- Gustafsson, Stig-Inge
(författare)
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Carpentry factory and municipal electricity loads
- 1998
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 39:3-4, s. 343-347
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Tidskriftsartikel (refereegranskat)abstract
- Load management of electricity loads has received more interest in recent years. At least in Sweden, this is natural because of a rather cheap energy price, while at the same time, the demand charge is high. If a company could save the precise kWh that build the peak demand, then these would have a value of more than 200 times the off-peak kWh. This paper deals with monitored electricity data for two carpentry industries and one municipality, both situated in the south of Sweden. The ideal ! situation would be if the industry could reduce their peak demand and, at the same time, reduce the peak for the utility. Both participants would, in that case, save money, and the payback time for load management equipment would decrease substantially. If, however, a load management system at the carpentry transfers kWh to peak hours for the utility, the industry will save money, while the utility gets higher costs. The result of the study is that the Swedish electricity rates in use today are a very poor means of encouraging worthwhile load management, and often, they even aggravate the situation.
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| 5. |
- Gustafsson, Stig-Inge, 1948-
(författare)
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Energy usage and conservation in surfacing lines
- 2000
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Ingår i: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 41:15, s. 1649-1669
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with energy usage and conservation for a surfacing line in a carpentry factory. In this line, wood panels are coated with paint in a highly automated fashion. The products vary in shapes and the way they shall be coated, and therefore, a number of machines are present in the line which is about 100 m long. Sanding machines, roller coaters, dryers etc. are installed, and all machinery uses electricity for their operation. There are, however, other equipments coupled to the line. One example is the wood dust transportation system, and another is the steam system used for heating purposes. By use of a number of electricity meters, monitoring ventilation flow rates etc., it has been possible to analyze how much energy is used in the surfacing line and also to propose measures to reduce this amount.
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| 6. |
- Gustafsson, Stig-Inge, et al.
(författare)
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Heat Accumulators in CHP Networks
- 1992
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 33:12, s. 1051-1061
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Tidskriftsartikel (refereegranskat)abstract
- In a Combined Heat and Power (CHP) network, it is sometimes optimal to install a device for storing heat from one period of time to another. Several possibilities exist. If the electricity demand is high, while at the same time the district heating load is too small to take care of the heat from the CHP plant, it could be optimal to store heat from peak periods and discharge the storage under off-peak. It might also be optimal to store heat during off-peak and use it under the district heating peak load. The storage is then used for decreasing either the district heating demand or for decreasing the electricity load used for space heating. The paper shows how a mixed integer program is developed for use in the optimization process. As a case study, the CHP system of Malmö, Sweden, is used. Further, a sensitivity analysis is elaborated in order to show how the optimal solution will vary due to changes in certain input data.
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| 7. |
- Lyngfelt, Anders, 1955, et al.
(författare)
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Methods for reducing the emission of nitrous oxide from circulating fluidized bed combustion
- 1996
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 37:6-8, s. 1297-1302
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Tidskriftsartikel (refereegranskat)abstract
- Abstract - Two methods for the reduction of nitrous oxide emissions, afterbuming and reversed air staging, are investigated in a 12 MW circulating fluidized bed boiler. With afterburning the N2O emission can be reduced by 90% or more, using an amount of secondary fuel corresponding to 10% of the total energy input. With reversed air staging it is possible to reduce the emission of N2O to one fourth (25 ppm), without significantly affecting the other emissions. With reversed air staging no secondary air is used in the combustor and an air-ratio of about unity is maintained throughout the combustion chamber. Air for final combustion is added in the cyclone outlet.
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| 8. |
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| 9. |
- Rolfsman, Björn, 1971-
(författare)
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Optimal supply and demand investments in municipal energy systems
- 2004
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Ingår i: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 45:4, s. 595-611
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Tidskriftsartikel (refereegranskat)abstract
- In many municipalities, there are district heating networks, which are quite commonly supplied by combined heat and power plants (CHP). A district heating network contains buildings of different types. In this paper, one such municipal energy system is analysed. In order to provide space heating and domestic hot water, investments could be made on the supply side in power plants, or on the demand side in the buildings, for example in the form of extra wall insulation. The electricity from the CHP plants is supplied to the municipality but can also be sold to the electricity market, and electricity can, of course, also be bought from the market. The variation in price on the spot market over any given day is significant. The need for district heat in the building stock also varies, for example due to climatic conditions. The energy system in the case study is analysed with a mixed integer linear programming model. The model has 3 h time steps in order to reflect diurnal variations, and an entire year is analysed. A case study is presented for the city of Linköping in Sweden. On the demand side, the options are: extra wall insulation, extra attic insulation and better types of windows. The building stock is divided into nine categories. © 2003 Elsevier Ltd. All rights reserved.
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| 10. |
- Sundberg, Gunnel, et al.
(författare)
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Investments in combined heat and power plants : Influence of fuel price on cost minimised operation
- 2002
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Ingår i: Energy Conversion and Management. - 0196-8904 .- 1879-2227. ; 43:5, s. 639-650
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Tidskriftsartikel (refereegranskat)abstract
- Liberalisation of the electricity market and governmental politics influence heat and power supply in Sweden, like in many other countries. In this paper, the impact of subsidies and fuel and electricity costs on a representative Swedish district heating system is analysed. The energy system model MODEST (model for optimisation of dynamic energy systems with time dependent components and boundary conditions) was used to optimise investments and operation for heat and power production plants. At higher electricity prices, combined heat and power introduction may be profitable in the studied system. With current fuel prices, a natural gas fired combined cycle would primarily be favourable. A lower woodchips price and a governmental grant would make cogeneration with a biomass fired steam cycle more beneficial. © 2002 Elsevier Science Ltd. All rights reserved.
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