Classification method for industrial catalysts in China
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I. Petroleum refining catalysts 1. Catalytic cracking catalysts 2. Catalytic reforming catalysts 3. Hydrocracking catalysts 4. Hydrofinishing catalysts 5. Alkylation catalysts 6. Isomerization catalysts II. Inorganic catalysts 1. Desulfurization – hydrodesulfurization, sulfur recovery catalysts 2. Conversion – natural gas conversion, refinery gas conversion, light oil conversion catalysts 3. Shift reaction – high (medium) shift, low shift, sulfur-tolerant wide shift catalysts 4. Methanation – syngas methanation, city gas methanation 5. Ammonia synthesis catalysts 6. Ammonia decomposition catalysts 7. Primary and secondary hydrogen conversion catalysts 8. Sulfuric acid production catalysts 9. Nitric acid production catalysts 10. Sulfur recovery catalysts III. Organic chemical industry catalysts 1. Hydrogenation catalysts 2. Dehydrogenation catalysts 3. Oxidation – gas-phase, liquid-phase catalysts 4. Ammonia oxidation catalysts 5. Oxychlorination catalysts 6. CO+H2 synthesis – synthetic alcohol, F-T synthesis catalysts 7. Acid-catalyzed reactions – hydration, dehydration, alkylation catalysts 8. Olefin reactions – oligomerization, polymerization, disproportionation, addition catalysts IV. Environmental protection catalysts 1. Nitric acid exhaust treatment catalysts 2. Internal combustion engine exhaust treatment catalysts 3. Nitrogen production catalysts 4. Purification – catalysts for removing trace amounts of oxygen or hydrogen V. Other catalysts Other catalysts
There are three types of catalysts: homogeneous catalysts, heterogeneous catalysts, and biocatalysts. Homogeneous catalysts and the reactants they catalyze are in the same state of matter (solid, liquid, or gas). For example: if the reactants are gases, then the catalyst will also be a gas. Nitrous oxide is an inert gas that is used as a **anesthetic**. However, when it reacts with chlorine and sunlight, it decomposes into nitrogen and oxygen. At this point, chlorine acts as a homogeneous catalyst, breaking down the otherwise stable nitrous oxide into its constituent elements. Heterogeneous catalysts and their reactants are in different states. For example, in the production of margarine, unsaturated vegetable oils and hydrogen can be converted into saturated fats using solid nickel as a catalyst. Solid nickel is a multiphase catalyst, and the reactants it catalyzes are liquid (vegetable oil) and gaseous (hydrogen). Enzymes are biological catalysts. Living organisms use them to accelerate chemical reactions within their bodies. Without enzymes, many chemical reactions in living organisms would proceed very slowly, making it difficult to sustain life. At a temperature of around 37°C (the body’s temperature), enzymes operate at their optimal level. If the temperature is above 50°C or 60°C, the enzyme is destroyed and can no longer function. Therefore, biological detergents that use enzymes to break down stains on clothes are most effective when used at low temperatures.