Abstract: The formation of Nox precursors (HCN and NH3) during the coal combustion at 400 ℃～900 ℃ was investigated in a fluidized bed reactor made of quartz tube, in which the concentration of HCN and NH3 was measured by an ion chromatogram system and the coal combustion characteristic under the air atmosphere was analyzed by a TG-DTA (Thermogravimetry-Differential Thermal Analysis) system. The results show that the nitrogen in the coal can produce high proportion of HCN and NH3 during combustion. In the temperature range 400 ℃～500 ℃, about 50%～70% of coal-N was transformed to HCN and NH3. It can be clearly seen that not only the volatile-N of coal but also the char-N can produce NOx precursors. It is very different from the pyrolysis experiments at same temperature. The combustion of coal sample at temperature higher than 700 ℃ will yield less NOx precursors due to the increase of HCN and NH3 transformed to NOx.
Abstract: The simulation analysis on the effects of O/C ratio and coal concentration in the coal-water-slurry (CWS) on the flow and temperature fields of gasifier, gas composition and carbon conversion in the CWS gasification was conducted. The questions and resolving methods which are often met with the simulation of CWS gasification process at a high temperature and a high pressure with complex chemical reactions were discussed. The temperature, velocity and concentration fields in the gasifier as well as coal gas composition were predicated. The predicated results were very close to the engineering data. Furthermore, the effects of O/C molar ratio and coal concentration in CWS on the CWS gasification process and coal gas composition were analyzed and the measures to increase the effective coal gas components (CO+H2) were proposed.
Abstract: Xinwen CWS (Coal-Water-Slurry) and black liquor CWS were combusted in a 0.25?MW combustion furnace, and the slag produced along the furnace was measured and analyzed to determine the distribution of mineral species such as Na, K, Ca, Al, Si and Fe. The influence of mineral species on the fusion is discussed. The result shows that the distribution is different among the mineral species along the fire in the furnace. For example, Na2O on the wall is less than that in the volume, and the distribution increases firstly, then decreases after it reaches the peak at 1 000 mm. And the distribution of some other mineral species has their own rule which is consistent with the fusibility of the coal ash.
Abstract: The effects of 6 dispersants on the amounts of Ca2+, Mg2+, Fe3+(Fe2+), Al3+, and SiO32－ ions extracted from 14 Chinese coals were studied by atomic adsorption spectrometry (AAS) and inductively coupled plasmatorch-atomic emission spectrometry (ICP-AES). The results show that many dispersants accelerated the dissolution of Ca2+ ion from coals, but were not obvious to that of Mg2+ and Al3+ ions. The influence of different dispersants on dissolved Fe3+/Fe2+ ion depends on the kinds of mineral matters in coal. The amounts of dissolved high-valence cations from coals mainly depend on the interaction between dispersants and coals, as well as the kinds and amounts of mineral matters in coals. There is no certain relativity between the amounts of dissolved cation and corresponding metal oxide in coal ash. The slurryability or rheological behavior of coal water slurry (CWS) is not simply dependent on the amounts of high-valence cations. The effect of mineral matters in coals on CWS properties is an integrated result of many factors, and the kind and amount of dissolved inorganic ions are only some of the important factors.
Abstract: The alumina supported copper oxide sorbents named XP and DS were prepared by impregnation method, and cycles of sulfation-regeneration reactions were carried out in a quartz tube reactor. The effects of the physical properties of the supporter on SO2 sorption capacity of the sorbents, as well as the changes of the surface microstructure of the sorbents during sulfationregeneration reactions were determined by BET, XRD and EP (Electron Probe). The results show that the γ-alumina used for sorbents should have both the large surface area and the ideal pore size. Above 90% desulfurization efficiency has been obtained by the prepared sorbents under the experimental conditions. These sorbents exhibit a good stability in the cycles of sulfation-regeneration reactions.
Abstract: Pressure distribution of the riser and the standpipe of a cold model CFB (Circulating Fluidized Bed) reactor combined with a coal pyrolysis reactor was studied by using sixteen channels pressure sensors. The riser column is 0.1 m in diameter and 6 m in height. And the standpipe is 0.044 m in diameter and 3 m in height. The rectangle pyrolysis chamber that has a cone-shaped gas distributor with a cross section of 200 mm×200 mm and 0.77 m in height lays between the cyclone dipleg and the standpipe. The effects of the superficial gas velocity in the riser, the circulating rate, the aeration to the pyrolysis chamber and the initial inventory on the pressure distribution of the system were investigated. The results showed that the pressure gradient in the riser and standpipe was gradually decreased with the superficial gas velocity, while it was increased with the circulating rate at the constant superficial gas velocity. The effect of the aeration to the pyrolysis chamber on the pressure distribution of the standpipe was more remarkable than on the riser. Moreover, increasing the initial inventory would lead to the increase of pressure distribution of the riser and the standpipe.
Abstract: Under the simulated conditions of coking chamber, the coking process of coking coal blended with plastic and sulphur sorbent was investigated. The H2S removal efficiency of coking oven gas (COG) and the contents of residues of sulphur and zinc in the coke were also analyzed. The experimental results indicate that for the coking process of coking coal blended with ZnO, Fe2O3 or metallurgical dusts (MD), the removal efficiency of H2S in COG was satisfying when the molar ratio of sorbent (ZnO and/or Fe2O3) to the volatile sulfur in the mixture of coal and plastic (nZn+Fe/nS) is 1.2. The desulfurization activity of MD is relatively lower than that of ZnO and Fe2O3. Because of the thermal cracking behavior and chemical composition of plastic, the coke yield decreases from 81.5% for the coking-coal to 77.61% for the coking-coal with 5% of plastic added. However, if 5% of plastic and ZnO are added into the coking-coal, a satisfying removal effect of H2S in COG can be obtained when nZn+Fe/nS is increased to 1.7 due to the relative higher sulphur content in the plastic, while the contents of sulphur and zinc in the coke increase to some extent.
Abstract: Kaolin is a low-cost and abundant resource in nature. Its product, superfine kaolin, was used as additive to prepare CaO-kaolin complex sulfur fixing reagent. The sulfur fixing efficiency of CaO-kaolin is studied by thermogravimetric technique. The results are compared to that of CaO. The conversion of CaO in CaO-kaolin is improved much more than that of pure CaO by 26% when reacting at 100 9 ℃. The grain model of reaction kinetics is used to describe the sulfur fixing process of CaO-kaolin. Because of increasing synchronously, the kinetic data of activation energy Ea and the gene k0 can't reflect the activity of sulfur fixing reaction. Reaction velocity k, diffusion coefficient DS of CaO and CaO-kaolin at different temperatures show that CaO-kaolin has better reaction performance because kaolin greatly improves the diffusion coefficient DS.
Abstract: The molecular weights of asphaltene, resins and aromatics in Daqing, Shengli, Gudao and Liaohe vacuum residua were determined using benzene, chlorobenzene and nitrobenze as solvents, respectively. The molecular sizes of these sub-fractions were calculated according to a spherical molecular model, and the micellar particle model for asphaltene in vacuum residua was built. It is shown that primary asphaltene molecule size is about 3.8 nm～5.0 nm, 3.2 nm～3.7 nm and 2.8 nm～3.2 nm respectively in benzene, chlorobenzene and nitrobenzene solvents. The micellar sizes of asphaltene are about 10.0 nm～11.0 nm in Daqing, Shengli and Liaohe vacuum residua, and about 9.0 nm～10.0 nm in Gudao vacuum residuum.
Abstract: The specific surface area and pore volume of partially gasified petroleum cokes of different conversions are determined. Change of pore structure of partially gasified petroleum coke and its relationship with the gasification rate are investigated. The results show that pores of petroleum coke are mainly micropores. The specific surface area and pore volume increase with carbon conversion during steam gasification. Gasification rate plots changes differently for petroleum coke with different porosity and surface area. The reactivity has a close relationship with pore structure. There is a good linear relation between the specific gasification rate and the effective specific surface area.
Abstract: Fast pyrolysis and combustion properties of RDF (Refuse derived fuel) in thermobalance and tubular furnace at isothermal condition were investigated. Both pyrolysis and combustion of RDF have very fast reaction velocities. It takes 60 s～80 s to finish reaction from the time being heated, and about 20 s to complete reaction from weight loss occurred. The combustion profile of RDF is very similar to pyrolysis profile, only one weight loss region is found for both. The volatile matter of RDF firstly gives off and then burns, and the subsequent char is burnt simultaneously. The results show that the composition of RDF has effect on its pyrolysis and combustion reactivity. The RDF containing tyre has lower pyrolysis and combustion reaction velocities. There are 80%～90% of gas and liquid and 10%～20% of solid among pyrolysis product of RDF during fast pyrolysis at isothermal condition from 650 ℃ to 800?℃. The pyrolysis gas has higher heating value of about 20 kJ/m3 and RDF is suitable for pyrolysis.
Abstract: Aimed at producing hydrogen-rich gas, pyrolysis of rice straw and sawdust was carried out in a fixed-bed reactor at different temperatures with catalyst (Cr2O3, MnO, FeO, Al2O3, CaO, CuO and Na2CO3). The results show that at current operating conditions, total gas yield and hydrogen-rich gas yield are low. However, it could be improved by using catalysts. The addition of Cr2O3 at 750 ℃ leads to the increase of the total gas yield by 10% and the concentration of hydrogen-rich gas by 13%. High temperature favours the yield of total gas and the concentration of hydrogen-rich gas. When the temperature rises from 500 ℃ to 850 ℃, the yield of total gas and the concentration of hydrogen-rich gas, for rice straw pyrolysis, increase from 29.0% to 40.6%, and 41.2% to 48.2%, respectively; for sawdust pyrolysis from 35.0% to 46.5%, and 40.6% to 47.0%, respectively. The catalysts used exert positive effect on pyrolysis of rice straw and sawdust, however, Cr2O3 appears stronger catalytic role than other metal oxides. 30% catalysts (CaCO3, Na2CO3) is recommended because higher amount of catalyst almost does not improve catalytic activity again. The addition of CaCO3 or Na2CO3 increases the yields of total gas and also of hydrogen-rich gas. Catalytic performance of Na2CO3 shows a little bit better than that of CaCO3 in the case of rice straw pyrolysis.
Abstract: The coked zeolite catalyst FX-02 used in synthesis of ethylbenzene with dry gas of FCC (Fluid Catalytic Cracking) was studied by TPO（Temperature Programmed Oxidation） experiment, by which the coked catalyst was regenerated. The acid properties of the regenerated catalyst were investigated by NH3-TPD(Temperature Programmed Desorption) and compared with the fresh catalyst. Pore structures, activity, crystal phase and specific area were also studied. The components of the coke on the catalyst were analyzed by GC/MS(Gas Chromatography/Mass Spectrometry). The experimental results illustrated that the coke deposited on the active site center of the catalyst led to the catalyst deactivation and could be burned out when the temperature was over 300 ℃. The coke was most compatibly burned at 500 ℃～550 ℃ and burned off completely at 600 ℃. It was also shown that the acid sorts and proportion can be restored completely through regeneration at 550 ℃. The percentage of restored acid amount exceeded 95% and the crystal and the pore structure were nearly as same as the fresh catalyst. The assessment of intrinsic activity of the regenerated catalyst was satisfied by compared with that of the fresh catalyst.
Abstract: The catalytic performance of LaMnO3, La-Mn1-x-CuxO3, La0.8Sr0.2-Mn1-x-CuxO3, and La0.8Ba0.2-Mn1-x-CuxO3 for the title reaction was tested in the gas mixture of 1% CO, 0.5%～2% O2, 50% H2 in N2 and at a space velocity of 40 000 mL·g－1·h－1. The results show that the partial substitution of Cu for Mn in LaMnO3, and the partial substitution of Sr or Ba for La in La-Mn1-x-CuxO3 can enhance its catalytic activity. Among the catalysts investigated, the highest catalytic activity was observed over La0.8Sr0.2Mn0.5Cu0.5O3 catalysts: CO was completely converted to CO2 at 155 ℃ with a corresponding selectivity of 54%, which is close to the catalytic performance of some platinum catalysts. The conversion of CO was lowered with the addition of 15% CO2 in the reactant gas. The addition of 10% H2O in reactant gas reduced the CO conversion more markedly.
Abstract: The catalyst used for the slurry phase hydrocracking of VGO (Vacuum Gas Oil) from Kelamayi, Xinjiang, was separated from the products and analyzed by using XRD and XPS. The crystal structures of the catalysts were identified as NiS（Ni7S6）, MoS2 and Fe1-xS. The catalytic performance of molybdenum, nickel and iron was studied respectively for the slurry phase hydrocracking using diphenylmethane as the model compound and VGO from Kelamayi as the reactant. The results showed that, during the slurry phase of heavy oil hydrocracking, the catalyst of metal sulfide reacted on the chemical reactions. The free-radical intermediate H· formed on the surface of the catalyst could react with the free-radical of big molecular and restrained the formation of coke during the reaction.
Abstract: A novel desulfurizing agent (DA) was developed to remove carbon disulfide in one step at relatively low temperature. Catalytic hydrolysis and catalytic oxidation were combined on this desulfurizing process. The mechanism to remove carbon disulfide in one step was confirmed by the experiment. The effects of temperature, space velocity, CS-2 concentration, relative humidity, the ratio of O/S were also investigated. From the experimental result, a high sulfur capacity of 2.64 mg/m3 was obtained at the condition of 130 ℃, 1% of relative humidity, 2 of the O/S ratio, 600 h－1 of space velocity. The chemical analysis of basic and sulfuric acid on the catalysts showed different tendency on the catalysts. The decrease of OH－1 was attributed to the formation of SO42－. High ratio of SO42－ to total S-yield had negative effect on the sulfur capacity.
Abstract: Zr-MCM-41 mesoporous materials were prepared via a direct-synthesis method using Zr(NO3)4·3H2O as a precursor. The samples were characterized with XRD (X-ray Diffraction), TG-DTA (Thermogravimetry-Differential Thermal Analysis) and N2 adsorption. The effects of Zr/Simolar ratio on the Zr-MCM-41 were then investigated. The results show that the peak of 100 near 2θ=2° in XRD patterns becomes weaker with the increase of Zr/Si molar ratio. To obtain the mesoporous Zr-MCM-41, the maximum of Zr/Si molar ratio is 0.25. The BET area of the Zr-MCM-41samples decreases with the increase of Zr/Si ratio, but the pore size keeps as 2.75nm～2.97nm.
Abstract: The promotional effect of Ce, La and Ca on the catalytic performance of Ni catalyst was investigated. The results indicated that the effect of promoters on Ni/α-Al2O3 is better than that on Ni/γ-Al2O3. Ce was proved to be the best promoter among the three promoters tested and the effect of different loadings of promoter Ce on the catalytic performance was investigated.The results showed that the optimum content of Ce was 1%. The effect of Ce loading on 10%Ni/γ-Al2O3 catalyst was investigated by XRD, XPS and TG techniques. XRD result indicated that Ce was highly dispersed at low loadings, but crystallized into bulk CeO2 at higher loading, thus, decreased the catalytic activity.
Abstract: A series of catalysts composed of Mo-Bi-Co-Fe-Ce-Cs-K were prepared by orthogonally varying the three key factors, the concentration of ammonium paramolybdate solution, pH value and calcination temperature. The physico-chemical properties of the catalysts were characterized by BET, TG-DSC and XRD. The catalytic performance for selective oxidation of isobutylene to methacrolein was studied by using a continuous fixed bed micro-reactor under atmospheric pressure. The results indicated that the activity of the catalysts increased with surface area increasing, and the selectivity decreased with pore diameter decreasing. The optimum preparation conditions of the catalysts were that the concentration of ammonium paramolybdate solution was 10%, pH ranged from 2 to 3 and calcination temperature was 500 ℃. For the catalyst prepared at the optimal preparation conditions, the experimental results showed that isobutylene conversion was 87.2%, selectivity to methacrolein was 72.0% and the yield of methacrolein was 62.7% at the experimental conditions of isobutylene∶air=6∶94, GHSV=3 600 h－1 and reaction temperature=360 ℃.
Abstract: Ultrafine Cu/ZnO/TiO2-SiO2 catalysts with different content of Cu and Zn ranging from 5% to 25% were prepared by sol-gel method. The physical-chemical properties and catalytic performance of the catalysts were studied by using FT-IR(Fourier Transform InfraRed), BET,TPR(Temperature Programmed Reaction),XRD(X-ray Diffraction) and micro-reactor system. It was found that the catalysts exhibited large BET surface area(590 m2g－1～240 m2g－1) and uniform pore distribution. XRD showed that only crystal phase detected was CuO. With increasing content of Cu and Zn in the sample, the BET surface area of the catalysts gradually decreased, the average pore diameter and the junction temperature of CuO micro-crystal increased, the dimensions of the micro-crystal increased from 10 nm to 20 nm. The presence of ZnO can promote the interaction of CuO and TiO2-SiO2 support. The catalysts showed high activity and selectivity to methanol. When the content of CuO and ZnO both were 25%, a methanol yield of 0.126/g·h－1·g cat－1 was obtained under the conditions of 260 ℃, 2.0 MPa, 2 500 h－1 with a CO2/H2 ratio of 1/3.
Abstract: Cu-Zn-Al-Mn, Cu-Zn-Al-Ce and Cu-Zn-Al catalysts were prepared by coprecipitation method. Their activities were evaluated using a feed gas composed of H2(66%),CO(27%),CO2(3%) and N2(4%). The results indicated that Mn was an effective promoter to improve the activity and thermal stability of Cu-Zn-Al catalyst. The study of catalyst characterization using XRD (X-ray Diffraction) and SEM (Scanning Electron Microscopy) also showed that Mn promoter was favorable for the dispersion of CuO. The activity of Cu-Zn-Al-Mn catalyst was further evaluated using a CO2-rich feed gas composed of H2(50%),CO(25%),CO2(20%) and N2(5%). The results indicated that both STY (space time yield) and selectivity of methanol were decreased when CO2-rich syngas was used. Under tested ranges, the STY was decreased 11%～25% and the selectivity was 93% to 95%, decreasing in the range of 3.5%～5.7%.
Abstract: Zr/HZSM-5 zeolites were synthesized by hydrothermal method with water glass, aluminum sulfate, zirconium nitrate and n-butylamine (NBA) as the template. The synthesized samples have been characterized by XRD, SEM and NH3-TPD. The results of XRD indicate that the Zr/HZSM-5 is regularly ZSM-5 zeolite and the introducing of zirconium atom changed the size of unit cell. The SEM photographs show that the granule was a well crystallized claviform crystal about 3 μm～5 μm in length. The NH3-TPD curves show that the number of medium acid and strong acid sites increased almost linearly with the content of zirconium. Propene oligomerization reaction was carried out over the samples to evaluate the catalytic properties of Zr/ZSM-5 zeolites. The catalytic capability of Zr/HZSM-5 changed with varying of the number of medium acid and strong acid sites, which can accelerate the increasing of chain.
Abstract: Physicochemical and catalytic properties of steam treated phosphorus-modified- HZSM-5 zeolites have been investigated. XRD and IR show that no new crystalline phase exists in the modified samples. Acidic properties of the samples have been characterized by ammonia temperature programmed desorption (NH3-TPD), indicating the introduction of phosphorus by impregnation of the zeolite with an aqueous solution of NH4H2PO4 and steam treatment decrease the number of acid sites. After steam treatment, BET surface area decreases remarkably due to the blockage of channel by phosphorus species and dealuminated species. The nitrogen adsorption-desorption measurements suggest that the isothermal type of all samples is a combination of type I and type IV, all hysteresis loops resemble the H4-type in the IUPAC classification. The conversion of n-heptane over steam treated P-modified-HZSM-5 zeolite is higher than that of sole steam treated zeolites, showing a protective effect of the phosphorus against dealumination by hydrothermal treatment at elevated temperature.
Abstract: Biomass can be converted into bio-oil by pyrolysis with high heating and cooling rates. Bio-oil is a crude oil which can be upgraded into high quality liquid fuels, for instance, it can be first gasified into syngas and then synthesized into methanol, dimethyl ether and so on. Considering bio-oil has high oxygen content, bio-oil gasification without any external supply of oxygen has been performed. The result shows that the mass conversion efficiencies of oxygen and hydrogen elements could be reached as high as 85%, but that of carbon is only 55%. Hence, the external oxygen supply should be needed to improve the mass conversion efficiency of bio-oil gasification.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
