Hydrogen peroxide to propylene oxide "out of the dragon"
Sinopec 15 years of research: hydrogen peroxide to propylene oxide technology implementation independent innovation
It took 15 years, and the investment in fixed equipment alone reached 1.28 billion yuan. The difficult process of Sinopec's hydrogen peroxide to propylene oxide project can be regarded as a microcosm of our country's basic and original independent innovation.
What is hydrogen peroxide to propylene oxide?
Fifteen years ago, Sinopec took the first step in hydrogen peroxide to propylene oxide. Since then, this project has been included in the "Ten Dragons" plan of Sinopec Science and Technology, and has become Sinopec's top scientific research project. Dai Houliang, chairperson and party secretary of China Petrochemical group company, has participated in the project review meeting many times to supervise the progress of the project. The importance is evident.
Where is the technology of hydrogen peroxide to propylene oxide? To figure this out, you must first understand propylene oxide. This is a professional term that non-professionals are confused about at first glance. As a basic petrochemical raw material, it is famous in the petrochemical industry, and it is the third largest acrylic derivative after polypropylene and acrylonitrile.
Chen Bin, deputy general manager of Sinopec Changling Refinery (hereinafter referred to as "Changling Refinery"), introduced that propylene oxide is widely used, mainly for the production of polyether polyols, propylene glycol and various non-ionic surfactants, such as polyether polyols, which are "one of the main raw materials for making polyurethane foam, thermal insulation materials, coatings, etc., and are used in refrigerators, air conditioners, and automobiles. It is very common in industrial production and daily life."
This is only a small part of the many uses of propylene oxide. In many industries such as chemical, textile, daily chemical, pesticide, etc., propylene oxide can often be seen, and it runs through almost all aspects of people's clothing, food, housing and transportation. With such a large and indispensable role, propylene oxide has been in short supply for many years, but the production of propylene oxide has always had problems such as high pollution and high danger.
He Chijian, director of the second research and development department of Hunan Changling Petrochemical Technology Development Co., Ltd., introduced that propylene oxide itself is a flammable and explosive chemical, and the chlorine gas used to produce propylene oxide by the chlorine alcohol method is a highly toxic gas. The production process has serious pollution to the environment, especially water. "To produce one ton of propylene oxide requires more than 40 tons of water, which consumes a lot of water, and at the same time produces more than 40 tons of chlorine-containing wastewater, which is extremely difficult to treat and has high environmental risks."
Foreign giants are at the forefront, can't they buy technology?
Currently, more than 80% of propylene oxide in China uses the chlorohydrin process. To this end, the national 2011 Industrial Structure Adjustment Catalogue clearly restricts the development of chlorohydrin process, and prohibits new chlorohydrin process plants from 2015. Other countries around the world have also forced the elimination of chlorohydrin-based propylene oxide production lines.
Both at home and abroad are exploring new methods of environmental protection and safety. International chemical giant BASF and German Evonik have taken the lead and have successively mastered the technology of hydrogen peroxide to propylene oxide. Chen Bin said, "This technology is called HPPO in the industry. It has very few by-products, less pollution, and less investment. The advantages are very obvious."
Since you have such a good technology, can't you just buy it? Indeed, Sinopec, the leader of our country's petrochemical industry, has had this idea, let alone other petrochemical companies.
However, with the monopoly advantage of international giants, the technology transfer price is extremely high. According to Sinopec insiders, Sinopec has discussed purchasing HPPO, and once negotiated, the other party's technology transfer fee for only the propylene oxide preparation part will cost tens of millions of euros.
More importantly, Chen Bin introduced, "Now the new production line of propylene oxide planned in China is basically based on HPPO technology." This means that if we rely on imported technology, our country may lose the voice over this basic petrochemical field.
After 15 years of research, in December 2018, Sinopec's "100,000 tons/year hydrogen peroxide production of propylene oxide complete technology development" project flew over Guanshan, and the technical appraisal concluded that Sinopec's "overall technology has reached the international advanced level, of which catalyst technology and material consumption have reached the international leading level". Sinopec became the third company in the world to master HPPO.
From original innovation to business operations, why is independent innovation difficult?
In 2004, Shu Xingtian, an academician of the Chinese Academy of Engineering, hoped to find a laboratory in China to explore the technology of hydrogen peroxide to propylene oxide.
In 2019, the project is expected to be officially put into business operations, which Sinopec internally calls "Dragon".
It is understood that as early as 1991, the then Petrochemical Corporation proposed to organize scientific research, design, production, equipment manufacturing, and construction for scientific and technological innovation, which was called "one-stop" joint research. At that time, 10 joint research projects were selected, which were called "Ten Dragons". Since then, "Ten Dragons" has become synonymous with key projects in Sinopec.
To develop a new preparation method for propylene oxide, Sinopec chose Changling Refinery as the lead unit. Chen Bin recalled that Changling Refinery took on the heavy burden of hydrogen peroxide to propylene oxide, first of all because within Sinopec, Changling Refinery has a reputation for attaching importance to research and development. Six technologies have been successfully applied in Changling Refinery for the first time in China, and five technologies have filled the domestic gap. In addition, the production of propylene oxide from hydrogen peroxide is in line with Changling Refinery's existing caprolactam-related technologies, and Changling Refinery took the initiative to go to Sinopec headquarters to fight for the project.
Unexpectedly, this work is a long 15 years, from the laboratory to the small test, pilot test, and then to the industrial transformation stage of the 100,000-ton project plant, even after the 100,000-ton project plant is running, it will take up to 4 years, in order to finally reach a stable state of operation, but also to announce the project officially "out of the dragon", external promotion.
"Every step was difficult," recalled Wang Wei, the party secretary of Hunan Changling Petrochemical Technology Development Co., Ltd., a private enterprise involved in the project. "At the beginning of the project, there was no information available internationally. It was like being in a dark room with no lights and no idea where to go."
The first hurdle was finding the right catalyst, which took almost a year. Wang Wei said that propylene is the raw material for making propylene oxide, which can chemically react with many catalysts to produce propylene oxide. The reaction will have countless forms, and it is very troublesome to choose and control. "BASF spent more than 10 years looking for catalysts. Even if it finds the right catalyst, the reaction of hydrogen peroxide with propylene may produce only a little propylene oxide, most of which is a by-product. It is necessary to pick sesame seeds in the sand, which is a lot of things in the petrochemical industry."
The test is the first step; the second step is the "small test", which is to scale up according to the laboratory effect; the third step is to continue to scale up according to the small test results, which is the "pilot test".
The real challenge is after the pilot test in 2012. Chen Bin said that on April 6, 2012, Dai Houliang, chairperson and party secretary of China Petrochemical group company, instructed that the project should be advanced as soon as possible to form a complete set of HPPO technology that can be commercialized and replicated.
Changling Refining Chemical decided to launch a 100,000-ton HPPO project plant with an investment of more than 1.20 billion yuan. At this time, Sinopec's R & D model showed a strong advantage.
In 2018, the state proposed to promote the integration of production, education, research and application, support leading enterprises to integrate the strength of scientific research institutes and universities, and establish innovative consortia. "We have relied on such innovative consortia to make our own HPPO technology." said Wang Miaoyun, chairperson, party secretary and general manager of Changling Lianhua.
The HPPO project can be called a high-risk project. Hydrogen peroxide is very active, propylene is explosive, and two very dangerous things are put together. "If the process is uncontrollable, it is very easy to explode." He Chijian said that in China, there are very few hydrogen peroxide production enterprises that have not had an explosion accident. In the middle and late stages of the project, the Changling Refining Hydrogen Peroxide to Propylene Oxide Project also had a safety accident. "At that time, the blow to everyone was relatively large, and I felt a lot of pressure, but the leadership firmly supported it and continued to work."
On December 6, 2014, with a total investment of 1.28 billion yuan, the first domestic 100,000-ton/year HPPO plant with independent intellectual property rights was completed and put into operation successfully. In April 2015, the 150,000-ton/year hydrogen peroxide plant of the Changling Refining Propylene Oxide Project was completed and put into operation.
At the end of 2018, the Changling Refining Propylene Oxide Plant completed the high-load operation calibration test, and the purity of the propylene oxide product was stable at over 99.95%. The product quality reached the national high-quality product standard, and the technology entered the stage of maturity and promotion.
Wang Miaoyun introduced that Changling Refinery, which has an annual output value of nearly 50 billion yuan, will focus on the utilization of propylene oxide and aromatic fractions in the chemical industry in the future, expand the capacity of propylene oxide plants, extend polyether and other characteristic chemical downstream industries, and strive to basically complete the industrial structure adjustment and transformation and upgrading around 2025.
In addition to Changling Refinery itself, Sinopec also plans to build a 200,000-ton hydrogen peroxide-to-propylene oxide project in Fujian. "There are many companies who come to learn and negotiate," Chen Bin said.
Data show that from 2014 to 2018, the growth rate of propylene oxide production capacity in our country changed from high speed to flat, with a 5-year compound annual growth rate of 5.2%. The traditional chlorohydrin process that is not environmentally friendly is not allowed to be rebuilt, and propylene oxide is still in short supply.
Expert Reviews
Wang Xieqing, Academician of Chinese Academy of Engineering: Hydrogen peroxide to propylene oxide complete technology will have an important impact
At present, the industrial methods for producing propylene oxide include the chlorine alcohol method, the co-oxidation method and the direct oxidation of hydrogen peroxide.
The chlorohydrin method has low conversion rate, large chlorine consumption, serious equipment corrosion, and serious pollution. The production of 1 ton of propylene oxide produces 2 tons of waste residue and 40-80 tons of chlorine-containing wastewater. Most domestic propylene oxide is produced by this method. Due to serious environmental pollution, new plants are no longer allowed, and existing plants are also facing the dilemma of phasing out. It has been listed as a restricted category in the "National Industrial Structure Adjustment Guidance Catalogue 2011". The co-oxidation process is complicated, the process is long, the equipment requirements are high, the investment is large, and the by-products are large, and there is pollution, especially restricted by the joint product market.
A lot of manpower and material resources have been invested in the research of new methods for the production of propylene oxide without pollution and low cost at home and abroad. The direct oxidation of hydrogen peroxide to synthesize dioxypropane (HPPO) technology jointly developed by Changling Refining Chemical, Sinopec Group Petrochemical Research Institute and Hunan Changling Petrochemical Technology Development Co., Ltd. for 15 years has broken the international monopoly and filled the domestic gap. The process has the characteristics of mild conditions, simple process flow, good product selectivity, high atomic utilization rate and environmental friendliness. The HPPO process is an internationally recognized green and environmentally friendly production technology. It will become the main process used in new propylene oxide projects and is the development trend of propylene oxide synthesis technology.
Sinopec Group's self-developed complete set of hydrogen peroxide to propylene oxide technology has been authorized 17 invention patents, including 12 foreign patents. The technology has passed the Sinopec Group technical appraisal and has significant innovation and independent intellectual property rights. The overall technology has reached the international advanced level, including catalyst technology and material consumption.
