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Home , Alkylation, Ethylene

New Technologies and Alternative Feedstocks in Petrochemistry and Refining DGMK Conference October 9 – 11, 2013, Dresden,

Research and Development for Production Mingwei Xue, Hongmin Sun, Zhenhao Shen, Bin Zhang, Mingyao Huan, Weimin Yang SINOPEC Shanghai Research Institute of Technology, China

Abstract Ethylbenezene (EB) is important raw material for the production of . Now, EB is mainly produced by the of with catalyzed by in vapour phase or liquid phase. Shanghai Research Institute of Petrochemical Technology (SRIPT) began to research the catalysts for the production of ethylbenezene in 1993. With near 20 years work, three series of catalysts for the alkylation of benzene with pure ethylene, dilute ethylene and are in commerical in China. This paper mainly introduced the research and development of SRIPT for the EB production.

1. Introduction EB is important raw material for the production of styrene. With the increased consumption in China, the China capacity for EB increased rapidly in the recent years. EB is mainly produced by the alkylation of benzene with ethylene. Due to the corrosivity of AlCl3, and other problems associated with its safe handling and disposal, most manufacturers with the traditionally liquid-phase AlCl3 processes were move toward zeolite catalyzed processes. Zeolite catalyzed processes are licensed by Mobil–Badger, Lummus–UOP, CDTech.[1, 2] Since 1980’s, a great amount of work had been done to develop the technology for the production of ethylbenezene in China. Dalian Institute of Chemical Physics, Chinese Academy of Sciences, SINOPEC Corp. Research Institute of Process (PIPP) and SRIPT consequently developed the technology for the production of ethylbenezene. With near 20 years work, SRIPT had developed three series catalysts and technology for the production of ethylbenezene by alkylation of benzene with pure ethylene, dilute ethylene and biomass ethanol in vapor phase, respectively. And the three series technology are all in commercial. In this paper, the research process, catalytic ability and application of these catalysts and technology of SROPT are introduced.

2. Alkylation of benzene with pure ethylene method Since 1993, SRIPT began to research for the catalysts for the alkylation of benzene with pure ethylene in vapour phase. The catalytic abilities of ZSM-5, ZSM-11 and ZSM-23 for the alkylation of benzene with ethylene were studied. And the effect of the ration of SiO2/Al2O3 and crystalline size were also studied. It was found that the ZSM-5 with moderate SiO2/Al2O3 ratio and crystalline size showed the high catalytic activity and selectivity to EB. Then, the AB-96 was developed with modified ZSM-5. In 1999, AB-96 catalyst was used on the plant of Panjin Ethylene Industry Corporation for industrial experimental. The results showed that AB- 96 displayed better catalytic ability than the catalysts used before. AB-97 catalyst was developed by further optimizing the preparing method [3, 4]. Table 1 exhibited the performance of AB-97 and reference catalyst on the same plant. AB-97 catalyst showed the higher catalytic active stability and longer regeneration period. In 2003 and 2007, AB-97 catalyst was commercialied on the plants of SINOPEC Guangzhou branch and Changzhou DOHOW chemical, respectively. Now, the AB-97 catalyst is commercially used in all the plants for the alkylation of benzene with pure ethylene in vapour phase in China.

DGMK-Tagungsbericht 2013-2, ISBN 978-3-941721-32-6 231 New Technologies and Alternative Feedstocks in Petrochemistry and Refining

The major by-product of alkylation of benzene with ethylene is dithylbenezene. Generally, EB production can be improved by of benzene with diethylbenezene. In 2003, AB-97-T catalyst was developed by SRIPT and used on the plant of Daqing Petrochemical Company for industrial experimental. The results for the performance of AB-97-T and reference catalyst on the same plant were exhibited in Table 2. The AB-97-T displayed higher activity that can reach high conversion of diethylbenzene at relative low reaction temperature. And the catalyst can work at relative higher capacity [5].

Table 1 Performance of AB-97 and the Reference Catalyst in the Alkylation of Benzene with Ethylene First Cycle Item AB-97 Catalyst Reference Catalyst Reaction Temperature /℃ 389.00-389.00 389.00-400.00 Reaction Pressure /MPa 1.62-1.70 1.61-1.72 Benzene/Ethylene /(mol/ mol) 6.86-7.40 7.18-7.39 Ethylene /(WHSV /hr-1) 1.97-1.99 1.93-1.95 Conversion /% 99.94-99.51 99.92-99.06 Selectivity /% 99.66-99.27 99.43-99.12 Ethylbenzene Quality /% 99.65-99.75 99.55-99.70 Regeneration Cycle /months 21 12

Table 2 Performance of AB-97-T and Reference catalyst in transalkylation of benzene with diethylbenzene catalysts First Cycle Second Cycle AB-97-T Reference AB-97-T Reference Item Catalyst Catalyst Catalyst Catalyst Reaction Temperature /℃ 430.0~439.0 435.0~447.0 432.0 436.0 Reaction Pressure /MPa 0.62~0.67 0.63~.067 0.64 0.65 Benzene/DiEB /wt 2.91~3.10 2.98~3.12 3.20 3.15 Total WHSV /hr-1 33.5~35.5 31.7~33.8 34.9 32.6 Conversion /mol% 59.1~41.5 56.0~32.60 60.7 57.0 Selectivity /% 100.0 100.0 100.0 100.0.

Base on the catalysts, SRIPT developed the technology for the production of EB by alkylation of benzene with pure ethylene in vapour phase. In 2000, the plant of Danhua group was re-build with this technology to instead of the AlCl3 method. In 2004, the plant of Panjin Ethylene Industry Corporation was extended by this technology. In 2005, the plant of Changzhou DOHOW chemical, the plant with the biggest capacity (160 kt EB/y) of China, was build with this technology.

3. Alkylation of benzene with dilute ethylene method Off gas (ROG) stream of a refinery contain a great amount of ethylene, which can be used as raw material of EB. SRIPT began to research for the catalysts for the alkylation of benzene with dilute ethylene (ROG). The catalysts for the alkylation of benzene with dilute ethylene are similar as those for the alkylation of benzene with pure ethylene in vapor phase. However, ROG contains a great amount of N2, H2 and . Then, the reaction is performed at relative low ethylene partial pressure. On the other hand, ROG contains some impurities, such as H2S, C3H6 et al., which may affect the reactive ability of the catalysts. So the activity and the resistance to impurities of the catalysts for the alkylation of benzene with dilute ethylene should be improved. In 2004, SRIPT began to research for the catalysts for the alkylation of benzene with dilute ethylene (ROG). The ZSM-5 with smaller crystalline grain was prepared and the ZSM-5 was modified with new method. Then, The SEB-08 catalyst was developed, which showed high conversion of ethylene and high selectivity to EB.

232 DGMK-Tagungsbericht 2013-2 New Technologies and Alternative Feedstocks in Petrochemistry and Refining

In 2009, the SEB-08 was used on the plant of Hainan Shihua Jiasheng Chemical Co., Ltd. for industrial experimental. The results are shown in Table 3. Comparing to the catalyst used in the plant before, SEB-08 can work at relative high charge and lower benzene/ethylene ration. And the catalyst showed higher conversion of ethylene and longer and regenerate period[6].

Table3 Performance of SEB-08 and the reference catalyst in the alkylation of benzene with dilute Ethylene

Item SEB-08 catalyst Reference catalyst

Charge /% 70-106 52-88

Benzene/ethylene /(mol/mol) 5.5-6.0 6.0-7.0 Conversion of ethylene /% 97.28-99.62 75.12-99.61 Life /M 28 24 Regenerate period /M 12 8 Xylene/EB /ppm 500-900 800-1500

In 2009, SRIPT, Corp. Research Institute of Petroleum Processing and Luoyang Petrochemical Engineering Corporation of SINOPEC combined to develop the technology for the alkylation of benzene with dilute ethylene. In this method, the alkylation of benzene with ethylene is performed in vapor phase and the transalkylation of benzene with diEB is performed in liquid phase. In this process, the pretreatment of ROG is simple that only most H2S and propylene are removed from ROG. SEB-08 and AEB-1H catalysts were used as catalysts for alkylation and transalkylation reaction, respectively. With this technology, the EB purity of the product is over 99.8% and the xylene content of the product is lower than 800 ppm. Due to the low cost of raw material, the cost for the production of EB is greatly decreased. So the technology was spread rapidly in China. Now, the technology was already commercialied on two plants and will be commercialied on four plants in building. However, the main drawback of this process is that the capacity is relative low (usually about 100 kt EB/y) which controlled by the amount of ethylene of ROG.

4. Alkylation of benzene with ethanol method Ethylbenezene can also be produced by alkylation of benzene with biomass ethanol. With this method, the source of raw material is increased. A great amout of H2O is produced during the alkylation of benzene with ethanol. So high hydrothermal stability of the catalysts are needed. La2O3 and P were used to modify the catalyst to increase the hydrothermal stability of the catalyst[7]. Then, the DF-AS catalyst with high hydrothermal stability was developed by SRIPT in 2007, which displayed high catalytic ability for the alkylation of benzene with biomass ethanol. The catalyst was commercialied in the industrial plant with capacity of 200, 000 t/y. As was shown in table 4, the conversion of ethanol is about 99.99% and the ethyl selectivity is over 99.7%. The first cycle of the catalys is over 12 month. The purity of ethylbenzene in product is over 99.7% and the xylene is lower than 900 ppm. However, due to the increase of the price of ethanol during the last a few years, the economy of this process is decreased.

DGMK-Tagungsbericht 2013-2 233 New Technologies and Alternative Feedstocks in Petrochemistry and Refining

Table 4 Performance of DF-AS catalyst in the alkylation of benzene with ethanol Items DF-AS Temperature (°C) 360∼400 Pressure (MPa) 1.0∼1.8 Benzene/Ethanol (mol/mol) 6.0∼7.0 Ethanol WHSV (h-1) 0.5~0.8 Ethanol conversion (%) >99.0 Selectivity (%) >99.0 EB purity (wt%) >99.6 Catalyst lifetime (year) >2

5. Summary With near 20 years work, SRIPT had developed three series of catalysts for the alkylation of benzene with ethylene in vapor phase. These catalysts were in commerical in China and performed well on the plants. SRIPT also developed the corresping technology for the production of EB. Due to the low cost of raw material, the technology for the alkylation of benzene with dilute ethylene will be spread in the next 5 years. The method for the alkylation of benzene with ethanol can use ethanol as raw material, which can be produced by biomass and easy to be transported. These technologies had enriched the raw materials for the production of EB.

References [1] PEREGO C, INGALLINA P. Recent advances in the industrial alkylation of aromatics: new catalysts and new processes [J], Today, 2002, 73 (1-2) : 3-22. [2] DEGNAN J T F, SMITH C M, VENKAT C R. Alkylation of aromatics with ethylene and propylene: recent developments in commercial processes [J], Applied Catalysis A: General, 2001, 221 (1-2) : 283-294. [3] SUN H, YANG Wn, CHEN Q et al. Commercial Application of AB- 96 Catalyst [J]. Avances in Fine , 2003,4(3):28-30. [4] SUN H, YANG W, LIAO B, et al. Research and Comerical Application of AB-97 Catalysts for Preparing Ethylbenzene by Vapor Phase Alkylation [J]. Chemical Reaction Engineering and Technology, 2006,22(3):206-210. [5] SUN H, YANG W, GUAN Y et al. Commercial application of AB-97-T catalyst for synthesis of ethylbenzene by vapor phase transalkylation [J]. Industrial Catalysis, 2005,13(9):17-19. [6] ZHANG Y TIAN Q MA X, Commercial application of new alkylation catalyst for production of ethyl benzene from dilute ethylene [J]. Petrolum Refinery Engineer, 2012, 42 (10): 59-61. [7] YANG W, SUN H, LIU W, etal. Processes for synthesizing ethylbenzene from ethanol and benzene: US, 201113158709 [P].

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