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\"Lanzhou Jiaotong University\", 2012. Added to favorites. Research on the catalytic distillation process for etherifying FCC gasoline – Huang Jing. [Abstract]: FCC gasoline is one of the main sources of fuel for vehicles; in China, it accounts for 75% of the total gasoline produced. It is characterized by high levels of olefins and sulfur, as well as poor stability. The quality of this gasoline does not meet the requirements of new standards, which constitutes a major challenge in improving gasoline quality. Currently, the main methods employed by domestic refining companies to reduce the olefin and sulfur content in FCC gasoline are hydroprocessing, catalytic olefin reduction, and light gasoline etherification technologies. The hydrogenation method can effectively reduce the olefin and sulfur content in gasoline, but it has drawbacks, including high hydrogen consumption and significant loss of octane rating ； Using catalytic olefin reduction can effectively lower the olefin content in gasoline, but there is also the issue of low yield of gasoline products ； The use of light gasoline etherification technology has become one of the effective ways to improve the quality of catalytic gasoline. There has been extensive research on catalytic gasoline etherification technology both domestically and internationally. The characteristic of this technology is that the tertiary alkenes present in light gasoline can undergo an etherification reaction with CH3OH to produce corresponding ethers. This process reduces the olefin content in gasoline while increasing its octane rating; moreover, it converts about 4% of the methanol into components of gasoline. It is thus a process for increasing the volume of gasoline produced, as well as a method for converting low-value methanol into high-value gasoline components. As a new technology for catalytic gasoline modification, light gasoline etherification features mild reaction conditions, a relatively simple process, and significant etherification effects. It has attracted widespread attention from refineries around the world, which are competing to develop new technologies for light gasoline etherification using various processes. Well-known foreign companies such as CDTECH, UOP, Neste, ARCO, IFP, and BP have developed industrial technologies for the etherification of catalytic light gasoline, and have exported these technologies to the international market. This paper investigates the catalytic distillation process for the etherification of FCC light gasoline. It focuses on the separation of catalytically cracked gasoline into light gasoline components and heavy gasoline components; the tertiary alkenes present in the light gasoline can undergo etherification reactions with methanol to produce corresponding ethers, thereby reducing the alkene content in the light gasoline and increasing its octane rating. Heavy gasoline undergoes hydrodesulfurization to reduce the sulfur content in catalytic gasoline; the etherification technology for light gasoline is combined with the hydrodesulfurization technology for heavy gasoline to create a complete set of process technologies, thereby producing clean gasoline. The FCC light gasoline etherification process studied in this paper includes: first, the separation of FCC light gasoline, where a multi-functional distillation tower is used to separate the FCC gasoline into a light gasoline fraction with a boiling point of less than 70°C and a heavy gasoline fraction with a boiling point of more than 70°C ； The second method is selective hydrogenation: the light gasoline obtained after cutting enters a selective hydrogenation reactor to remove dienes ； Third is the fixed-bed pre-etherification reaction; light gasoline contains large amounts of C5 and C6 tertiary alkenes, which can undergo etherification reactions with methanol to produce methyl tert-pentyl ether (TAME) and methyl tert-hexyl ether (THXME) ； Fourthly, it facilitates deep etherification in the catalytic distillation tower; the material coming out of the fixed-bed reactor enters this tower for deep etherification, resulting in TAME-type gasoline blending components. This approach helps to reduce the olefin content in gasoline and increase its octane rating. The reaction kinetics of the etherification of isopentene, as the representative component, with methanol to produce methyl tert-butyl ether (TAME) in a micro fixed-bed etherification reactor were studied. The kinetic equation for the reaction of isoprene with methanol was investigated. After verifying this kinetic equation, the average relative error between the calculated values and experimental values of the isoprene conversion rate was less than 5%, indicating that this equation can effectively describe the etherification reaction of isoprene. The FCC light gasoline separation process was studied. Separation experiments were conducted in a laboratory-scale multi-functional distillation column with a feed rate of 2 L/h. Several factors affecting the efficiency of light gasoline separation were investigated, including the number of tray stages, feed position, operating pressure, reflux ratio, and top product yield. Based on these experiments, the optimal operating parameters for the multi-functional distillation column were determined as follows: the column had 16 tray stages, with the feed located at the 5th tray; the feed temperature was 70°C, the bottom temperature of the column was 195°C, the top temperature was 67°C, the top pressure was 0.118 MPa, and the reflux ratio was 1.0. Under these conditions, the yield of C5 tertiary alkenes was 100%, while the yield of C6 tertiary alkenes was 95.62%. As a result, the FCC gasoline was separated into light gasoline with a temperature of ≤70°C. The selective hydrogenation of dienes was carried out in a laboratory microreactor using the LNEH-1 catalyst. During the experiment, the ability of the LNEH-1 catalyst for removing dienes as well as its isomerization properties were evaluated. The results showed that the catalyst could remove more than 80% of the dienes, and it also exhibited good isomerization capabilities. The light gasoline obtained after hydrogenation was used as a raw material for etherification. The fixed-bed pre-etherification process for light gasoline was studied in a 2 L/h fixed-bed reactor. The conditions affecting the fixed-bed etherification reaction were investigated, including feed space velocity, reaction temperature, and oil-to-alkanol volume ratio. The optimal reaction conditions for fixed-bed etherification were determined to be: a feed space velocity of 2 h^-1, a reaction temperature of 65°C, and an oil-to-alkanol volume ratio of 10:1. Under these conditions, the conversion rate of C5 active olefins was 66.5%, while that of C6 active olefins was 48.8%. On a catalytic distillation column with a laboratory feed rate of 2 L/h, the process of deep etherification of light gasoline using catalytic distillation was studied. The effects of feed rate, reaction temperature, alcohol-to-olefin ratio, and reflux ratio on the catalytic distillation reaction were investigated. Through experiments, the optimal operating parameters for deep etherification in this catalytic distillation column were determined: feed temperature of 65°C, reflux ratio of 1.0, top temperature of 60°C, top pressure of 0.243 MPa, bottom temperature of 113°C, and bottom pressure of 0.286 MPa. Under these operating conditions, the overall conversion rate of C5 active olefins was 82.5%, while that of C6 active olefins was 71.0%. Through the analysis of etherified blended gasoline, the octane number of FCC gasoline subjected to etherification modification increased by 1–1.6 units, the olefin content decreased by 12.8%, and the saturated vapor pressure decreased by 18.8 kPa. Based on experimental research, this paper assumes the construction of an FCC light gasoline etherification industrial plant with a capacity of 100,000 t/year and conducts process flow simulation calculations. The calculations show that the theoretical number of theoretical plates in the catalytic distillation column is 30, the feed plate is located at position 27, the reaction section consists of 12 to 26 plates, and the feed temperature range is 65°C–73°C. For C, the reflux ratio ranges from 4 to 5.4, while the D/F ratio lies between 0.7 and 0.8. The catalyst loading height in the catalytic distillation column is 1.54 m, and the inner diameter of the column is 2.5 m. The calculation results can serve as a technical basis for the industrial design of the FCC light gasoline etherification catalytic distillation column. 【Keywords】: Catalytic cracking light gasoline; Catalytic distillation; Kinetics; Esterification; Aspen Plus simulation; 【Degree-awarding institution】: Lanzhou Jiaotong University; 【Degree level】: Master; 【Year of degree award】: 2012; 【Classification number】: TE624.48; 【Table of contents】: Abstract 4-6; Abstract 6-12; Introduction 12-25; 1.1 Introduction 12-13; 1.2 Foreign FCC light gasoline esterification technologies 13-19; 1.2.1 Characteristics of catalyst-treated light gasoline esterification products 14-15; 1.2.2 Neste’s light gasoline esterification technology 15; 1.2.3 UOP’s light gasoline esterification technology 15-16; 1.2.4 IFP’s light gasoline esterification technology 16-17; 1.2.5 CDTECH’s light gasoline esterification technology 17-18; 1.2.6 SPA’s light gasoline esterification technology 18; 1.2.7 ARCO’s light gasoline esterification technology 18-19; 1.3 Domestic FCC light gasoline esterification technologies 19-23; 1.3.1 Qilu Petrochemical Research Institute’s light gasoline esterification technology 19-20; 1.3.2 Fushun Petrochemical Company’s light gasoline esterification technology 20-21; 1.3.3 Sinopec Research Institute of Petroleum Chemistry’s light gasoline esterification technology 21-22; 1.3.4 Domestic simple light gasoline esterification technologies 22-23; 1.4 Rationale for the research topic and main contents 23-25; 2. Kinetics of the esterification reaction between isopentene and methanol to form TAME 25-32; 2.1 Experimental principle for synthesizing TAME 25-28; 2.1.1 Reaction principle 25; 2.1.2 Raw materials and catalysts 25-26; 2.1.3 Kinetic experiments and analysis methods 26; 2.1.4 Changes in the content of various components over time 26-27; 2.1.5 Influence of temperature on TAME content 27-28; 2.2 Establishment of kinetic equations 28-31; 2.2.1 Verification of kinetic equations 31; 2.3 Summary 31-32; 3. Research on catalytic distillation technology for FCC light gasoline esterification 32-57; 3.1 Principle and process of catalytic distillation for light gasoline esterification 32-35; 3.1.1 Principle of the esterification reaction between light gasoline and methanol 32-33; 3.1.2 Process flow of catalytic distillation for light gasoline esterification 33-34; 3.1.3 Experimental equipment 34; 3.1.4 Analysis methods 34-35; 3.1.5 Calculation of tert-pentene conversion rate 35; 3.1.6 Quantitative analysis method for esters 35; 3.2 Raw materials and catalysts for catalytic distillation of light gasoline esterification 35-38; 3.2.1 FCC gasoline 35-37; 3.2.2 Methanol 37; 3.2.3 Strongly acidic resin esterification catalysts 37-38; 3.2.4 Catalyst loading in the catalytic distillation column 38; 3.3 Study on the separation process of light gasoline from FCC gasoline 38-45; 3.3.1 Influence of the number of trays on separation efficiency 39-40; 3.3.2 Influence of the feed tray position on separation efficiency 40-41; 3.3.3 Influence of operating pressure on separation efficiency 41; 3.3.4 Influence of reflux ratio on separation efficiency 41-42; 3.3.5 Influence of top product recovery rate on separation efficiency 42; 3.3.6 Separation results 42-45; 3.3.7 Summary 45; 3.4 Selective hydrogenation performance of LNEH-1 catalyst 45-48; 3.4.1 Influence of reaction time on the selective hydrogenation performance of the catalyst 45-46; 3.4.2 Influence of reaction temperature on the selective hydrogenation and isomerization performance of the catalyst 46-47; 3.4.3 Influence of liquid space velocity on the selective hydrogenation and isomerization performance of the catalyst 47-48; 3.4.4 Summary 48; 3.5 Fixed-bed pre-esterification reaction of FCC light gasoline 48-52; 3.5.1 Influence of liquid space velocity on light gasoline esterification 48-49; 3.5.2 Influence of reaction temperature on light gasoline esterification 49-50; 3.5.3 Influence of oil-to-alcohol ratio on light gasoline esterification 50-51; 3.5.4 Results of light gasoline pre-esterification experiments 51-52; 3.5.5 Summary 52; 3.6 Experiments on deep esterification using catalytic distillation of light gasoline 52-57; 3.6.1 Raw materials and operating parameters for deep esterification in the catalytic distillation column 52-53; 3.6.2 Influence of alcohol-to-olefin ratio on the conversion rate of C5 active olefins 53-54; 3.6.3 Influence of reflux ratio on the conversion rate of C5 active olefins 54-55; 3.6.4 Results of deep esterification experiments using catalytic distillation 55-56; 3.6.5 Summary 56-57; 4. Analysis and measurement results of the properties of catalytically blended gasoline 57-60; 4.1 Comparison of octane numbers between blended gasoline and FCC gasoline 57; 4.2 Comparison of physical properties between blended gasoline products and raw materials 57-58; 4.3 Summary 58-60; 5. Simulation calculation of the process flow for a 100,000 t/a FCC light gasoline esterification catalytic distillation plant 60-64; 5.1 Simulation calculation using Aspen Plus software 60-63; 5.1.1 Distribution of temperature with the number of trays 60-61; 5.1.2 Distribution of mass flow rates of gas and liquid phases with the number of trays 61; 5.1.3 Distribution of mass contents of C5 tertiary alkenes and TAME with the number of trays 61-62; 5.1.4 Distribution of mass contents of C6 tertiary alkenes and THXME with the number of trays 62-63; 5.2 Summary 63-64; Conclusions 64-66; Acknowledgments 66-67; References 67-71; Research achievements during the degree program 71