Fischer-Tropsch wax catalytic cracking for the production of low olefin and high octane number gasoline: Process optimization and heat effect calculation

To produce low olefin gasoline with high octane number by Fischer-Tropsch (F-T) wax fluid catalytic cracking (FCC) process, operating conditions optimization were carried out in the pilot-scale riser and turbulent fluidized bed (TFB) FCC unit. The experimental results in the riser indicated that under the condition of low reaction temperature and regenerated catalyst temperature, large catalyst-to-oil weight ratio (C/O) and long reaction time, the gasoline olefin content could be reduced to 20.28 wt%, but there is large octane number loss owing to a great loss in high octane number olefin. Therefore, a novel FCC process using the TFB reactor was proposed to strengthen the aromatization reaction. The reaction performance of TFB reactor were investigated. The result demonstrated that the TFB reactor has more significant effect in reducing olefins and improving aromatics. At the expense of certain gasoline yield, the gasoline olefin content reduced to 23.70 wt%, aromatics content could increase to 26.79 wt% and the RON was up to 91.0. The comparison of reactor structure and fluidization demonstrated that the TFB reactor has higher catalyst bed density. The reaction heat and coke combustion heat was calculated indicating the feasibility of its industrial application of the TFB process.

Secondary Cracking of Gasoline and Diesel from Heavy Oil Catalytic Pyrolysis

This paper investigated the secondary cracking of gasoline and diesel from the catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 in a fluidized bed reactor.The results show that the secondary cracking reactivity of gasoline and diesel is poor,and the yield of total light olefins is only about 10%(by mass).As reaction temperature increases,ethylene yield increases,butylene yield decreases,and propylene yield shows a maximum.The optimal reaction temperature is about 670℃for the production of light olefins.With the enhance- ment of catalyst-to-oil mass ratio and steam-to-oil mass ratio,the yields of light olefins increase to some extent. About 6.30%of the mass of total aromatic rings is converted by secondary cracking,indicating that aromatic hy- drocarbons are not easy to undergo ring-opening reactions under the present experimental conditions.

Enhancing hydrothermal stability of nano-sized HZSM-5 zeolite by phosphorus modification for olefin catalytic cracking of full-range FCC gasoline

In this study, phosphorus modification by trimethyl phosphate impregnation was employed to enhance the hydrothermal stability of nano‐sized HZSM‐5 zeolites. A parallel modification was studied by ammonium dihydrogen phosphate impregnation. The modified zeolites were subjected to steam treatment at 800 °C for 4 h (100% steam) and employed as catalysts for olefin catalyticcracking (OCC) of full‐range fluid catalytic cracking (FCC) gasoline. X‐ray diffraction, N2 physicaladsorption and NH3 temperature‐programmed desorption analysis indicated that, although significantimprovements to the hydrothermal stability of nano‐sized HZSM‐5 zeolites can be observedwhen adopting both phosphorus modification strategies, impregnation with trimethyl phosphatedisplays further enhancement of the hydrothermal stability. This is because higher structural crystallinityis retained, larger specific surface areas/micropore volumes form, and there are greaternumbers of surface acid sites. Reaction experiments conducted using a fixed‐bed micro‐reactor(catalyst/oil ratio = 4, time on stream = 4 s) showed OCC of full‐range FCC gasoline-under a fluidized‐bed reaction mode configuration-to be a viable solution for the olefin problem of FCC gasoline.This reaction significantly decreased the olefin content in the full‐range FCC gasoline feed, andspecifically heavy‐end olefins, by converting the olefins into value‐added C2–C4 olefins and aromatics.At the same time, sulfide content of the gasoline decreased via a non‐hydrodesulfurization process.Nano‐sized HZSM‐5 zeolites modified with trimethyl phosphate exhibited enhanced catalytic performance for OCC of full‐range FCC gasoline.

Fluid Catalytic Cracking Technology for Maximum Gasoline Production

Increasing gasoline production in FCC unit can improve the utilization efficiency of petroleum resources and gain economic benefit.This paper discusses the technical principles for increasing FCC gasoline yield from the aspects of feedstock properties,operating conditions,LCO(light cycle oil)recycling,catalyst selection and reactor type,and illustrates the industrial application examples for maximizing gasoline production.The technical measures,such as optimizing the feedstock,properly increasing the catalyst activity and reaction temperature,recycling LCO or hydrotreated LCO,applying high gasoline yield catalyst,and adopting the two-zone riser reactor,are proposed to enhance the gasoline yield.

Study of Carbon Nanotube Supported Co-Mo Selective Hydrodesulphurization Catalysts for Fluid Catalytic Cracking Gasoline

In this paper, carbon nanotube supported Co-Mo catalysts for selective hydrodesulphurization （HDS） of fluid catalytic cracking （FCC） gasoline were studied, using di-isobutylene, cyclohexene, 1-octene and thiophene as model compounds to simulate FCC gasoline. The results show that the Co-Mo/CNT has very high HDS activity and HDS/hydrogenation selectivity comparing with the Co-Mo/γ-Al2O3 and Co-Mo/AC catalyst systems. The saturation ratio of cyclohexene was lower than 50%, and the saturation ratio of 1,3-di-isobutylene lower than 60% for the Co-Mo/CNT catalysts. Co/Mo atomic ratio was found to be one of the most important key factors in influencing the hydrogenation selectivity and HDS activity, and the most suitable Co/Mo atomic ratio was 0.4. Co/CNT and Mo/CNT mono-metallic catalysts showed lower HDS activity and selectivity than the Co-Mo/CNT bi-metallic catalysts.

Study on Reaction Mechanism for Cracking FCC Gasoline on Acid Catalyst

This article is based on the experimental data on reaction of FCC naphtha in the presence of acid catalysts. The data published in the literature were reprocessed and compared with experimental data and the relationship of hydrogen and methane contained in the dry gas with the conversion rate was identified.The similarity between the route for cracking of olefin enriched FCC gasoline and the route for reaction of individual hydrocarbons was deduced, while the route for formation of ethylene in dry gas was also proposed to identify the relationship between the reaction path for formation of ethylene and the conversion rate.

Synthesis of La-Modified Ultra Stable Zeolite L and Its Application to Catalytic Cracking Catalyst

A new type of zeolite La-USL （ultra stable zeolite L （zeolite USL） modified by La）, which has superior activity, stability and selectivity in catalytic cracking of hydrocarbons and thus can be used as an active catalyst component, is reported in this paper. The zeolite L with relative crystallinity of above 90% was synthesized by the hydrothermal crystallization method under optimum conditions and characterized by means of XRD, NH3-TPD and isotherm adsorption techniques. The in-situ synthesized zeolite L with a SiO2/Al2O3 mole ratio of 5-6 was modified by cation ion exchange, hydrothermal dealumination and chemical modifications with La in order to prepare La-containing USL with a higher framework SiO2/Al2O3 mole ratio of 15-30. The modified zeolite La-USL was used as an active additive component of fluid catalytic cracking （FCC） catalyst and the resulting catalysts were evaluated by microactivity test （MAT） and fixed-fluidized bed （FFB） experiments using heavy oil as feedstock. The influence of La content in La- USL on cracking product distribution, gasoline group composition and research octane number （RON） was investigated. The results showed that when La content in La-USL was 0.8 wt%, the addition of the corresponding La-USL could result in a FCC catalyst that produced significant improvement in product distribution and gasoline quality.

Effect of Operating Parameters on Composition of Dry Gas Obtained During Gasoline Cracking Process

The influence of operating parameters on ethylene content in dry gas obtained during catalytic cracking of gasoline was investigated in a pilot fixed fluidized bed reactor in the presence of the MMC-2 catalyst. The results have shown that the majority of dry gas was formed during the catalytic cracking reaction of gasoline, with a small proportion of dry gas being formed through the thermal cracking reaction of gasoline. The ethylene content in dry gas formed during the catalytic cracking reaction was higher than that in dry gas formed during the thermal cracking reaction. The ethylene content in dry gas formed during catalytic cracking of gasoline with a higher olefin content was higher than that in dry gas formed during catalytic cracking of gasoline with a lower olefin content, which meant that the higher the amount of carbonium ions was produced during the reaction, the higher the ethylene content in the dry gas would be. An increasing reaction temperature could increase the percentage of dry gas formed during thermal cracking reaction in total dry gas products, leading to decreased ethylene content in the dry gas. An increasing catalyst/oil ratio could be conducive to the catalytic cracking reactions taking place inside the zeolite Y, leading to a decreased ethylene content in the dry gas. A decreasing space velocity could be conducive to the catalytic cracking reactions taking place inside the shape-selective zeolite, leading to increased ethylene content in the dry gas.

Highly Selective Conversion of Olefin Components in FCC Gasoline to Propylene in Monolithic Catalytic Reactors

The demand for propylene has been growing recently. The concentration of olefins in the gasoline is strictly limited by the related environmental regulations. The olefins contained in the gasoline used as the feed could be cracked into light olefins to slash the olefin concentration in the gasoline to yield more propylene at the same time. The monolithic catalyst washcoated on the modified ZSM-5 zeolite was used in the experiments. The effect of the temperature, the Si/Al ratio in ZSM-5 and the addition of the rare earth elements on the selectivities and the yields of the light olefins were studied. The high yields of propylene and butene could be obtained under the experimental conditions of a higher temperature and Si/Al ratio with the addition of rare earth elements.

Industrial Application and Fundamental Research Progress on Fluid Catalytic Cracking Technology of Downer Reactors

Fluid catalytic cracking(FCC)technologies of downer reactors,which have reached the demonstration or commercial scale,are systematically discussed,i.e.,millisecond catalytic cracking,fluidization lab of Tsinghua University,and high-severity FCC.Moreover,aiming to promote industrial application,the fundamental studies are comprehensively described,particularly focusing on high-density downer reactors,clusters,and up-scaling.Furthermore,from the perspective of industrial application,some research directions toward further developments are suggested.

Development and Commercial Application of RFCC Catalyst for Reducing Sulfur Content in Gasoline

The sulfur-reducing functional component the Lewis acid-base pair compound and associated active zeolite component were developed to prepare the RFCC catalyst DOS for reducing sulfur content in gasoline. The results of catalyst evaluation have revealed that the Lewis acid-base pair compound developed hereby could enhance the conversion of macromolecular sulfur compounds by the catalyst to promote the proceeding of desulfurization reactions, and the synergetic action of the selected zeolite and the Lewis acid-base pair compound could definitely reduce the olefins and sulfur contents in gasoline. The heavy oil conversion capability of the catalyst DOS thus developed was higher coupled with an enhanced resistance to heavy metals contamination to reduce the sulfur content in gasoline by over 20%. The commercial application of this catalyst at the SINOPEC Jiujiang Branch Company has revealed that compared to the GRV-C catalyst the oil slurry yield obtained by the catalyst DOS was reduced along with an improved coke selectivity, an increased total liquid yield, and a decreased olefin content in gasoline. The ratio of sulfur in gasoline/sulfur in feed oil could be reduced by 20.3 m%.

Analysis of Measures and Effect on Reducing Olefin Content in Gasoline

This article refers to major measures for reducing olefin content of automotive gasoline and the effect after adoption of these measures. The key for reducing olefin content in China's automotive gasoline pool is to reduce the olefin content of FCC naphtha. The domestic refiners apply the olefinreducing catalyst to decrease the olefin content of FCC gasoline as a convenient and cheap means to meet the national standard for automotive gasoline at the present phase. Furthermore, the novel domestic FCC reaction processes, such as the MIP, MGD, FDFCC and other processes can also apparently reduce olefin content in FCC gasoline. In order to further reduce the olefin content in gasoline to meet more stringent standard for automotive gasoline, Chinese refiners should optimize the processing scheme while aggressively disseminating hydrogenation process along with development of catalytic reforming,alkylation, etherification and other processes to completely change the simplistic composition of domestic gasoline pool.

Study on the Role of Thermal Cracking in FCC Cycle

A bench-scale fixed fluidized bed reactor was used to study the distribution and quality of productsderived from thermal cracking of VGO. Test results had shown that the space velocity has minor effect onthermal cracking reaction. The depth of thermal cracking reaction was mainly affected by the reaction temperature.At different reaction temperatures the form of free radicals thus initiated varied, resulting in different productdistribution. At low temperature C10= and C11= olefins dominated in thermally cracked gasoline products,whereas at higher temperature C6=C9= olefins dominated in thermally cracked gasoline products, amongwhich C6 and C7 olefins were mainly composed of 2M1C5= and 2E1C5=. Difference in olefin structure can leadto different reaction pathways of catalytic cycle.

A New FCC Process MIP for Production of Clean Gasoline Component

A concept of two different reaction zones was proposed based on the FCC reaction mechanism,and verified by the experimental results of a fixed fluidized bed reactor. The concept was used to design a novel reactor with corresponding operation measures. Further experiments were conducted on the newly designed pilot scale riser reactor. In comparison with the conventional FCC at relatively equivalent conversion,the pilot test results had shown that the olefin content in the cracked naphtha dropped by 12.4%, and both of iso-paraffin and aromatics increased by 6%, and its MON increased by 1.3 units while maintaining the RON of the naphtha unchanged, and its sulfur content was reduced by 15% with a significant extension of its induction period for Shengli VGO + VR.

Commercial Test of HGY-2000R FCC Catalyst for Maximizing Gasoline Yield

HGY-2000R catalyst developed by Research Institute of Petroleum Processing, SINOPEC wastested in the RFCC unit, Ulsan complex, SK Corporation, Korea from July to August 2002. The primaryresults of commercial test show that it has good performance of higher activity, good hydrothermal stability,higher residue cracking ability, good coke selectivity and good fluidization properties as well as maximizinggasoline yield with a lower olefin content.

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

The effects of reaction temperature,mass ratio of catalystto oil,space velocity,andmass ratio of water to oil on the product distribution,the yields of light olefins(light olefins including ethylene,propylene and butylene)and the composition of the fluid catalytic cracking(FCC)gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated.The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction con-ditions.The olefins(olefins with C atom number above 4)content of FCC gasoline was markedly reduced,and the aromaticscontent andoctanenumber were increased.The upgraded gasoline met the new standard of gasoline,and meanwhile,higher yields of light olefins were obtained.Furthermore,higher reaction temperature,higher mass ratio of catalyst to oil,higher mass ratio of water to oil,and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production.

Study on Commercial Application of FCC with Auxiliary Gasoline Reactor for Improving FCC Naphtha Quality

This article introduces the commercial application of FCC technology equipped with a gasoline auxiliary reactor in the RFCC unit at PetroChina Harbin Petrochemical Branch Company. Test results have shown the excellent outcome for commercial application of the gasoline upgrading in the auxiliary reactor to reduce the olefin content in FCC naphtha. Application of this technology can reduce the olefin content in FCC naphtha to less than 35 v%. Adjustment of the FCC operation towards more severe conditions can further reduce the olefin content in FCC naphtha to less than 20 v%, so that the FCC naphtha can meet the current standard or meet more stringent specification requirements in the future to achieve compelling economic and social benefits.

催化裂化催化剂LPC-65的工业应用

介绍LPC-65催化裂化催化剂在中国石油兰州石化公司1.20 Mt·a^(-1)重油催化裂化装置上的工业应用。结果表明,当LPC-65催化剂加入量达到系统藏量的50%时,与空白标定期相比,重油转化率和汽油收率分别增加1.24和0.62个百分点,柴油收率降低1.24个百分点,汽油烯烃下降4.09个百分点,异构烷烃和芳烃分别上升4.09个百分点和0.67个百分点。表明使用LPC-65催化剂后,重油转化能力增加,汽油降烯烃效果显著。

催化裂解装置灵活调节化工品与油品的总流程方案研究

面对国内炼油产能过剩的局面,炼油厂向化工转型势在必行。由于油品市场与化工品市场均具有强周期性,因此炼油厂在转型过程中需要提高清洁油品与化工原料的生产灵活性,以实现炼油厂营业收入最大化。以国内炼油厂典型总流程加工路线为基础,设计了虚拟炼油厂,针对该虚拟炼油厂,研究设计了以催化裂解为核心手段的总流程灵活转型规划方案:裂解汽油经加氢抽提装置生产化工品、裂解汽油经适当处理后通过S Zorb装置生产清洁油品。在原油加工总量不变的情况下,与基础方案相比:催化裂解生产化工品方案的汽油和柴油总产率下降了11.20百分点,烯烃、芳烃产率分别上升了5.15、6.39百分点;催化裂解生产清洁油品方案的汽油和柴油总产率下降了3.55百分点,烯烃、芳烃产率分别上升了4.69、2.15百分点。

降低催化裂化汽油苯含量的处理措施

文章介绍了降低催化裂化汽油苯含量的技术攻关思路、改造方案及具体处理措施。结果表明,采用分馏的方法分离并脱除催化裂化汽油中的富苯馏分,可以实现降低汽油苯含量的目标,苯的体积分数由1.30%降至0.75%以下,解决了企业生产的汽油产品苯含量质量指标超标的难题。