What are the factors affecting the process of oxidizing ethylene to ethylene oxide?

2. Reaction pressure: Changes in reaction pressure can also affect the process. Generally, the higher the pressure, the faster the reaction rate, but equipment and safety issues associated with excessively high pressures must be taken into account. The normal operating pressure is between 1.5 and 3.0 MPa. 3. Reaction time: Reaction time is also one of the influencing factors. Too short a reaction time reduces the conversion rate, while too long a reaction time lowers the product yield and the catalyst lifespan. Under normal circumstances, the reaction time is kept between 40 and 60 minutes. 4. Type and amount of catalyst: Choosing the appropriate type and amount of catalyst has a significant impact on the reaction’s conversion rate, selectivity, and process stability. The amount of catalyst used must be adjusted according to the properties of different catalysts. 5. Gas flow ratio: Adjusting the gas flow ratio can affect the distribution of various components within the reactor, which in turn influences the reaction rate and conversion rate. An appropriate gas flow ratio can improve product yield and catalyst lifespan. 6. Waste gas treatment method: The waste gas treatment method is also an important part of the process. Choosing the appropriate treatment method can reduce environmental pollution while lowering product costs. .

2. Pressure: Since the reaction does not involve equilibrium conversion rates, pressure has no significant effect on the reaction. For reasons such as product recycling and equipment volume, the pressure is usually set at around 2.0 MPa.

Thank you for the correction! Indeed, the effect of the pressure you mentioned on the reaction does not have a significant impact on the equilibrium conversion rate. However, in actual production, either too high or too low pressure can affect the reaction rate, conversion rate, and selectivity; therefore, it is necessary to pay attention to pressure control. At the same time, the equipment volume and product recycling you mentioned are also among the factors that need to be taken into account regarding pressure. .

3. Air velocity: Air velocity also has a significant impact on the reaction, second only to temperature. With a high space velocity and short residence time, if the reaction is controlled by surface reactions, the conversion rate decreases while selectivity increases. In industry, the space velocity for oxidation using air is generally 7000 h-, while that for oxidation using oxygen is 5500–7000 h-.

Thank you very much for your corrections and additions! The influence of the space velocity you mentioned on the reaction is indeed very important, and the space velocity required varies slightly depending on the oxidant used. By appropriately adjusting the space velocity, it is possible to control the reaction rate, conversion rate, and selectivity; therefore, the choice of space velocity is also a key factor affecting the process. .

4. Gas purity (toxic and harmful substances): Sulfides: cause catalyst poisoning； Acetylene: Causes catalyst poisoning ； Iron ions: cause a decrease in selectivity and lead to the formation of acetaldehyde ； Carbon dioxide: The heat of reaction increases.

Thank you so much for the additional information! The gas purity and toxic and harmful substances you mentioned are indeed also among the factors that affect the process. This is because impurities or unclean substances in the air can poison the catalysts inside the reactor, reducing their activity and thereby affecting the conversion rate and selectivity of the reaction. At the same time, the addition of certain gases can also increase the heat effect of the reaction, so it is necessary to pay attention to controlling these factors. .

5. Process gas ratio (mixed gas): Air is used as the oxidant; the ethylene content is around 5%, while the oxygen content is around 6%. Pure oxygen is used as the oxidant: with an ethylene content of around 20-30% and an oxygen content of around 7-8%. Carbon dioxide:

Thank you for the addition! Indeed, the ratio of process gases is also one of the factors affecting the process of oxidizing ethylene to ethylene oxide. When air is used as an oxidant, the ethylene content needs to be kept at around 5%, while the oxygen content should also be maintained at around 6%. When pure oxygen is used as an oxidant, the ethylene content can be increased to around 20-30%, while the oxygen content needs to be kept at around 7-8%. At the same time, the addition of carbon dioxide can be controlled by adjusting the gas flow rate in the reactor, thereby affecting the conversion and selectivity of the reaction. .