Unlock instant, AI-driven research and patent intelligence for your innovation.

A process for initiating a highly selective ethylene oxide catalyst

A catalyst, ethylene technology, applied in the direction of physical/chemical process catalysts, metal/metal oxide/metal hydroxide catalysts, chemical instruments and methods, etc., can solve the problems that do not mention the impregnation step of the moderator

Inactive Publication Date: 2015-05-20
SCI DESIGN
View PDF18 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There is no mention of moderator impregnation step in this invention publication

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A process for initiating a highly selective ethylene oxide catalyst
  • A process for initiating a highly selective ethylene oxide catalyst
  • A process for initiating a highly selective ethylene oxide catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0006] It has been disclosed in the prior art that the start-up of highly selective silver-based catalysts for ethylene oxidation requires a special method and procedure, which takes an extended period of time to complete at high temperatures. The presence of moderator in the feed was reported to be insignificant to the reported conditioning.

[0007] The applicant of the present application has found that starting the dosing procedure before raising this temperature will result in a supersaturated condition. On the other hand, after the heating up time, to the conditioning temperature, dosing the catalyst will lead to runaway reactions in the early stages of the conditioning phase. The present invention provides a method that avoids the problems associated with starting this dosing program too early or too late. The applicants of the present application have found that the "conditioning" of such highly selective silver-based catalysts, especially if they contain Re as co-cat...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A start-up process for epoxidation of ethylene is provided. The process includes initiating an epoxidation reaction by reacting a feed gas composition in the presence of an epoxidation catalyst at a first temperature of about 180° C. to about 210° C. The first temperature is increased to a second temperature of about 230° C. to about 290° C., over a time period of about 6 hours to about 50 hours, while simultaneously adding a sufficient concentration of moderator so that the amount of moderator adsorbed on the catalyst after achieving the second temperature is from about 10 to about 50 g / m3 of catalyst. The second temperature is maintained for about 50 hours to about 350 hours, while regulating the feed gas composition to contain about 0.5% to about 25% CO2. The second temperature is decreased to a third temperature, while simultaneously increasing moderator concentration to a level greater than the sufficient concentration.

Description

Background technique [0001] The start-up of highly selective silver-based catalysts for ethylene oxidation requires special methods and procedures. Such catalysts, especially when they contain Re as a cocatalyst, require an initiation period before they can provide the expected high performance. In the prior art, US Patent No. 4,874,879 to Lauritzen and US Patent No. 5,155,242 to P. Shankar, both disclose prechlorination of fresh Re-containing catalysts prior to adding oxygen to the feed. In these disclosures, the catalyst is first prechlorinated with a feed gas containing ethylene, methane and ethyl chloride. Oxygen was added to the feed thereafter and the reaction temperature was kept below 273°C. In practice several adjustments to the reaction conditions are made to provide optimum performance. This prechlorination step, which is claimed to enhance the activity of rhenium-containing catalysts, allows low temperature initiation (start-up). [0002] Other priming techniqu...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07D301/10C07C11/04
CPCC07D301/10B01J23/36C07C11/04C07D301/03C07D303/04
Inventor 纳比勒·里兹卡拉诺尔玛·B·卡斯塔尼奥拉吉里什·德赛
Owner SCI DESIGN