In the early 1970s, China imported a large number of advanced petrochemical plants, and it is urgent to develop catalysts suitable for these imported plants. Under the guidance of Professor Tang Youqi, in 1974, Xie Youchang and a group of "workers, peasants and soldiers" went to Beijing Institute of Chemical Technology to jointly develop ethylene oxychlorination catalysts suitable for imported large-scale fluidized bed devices. At work, dozens of people take turns to carry out the pilot test of fluidized bed, but there is a great debate about whether this pilot test can solve the problem. At that time, a catalyst had been developed in China, and its activity was much higher than that of imported catalysts. However, after the pilot test, people still feel uncertain whether this catalyst can be used in imported equipment. Because the imported large-scale industrial fluidized bed is12m high and 2.8m in diameter, there are many cooling pipes in it, while the pilot bed is only an empty pipe with a height of1.5m and a diameter of10cm. In the pilot test, temperature, pressure and feed gas composition can simulate the production device, but it is impossible to simulate the production device with linear speed and airspeed at the same time. The fluidization state in the production equipment is even less likely to be simulated in a much shorter pilot plant with a much smaller diameter. Therefore, it is not necessarily good for a good catalyst to be used in a large-scale industrial plant in a fluidized bed pilot plant. Therefore, Xie Youchang suggested reducing or even canceling the fluidized bed pilot test, focusing on the pilot study of catalyst kinetic performance and the pilot scale-up of catalyst preparation. He believes that compared with imported catalysts, the activity of the developed catalysts should not be too high or too low. Because too high will produce too much reaction heat, which will make the bed temperature too high and increase the side reaction; If it is too low, the conversion rate of raw materials is not enough. He proved through small-scale experiments that the activity of the catalyst originally developed was too high, and the CO2 side reaction produced by ethylene combustion was very serious when the imported device worked at low altitude and low speed. He pointed out that as long as the dynamic performance (activity and selectivity) of the developed catalyst is similar to that of the imported catalyst, and the key physical properties affecting the fluidization state, such as mechanical strength, specific gravity and particle size distribution, are also similar, it can be used instead of the imported catalyst in the imported device. Later practice proved that this route was correct, and the oxychlorination catalyst suitable for imported devices was successfully prepared. After leading the "students of workers, peasants and soldiers" to complete the development of oxychlorination catalyst, they were sent to 1976 to lead the students of workers, peasants and soldiers to "open a museum" in Tibet to study the sulfur dioxide fluidized bed roasting technology of local sulfur-poor mines in a small sulfuric acid plant.
In the 1990s, there was an international upsurge of studying nano-materials. In view of the high manufacturing cost of general nano-oxide powder and the defects that nano-oxide powder is easy to agglomerate and produce holes when sintered into nano-ceramics, Xie Youchang proposed to prepare nano-oxide particles by gas-phase hydrolysis with cheap and volatile metal oxides such as SiCl4 _ 4, TiCl4 _ 4, ZrCl4 _ 4, SnCl4 _ 4, AlCl3 _ 3 and FeCl3 _ 3 as raw materials. This kind of nano-oxide particles rarely agglomerate, with high purity, narrow particle size distribution and easy size adjustment. We also found that all ZrO2 _ 2 nanoparticles can be controlled to be stable in tetragonal phase by using Y2O3 dispersed in a monolayer. This nano-oxide powder can be sintered at 1 150℃ to a theoretical density of more than 98.5%, which is lower than the sintering temperature reported in the literature by more than 100℃, and may become an important raw material for plastics and ceramics. The preparation technology of nano-zirconia powder has been patented.
Oxygen is widely used in industry, and pressure swing adsorption air separation is a technology developed in 1970s. A new adsorbent for air separation and oxygen production-low Si/Al ratio lithium ion exchange X molecular sieve (LiLSX) was developed abroad, which greatly improved the efficiency of pressure swing adsorption air separation and reduced the cost of oxygen production. However, foreign companies monopolize this adsorbent and only sell it to China together with pressure swing adsorption equipment, which is very expensive. The preparation of this adsorbent is very difficult. Firstly, the molecular sieve (Na, K)LSX with low Si/Al ratio was synthesized, which contains a lot of sodium and potassium ions and needs to be exchanged with lithium ions to become LiLSX. Lithium ion is the most difficult ion to exchange on molecular sieve among alkali metal ions. According to foreign patent documents, in order to obtain LiLSX molecular sieve with exchange degree over 99%, it is necessary to carry out five times of ion exchange, with an excess of 6.3 times each time. The utilization rate of lithium ion is very low, the loss of separation and recovery is great, and the production cost is very high. In order to solve this problem, Xie Youchang's research group invented a new process of high-efficiency ion exchange in suspended bed, which greatly improved the utilization rate of lithium and greatly reduced the production cost. Therefore, Peking University Resources Group invested in the establishment of Peking University Pioneer Company to industrialize this technology. Now the production equipment has been built, and the product high-efficiency air separation oxygen adsorbent has reached the international advanced level. It has been successfully applied to large-scale pressure swing adsorption air separation oxygen production equipment, and its performance is not inferior to that of imported equipment, and its cost performance is much higher than that of similar foreign products. It has strong international competitiveness and has begun to export.
Xie Youchang has been engaged in teaching and scientific research for more than 40 years. He believes that university teachers should combine teaching with scientific research. Grasping solid basic knowledge and theory in teaching is of great benefit to scientific research, which can constantly update the teaching content. Therefore, while doing a lot of scientific research, he never stopped teaching. He has taught two basic courses, physical chemistry and structural chemistry, as well as postgraduate courses in surface structural chemistry. In cooperation with Comrade Shao Meicheng, he was entrusted by the Ministry of Education to compile the Textbook of Basic Courses of Structural Chemistry, which was published in 1979 for college students who resumed the college entrance examination after the Cultural Revolution. This book is characterized by few but precise, accurate expression of basic concepts, simple explanation of difficult points, and close combination of theory and practice, which is well received by readers.
Besides teaching and scientific research, Xie Youchang has done a lot of social work. He has served as the editorial board of university chemistry textbooks, the standing editorial board of Chemical Bulletin, the editorial boards of China chinese journal of catalysis, Molecular Catalysis, acta petrolei sinica, Journal of Fuel Chemistry and Natural Gas Chemical Engineering, and the member and deputy director of the Scientific Committee of the State Key Laboratory of Catalysis of Dalian Institute of Chemical Physics.
The most admired figure in his life is Zhuge Liang. I read Romance of the Three Kingdoms in primary school, and I was deeply impressed by stories such as Borrowing an Arrow from a Grass Boat, Huarong Road and Empty City Plan, which inspired him to make a surprise attack in scientific research in the future and use his wisdom in places that others can't easily think of. Zhuge Liang's motto "Be indifferent to your ambition, be quiet and far-reaching" has also become his motto. I am indifferent to fame and fortune in my work and life, strict with myself, lenient with others, and have a very harmonious relationship with colleagues and classmates. The good spirit of unity and cooperation has enabled his research group to achieve continuous results.
The experience of national disaster in his youth made Xie Youchang determined to contribute to the rejuvenation of China. In the early 1980s, he and his wife Yang went to the United States for further study. Their parents-in-law who have settled in the United States for a long time advised them to stay and work in the United States. They explained to their parents the needs of national construction and returned to China as scheduled. Later, he went abroad for patent technology transfer and cooperative research many times. A foreign company once asked him to stay at work and promised to arrange opportunities for his children to study abroad, but he also declined politely. He is determined to devote his whole life to the cause of science education in the motherland and do his best until he dies.