Abstract: The gas production process in underground coal gasification is closely related to the temperature distribution in gasification oven and seepage conditions. A mathematical model on underground gasificaton in steep coal seam is established, according to its storage conditions and the feafures of gas production process. The paper also introduces the methods of how to determine the main model parameters, and gets the model values by means of the control volume method, and gives an analysis of the calculation results on the basis of model experiment. From the distribution of temperature field, the calculation values are slightly higher than the real measurement ones. The relative differentiations of all measuring points are by and large within 10%. According to the simulated calculation results, with the increase of the length of the gasification channel, the heating value of the gas increases. However, after the reduction zone, it increases with a smaller margin. The temperature field exerts noticeable effects on the heating value of the gas. Due to the effect of temperature, in high temperature zone, the change gradient of the measured values of the concentration field of the gas compositions is larger than that of calculated ones. On the whole the simulated values are identical with the test ones,which manifests the numerical simulation on the temperature field and concentration field in steep seam is right.
Abstract: The particle model was employed to study the coal devolatilization, the release of volatile fuel-nitrogen, formation of HCN and the subsequent conversion to NO during the devolatilization. The finite volume numerical scheme was used to solve the equations of mass, chemical species, momentum and heat transfer conservation about the coal particle. The two competing reactions model was used to describe the devolatilization process, the results from the numerical simulations were compared and also verified with the experimental data. The simulating results show that the furnace temperature, particle diameter and the environmental oxygen concentration have influences on the release of volatile fuel nitrogen and the subsequent conversion to NO.
Abstract: The effect of temperature and steam partial pressure on gasification characteristics was investigated using thermobanlace. The results showed that the gasification reactivity of petroleum cokes is high. The reaction rate, R＝dx/dt, has a maximum value when carbon conversion is about 0.2 as the reaction proceeds. The carbon conversion corresponding to the maximum reaction rate is independent of temperature and steam partial pressure. And the specific gasification rate, M=dx/dt/(1-x), increases continuously during the gasification of petroleum cokes. It has a linear relationship with carbon conversion during the carbon conversion from xmax to 0.8. The specific surface area increases with increasing carbon conversion. The specific gasification rate has a good relativity with the effective specific surface area occupied by pores larger than 0.6 nm.
Abstract: The fusion point of ash from No.12 Mine was investigated after CaO and Fe2O3 were respectively added as fusing agent. At the same time, the gasification activity of chars added different quantity of fusing agent was examined at 1 300 ℃～1 550 ℃. The results showed that the appropriate addition should be 3%～7% for CaO and 5%～10% for Fe2O3 respectively. There was close relationship between the influence of quantity of additives on gasification activity of char and the gasification temperature. At relatively lower temperature, the gasification activity of char increased with increasing quantity of fusing agent. However, the influence became little with increasing temperature. When temperature was up to 1 550 ℃, the influence of fusing agent almost vanished because of the fusion and agglomeration of fusing agent at higher temperature.
Abstract: Minerals are important composition in coal and coal-ashes. In this study, the coal samples were collected from seam 6 in Huaibei coal field. The minerals and trace elements in the coal and the coal-ash were investigated by INNA, chemical method, X-ray diffraction and scanning electron microscopy. On the basis of the methods, the main species and forming factor of minerals in coal and coal ashes are analyzed. According to the result, the coal ashes are the residues derived from the inorganic and organic matter during coal combustion and the ash is an important and routinely determined characteristics of quality of coal. Coal ashes are mainly consisted of kaolinite, quartz, calcite, pyrite and many trace elements in the studied samples. The concentrations of trace elements and the species of the minerals were changed and the new steady species of minerals were formed during coal combustion.
Abstract: This paper introduces an economical and simple experimental method to measure the onset sintering temperature of mixed coal ash. Under the pressure calculated from the formula , the ash with mass 3 g～5 g is compressed into ash bar in an Al2O3 tube with 8 mm～10 mm inner diameter. The pressure drop along with the ash bar versus temperature raised at a rate of 2 ℃/min～4 ℃/min temperature-increasing rate is measured with air flow rate at 10mL/min～40 mL/min. The onset sintering temperature of mixed coal ash is the temperature at which the pressure drop reaches maximum. The onset sintering temperatures of IHI CFB boiler ash and Qin Huangdao CFB boiler ash were measured. The onset sintering temperature of IHI CFB boiler ash is 900 ℃±10 ℃, which can partially explain the phenomena of the IHI CFB boiler can not run smoothly due to the sintering of ash and slag.
Abstract: The effects of Ammonium Molybdate catalyst were studied by using resonance agitation reactor during coprocessing Yangcun bituminous coal and Shengli residue with Tetralin as solvent under the hydrogen pressure of 7.0 MPa (ambient temperature). The results show that the catalyst not only increase coal conversion, but also promote convertion of preasphaltene benzene soluble products at low temperature (390 ℃). Coal conversion, Benzene soluble product yield and preasphaltene yield is lower with catalyst than without catalyst at high temperature (480℃). It means the catalyst can not resist the polycondension in the reaction system having hydrogen donor solvent at high temperature (480 ℃). Polycondension reaction increases rapidly with the increasing of the reaction temperature and reaction time at high temperature.
Abstract: Straw pyrolysis in supercritical water was studied using a high-pressure batch autoclave. The effects of temperature, pressure and reaction time on the distribution of pyrolysis products were examined. Results indicate that the yield of gas and oil increased with increasing temperature at first, and then oil yield decreased. The highest oil yield 28.57% was reached from 380 ℃ to 410 ℃. The yield of gas and oil increased with increasing pressure while the yield of residue decreased notably. When pressure is higher than 31.5 MPa, the yield of oil did not vary with pressure. The yield of gas increased with reaction time, and the yield of oil increased at first, and then decreased.
Abstract: To find out the essence of the coke deactivation and probe into the way of elimination of the coke deactivation over zeolite catalysts in methane non-oxidative aromatization, the coke soluble or insoluble in CH2Cl2 was separated. Its composition and property were characterized by MS and IR methods. It was found that the soluble coke mainly consists of non-aromatic hydrocarbons. Its composition did not change with the reaction time, reaction temperature and acidity of the catalyst. The souble coke which was the precursor of the insoluble coke did not affect the activity of the catalysts. The souble coke formed mainly in the pores of zeolite catalysts. The insoluble coke consisted of the condensed-aromatics type hydrocarbon. Its composition changed with the reaction time, reaction temperature and acidity of the catalyst. The insoluble coke was divided into two types: burning mainly at 798 K and 843 K respectively. The insoluble coke of the two types with different H/C might be the main reason for the deactivation of catalysts.
Abstract: ZSM-5 zeolites synthesized with varying the concentration of n-butylamine in gel were studied. The samples were characterized by XRD, SEM and BET surface area measurements. Under synthetic condition of this study, the range of optimum concentration of n-NBA(NBA/SiO2) is from 0.67 to 0.22, the relative crystallinity of ZSM-5 zeolites synthesized is over 90%. As template concentration decreased, particle size and BET surface area of ZSM-5 zeolites decreased. The acidity was measured by temperature-programmed desorption (TPD) of ammonia. It was found that the number of strong acid sites decreased almost linearly with the concentration of template. Propene oligomerization reaction was carried out over the samples to evaluate the catalytic properties of ZSM-5 zeolites. The template concentration affected significantly on catalytic activities of the ZSM-5 zeolites. ZSM-5 zeolites synthesized with varying the concentration of n-butylamine form 0.67 to 0.22 in gel showed better catalytic activities and stability.
Abstract: A copper based catalyst has been used to synthesize of 1,4-cyclohexanedimethanol, which is an important intermediate in the production of modified polyester, by the hydrogenation of dimethyl 1,4-cyclohexanedicarboxylate under low pressure. The influences of temperature and pressure on the reactivity were discussed. The life test of the catalyst has been carried out for 200h. The result showed that the conversion of 1,4-cyclohexanedicarboxylate and selectivity to 1,4-cyclohexanedimethanol were higher than 95% and 98% respectively at 200 ℃, 3.0 Mpa. XRD spectra showed that copper is main active center of the catalyst.
Abstract: α-FeOOH nanoparticles were prepared using homogeneous precipitation and ammonia titration methods. The catalytic activity of the catalysts using α-FeOOH nanoparticle as active ingredient for COS hydrolysis were tested by a microreactor-chromatography assessing apparatus at the atmospheric pressure in the temperature range from 25 ℃～60 ℃ with gas hourly space velocity 10 000 h－1. The performance of the catalysts for H2S removal was investigated by means of thermal gravimetric method. The results show that the nanoparticle-based catalyst is highly active for COS hydrolysis at low temperature at high space velocity. Conversion of COS can attain 100% by use of series Ⅰ and Ⅱ catalysts at 60 ℃ and 40 ℃～45 ℃ respectively. The highest saturated sulfur capacity for H2S can reach 21.72% at 60 ℃. Further, it is also observed that the surface energy distribution on the catalysts is heterogeneous and a compensation effect exists.
Abstract: Samples (F-β and W-β) of zeolite-β synthesized by different templates were characterized by XRD, TPD and pore structure analysis. The differences of the zeolite-βsynthesized by two templates have been investigated through the activity evaluation of benzene alkylation reaction and the experiment of accelerated-aging. Coke composition on the deactivated catalysts used in industrial process and accelerated-aging experiment process was analyzed by MS-GC. The result shows that the two processes are similar in deactivation process of catalysts. Main coke materials are multi-aromatic hydrocarbons, which are deepening products of diisoproplbenzene alkylation. They can not diffuse from the pore of the zeolite easily, and block the pore path, and occupy the activity sites. Thus it makes the catalyst deactivated. Steric constraints during the formation of coke molecules are more pronounced in the relatively narrow cages than in the large cages. Because difference of pore distribution between F-βand W-βsamples, F-βsample has more the narrow cages (or more micropore) than W-βsample, and it has stronger steric constraint during deepening alkylation of disoproplbenzene than W-βsample, and lower coke is formatted on F-βsample. This reason results in better stability of the F-βsample. The pore structure data show that rational distribution of micropore in zeolite-βis very important to restrain producing of the coking materials. Different distribution of pore on zeolite-βis the main reason that makes F-βand W-βsamples have differences in the activity evaluation of alkylation reaction and stability of the accelerated-aging experiment.
Abstract: This paper presents the influence of the modified matrices of RFCC catalysts on the acidity and activity. The result shows that the surface area, pore volume and acidity of kaolin clay are all increased when it is baked and modified with acid. It also shows that when aluminum oxide is modified with phosphorus, its acid site is increased but acid strength is weakened. When these modified materials are used as the matrices of the olefin-reduce residual oil cracking catalysts, the activity for cracking and hydrogen-transfer as well as isomerization raise and the coke yield reduces.
Abstract: The NiO-SiO2 NiO-Al2O3 and NiO-Al2O3-SiO2 aerogel catalysts were prepared by sol-gel method. The silicon and aluminum in the catalysts came from n-ethyl silicate and Al(NO3) 3, respectively- Ni(NO3) 2 was used as the Ni precursor. The results showed that the conversion of maleic anhydride over the three catalysts are all higher than 99%, while the selectivity differs from each other different. The NiO-SiO2 catalyst gave 80.1% selectivity toγ-butyrolactone, while the NiO-Al2O3 catalyst had as high as 99% selectivity to succinic anhydride. As for the NiO-Al2O3-SiO2 catalyst, 74.5% to succinic anhydride and 25.5% toγ-butyrolactone were obtained respectively. The characterizations from the XRD and TPR showed that there are significant differences for those three catalysts, such as crystal forms, NiO dispersion, and the interactions between NiO and supports in the catalysts, which may result in the different catalytic performance in selective hydrogenation of maleic anhydride.
Abstract: A kind of carbonaceous nanometer pore adsorbent was produced from petroleum coke by a composite activation process. The pore width of the adsorbent among 1 nm～2 nm is over 90%. Under the condition of 25 ℃，3.5 MPa，the volume and mass adsorption of methane on the adsorbent are over 120 V/V and 14.0% respectively. Adsorption isotherm shows that the adsorption type belongs to theⅠadsorption, and in according with micropore filling theory; Adsorption isobar shows that low temperature favors the adsorption; the water contained in the adsorbents is harmful to the increase of the adsorption capacity.
Abstract: Bubble-point vapor pressures along with the coefficients of Antoine equation correlation were reported for 22 hydrocarbon fuel fractions with different true boiling temperature ranges to investigate the relationship of vapor-liquid phase equilibrium constants between wide and narrow fuel fractions. The fuel samples were originated from crude oils with the initial atmospheric boiling temperature from 348.15 K to 623.15 K. The vapor pressures at the range from about 8 kPa to 101.3 kPa were measured by using a specially designed inclined ebulliometer with a pump-like stirrer on the basis of the principle of quasi-static method. On the basis of a wide fuel fraction assumed to be composed of several pseudo components (narrow fuel fractions with the boiling temperature range of 25 K), the vapor-liquid phase equilibrium constants of different pseudo components at different bubble-point conditions were calculated. The VLE constants were also correlated with the boiling temperatures of the pseudo components, the phase equilibrium temperature and pressure. A generalized equation was obtained with an overall absolute average deviation of 4.5% from the experimental values tested by 180 datum points at the pressure range from 8 kPa to 101.3 kPa and the normal boiling temperature range of fuels from 348.15 K to 623.15 K, which can give reasonably satisfactory results in engineering calculation.
Abstract: Effects of contents of Na, Pt and Zr, and preparation of Pt-ZrO2/HM catalyst on n-pentane isomerization reaction were investigated in a continuous microreactor-chromatographic unit. A mathematical orthogonal experimental method was used to obtain an optimum reaction conditions: t=275 ℃, p=1.5 MPa, WHSV=1.25 h－1, H2/Ｃ50=2.0 (mole ratio). At the optimum conditions, Pt-ZrO2/HM catalyst achieved that n-pentane conversion is 69.88w%, isopentane yield is 67.68w%, isopentane selectivity is 96.85w%, yield of liquid product is 97.80w%.
Abstract: Precipitation of n-alkanes in diesel affects cold flow property. With XRD pattern, shape of crystals is able to be studied. But XRD pattern has not been applied to investigation of precipitation of crystals of n-alkanes appearing in diesel. In this paper, XRD pattern of a series of diesel flow improver(DFI), wax and mixture of wax and DFI are analyzed. The relationship between character of XRD pattern and performance of DFI is studied. When sharp peak between 10°～30° is little, shape of peak is ordered and curve of peak is smooth, performance of DFI is better. XRD pattern of the mixture of wax and DFI shows noncrystalline structure has changed. Hence it might be considered crystallization procedure of wax be affected by DFI. This work is also helpful to the full understanding of the mechanism of DFI.
Abstract: Hydrogen production by catalytic steam reforming of methanol over a series of coprecipitated Cu/ZnO/Al2O3 catalysts under atmospheric pressure in a microreactor has been studied. Effects of catalyst composition, reaction temperature and activation conditions on the catalytic activity have been investigated. Crystal phases of catalysts were analyzed by XRD. The results showed that Cu/ZnO/Al2O3 catalysts displayed high activity and selectivity for hydrogen and stability. The optimized molar ratio is Cu/Zn=1.0, a maximum methanol conversion of 99.4mol%, hydrogen selectivity of 99.9 mol% and CO molar fraction of 0.007% were obtained in the steam reforming reaction with the catalyst containing 45 mol% copper. XRD results showed that the diffraction peaks of CuO in the catalyst were clearly lower and broaden. It indicated that high dispersion of small copper crystallites on the catalyst surface was formed under the calcination conditions. It is suggested that the good performance of Cu/ZnO/Al2O3 catalysts partly resulted from well dispersed copper.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
