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注意:本论文已在《石油化工 》2002,31(11):871-874发表

(1.中国科学院广州能源研究所,广东广州 5l0070;2.日本东京大学,东京113-8656)


Effect of Local Heating on Hydrocracking of Heavy Oils

 CHANG Jie1, TSUBAKI Noritasu2,FUJIMOTO Kaoru 
(1.Guanghou Institute of Energy Conversion, Chiese Academy of Sciences, Guangzhou Guangdong, 510070,China 2.Department of Applied Chemistry, University of Tokyo, Tokyo 113-8656, Japan)

Petrochemical Technology 2002,31(11):871-874

Abstract: Hydrocracking tests of Canadian oil sand bitumen, Saudi Arabian heavy vacuum residue and model compound 1 -pheny1 dodecane (PhDD) were carried out in a batch autoclave reactor. The reaction conditions were as follows: pressure 5.0 MPa, temperature 410-430, reaction time 0-60 min. The heating with a fine inside filament produced small local high temperature zone in the reaction, its effect on the hydrocracking was investigated. Results show that this method accelerates the formation of free radicals, improves the conversion of heavy oil and its model compound, and increases the yield of the middle fraction oil.
Key Words: heavy oil; hydrocracking; free radical 


Elemental sulfur as an effective promoter for the catalytic hydrocracking of Arabian vacuum residue
EI village已经收录本文)

Jie Chang(常杰), Noritatsu Tsubaki, Kaoru Fujimoto 
Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo 7-3-1, Tokyo 113-8656, Japan

Abstract: The effect of element sulfur on the conversion of residue for catalytic hydrocracking of Arabian heavy vacuum residue was tested using an autoclave reactor. The reaction condition was 703K and 0.5MPa of hydrogen partial pressure. Adding only a small amount of sulfur increased the conversion of residue from 64 to 80 wt%, as well as the yield of middle distillate from 23 to 31 wt%. This should be attributed to the free-radical initiation effect of sulfur. Sulfur promoted the decomposition of residue at the catalytic hydrocracking condition.
Key Words: Sulfur; Hydrocracking; Conversion; Vacuum residue


Kinetics of resid hydrotreating reactions
注意:本论文已在《Catalysis Today》1998,43:233-239发表

Jie Chang*(常杰), Jiansheng Liu, Dadong Li
Research Institute of Petroleum Processing (PIPP) P.O. Box 914-17, Beijing, 100083, China

Abstract: Five resids from the Middle East and China have been hydrotreated in a pilot plant, which has three Æxed-bed reactors in series. Six commercial catalysts were tested. The process conditions were 12.0±16.8 MPa, 370±405, LHSVof 0.15±1.0 hˇ1, H2/oil ratio of 400±1000 nm3 mˇ3. The feedstocks included the following Chinese resids Shengli, Xinjiang and Liaohe. Kinetic parameters of resid hydrotreating reactions were calculated in terms of pore diffusion resistance and were correlated with some special properties of oils and catalysts. This study supplies important basic data for the selection of catalysts, for the design of composite catalyst beds and for the optimization of process conditions. 
Keywords: Kinetics; Reaction; Hydrotreating; Resid


(中国科学院广州能源研究所,广州 510070)

关键词:生物质 制氢  催化气化


The Promotional Effect of Initiators in Hydro-thermal Cracking of Resids
注意:本论文已在《ACS Prepr. Div. Fuel Chem., New Orleans, USA,》 44 (4), pp.801.发表

Jie Chang(常杰), Li Fan  and Kaoru Fujimoto
Department of Applied Chemistry, School of Engineering, The University of Tokyo

  With growing worldwide demand for transport fuels and other middle distillates, much attention has been paid to the upgrading of heavy oil feedstock. It was forecasted that up to early 2000, the petroleum product slate will continue to shift from fuel oil to transportation fuels, distillate and jet will be the products with the strongest growth, and the conversion will be increased worldwide to meet this trend (Sonnemans, 1995).  Based on cracking mechanism, there are three main industrial processes to produce middle distillate from resid, thermal cracking, catalytic cracking and hydrocracking. Hydro-thermal cracking, the combination of thermal cracking and catalytic hydrogenating, is a novel method developed by Fujimoto laboratory to upgrade resids aiming at maximum middle distillate (Fujimoto et al., 1988; Aimoto et al., 1991; Yang et al., 1998). The following elementary steps are important during hydro-thermal cracking reactions: (1) Initiation free radical (homolytic cleavage of a hydrocarbon molecule into two free radicals). (2) Free radical dissociation (βscission). (3) Hydrogen transfer (between H2, radical and hydrocarbon). H transfer from H2 to radical may suppress the secondary cracking of hydrocarbon. It was supposed that some effective initiators could probably enhance the conversion of resids by increasing the concentration of free radicals. Much research has been carried out on catalyst development, reaction mechanism, process design and optimization in the above refinery processes in the last half century. But the issue of adding initiators in the cracking of resids was very rarely addressed. The present work showed the promotional effect of initiators in hydro-thermal cracking of resids and its model compound.


Enhancement Effect of Free Radical Initiator on Hydro-Thermal Cracking of Heavy Oil and Model Compound
注意:本论文已在《Energy & Fuels 》13 (5), pp.1107.发表

Jie Chang(常杰), Li Fan, and Kaoru Fujimoto
Department of Applied Chemistry, School of Engineering, The University of Tokyo

ABSTRACT: The conversions of heavy oil and its model compound were remarkably enhanced by adding peroxide during hydro-thermal cracking. The reaction mechanism on model compound, n-dodecylbenzene, suggested that the hydrogen in hydrocarbon was easily abstracted by free radical formed from decomposition of peroxide and the chain reactions were readily initiated. Therefore, the conversion was obviously increased even at lower temperature.


注意:本论文已在《Sekiyu Gakkaishi (J. Japan Petrol. Inst.)》 43 (1), pp.25. 发表

Noritatsu TSUBAKI, Jie CHANG(常杰), and Kaoru FUJIMOTO
Department of Applied Chemistry, School of Engineering, The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, JAPAN

With the growing demand for high quality transportation fuels and middle distillate products, to obtain high conversion from heavy oil and bitumen is becoming the predominant research target of resid upgrading processes. Hydrothermal cracking has been developed to obtain maximum middle distillate yield (kerosene + gas oil) from residual oil [1-3]. It involves free radical chain reactions and catalytic hydrogenation reactions: (1) C-C and C-X (heteroatom) bonds rupture to produce free radicals; (2) free radical dissociation to produce low-boiling products; (3) catalytic hydrogenation to terminate radicals, remove heteroelements and saturate C-C bonds such as olefin and aromatic etc [4-5].
The decomposition of resid is thermodynamically favored at high reaction temperature. With the increase of temperature, the selectivity of by-products, coke and gaseous hydrocarbon, will be increased, and therefore the selectivity of middle distillate will be lowered. How to obtain high conversion at low reaction temperature is the key point to resolve this contradiction. According to the mechanism of free radical chain reactions, some effective initiators may enhance the conversion of residue by increasing the concentration of free radicals. The present work showed the effect of the addition of free radical initiators, di-tert-butyl-peroxide (DTBP) and sulfur, on the decomposition of resids and model compound. Both remarkably enhanced the conversion of heavy oil.


Effect of Addition of K to Ni/SiO2 and Ni/Al2O3 Catalysts on Hydrothermal Cracking of Bitumen
注意:本论文已在《Sekiyu Gakkaishi (J. Japan Petrol. Inst.) 》43 (5), pp.357. 发表

Jie CHANG(常杰), Noritatsu TSUBAKI*, and Kaoru FUJIMOTO
Department of Applied Chemistry, School of Engineering, The University of Tokyo,
Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-8656, Japan

Abstract: Hydrothermal cracking of Canadian Athabasca bitumen was performed over Ni/SiO2 and Ni/Al2O3 catalysts under 703 K and 5.0 MPa of hydrogen pressure in a batch reactor. Comparing with thermal cracking under the same reaction conditions, hydrothermal cracking process obviously suppressed the formation of coke from 5.5wt% to 3.5wt% (Ni/SiO2) and to 3.0wt% (Ni/Al2O3), and the formation of gaseous hydrocarbon products. To decrease coke formation further, a small amount of potassium was impregnated in the catalysts. The spectroscopy of NH3-TPD showed that the amount of acidic sites in both catalysts, Ni/Al2O3 and Ni/SiO2, was dramatically decreased by K2O modification. The acid-catalyzed polymerization of residuum induced by acidic sites in the catalyst, that might result in the formation of coke, was suppressed by neutralization of the acidic sites. Adding 3% of potassium onto Ni/SiO2 decreased the yield of coke from 3.5wt% to 2.1wt%.
Keywords: Hydrothermal process, Catalyst modification, Acidity, TPD


Initiation Effect of Local Heating in Hydro-Thermal Cracking of Resids
注意:本论文已在《Energy & Fuels 》14 (6), pp.1331. 发表

Jie Chang(常杰), Noritatsu Tsubaki* and Kaoru Fujimoto
Department of Applied Chemistry, School of Engineering, The University of Tokyo,

Masao Yoshimoto Petroleum Energy Center of Japan, KSP R&D Build. D-12-1237, 3-2-1, Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan 

    The upgrading of heavy oils is attracting growing interest as a means of producing premium quality transportation fuels and other middle distillate products. Hydro-thermal cracking is one of the promising processes to obtain maximum middle distillate (kerosene + gas oil) from residual oils. This process and its reaction mechanism have been described elsewhere.1,2 Hydro-thermal cracking of resid, which is the combination of thermal cracking and catalytic hydrogenation, is composed of the following elementary steps: (1) formation of free radicals proceeding via cleavage of C-C or C-X (heteroatom) bond;3,4 (2) production of middle distillate proceeding via β-scission of free radicals;5 (3) termination of free radical reactions and saturation of C=C bonds proceeding via catalytic hydrogenation.
     High reaction temperature can simply accelerate the conversion of resid, but the selectivities of gaseous hydrocarbons and coke will be increased tremendously. We have demonstrated that adding some initiators, such as element sulfur and di- tert-butyl-peroxide, which might produce free radicals even at lower temperature, promoted the conversion of resids and increased the yield of distillate.2,6 This paper presents our results on another initiation method, local heating by inside filament. The in situ measurement of free radical concentration during hydro-thermal cracking of Kuwait AR was carried out by ESR and reported elsewhere.7 The in situ spin concentration (at g = 2.0035, which shows the signal of hydrocarbon free radical) was detected by using a quartz tube containing Kuwait AR at 2.0 MPa of hydrogen pressure and heating it at 5 K/min. The results showed that the spin concentration of free radicals increased with the increasing temperature probably due to the cleavage of C-C and C-S bond and leveled off at about 480 K, then it slightly decreased, and again increased very quickly at above 680 K. According to this trend, an inside filament was employed to realize higher-temperature zone at some limited space inside the reactor to initiate the formation of free radicals at lower reaction temperature. The experiment results proved that local heating effectively promoted the conversion of Canadian oil sand bitumen and Arabian VR.


Enhancing Effect of Local Heating by an Inside Filament on Hydrothermal Cracking of Hydrocarbon Catalyzed by Ni/Al2O3

注意:本论文已在《Sekiyu Gakkaishi (J. Japan Petrol. Inst.) 》 43 (6), pp. 414. 发表

Jie CHANG†1)(常杰), Noritatsu TSUBAKI†1)*, Kaoru FUJIMOTO†1) and Masao YOSHIMOTO†2)
†1) Dept. of Applied Chemistry, School of Engineering, The University of Tokyo,
Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-8656, JAPAN
†2) Petroleum Energy Center of Japan, KSP R&D Build. D-12-1237, 3-2-1, Sakado,
Takatsu-ku, Kawasaki, Kanagawa, 213-0012, JAPAN

    During the hydrothermal cracking of hydrocarbon and heavy oil catalyzed by Ni/Al2O3, the conversions of hydrocarbon and heavy oil were remarkably enhanced by heating with a small inside filament. The experiment facts suggested that the heating with inside filament might realize higher temperature zone at local space in the reactor, which was responsible for an increase of the concentration of free radicals, and enhanced the conversion of hydrocarbons even at lower temperature.
Keywords: Hydrothermal process, Hydrocarbon, Heavy oil, Initiation, Filament

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