RU1810342C - Method of process stabilization of ethylene oxide synthesis - Google Patents

Abstract

Usage: in the production of glycols, glycol ethers. SUMMARY OF THE INVENTION: ethylene oxide. Reagent 1: ethylene. Reagent 2; oxygen. Conditions for carrying out: transfer to a stabilizing plant is carried out according to the instability of the reactor — the presence of propylene at the outlet of the reactor at a concentration of 0.10-0.30 ppm.

Description

The invention relates to olefin oxides, in particular to a method for stabilizing the production of ethylene oxide by oxidizing ethylene on a silver tribrach catalyst. Ethylene oxide is used for the production of glycols, glycol ethers and nonionic surfactants, which are widely used in the chemical industry.

The aim of the invention is to increase the average reactor productivity and ethylene oxide quality.

The goal is achieved by stabilizing the process of producing ethylene oxide by selective oxidation of ethylene with oxygen or an oxygen-containing gas in the presence of a silver tribrach catalyst, and the transfer to the stabilizing mode is carried out according to the instability of the reactor — the presence of propylene at the outlet of the reactor at a concentration of from 0.1 to 0.3 ppm. Propylene in the feed gas, due to its high reactivity, compared with methane, is rapidly oxidized and the output concentration of propylene only indicates undesirable processes in the reaction tubes. It is necessary to make a balance on propylene NBT, but it is enough to know its concentration at the outlet of the reactor.

The appearance of propylene at the outlet of the reactor allows one to reliably detect, at an early stage, the beginning instability of the reaction and appropriate methods, for example, by slowing down the reaction for a certain time or by briefly stopping the reactor, to eliminate it at an early stage.

During the synthesis, the concentration of propylene is continuously monitored. By increasing the concentration of propylene to 0V1-Q, 3 ppm, the ethylene and oxygen load decreases for a short time, and the reaction system spontaneously stabilizes, after which the reactor is brought to full load. Due to the speed and satisfactory accuracy of the analysis for a given concentration of propylene, an increase in reactor productivity is achieved.

Example 1. The installation for the production of ethylene oxide worked at full load under the following conditions under the following conditions:

00

about

with

4V

go

214 ° C

Oxygen inlet concentration 6.7%,%. Ethylene. 19 vol.% Gas inlet temperature

Heat carrier 249 ° О Total pressure 2MPa Ethylene load 5600 kg / h Ethylene oxide yield under these conditions was 1.32 vol.%, Which corresponded to the design capacity. Analysis for propylene at the outlet of the reactor was carried out every 10 min and showed no propylene 8 for several months at full load. At the same time, in accordance with the known method, a methane balance was applied, which had a negative value and ranged from - (0.26-0.32) nm3. Then at the exit from the reactor in trace amounts, the pitchfork is propylene. After another 2 hours, the propylene concentration reached 0.10 ppm. The methane balance remained negative and was 0.25 nm. The concentration of aldehydes at the outlet of the reactor increased by 1.5 times. The unit was switched over to a load reduced in ethylene to 5350 kg / h with a decrease in oxygen concentration by 0.3 vol. % The yield of ethylene oxide under these conditions became 1.26 vol%. In this state, the reactor worked for 44 hours and no propylene was detected at the outlet. It was not detected. After that, for the next 3 hours, the reactor was brought to full load and operated for a long time. The ethylene load and ethylene oxide concentration decreased by 4.5%. Thus, the productivity was reduced only by 4.5% over a period of 44 hours. The concentration of aldehydes at the outlet of the reactor approached the nominal value.

PRI me R 2. After working for a long time, at full load under the conditions shown in example 1 ,. at the exit of the reactor, the vils are propylene in trace amounts. After 4 hours, the propylene concentration increased to 0.22.ppm, the aldehyde concentration increased 1.6-1.8 times the nominal value, the methane balance remained negative and was -0.22 nm3. The reactor was transferred to a reduced ethylene load from 5700 kg / h to 3700 kg / h at an oxygen concentration of 4 vol.%. The temperature of the coolant at the inlet was reduced by 4 ° C. After that, the reactor was operating at a reduced load of 14 hours, and after 4 hours of operation, propylene was not detected in the output. The concentration of ethylene oxide during the unloading period decreased to 0.79-0.83 vol.%. Then, over the next 18 hours, the reactor was brought to full load. The average productivity of the reactor dropped by 40% within 14 hours. The concentration of aldehydes at the outlet approached the nominal value.

PRMmerZ. After working for a long time at full load under the conditions specified in example 1, at the exit of

reactor for vils propylene in trace

quantity. After 2.5 hours, the propylene concentration increased to 0.3 ppm. The concentration of aldehydes at the outlet of the reactor increased 1.7-2 times from the nominal

values, and the methane balance was negative and was -0.18 nm. The reactor was transferred to a reduced load from 570Q kg / h to 3700 kg / h of ethylene with an oxygen concentration of 4 vol.%. The temperature of the coolant at the outlet was reduced by 4 ° C. The reactor was then operated for 20 hours under reduced load, and after 5 hours of operation no propylene was detected at the outlet. The concentration of ethylene oxide decreased to 0.780, 82 vol.%. Then, over the next 18 hours, the reactor was brought to full load and worked for a long time. Thus, the reactor productivity for only 20 hours was 40% lower.

nominal value. The concentration of aldehydes at the outlet of the reactor approached the nominal value,

For example (for comparison). After work for a long time at full ..

the load at the outlet of the reactor in trace amounts on the forks is propylene. 3 hours after this, the concentration of prs, n, and silt reached 0.35 ppm, and the methane balance was negative and amounted to -0.16 nm.

this did not take the measures indicated; in examples 1-3. The reactor continued to operate at full load, the concentration of propylene ranged from 0.3-0.55 ppm. 46.4 after the appearance of traces of propylene. an explosive phenomenon occurred in the reactor, while only 42 hours after the appearance of propylene the methane balance took a positive value of +0.04 nm. An explosive phenomenon

led to rupture of the membrane and damage to the mixing unit. The reactor was shut down abnormally. Repair work was carried out and at full load the reactor was withdrawn after 18 days from the moment of shutdown "and, .. /

Thus, the proposed method allows to increase the average productivity of the processes to improve the quality of the target product.

51810342 b

The formula of the invention is that with the aim of increasing

average productivity of the reactor and a method for stabilizing the process of ethylene oxide pollen, selective stabilization of ethylene oxide is carried out according to the oxidation of ethylene with oxygen or kis-5, which indicates the instability of the work with a reactor-containing gas in the presence of sulfur — the presence of propylene at the exit from a reactive tribrach catalyst, about 1 liter at a concentration of 0.10-0.30 ppm.