Abstract: Honeycomb cordierite based CuO/Al2O3 catalyst was studied for simultaneous SO2 and NO removal from flue gas. It is found that the addition of sodium in the catalyst can improve SO2 removal activity. However, the sodium addition will slightly decrease NO removal activity due to the increased NH3 oxidation. With increasing the reaction temperature from 350℃ to 450℃, the SO2 removal activity increases, while the NO removal activity decreases due to the increased NH3 oxidation. Space velocity shows a slight effect on NO removal in the range of 1450h－1～3600h－1, but a strong effect on SO2 removal activity. A catalyst composition, 6.0 % copper and 2.0 % sodium, was found to be optimal for simultaneous SO2 and NO removal. The suitable reaction temperature and space velocity are about 400 ℃ and 2 300 h－1 or below, respectively.
Abstract: The step-response transient kinetics techniques have been used for the exploration of the carbon gasification mechanism with the catalysis of metal compounds. According to the experimental results the reaction mechanism of gasification is proposed: firstly, the catalyst releases an oxygen atom from its rich-oxygen site to combine with a carbon atom and create a CO, then the CO molecule desorbs from the catalyst surface; next, the catalyst absorbs a CO2 molecule; and finally on the catalyst surface another CO molecule is created and the original rich-oxygen site gets an oxygen atom. On the basis of gasification process the material balance equations were built, which were solved by using numerrical integral methods and the reaction rate constants for four steps were obtained: they are 0.0703mol·g-1·min-1·kPa-1, 0.0959mol·g-1·min-1·kPa-1, 0.00539 mol·g-1·min-1 and 0.0321 mol·g-1·min-1·kPa-1 respectively. It can be concluded that the absorption of CO2 onto the catalyst is the control step of gasification process.
Abstract: The experiments were carried out to try to remove the inorganic sulfur and organic sulfur in the semi-coke at different gaseous mixtures and temperatures. The influence of recycling coke oven gas on the coke oven temperature was analyzed and the distribution of recycling coke oven gas in the carbonization chamber was simulated. The result shows that increasing the hydrogen content does favor to remove both inorganic sulfur and organic sulfur. However, rising the temperature does not always benefit the desulfurization. It would have little influence on the coke oven temperature if the coke oven gas is preheated before recycle. The optimal time to recycle the coke oven gas is that the pore distribution in the coke is becoming homogenous.
Abstract: Using thermal synthesis analyzer experimental research on the combustion characteristic of Huadian oil shale and Heshan coal mixture was studied. The effect of different Ca/S ratio on the combustion characteristic of the mixture was analyzed using the Thermal Gravity (TG) and Differential Thermal Gravity (DTG) curves. The kinetic parameters of combustion were obtained with Freeman-Carroll method. The results showed that the combustion characteristic of Heshan coal with small amount of oil shale added was improved. The initial temperature of pyrolysis of Heshan coal was decreased and the ignition temperature was lowered. About 20% of oil shale added in Heshan coal is feasible for desulfurization of the mixture during combustion.
Abstract: Three macerals, liptinite, vitrinite and inertinite separated from Pingshuo coal were used in this study. The formation of HCN during macerals pyrolysis was investigated using a quartz tube reactor at 600℃～900℃. Both the programmed heating and fast heating pyrolysis have been studied. It was found that the yield of HCN increased with pyrolysis temperature for all three macerals. The yield of HCN during vitrinite pyrolysis was the biggest among the three below 800℃, and that of liptinite was the highest at 900℃. The yields of HCN depended not only on their volatile content but also on the nitrogen functional groups in different macerals. More pyrrole-type nitrogen could form more HCN at lower temperature. The yield of HCN increased with increasing heating rate. Comparing the HCN yield at different period during pyrolysis, it could be found that most of HCN was released at the feeding period. The synergistic effect for the formation of HCN existed in the pyrolysis of acid-washed parent coal.
Abstract: The molecular modeling of Shenmu coal macerals has been studied and the energy compositions, bond length and bond dissociation energy (BDE) of different types of bonds in the vitrinite and inertinite have been compared by molecular mechanics and semi-empirical calculation method of quantum chemistry. The results show that the torsion energy and van der Waals interaction energy are the main types of energy and the substitution group has a great effect on the total energy of molecular. The aliphatic substitution would lead to the increase of total energy, while the aromatic substitution would lead to the decrease of total energy. The calculated results of bond length show that the bond length of aliphatic C—C is longer than that of aromatic C—C, which indicates that the rupture of aliphatic C—C is easier than that of aromatic C—C on heating. The calculation of BDE shows that the Car—Cal bond has a higher BDE than Cal—Cal, and Car—O bond has a higher BDE than Cal—O bond. And the higher BDE and more aromatic C—C in inertinite structural model than in vitrinite structural model maybe explain the fact that the inertinite has a higher thermal stability than vitrinite.
Abstract: A kinetic coal gasification model combining chemical equilibrium was established to evaluate various coal gasification schemes in a fluidized bed. Heterogeneous and homogeneous reactions occurred in coal pyrolysis and gasification processes were considered in this model. Model calculation results are in good agreement with the reported measurement data. The sum of squares of percentage deviation for gas composition calculation is about 10%, which implies that the established model can be used to predict the effects of various gasification schemes on process parameters, gas composition and gasification efficiency in fluidized bed coal gasification.
Abstract: A series of calculations were carried out to explore the effects of various gasification schemes on the performance of fluidized bed coal gasification using the mathematical model previously established by the authors. The gasification performances for five schemes including air, air/H2O, air/CO2, O2/H2O and O2/CO2 blown were studied. The main results show that the better gasification efficiency and higher syngas quality can be obtained from the schemes of air/H2O and O2/H2O. Furthermore, the O2/H2O scheme are more predominant than air/H2O scheme in syngas composition, gasification efficiency and thermal efficiency.
Abstract: The hydrogen-rich syngas produced by air-steam gasification of pine sawdust at 800 ℃ was used for direct dimethyl ether (DME) synthesis. The raw syngas contained large amount of CO2. The stoichiometric adjustment can be accomplished by CH4-CO2 dry reforming reaction with addition of CH4 under the condition of 700 ℃，0.1 MPa. The H2/CO ratio could be adjusted from 1.5 to 2.0. The content of CO2 and CH4 in the exit gas from the reforming reactor was below 3 mol%. The optimized CH4 addition rate was CH4/CO2=1. The results of DME synthesis from biomass syngas under the condition of 260 ℃,4 MPa,12 000 h－1 showed that biomass carbon conversion was above 70% and the selectivity to dimethyl ether in the synthesis reaction was 69.6%.
Abstract: The composition and pore-characterization of char from pyrolysis of used tires were determined in this paper. Three oxidizing agents were used for the activation of carbonized char, including steam, CO2 and 2％ O2 in nitrogen. Char-activation with CO2 was conducted primarily. The activated char can get a great surface area, which can be used to handle organic elding and textile industry waste. The result shows that the content of ashes and sulfurs in the pyrolysis char is pretty high and there is a maximum pore volume at the pore radius of about 25 nm. At the condition of same activation time and gas flow rate, the higher the temperature is, the larger the burn-off rate and the surface area are. Also, at the condition of the same temperature and gas flow rate, the longer activated time is, the larger burn-off rate and BET are. For all activation experiments, the higher burn-off rate would result in larger surface area. The activation effect with steam and CO2 is better, and followed by that with 2％ O2 in nitrogen. By the comparison of activated char and commercial activated carbon, the former has a profound pore-characterization and it has a potential to substitute commercial activated carbons for the macromolecular absorption.
Abstract: Chloride emission character of sawdust incineration was studied using a fixed bed reactor. The effects of combustion temperature, retention time, combustion atmosphere, content of steam on reaction rate were investigated. From experimental results, the kinetic equation was established. The results also demonstrate that Cl-HCl conversion rate increases as combustion temperature rises during combustion. With the increment of retention time, two peaks exist in the emission curve, which suggest that more than two kinds of chlorine exist in the sawdust. There is little effect of oxidative atmosphere on chloride emission. When the reductive atmosphere changes from weak to strong, Cl-HCl conversion rate decreases rapidly. And the existence of steam can accelerate the release of chlorine. The reaction order of sawdust combustion is zero.
Abstract: Scrap tyres were pyrolyzed in a pilot-scale rotary kiln reactor in the temperature range of 450 ℃～650 ℃. The yield of pyrolytic char was about 39%～44%. Pyrolytic char contains relatively high content of ash (>12%) and sulfur. The pore volume of pyrolytic char increased with pyrolysis temperature and reached the maximum at 550 ℃. The maximum specific pore volume of char occurs at 50 nm pore diameter. Medium surface area (253 m2/g～306 m2/g) activated carbons with relatively developed mecro and macropores were obtained during activation of pyrolytic char in steam or CO2. The pyrolytic char and activated carbon exhibit excellent adsorption capacity for methylene blue and Pb2+ from solution compared with commercial active carbon. The pyrolytic char can also be used as carbon black. The characteristics of carbon black and vulcanizate of pryolytic char, such as congeries structure, tensile strength, etc, are lower than those of N330 carbon black. Pryolytic char may use as low grade carbon black and find applications in low grade rubber goods.
Abstract: A simulated light oil consisting of model sulfur compounds of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) and n-heptane as solvent was employed for the oxidative desulfurization tests in hydrogen peroxide and formic acid oxidative system. The effects of amount of agent, reaction temperature and reaction time as well as the addition of naphthalene, tetraline, cyclodexene, indole on the sulfur removal were investigated in more details. The results showed that under the condition of reaction temperature of 60 ℃, ratio of hydrogen peroxide to sulfur of 7∶1(mol/mol), ratio of hydrogen peroxide to formic acid of 1∶1(v/v), and reaction time of 40 min, the desulfurization yields of 4,6-dimethyldibenzothiophene, dibenzothiophene and benzothiophene were 100%, 96% and 58%, respectively. The addition of naphthalene and tetralin made the desulfurization yields of benzothiophene decrease, while it made a little increase for the dibenzothiophene desulfurization yield. Both the addition of cyclodexene and indole decreased the removal of benzothiophene and dibenzothiophene, in which desulfurization yield of benzothiophene decreased faster than that of dibenzothiophene.
Abstract: Oxygen-enriched combustion of coal is one of the new technologies that can control pollutants emission. Thermodynamic analysis for calcination of limestone under O2/CO2 atmosphere in fluidized bed condition was carried out, which is accorded with the TG (Thermal Gravity) results. The initial decomposition temperature of CaCO3 was increased with increasing CO2 partial pressure. Calcination and desulfurization of limestone under O2/CO2 atmosphere were performed in a fluidized bed test-facility. Calcined and desulfurized limestones were analyzed by PM (Press Mercury) and SEM (Scanning Electron Microscope). Pore structure characteristics were different between atmosphere of air and O2/CO2 ratio of 1∶4 during the process of calcination and desulfurization. Limestone sulfuration under O2/CO2 atmosphere was accompanied by calcination.
Abstract: The application of non-mechanical valve (loop seal) in a fluidized bed gasifier was studied. The result shows that the loop seal can be well applied in the fluidized bed gasifier. Working under fluidized air and flexible air or fluidized air and side air can obtain the good operation of opening/locking and controlling when the ratio of recycle chamber sectional area, supply chamber sectional area and horizontal slit area is 1∶1∶0.5. Meanwhile, the effect of pressure on the loop seal was studied. At last, the empirical equations of solid flow rate and air flow rate were obtained. The results show that predicted data is in good agreement with the experiment data.
Abstract: The rotary drying process for Fujian anthracite and alkali-salt by-product from chemical plants was studied. The factors such as coal particle size, drying temperature, drying time, gas velocity, rotary rate, catalyst component and drying capacity were discussed. At the drying temperature 80 ℃～160 ℃, drying capacity 214 kg/m3·h～1834 kg/m3·h, gas velocity 0.12 m/s～0.30 m/s and within 20 min，the moisture content of the mixture can be reduced to <5%.It shows that the rotary drying technique is very suitable for this process. The catalyst immerses into coal well and the admixture, produced from the rotary drying process, can be in good fluidization state during the gasification. The heat transfer coefficient equation for MA catalyst and Fujian anthracite is given by the regression of experimental data. Based on the mass and energy balances, the variations of drying characteristics along the rotary dryer are simulated, which is beneficial to the industrial design and analysis.
Abstract: Hydroisomerization of n-heptane and n-tetradecane over Pt/SAPO-11 catalyst with 0.6% Pt loading was carried out in a fixed-bed, down-flow reactor at 200 ℃～420 ℃, 0.5 MPa, WHSV of 2.0 h－1. Under such conditions, 90% selectivity to isomers was achieved at high n-alkane conversions. When the conversion was less than 55%，C7 and C14 followed the same reaction pathway, which means that the relative reaction rates of isomerization to cracking were same for both alkanes. Based on the product distribution, the reaction network of the n-alkane hydroconversion over Pt/SAPO-11 was proposed. Moreover, the results of the catalytic reaction tests strongly suggest that the isomerization of paraffin occurs inside the SAPO-11 channel.
Abstract: The gaseous phase synthesis of diethyl oxalate and oxalic acid with CO was an important project of C1 chemical technology because CO source was abundant and its oxygen content was 57%. This process is a new green chemical technology. The catalysts for the titled reaction were prepared with impregnation method. The performance of Pd-Me/Al2O3 catalysts for the synthesis of diethyl oxalate from CO in gaseous phase were optimized and evaluated in a fixed-bed flow reactor with industrial feed gases that includes oxygen, H2O, and sulfur. The influences of Pd loading, the molar ratio of Pd to promoter Fe and the type of Al2O3 supports on the performance of the catalysts were investigated. It was found that the performance of the catalyst was appropriate when the Pd loading was 1%～5%, Pd/Fe molar ratio was 0.2～2.0 and the supports were bar α-Al2O3 carriers. The yield of diethyl oxalate was more than 900 g/L·h－1 with the conversion of CO over 63% and the selectivity to diethyl oxalate more than 95%, and the catalysts was stable.
Abstract: NiP amorphous alloy catalysts were prepared via three different ways, reduction of Ni2+ by NaH2PO2 (method 1), self-oxidation and reduction of Ni(H2PO2)2 (method 2), and the reduction of Ni2+ by H3PO2 with amine adjusting the pH value of solution (method 3). All the NiP samples have amorphous structure inferred from the X-ray Diffraction (XRD) patterns. But the catalysts prepared by the two new methods show smaller particle size and higher surface area than the samples by method 1, and they show higher catalytic activity in the hydrogenation of sulfolene evaluated in a 250 mL autoclave. In order to exhibit the influence of preparation methods on properties of NiP samples, three samples were prepared at the same conditions via different ways, respectively, which were signed as NiP-4 (from method 1), NiP-5 (from method 2) and NiP-9 (from method 3). Transmission Electron Microscope (TEM) images show these samples have different shapes and sizes. NiP-4 sample has not very regular shape. NiP-5 particles are isolated balls while the shape of NiP-9 is near spherical. Their average particle sizes are about 160?nm, 30?nm and 10?nm, respectively. Extend of surface oxidation increases with the particle size decreasing. Crystallization performance of these amorphous alloys is determined by Differential Scanning Calorimetry (DSC) analysis. Their crystallization temperature is in the order of NiP-9 (682 K) > NiP-5 (679 K) > NiP-4 (625 K), which means their structure stability in the same order.
Abstract: This work aims at exploiting a kind of catalyst as a substitute of imported catalyst for LPG steam reforming. The Ni based catalysts were prepared by impregnation of nickel nitrate solutions on four kinds of supports respectively. Support SA was prepared by co-precipitation from a mixture of the solutions of Na2SiO3·6H2O and Al(NO3)3·9H2O by means of a solution of NH4·H2O at 343 K and pH=6.5. Support AS was prepared in different precipitation sequence compared with support SA. Support MC’s were prepared with modified natural mineral as raw materials. MC-1 was calcined at 1 100 ℃ and MC-2 at 900 ℃. The LPG steam reforming reactions were carried out at atmosphere in a continuous -flow type fixed-bed reactor. The effects of supports on steam reforming activity are investigated. X-ray Differaction (XRD), Thermal Gravity-Differential Thermal Gravity (TG-DTG) and Transmission Electron Microscope (TEM) are used to characterize the catalysts. The catalytic activity of the catalysts were studied at 750 ℃ and water/hydrocarbon=2.0. The results were as follows: the catalysts prepared in our lab have excellent activity for LPG steam reforming reaction compared to the traditional Ni/α-Al2O3 catalyst. The activity of Ni/SA catalyst was superior to others. Under the optimized experimental condition, 100% conversion and 94.46% selectivity were obtained. Support SA calcined at 1300℃ was mainly composed of α-Al2O3 and Si2Al6O13 crystal. The precipitation sequence of supports significantly affected the catalyst activity. The catalyst prepared with Si-Al precipitation sequence is better than that of Al-Si sequence.
Abstract: A compact planar reformer for methanol reforming was designed and tested. The advantages of the reformer are that it is very compact, easy to be placed on board and scaled up. The reforming chamber two vaporization chambers, two combustion chambers and four heat exchange chambers are all integrated in one unit as the reformer. The effects of the ratios of O2/methanol and water/methanol on the performance of the reformer were investigated. In addition, the temperature distribution of different chambers in the reformer was studied. When the space velocity of methanol was 4 000 h－1, the gas output of the unit reached 3 m3/h～5 m3/h..
Abstract: Bifunctional catalysts for FCC gasoline hydroupgrading were synthesized using Hβ as support, Ni as the active component and P, Mg and La as promotor respectively in this experiment. Effects of different calcining methods to eliminate template agent on Naβ carrier were studied. Effects of species and content of auxiliary on the properties of the catalysts were studied. The results showed that stage-by-stage calcination could prevent effectively the molecular sieves from eliminating aluminum and keep well the original crystallites and the specific surface area. In the reaction of FCC gasoline hydroupgrading, alkene content of gasoline can be decreased effectively and conversion of alkene can reach 65% using Ni-β catalysts modified with P (mass percent: 0.25％). At the same time, it can also ensure basically octane number not reduced.
Abstract: Sol-gel method involving supercritical fluid drying technique was employed for the preparation of ZrO2-based materials, and NiO/CuO-ZrO2 catalysts were prepared. Reaction activity evaluation was carried out in a micro-reactor with gas chromatograph with the rise of temperature up to 1 000 ℃, and the results indicated that NiO/CuO-ZrO2 was a kind of proper catalyst in methane combustion, and most of the catalysts led to the full conversion of methane at about 700 ℃ without the production of CO. The effect of calcination temperature, CuO and NiO contents were investigated for the catalytic activity and stability of methane combustion at high temperature(1 000 ℃). Also the BET surface area, pore size distribution and X-ray Diffraction (XRD) pattern were measured. The results show that proper calcination temperature is 500 ℃, and when both NiO and CuO contents are 5 mol%, the catalyst shows high activity at relative low temperature, and when both NiO and CuO contents are 15 mol%, the catalyst shows high stability at high temperature.
Abstract: In view of not uniformity in conventional coprecipitation preparation, urea was used as the precursor of precipitator to prepare Cu/ZnO/Al2O3 catalysts for methanol synthesis. In the method, urea was dissolved in nitrate solution and hydrolyzed to produce OH－ as precipitator after the solution was heated to 90 ℃. After 6 h, the precipitation was accomplished. The evaluation results of the catalyst activity showed that this catalyst had comparable catalytic activities to the industrial catalyst, and reached its maximum activity at 250 ℃. At reaction conditions of 250 ℃, 3 MPa, and SV=7 600 h－1, the STY of methanol was 0.38 g/(mL·h) with syngas compositing of H2,CO, CO2, and N2 at molar ratio of 65.9∶27.1∶2.9∶4.1. X-ray Diffraction (XRD) revealed that the particle size of CuO and ZnO was about 200 nm, and Al existed in the form of ZnAl2O4 spinel in the catalysts.
Abstract: Mesoporous silica molecular sieve (denoted MDL) has been prepared by the hydrolysis and condensation of tetraethylorthosilicate (TEOS) in the presence of industrial production N-dodecyl-1, 3-diaminopropane surfactant, which act as the structure-directing (templating) agent, through a supramolecular assemble mechanism between the gemini surfactant and Si(OC2H5)4-x(OH)x silica precursors. The mesoporous molecular sieve has vesicle-like particle texture and lamellar framework, as confirmed by Scanning electron microcopy (SEM) and Transmission electron microcopy (TEM). The most prior preparation condition is mentioned from the influence of preparation conditions to as-synthesized samples by X-ray power diffaration (XRD). FT-IR spectra show the existence of the mesoporous silica framework.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
