Fischer-Tropsch synthesis tubular fixed bed reactor with segmented cooling in catalytic bed layer

Abstract

The invention provides a Fischer-Tropsch synthesis tubular fixed bed reactor for segmented cooling in a catalytic bed layer, the reactor comprises an upper seal head, a cylinder and a lower seal head, the upper seal head is provided with a feed gas inlet; a reaction product outlet is formed in the bottom of the lower sealing head; continuous reaction tube nests are arranged in the barrel to be filled with a catalyst, the upper ends of the reaction tube nests are fixedly connected to the upper tube plate, and the lower ends of the reaction tube nests are connected with the lower tube plate; the barrel is divided into two or more cooling sections, each cooling section is provided with a cooling medium inlet and a cooling medium outlet, a partition tube plate is arranged between every two adjacent cooling sections, and the cooling medium temperature of the second cooling section is lower than that of the first cooling section. By optimizing the temperature of the cooling medium and the segmentation position, the heat exchange effect is improved, the Fischer-Tropsch synthesis reaction hot-spot temperature is reduced, uniform distribution of axial and radial temperatures of the bed layer is facilitated, temperature runaway of the bed layer is avoided, meanwhile, the pipe diameter of the reaction tube nest can be increased, the number of the reaction tubes can be reduced, and the reaction pressure drop can be reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical equipment, and in particular relates to a Fischer-Tropsch synthesis tubular fixed-bed reactor with segmental cooling in a catalytic bed. Background technique [0002] Coal and natural gas to liquid fuel is an important development direction of C1 chemical industry today, and Fischer-Tropsch synthesis is the most core part of the coal-to-liquid fuel process route. The Fischer-Tropsch synthesis reaction refers to the synthesis gas (CO+H) obtained from coal gasification or natural gas reforming. 2 ), the process of producing hydrocarbons and oxygenates directly from synthesis gas. The process was first proposed by German scientists Frans Fischer and Hans Tropsch in 1923, and the first industrial production took place in Germany in 1936. Fischer-Tropsch synthesis is a strong exothermic reaction, and the reaction temperature in the process has a crucial impact on the activity, stability and product ...

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Problems solved by technology

[0003] Industrial Fischer-Tropsch synthesis reactors mainly include fluidized bed, slurry bed and fixed bed reactors. The fluidized bed has good heat transfer performance and large production capacity, but the operation is complicated, the process is difficult to control, and the loss of catalyst is also very high. Large; the advantage of the slurry bed is that the reaction is well mixed and the heat exchange efficiency of the reactor is high, but the disadvantage is that the requirements for the catalyst are relatively high, and the separation of the liquid product and the catalyst is also a problem to be solved; the characteristic of the fixed bed reactor is that the form is flexible and diverse , simple operation, small back-mixing, low catalyst mechanical loss and simple structure, the disadvantages are that the bed heat transfer efficiency of the fixed bed reactor is low, there are hot spots in the reaction and the axial radial temperature difference is large, which affects the efficiency of the fixed bed reactor very restrictive

[0020] For the heat transfer process in a chemical reactor, the interaction between the chemical reaction and the heat transfer process in the reactor determines the steady-state interval of the reactor. The limiting effect of thermal measures, that is, a large Ua must be used t and a small temperature difference, otherwise the thermal temperature conditions cannot be met, which greatly limits the reaction conditions and scale of the fixed bed reactor

[0021] CN113426384 A provides a multi-stage fixed-bed reactor, a cooling water evaporation heat transfer chamber and a raw material gas heat transfer chamber are arranged between several reaction beds, which are separated by partitions, and the reaction can be controlled to a certain extent No fly temperature occurs, but it is difficult to precisely control the reaction temperature

Moreover, the structure and operation of the reactor are more complicated and the cost is higher

CN102211002 A discloses a fixed-bed reactor for Fischer-Tropsch synthesis, which is provided with a thermal oil circulation system, a light oil quenching system and a cold gas quenching system for regulating and controlling the temperature of the reaction bed, but due to There are many cycles in the system, the space-time yield of the target product is not ideal, and the circulation of hot oil and light oil increases the loss of the catalyst, and the separation of liquid products and catalysts is also a problem

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