Abstract: The aim of the present study is to obtain more information concerning organic sulphur pollutants produced by some commercial briquettes based on coal and biomass. Reductive pyrolysis technique (AP-TPR), coupled “on-line” with mass spectrometer (MS) and “off-line” with GC/MS was used for qualitative and quantitative study of sulphur compounds emitted from household briquettes. By AP-TPR-GC/MS and inner standard application, prominent sulphur containing compounds were quantitatively determined. For different briquettes some peculiarities were observed. Namely, only for biobriquette low presence of dialkyl sulphides and aliphatic thiols was registered. The highest variety of organic sulphur forms was detected for lignite briquette. Oxidized sulphur compounds were not registered for the higher coal rank briquettes but the presence of different thiophenes was typical for them.
Abstract: The gasification reactivity of six kinds of typical Chinese anthracite chars with steam and CO2 at 0.1MPa and 920℃~1050℃ was investigated comparatively using thermogravimetric analysis (TGA). The results show that the gasification reactivity of anthracite chars with steam has a good correlation with the coal rank, i.e. the higher the coal rank, the lower the reactivity. The gasification reactivity of anthracite chars with CO2 is related to the catalytic effect of mineral matter in coal, i.e. the higher catalytic effect leads to higher gasification reactivity. The gasification reactivity of anthracite chars with steam is about 10 times higher than that of chars with CO2. Gasification mechanism has been discussed preliminarily.
Abstract: The experiments on the catalytic gasification of pulverized Fujian Longyan anthracite by using black liquor as the catalyst and oxygen enriched mixing gas (oxygen enriched air/steam) as the gasification medium were carried out in a bench-scale fluidized bed reactor. The effects of catalyst (black liquor) addtive on the carbon conversion, gas yield, gas composition and calorific value were evaluated under different enriched oxygen concentrations. The results show that the dual effects of the black liquor catalyst and the enriching of oxygen in feed air can greatly improve the carbon conversion and the effective composition of gas products. However, the catalytic gasification of coal by alkali in black liquor and the calcination (vitrification) reactions of SiO2 and Al2O3 in coal ash with alkali in black liquor coexist in the same process, and these reactions exhibit a certain competition at 870℃. In addition, a series reactions between carbon and gas medium at high temperature may be enhanced differently by alkali in black liquor. Based on the experimental results and above analysis the optimum operation condition for the black liquor catalyzed gasification of Fujian Longyan anthracite in enriched oxygen medium is proposed. The oxygen concentration of 40% and the ratio of steam to oxygen enriched air ranging from 1.4kg/m3 to 2.0kg/m3 will have the best results，such as 94% of carbon conversion, 3.62m3/kg of gas yield and 7.33MJ/m3 of calorific value of gas products.
Abstract: Based on the widely accepted catalysis mechanism and the reasonable assumptions, a new kinetics model, active site extending model was developed to describe the catalytic coal char gasification rate more properly. The model was validated with the experimental results of CO2 catalytic gasification of Shenfu coal char at various temperatures by using KCl and K-Ni compound catalysts, and the model parameters for Shenfu coal char gasification were obtained. The kinetic behaviour and catalytic mechanism are well explained by active site extending model. The maximum error between the simulated and experimental results is about 10%. It is also revealed that the catalysts can effectively improve the gasification rate and reduce the gasification temperature by increasing the active surface area and sites. A slight disagreement between the simulated and experimental results can be attributed to the mass transfer resistance during the initial reaction stage.
Abstract: The kinetics of the reaction between coke and CO2 under the condition of blast furnace was studied by using the shrinking unreacted core model, and a relational expression of reaction kinetics was established with R, a determinable parameter. Reaction rate constant, effective diffusivity, apparent activation energy, effective diffusion activation energy and resistance in various steps of the reaction process were analyzed in this paper. The results show that the reaction of coke with CO2 is consonant with the shrinking unreacted core model, which has an apparent activation energy Ea=124.5kJ/mol, and an effective diffusion activation energy ED=642.4kJ/mol. With the increasing of reaction temperature, the resistance of surface chemical reaction increases, but the relative proportion of internal diffusion mass transfer resistance decreases in the residue ash layer. The coke reaction with CO2 is mainly controlled by the internal diffusion at lower temperatures, while with the increasing of reaction temperature, it is controlled by a combination of external diffusion, chemical reaction and internal diffusion. After a period of time at high temperatures the reaction turns to be controlled by the internal diffusion.
Abstract: Fly ashes, obtained from three commercial CFB boilers with burning Fujian anthracites, were studied in this paper. By using standard dry-sieving techniques and LOI method, the size distributions of fly ashes and the carbon contents of different size fractions were measured. With the help of SEM and EDX technique, the particle superficial property of fly ash was examined and divided into carbon (soot, or graphite), char, and slag. The residual carbon was enriched from fly ash by the floating-separation technique, and its reactivity was then measured via a non-isothermal TGA experiment. The results was compared with that of its corresponding parent coal. Furthermore, in a laboratory pilot scale fluidized bed furnace, the source of the unburned carbon in the fly ash was explored. It is shown that for CFB boilers using a single cyclone separator, the largest amount of fly ash particles lies in the particle size range from 0.0385mm to 0.0500mm, and so does the unburned carbon fraction; and for CFB boiler equipped with two separators, the largest amount of fly ash particles and unburned carbon fraction lies in a particle size range of 0.0500mm~0.0750mm. There are three kinds of particles existing in fly ashes, which are granular unburned carbon, flocculent slag and char. The reactivity of the unburned carbon in fly ashes is relatively higher than that of its parent feeding coal. It can be induced from this study that the unburned carbon in fly ashes comes primarily from the fines existed in the fed coal and produced by the attrition and fragmentation of coal particles, which cannot be totally burned in the earlier stage of combustion. The clarain, which is of high reactivity and frangible, may be the main originations of unburned carbon in fly ash.
Abstract: The behaviors of mineral matters in coal at high temperature were investigated under reducing atmosphere. X-ray diffraction and SEM-EDX were employed to observe phase changes and reactions of mineral matters. It is found that the phase composition and reactions of mineral matters are basically consistent with ternary phase diagram of CaO-SiO2-Al2O3. The system of mineral matters is mainly dominated by the change of Ca-aluminosilicates. The residence time influences both the crystalline and amorphous characteristics of mineral matters. The amounts of the amorphous phase appear to be dependent on the stability of the eutectic mixture. Under reducing atmosphere, FeO-FeS system has a significant influence on the mineral behaviors and morphologies.
Abstract: Three sodium polystyrene sulfonate (PSS) additives with different molecular weight and 8 coals are selected to evaluate the effect of molecular weight of PSS on the properties of coal water slurry (CWS). The range of weight average molecular weight of PSS for preparing coal water slurry is from 53400 to 333900. The results indicate that the slurryability of CWS of 8 coals decreases as the molecular weight of PSS increases. The relation between slurryability of CWS and molecular weight of PSS is attributed to the adsorption of PSS on the coal particles. The adsorption quantity of PSS with low molecular weight on the coal particles is larger than that of PSS with high molecular weight. On the other hand, the rheological behavior of CWS of 8 coals is changed from dilatant flow to pseudoplastic one as the increase of molecular weight of PSS. The static stability of CWS is also improved with increasing molecular weight of PSS.
Abstract: The gasification of the mixture of biomass and coal in a thermogravimetric apparatus (TGA) and a fluidized-bed was investigated. TGA was used to characterize the H2O-char gasification of rice haulm char, broomcorn haulm char, cornstalk haulm char and Shenmu coal char. The results show that the order of reactivity of various chars is as follows: Shenmu coal char < cornstalk haulm char < rice haulm char < broomcorn haulm char. The co-gasification rate of the mixture of biomass char and coal char is found to be higher than the rate sum of single coal char and single biomass char，which suggests that a synergistic effect takes place due to the co-gasification. In fluidized-bed gasification experiments, the carbon conversion and the content of burnable gas of co-gasification are higher than that of coal gasification alone, while the content of CO2 is lower. H2 and CO2 contents varying with the ratio of feeding oxygen to feeding carbon show different tendency between co-gasification and coal gasification. It implies that the co-gasification is affected by not only the reaction rate but also the gas-solid hydrodynamics in fluidized bed gasifier.
Abstract: The pyrolysis of palm oil wastes was carried out using thermogravimetry (TG). The results show that these wastes are easily to be decomposed. The weight loss rang is from 220℃ to 400 ℃ at slow heating rates. Shell and fiber display similar pyrolysis characteristics with two peaks in weight loss rate curves, whereas EFB just shows one sharp peak. Their kinetics parameters were calculated using non-isothermal integrated method. The activation energies are quite low (≈60kJ/mol), and first order reaction is suitable for biomass pyrolysis. The gas product evolved from palm oil wastes pyrolysis was detected on-line with Fourier transform infrared spectroscopy (FTIR). The main gas products are H2O, CO2, CO, CH4, and some organics carbohydrate mixtures. They show the similar evolution trend of weight loss at 200℃～400℃. With temperature increasing further, except trace amount of CO2 and CO, almost no other volatile is released. CO2 and organic mixtures play a great role in biomass pyrolysis. This fundamental study provides a basic insight of the palm oil waste pyrolysis, which can benefit the work in developing an advanced thermal process for high-yield biofuel production from palm oil wastes.
Abstract: One technique using hydrogen donor was introduced for super heavy oil upgrading and reducing viscosity under steam injection in well. The main factors and rules in aqua-thermolysis reaction were analyzed through comparison of viscosity，asphaltene and sulfur content before and after super heavy oil upgrading. The results indicate that a certain content of sulfur existed in super heavy oil is one of the necessary conditions in aqua-thermolysis reaction at temperature of steam injection. Temperature and time have an important effect on aqua-thermolysis reaction. Among hydrogen donors tested, tetralin has the biggest effect on super heavy oil aqua-thermolysis. The combination of tetralin and catalyst of nickel sulphate has a synergetic function to the reaction. The physical simulation experiment of aqua-thermolysis under a certain condition shows that viscosity reduction ratio can reach about more than 70% after hydrogen donor catalytic aqua-thermolysis for the super heavy oil of Shengli Shanjiasi oilfield. The content of asphaltene, colloid and sulfur decreases, and H/C increases after upgrading process.
Abstract: A series of ultrastable Y zeolites with varies Si/Al mol ratio prepared by different dealumination methods have been investigated. After modification by lanthanum incorporation and aging at 800℃ in 100% steam for 4h, the pore structure and acidic property of dealuminated Y zeolites were characterized by nitrogen adsorption and pyridine-IR methods. The catalytic cracking performances were evaluated with microactivity test (MAT) of fluid catalytic cracking (FCC). It is found that LaFSY samples prepared by using (NH4)2SiF6 as the dealumination reactant combined with hydrothermal treatment have homogeneous framework aluminum distribution, and a performance of high cracking activity and low coke yield in FCC is obtained by controlling the dealumination extent using the dealumination method. The LaOSY sample prepared by using oxalic acid as the dealumination reactant combined with hydrothermal treatment has a large mesopore volume which gives the sample a performance of better liquid yield selectivity for residue catalytic cracking.
Abstract: The effect of partial hydrogen pressure within 3MPa~28MPa on cracking of butylbenzene and tert-butylbenzene were examined in a batch reactor. Pressure has different effects depending on the molecular structure of reactants. With the raising of partial hydrogen pressure, the cracking reaction of tert-butylbenzene is prompted, while the conversion of butylbenzene is restricted. In any case, the break of C—C bonds between the aromatic ring and the whole branch chain are promoted with the increasing of partial hydrogen pressure. Based on the above result, the effect of initial hydrogen pressure on slurry bed hydrocracking of Lungu and Karamay atmospheric residues was studied. With the raising of initial hydrogen pressure, the reactions of hydrocracking and the formation of toluene insoluble fraction are promoted simultaneously. Effects of reaction temperature and time are also discussed.
Abstract: A novel ionic liquid (IL), composite IL, which contained enough quantity of multi-center ligand, AlCl4CuCl－, was successfully synthesized. The effects of reaction temperature, reaction time, stirring speed and isoparaffin/olefine (I/O) ratio on the composite-IL-catalyzed alkylation were studied. The results showed that the research octane number (RON) of the yielded alkylate gasoline can be higher than 100 under the optimal conditions: stirring speed > 1500r/min, reaction temperature < 20℃, I/O ratio >15 and reaction time in range of 5min to 10min. The multi-center ligand, AlCl4CuCl－, should be accounted for the super selectivity of trimethylpentane (TMP) of isobutane alkylation catalyzed by composite IL.
Abstract: TiO2/SiO2 were prepared by the chemical modification reaction on SiO2, then the supported coupled semiconductors (MoO3, ZnO)-TiO2/SiO2 were prepared by isovolumic impregnating TiO2/SiO2. The surface structure, chemical adsorption capabilities, photon absorption properties and photocatalytic behaviors of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO2 were systematically investigated by the techniques of X-ray differaction (XRD), BET, temperature programmed reduction (TPR), UV-Vis DRS, IR and temperature programmed desorpsion (TPD). The surface species of MoO3-TiO2/SiO2 and ZnO-TiO2/SiO2, comprising Mo—O—Ti and Zn—O—Ti bonds respectively, have the quantum size effects due to the supports interaction. The supported coupled semiconductors MoO3-TiO2/SiO2 exhibits higher photocatalytic activity than ZnO-TiO2/SiO2, because chemisorption property of CH4 and utilization of the photo energy enhanced effectively when MoO3 was incorporated on TiO2/SiO2. CH3OH and H2 are produced by the gas-phase photocatalytic reaction of CH4 and H2O over MoO3-TiO2/SiO2 catalyst at 150℃ in a fixed-bed annular photoreactor, and the CH3OH selectivity is 87.3%.
Abstract: Ni/MgO is a kind of effective and stable catalyst for ethanol steam reforming reaction. The effect of nickel loading on magnesia for ethanol steam reforming reaction was investigated in the present paper. It is indicated, under the condition of 101.3kPa, that the activity of the catalyst increases with the increase of nickel loading on magnesia. As to the selectivity to hydrogen, there is an optimum loading of nickel (10%Ni/MgO). The hydrogen selectivity order of catalysts with different nickel loading is 10Ni/MgO>15Ni/MgO>12.5Ni/MgO>7.5Ni/MgO≈5Ni/MgO. The thermoanalysis results of the catalysts show that interactions between the precursors of nickel and carrier change with the nickel loading during the calcination treatment. XRD and TPR analysis prove that the crystal structure and reducibility of the catalysts are affected by nickel loading. Two kinds of interactions between the nickel precursor and carrier are proposed for 10Ni/MgO during the calcination. The oxide state crystal structure and reducibility of 10%Ni/MgO are also different from others. It implies that the selectivity of the catalyst is affected by not only the active phase Ni but also the surroundings of the active phase Ni.
Abstract: A series of cobalt-based catalysts were prepared by incipient wetness impregnation, using Degussa A300 and R106 as supports. The physico-chemical properties of samples were characterized by XRD, BET, TPR, TPO and FT-IR. Fischer-Tropsch (F-T) reaction was carried out in a fixed-bed reactor under the conditions of n(H2)/n(CO) = 2.0, GHSV = 1500h－1, p= 2.0MPa and t=210℃～ 260℃. The investigation showed that there was some relation between the Co3O4 size and the coverage of hydroxyl on the surface of supports. Organic groups covering hydroxyl on surface of support weakened the interaction strength of support-precursor combinations, and that favored the formation of Co3O4 with bigger crystallite size. The sintering of organic groups made the reaction activity and the selectivity for heavy hydrocarbons decrease.
Abstract: The storage-reduction behavior of NOx(NO and NO2) on Pd/Mg(Al)O catalyst prepared by co-precipitation followed by impregnation, was investigated in a fixed-bed reactor at atmosphere and different temperatures. The catalyst was characterized by XRD and TPD. The main path of NO storage on Pd/Mg(Al)O is that Pd firstly catalyzes NO and O2 to form NO2, NO2 then reacts with Mg(Al)O to form nitrate and NO. Pd showes little effect on the formation of nitrate from NO2 on catalysts. The NOx storage capacity on Pd/Mg(Al)O has a maximum at 350℃ for NO. At this temperature the NOx storage capacity of the catalyst prepared is no less than 300μmol·g－1, and the selectivity of H2 reducing nitrate to N2 is higher than 94% even if the catalyst is performed in 15 storage-reduction cycles.
Abstract: The Characteristic of heavy metal ions (Pb2＋，Cr3＋and Cr6＋)adsorption by carbon blacks from pyrolysis of used tires in pilot-scale rotary kiln was studied. The effect of initial solution pH, adsorption time and dosage of PCB (pyrolytic carbon black) on the heavy metal removal was examined. It is found that the initial solution pH has a great effect on the heavy metal removal efficiency. The removal of cations such as Pb2＋,Cr3＋ increases with the increase of solution pH and reaches about 100% in weak acidic and neutral solutions. Cr6＋ can be reduced to Cr3＋ in strong acidic solutions. After the second adsorption, the removal of total Cr reaches above 99%. The removal of Pb2＋and Cr3＋ increases with the increase of adsorption time and PCB dosage which have an optimum value. The adsorption of Pb2＋and Cr3＋ is monolayer adsorption which can be described by Langnuir and two-stage Freundlich equations, and the fitting exponential of Freundlich indicates that PCB has a favorable adsorption effect for Pb2＋and Cr3＋. After acid wash, the adsorption effect of PCB for Pb2＋ will be reduced.
Abstract: Carrying out the alkylation of benzene with propene over zeolites (especially ZSM-5, Y, mordenite, and β) instead of AlCl3 or phosphoric acid as catalysts can be an environmentally friendly and noncorrosive process without the release of acidic catalyst components. Performing the reaction under supercritical conditions is effective to alleviate the catalyst deactivation caused by the carbonaceous deposition. However, it is still necessary to modify the zeolites to improve the catalyst life time and to decrease the contents of by-products that may have undesired effects on the quality of subsequent products. Therefore, in this work, the properties of Hβ zeolite modified with citric acid and its catalytic behaviours on the alkylation of benzene with propene under supercritical conditions were investigated. The results indicate that the catalytic behaviour of Hβ zeolite like catalyst life, n-propylbenzene content, di-isopropylbenzene selectivity and the isomers distribution is related to the acid strength and density of acidic sites of the catalyst, which can be modified with the treatment of citric acid. High density of acidic sites with high acid strength is favorable for the transalkylation, but aggravates the catalyst deactivation, which is mainly caused by the blocking of pore structure due to coke deposition. The concentration of citric acid has a significant influence on the properties of treated Hβ catalysts. Low concentration of citric acid may enhance the acid strength and density, while high concentration may result in the decrease of acid density and the distortion of pore structure. Hβ treated with the citric acid solution of 0.5mol/L owns high density of weak and moderate acidic sites; by carrying the alkylation over it, the catalyst life prolonged about 30% and n-propylbenzene content decreased about 90% in comparison with that over the untreated Hβ catalyst.
Abstract: Ru(Schiff-base) complex, a novel catalyst for benzene hydrogenation at low temperature, was encapsulated in the supercages of zeolite Y by flexible ligand method. The results of XRD, N2-desorption, FT-IR, DRS, DTA and catalytic reaction show that Schiff-base ligands in the prepared composite catalyst changed the electronic state of central metal atom, thus made the catalyst to form transition coordinative state with reaction substrate more easily and facilitating the product formation. Compared with Ru/Y prepared by ion-exchange method, in pure benzene hydrogenation, the catalytic activity of Ru(Schiff-base)/Y increased significantly. Simultaneously, the geometry size of different Schiff-base ligands has strong influence on the catalytic performance of prepared composite catalysts.
Abstract: Carbon nanotubes (CNTs) supported Co and Co-Ru bimetallic catalysts were prepared by an impregnation method. The obtained catalysts were characterized by TEM, XRD, TPR and TG techniques in order to elucidate the dispersion of metal particles, the interaction between cobalt and ruthenium, and the reducibility of catalysts. It has been found that Ru is a promoter to enhance the reducibility of cobalt, and results in cobalt reduction at lower temperatures. The catalytic activities of the as-prepared catalysts were tested with the probe reaction of hydroformylation of 1-octene. The results show that in comparison with Co/CNTs catalysts, Co-Ru/CNTs catalysts exhibit better performance in terms of higher conversion of 1-octene and higher selectivity to C9-aldehyde. This may be due to the homogenous dispersion of small metal particles and synergic effect of Co and Ru metals in bimetallic catalysts, which can be further attributed to the promoting effect of Ru metal in the catalysts.
Abstract: Disposal of the huge piles of used tires is increasingly becoming a problem all over the world. Incineration may utilize the energy content of waste tires, but it is associated with the generation of SO2, NOx and other hazardous emissions.Pyrolysis is an alternative disposal method with the possibility for recovery of valuable products from used tires. Recently, waste processing technology based on plasma processes has received much attention due to a number of advantages such as high treatment rate, small space volume, etc. In this paper, the pyrolysis of waste tire using a capacitively coupled radio-frequency (RF) plasma reactor was investigated. The lab-scale RF plasma reactor was operated with RF powers between 1600W and 2000W, pressures between 3000Pa and 8000Pa (absolute pressure) and temperatures between 1200K and 1800K. In the tire powder pyrolysis experiments, two product streams are obtained: combustible gas and char. The physical properties (surface area, porosity, particle morphology) as well as chemical properties (elemental composition, heating value and surface functional groups) of char were examined to exploit the potential applications of the char. The results indicate that the RF plasma pyrolysis would be a useful technology for waste disposal.
Abstract: In this work, a kinetic study of the selective catalytic reduction of NO with NH3 has been carried out. After proving the operating condition that the effect of intraphase diffusion and interphase mass-transfer processes can be ignored, the selective catalytic reduction of NO with NH3 on the catalytic activity of V2O5-WO3/TiO2 has been carried out with fixing the feed gas flow rate and composition (NO, NH3, O2) while varying the catalyst loading. Based on the experimental results of NO removal efficiency, the empirical catalytic reaction rate equation of NO with NH3 has been obtained using differential analysis.The experimental result is further proved by the graphic integral method at the temperature from 320℃ to 400℃. The reaction order is 1 to NO and zero to NH3. The reaction follows the Eley-Rideal mechanism model.
Abstract: TEM, FTIR and XRD techniques are used to investigate the structure of HPWA-SBA-15. The results show that pores of HPWA-SBA-15 have regular two-dimensional hexagonal structure, and HPWA disperses well in the pore or pore wall of HPWA-SBA-15. NH3-TPD shows the HPWA-SBA-15 catalyst has acidic properties. ETBE is synthesized by the etherification reaction of alcohol and tert-butyl alcohol over several catalysts. Solid acid catalyst HPWA-SBA-15 is the appropriate catalyst which has the highest yield of ETBE than PW12/C and cation resin. The influences of reaction temperature, ratio of alcohol to tert-butyl alcohol are studied. At optimal operation condition, 30% HPWA on HPWA-SBA-15, reaction temperature 100℃, alcohol/tert-butyl alcohol molar ratio 2, the quality catalyst 0.9g and raw material 10g, the yield of ETBE is 59.55% and the selectivity is 90.2%.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
