CS232175B1 - to reduce the build up of deposits in the preheaters of the vinyl acetate synthesis mixture - Google Patents

Abstract

The invention relates to increasing the productivity of the equipment for the production of vinyl acetate and solves the method of reducing the formation of deposits in the preheaters of the synthetic mixture of the production of vinyl acetate from acetylene and acetic acid by the vapor phase method. The essence of the present invention consists in draining off part of the acetic acid injected into the evaporators, by means of which the high-boiling substances formed are continuously removed and their possible penetration by abduction of drops into the preheaters of the synthesis mixture is prevented. The penetration of droplets as the cause of the formation of an increased amount of deposits is prevented by the regulation of the level of liquid acid in the evaporators, which is kept below the level of the upper face of the tube sheet. The method according to the invention prevents the accumulation of high-boiling substances in acetic acid in the evaporators and a significant increase in the usable pool of production equipment is achieved.

Description

232 175

BACKGROUND OF THE INVENTION The present invention relates to a method for reducing the formation of deposits in the pre-heaters of a synthetic mixture of the production of vinyl acetate in acetylene and ootic acid by a phasic process.

The heating of the synthesis mixture consisting of an ethylene and ootic acid vapor in the vapor phase process for the production of vinyl acetate used tubular heat exchangers »The source of heat is the high pressure steam conducted to the inter-tube space. The synthesis of the mixture is next to the tubes in the tubes * Over time, there is a build-up of solid deposits and, therefore, the device needs to be cleaned. The intensity of the formation is rude and depends on the concentration and the nature of the non-purifying material in the raw materials. blends and from the purity of recycled ootic acid * We know, Acetylene recovered from calcium carbide contains a smaller number of contaminants and, in a lower concentration, produced by the cleavage of natural gas * Following the formation of tungsten carbide coating technologies. Significantly Lower * Sometimes such an extent that frequent preheating of the heaters significantly reduces the performance of the production equipment of the natural gas-based ethylene * Pre-heater cleaning is a time-consuming operation;

The above drawbacks are overcome by the method of reducing the formation of molds in the preheaters of the same mixture of vinyl acetate and acetic acid production by a parasic process at temperatures ranging from 150 to 200 ° C, wherein 0.001 to 0 is removed from the bottom of the acetic acid evaporator. 1 part by weight of the total hourly amount of acid feed into the evaporator. The liquid acid level in the evaporator 232 175 measured in the droplet separator is maintained at the top level of the heat exchanger tube sheet and the acidic portion removed by the methods # The principle of the present invention is based on the monitoring and analysis of the deposit formation process. Non-impurities are present in the non-impurities present. Further, it has been found that tietools are dissolved in acetic acid under the conditions of evaporators # The most important finding is the fact that it only finds the abduction of droplets that contain impermeable substances from evaporators to preheaters # By controlling the level of ootic acid in the evaporators at optimum temperature, the penetration of kva-peaks into the vapor to the preheaters is prevented # The non-volatile substances that are objectively formed in the evaporation process remain dissolved ootovej acid and was added as a solution by continuous preruáovane them or discharged from the bottom into the container odperovačov # of acetic acid from the container to be regenerated spraouje KYSE-proline methyl ester of acetic known ep6sobini #

The advantage of the present invention lies in the simplicity of its implementation, with the use of existing manufacturing equipment with a fine adjustment of the pipeline connection. pre-heaters, to reduce the laboriousness of cleaning equipment, and thus to increase the use of the Sp6-eob Working Time Fund of the present invention has been successfully verified on a manufacturing facility, as shown in the following example # Example 1

On the lower part of the pipe connecting the bottom of the evaporator separator, a drain line provided with a valve and a visor to visually inspect the flow was connected. In the course of the synthesis cycle, the acidoot was withdrawn by this line in a quantity of 50 to 70 kg / hect. one vaporizer #

Claims (1)

A mixture of the production of vinyl acetate from acetyl and ootic acid by a parophasic process at temperatures of 150 to 220 ° C, characterized in that 0.001 to 0.1 part by weight of the total hourly amount of acid metered into the evaporator is continuously or intermittently withdrawn from the bottom of the ootic acid evaporator. of the acid in the evaporator measured in the droplet separator is maintained at the highest level of the upper face of the heat exchanger tube sheet and the removed part of the acid is sprayed by known methods *