VIETNAM NATIONAL UNIVERSITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY FACULTY OF CHEMICAL ENGINEERING PROCESSES AND EQUIPMENT DEPARTMENT ACKNOWLEDGEMENT First of all, I am extremely grateful to my ins[.]
VIETNAM NATIONAL UNIVERSITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY FACULTY OF CHEMICAL ENGINEERING PROCESSES AND EQUIPMENT DEPARTMENT ACKNOWLEDGEMENT First of all, I am extremely grateful to my instructor Dr Tran Tan Viet, despite his busy schedule, he always arranges time to support, encourage and equip me through realistic, professional and useful feedback on topics associated with design Besides, I would like to express my deepest thanks to my teachers of Process and Equipment Department for providing me a body of knowledge regards to material and energy balances, thermodynamics, fluid mechanics, heat transfer, mass transfer, separation technologies, chemical reaction kinetics, reactor and process design so that I could complete this project about designing a real distillation column In process of finishing the project, it might include mistakes, I would like to receive advices as well as suggestions from the teachers Finally, I wish the teachers always have good health and happiness Tran Tan Viet HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY SOCIAL REPUBLIC OF VIETNAM Faculty of Chemical Engineering Independence – Freedom – Happiness Department of Process and Equipment Student name: Ngô Tường Vỹ Student number: 1852890 Title: Designing the continuous distillation of a binary mixture BenzeneToluene using bubble cap tray column. First Requirements Feed capacity: 125 kmole/hr Feed concentration: 15% (molar) Overhead product concentration: 97% (molar) Contents of the explanation and calculation Overview Describe the technology process Calculating material and energy balance Calculating and designing the main equipment Calculating and selecting auxiliary equipments Drawing and diagrams Technology process drawing in size A1. Main equipment assembly drawing in size A1. Project – receiving date: 8/ Sep /2022. Complete date: Head of Department Assoc.Prof Ph.D Trịnh Văn Dũng Instructor Ph.D Trần Tấn Việt Contents CHAPTER THEORY 1.1 Distillation definition 1.2 Distillation method classification 1.3 Distillation equipment .7 1.4 Benzene 1.5 Toluene 1.6 Vapor-Liquid Diagram 10 CHAPTER MASS BALANCE 12 2.1 Plug-flow diagram 12 2.2 Find the molar capacity 13 2.3 Reflux ratio 14 2.4 Number of theorical tray .15 2.5 Actual number of trays 17 CHAPTER ENERGY BALANCE .19 Energy balance for the column 19 3.1 Energy balance for Feed-preheating equipment 19 3.2 Energy balance for overhead condenser .21 3.3 Energy balance for bottom reboiler 22 3.4 Energy balance in cooler for bottom product 23 3.5 Energy balance in overhead product cooler 23 CHAPTER CALCULATION FOR DISTILLATION COLUMN .25 4.1 Diameter of tower 25 4.1.1 Rectifying section 25 4.1.2 Stripping section .28 4.2 The height of distillation column 31 4.3 The height of the bottom and the head: 32 4.4 Bubble cap calculation: 32 4.5 The weir calculation 36 4.6 Surface tension resistance .37 4.7 Flooding test 42 CHAPTER MECHANICAL DESIGN .47 5.1 Material: 47 5.2 The thickness of body of distillation column: .47 5.3 The thickness of the bottom and the head of distillation column 50 5.4 The flange .50 5.4.1 The flange connected to the body of the column 54 5.4.2 The flange connected between part of the device and the pipes 56 5.5 The supports: 57 CHAPTER AUXILIARY EQUIPMENT 60 6.1 Feed preheater: 60 6.2 Reboiler 66 6.3 Condenser .71 REFERENCES 77 CHAPTER THEORY 1.1 Distillation definition Distillation is a purifying process which is used to separate components in a liquid mixture or liquid-gas mixture, basing on the volatility of each component This technique can be used to either increase the concentration of a particular component in a mixture or obtain pure components from the mixture Instead of introducing a new substance into the mixture in order to create the second phase, as is done in absorption or desorption, the new phase is created from the original solution by vaporization or condensation Considering a simple mixture with components, we have The top product consists of a large amount of most volatile component and very small amount of less volatile component/ The bottom product consists of a large amount of less volatile component and a very small amount of most volatile component In distillation, if we consider only binary system for Benzene-Toluene, distillate products are mostly benzene and a small fraction of toluene, whereas the bottom products are mainly toluene and some remaining benzene 1.2 Distillation method classification Basing on working pressure: low-pressure distillation, normal-pressure distillation and high-pressure distillation The basic fundamental is based on the boiling point of the components, if the Boling point is too high, we need to reduce the working pressure to decrease the Boling point of the components Basing on heat: Direct heat-supplying distillation Indirect heat-supplying distillation Basing on working principles Steam distillation Simple distillation Fractional distillation 1.3 Distillation equipment In manufacturing, different types of distillation equipment are used However, they all have basic requirement that is the area of contacted phase surface must be large, depending on the dispersion of this fluid into the other fluid There are two main types of columns, batch and continuous distillation column We investigate two types of distillation towers commonly used in continuous distillation, which are Tray towers and packed towers In term of tray column, sieve trays and bubble cap trays are mostly widespread Tray tower: The cylindrical vertical body of the tower, which sticks Trays having different structures in the interior to split the body of the tower into equal segments, on the Trays liquid phase and the vapor phase are exposed to each other Depending on the composition of the plates, includes: Bubble cap trays column: on Trays having bubble cap having form of circle, S,… The structure is surrounded by grooves to pass the gas through and the transmission pipeline Sieve Tray column: on Tray having holes having diameter of (3-12 mm) distribution Packed column: A cylindrical tower, consisting of several segments connected by flanges or welding Packings are placed in the tower in one of two methods: random or sequential In this case, bubble caps tray is chosen for Benzene-Toluene mixture distillation This type consists of some advantages: High efficiency, stable operation, less energy consumption, so there are few trays required 1.4 Benzene Benzene (C6H6) is a clear, colorless, highly flammable and volatile, liquid aromatic hydrocarbon with a gasoline-like odor Benzene is non-polar, so it dissolves greatly in organic solvent and very weekly in water Benzene is found in crude oils and as a byproduct of oil-refining processes In industry benzene is used as a solvent, as a chemical intermediate, and is used in the synthesis of numerous chemicals However, nowadays, benzene is no longer using widely, because it is found that small concentration benzene in air can cause some blood diseases Figure 1.1 Structure of benzene Table Physical properties of benzene Molar mass 78.11 g/mol Density 0.874 g/mL at 25 Boiling point 80 Melting point 5.5 Dynamic viscosity 0.6603 cP Kinetic viscosity 0.751x10-6 m^2/s 1.5 Toluene Toluene is a colorless, water-insoluble liquid with the smell associated with paint thinners It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group Toluene is non-polar, so it is greatly soluble in benzene Toluene has solvent properties like benzene but less toxic, so it widely is used as solvent in labs and industries Figure 1.2 Structure of Toluene Table 1.2 Physcial properties of toluene Molar mass 92.13 Density 0.866 g/mL at 20 Boiling point 111 Melting point -95 Dynamic viscosity 0.59 cP at 20 Kinetic viscosity at 20C 1.6 Vapor-Liquid Diagram Table 1.3 Tx-y data for benzene-toluene binary mixture x y T 0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.118 0.214 0.38 0.511 0.619 0.712 0.79 0.854 0.91 0.959 110.6 108.3 106.1 102.2 98.6 95.2 92.1 89.4 86.8 84.4 82.3 80.2 Figure 1.4 VLE diagram of benzene-toluene tixture Figure 1.5 Tx-y diagram of benzene-toluene binary mixture