Method for producing ethylene oxide

Patent metadata

Field	Value
Publication number	US-10858328-B2
Application number	US-201716088748-A
Country	US
Kind code	B2
Filing date	Mar 30, 2017
Priority date	Mar 30, 2016
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

According to the present invention, there is provided means for suppressing the occurrence of corrosion on the inner tube side in a heat exchanger and enabling continuous production for a long time period in a process for producing ethylene oxide.
An embodiment of the present invention relates to a method for producing ethylene oxide, the method including: supplying a raw material gas including ethylene, molecular oxygen, and a chlorine compound to an ethylene oxidation reactor; subjecting ethylene and molecular oxygen in the raw material gas to catalytic vapor phase oxidation in the ethylene oxidation reactor in the presence of a silver catalyst, and thereby producing a gas including ethylene oxide, water, and a chlorine compound; and cooling a gas to be cooled including water and the chlorine compound using a heat exchanger. According to this method, in the heat exchanger, the gas to be cooled including water to be cooled and a chlorine compound is cooled at a linear gas velocity on the heat exchanger inner tube side of 7 m/s or higher.

First claim

The invention claimed is:

1. A method for producing ethylene oxide, the method comprising:
supplying a raw material gas comprising ethylene, molecular oxygen, and a chlorine compound to an ethylene oxidation reactor;
subjecting the ethylene and the molecular oxygen in the raw material gas to catalytic vapor phase oxidation in the ethylene oxidation reactor in the presence of a silver catalyst, and thereby producing a gas comprising ethylene oxide, water, and a chlorine compound; and
cooling a gas to be cooled comprising the water and the chlorine compound using a heat exchanger,
wherein in the heat exchanger, the gas to be cooled is cooled at a linear gas velocity on the heat exchanger inner tube side of 7 m/s or higher,
wherein the heat exchanger inner tubes are made of stainless steel, and the contents (mass %) of chromium (Cr) and molybdenum (Mo) with respect to the total mass of the stainless steel satisfy the relation of the following Formula 1:
11≤Content of chromium (mass %)+2×content of molybdenum (mass %)≤18.

2. The production method according to claim 1 , wherein
in the heat exchanger, the temperature at the inlet of the heat exchanger inner tubes is higher than or equal to the dew point of water, and the gas to be cooled is cooled such that the temperature at the outlet of the heat exchanger inner tubes becomes lower than or equal to the dew point of water.

3. The production method according to claim 1 , wherein
the concentration of the chlorine compound in the raw material gas is from 0.01 ppm by volume to 1,000 ppm by volume based on the volume of the raw material gas.

4. The production method according to claim 1 , wherein
in the heat exchanger, a heat-absorbing medium for cooling the gas to be cooled is a gas comprising ethylene, molecular oxygen, and a chlorine compound.

5. The production method according to claim 1 , wherein
the heat exchanger is a multitubular heat exchanger.

6. The production method according to claim 1 , wherein
the stainless steel is at least one selected from the group consisting of martensitic stainless steels, ferritic stainless steels, austnitic stainless steels and precipitation hardening type stainless steels.

7. A method for producing ethylene oxide, the method comprising:
supplying a raw material gas comprising ethylene, molecular oxygen, and a chlorine compound to an ethylene oxidation reactor;
subjecting the ethylene and the molecular oxygen in the raw material gas to catalytic vapor phase oxidation in the ethylene oxidation reactor in the presence of a silver catalyst, and thereby producing a gas comprising ethylene oxide, water, and a chlorine compound; and
cooling a gas to be cooled comprising the water and the chlorine compound using a heat exchanger,
wherein in the heat exchanger, the gas to be cooled is cooled at a linear gas velocity on the heat exchanger inner tube side of 7 m/s or higher,
wherein the heat exchanger inner tubes are made of stainless steel, and the stainless steel is at least one selected from the group consisting of SUS403, SUS410, SUS410J1, SUS410F2, SUS416, SUS420J1, SUS420J2, SUS420F, SUS420F2, SUS431, SUS440A, SUS440B, SUS440C, SUS440F, SUS405, SUS410L, SUS430, SUS430F, SUS434, SUS201, SUS202, SUS301, SUS302, SUS303, SUS303Se, SUS303Cu, SUS304, SUS304L, SUS304N1, SUS304N2, SUS304LN, SUS304J3, SUS305, SUS309S, SUS321, SUS347, SUS630 and SUS631.

8. The production method according to claim 7 , wherein
the stainless steel is at least one selected from the group consisting of SUS403, SUS410, SUS410J1, SUS410F2, SUS416, SUS420.11, SUS420J2, SUS420F, SUS420F2, SUS431, SUS405, SUS410L, SUS430, SUS201, SUS301, SUS630 and SUS631.

9. The production method according to claim 7 , wherein
in the heat exchanger, the temperature at the inlet of the heat exchanger inner tubes is higher than or equal to the dew point of water, and the gas to be cooled is cooled such that the temperature at the outlet of the heat exchanger inner tubes becomes lower than or equal to the dew point of water.

10. The production method according to claim 7 , wherein
the concentration of the chlorine compound in the raw material gas is from 0.01 ppm by volume to 1,000 ppm by volume based on the volume of the raw material gas.

11. The production method according to claim 7 , wherein
in the heat exchanger, a heat-absorbing medium for cooling the gas to be cooled is a gas comprising ethylene, molecular oxygen, and a chlorine compound.

12. The production method according to claim 7 , wherein
the heat exchanger is a multitubular heat exchanger.

Assignees

• Nippon Catalytic Chem Ind

Inventors

• Iguchi Shingo
• Suzuki Hideto

Classifications

• C07D301/10 Primary

  with catalysts containing silver or gold · CPC title

• F28D15/02

  in which the medium condenses and evaporates, e.g. heat pipes {(heat pipes used in solar heat collectors F24S10/95; in radiators F28D1/0226; in nuclear reactors G21C15/257)} · CPC title

• F28F21/083

  from stainless steel · CPC title

• C07D303/04

  containing only hydrogen and carbon atoms in addition to the ring oxygen atoms · CPC title