Distillation (topic)

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Chapter 1 Distillation 1. True or False Questions 1. The calculation basis for full tower efficiency and single plate efficiency is the same, and both are discussed based on the concept of the number of theoretical plates required. (×) 2. The greater the relative volatility, the further the phase equilibrium curve deviates from the diagonal, and the more difficult the separation becomes. (×) 3. Mixing of materials with different compositions, that is, back-mixing, is an unfavorable engineering factor for the separation process. (√) 4. For the distillation tower, if the operating pressure in the tower is reduced, the boiling temperature of the liquid can be reduced, thereby avoiding the use of high-temperature heat transfer media in the reboiler. (√) 5. When the distillation tower is fully refluxing, its reflux ratio is infinite, and the whole tower is not divided into a rectifying section and a stripping section. (√ ) 6. In the total condenser, the gas and liquid phases are in gas-liquid equilibrium, so the total condenser is equivalent to a theoretical plate. (×) 7. The value of the reflux ratio is selected by the designer. From the perspective of energy consumption, the lower limit should be set, and the higher limit should be set for material systems that are difficult to separate. (√) 8. During the distillation operation, due to the long liquid flow path on the tray, there is an obvious concentration difference on the tray, which makes the gas distribution uneven and may cause the single plate efficiency of the tray to exceed 100%. (√) 9. Simple distillation, also known as differential distillation, is also a single-stage distillation process. (√) 10. The relationship between the compositions of the gas and liquid phases at equilibrium is called phase equilibrium relationship. It depends on the thermodynamic properties of the system and is the thermodynamic basis and basic basis of the distillation process. (√) 12. The difference in volatilization ability between components in a mixture is defined as relative volatility. (×) 13. Simple distillation is also called differential distillation and is an intermittent operation process. (√) 14. The distillation process in which the liquid phase (or gas phase) mixture is continuously flashed or expanded through throttling or the mixed gas is partially condensed so that the flow reaches primary equilibrium is called simple distillation. (×) 15. Continuous distillation is widely used in industrial production such as petroleum, chemical industry, light industry, etc., and is the preferred separation method for the separation of liquid mixtures. (√) 16. Simple distillation is equivalent to using one theoretical plate for distillation in batches multiple times, so the same theoretical plate works many times. (√) 17. Flash evaporation is equivalent to the total feed passing through one theoretical plate at a time for secondary separation. The separation effect is not as good as simple distillation. (√) 18. During the distillation process, the heat transfer and mass transfer processes are carried out at the same time, which is a mass transfer process control. (√) Light component products. (√) 19. In the rectification section, as the gas phase rises, the light components of the gas phase are continuously refined and concentrated in the gas phase, and are obtained at the top of the tower. 20. In the stripping section, as the liquid phase descends, the light components are continuously distilled out, so that the heavy components are continuously concentrated in the liquid phase, and the heavy components are obtained at the bottom of the tower. (√) 21. The biggest difference between the distillation process and other distillation processes is that both ends of the tower provide higher purity liquid phase and gas phase reflux at the same time, which provides the necessary conditions for mass transfer in the distillation process. (√) 22. Theoretical trays can be used as a benchmark to measure the actual tray separation effect, and the difference between them can be corrected by tray efficiency. (√) 23. The distillation tower is a device that provides contact conditions for the gas and liquid mixtures and realizes the mass transfer process. (√) 24. Simple continuous distillation tower refers to a conventional continuous distillation tower with a condenser at the top and a reboiler at the bottom. It has a feed and separates two products at the top and bottom. (√) 25. During the distillation process, if materials are fed at a suitable location, the number of plates required to complete the specified separation requirements will be reduced. For a given theoretical plate, separation 26 and reflux ratio R are important parameters for the design and operation of the distillation process. R directly affects the separation capacity of the distillation tower and the energy consumption of the system, and the degree will increase. (√) It also affects the structural size of the equipment. (√) 27. The efficiency of the total distillation plate reflects the overall situation of the entire tower and cannot reflect the efficiency of a certain section or plate. (√) 28. For non-ideal solutions with a constant boiling point, the method of adding a mass separation agent, that is, a carrier agent, and one or several components of the original solution to form an azeotrope with a lower boiling point, so that the original solution can be easily separated by distillation, is called azeotropic distillation. (√) 29. The extraction agent for extractive distillation must form the lowest azeotrope with the separated components, so it is not easy to select the extraction agent. The selection of entrainers for azeotropic distillation is much wider. (×) 30. In azeotropic distillation, the entrainer leaves the tower in a vapor state, which consumes more latent heat. However, the extraction agent in extractive distillation basically does not change. Generally speaking, extractive distillation is more economical. (√) 31. When the total pressure is constant, the composition and temperature of the azeotropic substance formed by azeotropic distillation are constant. (√) 32. The operating temperature of azeotropic distillation is generally lower than that of extractive distillation, so it is suitable for separating heat-sensitive materials. (√) 33. The principle of multi-component distillation is exactly the same as that of two-component distillation. Two-Component DistillationMany conceptual treatments can also be used in multi-component distillation. (√) 2. Multiple choice questions 1. Distillation is the unit operation of separating ( ) a mixture. BA gas ； B liquid ； C solid ； D rigid body. 2． Distillation is the purpose of separation using the ( ) different characteristics of each component. CA solubility ； B and other regulations ； C Volatility ； D Harmony. 3． In a binary mixture, the components ( ) are called volatile components. AA has low boiling point ； B has a high boiling point ； C Boiling point is constant ； D Boiling point change. 4． In a binary mixture, the component with a low boiling point is called the ( ) component. CA is volatile ； B Not volatile ； C Volatile ； D Difficult to evaporate. 5. In a binary mixture, the component ( ) is called a less volatile component. BA has low boiling point ； B has a high boiling point ； C Boiling point is constant ； D Boiling point change. 6． In a binary mixture, the component with a high boiling point is called the ( ) component. DA is volatile ； B Not volatile ； C Volatile ； D Difficult to evaporate. 7. ( ) is one of the essential conditions to ensure the continuous and stable operation of the distillation process. AA liquid phase reflux ； B feed ； C lateral line extraction ； D Product purification. 8. Liquid phase reflux is one of the essential conditions to ensure the continuous and stable operation of the ( ) process. BA absorption ； B Distillation ； C heat transfer ； D filter. 9. In ( ), the solution is partially vaporized to produce rising steam, which is an essential condition for the continuous and stable operation of distillation. CA condenser ； B evaporator ； C reboiler ； D heat exchanger. 10. The rising steam produced by the solution ( ) in the reboiler is an essential condition for the continuous and stable operation of distillation. C 11. Partial vaporization of the solution in the reboiler ( ) is produced, which is an essential condition for the continuous and stable operation of distillation. DA partially condensed ； B all condensed ； C partial gasification ； D All vaporize. 12. The function of the reboiler is to provide a certain amount of ( ) flow. DA rising material ； B rising component ； C rising products ； D rising vapor. A rising material ； B rising component ； C rising products ； D rising vapor. 13. The function of ( ) is to provide a certain amount of rising steam flow. CA condenser ； B evaporator ； C reboiler ； D heat exchanger. 14. The function of ( ) is to provide liquid phase products at the top of the tower and ensure appropriate liquid phase reflux. AA condenser ； B evaporator ； C reboiler ； D heat exchanger. 15. The function of the condenser is to provide ( ) products and ensure appropriate liquid phase reflux. BA top gas phase ； B top liquid phase ； C gas phase at the bottom of tower ； D liquid phase at the bottom of the tower. 16. The function of the condenser is to provide liquid phase products at the top of the tower and ensure appropriate ( ) reflux. BA gas phase ； B liquid phase ； C solid phase ； D mixed phase. 17. In the distillation tower, the plate into which the raw material liquid enters is called ( ). CA float valve plate ； B jet plate ； C feeding plate ； D separator plate. 18. In the distillation column, the column section above the feeding plate is called ( ). AA distillation section ； B stripping section ； C feed section ； D mixing section. 19. In the distillation tower, the column section below the feeding plate (including the feeding plate) is called ( ). BA distillation section ； B stripping section ； C feed section ； D mixing section. 20. In the distillation column, the column section with the feeding plate ( ) is called the distillation section. AA and above ； Below B ； Other than C ； Within D. twenty one. In the distillation column, the column section of the feeding plate ( ) (including the feeding plate) is called the stripping section. BA or above ； Below B ； Other than C ； Within D. twenty two. ( ) means that the gas and liquid phases leaving this plate are in equilibrium with each other, and the composition of the liquid phase on the plate can also be considered uniform. CA float valve plate ； B jet plate ； C theory board ； D separator plate. twenty three. The theoretical plate means that the ( ) leaving this plate are in equilibrium with each other, and the liquid phase composition on the plate can also be considered uniform. DA gas-solid two-phase ； B liquid-solid two phases ； C gas, liquid and solid three phases ； D gas and liquid two phases. twenty four. Theoretical plate refers to ( ) the gas and liquid phases of this plate are in equilibrium with each other, and the liquid phase composition on the tower plate can also be considered uniform. A leave ； B enter ； C mix ； D contact. A 25. The theoretical plate refers to the gas and liquid phases leaving this plate ( ), and the liquid phase composition on the plate can also be considered uniform. BA mix ； B into equilibrium ； C contact ； D separation. 26． The ( ) value of the reflow ratio is total reflow. AA cap ； B lower limit ； C average ； D mix. 27． The upper limit of the reflux ratio is ( ). Reflux within CA ； B external reflux ； C full reflow ； D minimum reflux ratio. 28． The ( ) value of the reflux ratio is the minimum reflux ratio. BA upper limit ； B lower limit ； C average ； D mix. 29. The lower limit of the reflux ratio is ( ). Reflux within DA ； B external reflux ； C full reflow ； D minimum reflux ratio. 30. For a certain binary mixture, the feed rate is 100 kmol/h, xF = 0.6, and the xD at the top of the tower is required to be not less than 0.9, then the maximum output at the top of the tower is ( ). BA 60kmol/h ； B 66.7 kmol/h ； C 90 kmol/h ； D 100 kmol/h. 3. Fill in the blanks 1. α=2 of the ideal physical system, in total reflow operation. It is known that yn=0.5 on a certain theoretical board, then yn+1= . 2. Intermittent distillation only has sections, but no stages. 3. Both azeotropic distillation and extractive distillation require the addition of a third component to the mixed liquid for the purpose of. 4. The main difference between simple distillation and equilibrium distillation. The main difference between simple distillation and batch distillation is. 5. The vapor-liquid relationship of a certain AB mixture is as shown in the figure: (1) Compare T1 T2, T3 T4, (>, =,