Catalytic Reforming Catalysts and Technology in China

Catalytic reforming is an important means for producing high-octane gasolinecomponent and aromatics from naphtha feedstock while providing a hefty amount of cheap hydrogen torefineries. Catalytic reforming, as one of the important processes needed by global refineries andpetrochemical plants, has become the focus of attention. In order to tackle the global environmentalprotection issues, every country has promulgated new gasoline standard. The reformer gasoline hasbeen regarded as the most ideal blending component for the reformulated gasoline thanks to its highoctane number, low olefin content and nearly zero sulfur content. The share of reformer gasolineaccounts for less than 10% of total gasoline pool marketed in China, while this share in thedeveloped countries of North America and Europe reaches 30%—38%. Hence increasing the ratio ofreformate blending component in gasoline pool should be the main instrument for improving thequality of clean gasoline in China. Large amount of hydrogen, as the co-product of catalyticreforming, can be used to improve the quality of petroleum products, develop hydrogenation process,reduce the olefin and sulfur contents in oil products, and provide a spate of cheap hydrogen sourcesto save large investment in construction of hydrogen plants and operating cost. Thus the role ofcatalytic reforming is increasingly capturing the attention of people in China. As China currentlyis faced with an urgent shortage of catalytic reforming capacity, catalytic reforming units in Chinawill have large development potentials as compared to the situation of catalytic reforming in thedeveloped countries of North America and Europe. China began to engage in the R&D work on catalyticreforming since the mid 1950s. In 1965 a 100kt/a semi-regenerative catalytic reforming unit, theR&D, design and construction of which were implemented by Chinese engineers and workers themselves,was put on stream successfully at Daqing refinery, which had operated on the first domesticallymanufactured Pt/γ-Al_2O_3 reforming catalyst (commercial catalyst grade designation: 3641).Afterwards a series of bimetallic and multimetallic semi-regenerative reforming catalysts andcontinuous catalytic reforming (CCR) catalysts have been developed and widely applied. In themeantime, the catalytic reforming process in China has been developing with a spi-raling rate. As ofMarch 31, 2003 forty-seven semi-regenerative reforming units with a total processing capacity of9.935 Mt/a had been put on stream in China, whereas 18 CCR units with a total capacity of 11.54 Mt/ahad been put into operation. The status of development of catalytic reforming in China is presentedin Table 1.

A MODIFIED FCC PROCESS FOR MAXIMIZING ISOPARAFFINS (MIP) IN CRACKED NAPHTHA

A concept of two different reaction zones was proposed based on the FCC reaction mechanism. The concept was used to design a novel reactor with corresponding operation measures. Experiments were conducted on the newly designed pilot plant riser reactor. In comparison with the conventional FCC at relatively equivalent conversion, the pilot plant test results showed that the olefin content in the cracked naphtha dropped by 12.4%, and both contents of iso paraffin and aromatic increased by 6%, and its MON increased by 1.3 units while maintaining the RON of the naphtha unchanged, and its sulfur content reduced by 15% with a significant extension of its induction period for Shengli VGO+VR. The run test results of commercial trial were conformable with the results of pilot plant test.

Commercial Practice on Technology for High-Temperature Cracking of C_4 Fraction to Increase Propylene Yield

This article refers to the results of small-scale and commercial tests on high-temperature cracking of C4 fraction in FCC unit to increase the propylene yield. The bench tests revealed that the conversion rate of C4 fraction during high-temperature cracking reached 37.38 % and propylene yield was equal to 15.60 % with the conversion rate of C4 olefins equating around 50%. The results of commercial application showed that adoption of the technology for high-temperature cracking of C4 fraction in FCC unit had led to an increase of propylene yield by 2.16 % with no remarkable changes in the yields and properties of other products.

Alkylation of Isobutane and Butene on BrФnsted-Lewis Conjugated Solid Superacids

A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 wassynthesized by a two-step method. This B-L acid shows high acid strength, high activity, goodselectivity and moderate stability in alkylation of isobutane/butene due to strong interactionbetween the BrOnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Undera mild reaction condition (30℃, 15-35xl0~5 Pa), the conversion of butene was maintained at 100% for110 hours on stream and the main products were C_8 and TMP. The results of alkylation conductedunder various operating conditions indicated that the activity was improved by increasing theloading content of HPW and SbF_5. The selectivity of TMP in the products was enhanced when theisobutane/butene ratio in the feedstock was increased. The existence of some intermediates was alsoreported.

FCC Study of Canadian Heavy Gas Oils—Comparisons of Product Yields and Qualities between Reactors

Several series of cracking tests in a comprehensive study were conducted on separate occasions involving all or parts of ten Canadian vacuum gas oils (VGOs) and two catalysts with bottoms-cracking or octane-barrel capability. VGOs were cracked in fixed- and/or fluid-bed microactivity test (MAT) units, in an Advanced Cracking Evaluation (ACE) unit, and in a modified ARCO riser reactor. Individual yields of gas, liquid, and coke from the MATs at 55, 65, 70, and 81 wt% conversion levels were compared with their respective pilot plant data. Good linear correlations could be established between MAT and riser yields except for liquefied petroleum gas (LPG) and light cycle oil (LCO). At a given conversion, correlations existed among the fixed- and fluid-bed MAT units and the ACE for each product yield. Liquid products from the fixed or fluid-bed MAT were analyzed for hydrocarbon types, sulfur, nitrogen and density, most of which showed good agreement with those obtained from the riser study. When cracking Canadian oil-sands-derived VGOs, the bottoms-cracking catalyst containing a large-pore active matrix was found to be more suitable than the octane-barrel catalyst with smaller pores to produce higher yields of valuable distillates, but with less superior qualities (in terms of sulfur and nitrogen contents). The advantages of hydrotreating some poor feeds to improve product yields and qualities were demonstrated and discussed.

A SAPO-11 Silicoaluminophosphate Molecular Sieve with Stable Crystal Structure

A SAPO-11 silicoaluminophosphate molecular sieve with stable crystal structure was synthesized for the first time. After removing template by calcination, its crystal space group still retains Icm2 which the as-synthesized has. The catalyst deriving from the present SAPO-11 materials shows higher isomerization selectivity and higher paraffin hydroisomerization yield than those reported elsewhere.

Study of Coked Commercial FCC Catalysts by a Novel Micro-Reactor GC System and Its Characterization by ^(129)Xe NMR

A novel Micro-Reactor-GC system was used to study the performance of two kinds of FCC catalysts coked in a FFB reactor under simulated industrial conditions using dodecane and octene as probe molecules. The result shows that the performance of the two cokedcatalysts differed significantly. The 129Xe NMR technique was used to detect the location of coke deposition on the catalysts, which gave a good explanation of the experimental results.

Commercial Application of RMC Technology in the 1.5 Mt/a Hydrocracking Unit at Shanghai Petrochemical Company

The RMC technology developed by RIPP has been applied in a 1.5 Mt/a medium pressure hydrocracking unit at Shanghai Petrochemical Company. The unit was successfully put on stream in September 2002. Calibration of the performance of the commercial unit has shown that the RMC technology has higher hydrogenation activity and selectivity, and high quality product can be obtained under lower reaction temperature. The heavy naphtha with less than 0.5 ppm of sulfur and 58.5 m% potential aromatic content is a good feedstock for catalytic reforming unit. The diesel with less than 0.5 ppm of sulfur, 6.6 m% aromatics and cetane rating of 56 is a high-grade diesel fuel. The hydrocracked tail oil containing more than 14 m% hydrogen and mere 1.7m% aromatics could be used as a good feedstock for steam cracking process to produce ethylene.

Manufacture of High-Quality Bright Stock and Ultra-Viscous White Oil from Xinjiang Heavy Naphthenic Crude Oil

Using a three-stage hydrogenation process, high-quality 150 bright stock (150BS) was produced from light DAO (LDAO, light deasphalted oil), which was obtained from vacuum residue of heavy naphthenic crude oil of Zone No.9 in Xinjiang. The 150BS product, whose viscosity index is greater than 90, is colorless and has good viscosity-temperature characteristics. This product turns out to be an excellent blending component of high-grade engine oil. And with the 150BS as a feed, very high-viscosity white oil was also produced by a further hydrofining step to substantially reduce the amount of polyaromatics contained in the feed.

Ethylene Polymerization Catalyzed by Monocyclopentadienyl Titanium Complex Containing 8-Quinolinolato Ligand and ADF Study on the Formation Mechanism of Active Species

A monocyclopentadienyl titanium complex containing 8-quinolinolato (QCpTiCl_2) was synthesized. Its activities in ethylene polymerization at various Al/Ti molar ratios, different temperatures and activation time were investigated. The activity with a Al/Ti molar ratio of 500 exhibited a maximum of 2.8×10~5 g/(mol.h) at 30℃. The activation time of QCpTiCl_2 with MAO before polymerization also plays a role on the activity. The structural properties of the produced polyethylene (molecular weight, molecular weight distribution and melting point) were discussed. Kinetic behaviors of ethylene polymerization with the QCpTiCl_2/MAO system at different Al/Ti molar ratios were studied. For the QCpTiMeCl/MAO system and the CpTiMe_2Cl/MAO system, binding energies of the examined intermediates were calculated by quantum-mechanical method based on ADF program, respectively. It is confirmed that the chlorinebridged adduct formed by the reaction of QCpTiMeCl with MAO is thermodynamically steady. In the case of the QCpTiMeCl/MAO system, olefin-separated ion pair (OSIP) mechanism is much favorable than ion-pair dissociation (IPD) mechanism. The experimental result on the CpTiMe_2Cl/MAO system showed lower activity for ethylene polymerization than that on the QCpTiMeCl/MAO system, which revealed that the CpTiMe_2Cl/MAO system is unfavorable to form active species with ethylene.

MGD Technology Development and Its Commerial Application

MGD，a FCC technology that can maximize both the LPG and LCO production,has been developed,The effects of reaction temperature and catalyst to oil ration on naphtha re-craking and the resulted naphtha ompositions were investigated ,The commercial performances show that relative to conventional FCC,the LPG and LCO yields increased by 1.3%-5.0m% and 3%-5m%,respectively. Olefins content in naplhtha decreased by 9%-13v% ,RON and MON of naphtha increased by 0.4-0.7 and 0.4-0.9 units ,respectively.

Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

Amorphous nickel based alloy catalysts (denoted as the SRNAseries catalysts) were prepared viarapid quenching method followed by alkali leaching and other activation procedures. The physicochemicalcharacterizations show that nickel, the active component in these catalysts, exists in the amorphous state, andthe catalyst particles possess many nanosized voids leading to large surface area (the highest is 145m2/g). Theevaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higheractivity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups. At present, the SRNA series catalysts have been successfully used in hydrogenation ofglucose, hydrogenation of pharmaceutical intermediates and purification of caprolactam. In order to use thesecatalysts efficiently, a magnetically stabilized bed (MSB) technology has been developed by combining theferromagnetic property of the catalyst with the good mass transfer characteristics of MSB. The demonstrationunit of MSB hydrogenation technology has been set up and has kept running for 2800 hours. The results showthat, after running 2800 hours, the catalyst still retained good activity; meanwhile, the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

Skeletal Isomerization and Inter—molecular Hydrogen Transfer Reactions in Catalytic Cracking

Bimolecular hydrogen transfer and skeletal isomerization are the important secondary reac tions among catalytic cracking reactions, which affect product yield distribution and product quality.Catalyst properties and operating parameters have great impact on bimolecular hydrogen transfer and skeletal isomerization reactions. Bimolecular hydrogen transfer activity and skeletal isomerization activity of USY-containing catalysts are higher than that of ZSM-5-containing catalyst. Coke deposition on the active sites of catalyst may suppress bimolecular hydrogen transfer activity and skeletal isomerization activity of catalyst in different degrees. Short reaction time causes a decrease of hydrogen trans fer reaction, but an increase of skeletal isomerization reaction compared to cracking reaction in catalytic cracking process.

Studies on the Reaction Mechanism of CPP and the Factors Affecting the Yields of Ethylene and Propylene

The reaction mechanisms of Catalytic Pyrolysis Process and theethylene and propylene forma-tion reaction are analyzed, and ethylene and propylene are produced through both the free radical reac-tion and carbenium ion reaction. The factors affecting the yields of ethylene and propylene are discussed.The results showed that greater yields of ethylene and propylene can be obtained on ZSM-5 catalystsrather than USY and REY catalysts, and the modified ZSM-5 could improve the ethylene yield. A highertemperature is favorable for enhancement of the free radical reaction as opposed to carbenium ion reaction,and change in temperature can adjust the ratio of ethylene and propylene production. A higher steamamount could produce more ethylene and propylene and less coke, and lowering the catalyst/oil ratio isfavorable for producing ethylene.

Study and Pilot Scale Development of Catalyst for Ethylebenzene Synthesis THrough Transalkylation of Benzene and Polyethylbenzene

This paper refers to the results of study and development of benzene and polyethylbenzene transalkylation catalyst (type AEB-1) for synthesis of ethylbenzene. The effect of reaction conditions on the reaction performance of the catalyst was investigated in the pressurized microreactor CDS-900. A transalkylation catalyst with high activity, good selectivity and stability was developed following a 2000-hour test on the activity and stability of the catalyst. The preparation of this catalyst was implemented in pilot scale and this catalyst was tested for activity and stability in a 150 t/a pilot unit for production of ethylbenzene. The test results have shown that this transalkylation catalyst has excellent activity, selectivity and stability. The operation of pilot test unit ran smoothly and the process scheme is viable.

Study on Aromatization of C_6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

Technical Development and Commercial Application of PAF—02 Antifoamer for Propane Deasphalting Unit

On the basis of fundamental research on the foaming and antifoaming mechanism in propane deasphalting units, the preparation and the simulated performance evaluation of seven antifoaming agents were conducted in the laboratory scale. The test results showed that the complex silicone antifoamer dis played better performance than other additives in both antifoaming and foam breaking. The results of commercial application also support the fact that foaming problems in the strippers of the deasphalting unit can be effectively suppressed by PAF-02 antifoamer. Successful foaming control has improved the operation efficiency of the stripper along with increasing its processing capacity. Application of the PAF-02 antifoamer has shown no negative impact on the downstream operation or product quality. Adoption of the PAF-02 antifoamer has revealed the advantages of ease in application, lower operating cost, and high antifoaming performance.

Influence of Yttrium and Ytterbium on Reaction Performance of Platinum－Rhenium Reforming Catalyst

The influence of yttrium and ytterbium on the catalyticperformance of Pt-Re reforming cata-lysts was studied in a continuous flow pressurized microreactor-chromatograph system and pilot unit. Theresults of micro-reactor test showed that both yttrium and ytterbium could improve the selectivity of Pt-Recatalysts for the conversion ofn-heptane as well as MCP into aromatics, but also suppressed their activityas well. Pilot test results showed that yttrium and ytterbium enhanced both the selectivity and activity ofPt-Re catalysts for naphtha reforming. Yttrium showed more improvement than ytterbium. The perfor-mance difference between microreactor test and pilot test might be due to the difference in improvement ofcatalytic stability of yttrium or ytterbium modified Pt-Re catalysts. Yttrium and ytterbium improved thecoking resistance of yttrium or ytterbium modified Pt-Re catalysts. TEM determination results indicatedthat both yttrium and ytterbium had improved the thermal stability of Pt-Re catalysts.