RU200509U1 - Apparatus for conducting reactions in a suspended bed in a gas-liquid-solid system - Google Patents

Abstract

The utility model relates to an apparatus for carrying out reactions in a suspended bed in a gas-liquid-solid system. A utility model is proposed, which is an apparatus for carrying out reactions in a suspended bed in a gas-liquid-solid system, including pipelines for inlet and outlet from the top of the gas-liquid flow, hatches for input from above and output from the bottom of the solid, a distributor of the initial gas-liquid flow located in the lower part of the apparatus and having caps installed along the entire section of the apparatus with slots upward, and a collector of the reaction gas-liquid flow located in the upper part of the apparatus and having caps , installed with slots downward or at an angle to the vertical from 1 ° to 90 °, while the width of the slots on the distributor and the gas-liquid flow collector is less than the smallest particles of solid matter. -liquid-solid this substance and use it for the esterification of carboxylic acids with aliphatic alcohols in the presence of cation exchangers.

Description

The utility model relates to an apparatus for carrying out reactions in a suspended bed in a gas-liquid-solid system.

When carrying out reactions between gas and liquid in the presence of a solid catalyst, a three-phase system arises. The chemical interaction of the components occurs on the catalyst surface. In the presence of a liquid phase, solid catalyst particles are immersed in it. The reaction components from the gas phase, before reaching the catalyst surface, must dissolve in the liquid. The gas in the reactor is usually fed from the bottom of it. In this case, it is advisable to feed the liquid together with the gas. Under certain conditions, depending on the gas velocity, liquid density, density and fractional composition of the catalyst, a three-phase suspended layer is formed.

For uniform distribution of gas over the cross section of the apparatus, various designs of distributors are used. Most often this is a system of pipes located in the lower part of the apparatus near the bottom, in which holes are made. Sometimes porous plates are used for this.

This is how a gas distributor for a reactor is known (RF Patent 2365407, 2009), which is a system of pipes located near the bottom of the reactor with holes directed downward. The disadvantage of this invention is the absence in the reactor for which the distributor is intended, the possibility of draining the liquid phase and preventing the carryover of the catalyst through the top of the reactor.

Known suspension apparatus (RF Patent 2566406, 2015), in which gaseous components are fed into the suspension through a gas distributor, which has downward gas outlets, and the apparatus below the gas inlet is closed over the entire section by a liquid-impermeable partition. The disadvantage of the apparatus is the lack of the possibility of input and output of the liquid phase.

A reactor for carrying out chemical reactions in a three-phase system is known (RF Patent 2153928, 2000). It is supplied with gas and liquid together with a catalyst; there are devices for distributing gas and a mixture of liquid and solid phases. The gas from the reactor is removed separately, and the liquid and catalyst are removed together. The disadvantage of this reactor is the impossibility of removing the liquid from it while maintaining the catalyst in it.

The closest to the claimed utility model is a catalytic solid-liquid multiphase reactor (RF Patent 2120820, 1998). The device is equipped with a gas distributor in the form of a plate or a porous plate. The inlet of the suspension is carried out in the upper part of the reactor under the bubbling layer and its outlet - from the bottom above the gas distributor. The liquid phase is removed from the reactor using a filter element, which is a filter mesh with mesh sizes less than half the minimum catalyst particle size. The filter element contains a constant level device that provides a pressure difference between the suspension zone and the filtered liquid. If this differential increases, the filter element may become clogged. The anti-clogging effect can occur due to the passage of gas bubbles through the filter mesh together with the liquid.

This design of the device has a number of disadvantages:

- the filtering element occupies a part of the section of the apparatus, due to which the useful volume of the apparatus is reduced;

- with a change in the flow rates of gas and liquid in the reactor, the pressure drop between the suspension and the filter element will change, as a result of which the catalyst can clog the filter mesh;

- bubbles passing in the area of the filtering mesh will not penetrate through it, since their movement is directed upwards, and the movement through the filtering mesh occurs at an angle of -90 ° to the vertical. So due to this movement, the mesh will not be cleared.

The objective of this utility model is to develop a fairly simple apparatus for carrying out the process in a three-phase gas-liquid-solid system and its use for the esterification of carboxylic acids with aliphatic alcohols in the presence of cation exchangers.

The problem is solved by the proposed utility model, which is an apparatus for carrying out reactions in a suspended bed in a gas-liquid-solid system, including pipelines for inlet from below and outlet from above of a gas-liquid flow, hatches for inlet from above and outlet from below of a solid, a distributor of an initial gas-liquid flow located in the lower part of the apparatus and having caps installed along the entire section of the apparatus with slots upward, and a collector of the reaction gas-liquid flow located in the upper part of the apparatus and having caps installed with slots downward or at an angle to the vertical of 90 °, while the width of the slots is the distributor and manifold of the gas-liquid flow is smaller than the smallest particles of the solid.

Unlike the prototype, where a suspension of liquid and solid matter enters the apparatus into the upper part of the apparatus, and a suspended layer of gas-liquid-solid substance is achieved by supplying a gas component from the bottom of the apparatus, in the inventive apparatus the solid substance is placed into the apparatus beforehand, and the gas-liquid flow is directed from below apparatus, creating a suspended layer in the gas-liquid-solid system.

The design of the apparatus is shown in figure 1, which shows the flows and elements of the inventive apparatus:

I. Initial gas-liquid stream;

II. Outgoing gas-liquid reaction stream.

1. A pipeline for the input of the initial gas-liquid flow;

2. Bottom caps on the distributor of the initial gas-liquid flow;

3. Top caps on the reaction gas-liquid flow manifold;

4. Collector;

5. Pipeline for the output of the gas-liquid reaction flow;

6. Top hatch;

7. Bottom hatch.

The required amount of solid is pre-loaded into the apparatus. The solid substance is charged through the top hatch 6 past the collector 4 and the upper caps 3. The solid substance can also be loaded into the apparatus with the top cover removed and the collector 4 removed.

The initial gas-liquid flow I is fed into the apparatus through the pipeline 1 and is distributed over its cross-section using the lower caps 2 located along the entire cross-section of the apparatus with slots upward on the gas-liquid flow distributor. Rising along the height of the apparatus, the flow, being in a suspended layer in the gas-liquid-solid system, reacts and passes the upper caps 3, installed with slots downward or at an angle to the vertical 90 °, is collected in the manifold 4, while the width of the slots on the distributor and the collector of the gas-liquid flow is smaller than the smallest solid particles. The gas-liquid stream leaves the apparatus (stream II) through the pipeline 5. The discharge of the spent solids occurs through the lower hatch 7 as required.

The use of the proposed apparatus was carried out in the preparation of esters of carboxylic acids by esterification of carboxylic acids with aliphatic alcohols in the presence of cation exchangers, for example, by esterification of acetic acid with ethanol in the presence of a cation exchanger in the form of grains.

After loading the cation exchanger into the apparatus through the upper hatch 6, activating it with sulfuric acid and rinsing it with demineralized water to pH = 3-4, the cation exchanger is poured with acetic acid. The apparatus is heated to a temperature of ~ 100 ° C, and an equimolar mixture of acetic acid and ethanol (stream I) is fed into it through the pipeline 1 under the layer of cation exchanger, using the lower caps 2 located along the entire section of the apparatus with slots upwards, on the distributor of the gas-liquid flow. Rising along the height of the apparatus, the gas-liquid flow, passing through the catalyst bed of the cation exchanger in the form of grains and being in the suspended bed in the gas-liquid-solid system, reacts and passes the upper caps 3, installed with slots downward or at an angle to the vertical 90 °, collecting in the manifold 4, while the width of the slots on the distributor and the manifold of the gas-liquid flow is less than the smallest particles of solid matter. The stream leaves the apparatus (stream II) through the pipeline 5.

Unloading of the spent cation exchanger occurs as needed through the lower hatch 7.

For the process of producing esters by the method of ethanol esterification of acetic acid in the presence of a cation resin catalyst, the minimum particle size is in the range of 0.25-1.5 mm. Thus, the size of the slots on the distributor of the initial gas-liquid flow and on the collector of the reaction gas-liquid flow should be no more than 0.2 mm. In the experiments, an apparatus was used, in the collector of which, in its upper part, caps with slots directed downward and at an angle of 90 ° were located.

Table 1 shows examples of obtaining an ester of acetic acid (ethyl acetate) by the method of esterification of acetic acid with ethanol in a three-phase system in the presence of cation exchangers using the proposed apparatus.

From table 1 it can be seen that the conversion of alcohol per pass is 65-90%, which depends on the load on the cation exchanger. The ether selectivity is in the range 99.6-99.85%. This means that very few by-products are generated in the process.

Thus, a fairly simple apparatus has been developed that allows the process to be carried out in a three-phase gas-liquid-solid system and to use it for the esterification of carboxylic acids with aliphatic alcohols in the presence of cation exchangers.

Claims (1)

Apparatus for carrying out reactions in a suspended bed in a gas-liquid-solid system, including pipelines for inlet from below and outlet from above of a gas-liquid flow, hatches for inlet from above and outlet of a solid substance from the bottom, a distributor of the initial gas-liquid flow located in the lower part of the apparatus and having caps installed along the entire section of the apparatus with slots upward, and the collector of the reaction gas-liquid flow, located in the upper part of the apparatus and having caps installed with slots downward or at an angle to the vertical of 90 °, while the width of the slots in the caps on the distributor and the gas-liquid flow collector is less than the smallest particles of solid.

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