Comparison of coal hydroliquefaction catalysed by ZnCl2-MCln (CuCl,CrCl3 and MoCl5) and ZnCl2 melts

Hydrogenation of four bituminous coals impregnated with 5 wt% of either mixtures of ZnCl₂-MCl_n (CuCl, CrCl₃ and MoCl₅) systems or ZnCl₂ was carried out using a batch autoclave system at 400° for 3 h at 9.8 MPa of initial hydrogen pressure. The ZnCl₂-MoCl₅ system showed the highest yield of the hexane-soluble (HS) fraction compared with the other systems irrespective of the coal used. The difference between the yields of HS fractions using the ZnCl₂-MoCl₅ and other systems was most marked for coals of fairly low volatile matter content, though the conversion was relatively low (47–66%), whilst for coals of high volatile matter content HS yields with the binary melt systems were high (86–91% conversion). Elemental analyses of the HS fractions indicated that the ZnCl₂-MoCl₅ system is most favourable in decreasing the average molecular weight and the heteroatom content of HS, this characteristic trend being confirmed also with five HS fractions separated by Chromatographic techniques. Both elemental analyses and molecular weights of asphaltene (benzene-soluble materials, BS) indicated that the ZnCl₂-MoCl₅ system is also most effective in cracking coal structure.     

Catalytic activities of binary metal oxides containing iron for hydrocracking of benzyl phenyl ether and diphenyl ether

Hydrocracking of benzyl phenyl ether and diphenyl ether has been carried out over a series of iron catalysts (Fe₂O₃, Fe₂O₃Al₂O₃, Fe₂O₃ZnO, Fe₂O₃ZrO₂, Fe₂O₃MgO and Fe₂O₃SiO₂) and reference catalysts ($\text{CoOMoO}{}_3\text{Al}{}_2\text{O}{}_3$, $\text{NiOMoO}{}_3\text{Al}{}_2\text{O}{}_3$ and SiO _Al₂O₃) to search for active and selective catalysts, and to elucidate the catalyst properties of relevance for CO bond cleavage. Among the iron catalysts, Fe₂O₃ZnO, Fe₂O₃ZrO₂ and Fe₂O₃MgO exhibited relatively high activities and selectivities. The important property of catalysts relevant to hydrocracking of the ethers is the ability to accomplish hydrogenation. Acidic properties of the catalysts cause condensation and rearrangement of the reactants. The features of the iron catalysts are compared with those of molybdenum catalysts, and the reaction mechanisms discussed.     

Assessment of the activities of catalysts for the hydrocracking of coal by means of hydrogen evolution

A close relation has been found between hydrogen evolution from coal-catalyst and pitch-catalyst systems and catalytic activities of liquefaction reactions. A MoO₃?TiO₂ catalyst has the highest activity and the order of activity of the catalysts for hydrogen evolution is: MoO₃?TiO₃> MoO₃?SiO₂>10% $\text{Fe}{}_2\text{O}{}_3\text{TiO}{}_2\text{?AI}{}_2\text{O}{}_3\text{>}\text{coal alone}$. The same trend was observed for benzene-soluble materials for the hydrocracking of Akabira Coal.     

Hydrogenation of Yūbari coal coated with ZnCl2-MCln (CuCl,CrCl3 and MoCl5) catalyst melts

Hydrogenation of Yūbari coal coated with 5 wt% of ZnCl₂-MCl_n (CuCl, CrCl₃ and MoCl₅) was carried out at 400 °C for 3 h with an initial hydrogen pressure of 9.8 MPa. The binary melt catalysts showed relatively higher activity in increasing the yield of hexane-solubles than did ZnCl₂ alone. The ZnCl₂-MoCl₅ catalyst melt was best in view of its highest conversion (90.9 wt%), the highest yield of hexane-soluble material (50.5 wt%) and the smallest hydrogen consumption. In terms of yield of monoaromatics of the hexane-soluble material relative to polar materials, ZnCl₂-CrCl₃ catalyst was superior to ZnCl₂-MoCl₅ although its hydrogen consumption was high. The roles of CuCl, CrCl₃ and MoCl₅ in association with ZnCl₂ in coal-hydrogenation are discussed.     

Effect of SO42− on catalytic activity of Fe2O3 for hydrocracking of coal

The catalytic activity of Fe₂O₃for the hydrocracking of a bituminous coal at 673K increases when a small amount of SO₄^2? is included in the catalyst. The effect of SO₄^2? is marked in the formation of resins, stronger polar compounds and asphaltenes.     

MoO3/ZrO2催化剂的丙烷氧化脱氢制丙烯催化性能

以十六烷基三甲基溴化铵为表面活性剂,采用溶剂热法制备系列MoO_3/ZrO_2催化剂,采用H2-TPR、N_2吸附-脱附、X射线衍射等对其进行表征,并评价MoO_3/ZrO_2催化剂的丙烷氧化脱氢制丙烯催化性能。结果表明,MoO_3负载于ZrO_2载体上制备的催化剂催化活性增加,MoO_3负载质量分数为20%的MoO_3/ZrO_2催化剂,在反应温度为600℃时,丙烷转化率27.45%,丙烯选择性44.78%,丙稀收率12.29%。     

Catalytic wall reactor: Catalytic coatings of stainless steel by VOx/TiO2 and Co/SiO2 catalysts

Catalytic wall (structured) reactors and structured supports are suitable to study the catalytic properties of nanosized materials. The coating of metallic (aluminum and stainless steel) plates by thin layers of active phase is presented in two cases, VO_x/TiO₂ and Co/SiO₂, catalysts used in the oxidative dehydrogenation (ODH) of propane and in Fischer–Tropsch synthesis (FTS) of clean fuels, respectively. The preparation of coated plates and their characterisation by various methods of physicochemical analysis are described. Both chemical and physical methods were used for coating. VO_x/TiO₂ layers were obtained by grafting of Ti (on Al or stainless-steel plates) and V (on TiO₂) alkoxides and use of sol–gel media or suspension. A silica primer was deposited (on stainless-steel plate) by plasma-assisted chemical vapour deposition (PACVD) onto which Co oxide and silica were coprecipitated from sol–gel. The catalytic experiments in the respective reactions were carried out in special plate reactors and compared with those of catalytic powders. The study shows that the coating of a metallic substrate by a catalyst is not straightforward and requires specific studies dealing with both chemistry (chemical affinity between substrate and catalytic layers) and catalytic engineering (catalytic performance in taylor-made reactors).     

Catalytic degradation of phenol in sonolysis by coal ash and H2O2/O3

This study demonstrated that coal ash, as widely distributed solid waste disposal, would function as a media for organic pollutants removal in the presence or absence of H₂O₂/O₃ under ultrasonic radiation. Coal ash could act as a catalyst to generate OH radicals with the presence of H₂O₂/O₃ and consequently enhance the phenol degradation. Experimental results showed that when using coal ash as a catalyst under ultrasonic irradiation, 83.4% and 88.8% of phenol was degraded in the presence of H₂O₂ or O₃, respectively. The degradation rate of phenol would increase with increasing amount of O₃, while there was an optimal concentration of H₂O₂ (1.5 mM) for phenol degradation. Higher dosage of coal ash could result in higher phenol degradation rates. H₂O₂/coal ash/ultrasonic system could achieve better performance for phenol degradation under more acidic conditions, while more alkaline condition in O₃/coal ash/ultrasonic system favored phenol degradation. This study provides a new approach for wastewater treatment especially when contaminated with phenolic pollutants.     

Catalytic property of Fe-Al pillared clay for Fenton oxidation of phenol by H2O2

Clay pillared with Fe-Al was synthesized as a catalyst for Fenton oxidation of phenol by hydrogen peroxide (H₂O₂). The pillaring process altered the basal space of clay, which is related to the amounts of aluminium and iron in the pillaring solution. The catalytic activity of the pillared clay was attributed to the accessible iron species, whose amount is regulated not only by the introduced iron species but also by the basal space that subsequently depends on the introduced aluminium species. The heterogeneous Fenton reaction exhibited an induction period followed by an apparent first order oxidation of phenol by H₂O₂. The induction period was proposed as an activation process of the surface iron species, which is thus enabled to complex with the reactants. The induction time (t_I) depended on temperature (T) and pH condition but irrelevant to the concentrations of phenol and H₂O₂ and the amount of catalyst. The rate of the oxidation process was evaluated with respect to the concentrations of phenol and H₂O₂, the amount of catalyst, pH and temperatures. During the catalytic reaction the trend of iron leaching showed an ascending period and a descending period, which was related to the presence of ferrous ions and ferric ions. The Fe-Al pillared was recovered through two procedures, dry powder and slurry, which have different effect on the induction period.     

Hydrocracking of Athabasca asphaltene over ZnCl2-KCl-NaCl melts with or without an additive of some transition metal chlorides

Hydrocracking of Athabasca asphaltene over molten salts has been studied at 400 °C for 1 h at an initial hydrogen pressure of 9.8 M Pa. The hydrocracking over ZnCl₂-KCl-NaCl produced 57.0 wt% of pentanesolubles (PS), 4.7 wt% of benzene-solubles (BS) and 22.7 wt% of gases together with 15.6 wt% of coke. These melts containing NiCl₂ and CuCl, respectively, were examined, the former exerting a little better influence on reducing the coke yield. A small amount of coke (3.7%) and a higher conversion attained with ZnCl₂-KCl-NaCl-MoCl₅ suggested excellent properties of MoCl₅ for the hydrocracking of asphaltene. The sulphur contents of the PS and BS were lowest with melt catalysts containing MoCl₅. A compound-type separation of each pentane-soluble showed that in the presence of melt catalyst, monoaromatic and diaromatic contents increased greatly at the expense of polyaromatics and polar materials. The trend of catalytic activity of each melt for hydrocracking of asphaltene was found to be quite different from that for the decomposition reaction of tetrahydrothiophene in a continuous flow system.     

Na-W-Mn-Zr-S-P/SiO_2催化剂上乙烷氧化脱氢反应

研究了甲烷氧化偶联六组分Na-W-Mn-Zr-S-P/SiO_2催化剂对乙烷氧化脱氢反应的催化性能.考察了不同原料气配比、温度和空速等条件下的催化剂活性.讨论了催化剂中S或P组分的含量对催化活性的影响.实验结果表明,S和P元素的加入可以提高催化剂的活性.660℃时六组分催化剂上乙烷的转化率为65.2%,乙烯的选择性为83.2%,此时得到的乙烯收率最高.乙烷与氧气比的增加有利于提高乙烯的选择性.较低反应温度时,空速的增加可以抑制碳氧化物(CO,CO_2)的生成,提高乙烯选择性.     

Catalytic effect of potassium on the rate of char-CO2 gasification

The effect of potassium on the rate of char-CO₂ gasification at 800 °C was investigated. The instantaneous rate depends on both catalyst concentration ($\text{K}\text{C}$) and the internal porous structure of the solid. At low values of $\text{K}\text{C}$ atomic ratio, the rate increases sharply with the addition of catalyst. As catalyst concentration is increased, the rate first levels off and then decreases. The levelling off is attributed to the saturation of the surface with catalytic sites. The subsequent decrease in rate seems to be due to the plugging of micropores by catalyst deposits. The reaction rate changes significantly during gasification and drops sharply before gasification is completed. The drop in rate before total conversion can be explained by catalyst accumulation and pore plugging.     

The magneto-electric effect in molten salts—2. Measurement of the magneto-electric voltage in some molten I-I inorganic salts: AgCl,KNO3 and NaNO3

The study of the magneto-electric effect on molten salts have been reported in a previous article in which were given the necessary conditions to measure a reproducible magneto-electric voltage and the results for an organic salt 1-ethylpyridinium bromide, in the molten state and in alcoholic and aqueous solutions, were compared. Here the study is extended to some inorganic II salts: silver chloride, potassium nitrate and sodium nitrate. A magneto-electric voltage is measured as a function of the magneto-electrics stress and also of the temperature of the molten salts. All the resulting graphs exhibited identical shapes and three characteristic parameters were noted which seemed to intercorrelate well. These results agree with those previously obtained from 1-ethylpyridinium bromide.     

Partial oxidation of methane to CO and H2 over nickel and/or cobalt containing ZrO2, ThO2, UO2, TiO2 and SiO2 catalysts

The influence of different metal oxide supports (i.e. ZrO₂, ThO₂, UO₂, TiO₂ and SiO₂) on the performance of Ni- and/or Co-containing catalysts [Ni and/or Co/MO₂ mole ratio (where M=Zr, Th, U, Ti or Si)=1.0] in the oxidative methane-to-syngas conversion at very low contact time (GHSV=5.2×10⁵ cm³ g⁻¹ h⁻¹ at STP) was investigated. The nickel-containing ZrO₂, ThO₂ and UO₂ catalysts (with or without pre-reduction by hydrogen at 500°C) showed good performance in the process; the order of their performance is NiO–ThO₂>NiO–UO₂>NiO–ZrO₂. The NiO–TiO₂ showed appreciable catalytic activity only after its reduction at 800°C. However, this catalyst and the NiO–SiO₂ catalyst showed poor performance in the process. These two catalysts are also deactivated very fast, mostly because of sintering of Ni and/or formation of catalytically inactive binary metal oxide phases by solid–solid reaction at the high catalyst calcination and/or catalytic reaction temperature. Although the Ni-containing ThO₂, UO₂ and ZrO₂ catalysts showed good performance, carbon deposition on them during the process is fast. However, because of the addition of cobalt to these catalysts (with Co/Ni=1.0), the rate of carbon deposition on them in the process is drastically reduced. This Co addition however resulted in a significant decrease in both the conversion and selectivity; the decrease in the selectivity was small.     

Ni-W/SSY-Beta-Al_2O_3柴油加氢转化催化剂研究

采用SSY型分子筛、不同硅铝比Beta分子筛与大孔氢氧化铝干胶混捏制备SSY-Beta-Al_2O_3载体,等体积浸渍法制备Ni-W/SSY-Beta-Al_2O_3加氢转化催化剂,采用BET、Py-IR、XRD、NH_3-TPD对制备的催化剂及载体进行表征。在100 mL固定床加氢装置上,工业Ni-Mo型柴油加氢精制催化剂与Ni-W/SSY-Beta-Al_2O_3加氢转化催化剂级配装填,以劣质催化裂化柴油为原料,对加氢转化催化剂进行活性评价。结果表明,随着Beta分子筛硅铝比的增加,催化剂表面的L酸中心先减少后增多,B酸中心先增加后减少,催化剂的弱酸酸量先增多后减少,中强酸与强酸酸量变化不明显。在氢油体积比700∶1、反应压力8.0 MPa、精制段反应温度360℃,体积空速1.25 h^(-1),转化段反应温度400℃,体积空速1.35 h^(-1)的条件下,CYB-3催化剂加氢转化产品液相收率高达97.73%,汽油馏分收率63.72%,辛烷值91.66,柴油馏分收率33.69%,十六烷值比原料提高8.96,凝点小于-35℃。     

Pyrolysis of cellulose, xylan and lignin with the K2CO3 and ZnCl2 addition for bio-oil production

The chemical structure of liquid products of the wood biopolymers, i.e. cellulose, xylan and lignin pyrolysis at 450 °C with and without the 10 wt.% addition of potassium carbonate or zinc chloride was investigated. The yield of liquid products of pyrolysis was in the range of 24-44 wt.% and their form was depending on the chemical structure of pyrolyzed material. The potassium carbonate and zinc chloride addition to biopolymers has also influenced the temperature range of samples decomposition as well as the structure of resulted bio-oils. All bio-oils from biopolymer were dark-brown water-oil emulsions. Contrarily, bio-oils obtained from biopolymer with K₂CO₃ or ZnCl₂ addition were orange liquids with well-separated water and oil phases. All analyses proved that the composition and the quality of bio-oil strongly depends on both the nature of the starting sample and the presence of the additive. The FT-IR analyses of oils showed that oxygen functionalities and hydrocarbons contents highly depend on the type of biopolymer. Results confirmed the significant removal and/or transformation of oxygen containing organic compounds due to the zinc chloride and potassium carbonate presence during pyrolysis process.     

Conductivity of molten hydrated salts: Mg(NO3)2. 6H2O + NH4NO3 system

Conductivity of molten Mg(NO₃)₂. 6H₂O + NH₄NO₃ system containing up to 80 mole percent of the latter was measured in the temperature range 320–400 K. Temperature dependence of conductivity exhibited Arrhenian behaviour. Conductivity—composition isotherms were non-linear indicating weak ordering tendencies. Equivalent conductivity data did not obey Markov equation; deviations have been interpreted in terms of the Tobolsky parameter (θ). Constancy of θ indicate that the water of hydration in the system remains with Mg²⁺ ions and is unaffected by the addition of NH⁺₄ ions.     

Superacid coal chemistry. 2. Model compound studies under conditions of HF:BF3:H2 catalysed mild coal liquefaction

Selected model compounds representing coal structural entities were studied under the conditions of HF-BF₃-H₂ catalysed mild coal liquefaction. Bibenzyl and diphenylmethane gave near quantitative conversion at room temperature without added hydrogen. Biphenyl, however, required hydrogen pressure at 150 °C and gave a conversion of only ≈30%. Among the model compounds containing ether linkages, dibenzyl ether and benzyl phenyl ether gave quantitative conversion at room temperature without added hydrogen. Diphenyl ether in contrast was converted (≈70% yield) only under hydrogen pressure at 155 °C. Sulphur- and nitrogen-containing model compounds were also studied. At 95 °C in the absence of hydrogen, benzyl phenyl sulphide and dibenzyl sulphide gave over 95% conversion. On the other hand diphenyl sulphide and diphenyl disulphide required hydrogen pressure at 150 °C to give conversions of ≈95%. Quinoline gave a conversion of ≈20% under hydrogen pressure at 150 °C. The formation of condensation products in these conversion processes could be suppressed by the use of a good hydrogen donor, such as isopentane.     

丙烷脱氢Cr_2O_3/Al_2O_3催化剂烧焦再生过程的模型化与模拟(英文)

A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke combustion. Simulation shows that under practical operating conditions, multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas temperature. However, at increased mass flow rate or lowered oxygen concentration, multi-steady states will not appear. Under the strong influences of film diffusion, the coke in the packed bed reactor will first be exhausted at the inlet, while if the film diffusion resistance is decreased, the position of first coke exhaustion moves toward the outlet of the reactor.     

Ag-Zn_3(VO_4)_2光催化剂催化降解甲基橙溶液

采用水热法结合高温热处理制备Ag-Zn_3(VO_4)_2光催化剂,研究催化剂在可见光下降解甲基橙溶液的性能,并考察催化剂用量、甲基橙溶液初始浓度、pH值、盐效应和H_2O_2用量对光催化性能的影响,评价Ag-Zn_3(VO_4)_2光催化剂的重复使用性能。结果表明,在催化剂用量2.0 g·L~(-1)、甲基橙溶液初始浓度20 mg·L~(-1)和溶液pH=6.2条件下光照反应5 h,甲基橙溶液脱色率可达99.18%,Na_2SO_4对光催化降解甲基橙起抑制作用,且随着溶液中盐浓度增加,抑制作用更明显。H_2O_2在一定浓度范围可促进光催化降解甲基橙,100 mL甲基橙溶液中30%H_2O_2加入量为1.0 mL时,甲基橙溶液脱色率可提高21.68个百分点。催化剂重复使用5次后,光照5 h的甲基橙溶液脱色率仍可达到75.99%。