【Daily Question】What is bubble entrainment, and what are its hazards?
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This post was last edited by springpang on 2015-6-4 08:32. The Mechanical Section has introduced the \"Question of the Day\" feature, which not only helps to foster an active atmosphere for technical discussions and guide the direction of such exchanges but also provides users with financial rewards, enabling them to experience various cool features. Topic: What is bubble entrainment, and what are its hazards? The liquid flows horizontally across the tray; after coming into contact with the gas, it flows down to the lower tray through the downcomer. When the liquid flows into the downcomer, it often contains a large number of bubbles. It stays in the downcomer long enough for the foam to separate into gas and clear liquid, with the gas rising back to the upper tray. If the liquid load increases, the flow velocity of the liquid in the downcomer rises and its residence time becomes very short; as a result, the bubbles entrained in the liquid do not have enough time to separate before being carried to the next tray. This phenomenon is known as \"bubble entrainment\". What are its disadvantages? Answer: Severe bubble entrainment also reduces the separation efficiency of the tray, so it is also not allowed. The main measure to prevent bubble entrainment is to control the reflux mother liquor. Requirements and tips for answering: (You can summarize based on your own usage experience.) Please note: We will close this thread after 24 hours, and at that time we will announce the best answer (the most helpful response), along with the solution and explanation. Charisma Reward: If you post a topic in this section within two days to provide a detailed explanation of the knowledge points related to this question, please reply to this post to inform us, and we will have a moderator grant you +Charisma. It is not allowed to simply copy and paste; original content is preferred, with at least some organization by the user along with personal insights. After registration, we will rank based on the content of the posts: the last-place contestant will receive +1 charm, the second-to-last +2 charm, and so on, with the highest score earning +5 charm. Other content: Recruitment for moderators, promotions for sections or regions (must be included), solicitation of topics, etc. 【Mechanical Zone】Call for a Comprehensive Collection of Essential Knowledge 【Seeking Manufacturer Sponsorship】 (Ongoing campaign) 【Rewards for Recommending Essential Content】
Bubble entrainment: Hazard – reduces the throughput capacity of the downcomer； Preventive measures: Ensure the residence time of the liquid in the downcomer
What is bubble entrainment, and what are its hazards? The liquid flows horizontally across the tray; after coming into contact with the gas, it flows down to the lower tray through the downcomer. When the liquid flows into the downcomer, it often contains a large number of bubbles. It stays in the downcomer long enough for the foam to separate into gas and clear liquid, with the gas rising back to the upper tray. If the liquid load increases, the flow velocity of the liquid in the downcomer rises and its residence time becomes very short; as a result, the bubbles entrained in the liquid do not have enough time to separate before being carried to the next tray. This phenomenon is known as \"bubble entrainment\". Severe bubble entrainment reduces the separation efficiency of the tray, so it is not allowed. The measure to prevent bubble entrainment is to control the reflux flow properly.
Bubble entrainment: The liquid flows horizontally across the tray; after coming into contact with the gas, it moves to the lower tray through the downcomer. When liquid flows into the downcomer, it often contains a large number of bubbles. These bubbles stay in the downcomer long enough for the foam to separate into gas and clear liquid, with the gas rising back to the upper trays of the tower. If the liquid load increases, the flow velocity of the liquid in the downcomer rises and its residence time becomes very short; as a result, the bubbles entrained in the liquid do not have enough time to separate before being carried to the next tray. This phenomenon is known as \"bubble entrainment\". Hazard: Severe bubble entrainment can also reduce the separation efficiency of the tray. Main control methods: The primary measure to prevent bubble entrainment is to control the backflow rate.
Reduce the throughput capacity of the downcomer. In severe cases, regurgitation of saliva may occur.
The liquid flows horizontally across the tray; after coming into contact with the gas, it flows down to the lower tray through the downcomer. When the liquid flows into the downcomer, it often contains a large number of bubbles. It stays in the downcomer long enough for the foam to separate into gas and clear liquid, with the gas rising back to the upper tray. If the liquid load increases, the flow velocity of the liquid in the downcomer rises, resulting in a short residence time; the bubbles entrained in the liquid do not have enough time to separate before being carried to the next tray. This phenomenon is known as \"bubble entrainment.\" Its occurrence leads to an increase in the pressure drop within the tower and a decrease in the temperature at the bottom of the tower, which can result in flooding of the tower!
It generally refers to the liquid on the tray in a plate tower being carried upward to the next tray by the rising gas (or vapor). As the gas passes upward through the liquid layer on the tray, the liquid forms mist droplets under the action of the gas flow. As the airflow rises, larger droplets return to the liquid layer under the influence of gravity, while smaller mist particles are carried by the gas flow to the upper trays. Foam entrainment causes backmixing of the liquid between the tray levels, thereby reducing the separation efficiency. . Foam entrainment often leads to a decrease in the efficiency of the tray, and its influencing factors include high processing volume, small spacing between trays, and the structure of the trays. The hazards of Wu Mo entrainment: The consequence is liquid carried in the vapor phase, resulting in an increased content of heavy components in the product at the top of the tower; in severe cases, this can lead to flooding.
Gas-phase mixing on the tray. This leads to a decrease in mass transfer efficiency.
In simple terms, it means that the bubbles contained in the liquid do not have time to separate and are carried to the next tray of the tower; this phenomenon is known as \"bubble entrainment\". Disadvantage: Reduces the separation efficiency of the tray.
The separation effect of light and heavy components is poor!
The liquid flows horizontally across the tray; after coming into contact with the gas, it flows down to the lower tray through the downcomer. When the liquid flows into the downcomer, it often contains a large number of bubbles. It stays in the downcomer long enough for the foam to separate into gas and clear liquid, with the gas rising back to the upper tray. If the liquid load increases, the flow velocity of the liquid in the downcomer rises and its residence time becomes very short; as a result, the bubbles contained within the liquid do not have enough time to separate before being carried to the next tray. This phenomenon is known as \"bubble entrainment\"”