Information on methanol synthesis of olefins
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Is there any information on the synthesis of olefins from methanol? I need it urgently; thank you all for your help
MTP (Methanol-to-Propylene) is a process that converts coal or natural gas into propylene via methanol. MTO (Methanol-to-Olefins), on the other hand, is a broader concept; its products are usually mixtures of low-carbon olefins such as ethylene and propylene. Given the not-so-optimistic situation of global oil supply and the advent of an era of high oil prices, MTP and MTO have become the most promising processes to replace naphtha-based routes for producing olefins. Some renowned international oil and chemical companies, such as BASF, Mobil, Lurgi, UOP, and Exxon, have conducted years of research on this topic. Domestic research institutions as well (such as the Southwest Research Institute of Chemical Engineering, Dalian Institute of Chemical Physics, Shanghai Research Institute of Petrochemical Technology, etc.) carried out pilot-scale studies in the 1990s. The reaction pathways of MTP and MTO are generally considered to consist of three steps: (1) Methanol first loses a molecule of water to form dimethyl ether, and methanol and dimethyl ether quickly reach an equilibrium mixture. Methanol/dimethyl ether molecules react with the acidic sites on the molecular sieve to form methoxy groups. (2) One of the C-H protons in the methoxy group gets protonated to form C-H+, which then forms a hydrogen bond with the -OH- group in the methanol molecule; this leads to the formation of an oxonium ion, and subsequently a C=C bond is created. (3) The C=C bond continues to undergo chain growth to form (CH2)n. When a molecular sieve is used as a catalyst in the reaction process, the product distribution is relatively simple, with C2–C4 compounds (especially ethylene and propylene) being the main products, and almost no products with carbon numbers higher than C5 are formed. The key technology in MTP and MTO processes is the catalyst. Due to the large amount of water present during the reaction process, and the need to regenerate and carbonize the catalyst at high temperatures frequently during operation, the thermal stability and hydrothermal stability of the catalyst are decisive factors affecting its chemical lifetime.
Thank you. Is there any more detailed information?
More detailed information is needed!
Methanol To Olefin (MTO) is the core technology of the coal-to-olefins process, which is a process for converting methanol into ethylene and propylene. The Methanol-to-Olefins (hereafter referred to as MTO) process has opened up a new route for producing basic organic chemical raw materials from coal or natural gas. It is the most promising alternative to the traditional method of producing olefins from naphtha, and it also represents an effective way to facilitate the expansion of coal-based chemical industries into the petrochemical sector. 1. Introduction to the MTO process: The concept of MTO was first proposed by the American company Mobil in the 1980s. Starting in 1992, UOP and Hydro began to work together on research related to MTO technology. Together, these two companies developed a new type of SAPO-34 silicoaluminophosphate molecular sieve catalyst. By controlling the location and strength of the acidic sites in this catalyst, it was possible to endow it with selectivity, thereby reducing the polymerization of low-carbon olefins and significantly increasing the selectivity for converting methanol into ethylene and propylene. The successful development of the SAPO-34 catalyst represents a significant advancement in the research on MTO processes; this catalyst has since been evolved into the more advanced MTO-100 catalyst. The Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has been conducting research on the MTO process since the 1980s. In 1993, a pilot study on a fixed-bed MTO process using ZSM-5 as a catalyst and a methanol processing capacity of 1 t/d was completed, and in the 1990s, the SDTO process for producing olefins from syngas via dimethyl ether synthesis was proposed. The SDTO process differs little from the MTO process; it also employs a fluidized-bed reaction-regeneration configuration, and its catalyst can be used in the MTO process as well. In this process, syngas is first converted into dimethyl ether in a fixed-bed reactor under the action of a metal-zirconia bifunctional catalyst in one step; thereafter, dimethyl ether is transformed into low-carbon olefins primarily composed of ethylene using a small-pore silica-alumina-phosphorus molecular sieve catalyst DO123 in a fluidized-bed reactor. 2. MTO process flow: The MTO process mainly comprises the following units: methanol feed gasification, reactor and regenerator, product condensation and dehydration, compression, oxidation recovery, impurity removal, distillation, and purification. The front part of the process is similar to the reaction and regeneration unit in catalytic cracking units in the refining industry, while the rear part is similar to the naphtha cracking gas separation unit in the petrochemical industry. 3. Main chemical reactions: On highly selective catalysts, MTO undergoes 2 reactions: 2CH3OH→C2H4+2H2O △H=-11.72kJ/mol; 3CH3OH→C3H6+3H2O △H=-30.98kJ/mol. 4. Key features of the UOP/HYDRO MTO process: (1) Fluidized-bed reactors and regenerators enable continuous and stable operation ； (2) The catalyst exhibits excellent shape-selectivity ； (3) The mass ratio of ethylene to propylene can be flexibly adjusted within a wide range (0.75–1.5), and the yield of ethylene + propylene remains relatively stable (around 80%) ； (4) The process raw material can be crude methanol or AA-grade methanol ； (5) The main products are olefins; light olefins with 97% purity can be obtained without installing ethylene and propylene separators, while polymer-grade light olefins can be obtained by using such separators. 5. Comparison between MTO and FCC technologies 5.1 Operating conditions In the MTO process, methanol conversion is carried out using a technique similar to the continuous reaction regeneration method used in the FCC process in the petroleum refining industry. A comparative analysis of the operating conditions between the MTO and FCC processes is shown in Table 1. As can be seen from Table 1, compared with the FCC process, the MTO process uses a single-component reactant, its products are simpler than those of the FCC process, the reaction temperature is lower, and the operational severity is reduced. Since the reaction in the MTO process is exothermic, an external heat extractor is also installed in the reactor of the MTO process. Table 1 Comparison of Process Conditions for MTO and FCC Processes | Parameter | FCC Reactor | MTO Reactor | FCC Regenerator | MTO Regenerator |
|-------------------------|---------------|-------------|--------------|----------------|----------------|
| Reaction Temperature/°C | 480–550 | 400–500 | 650–760 | 600–700 | |
| Reaction Pressure/MPa | 0.1–0.3 | 0.1–0.3 | 0.1–0.3 | 0.1–0.3 | |
| Type of Feedstock | Paraffin oil (mix) | Methanol (single component) | Air | Air |
| Molecular Weight of Feedstock | 200 | 28–33 | 28 | 28 | |
| Phase of Feedstock | Gas phase | Gas phase (with steam) | Gas phase | Gas phase |
| Reaction Products | Hydrocarbons and various impurities | Hydrocarbons/water | Flue gas | Flue gas |
| Molecular Weight of Products | Average of about 70 | About 23 | 30 | 30 |
| Nature of Reaction | Endothermic | Exothermic | Exothermic | Exothermic |
| Catalyst | Zeolite catalysts; SAPO-34 types | — | — | — |
| Average Particle Size/μm | 40–100 | Similar to FCC | — | — |
| Wear Resistance | Good | Similar or better | — | — |
| Fluidization Speed | High | Medium | Medium/Low | Low |
| Number of Commercial Units in Operation | Over 160 | Over 160 | — | — |
There are significant differences between MTO and FCC in terms of thermal balance. In catalytic cracking, the catalyst is lifted via inclined tubes and comes into contact with the feedstock; the contact time is quite different from that in FCC ； In a bubble column, the catalyst remains stationary, so the contact time is not particularly important for MTO; this allows for considerable flexibility in the design of MTO units. The first MTO plants were designed with large amounts of catalyst and long residence times, resulting in a one-pass conversion rate of nearly 100%. According to MTO technology experts at UOP, during the operation of the MTO process, the regenerator of this process can be completely removed to enable single-vessel coking, while the reactor can continue to receive feed and carry out reactions; this is a significant difference from the FCC process, where the two reactors cannot be completely separated from each other. The process flows of the MTO and FCC processes are basically the same; the main difference is that the MTO reaction is an exothermic reaction while the FCC reaction is an endothermic reaction, which requires the addition of external heat removal coils inside the reactor. An entity capable of undertaking FCC engineering design is fully capable of handling MTO engineering design as well. 5.2 Raw material products: The raw material products for the MTO and FCC processes are shown in Table 2. Table 2: Introduction to feedstocks and products of the MTO and FCC processes. Item: MTO; FCC. Feedstocks: Methanol (single-component); Paraffin oil (mixture). Products: Ethylene; Dry gas; Propylene; Liquefied gas; Mixed C4; Gasoline; C5; Kerosene; Gasoline; Diesel; Water; Oil slurry; Coke. 5.3 The appropriate internal pore structure size and solid acidity of the SAPO-34 catalyst enable reduced oligomerization of low-carbon olefins, thereby improving olefin selectivity. Compared with FCC catalysts, MTO catalysts possess the same resistance to thermal degradation caused by water vapor; moreover, they have better wear resistance, which reduces the likelihood of damage and is therefore very beneficial for minimizing catalyst consumption. During the prolonged testing period, the effects of various operating conditions on the catalyst’s performance were investigated to verify that the catalyst’s performance is reliable. Since the density, particle size distribution, structure, and other aspects of the catalyst are similar to those of FCC catalysts, its fluidization properties should also be similar. The impurities generated during the MTO reaction process are exactly the same as those in naphtha cracking units, and their concentration is relatively low; no new substances are formed. 6. Risk Analysis of the Industrialization of the MTO Process 6.1 Catalyst Consumption Given that at present, the only company offering commercial licensing for MTO technology is the U.S.-based company UOP, the MTO catalyst is the core of this process technology and also the key element through which the licensor generates commercial profits. According to UOP’s current pricing, the cost of catalysts is $70,000 per ton. According to data provided by domestic research institutions, if it is possible to produce MTO catalysts domestically, their price would be only about 20% of that of UOP’s catalysts. In China, institutions such as the Dalian Institute of Chemical Physics under the Chinese Academy of Sciences, the University of Petroleum, SINOPEC Research Institute of Petrochemistry, and Tsinghua University have all carried out research on MTO catalysts, achieving results comparable to those of UOP using laboratory-scale reactors. Currently, the Dalian Institute of Chemical Physics is conducting industrial demonstration tests with a methanol feed rate of 16,000 tons per year. Although extensive research has been conducted in China on MTO catalysts, there is still a certain gap compared to UOP in terms of the catalyst’s wear resistance and performance stability over long periods of operation; these two aspects are key to achieving domestic production of MTO catalysts. 6.2 Product Distribution The target products of the MTO process unit are ethylene and propylene, while the main by-products include mixed C4 and C5 compounds, gasoline, coke, and water. The factors that affect product distribution include the performance of the catalyst (activity and selectivity), operating conditions (temperature and pressure), and space velocity. Such data are currently available only from pilot plants; there are no data from industrial-scale operations to refer to. 7. Methods to reduce industrialization risks: (1) Draw fully on FCC experience to minimize design risks. To fully understand MTO technology and reflect it in the design process, it is crucial to select a design firm with extensive FCC design experience and a strong team of technical professionals. Currently, FCC technology is highly mature, with a large number of industrial plants in operation, and there are many engineering firms in China that have experience in related design work. (2) The patent licensor assumes some of the project risks. Since there are currently no industrial plants operating using the MTO process, the sharing of industrialization risks by the patent licensor should be given full consideration when purchasing the process package. Given the characteristics of this process, two approaches are recommended: one is to adopt the \"infinite repair method\", whereby it is agreed that within a certain time frame, if the plant cannot operate or operates abnormally due to issues with the process package, all costs associated with repairs required to restore normal operation shall be borne by the patent licensor ； Secondly, given the risks associated with the catalyst recovery system, for any loss of catalysts during the assessment period, the amount exceeding normal losses shall be covered and paid for by the patent licensor. (3) Construction of a small-scale industrial test facility: In accordance with the approval comments given by relevant officials from the National Development and Reform Commission regarding the introduction of MTO technology, a small-scale industrial test facility will be built. Once sufficient empirical data is obtained and the MTO technology has been fully validated, then a commercial-scale facility will be constructed in order to reduce investment risks. Based on this opinion, in order to verify the feasibility of the MTO technology in the short term, and considering the principles of short time required and low investment, it is appropriate to build a pilot plant with a capacity of 70–100 t/d. The main aspects that need to be verified include the reaction-regeneration section (including facilities for storing and feeding raw methanol, as well as for vaporization and superheating, the reaction-regeneration system, and the catalyst recovery system and other related components). This testing apparatus can be used for verification purposes as well as as a testing device for the future development of domestic catalysts. 8. Conclusions (1) The MTO process and equipment are basically the same as those of the mature catalytic cracking process and equipment in the refining industry ； The product separation process is also mature, and it is simpler than the processes and equipment used in naphtha cracking. (2) The scale-up from the demonstration unit to a 300,000 t/a ethylene plant is less than a thousand-fold; based on existing experience, computer simulation techniques, and modern engineering scale-up methods, this is entirely achievable.
|-------------------------|---------------|-------------|--------------|----------------|----------------|
| Reaction Temperature/°C | 480–550 | 400–500 | 650–760 | 600–700 | |
| Reaction Pressure/MPa | 0.1–0.3 | 0.1–0.3 | 0.1–0.3 | 0.1–0.3 | |
| Type of Feedstock | Paraffin oil (mix) | Methanol (single component) | Air | Air |
| Molecular Weight of Feedstock | 200 | 28–33 | 28 | 28 | |
| Phase of Feedstock | Gas phase | Gas phase (with steam) | Gas phase | Gas phase |
| Reaction Products | Hydrocarbons and various impurities | Hydrocarbons/water | Flue gas | Flue gas |
| Molecular Weight of Products | Average of about 70 | About 23 | 30 | 30 |
| Nature of Reaction | Endothermic | Exothermic | Exothermic | Exothermic |
| Catalyst | Zeolite catalysts; SAPO-34 types | — | — | — |
| Average Particle Size/μm | 40–100 | Similar to FCC | — | — |
| Wear Resistance | Good | Similar or better | — | — |
| Fluidization Speed | High | Medium | Medium/Low | Low |
| Number of Commercial Units in Operation | Over 160 | Over 160 | — | — |
There are significant differences between MTO and FCC in terms of thermal balance. In catalytic cracking, the catalyst is lifted via inclined tubes and comes into contact with the feedstock; the contact time is quite different from that in FCC ； In a bubble column, the catalyst remains stationary, so the contact time is not particularly important for MTO; this allows for considerable flexibility in the design of MTO units. The first MTO plants were designed with large amounts of catalyst and long residence times, resulting in a one-pass conversion rate of nearly 100%. According to MTO technology experts at UOP, during the operation of the MTO process, the regenerator of this process can be completely removed to enable single-vessel coking, while the reactor can continue to receive feed and carry out reactions; this is a significant difference from the FCC process, where the two reactors cannot be completely separated from each other. The process flows of the MTO and FCC processes are basically the same; the main difference is that the MTO reaction is an exothermic reaction while the FCC reaction is an endothermic reaction, which requires the addition of external heat removal coils inside the reactor. An entity capable of undertaking FCC engineering design is fully capable of handling MTO engineering design as well. 5.2 Raw material products: The raw material products for the MTO and FCC processes are shown in Table 2. Table 2: Introduction to feedstocks and products of the MTO and FCC processes. Item: MTO; FCC. Feedstocks: Methanol (single-component); Paraffin oil (mixture). Products: Ethylene; Dry gas; Propylene; Liquefied gas; Mixed C4; Gasoline; C5; Kerosene; Gasoline; Diesel; Water; Oil slurry; Coke. 5.3 The appropriate internal pore structure size and solid acidity of the SAPO-34 catalyst enable reduced oligomerization of low-carbon olefins, thereby improving olefin selectivity. Compared with FCC catalysts, MTO catalysts possess the same resistance to thermal degradation caused by water vapor; moreover, they have better wear resistance, which reduces the likelihood of damage and is therefore very beneficial for minimizing catalyst consumption. During the prolonged testing period, the effects of various operating conditions on the catalyst’s performance were investigated to verify that the catalyst’s performance is reliable. Since the density, particle size distribution, structure, and other aspects of the catalyst are similar to those of FCC catalysts, its fluidization properties should also be similar. The impurities generated during the MTO reaction process are exactly the same as those in naphtha cracking units, and their concentration is relatively low; no new substances are formed. 6. Risk Analysis of the Industrialization of the MTO Process 6.1 Catalyst Consumption Given that at present, the only company offering commercial licensing for MTO technology is the U.S.-based company UOP, the MTO catalyst is the core of this process technology and also the key element through which the licensor generates commercial profits. According to UOP’s current pricing, the cost of catalysts is $70,000 per ton. According to data provided by domestic research institutions, if it is possible to produce MTO catalysts domestically, their price would be only about 20% of that of UOP’s catalysts. In China, institutions such as the Dalian Institute of Chemical Physics under the Chinese Academy of Sciences, the University of Petroleum, SINOPEC Research Institute of Petrochemistry, and Tsinghua University have all carried out research on MTO catalysts, achieving results comparable to those of UOP using laboratory-scale reactors. Currently, the Dalian Institute of Chemical Physics is conducting industrial demonstration tests with a methanol feed rate of 16,000 tons per year. Although extensive research has been conducted in China on MTO catalysts, there is still a certain gap compared to UOP in terms of the catalyst’s wear resistance and performance stability over long periods of operation; these two aspects are key to achieving domestic production of MTO catalysts. 6.2 Product Distribution The target products of the MTO process unit are ethylene and propylene, while the main by-products include mixed C4 and C5 compounds, gasoline, coke, and water. The factors that affect product distribution include the performance of the catalyst (activity and selectivity), operating conditions (temperature and pressure), and space velocity. Such data are currently available only from pilot plants; there are no data from industrial-scale operations to refer to. 7. Methods to reduce industrialization risks: (1) Draw fully on FCC experience to minimize design risks. To fully understand MTO technology and reflect it in the design process, it is crucial to select a design firm with extensive FCC design experience and a strong team of technical professionals. Currently, FCC technology is highly mature, with a large number of industrial plants in operation, and there are many engineering firms in China that have experience in related design work. (2) The patent licensor assumes some of the project risks. Since there are currently no industrial plants operating using the MTO process, the sharing of industrialization risks by the patent licensor should be given full consideration when purchasing the process package. Given the characteristics of this process, two approaches are recommended: one is to adopt the \"infinite repair method\", whereby it is agreed that within a certain time frame, if the plant cannot operate or operates abnormally due to issues with the process package, all costs associated with repairs required to restore normal operation shall be borne by the patent licensor ； Secondly, given the risks associated with the catalyst recovery system, for any loss of catalysts during the assessment period, the amount exceeding normal losses shall be covered and paid for by the patent licensor. (3) Construction of a small-scale industrial test facility: In accordance with the approval comments given by relevant officials from the National Development and Reform Commission regarding the introduction of MTO technology, a small-scale industrial test facility will be built. Once sufficient empirical data is obtained and the MTO technology has been fully validated, then a commercial-scale facility will be constructed in order to reduce investment risks. Based on this opinion, in order to verify the feasibility of the MTO technology in the short term, and considering the principles of short time required and low investment, it is appropriate to build a pilot plant with a capacity of 70–100 t/d. The main aspects that need to be verified include the reaction-regeneration section (including facilities for storing and feeding raw methanol, as well as for vaporization and superheating, the reaction-regeneration system, and the catalyst recovery system and other related components). This testing apparatus can be used for verification purposes as well as as a testing device for the future development of domestic catalysts. 8. Conclusions (1) The MTO process and equipment are basically the same as those of the mature catalytic cracking process and equipment in the refining industry ； The product separation process is also mature, and it is simpler than the processes and equipment used in naphtha cracking. (2) The scale-up from the demonstration unit to a 300,000 t/a ethylene plant is less than a thousand-fold; based on existing experience, computer simulation techniques, and modern engineering scale-up methods, this is entirely achievable.
Unfortunately, there are no detailed process diagrams. . . .
This post was last edited by Feng1986 on 2011-7-13 at 10:15. In the case of applications involving new technologies, not to mention foreign technologies, even domestic ones cannot have their detailed manufacturing processes made public arbitrarily; the people of our country’s ability for \"independent innovation\" is evident to all! The revolution has not yet been successful; comrades must keep working hard! However, the two MTO and MTP units at Shenhua have now started producing products, and it is said that the performance is good.