Commercial Application of Novel Heavy Oil Catalytic Cracking Catalyst HSC

Transcription

1 Catalyst Research China Petroleum Processing and Petrochemical Technology 2017, Vol. 19, No. 1, pp March 31, 2017 Commercial Application of Novel Heavy Oil Catalytic Cracking Catalyst HSC Zhang Zhimin (Qilu Branch of SINOPEC Catalyst Co., LTD, Zibo ) Abstract: The commercial application of a novel RFCC catalyst HSC used in an 1.4 Mt/a RFCC unit at a refinery A was introduced. The application results show that in comparison with the base catalyst, the yield of dry gas and slurry was reduced, while the total liquid yield, gasoline yield and LPG yield increased by 1.34, 5.05 and 1.43 percentage points, respectively. The properties of the products showed no significant change while the anti-abrasion strength of the catalyst was relatively high. Based on the mid-term, the summary and the daily statistics of long term industrial application practice, the HSC catalyst features a strong conversion ability of heavy oil, a high gasoline yield, a satisfactory product distribution and a good selectivity. Key words: heavy oil, FCC catalyst, industrial application, structural stability 1 Introduction FCC (fluid catalytic cracking) process, a major conversion process in petroleum refining, plays a key role at oil refineries and petrochemical plants. To many refineries, FCC unit is a crucial factor of gaining economic benefits and maintaining competitiveness in oil products market [1-2]. Processing of the FCC feedstock, which is getting increasingly heavy and inferior in recent years, needs a FCC catalyst that would have greater activity and hydrothermal stability to improve the ability of heavy oil conversion and resistance to heavy metal contamination. Therefore, the Y zeolite, which is a major active component in the FCC catalyst, is required to have high activity and structural stability. The catalyst needs to be ultra-stable and be rare-earth modified to accomplish this goal [3-9]. The SINOPEC Research Institute of Petroleum Processing (RIPP) has developed a new production process for manufacture of high stability zeolite and prepared HSY zeolite with a relatively high activity and stability. On this basis, a novel RFCC catalyst HSC has been developed to contain the high stability zeolite HSY as its active component [10]. The feedstock of the 1.4 Mt/a RFCC unit at the refinery A is a mixture of Linshang crude and Shengli crude. To improve the heavy oil conversion ability of the unit, the product distribution, and the liquid yield of light hydrocarbons, the HSC catalyst produced by the Qilu Branch of SINOPEC Catalyst Company has been ed in the FCC unit of the refinery A since July 4, Furthermore, the industrial s and long-term industrial application of the HSC catalyst also have been conducted. This article will present the industrial results of RFCC catalyst HSC in the 1.4 Mt/a RFCC unit of the refinery A and the continuous industrial application of the catalyst launched by the end of Design of HSC Catalyst and Its Main Performance RIPP and the Qilu Branch of SINOPEC Catalyst Company have jointly developed the unit for production of highly stabilized zeolite HSY in commercial scale. By optimizing the parameters of the highly stabilized zeolite process technology and constantly improving the unit, the continuous production of highly stabilized zeolite HSY has been successfully implemented. The highly stabilized zeolite HSY can satisfy the strict requirements for the FCC catalyst raised by the increasingly heavy FCC feedstock, because the zeolite HSY possesses a Received date: ; Accepted date: Corresponding author: Zhang Zhimin, zhangzm.chji@ sinopec.com. 11

2 satisfactory performance in terms of high stability, high silica-alumina ratio, good thermal and hydrothermal stability and high ability of heavy oil conversion. With the newly developed highly stabilized zeolite HSY serving as its major active component, the RFCC gasolineenhancing catalyst HSC has advantages of high stability, thermal stability, gasoline selectivity and heavy oil cracking ability. To enhance the ability of large molecule cracking and metal resistance, a macroporous material is selected as the matrix coupled with adding metal-resistant components during its preparation. The HSC catalyst has been successfully produced by the Qilu Branch of SINOPEC Catalyst Company in commercial scale. The main properties of the fresh catalyst produced at the Qilu Branch of SINOPEC Catalyst Company are listed in Table 1. Table 1 The primary properties of HSC catalyst HSC catalyst Chemical compositions,% Al 2 O Na 2 O 0.16 Fe 2 O SO 4 2- Physical properties Loss on ignition,% 11.8 Pore volume, ml/g 0.40 Specific surface area, m 2 /g 273 Apparent bulk density, g/ml 0.72 Attrition index,% h Paticle size distribution,% 0 20 μm μm μm 92.3 Average particle size, μm 71.9 Micro activity (800 o C, 4 h),% 80 As shown in Table 1, the HSC catalyst shows specific features of low sodium oxide content, high pore volume and specific surface area. Meanwhile, the micro-activity of the HSC catalyst is relatively high. 3 Industrial Tests and Application Process 3.1 Industrial unit overview The FCC unit which has been employed to conduct 1.5 industrial has a design capacity of 1.4 Mt/a, with the cracking reaction taking place in a riser reactor and a stacked two-stage regeneration process being employed to regenerate the catalyst. 3.2 Industrial and application programme To minimize the impact on production, the HSC catalyst was added into the unit through usual equilibrium addition method in small scale every day. To shorten the period of replacement, the frequent unloading method was adopted at the early stage, and the equilibrium catalyst was unloaded in small amount intermittently according to the inventory of reaction-regeneration system to maintain a proper micro-activity of the equilibrium catalyst. Industrial was conducted when the catalyst accounted for 70% of the system s inventory. During loading of the catalyst, the fresh catalyst should be added smoothly, and the catalyst consumption should be close to that of the reference catalyst. Meanwhile, the change of material balance should be paid attention to. The catalyst loading rate should be adjusted on the basis of product distribution and micro-activity, in order to maintain the micro-activity of the catalyst stabilized in the system and keep the unit functioning. The HSC catalyst was added into the system according to the scenario since July 4, The previous catalyst was renewed at a normal rate of catalyst consumption and loss in the unit. The HSC catalyst had been ed three times in commercial scale on the FCC unit at the refinery A. A group of selected previous catalyst was investigated starting from 7:00 on July 1 to 7:00 on July 3, 2009 during the blank s. On February 1, 2010, the HSC catalyst was intermediately ed, when the HSC catalyst accounted for 65% of the system inventory and the unit throughput was similar to that of the blank. The HSC catalyst was finally ed at 7:00 on October 25, 2010, when it accounted for 97% of the system inventory. The HSC catalyst has been applied commercially on the same unit in long term, after the successful completion of industrial on the FCC unit in October, So far the HSC catalyst has always been applied successfully in the FCC unit at the refinery A. 12

3 4 Results and Discussion 4.1 Unit throughput and analysis of properties of feedstock The unit throughput of the blank, the midterm and the summary reached t/d, t/d and t/d, respectively. The unit throughput of summary was by 144 t/d lower than that of the blank, while the unit throughput of intermediate and blank s was close between each other. The properties of feedstock used in three s are listed in Table 2. Table 2 Properties of the feedstock Density (20 o C), kg/m Carbon residue,% Distillation Range, o C 10%/30%/50% 349/413/ /418/ /409/457 <500 o C fraction distilled off,% Sulphur content, µg/g Nitrogen content, µg/g Metal content, µg/g Fe/ Ni/ V 7.3/12.5/ /12.3/ /12.5/3.2 SARA content,% Saturates Aromatics Resins Asphaltenes It can be seen from the properties of FCC feedstock listed in Table 1 that the heavy metal content, the SARA content and the density of the feedstock used in three s were close, except for the carbon residue of the feedstock used in the intermediate and summary s which was slightly lower than that of the feed oil used in the blank. 4.2 Primary properties of equilibrium catalyst The analysis results of the equilibrium catalyst of three s are presented in Table 3. It can be seen from the data listed in Table 3 that the micro-activity of equilibrium catalyst collected from three s was around 65. During the blank, the fresh catalyst consumption was kg/t. In comparison with the blank, the fresh catalyst consumption of intermediate and summary s was by kg/t and kg/t lower, respectively. In this way, with the catalyst consumption being reduced during the intermediate and summary s, the heavy metal content of the equilibrium catalyst remained close for the three cases, while the micro-activity of equilibrium catalyst of three s maintained at a steady level, evidencing that the catalyst had good stability when it was examined in the course of the intermediate and summary s. The specific surface area of the equilibrium catalysts collected during the intermediate and summary s was higher than that measured during the blank Table 3 Primary properties of equilibrium catalyst Physical properties Pore volume, ml/g Specific surface area, m 2 /g Apparent bulk density, g/ml Sieve composition,% 0 20 μm μm μm μm Average particle size, μm Metal content, μg/g Fe Na Ni V Sb Ca Micro activity Fresh catalyst consumption, kg/t

4 Table 4 The operating conditions of three s Fresh feed rate, t/h Regeneration air consumption in standard state, m 3 /min Disengager top pressure, kpa Riser reactor outlet temperature, o C Feed preheat temperature, o C Termination agent input, t/h st regenerator pressure, kpa st regenerator dense phase temperature, o C nd regenerator dense phase temperature, o C Recycle oil rate, t/h Fractionator top temperature, o C Fractionator feed temperature, o C Fractionator bottom temperature, o C Fractionator top pressure, kpa Fractionator top reflux, t/h , indicating that the HSY zeolite contained in the HSC catalyst possessed good structural stability and high crystallinity retention, so that the activity and stability of the HSC catalyst had be improved. Judging from the analysis result of particle size distribution, the fine powder content (with a particle size of 0 40 μm) demonstrated a declining tendency and the average particle size was smaller after HSC catalyst was applied, suggesting that the crushing strength of HSC catalyst was relatively high. It is generally acknowledged that the fluidization performance reaches the best when the fine powder content ranges from 15% 20%, which can enhance the transportation capacity without too much gas entrainment loss. When the amount of catalyst particles with a grain size of less than 20 μm increases significantly, the gas entrainment loss would be obvious. Starting from January 2010, fluctuation occurred to the fluidization process in the reaction-regeneration system, with the frequency of unloading catalyst increased and the catalyst loss decreased, indicating that the reduction of fine powder had a negative effect on fluidization. The catalyst particles, the size of which is smaller than 40 μm, are called the fine powder, while those catalyst particles with their size being larger than 80 μm are called the coarse grain. The ratio between the coarse grain content and the fine powder content is defined as the roughness coefficient. A higher roughness coefficient would lead to a worse fluidization status. Normally, the roughness coefficient should not be higher than 3. The blank had a roughness coefficient of 0.74, while the roughness coefficient of mid-term and summary reached 2.89 and 2.58, respectively. 4.3 Operating conditions The operating conditions of the reaction-regeneration system during three s are listed in Table Material balance The material balance data of three s are listed in Table 5. The properties of dry gas and LPG from three s are listed in Table 6. Judging from the statistics of material balance shown in Table 5, the gasoline yield of the summary was obviously higher than that of the blank Table 5 Material balance Fresh feed rate, t/h Recycle oil rate, t/h Material balance,% Dry Gas LPG Gasoline LCO Slurry Coke Loss Conversion,% Total liquid yield,%

5 Table 6 Properties of dry gas and LPG Dry gas composition, v% Carbon dioxide Hydrogen Air Methane Ethane Ethylene C H 2 /CH LPG composition, v% Propane Propylene n-butane + iso-butane n-butene + iso-butene trans-butene cis-butene C , while the LCO yield of the summary was lower than that of the blank. The liquid yield increased after the HSC catalyst was applied. Compared with the blank, the total liquid yield of the mid-term and the summary increased by 0.52 and 1.34 percentage points, respectively. Upon comparing the data on yields of other products, it is known that the yields of dry gas and slurry from the summary were lower than those from the blank, while the coke yield was higher, and the LPG and gasoline yields were obviously higher than those from the blank. The gasoline yield increased by 5.05 percentage points and the LPG yield increased by 1.43 percentage points. In general, thanks to the reasonable design of catalyst, after the adoption of the HSC catalyst the cracking depth increased, and the catalyst had better capability of heavy oil conversion, while the distribution of products was also improved. On account of the increased proportion of pipeline transported oil and the change in crude oil diet during the period of three s, the result of the s was affected to some degree. In comparison to the blank, the feedstock became lighter during the summary, while the coke formation and the medium pressure steam output increased. The decrease of gasoline yield and increase of LCO were caused by the quality control needs. In the mid-term, the dry point of gasoline was lower than that in the blank by 8 o C. According to the past experiences, the gasoline yield would increase by 2 percentage points if the dry point could be increased by 8 o C. Judging from the statistics spanning from February 10 th to 20 th, 2010, the dry point of gasoline remained nearly the same as that of gasoline obtained during the blank, and the yield of gasoline increased by nearly 2 percentage points while the total liquid yield increased by 0.8 percentage points. By taking into account the yield of LPG and gasoline, the conversion of catalytic reaction was improved. It can be seen from Table 6 that the content of C 3 + components in dry gas from the intermediate and the summary s was close or less, as compared with that of the blank, indicating to the good quality of dry gas. Upon suggesting that the content of Ni and Sb was close, the H 2 /CH 4 volume ratio measured during the intermediate and the summary s was less than that of the blank, which could reflect the strong metal tolerance ability of the HSC catalyst, resulting in an increased content of propylene in LPG. Since the catalytic cracking reaction system is a complex reaction network of parallel sequence, the product distribution varies with different reaction depth. Therefore, besides comparing the product distribution directly, the selectivity of product should also be considered. According to the statistical data on product selectivity, during the blank the selectivity of dry gas, LPG, gasoline and coke was 4.87%, 19.37%, 63.19% and 12.56%, respectively. Compared with the results of the blank, during the mid-term, the selectivity of dry gas was by 0.26 units higher, and the selectivity of LPG was by 1.25 units lower, while the selectivity of gasoline was by 0.31 units higher, and the selectivity of coke was by 0.68 units 15

6 higher. Compared to the results of the blank, during the summary, the selectivity of dry gas was by 0.83 units lower, and the selectivity of LPG was by 0.27 units higher, while the selectivity of gasoline was by 1.4 units higher, and the selectivity of coke was by 0.83 units lower. A conclusion could be drawn up from the above data that in comparison with the reference catalyst, the product selectivity, in particular the selectivity of dry gas, gasoline, and coke had been improved since the HSC catalyst was applied. 4.5 Properties of oil products The primary properties of stabilized gasoline, LCO and slurry are listed in Tables 7 9. Judging from the stabilized gasoline properties listed in Table 7, the research octane number (RON) of gasoline from the summary was 91.6, which was by 0.5 units higher than that from the blank. The motor octane number (MON) of gasoline from the summary was 81.0, which was the same as that from the blank. The induction period of stabilized gasoline was increased after the HSC catalyst was applied. Judging from the statistics on light diesel properties listed in Table 8, the light diesel fuel obtained from three s had low cetane number and poor quality. The catalytic diesel fuel still needs to be processed by hydrotreating or blended with straight-run diesel fuel to Table 7 Properties of stabilized gasoline Density (20 o C), kg/m Acidity, mgkoh/100ml Bromine value, gbr/100ml Reid vapor pressure, kpa Induction period, min Total nitrogen content, µg/g Sulfur content, µg/g Olefin mass fraction,% Distillation range, o C IP/50%/ EP 36/93/188 27/87/183 36/98/199 RON/ MON 91.1/ / /81.0 Table 8 Properties of LCO Density (20 o C), kg/m Acidity, mgkoh/100 ml Bromine value, gbr/100 ml Freezing point, o C Flash point, o C Cetane index Total nitrogen content, µg/g Sulfur content, µg/g Distillation range, o C IP/50%/90% 172/282/ /274/ /285/357 Table 9 Properties of slurry Density (20 o C), kg/m Viscosity (80 o C), mm 2 /s Viscosity (100 o C), mm 2 /s Carbon residue,% Solidification point, o C Total nitrogen content, µg/g Sulfur content, µg/g Distillation range, o C 2%/30%/50% 325/451/ /457/ /455/482 SARA content,% Saturates Aromatics Resins Asphaltenes Slurry solid content, g/l satisfy the specification requirements. It can be seen from Table 9 that the solid content of slurry from the intermediate and summary s decreased as compared to that from the blank, suggesting that the catalyst had a better performance than the contrast catalyst. The result of these s indicates that the density of slurry and carbon residue 16

7 increased, while the quality of slurry worsened and turned heavier. Compared with the contrast catalyst, the HSC catalyst possessed stronger bottoms conversion ability. 4.6 Daily statistical analysis report The statistics of industrial and daily production starting from January 2009 to the end of 2015 had been collected and made into charts. Figures 1 4 reveal the trends of change in feedstock properties and product yield before and after the HSC catalyst was applied, serving as the basis of daily statistical analysis. Among them, the HSC catalyst began to join the system 180 days after the start of statistics recording. The HSC catalyst had been used in the FCC unit of the refinery A for about 2,500 days by the end of Figure 1 shows the tendency of metal content in feedstock with time on stream. The statistical results of Figure 1 show that the vanadium content in feedstock was almost unchanged, and the nickel content increased slightly, while the iron content increased significantly with time on stream. The results revealed that the properties of Figure 1 Tendency of metal content in feedstock Fe content; Ni content; V content Figure 3 Tendency of total liquid yield Figure 4 Tendency of oil slurry yield feedstock were slightly heavier during the long term industrial application of the HSC catalyst as compared with that of the contrast catalyst. Figure 2 and Figure 3 show the tendency of gasoline yield and total liquid yield with time on stream, respectively. Figure 4 shows the tendency of slurry yield with time on stream. It can be seen from Figures 2 4 that the tendency of the total liquid yield and gasoline yield increased obviously while the tendency of oil slurry yield declined significantly after application of the HSC catalyst, which was consistent with the result of s. The statistical result has confirmed that industrial application result of the HSC catalyst in long term is consistent with that of the industrial s. It also indicates that the HSC catalyst demonstrates a strong ability to convert heavy oil and can achieve high gasoline yield and total liquid yield as compared with the contrast catalyst. 3 Conclusions Figure 2 Tendency of gasoline yield Compared with the contrast catalyst, the following conclusions can be drawn from the results of industrial s and application of the HSC catalyst on RFCC unit at 17

8 the refinery A. The total liquid yield obtained from the intermediate and summary s of the HSC catalyst increased by 0.52 and 1.34 percentage points along with the reduction of dry gas and slurry yield. During the summary, the gasoline yield and LPG increased by 5.05 and 1.43 percentage points, respectively. The product selectivity especially that related with the dry gas, gasoline and coke had been improved. The content of propylene in LPG increased without significant change in the properties of oil products. During the industrial application, the catalyst consumption and solid content of slurry showed a declining tendency, while the total liquid yield and gasoline yield showed an increasing trend and the slurry yield displayed a decreasing tendency. The HSC catalyst possessed high stability, a relatively strong metal tolerance, and high catalyst crushing strength. Also, the HSC catalyst showed strong capability of heavy oil conversion, satisfactory product distribution and selectivity, while the yield of high value products was obviously higher than that of the contrast catalyst. The industrial application has brought about great economic benefits. Reference [1] Sadeghbeigi R. Fluid Catalytic Cracking Handbook[M]. 2nd Edition. Houston: Gulf Professional Publishing, 2000: 1-39 [2] Chen Junwu. Catalytic Cracking Process and Engineering [M]. Beijing: SINOPEC Press, 2005: (in Chinese) [3] Grobet P J, Jacobs P A, Beyer H K. Study of the silicon tetrachloride dealumination of NaY by a combination of NMR and IR methods[j]. Zeolites, 1986, 6(1): [4] Wang Yingjun, Sun Yujia, Suo Yanhua, et al. Research progress in dealumination of USY zeolites[j]. Industrial Catalysis, 2015, 23(11): (in Chinese) [5] Skeels G W, Breck D W. Zeolite Chemistry. V. Substitution of Silicon for Aluminum in Zeolite via Reaction with Aqueous Fluorosilicate[C]//Proc. 6 th International Zeolite Conf. (Butterworths): 1984, [6] Martens J A, Grobet P J, Jacobs P A. The chemistry of the dealumination of faujasite zeolites with silicon tetrachloride[j]. Studies in Surface Science and Catalysis, 1991, 63: [7] Shu Yuying, Travert A, Schiller R, et al. Effect of ionic radius of rare earth on USY zeolite in fluid catalytic cracking: Fundamentals and commercial application[j]. Topics in Catalysis, 2015, 58(4/6): [8] Li Xuejin, Qiao Ke, He Lifeng, et al. Combined modification of ultra-stable Y zeolites via citric acid and phosphoric acid [J]. Applied Petrochemical Research, 2014, 4(4): [9] Han Guo, Sun Xiaoyan, Fan Hongfei, et al. Effects of different modification methods on structure and acidity of Y zeolite[j]. Petrochemical Technology & Application, 2015, 33(3): (in Chinese) [10] Zhang Zhimin, Zhou Lingping, Yang Lin, et al. Research and development of novel heavy oil catalytic cracking catalyst HSC-1[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2012, 28(1): 1-6 (in Chinese) Successful Application of Novel α-methylstyrene Hydrogenation Catalyst at Yanshan Petrochemical Company The SHP-A1 type catalyst for hydrogenation of α-methylstyrene (AMS) developed by the SINOPEC Shanghai Petrochemical Research Institute (SPRI) has been successfully applied in the No. 1 phenol unit at the Third Chemical Plant of Yanshan Petrochemical Company at the first attempt of commissioning. The said catalyst is the first AMS hydrogenation catalyst developed independently by the domestic institution and successfully applied in the industry, symbolizing the preliminary success of SPRI in terms of disseminating its hydrogenation technology into the phenol-acetone process. The No. 1 phenol unit at the Third Chemical Plant has a design capacity of 160 kt/a, which used to adopt overseas catalyst before commissioning of the AMS hydrogenation unit. On July 25, 2016 the SHP-A1 type hydrogenation catalyst was successfully applied in the phenol unit at the first attempt of operation. At present this hydrogenation unit operates smoothly, and the temperature distribution in the reactor bed is rational to deliver qualified product with the expected targets fulfilled. 18