| 1. |
- Lucas, Carlos, et al.
(författare)
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Mathematical model of biomass gasification using high temperature air in fixed beds
- 2007
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Ingår i: Progress in Computational Fluid Dynamics, An International Journal. - 1468-4349 .- 1741-5233. ; 7:1, s. 58-67
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model has been formulated for predicting the main chemical and physical processes taking place during the fixed-bed gasification of biomass fuels using high temperature air (up to 1000 degrees C). Predicted gas species concentrations profiles and their maximum values are in good agreement with measurements. The results also show that when the temperature of feed gas (air) is increased a higher gasification rate, higher molar fractions of fuel gases (CO, H-2 and CmHn) are obtained, thus resulting in a higher LHV. At a high flow rate of the feed gases, the peaks of the fuel gas concentrations are slightly increased, and the gasification rate is strongly increased. A smaller particle size of the biomass fuels leads to higher peak values of the fuel gas species molar fractions, and a more stable gasification zone for a relatively long period of time.
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| 2. |
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| 3. |
- Blasiak, W., et al.
(författare)
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Combustion performance improvement of grate fired furnaces using Ecotube system
- 2006
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Ingår i: Journal of the Energy Institute. - : Informa UK Limited. - 1743-9671 .- 1746-0220. ; 79:2, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the main features, advantages and an evaluation of applications of an 'Ecotube' technology for combustion improvement and emission reduction. The sensitivity of the Ecotube locations in a combustion chamber and the injection angle of jets on the Ecotube have been analysed numerically. A municipal solid waste incinerator and a coal fired boiler are the focus of this work. A definition of the heat release distribution ratio is proposed to identify the heat release inside the upper furnace of boilers or incinerators. Results show that an Ecotube system allows a far more uniform heat release, lower CO and NOx emissions, and a more uniform temperature distribution, thus a longer life of the furnace chamber. Additionally, the combustion reaction zone occupies as high as 45% of the whole combustion chamber using an Ecotube system, similar to 40% higher than a conventional multijet mixing system.
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| 4. |
- Blasiak, W., et al.
(författare)
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Flameless oxyfuel combustion for fuel consumption and nitrogen oxides emissions reductions and productivity increase
- 2007
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Ingår i: Journal of the Energy Institute. - : Informa UK Limited. - 1743-9671 .- 1746-0220. ; 80:1, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- In order to achieve very low emission of nitrogen oxides, a 'flameless' combustion process that uses oxygen, the so called 'flameless oxyfuel' combustion, has been developed. This new combustion technology is characterised by a lower temperature flame, more uniform temperature distribution and low concentrations of oxygen as well as nitrogen inside the combustion chamber. This work presents a description and the main features of the flameless oxyfuel combustion, the effect of flame structure and temperature on the heat transfer, the comparison of flameless oxyfuel and flameless air fuel combustion results of laboratory tests of new type of flameless oxyfuel burner, as well as examples of industrial applications. This newly developed and applied combustion technology guarantees fuel consumption reduction ( thus CO2 reduction), increase in productivity as well as drastic reduction of nitrogen oxides emission when applied, for example, to thermal treatment processes of wastes, and to the recovery of zinc bearing feed in a rotary kiln.
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| 5. |
- Blasiak, Włodzimierz, et al.
(författare)
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Oxyfuel flameless combustion for fuel consumption and nitrogen oxides emissions reductions and productivity increase
- 2006
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Ingår i: A and WM, Annual International Conference on Incineration and Thermal Treatment Technologies. - 0923204849 - 9780923204846 ; , s. 668-685
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Konferensbidrag (refereegranskat)abstract
- During last years development of combustion technology focussed the following main aims: fuel consumption reduction, nitrogen oxides emission reduction, increase of productivity and product quality. Fuel savings up to 50%, thus also CO 2 emission reduction, was achieved by replacing combustion air with oxygen. To achieve very low emission of nitrogen oxides (NOx) the new combustion technology is characterised by: lower temperature of flame, more uniform temperature distribution and low concentration of oxygen as well as nitrogen inside combustion chamber. Because in such combustion a flame is replaced by a large chemical reaction zone and thus often is not visible the process was named as flameless combustion. Flameless combustion process with use of oxygen, so called oxyfuel combustion, as well as its technical application is subject of this work. This work presents description and main features of the flameless oxyfuel combustion, results of laboratory tests of new type of flameless oxyfuel burner, as well as examples of industrial applications. This newly developed and applied combustion technology guarantees fuel consumption reduction (thus CO 2 reduction), increase of productivity as well as drastic reduction of nitrogen oxides emission when applied for example to thermal treatment processes of wastes, and a recovery of zinc-bearing feed in a rotary kiln.
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| 6. |
- Donaj, Pawel, et al.
(författare)
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Kinetic study of decomposition of ASR residues after pyrolysis in inert and oxidative atmosphere
- 2009
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Ingår i: International Thermal Treatment Technologies (IT3) & Hazardous Waste Combustors (HWC) Joint Conference 2009. - 9781615671830 ; , s. 465-483
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Konferensbidrag (refereegranskat)abstract
- The kinetic studies on solid residues after pyrolysis from ASR (Automobile Shredder Residue) originated from STENA Metall AB have been performed with the use of thermogravimetry analysis TGA. The char after microwave pyrolysis has been pyrolyzed and combusted in the presence of helium and air respectively. The TG experiments have been performed with heating rate of 10, 20, 40, 60 and 100deg/min. The influence of heating rate for decomposition rate and the char reactivity was also analyzed. Three different decomposition peaks have been identified for pyrolysis process in the range of temperatures 230-430, 400-500 and 680-850°C, respectively. The activation energy (E act) and pre-exponential (frequency) factor (A) were calculated from the DTG curves using Coats and Redfern (C&R) method and Doyle's (D), based on the assumption of an independent, parallel first order Arrhenius-type global kinetic model. The kinetic data were also obtained for small lab scale gasification process of ASR pyrolysis residues. The mass loss and the heating of sample are recorded. It was proved, that the char's heating rate plays a significant role in the conversion rate as well in the char reactivity. The relatively high ignition temperature of 630°C would require the steam temperature to be well above 800°C. Thus, reasonable would be to use high temperature steam gasification for treating ASR residues after microwave pyrolysis.
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| 7. |
- Kantarelis, E., et al.
(författare)
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Sustainable valorization of plastic wastes for energy with environmental safety via High-Temperature Pyrolysis (HTP) and High-Temperature Steam Gasification (HTSG)
- 2009
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 167:1-3, s. 675-684
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Tidskriftsartikel (refereegranskat)abstract
- In the present study the energetic valorization of electric cable shredder residues (mixed plastics) has been investigated. Thermochemical conversion by means of High-Temperature Steam Gasification (HTSG) and High-Temperature Pyrolysis (HTP) was studied. The effects of temperature and reaction time - process parameters - were investigated. Comparison of the results showed that HTSG seems a more suitable process in terms of produced syngas quality (64%. v/v and 13 MJ/Nm(3)) than HTP because of higher H-2 yield and lower tar content.
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| 8. |
- Kubik, Katarzyna, et al.
(författare)
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Assessment of ASR treatment using pyrolysis and reforming of its residences for small scale electricity generation systems
- 2008
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Ingår i: Air and Waste Management Association. - 9781605603797 - 9781605603797 ; , s. 717-726
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Konferensbidrag (refereegranskat)abstract
- Due to the increased manufacturing of new vehicles, older ones the so called end-of-life vehicle's (ELV) are being disposed more frequently. The EU ELV directive (entered into force 21/10/2000) sets targets and objectives that must be obeyed by the member states. Under this directive from 01/01/2006 for all ELV, the reuse and recovery rate should be min. 85% (by weight) and min. 80% (by weight) rate of recycling. From 01/01/2015 for all ELV, the reuse and recovery rate should be min. 95% (by weight) and min. 85% (by weight) rate of recycling. Because of the lack of a cost-effective technology to recycle this waste, it is mostly land filled, smaller amounts are incinerated. In this work, basing on the reviewing of the available technological methods, a new thermal treat system for ASR is proposed: Firstly, a microwave pyrolysis of ASR is used. During this pyrolysis process, metals will be successfully recycled, and also generate by-products such as pyrolysis gas, oil, and char. These by-products will be further reformed using high-temperature steam gasification to generate high-purity synthetic gas, which will be used for a small-scale electricity generation system. Energy and mass balance of the whole system will be done. The electricity generation efficiency will be assessed.
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| 9. |
- Pawel, Donaj, et al.
(författare)
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Reforming study of electric cable shredder from car residues into high-purity synthetic gas : Paper # (08-A-32-AWMA-IT3)
- 2008
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Ingår i: Air and Waste Management Association - 27th Annual International Conference on Thermal Treatment Technologies 2008. - 9781605603797 - 9781605603797 ; , s. 709-716
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Konferensbidrag (refereegranskat)abstract
- Car industry and also another producer consume spend huge amount of electric cables. After end of life equipment this is a source of nonferrous metals and electric cable shredders. This paper presents experiment study on high quality synthetic gas produce from plastic cables isolation shredders take advance of high temperature gasification. Experimental results of laboratory scale batch type gasification reactor are presented. Small amount of samples was inserted to process agent like mixture of oxygen (1% vol.) with nitrogen and just in to pure steam. Tests were repeated in different temperatures up to 1323K. Base on this experiments mass balance, composition and heating value of gas was calculate. Moreover tars composition was investigate. All the cases with gasification agents and different temperatures were repeated with different duration time and mass loss ratio were draw. High temperature of the process gives strong impact on hydrogen production and tar decomposition. Pure steam gasification significantly improves gas heating value and reduce tar amount in gas.
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| 10. |
- Ponzio, Anna, et al.
(författare)
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Combustion of coal in high temperature oxygen diluted and oxygen enriched conditions
- 2006
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Ingår i: A and WM, Annual International Conference on Incineration and Thermal Treatment Technologies, IT3. - 0923204849 - 9780923204846 ; , s. 202-216
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Konferensbidrag (refereegranskat)abstract
- In this investigation, coal pellets were combusted using a high temperature oxidizer (600-1000°C), both in oxygen diluted and oxygen enriched conditions, using a small scale batch reactor able to preheat the oxidizer to 1000°C. The combustion process and flame are described and mass, temperature and heating rate as function of time for different oxidizer compositions and temperature discussed. The results show that high temperature conditions gives the highest mass loss rates. The influence of oxygen concentration on mass loss rate is more evidenced for enriched conditions and/or lower oxidizer temperatures. Diluted conditions are associated with large flames while a typical flame downstream from the sample was almost absent for oxygen concentrations above 50%. Ignition time is highly dependent on oxygen concentration only when a 600°C oxidizer was used while almost independent when a 1000°C oxidizer was used.
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