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.     

Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene

The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2-methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low concentrations of diphenylmethane were detected at the highest temperature. This indicates that the opening of the phenyl? CH₂ bond in fluorene is much faster than the splitting of the phenyl—phenyl bond. The splitting of the phenyl—phenyl bond in biphenyl, however, proceeded with a rate equal to the splitting of the phenyl? CH₂ bond in fluorene and the phenyl? CH₃ bond in 2-methylbiphenyl.     

煤焦油加氢裂化反应及其催化剂的研究

以煤焦油为原料,研究加氢裂化反应类型及反应产物油馏分的调制机理。以γ-Al2O3为载体,Mo、Ni为加氢活性组分,采用分步浸渍法制备负载型MoO3-NiO/γ-Al2O3加氢裂化催化剂。在高压反应釜上考察反应压力、反应温度对煤焦油加氢催化裂化反应的影响,比较了3种不同NiO质量分数的催化剂加氢活性,实验结果表明,NiO质量分数为3.68%的催化剂活性最好,并获得了低硫、低氮、低芳烃的反应产物油。     

Prediction of TMCH thermal hazard with various calorimetric tests by green thermal analysis technology

1,1,‐Di‐(tert‐butylperoxy)‐3,3,5‐trimethylcyclohexane (TMCH), a liquid organic peroxide, has been widely used in the chemical industry as a polymerization initiator. The thermokinetic parameters of TMCH are investigated by three types of calorimetric tests (isothermal, nonisothermal, and adiabatic) to determine thermal decomposition properties of TMCH using differential scanning calorimetry (DSC) isothermal tests, DSC nonisothermal tests, and vent sizing package 2 adiabatic tests, respectively. Comparisons of three kinds of thermal analysis models were done for kinetics simulation, which can result in a beneficial kinetic model and parameters of thermal decomposition of TMCH. The use of green technology to replace the complex methods and energy consumption of the traditional self‐accelerating decomposition temperature tests are discussed. There are significant disadvantages with traditional thermal analysis methods in terms of a novel, swift, and green technology, which is the achieved object here for preventing pollution and reducing energy consumption. © 2012 American Institute of Chemical Engineers AIChE J,, 2012     

高温煤焦油悬浮床加氢裂化研究

利用悬浮床加氢对高温煤焦油进行加氢裂化研究。分析了煤焦油的性质,研究了反应条件对产物分布的影响。结果表明,随着温度的升高和时间的延长,反应裂解程度加深,反应生成更多的气体、石脑油和柴油馏分,同时甲苯不溶物的含量也在增高。反应压力低于15MPa,提高压力,汽柴油馏分产率提高显著,反应高于15MPa汽柴油产率提高不明显,甲苯不溶物含量显著提高。     

USY分子筛扩孔对低温煤焦油加氢裂化的影响

以NH4F溶液、NH4F和HF混合液处理USY分子筛,制备加氢裂化催化剂。通过BET、XRD表征催化剂的比表面积、孔容孔径及晶体结构,在340℃,5.0MPa,空速3.0h-1以及氢油体积比为600条件下,使用改性后催化剂对低温煤焦油进行加氢裂化反应,评价催化剂的催化效果。结果表明,处理后的载体制备的催化剂不但没有完全破坏分子筛固有结构,而且平均孔径有很大的提高,出现二次孔,在催化剂效果评价中,以NH4F和HF混合液处理得到的催化剂由于维持了催化剂的酸性,其催化效果远好于空白USY系列和NH4F溶液系列催化剂。     

催化剂制备与研究 中低温煤焦油加氢裂化催化剂的表征与分析

通过对反应前后的煤焦油加氢裂化催化剂进行表征与分析,研究影响中低温煤焦油加氢催化剂失活的原因,以煤焦油组分特点为依据,分别考察加氢裂化催化剂的活性元素、积炭、金属沉淀、分散度和中心酸性等对催化剂寿命的影响。结果表明,煤焦油加氢催化剂的失活原因主要为积炭失活、金属沉积和水热失活;催化剂中较低的金属钙含量、良好的水热稳定性及较低的L酸含量有利于催化剂寿命的提高。     

F-T合成加氢裂化催化剂的工业应用

F-T合成油低温工艺产物中有大于质量分数40%的石蜡生成,必须对其进行加氢裂化生产优质的中间馏分油。加氢裂化关键在于高性能催化剂的研究开发,概述了近年来加氢裂化催化剂在国内外的应用现状。FC-14及SC-I催化剂在内蒙古伊泰煤制油有限责任公司的运行结果表明,SC-I催化剂表现出良好的活性及较高的中间馏分油选择性,在总进料20 t·h^-1、反应器入口氢分压7.0 MPa、氢油体积比800和总体积空速（2.0~15.0） h^-1条件下,反应器出口温度约340 ℃,总温升14 ℃,表现出较高的反应活性及灵活的温度调控性,柴油收率上升约3~4个百分点,具有较高的中油选择性。     

Hydrocracking of a coal extract with various catalysts

Catalytic hydrogenations using a number of bimetallic and monometallic catalysts were performed in an autoclave fitted with a falling/spinning catalyst basket. The catalysts were used as oxides with and without the addition of carbon disulphide to the autoclave charge. The products were separated by vacuum distillation and the performance of the catalysts was assessed by combining the yields from vacuum distillation with the peak area distribution of the gas chromatographs of the distillation fractions. The presence of carbon disulphide reduced the yield of material boiling below 260 °C and was particularly effective in reducing the yield of material boiling below 175 °C. Bimetallic catalysts which included molybdenum as one component generally performed better than similar bimetallic catalysts which included tungsten as one component and better than monometallic catalysts. Commercial CoMo performed well both with and without added carbon disulphide but commercial NiMo was inferior to most other catalysts when carbon disulphide was not added and to many when carbon disulphide was added. The sulphur content of the liquid products was not significantly affected by the addition of carbon disulphide to the charge.     

Determining the clinkering properties of coal by means of various plastometric systems

Various methods are compared for determining the clinkering properties of coal, with different plastometric systems. Operating conditions are proposed for the AP5 automated plastometer.     

一氯甲烷高压热氯化反应相态分析

通过对一氯甲烷高压热氯化的临界参数及相关数据的计算,对反应的相态进行了分析 并得出结论。     

Effects of pressure in coal pyrolysis observed by high pressure TGA

High-pressure thermogravimetric analyzer was employed to investigate the effects of pressure on the thermal decomposition process, which is the very first step in most coal utilizing processes, and pyrolyzates from TGA were analyzed by on-line GC/MS. Results showed that pyrolysis of coal with steam under high-pressure conditions exhibited a slower reaction rate compared to the lower pressure conditions, and the effect is more evident at the high temperature region. Coal rank also exhibited a distinct effect on the pyrolysis rate such that a subbituminous coal showed a bigger effect by steam-addition and pressure than bituminous coals. Weathered coal sample illustrated a slower reaction rate compared to the unoxidized coal. In addition, the implication of pressure effects on pyrolysis has been described.     

柴油加氢裂化装置加氢裂化催化剂失活分析

在某炼油厂柴油加氢裂化装置停工换剂时,取样分析加氢裂化催化剂。对所取裂化剂进行甲苯抽提、再生后,采用比表面积及孔径分析仪、碳硫分析仪(C-S)和X射线衍射仪(XRD)等手段进行检测。结果表明,失活裂化剂的比表面积、孔容等孔结构性能参数明显降低。在最优的再生条件下,再生裂化剂上的C含量降至0.360%,裂化剂的表面或其它位置未发现杂质的明显沉积。再生裂化剂的比表面积损失约21.5%,其中微孔比表面积的损失约占87.2%,孔容损失约17.4%。加氢裂化催化剂长期在高温等条件下反应,造成分子筛晶粒的烧结、团聚等是导致其比表面积等孔结构性能降低的主要原因。     

Development and reactivity tests of Ce-Zr-based Claus catalysts for coal gas cleanup

Claus reaction (2H₂S + SO₂ ↔ 3/nS_n + 2H₂O) was used to clean the gasified coal gas and the reactivity of several metal oxide-based catalysts on Claus reaction was investigated at various operating conditions. In order to convert H₂S contained in the gasified coal gas to elemental sulfur during Claus reaction, the catalysts having the high activity under the highly reducing condition with the moisture should be developed. CeO₂, ZrO₂, and Ce_1−xZr_xO₂ catalysts were prepared for Claus reaction and their reactivity changes due to the existence of the reducing gases and H₂O in the fuel gas was investigated in this study. The Ce-based catalysts shows that their activity was deteriorated by the reduction of the catalyst due to the reducing gases at higher than 220 °C. Meanwhile, the effect of the reducing gases on the catalytic activity was not considerable at low temperature. The activities of all three catalysts were degraded on the condition that the moisture existed in the test gas. Specifically, the Ce-based catalysts were remarkably deactivated by their sulfation. The Ce-Zr-based catalyst had a high catalytic activity when the reducing gases and the moisture co-existed in the simulated fuel gas. The deactivation of the Ce-Zr-based catalyst was not observed in this study. The lattice oxygen of the Ce-based catalyst was used for the oxidation of H₂S and the lattice oxygen vacancy on the catalyst was contributed to the reduction of SO₂. ZrO₂ added to the Ce-Zr-based catalyst improved the redox properties of the catalyst in Claus reaction by increasing the mobility of the lattice oxygen of CeO₂.     

Storage of small samples of coking coal for thermal rheological tests

A study was undertaken with the aim of finding the best practical way of storing small coal samples in a laboratory setting to limit their extent of oxidation for maintaining good thermal rheological properties. Samples of a Canadian medium-volatile bituminous coal of Cretaceous age (‘as received’ and < 0.42 mm sizes) were stored under various media (open trays in laboratory, in an oven, under water and under vacuum) and temperatures (− 15, 4, 20 and 40 °C) for up to 60 weeks. Samples were analyzed for Chemical changes including O content, O / C, H / O, H / C, Volatile Matter, and Calorific Value; Thermal Rheological changes in Fluidity, Plastic range, Dilatation, Free-Swelling Index and Alkali Light Transmittance. Coke Quality changes in Coke Cake Contraction, Coke Reactivity and Coke Strength indices as well as Coke Optical Textures were also examined. For chemistry related changes, the most obvious ones due to oxidation are in atomic oxygen, which increases, and calorific value, which decreases. Concerning thermal rheology changes, fluidity and dilatation were found to decrease the most whereas Free-Swelling Index and Alkali Light Transmittance do not appear to be sensitive indicators of early stages of oxidation for the examined coal. Pertaining to coke quality, coke cake contraction remains essentially unchanged, Coke Strength after Reaction decreases and Coke Reactivity Index increases, and textures reveal a significant increase in coke inerts.This work has found coal oxidation to be mainly influenced by the storage temperature, with rate of oxidation increasing with temperature, and to a lesser extent by particle size, with oxidation being more likely the smaller the particle size.Of the different storage conditions tested in this investigation, keeping coal at cold temperatures (< − 15 °C) was found to be the most favourable for limiting its oxidation and thereby maintaining good thermal rheological properties.     

Recycling polystyrene into fuels by means of FCC: performance of various acidic catalysts

In accordance with the option of recycling plastics into fuels by dissolving them in standard feedstocks for the process of catalytic cracking of hydrocarbons, FCC, various acidic catalysts (zeolites ZSM-5, mordenite, Y, and a sulfur-promoted zirconia) were tested in the conversion of polystyrene dissolved into inert benzene at 550°C in a fluidized-bed batch reactor. Experiments were performed with very short contact times of up to 12 s. Main products were in the gasoline range, including benzene, toluene, ethylbenzene, styrene, and minor amounts of C_9–12 aromatics and light C₅₋ compounds. Coke was always produced in very significant amounts. All the products can be justified with basis on the properties of each catalyst and the various possible catalytic reaction pathways: cracking after protolytic attack on the polymer fragments, styrene oligomerization and subsequent cracking, or hydrogen transfer to styrene. Styrene would be mainly produced in this system from thermal cracking of the polymer as the initial step. If present, shape selectivity effects due to catalyst structure can influence significantly the prevalence of the various reactions, because they would interfere with those undergoing bulky transition states, like styrene oligomerization or hydrogen transfer. Even though sulfur-promoted zirconia is highly acidic, the low proportion of Brønsted-type acid sites does not allow the occurrence of secondary styrene reactions. It was shown that most favorable product distributions (higher yields of desirable products) are obtained on equilibrium commercial FCC catalysts.     

Green tea encapsulation by means of high pressure antisolvent coprecipitation

In this work, green tea polyphenols were coprecipitated with a biodegradable polymer (poly-?-caprolactone, MW: 25,000) by a semi continuous supercritical antisolvent process (SAS). Carbon dioxide was used as antisolvent in addition to be a dispersing agent. Green tea extracts were obtained by microwaved assisted extraction (MAE) technique with acetone. The influence of different process parameters, including the operating pressure (8-12 MPa) and temperature (283-307 K), the polymer to solutes concentration (w/w) ratio (4-58), and the CO₂ to solution mass flow rate ratio (4-10) have been studied experimentally. Total content of polyphenols, quantified according to the Folin-Cicalteu method, showed concentrations from 60 to 100% of the maximum theoretical composition. Also HPLC analyses were performed to verify the presence of some of the major tea catechins. SEM images of the products show small particles (3-5 μm) with narrow particle size distribution with a high degree of agglomeration. Drug release profiles in phosphate buffer (pH = 6.8) reveal that the majority of catechins are encapsulated in the crystalline domains of the polymer.     

Triglyceride composition of lard by differential thermal analysis

The differential thermal analysis of lard is described and an attempt is made to assign the melting peaks to particular triglycerides which are likely to be found in lard.     

Pyrolysis oil upgrading by high pressure thermal treatment

High pressure thermal treatment (HPTT) is a new process developed by BTG and University of Twente with the potential to economically reduce the oxygen and water content of oil obtained by fast pyrolysis (pyrolysis oil), properties that currently complicate its co-processing in standard refineries. During the HPTT process, pyrolysis oil undergoes a phase split yielding a gas phase, an aqueous phase and an oil phase. In this study, HPTT experiments were carried out at different operating conditions in a continuous tubular reactor. Experimental results showed that, with increasing temperature and residence time, the release of gases (mainly CO₂) and the production of water increased, reducing the oxygen content of the oil phase and hence increasing the energy content (from 14.1 to 28.4 MJ/kg) having the temperature a larger effect when compared to the residence time. Using gel permeation chromatography (GPC), an increase of the molecular weight of the oil phase, probably due to polymerisation of the sugars present in pyrolysis oil, was observed. When water was added as solvent to dilute the feed oil, a decrease of the molecular weight of the resulting oil phase was observed. This indicated that the concentration of organic components had a direct effect on the formation of high molecular weight components. In conclusion, during HPTT an oil with lower oxygen and water content with higher energy value was produced, but adverse formation of high molecular weight components was also detected.