Ethylene epoxidation starting method

A technology for ethylene epoxidation and driving method, which is applied in chemical instruments and methods, metal/metal oxide/metal hydroxide catalysts, organic chemistry, etc. and other problems to achieve the effect of avoiding excessive local heat release, rapid selective pull-up, and stable activity improvement

Pending Publication Date: 2022-05-06
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] The inventors of the present invention found in the research that devices with high space-time yield, large pipe diameter and low space velocity have become the mainstream of design. If the existing start-up method is continued, problems such as overheating and tail burning are likely to occur, thereby As a result, it is impossible to drive normally, so adjustments must be made to the driving method
Solved the process problems such as sudden increase in catalyst activity, excessive local heat release, and slow increase in device load at the initial stage of start-up

Method used

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  • Ethylene epoxidation starting method
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Embodiment approach

[0024] According to a preferred embodiment of the invention, step S2 includes three stages:

[0025] In the first stage, the regulator is added before adding oxygen, the circulating gas is introduced into the reactor with 50% - 70% of the designed circulating gas volume, and the start-up is started at a constant temperature in the range of 220 ℃ - 235 ℃; Gradually accumulate the carbon dioxide produced by the reaction, so that the inlet carbon dioxide is 3mol% - 5mol%;

[0026] In the second stage, gradually increase the load of oxygen and ethylene to the target load. This step can quickly increase the load of oxygen and ethylene (give priority to increasing the oxygen load), and appropriately reduce the reaction temperature according to the change of reaction bed temperature to facilitate the rapid increase of load. Specifically, the reaction temperature can be optionally reduced by 5-15 ℃; At this time, the circulating gas volume has been restored to 100% of the design circulati...

Embodiment 1

[0054] 1. The catalyst was evaluated in the pilot plant. Preparation before oxygen dosing: before oxygen dosing, nitrogen is introduced into the reactor for replacement, so that the oxygen content in the gas leaving the reactor is less than 0.5%. When the oxygen content in the replacement gas leaving the reactor is less than 0.5%, fill nitrogen to increase the reactor pressure to 1.45-1.5mpa. The heating equipment of the unit is used to maintain the catalyst bed temperature above 230 ℃ for deamination treatment.

[0055] 2. Oxygen dosing preparation: the system keeps the reaction temperature at a constant temperature from 220 ℃ to about 235 ℃ (as 235 ℃ in Table 1), the system pressure is about 1.65mpa, the ethylene concentration is 15.0mol%, and remains stable. At this time, the circulating gas volume is maintained at 50% of the design circulating gas volume.

[0056] 3. For oxygen dosing reaction, refer to the start-up schedule (Table 1):

[0057] When the temperature, pressure a...

Embodiment 2

[0066] Ys series of highly selective silver catalysts were selected in a factory. Before the start-up of the unit, the reactor is filled with nitrogen to replace deamination: without starting the circulating gas compressor for gas circulation, isolate the reactor, introduce low-pressure nitrogen at the inlet of the reactor, punch the reactor to 0.1 ~ 0.5MPa, and raise the reactor temperature to 230 ℃ and keep it unchanged (control the heating rate to be less than 25 ℃ / h). Then exhaust at the low vent point at the outlet of the reactor to continuously discharge the amine removed from the catalyst. The amine content in the exhaust gas is detected once every 4 hours to monitor the change of amine content. The goal is that the amine concentration is significantly lower than the maximum value, and the whole deamination time is 24 ~ 48 hours. Make the unit preliminarily ready for feeding and start-up.

[0067] In the plant system, first put ethylene to 15mol% and keep the system stabl...

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Abstract

The invention belongs to the technical field of ethylene epoxidation, and relates to an ethylene epoxidation starting method. Comprising the following steps: S1, before start-up, preheating the bed temperature of a reactor to 230 DEG C or above, and introducing nitrogen to carry out deamination treatment on a catalyst; s2, feeding a feed gas containing ethylene, oxygen and a regulator at the reaction temperature of 220-235 DEG C, reacting to generate an ethylene oxide product and a by-product containing carbon dioxide under the action of the ethylene epoxidation high-selectivity silver catalyst, and returning a recycle gas containing the by-product carbon dioxide to the inlet of the reactor. According to the method disclosed by the invention, the load of the device can be smoothly increased to the full load required by the device within about 0-144 hours at the initial stage of starting the catalyst. According to the method, the selectivity of the catalyst is rapidly increased, the activity is stable, a foundation is laid for follow-up efficient and stable operation of the catalyst, in addition, the overall activity of the catalyst is stably improved in the driving process, and the problem that local heat release is too large is avoided.

Description

technical field [0001] The invention belongs to the field of ethylene epoxidation process, and relates to the process control problem in the process of preparing ethylene oxide and ethylene glycol by ethylene epoxidation. More specifically, it relates to a fast load lifting and selective ethylene epoxidation start-up method. Background technology [0002] Ethylene oxide is an important ethylene derivative. Because of its active chemical properties, it is an important chemical intermediate and organic solvent. It is widely used in the preparation of fungicides, antacids, plasticizers, emulsifiers and so on. Ethylene glycol is the main downstream product of ethylene oxide. It is also a widely used organic solvent and surfactant. At present, the market demand for ethylene oxide and ethylene glycol and its production capacity are increasing year by year, and its downstream market prospect is very broad. [0003] In the industrial reaction of epoxidation of ethylene to ethylene oxide,...

Claims

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Application Information

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IPC IPC(8): C07D301/10C07D303/04B01J23/656B01J37/08B01J8/00
CPCC07D301/10C07D303/04B01J23/6567B01J37/08B01J8/008
Inventor 蒋赛魏会娟李巍代武军蒋文贞汤之强王金秋崔迪
Owner CHINA PETROLEUM & CHEM CORP
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