Wang Xiaoyun, Deputy Secretary of the Party Committee of China Chemical Industry News: This year is the closing year of the "13th Five-Year Plan", and the "14th Five-Year Plan" will soon be ushered in. At present, the petrochemical industry is in a critical period of transformation and upgrading. We believe that when discussing the development of the propylene oxide industry chain, we should focus more on the country's strategic considerations of vigorously promoting high-quality development and building a new pattern of "dual cycles". Propylene oxide is a petrochemical product that the state encourages the development of. With the acceleration of the localization of production processes and the acceleration of large-scale application, the industry's production capacity has expanded rapidly, and innovations have emerged one after another.

Therefore, standing on the commanding heights of industry development and closely following "technical innovation and green development" have become the two major focus elements of this forum. The forum will focus on advanced production processes, especially co-oxidation and hydrogen peroxide direct oxidation and related supporting technologies in the industry chain. It will discuss the technicality and economics of the new process, as well as the development of hydrogen peroxide technology supporting the HPPO method; exchange information on new projects Operating experience, analyzing the development trend of polyether and polyurethane industries, and discussing the growth potential of downstream markets such as PPC plastics and propylene glycol ethers, in order to promote the technological progress and sustainable development of the upstream and downstream industrial chain of propylene oxide, and expand market development and application.

Wu Feike, deputy general manager of Changzhou Ruihua Chemical Engineering Technology Co., Ltd.: As we all know, the chlorohydrin method, the traditional technology of propylene oxide production, has mature technology and low investment, but it has serious pollution. For every ton of propylene oxide produced, about 40-50 tons of saponification wastewater and 2-4 tons of waste residues are produced. These wastes are difficult to deal with and costly, and cause serious environmental impacts. In contrast, the indirect oxidation method can solve the shortcomings of the severe pollution of the three wastes of the chlorohydrin method, equipment corrosion and the need for chlorine, and can produce a large number of co-products. Its industrial process is long, equipment investment is large, and it has good economic benefits. Therefore, in the "Industrial Structure Adjustment Guidance Catalog" issued by the National Development and Reform Commission, "200,000 tons/year and above co-oxidation propylene oxide plant" is listed as an encouraged project.

Ruihua's isobutane co-oxidation method uses a reaction network of isobutane oxidation, propylene epoxidation and tert-butanol dehydration. Compared with the traditional ethylbenzene oxidation, pure oxygen is used as the oxidant, the decomposition reaction order is higher, the activation energy is closer to the activation energy of the oxidation reaction, the decomposition reaction is more significant, and the selectivity is higher. At present, the reactors of each step in the reaction network have the characteristics of safe process, simple operation, and low environmental risk. Ruihua's independent catalytic technology and epoxidation process design have also improved the entire process based on the company's own requirements.

At present, Ruihua's isobutane co-oxidation process has achieved plant scale and material balance. At present, this method produces 280,000 tons of propylene oxide and 550,000 tons of isobutylene per year, and the energy consumption is reasonable. The produced isobutylene has high purity and low impurity content, and has good economic prospects.

Wei Xiaobo, a professor-level senior engineer at the Luoyang Institute of Technology of Sinopec Refining and Chemical Engineering (Group) Co., Ltd.: Continuous flow ionic liquid catalyzed the production of propylene oxide by hydrogen peroxide, which is a microreactor and process technology research and development platform of the Luoyang Institute around the R&D center The green propylene oxide production technology launched is of international leading level. The technology uses a new type of ionic liquid catalyst developed by East China University of Science and Technology, and is planned to be developed by the Shanghai Engineering Company of Sinopec Refining and Chemical Engineering Group.

The technology will be a global original propylene epoxidation technology with independent intellectual property rights. After successful development, this technology will be an internationally leading technology. It will be composed of East China University of Science and Technology, SEG Luoyang Technology R&D Center, engineering design unit, industrial test application and other parties. All parties will share intellectual property rights in accordance with the technology agreement. rights and interests. If the project is successfully developed, the application prospects are very good. The peroxoate ionic liquid catalyst used in the process carries out the homogeneous reaction of liquid HPPO, and the oxidation reaction activity is high, and the catalyst and the product are easy to separate after the reaction. In addition, the ionic liquid catalyst has the characteristics of high stability (decomposition temperature greater than 150°C), and can efficiently catalyze the epoxidation reaction of various enols and olefins under extremely mild conditions (0°C to 60°C). This route can solve the problems of difficult heat extraction of solid TS molecular sieve catalyst and frequent catalyst regeneration, and the industrialization of this technology can be realized through a microreactor. Both the catalyst and the solvent can be recycled, and the replacement and regeneration of the catalyst are very easy.

The exploratory experiment results that have been completed so far show that the catalyst used in the process has good thermal stability and high product purity. In the future, we will strive to achieve 98% hydrogen peroxide conversion rate, 99% PO selectivity, over 90% production rate, and catalyst life exceeding 6 months. We will strive to complete medium-scale tests and complete technical applications in 2022.

Supporting coordination requires both quality and quantity

Shen Chong, deputy director of the hydrogen peroxide technology development department of Liming Chemical Research and Design Institute Co., Ltd.: The HPPO process requires high quality hydrogen peroxide. However, industrial hydrogen peroxide usually contains a certain amount of impurities such as organic matter, metal ions and their salts. These impurities will be deposited or adsorbed on the active surface and pores of the TS-1 catalyst, and ring-opening by-products are easily formed under acidic conditions, resulting in reduced catalyst selectivity. At present, there are technical indicators for the content of hydrogen peroxide organic carbon and phosphate in China, but the content of alkali metals, alkaline earth metals, anions, etc. have not been tested. The impact of the quality of raw hydrogen peroxide on the HPPO process and the quality of PO products is unclear.

Liming Institute uses the anthraquinone method to produce hydrogen peroxide and is the founder of this method. This method is currently the only industrialized hydrogen peroxide production method. At present, Liming Institute adopts improved second-generation technology, using high-efficiency palladium catalyst fixed-bed hydrogenation process to improve hydrogen efficiency and production scale. The scale of many devices using Liming Institute's production technology has reached 300,000 tons per year.

At present, Liming Institute has multiple sets of different hydrogen peroxide process technologies, and there are differences in project investment, production costs, and product quality requirements. The operation of the equipment is safe and stable. According to the requirements of the enterprise, Liming Institute relies on its own research and development strength to design multiple sets of different solutions. The high-capacity TBU three-solvent working fluid system has high hydrogen efficiency, large production capacity, good product quality and stable and safe equipment. The new high-efficiency palladium catalyst has less filling, less investment, high hydrogen efficiency, large production capacity, low palladium loss, low EAQ consumption, and catalyst Long life, combined use will help companies reduce costs and increase efficiency. Vacuum dehydration, alkali tower regeneration, and clay bed regeneration systems ensure low water content in the working fluid, high regeneration efficiency of degradation products, stable working fluid components, and device safety and stability. In turn, the strict quality requirements of the hydrogen peroxide of the HPPO method are ensured.

Shen Xiaoyan, China Business Manager of Solvay Investment Co., Ltd.: Solvay is a global leader in peroxide production, and peroxide is a green product with increasing demand. On the basis of peroxide production, Solvay also has the most advanced HPPO production process in the world.

At present, Solvay has three single-set plants with an annual output of more than 300,000 tons in the world. They are located in Antwerp in Belgium, Mata House in Thailand and Dubai in the UAE. They all adopt the form of upstream and downstream cooperation. Solvay is responsible for hydrogen peroxide. In part, the partner is responsible for propylene oxide operations, but the technology comes from Solvay. The Antwerp plant is Solvay's first HPPO production unit in the world, and it was put into use in 2008. The Thai installation went into production in 2011, and the Dubai installation went into production in 2017. The three sets of mature technologies and operations benefit from Solvay's expert team. From design engineering to project management, technical management, process management and operation, all of them come from the company.

Solvay's installations are safe and reliable. Large-scale installations have no safety accident records for more than ten years. The internal OEE efficiency continues to maintain at 98-99%, and the product quality has more than 10 years of performance verification. The plant is compact in design, occupies less space than other solutions, consumes less steam and electricity, and the wastewater is biodegradable and has no solid waste discharge. Under the same safety and environmental protection standards, the cost is lower.

Strengthen scientific and technological support to promote industrial development

Li Yiming, Project Manager of Beijing Branch of China Huanqiu Engineering Co., Ltd.: China Huanqiu Beijing Branch has carried out overall design, basic design, and basic design for Zhejiang Petrochemical Co., Ltd.'s 270,000 tons/year propylene oxide and 600,000 tons/year styrene monomer projects. Detailed design, procurement of technical services and on-site technical services.

The project has the characteristics of a long PO/SM device process, a complex process, and a variety of process units. In terms of the number of equipment, the device includes towers, reactors, heat exchangers, air coolers, tanks, pumps, compressors, industrial furnaces, etc. There are more than 700 sets, the quantity is large; the utility consumption is also large, including high-pressure steam, circulating water, instrument air, nitrogen, power consumption, etc., with a large number of IO points and large flare emissions, so a separate oxygen-containing flare system is required. Based on these characteristics and considering that this is the first engineering application of 270,000 tons of PO, the company has professionally designed the reaction device and equipment. And organized a number of special seminars and expert meetings, organized various related professional personnel and company experts to discuss and resolve.

These design ideas make the design of some devices special. For example, in the high vacuum condenser, due to the high operating vacuum of the second rough tower condenser, the allowable pressure drop is small, and the conventional design may have vibration, large pressure drop, and fail to meet the process requirements. Case. To this end, the company specifically optimized the design, adding baffles by changing the type of heat exchanger and the feeding direction of the nozzle. It can solve the sound vibration and mechanical vibration in operation. Not only the pressure drop is small, but the uniform fluid distribution also improves the heat transfer effect. The actual pressure drop is reduced to below 2KPa, the equipment investment is reduced by 32.7%, and the heat transfer effect is increased by 41.8%. For other specific processes such as the support type of the secondary concentration tower and the comparison and selection of air cooler schemes, the company has come up with targeted professional designs.

At present, the basic design of the project package has been completed, and the detailed design is expected to be completed in August next year.

Tan Xi, Manager of Marketing Development Department of Xiangyang Hangli Electromechanical Technology Development Co., Ltd.: "Safety, high production, consumption reduction, energy saving, and emission reduction" is the eternal theme of chemical plant production management, and they have also given birth to the development and application of various related new technologies. . Xiangyang Hangli Electromechanical Technology Development Co., Ltd. has successfully developed a turbo-refrigeration power generation system that integrates consumption reduction, energy saving, emission reduction, and efficiency enhancement functions. It has been successfully operated in the exhaust gas treatment of domestic chemical plants. Currently, the turbo expansion produced by Hangli Refrigeration units and turbo-refrigeration power generation systems have been used in the installations of more than 130 chemical companies at home and abroad.

The traditional system has the problem of whether the pressure contained in the exhaust gas can be fully recycled. The work done by the exhaust gas through the shaft is only used for braking at the compressor end, and no benefit is produced. Therefore, how to maximize the use of the residual pressure of the exhaust gas and convert the discharged energy into benefits has become a point of question for research and development. For this reason, "Hangli Electromechanical" has successively developed two different structures of systems with expander coaxial direct-connected high-speed power generation and coaxial deceleration power generation, and they have been successfully operated in chemical production equipment to achieve simultaneous cooling and power generation. The residual pressure energy of the exhaust gas is converted and utilized.

In the upgraded expansion, refrigeration, power generation and grid-connected integrated machine system, the design principle is to ensure the refrigeration function, maximize the cold capacity to condense aromatic hydrocarbons or other condensable solvents, and recycle the shaft power to generate electricity.

The turbo refrigeration power generation system is an energy-saving and emission-reduction equipment integrating refrigeration and power generation functions. At present, a single set of equipment processes the exhaust gas flow rate of 5000-65000Nm³/h, the exhaust gas pressure is 0.1-10MPa, and a single unit can generate up to 2MW. The product uses the residual pressure of the chemical exhaust gas to expand to do work. While the refrigeration exhaust gas is condensed to recover organics, it generates electricity and connects to the grid for its own use, realizing double benefits. Taking 20000Nm³/h hydrogen peroxide tail gas as an example, the use of expansion refrigeration power generation system can save 95% of cooling power consumption and realize energy-saving power generation of 260KW.

Ding Leijiang, Senior Account Manager of UOP Global Oil Process Technology Co., Ltd.: There are many kinds of propylene oxide production processes, and the industrial wastewater produced is not the same. The existing treatment process produces a large amount of salt-containing wastewater, which is characterized by high salt, high organic matter and high calorific value organic waste liquid. Under the current technical conditions, these pollutants are very difficult to deal with. At present, there are about three main wastewater treatment methods, namely, acid oil production-biological oxidation method, WAO high temperature wet oxidation biochemical method and direct high temperature thermal oxidation method. Among them, the direct high-temperature thermal oxidation method currently used still has some problems. For example, where molten salt comes into contact, it can cause corrosion problems, such as near the nozzle of salty wastewater, and cause blockage of some channels.

To this end, UOP has developed a variety of solutions, including new refractory materials, burner structure improvements, CFD flow field design, wastewater atomization and flue gas quenching equipment. Among them, the structure of the combustor is improved, so that the combustor has the characteristics of no swirling parts, and all exhaust gas and waste liquid are injected axially to the furnace as much as possible. The flue gas quenching and dry slagging solution eliminates the strong local corrosion in the molten pool and the molten bath, and the linear combustion causes the lining of the furnace to burn up and reduces the corrosion. Finally, the boiler fouling is weakened and the dust is easier to clean.

Yang Chunhe, Technical Director of Sinopec Nanjing Engineering Co., Ltd.: The co-oxidation of propylene oxide with ethylbenzene to produce propylene oxide and co-production of styrene (POSM), usually ethylbenzene is oxidized to ethylbenzene peroxide under certain temperature and pressure with air Hydrogen is then epoxidized with ethylbenzene hydrogen peroxide and propylene to produce propylene oxide and co-produce styrene. However, the pressure of the ethylbenzene oxidation reaction is not high, the reaction is exothermic, and a large amount of heat will be released during the reaction. Under low pressure, part of the ethylbenzene vaporizes and evaporates, taking away part of the heat, and the remaining heat needs to be removed by heat exchange to maintain the reaction temperature of the reactor.

In addition, the above-mentioned ethylbenzene oxidation tail gas contains evaporated ethylbenzene, nitrogen, unreacted oxygen, water, light components, etc. The temperature of the ethylbenzene oxidation tail gas is usually 130-150℃, the pressure is 0.2-0.5MPa, and the oxidation tail gas flow rate It is relatively large and contains high heat. It is of great significance to effectively recover the heat of the oxidation tail gas.

Sinopec Nanjing Engineering Co., Ltd. used the technology provided by Changzhou Ruihua Chemical Co., Ltd. to design the POSM project. The oxidation tail gas heat recovery technology has many original defects, such as insufficient recovery and high steam and water consumption. After using the new technology process, the heat recovery effect has been greatly improved: the light components and water in the circulating ethylbenzene are not easily brought into the oxidation reactor, reducing slagging and extending the operation period of the device; circulating ethylbenzene into the ethylbenzene oxidation reaction In front of the reactor, it is directly mixed with the oxidation tail gas for heat exchange, and the heat recovery of the oxidation tail gas is sufficient; the amount of heating steam before the circulating ethylbenzene enters the ethylbenzene oxidation reactor is small; the oxidation device has strong adaptability to load fluctuations; the device has a high online rate; the tail gas heat exchange is eliminated The heat exchanger used is liquid heat exchange, with large heat transfer coefficient and small heat exchanger area; low consumption of circulating cooling water and preheating hot water; the overall benefit is that the ethylbenzene oxidation conditions are optimized and the oxidation tail gas energy recovery efficiency is high , The consumption of public works is small. This system is very suitable for large-scale installations, and may further optimize the subsequent process ethylbenzene recovery process, shorten the process, and further reduce energy consumption. The energy consumption of the new technology per ton of styrene product is 9.802 kg of standard oil less than the existing technology, and the energy consumption of the new technology per ton of propylene oxide product is 24.5kg of standard oil less than the existing technology. With the new technology of 200,000 tons/year styrene co-producing 80,000 tons of PO, the annual economic benefit is about 12.492 million yuan. If it is used for 600,000 tons/year styrene co-production of PO, the annual energy saving benefit will exceed 37 million yuan.

Exploring new paths to empower industry transformation and change

Zhou Xinggui, professor of East China University of Science and Technology: At present, the four main methods of producing propylene oxide have their shortcomings, and there are major needs for new PO production technologies that are environmentally friendly, energy-saving, and low-cost.

In 1998, Japan reported the propylene hydroxide epoxidation of propylene oxide and developed the first generation of gold-titanium catalyst. In 2012, gold-isolated tetravalent titanium catalysts were reported. This kind of catalyst has high activity and good selectivity. The formation rate of propylene oxide is significantly improved, and the reaction selectivity is high. It has the same activity and selectivity as the industrial ethylene epoxidation method, and basically meets the requirements of industrial production for the space-time yield of the catalyst. The method has other advantages. It adopts a one-step reaction and can use a fixed-bed reactor with low investment; there is no solvent in the reaction process, and the boiling point of the product and the raw material is different, and it is easy to separate; the reaction temperature is 180-220℃, and the reaction heat can be generated Medium pressure steam is used for product separation. If it can be industrialized, it is an environmentally friendly and economical process.

However, this method currently has some shortcomings. In terms of catalysts, it also has the disadvantages of difficult to balance conversion rate and selectivity, low hydrogen efficiency and poor stability. The reaction has many side reactions and complicated mechanism. The current frontier research focuses on improving catalyst deactivation, reaction kinetics and explosion limit prediction.

Liu Zhun, general manager of Jiangsu Yida Chemical Co., Ltd.: This year, the entire propylene oxide market is in an explosive market, with the highest price reaching 19,000 yuan/ton, which is the highest since 2008. This price is due to the surge in demand and prices for downstream polyether polyols, which triggered a surge in the price of propylene oxide. I personally understand that it is not normal for the price to reach 19,000 yuan/ton. In fact, the price of propylene oxide has gradually decreased on the basis of 19,000 yuan/ton recently. At present, the price of propylene oxide is also around 15,000 yuan/ton, but the price of propylene oxide is 10,000 yuan/ton, which is a more reasonable price.

Enterprises that invest in propylene oxide must invest in propylene oxide projects from the perspective of their own strength and their own raw material advantages, market advantages, and regional advantages.

Yang Xianghong, a senior expert in the petroleum and chemical industry: This year we have witnessed history: Propylene oxide has set a new high since 2012, and once touched 18,900 yuan/ton; since September, production companies have maintained ultra-high profits of more than 9,000 yuan/ton; The downstream rally was even more frantic. Polyether broke an 11-year high, and the market price of dimethyl carbonate broke through 14,000 yuan/ton. Although the market price of propylene oxide has begun to fall, this wave of crazy market has attracted great attention from the chemical industry, because a large wave of frightening new production capacity is on the way.

From the perspective of the industrial chain, the raw material of propylene oxide is propylene, and the excess capacity of propylene is a foregone conclusion. In 2019, my country's propylene production capacity will reach 40 million tons/year, and in the future, propylene production capacity not less than this number is coming. By 2025, my country's propylene production capacity will exceed 84 million tons per year. In terms of propylene oxide, due to considerable profits and market demand, it has attracted a large number of new entrants, and undertaking the pressure from the upstream of propylene, the industry is in an expansion trend. In the case of increasing dependence on imports, my country's current planned propylene oxide production capacity under construction exceeds 8.7 million tons per year, and a serious excess of basic propylene oxide production capacity is a foregone conclusion. However, in the next five years, the global PO market demand growth rate will not exceed 3%, China may reach 4%, which means that there is a serious overcapacity, and the production of products is seriously homogenized. This almost means that the price war of propylene oxide is about to break out.

In the downstream, the industry with the largest number of propylene oxide customers and the largest demand is the polyether polyol industry. The number of other chemical downstream companies is not large, and the willingness to expand capacity is not high. The future expansion prospects of isopropanolamine, flame retardants, cellulose, additives and other industries are also not ideal. In the future, the main downstream consumption growth of propylene oxide will still be concentrated in the polyether polyol industry. It is estimated that the production capacity of polyether polyol will increase to 10 million tons per year in 2025, which can consume 3.45 million tons of propylene oxide per year. However, companies cannot focus their growth on polyether polyols, but in emerging high-end areas such as polyurethanes, surfactants, and polyether amines.

Ni Ji, a senior analyst at Orient Securities: At present, the propylene oxide market is in short supply. The reason for this problem is that the three main domestic processes have different problems, which once affected the expansion of production. After 2015, the growth rate of domestic PO supply decreased significantly. However, the demand side has been growing rapidly. Even if this year is affected by the epidemic, the performance of traditional demand is still relatively good. The addition of mattress anti-dumping and other factors has caused domestic propylene oxide to be in short supply and prices soaring.

However, the propylene oxide industry is ushering in an inflection point. At the technical level, the industry is also favorable. The co-oxidation technology monopolized by overseas companies is expected to be broken by domestic companies. This has led to the commissioning of multiple co-oxidation production units and the rapid increase in market volume. Even if the HPPO production capacity is not considered, the domestic propylene oxide production capacity will reach 4.7 million tons by 2022, an increase of 38% compared to the current one. This will lead to a decline in the industry's average operating rate after 2020. The new co-oxidation method is on the right side of the cost curve. When the new demand is not as good as the new supply, the industry will enter a violent right-side extrusion process.

When it comes to fighting costs, it is necessary to compare the economics of various processes. At present, the cost of the chlorohydrin method is continuously increasing, the HPPO method is the lowest, and the co-oxidation method is 2500-3000 yuan/ton. In addition, in terms of profitability, the profitability of the co-oxidation method is the best. Although the operating cost of the HPPO method is low, the oxidizer is expensive, and there is no amortized cost of by-products, which restricts its profitability.

Dr. Zong Hongliang, Senior Engineer, Jiangsu Zhongshan Chemical Co., Ltd.: The continuous advancement of propylene oxide technology affects the future of polyols, because it is a high-cost component, and most of the propylene oxide producers are still the main ones Polyether polyol producers, so all changes in the propylene oxide market will directly affect polyol producers and downstream users of polyols.

Polyether polyols are a series of high molecular compounds containing ether bonds in the molecular chain made by ring-opening polymerization of epoxides. They can be divided into 3 categories according to polymerized monomers. Among them, the polymer obtained by ring-opening polymerization of lower alkylene oxide monomers such as propylene oxide or ethylene oxide using active hydrogen-containing compounds such as polyols or polyamines as initiators, they are collectively referred to as PPG, which is used The widest range of polyether polyols.

At present, my country's polyether polyol industry has the characteristics of large industrial scale and obvious overcapacity; relatively low technical level, low technological differentiation, serious homogeneity of low-end products, fierce market competition, and low market share of high-end products.

However, polyether polyols are widely used, soft foam is a common home decoration material, high resilience polyether is used in car interiors, and shoe material polyether is used in shoe production. Among several high-end polyethers, foams made from slow-resilient polyethers have the functions of shape memory, energy absorption, sound absorption, and shock absorption, and are used as shock absorbers, sound absorbers, and shock absorbers; rigid foam polyethers are mainly used for preparation Rigid polyurethane foam; elastomer polyether is suitable for polyurethane elastomers, coatings, adhesives, sealants, etc.

Polyether polyols are widely used, and my country is also the world's largest polyurethane production and consumption area. At present, the industry has entered a period of new development and improvement. High-quality environmental protection and sustainability are its development directions. It can be said that this industry has many development directions. Only by taking the high-end route can we avoid homogeneous competition.

This forum was co-organized by China Chemical News Agency and Changzhou Ruihua Chemical Engineering Technology Co., Ltd., and co-organized by Jiangsu Yida Chemical Co., Ltd. and China Huanqiu Engineering Co., Ltd. Beijing Branch. The number of participants was nearly 200. The forum carried out in-depth discussions on the theme of "Technical Innovation and Green Development", presenting a nutritious technological feast for the industry. (Photo: Xue Qinghai Video: Han Jie)