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21.
Kung-Yuh Chiang Ming-Hui Lin Cheng-Han Lu Kuang-Li Chien Yun-His Lin 《International Journal of Green Energy》2015,12(10):1005-1011
This research investigates an enhanced removal rate of tar and trace pollutants (e.g. hydrogen chloride and hydrogen sulfide, H2S) in the gasification of rice straw, using an integrated in situ tar reduction and hot-gas cleaning technique. The gasification temperature was set at 900°C and equilibrium ratio (ER) was 0.30 in the gasifier. In the in situ tar reduction method, the catalyst, dolomite with an amended ratio of 0–15% was introduced to the gasifier. The integrated hot-gas cleaning system applied a multi-packed tower to remove the tar, sulfur and/or chlorine byproduct in syngas at 250°C. The packed materials composed of zeolite, calcined dolomite and activated carbon. The experimental results indicated that the tar concentration of syngas was approximately 20 g/kg. However, in catalytic gasification with 5% dolomite addition, the tar concentration reduced to 17 g/kg. The tar reduction efficiency was approximately 15% by an in situ dolomite addition. When applying the integrated hot-gas cleanup system, the tar was virtually eliminated. The total tar elimination rate was almost 100% and the cleaned syngas could be applied in other energy utilization equipment. On the other hand, the H2S and HCl concentration were 101 ppmv and 991 ppmv, respectively. After the integrated syngas cleaning system, the H2S and HCl were decreased to 7.9 ppmv and 410 ppmv with a removal efficiency of 92.1% and 58.6%, respectively. It can be concluded that combining the in situ method with the integrated syngas cleaning system can effectively reduce the amount of byproduct and enhance the syngas quality in the gasification of rice straw. 相似文献
22.
Yasuhiko Wada Takuma Okumoto Nariaki Wada 《Journal of Material Cycles and Waste Management》2008,10(2):173-187
Waste disposal systems conventionally exhibit many problems, such as difficulties in finding final disposal sites for incinerator
residues and the issue of how to recycle waste materials. Some new technologies have been developed to solve such problems,
including ash melting and gasification melting. Furthermore, to improve the power generation efficiency of waste treatment
facilities so that their energy is used more efficiently, combined stoker/gas turbine power generation (super waste power
generation) technology has been developed. Through examination of two cases in this study, environmental impacts and costs
were determined using lifecycle assessment (LCA) and lifecycle cost (LCC) methods in a model city. In case 1, a stoker furnace
was compared to a combined stoker/gas turbine system. In case 2, a stoker furnace plus ash melting system was compared to
a gasification melting system. The results demonstrate that the stoker furnace has a lower environmental impact than the combined
stoker/gas turbine system in case 1, and that the stoker plus ash melting system costs less than the gasification melting
system in case 2, but both systems had strong impacts on the environment. 相似文献
23.
This article describes the gasification of polyethylene–wood mixtures to form syngas (H2 and CO) with the aim of feedstock recycling via direct fermentation of syngas to ethanol. The aim was to determine the effects
of four process parameters on process properties that give insight into the efficiency of gasification in general, and particularly
into the optimum gasification conditions for the production of ethanol by fermentation of producer gas. Gasification experiments
(fluidized bed, 800°–950°C) were done under different conditions to optimize the composition of syngas suitable for fermentation
purposes. The data obtained were used for statistical analysis and modeling. In this way, the effect of each parameter on
the process properties was determined and the model was used to predict the optimum gasification conditions. The parameters
varied during the experiment were gasification temperature, equivalence ratio, the ratio of plastic to wood in the feed, and
the amount of steam added to the process. The response models obtained proved to be statistically significant in the experimental
domain. The optimum gasification conditions for maximization of carbon monoxide and hydrogen production were identified. The
conditions are: temperature 900°C, equivalence ratio 0.15, amount of plastic in the feed 0.11 g/g feed, and amount of steam
added 0.42 g/g feed. These optimum conditions are at the edge of the present experimental domain. The maximum combined CO
and H2 efficiency was 42%, and for the maximum yield of CO and H2 it is necessary to minimize the polyethylene content, minimize the added steam and the equivalence ratio, and maximize temperature. 相似文献
24.
Gasification and smelting system using oxygen blowing for plastic waste including polyvinyl chloride
Takaiku?YamamotoEmail author Hirotaka?Sato Yoshinori?Matsukura Yutaka?Ujisawa Hiroaki?Ishida Shuichi?Sasaki Yasuyuki?Hata 《Journal of Material Cycles and Waste Management》2004,6(1):6-12
A new type of waste gasification and smelting system using oxygen blowing based on high-temperature metallurgy, was developed by Sumitomo Metals, Japan. This system can steadily gasify and melt not only municipal waste, but also plastic waste and polyvinyl chloride (PVC) waste by using a top-blow oxygen lance together with sideways-blow oxygen lances. As a result of gasification in the high-temperature reducing atmosphere and rapid gas cooling, dioxin-free, high-calorie purified gas was produced. Ash components in the wastes were smelted in a high-temperature reducing atmosphere, and high-quality slag free of heavy metals was produced. Most of the chlorine in the wastes was converted into hydrogen chloride in the off gas. The hydrogen chloride can be recovered as hydrochloric acid or chlorine, which are recyclable to PVC manufacturing. 相似文献
25.
The process design of a 10–20 MWth Synthetic Natural Gas (SNG) production process from wood has been performed. Combining process modelling and process integration techniques, this study proceeds via the following stages:
- • thermodynamic modelling: mass, energy balances and simulation of the wood gasification, the methanation and the purification units;
- • process integration that identifies the energy saving opportunities and prepares a thermo-economic optimization.
26.
Wei Wu Katsuya Kawamoto Hidetoshi Kuramochi 《Journal of Material Cycles and Waste Management》2006,8(1):70-77
The purpose of this study was to establish a fuel process for an advanced power generation system in which hydrogen-rich synthesis
gas, as the fuel for the molten carbonate fuel cell (MCFC), can be extracted from biomass via gasification and reforming technologies.
Experiments on waste wood gasification were performed using a bench-scale gasification system. The main factors influencing
hydrogen generation in the noncatalytic process and in the catalytic process were investigated, and temperature was identified
as the most important factor. At 950°C, without employing a catalyst, hydrogen-rich synthesis gas containing about 54 vol%
hydrogen was extracted from feedstock with appropriately designed operation parameters for the steam/carbon ratio and the
equivalence ratio. However, by employing a commercial steam reforming catalyst in the reforming process, similar results were
obtained at 750°C. 相似文献
27.
Giovanni Cagnetta Kunlun Zhang Qiwu Zhang Jun Huang Gang Yu 《Frontiers of Environmental Science & Engineering》2019,13(1):11
28.
Sulc J Stojdl J Richter M Popelka J Svoboda K Smetana J Vacek J Skoblja S Buryan P 《Waste management (New York, N.Y.)》2012,32(4):692-700
A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kWth. The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950 °C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER = 0.71) led to substantial reduction of gas heating value (LHV = 3.15 MJ/Nm3), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950 °C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the second stage presented only few mass% of the inlet biomass stream. 相似文献
29.
From feathers to syngas - technologies and devices 总被引:1,自引:0,他引:1
The poultry waste produced by industrial slaughterhouses typically contains not only feathers, but also a mixture of animal entrails, nails, blood, beaks and whole carcasses. Economical utilisation of this mixture, varying strongly in composition and moisture content, is, in general, difficult. We demonstrate that this awkward material can be successfully used for gasification in a simple, fixed-bed gasifier. The method of gasification, which we developed, enables control of the gasification process and ensures its stability in the operational regime of a working poultry processing plant. The installation, which has been working in Poland for 2 years, utilises 2 tons of feathers per hour and produces syngas of stable composition and fairly high quality. The syngas is burnt in the combustion chamber adjacent to the gasifier. Heat is recuperated in a boiler producing 3.5 tons per hour of technological steam continuously used for the operation of the slaughterhouse. The whole process complies with the stringent emission standards. In the paper we present the end-use device for feather utilisation and describe the underlying gasification and syngas combustion processes. Key elements of the whole installation are briefly discussed. The environmental impacts of the installation are summarized. 相似文献
30.
The current article focuses on gasification as a primary disposal solution for cellulosic wastes derived from chicken farms, and the possibility to recover energy from this process. Wood shavings and chicken litter were characterized with a view to establishing their thermal parameters, compositional natures and calorific values. The main products obtained from the gasification of chicken litter, namely, producer gas, bio-oil and char, were also analysed in order to establish their potential as energy sources. The experimental protocol included bomb calorimetry, pyrolysis combustion flow calorimetry (PCFC), thermo-gravimetric analyses (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, elemental analyses, X-ray diffraction (XRD), mineral content analyses and gas chromatography. The mass and energy balances of the gasification unit were also estimated. The results obtained confirmed that gasification is a viable method of chicken litter disposal. In addition to this, it is also possible to recover some energy from the process. However, energy content in the gas-phase was relatively low. This might be due to the low energy efficiency (19.6%) of the gasification unit, which could be improved by changing the operation parameters. 相似文献