共查询到20条相似文献,搜索用时 31 毫秒
1.
Ho-Jun Song Jaehoon Lee Ankur Gaur Jong-Jin Park Jin-Won Park 《Journal of Material Cycles and Waste Management》2010,12(4):295-301
In this study, refuse plastic fuel (RPF) was copyrolyzed with low-quality coal and was gasified in the presence of a metal
catalyst and steam. Some metal catalysts, such as Ni, NiO, and Mg, and mixtures of these with base promoters such as Al2O3 and Fe2O3 were employed in the pyrolysis and gasification processes to convert the synthesis gas into more valuable fuel gas. The operating
temperatures for the pyrolysis and gasification were between 700° and 1000°C. The experimental parameters were the operating
temperature, catalyst type, basic promoter type, and steam injection amount. Solid fuel samples (5 g) were fed into a semibatch-type
quartz tube reactor when the reactor reached the designated temperature. The synthesis gas was analyzed by gas chromatography.
The use of low-quality coal as fuel in co-pyrolysis with RPF was explored. For the co-pyrolysis of RPF and low-quality coal,
the effectiveness of the catalysts for fuel gas production followed the order Mg > NiO > Ni. In catalytic gasification of
RPF, the addition of Al2O3 seemed to reduce the activity of the corresponding catalysts Ni and Mg. The maximum fuel gas yield (92.6%) was attained when
Mg/Fe2O3 was used in steam gasification at 1000°C. 相似文献
2.
Pyrolysis and steam gasification of woody biomass chip (WBC) obtained from construction and demolition wastes, refuse-derived fuel (RDF), and refuse paper and plastic fuel (RPF) were performed at various temperatures using a lab-scale instrument. The gas, liquid, and solid products were examined to determine their generation amounts, properties, and the carbon balance between raw material and products.The amount of product gas and its hydrogen concentration showed a considerable difference depending on pyrolysis and steam gasification at higher temperature. The reaction of steam and solid product, char, contributed to an increase in gas amount and hydrogen concentration. The amount of liquid products generated greatly depended on temperature rather than pyrolysis or steam gasification. The compositions of liquid product varied relying on raw materials used at 500 °C but the polycyclic aromatic hydrocarbons became the major compounds at 900 °C irrespective of the raw materials used. Almost fixed carbon (FC) of raw materials remained as solid products under pyrolysis condition whereas FC started to decompose at 700 °C under steam gasification condition.For WBC, both char utilization by pyrolysis at low temperature (500 °C) and syngas recovery by steam gasification at higher temperature (900 °C) might be practical options. From the results of carbon balance of RDF and RPF, it was confirmed that the carbon conversion to liquid products conspicuously increased as the amount of plastic increased in the raw material. To recover feedstock from RPF, pyrolysis for oil recovery at low temperature (500 °C) might be one of viable options. Steam gasification at 900 °C could be an option but the method of tar reforming (e.g. catalyst utilization) should be considered. 相似文献
3.
Tohru Kamo Kanji Takaoka Junichiro Otomo Hiroshi Takahashi 《Journal of Material Cycles and Waste Management》2006,8(2):109-115
Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of
various alkali compounds at 3.0 MPa and 560°C–660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen
and steam. Hydrogen and sodium carbonate were the main products, and methane and carbon dioxide were the minor products. Yields
of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds
on the gasification reaction was as follows: KOH > NaOH > Ca(OH)2 > Na2CO3. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However, the rate became
saturated at a molar ratio of NaOH/C greater than 2.0. 相似文献
4.
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
5.
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
6.
Lukáš Gašparovič Lukáš Šugár Ľudovít Jelemenský Jozef Markoš 《Journal of Material Cycles and Waste Management》2013,15(4):581-591
The work deals with catalytic gasification, pyrolysis and non-catalytic gasification of tar from an industrial dumping site. All experiments were carried out in a vertical stainless steel gasification reactor at 800 °C. Crushed calcined dolomite was used as the gasification catalyst. Parameters such as addition of water and air, and the influence of the catalyst in regard to the composition of the process gas were investigated. The catalytic gasification experiment in the steady state produced process gas with the composition: 56 % of H2, 9 % of CO, 11 % of CH4 and 12 % of CO2 (mol.%). Concentration of the C2 fraction was lower than 1 mol.%. Volume flow of air was later changed from 120 to 230 ml min?1 reducing the amount of hydrogen to 51 mol.% and that of methane to 10 mol.%. Process gas created in a non-catalytic gasification process contained 26–30 mol.% of methane, 13–15 mol.% of carbon monoxide and 15–17 mol.% of the C2 fraction and lower amounts of hydrogen (20 mol.%) and carbon dioxide (2–3 mol.%). The highest apparent conversion of tar was reached in the catalytic gasification processes. A higher rate of catalyst deactivation can be observed when water or air is not added. 相似文献
7.
Seong-Wan Kang Jong-In Dong Jong-Min Kim Woo-Chan Lee Won-Gu Hwang 《Journal of Material Cycles and Waste Management》2011,13(3):180-185
Various research has attempted to determine the proper treatment of sewage sludge, including thermal technologies. Efficient
thermal technologies have been focused on because of their energy saving/energy recovery. Gasification technology can be considered
one of these approaches. In this study, the characteristics of gasification reactions were investigated with the aim of finding
fundamental data for utilizing sewage sludge as an energy source. For the experiments on sewage sludge gasification reaction
characteristics, a laboratory-scale experimental apparatus was set up with a fluidizing bed reactor of 70-mm inner diameter
and 600-mm total height using an electric muffle furnace. The experimental materials were prepared from a sewage treatment
plant located in Seoul. The reaction temperature was varied from 630 to 860°C, and the equivalence ratio from 0.1 to 0.3.
The gas yields, compositions of product gas, and cold gas efficiencies of product gas were analyzed by GC/TCD and GC/FID installed
with a carboxen-1000 column. The experimental results indicated that 800°C, ER 0.2 was an optimum condition for sewage sludge
gasification. The maximum yield of product gas was about 44%. Producer gas from experiments was mainly composed of hydrogen,
carbon monoxide, carbon dioxide, and methane. The cold gas efficiency of sewage sludge gasification was about 68%. The H2/CO ratio and CO/CO2 ratio were about 1.1 and 1.4, respectively, in optimum reaction conditions. Gaseous pollutants such as SO2, HCl, NH3, H2S, and NO2 were also analyzed at various gasification/combustion conditions, and their gaseous products were compared, showing significantly
different oxidized product distributions. 相似文献
8.
Tohru Kamo Beili Wu Yuriko Egami Hajime Yasuda Hideki Nakagome 《Journal of Material Cycles and Waste Management》2011,13(1):50-55
Steam gasification in the presence of carbonate compounds is an effective method to recover useful materials from electronic
waste streams by converting plastics into gaseous products that can be used for energy production and avoiding the expensive
manual disassembly process. We investigated steam gasification of activated carbon in the presence of various mixtures of
lithium carbonate, sodium carbonate, and potassium carbonate. The activated carbon was almost completely converted into hydrogen
and carbon dioxide at 700°C under 0.1 MPa pressure in the presence of carbonate mixtures. Carbon dioxide was also derived
from partial decomposition of lithium carbonate. Steam gasification was accelerated in the presence of various carbonate mixtures
and at increasing steam partial pressures. These experimental results show that fluidity of carbonates, the potassium content
of the carbonate, and the steam partial pressure are important factors in accelerating steam gasification. 相似文献
9.
The process of producing synthetic gas from waste plastics by steam reforming was investigated. To evaluate this process,
the steam reforming of the oils derived from low-density polyethylene and polystyrene were carried out using a laboratory-scale
fluidized bed of Ni-Al2O3 catalysts. The performance of gasification in terms of carbon conversion, gas yield, and gas compositions was examined. Although
oils derived from plastics contain many kinds of heavy hydrocarbons and aromatics, they were well gasified at temperatures
above 1023 K with a steam/carbon ratio of 3.5 and a weight hourly space velocity of 1 h−1. The hydrogen content of the product gas was very high at approximately 72 vol% for polyethylene-derived oil and 68 vol%
for polystyrene-derived oil. These compositions agreed well with the values calculated from chemical equilibrium. 相似文献
10.
Jong Jin Park Ho-Jun Song Jin-Won Park 《Journal of Material Cycles and Waste Management》2013,15(1):37-41
The purpose of this study was to investigate the possibility of light gases produced from polypropylene, specifically hydrogen. In particular, we examined the effect of operating conditions on gaseous product and compositions in the catalytic cracking of polypropylene. We also characterized the gaseous product generated from polypropylene cracking. The feedstock (2.0 g) mixed with NiO/SiO2–Al2O3 (Si–Al) was used, under non-isothermal conditions at low temperature range between 380 and 500 °C. Argon gas was used to carry the pyrolyzed gas, and the gas collected in a tedlar bag was analyzed for its behavior. We observed the behavior of major gases (H2, CH4, C2H4 and C3H6, etc.) according to reaction time and temperature. Finally, the effect of reaction conditions on evolved gases from catalytic cracking of polypropylene was analyzed. 相似文献
11.
Kyung-Won Lee Woo Chan Lee Hyuk Jun Lee Jong In Dong 《Journal of Material Cycles and Waste Management》2014,16(4):642-649
The gas products from gasification processes have been considered to have some limitations in gas composition and heating value from the previous studies. Gasification characteristics of sewage sludge and wood mixture were investigated using different mixing ratios with the purpose of better quality of gas product suitable for energy/power generation. The gasification experiment was performed by an indirectly heated fluidized bed reactor. As reaction temperature increased from 600 to 900 °C, the yield of gas product increased with higher generation of CO, H2 and CH4 by more activated gas conversion reactions. As the equivalence ratio increased from 0.2 to 0.4, composition ratio of CO2 increased while CO, CH4, H2 decreased as expected. Several operating variables including mixing ratio of wood with dried sludge were also tested. From this initial stage of experiment, optimal operating conditions for the bubbling fluidized bed gasifier, could be considered 900 °C in temperature; 0.2 in equivalence ratio and 40 % in wood mixing ratio within test variables range. These results will be more thoroughly investigated for the application to the larger scale pilot system. 相似文献
12.
Sabrina Portofino Antonio Donatelli Pierpaolo Iovane Carolina Innella Rocco Civita Maria Martino Domenico Antonio Matera Antonio Russo Giacinto Cornacchia Sergio Galvagno 《Waste management (New York, N.Y.)》2013,33(3):672-678
An experimental survey of waste tyre gasification with steam as oxidizing agent has been conducted in a continuous bench scale reactor, with the aim of studying the influence of the process temperature on the yield and the composition of the products; the tests have been performed at three different temperatures, in the range of 850–1000 °C, holding all the other operational parameters (pressure, carrier gas flow, solid residence time). The experimental results show that the process seems promising in view of obtaining a good quality syngas, indicating that a higher temperature results in a higher syngas production (86 wt%) and a lower char yield, due to an enhancement of the solid–gas phase reactions with the temperature. Higher temperatures clearly result in higher hydrogen concentrations: the hydrogen content rapidly increases, attaining values higher than 65% v/v, while methane and ethylene gradually decrease over the range of the temperatures; carbon monoxide and dioxide instead, after an initial increase, show a nearly constant concentration at 1000 °C. Furthermore, in regards to the elemental composition of the synthesis gas, as the temperature increases, the carbon content continuously decreases, while the oxygen content increases; the hydrogen, being the main component of the gas fraction and having a small atomic weight, is responsible for the progressive reduction of the gas density at higher temperature. 相似文献
13.
Leguan Zhang Bo Xiao Zhiquan Hu Shiming Liu Gong Cheng Piwen He Lei Sun 《Waste management (New York, N.Y.)》2014,34(1):180-184
Pyrolysis of sewage sludge was studied in a free-fall reactor at 1000–1400 °C. The results showed that the volatile matter in the sludge could be completely released to gaseous product at 1300 °C. The high temperature was in favor of H2 and CO in the produced gas. However, the low heating value (LHV) of the gas decreased from 15.68 MJ/N m3 to 9.10 MJ/N m3 with temperature increasing from 1000 °C to 1400 °C. The obtained residual solid was characterized by high ash content. The energy balance indicated that the most heating value in the sludge was in the gaseous product. 相似文献
14.
This study conducted gasification and catalytic reforming experiments with the expectation of obtaining new advantages on energy recovery and aimed for the development of an effective catalyst. Initially, the use of thermal gasification technology for waste treatment in line with waste-to-energy strategies was reviewed. Technological systems which have gasification were classified and their current status was discussed. Then, the results of gasification and reforming experiments showed that product gas with 50 % H2 or more was obtained using a Ni catalyst on a mesoporous silica–based SBA-15 support (NiO/SBA-15), which we newly developed. Experiments using wood feedstock revealed that H2 production by the catalyst was better when the NiO content was 20 % (W/W) or more than when another catalyst or the Ni catalyst with a lower Ni loading was used. Tar formation as a by-product was also well controlled by the catalyst, and use of a catalyst with 40 % NiO reduced the tar concentration to less than 0.2 g/\( {\text{m}}^{3}_{\text{N}} \). Experiments using a mixed feedstock of wood and RPF resulted in an increase in hydrocarbon concentration because of insufficient reforming. This finding suggests that future work is required to find a better solution to wood and RPF co-gasification. 相似文献
15.
Won-Seok Yang Jang-Soo Lee Se-Won Park Jae-Jun Kang Tanvir Alam Yong-Chil Seo 《Journal of Material Cycles and Waste Management》2016,18(3):509-516
To recycle polyurethane foam waste generated from electric appliance recycling centers for use as fuel in a gasification process, polyurethane solid refuse fuel fabricated as pellets was analyzed for the characteristics of elemental composition, proximate analysis, heating value, and thermo-gravimetric testing. It has a high heating value of 29.06 MJ/kg with a high content of combustibles, which could be feasibly used in any thermal process. However, the nitrogen content, of up to 7 %, was comparably higher than for other fuels such as coal, biomass, and refuse-derived fuel, and may result in the emission of nitrogenous pollutant gases of HCN and NH3. By conducting gasification experiments on polyurethane solid refuse fuel in a fixed-bed reactor, a syngas with a heating value of 9.76 kJ/m3 and high content of both H2 and CO were produced with good gasification efficiency; carbon conversion 54 %, and cold gas efficiency 60 %. The nitrogenous pollutant gases in syngas were measured at the concentrations of 160 ppm hydrogen cyanide and 40 ppm ammonia, which may have to be reduced using proper cleaning technologies prior to the commercialization of gasification technology for polyurethane waste. 相似文献
16.
Galvagno S Casciaro G Casu S Martino M Mingazzini C Russo A Portofino S 《Waste management (New York, N.Y.)》2009,29(2):678-689
In the field of waste management, thermal disposal is a treatment option able to recover resources from "end of life" products. Pyrolysis and gasification are emerging thermal treatments that work under less drastic conditions in comparison with classic direct combustion, providing for reduced gaseous emissions of heavy metals. Moreover, they allow better recovery efficiency since the process by-products can be used as fuels (gas, oils), for both conventional (classic engines and heaters) and high efficiency apparatus (gas turbines and fuel cells), or alternatively as chemical sources or as raw materials for other processes. This paper presents a comparative study of a steam gasification process applied to three different waste types (refuse-derived fuel, poplar wood and scrap tyres), with the aim of comparing the corresponding yields and product compositions and exploring the most valuable uses of the by-products. 相似文献
17.
Due to the high-temperature boiler corrosion induced by chloride-rich fly ash deposits, steam generation in today’s Waste-to-Energy (WtE) plants is typically designed only for 40 bar/400 °C as an economic compromise between acceptable corrosion rate and maximum power generation. The high-corrosive metal chlorides in the fly ash can react with SO2 forming low-corrosive sulfates. The sulfation efficiency is enhanced by high SO2 levels and sufficient residence time of the flue gas at high-temperatures (700–900 °C). The fly ash sulfation was tested in full scale in a Swedish WtE plant by applying the economic sulfur recirculation method. Probes of several alloys (16Mo3, Inconel 625, Sanicro 28) were exposed for 1000 h at controlled material temperatures in the superheater position, at normal and during sulfating operation respectively. Analyses of the fly ash showed that the molar Cl/S was decreased to values well below 1 and the corresponding corrosion rates of the individual material samples were less than half when sulfur recirculation was in operation. These positive findings demonstrate that the sulfur recirculation process has high potential for low-corrosive high-temperature steam generation (T ≈ 500 °C) and improved electricity production. Further steam superheating can be realized by staged superheating using small amounts of secondary fuel. 相似文献
18.
Steam gasification of two different refuse derived fuels (RDFs), differing slightly in composition as well as thermal stability, was carried out in a fixed-bed reactor at atmospheric pressure. The proximate and ultimate analyses reveal that carbon and hydrogen are the major components in RDFs. The thermal analysis indicates the presence of cellulose and plastic based materials in RDFs. H2 and CO are found to be the major products, along with CO2 and hydrocarbons resulting from gasification of RDFs. The effect of gasification temperature on H2 and CO selectivities was studied, and the optimum temperature for better H2 and CO selectivity was determined to be 725 degrees C. The calorific value of product gas produced at lower gasification temperature is significantly higher than that of gas produced at higher process temperature. Also, the composition of RDF plays an important role in distribution of products gas. The RDF with more C and H content is found to produce more amounts of CO and H2 under similar experimental conditions. The steam/waste ratio showed a notable effect on the selectivity of syngas as well as calorific value of the resulting product gas. The flow rate of carrier gas did not show any significant effect on products yield or their distribution. 相似文献
19.
Shangzhong Zhang Kunio Yoshikawa Hideki Nakagome Tohru Kamo 《Journal of Material Cycles and Waste Management》2012,14(4):294-300
To recover useful metals from end-of-life electronic devices and to convert plastic components from these devices into clean fuel gas, steam gasification of epoxy board samples was carried out at 600–700?°C and 0.1?MPa pressure in the presence of a ternary eutectic carbonate (lithium carbonate, sodium carbonate, and potassium carbonate). Hydrogen and carbon dioxide were the main products, and methane and carbon monoxide were detected as minor products. The gasification proceeded in two steps: an initial rapid pyrolysis followed by secondary steam gasification of char produced from the pyrolysis. The ternary eutectic carbonate accelerated not only the latter steam gasification but also the initial rapid pyrolysis. The activation energy for the steam gasification of epoxy board samples in the presence of the carbonate was 122?kJ/mol. 相似文献
20.
Sven Andersson Evalena W. Blomqvist Linda Bäfver Frida Jones Kent Davidsson Jan Froitzheim Martin Karlsson Erik Larsson Jesper Liske 《Waste management (New York, N.Y.)》2014,34(1):67-78
Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop.The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion.In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60–90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion. 相似文献