Review of "Catalyst" Frontier Technology Research

1. Introduction

• The main function of catalysts is to reduce the activation energy of chemical reactions and speed up the reaction, so they are widely used in refining, chemical, pharmaceutical, environmental protection and other industries. The technological progress of catalysts is one of the most effective driving forces to promote the development of these industries. The advent of a new type of catalytic material or a new catalytic process often triggers revolutionary industrial changes, accompanied by huge social and economic benefits.

• In 1913, the advent of iron-based catalysts enabled the synthesis of ammonia, and the fertilizer industry has since developed rapidly worldwide; in the late 1950s, Ziegler-Natta catalysts pioneered the synthetic materials industry; in the early 1950s, molecular sieves triggered a revolution in the field of catalysis with their special structure and properties; in the 1970s, automobile exhaust purification catalysts were industrialized in the United States and attracted widespread attention worldwide; in the 1980s, metallocene catalysts enabled new development opportunities for the polyolefin industry. At present, human beings are facing many major challenges, such as: the dwindling of resources, the need for rational development and comprehensive utilization of resources, and the establishment and development of resource-saving agricultural, industrial, transportation and living systems; economic development has caused environmental pollution to spread and natural ecology to deteriorate, requiring the establishment and development of ecological industries with full recycling of substances, and the realization of cleanliness from production to application. The solution to these major problems is closely related to catalysts and catalytic technologies. Therefore, many countries, especially developed countries, attach great importance to the development of new catalysts and catalytic technologies, and regard catalyst technology as a priority for development in the new century.

2. The development trend of foreign catalyst technology

• After long-term development, the application field of catalysts has tended to the following situation: traditional petrochemical technology is basically mature, but new catalysts are needed to meet the deterioration of raw material properties, product upgrading and increasingly harsh environmental protection requirements; natural gas chemical and coal chemical industry cannot compete with petrochemical industry economically, and the catalytic technology involved is very similar; fine chemical catalytic technology for the synthesis of high value-added chemicals and pharmaceutical intermediates is relatively scattered, the development is slow, and it is currently being strengthened; Catalytic technology for the purpose of environmental governance and environmental protection has received extensive attention.

•  According to statistics, the output value of petroleum processing in the world is more than 94 billion US dollars, and the basic organic chemical industry and the fine chemical industry are about 520 and 48 billion US dollars respectively. Although the sum of the latter two is lower than the former in terms of output, its output value has exceeded that of petroleum processing, and it is on the rise. Innovation in new catalysts, high-efficiency catalytic reaction technologies, new catalytic materials and common technologies for catalyst preparation is the core to promote the development of these industries. Among them, the development of environmental protection catalytic processes and corresponding new catalysts, catalyst preparation refinement, etc. is the key, and it is also the main development direction of catalyst technology in the future.

2.1 The development and application of new catalysts have developed rapidly

2.1.1 refining and chemical catalysts

• The development of new and efficient catalysts is the basis for the leap-forward development of the petroleum and chemical industries. In recent years, nearly 50% of the international research on catalysis has been focused on the development of new catalysts, and the importance of them is increasing. Another significant feature is that the development of new catalysts is closely related to environmental friendliness, that is, catalysts and catalytic technologies are required to produce essential products while eliminating pollution from the source. Judging from the number of research papers included in the international authoritative search system, reports on new catalysts have increased by at least 15 times from 1990 to 1999. Among them, new catalysts such as solid acids, solid bases, and selective oxidation have developed extremely rapidly. Solid acid catalysts are a new type of catalysts developed internationally in recent years. They can replace traditional sulfuric acid catalysts in important reactions such as esterification, alkylation, and isomerization, and eliminate pollution from the source, thus becoming the most powerful new type of catalysts.

• Homogeneous alkali catalysis occupies a considerable proportion in the synthesis of chemicals, such as the synthesis of surfactants by ring-opening addition of epoxides, the preparation of fine chemicals by transesterification, etc., but it has a severe impact on the environment due to serious pollution problems. In recent years, it has become an inevitable development trend to replace traditional liquid alkali catalysts such as sodium hydroxide with solid bases.

• Due to the requirements for catalyst activity, economy, and environmental protection, the research focus of coal liquefaction catalysts has been focused on the preparation and addition of ultrafine-grained dispersed iron-based catalysts. Future research topics still need to be introduced by ion exchange method. The improvement of direct impregnation methods, the application of nano-scale iron oxides and modified (vulcanized) iron oxides, and the addition of low-concentration metals that can promote the improvement of iron-based catalyst activity.

2.1.2 vehicle exhaust purification catalyst

• With the application of new automotive engine technologies and increasingly stringent environmental regulations, automotive exhaust gas conversion catalysts will show the following development trends. First, in order to improve fuel combustion efficiency and reduce CO emissions, automotive engines will gradually adopt lean combustion technology. According to relevant reports, the engine's fuel economy is 20% to 25% higher than that of conventional engines. Due to excess oxygen, NOX reduction removal has become a technical problem. Solutions currently being studied include NOX capture, selective reduction, and electrothermal catalysts, which are expected to be industrialized in Europe in the near future. The second is to design catalysts that can quickly warm up when the engine is cold started.

• In Europe and North America, vehicle emissions are mainly caused by early emissions before the catalytic converter is preheated. In the next few years, stricter emission restrictions that will come into effect in the United States, Europe, and Japan are mainly aimed at the purification of exhaust gases 20-30s before start-up. In addition, manufacturers of automotive exhaust conversion catalysts are working to reduce the amount of precious metals in the catalyst. The third is to eliminate H2S emissions. Vehicles newly fitted with catalytic converters produce unpleasant odors when they are driven. This is due to the accumulation of sulfur in the catalytic converter being discharged in the form of H2S, and suitable solutions are currently being studied.

2.1.3 photocatalyst

• The oil crisis in the early 1970s not only brought about the rapid development of photoelectrochemistry, but also attracted extensive attention to the field of photocatalysts. In the past 30 years, photocatalysis and related technologies have been rapidly developed due to potential applications in environmental treatment, solar energy conversion, clinical medicine, etc., especially in wastewater treatment and solar energy conversion.

• From the perspective of the prospect of photocatalyst application, the current main application fields: First, the self-cleaning function of titanium dioxide coatings. Titanium dioxide is plated on the surface of building materials, vehicles, and interior decoration materials, and the use of sunlight and lighting in life can decompose these surface pollutants. Rainwater cleaning realizes self-cleaning function. Second, superhydrophilic energy is used to prepare anti-fog equipment. For example, glass coated with superhydrophilic photocatalytic film forms a uniform water film on the surface when it encounters water vapor, so the mirror image remains clear. Third, the purification of air and water resources. There are various different fields of water treatment, such as the treatment of upper and lower water sources, factory drainage, and agricultural drainage. In medicine, it is used to eliminate germs and viruses. In addition, photocatalytic reactions also have potential applications in corrosion protection, printing, optical storage, and many other fields.

2.1.4 biocatalyst

• Biocatalyst technology is an integral part of chemical biotechnology, and its importance as a means or tool for chemical synthesis is increasing. Consumer demand for new products, industry demands to increase profits and reduce costs, pressure from government and administrative departments to strengthen management, and the emergence of new technologies and scientific inventions have promoted the application of biocatalysts.

• The new biocatalysis process developed by BASF is mainly for the production of high-value-added products rather than general-purpose chemicals, including amino acids such as lysine and methionine, octane hydroxylation to produce octanols, and vitamins, which has not yet had an impact on general-purpose chemical businesses such as polypropylene or polystyrene.

• There have been many breakthroughs in the field of biocatalysis. In the manufacturing of biomedicine, DSM has developed biocatalysis for the production of the antimicrobial intermediate-7 aminoacetic acid-based benzyl cephalosporinic acid (7ADCA). Several chemical companies are developing new biocatalytic pathways for the manufacture of industrial chemicals. DuPont's joint venture with Tate & Lyle Citric Acid develops a biological pathway for the production of 1,3-propanediol (PDO): DuPont's raw material for polytrimethylene terephthalate (PTT) plastics. The joint venture has engineered fermented microorganisms to produce PDO from grain sugars. DuPont's current PTT market for the production of PDO through chemical synthesis is expected to be replaced by a biological PDO unit in 2003. There are currently millions of teams conducting biocatalysis research worldwide, and in the next decade, many R & D institutions are expected to successfully develop new biocatalytic processes for use in the chemical industry. Biocatalysts are showing a high growth rate in the fine chemicals market.

3. Recent status of foreign diesel hydrotreating catalysts

3.1 Akzo-Nobel STARS and NEBULA catalyst technologies

• The Dutch company Akzo-Nobel and the Japanese company Ketjen have launched two STAS catalysts: KF 757 and KF 848, which have now achieved industrial application. KF 848 is a NiMo catalyst applied at higher pressure, and KF 757 is a CoMo catalyst applied at low to medium pressure. The HDS and HDN activity and stability of the STARS catalyst are 50-60% higher than those of the previous generation. KF 757 is used for ultra-deep desulfurization of distillate oil, and the sulfur content of the product diesel can reach 50 μg/g. The raw material can be straight-run diesel or catalytic diesel, with a sulfur content of 0.8-2.0% and a hydrogen partial pressure of 1.5-6.5 MPa.

3.2 Catalysts developed by Japan Catalyst Chemical Corporation and Japan Institute of Materials and Chemistry

• This catalyst is composed of platinum, palladium, ytterbium and other metals supported on a molecular sieve support. It can be operated under similar conditions to conventional nickel-based catalysts, under the conditions of: about 300 ° C and 5MPa. The sulfur content of diesel can be reduced to 10~ 20 μg/g. The cost of this catalyst is several times more expensive than that of nickel-based catalysts, but it has a longer service life. Orient Catalyst Company of Japan has also developed a bi-catalyst system for desulfurization of diesel oil, which can reduce the sulfur content of diesel oil to below 50 μg/g. One is a CoMo catalyst supported by alumina, which handles organic sulfides such as alkyl sulfides, mercaptan and alkyl polysulfides. The other is a NiMo catalyst supported by alumina, which can decompose and remove sulfur in polycyclic compounds such as alkyl dibenzothiophene. It can be operated under conventional reaction conditions (340-370 ° C and 5-7 MPa).

3.3 New catalysts for hydrotreating developed by Axens

• Axens has developed a new series of hydrotreating catalysts: HR400. These catalysts have high activity and maintain good stability in the production of ultra-low sulfur diesel fuel (ULSD). HR406 is a cobalt-molybdenum (CoMo) catalyst, which is especially suitable for mitigating operating conditions, such as naphtha or kerosene desulfurization. For very light to light feedstocks, there is high desulfurization activity. HR426 is an adjuvant-containing CoMo catalyst for the production of ULSD. It is suitable for straight distillation gas oil (SRGO) or mixtures of SRGO with certain pyrolysis fractions, which can make the sulfur content less than 10 μg/g. The catalyst also desulfurizes alkyl dibenzothiophene. Suitable for low or medium pressure devices with long residence times. Minimizes hydrogen consumption. HR448 is an adjuvant-containing NiMo catalyst with high hydrogenation activity and high desulfurization rate. Can handle difficult-to-process feeds at high pressure. Feeds can be heavy feeds with high nitrogen content or high pyrolyte content. This catalyst system combines high desulfurization and denitrification activity. HR468 can replace HR426 CoMo or HR448 NiMo catalysts. Can be used for deep or ultra-deep desulfurization of diesel. High hydrogenation activity makes it flexible to handle difficult-to-process feeds, and can also be used for low-pressure units to pretreat FCC feeds.

4. Introduction to other unit hydrogenation catalysts at home and abroad

• AlbemarleSupply various hydrotreating catalysts required by the market. In the United States, while the demand for automotive diesel is growing, the reduction of sulfur content in non-automotive diesel and marine fuel oil are two bright spots for future catalyst market demand growth. Nebula catalysts are designed to produce ultra-low sulfur diesel. Recently, Albemarle acquired Akzo's catalyst business, claiming that the catalyst business is expected to be further developed as refineries produce high-quality transportation fuels.

• CriterionIt is the world leader in hydrotreating catalysts for the refining industry. The company's research and development work focuses on the production of better ultra-low sulfur diesel hydrotreating catalysts, improved hydrocracking catalysts, and the production of better new residue hydrotreating catalysts. Because many cracked naphtha needs to be reformed, it also does some research and development work on naphtha hydrotreating catalysts. Coking naphtha and synthetic crude oil naphtha contain more arsenic and silicon.

• UOP CorporationThe company's work focuses on conventional catalysts and has also developed catalysts for the production of biodiesel, which produces fatty acid methyl esters (FAME), and green diesel, which produces synthetic or green diesel by hydrotreating various vegetable oils with petroleum distillates.