Method and system for preparing propylene by oxidative dehydrogenation of chemical chain propane

Abstract

The invention relates to a method and system for preparing propylene through oxidative dehydrogenation of chemical chain propane. The method includes the following steps: propane reacts with oxygen carrier particles in a dehydrogenation reactor to generate propylene, water vapor and COx gas, and the oxygen carrier particles lose oxygen; separate propylene from the mixed gas; carry oxygen after oxygen loss The bulk particles undergo an oxidation reaction with the oxygen-containing gas to generate oxygen-poor gas and regenerated oxygen carrier particles. The regenerated oxygen carrier particles are circulated to participate in dehydrogenation. The system includes a dehydrogenation reactor, mixed gas purification equipment, mixed gas separation equipment, and an oxidation reactor. The dehydrogenation reactor can receive oxygen carrier particles generated in the oxidation reactor. The method and system for preparing propylene through oxidative dehydrogenation of chemical chain propane are highly efficient, energy-saving, environmentally friendly, economical and safe.

Description

technical field [0001] The invention relates to a method and system for preparing propylene by oxidative dehydrogenation of chemical chain propane. Background technique [0002] Propylene is an important basic raw material for chemical synthesis and plays an important role in the petrochemical industry. It is mainly used to synthesize other important chemical products such as polypropylene, acrylonitrile and acrylic acid. At present, 80% of the world's propylene comes from steam cracking or catalytic cracking (FCC) of naphtha and heavy crude oil, but these two processes mainly produce ethylene and refined oil, and propylene is only a by-product. form, so the production of propylene is severely limited. In recent years, with the rapid increase in the consumption of downstream derivatives of propylene, the demand for propylene has continued to rise, and the contradiction between supply and demand has become increasingly obvious. [0003] In order to increase the production o...

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Problems solved by technology

However, these emerging technologies also have some problems. As emerging coal chemical technologies, MTO and MTP need to experience coal / CH 4 -Synthesis gas-methanol-propylene multi-step process, resulting in a more complicated production process, lower product purity and higher equipment investment. In addition, if coal is used as raw material, it will consume a lot of water resources and emit a lot of CO 2 and NOx

DHP is a strong endothermic process, so the process needs to consume a lot of energy, and it needs to be carried out under high temperature and low pressure reaction conditions. Under such conditions, the catalyst is easily deactivated and needs to be regenerated repeatedly, and due to the limitation of thermodynamic equilibrium , the one-way propylene yield is not high (generally less than 30%)

ODHP is to feed oxygen and propane into the reactor at the same time in the presence of a catalyst to make propane react with oxygen to generate propylene and water. Although this technology can be carried out under milder conditions, it can also overcome the thermodynamics in the dehydrogenation process. Balance limit, but propane is prone to over-oxidation reaction in the presence of oxygen to generate COx gas (carbon monoxide and carbon dioxide), which will reduce the yield of propylene, and the use of oxygen will also increase the operating cost, which is not conducive to the safe operation of the equipment. In addition, the The technology also requires expensive air separation plants to ensure a constant supply of oxygen

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