Senior brothers and sisters, please help

I have in my QuPan a book titled \"Guide to the Selection and Design of Heat Exchangers\" as well as \"Comprehensive Book on Chemical Equipment Design: Heat Exchangers\"; you can take a look at them at http://zhangyong6404.qupan.com/

I. Design tasks and design conditions The process flow for a certain production process is shown in the figure. The mixed gas from the reactor is heated together with the feed stream; thereafter, it is cooled further from 110°C to 60°C using circulating cooling water, before entering the absorption tower where the soluble components are removed. Given that the flow rate of the mixed gas is 227,301 kg/h, the pressure is 6.9 MPa, the pressure of the circulating cooling water is 0.4 MPa, the inlet temperature of the circulating water is 29°C, and the outlet temperature is 39°C, design a shell-and-tube heat exchanger to carry out this production task. Physical properties: The relevant physical property data of the mixed gas at 35°C are as follows (based on measurements taken during production): Density, specific heat capacity at constant pressure = 3.297 kj/kg°C; thermal conductivity = 0.0279 W/m. Viscosity. Physical property data of circulating water at 34°C: Density = 994.3 kg/m³; specific heat capacity at constant pressure = 4.174 kj/kg°C; thermal conductivity = 0.624 W/m°C. Viscosity. II. Determination of the design scheme 1. Selection of the type of heat exchanger. Temperature changes in the two-flow system: inlet temperature of the hot fluid = 110°C, outlet temperature = 60°C℃ ； The inlet temperature of the cold fluid is 29°C, while the outlet temperature is 39°C. This heat exchanger is cooled by circulating cooling water; during operation in winter, its inlet temperature decreases. Taking this into account, it is estimated that the difference between the tube wall temperature and the shell temperature of this heat exchanger is significant. Therefore, a floating-head type heat exchanger is chosen as the appropriate option. 2. Tube side arrangement: Considering the operating pressures of the two fluids, the mixed gas should flow through the tube side, while the circulating cooling water should flow through the shell side. However, since circulating cooling water tends to scale easily, if its flow rate is too low, it will accelerate the growth of scale and reduce the heat transfer capacity of the heat exchanger; therefore, overall, the circulating water should flow through the tube side while the mixed gas flows through the shell side. III. Determination of physical property data – Qualitative temperature: For general gases and low-viscosity fluids such as water, the qualitative temperature can be taken as the average of the inlet and outlet temperatures of the fluid. Therefore, the qualitative temperature of the gas in the shell side is T = 85°C, while the qualitative temperature of the fluid in the tube side is t = °C. Based on these qualitative temperatures, the relevant property data for the fluids in the shell side and tube side can be obtained accordingly. For mixed gases, the most reliable qualitative data are the measured values. If this condition is not met, the relevant physical property data for the innocent components in the mixture must be obtained separately, and then the physical property data of the mixed gas shall be calculated using the appropriate addition methods. The relevant physical property data of the mixed gas at 35°C are as follows (based on measurements from actual production): Density, specific heat capacity at constant pressure = 3.297 kj/kg°C; thermal conductivity = 0.0279 W/m; viscosity = 1.5×10^-5 Pa·s. The physical property data of the circulating water at 34°C are: density = 994.3 kg/m³; specific heat capacity at constant pressure = 4.174 kj/kg°C; thermal conductivity = 0.624 W/m·°C; viscosity = 0.742×10^-3 Pa·s. IV. Estimation of the heat transfer area 1. Heat flow rate Q1 = 227301 × 3.297 × (110 – 60) = 3.75×10^7 kj/h = 10416.66 kW. 2. Average heat transfer temperature difference: Calculated using pure counterflow, this value is… 3. Heat transfer area: Due to the high pressure of the gas in the shell side, a larger value of K can be selected. Assuming K=320 W/(㎡·K), the estimated heat transfer area is Ap=4. The amount of cooling water required is m=. V. Dimensions of the process setup: 1. Pipe diameter and flow velocity inside the pipe: Higher-grade cold-drawn heat transfer pipes made of carbon steel with a diameter of Φ25×2.5 are used, with a flow velocity inside the pipe of u1=1.3 m/s. 2. The number of passages and the number of heat transfer tubes can be determined based on the inner diameter and flow velocity of the heat transfer tubes. The number of heat transfer tubes per passage is given by Ns; the length required for the heat transfer tubes, when calculated based on a single passage, is L. If the heat transfer tubes are too long, it is advisable to use a multi-pass structure. Based on the actual conditions of this design, a non-standard design approach is adopted. Here, the length of the heat transfer tubes is l = 7 m; thus, the number of tubes in the tube side of this heat exchanger is Np = Total number of heat transfer tubes Nt = 612 × 2 = 1224. 3. Correction for average heat transfer temperature difference and number of shell sides The correction coefficients for the average temperature difference are given by equations (3-13a) and (3-13b): R = P = For a single-shell, double-tube structure, referring to Figure 3-9, the average heat transfer temperature difference is determined. Since the correction coefficient for the average heat transfer temperature difference is greater than 0.8, and the flow rate of the fluid in the shell side is high, it is appropriate to use a single shell side. 4. Arrangement of heat transfer tubes and stage division method: The combined arrangement method is adopted, that is, the tubes are arranged in a regular triangle within each stage, while a square arrangement is used on both sides of the partition. See Figure 3-13. Taking the tube center distance as t=1.25d0, we have t=1.25×25=31.25≈32 mm. The distance from the center of the partition to the center of the nearest row of tubes is calculated using equation (3-16): S=t/2+6=32/2+6=22 mm. The tube center distance between adjacent tubes in each stage is 44 mm. For the method of dividing the number of tubes, there are 612 heat transfer tubes in each pass; the placement of partition plates at the front and back, as well as the sequence of flow of the medium, are determined according to Figure 3-14. 5. Shell inner diameter: A multi-pass structure is adopted, and the shell inner diameter can be estimated using equation (3-19). Taking the tube sheet utilization factor η = 0.75, the inner diameter of the shell is D = 1.05t; according to the progression levels for rolled shells, D can be set at 1400 mm. 6. Baffles: Arc-shaped baffles are used, and the height of the cutout in these arc-shaped baffles is 25% of the inner diameter of the shell. Thus, the height of the cutout is H = 0.25 × 1400 = 350 mm, so h can be taken as 350 mm. The spacing between the baffles, B, is set at 0.3D; therefore, B = 0.3 × 1400 = 420 mm, although 450 mm can also be used for this value. The number of baffle plates, NB = The baffle plates are arranged horizontally in a crescent shape, as shown in Figure 3-15. 7. Other attachments: The number and diameter of the tie rods shall be selected according to Table 3-9. The inner diameter of the shell of this heat exchanger is 1400 mm; therefore, the diameter of the tie rods should be Ф12, and the number of such tie rods must be at least 10. At the shell side inlet, an anti-scour baffle should be installed, as shown in Figure 3-17. 8. Nozzles: For the inlet and outlet nozzles of the shell-side fluid, assuming the gas flow velocity inside the nozzle is u1=10 m/s, the inner diameter of the nozzle can be rounded to 300 mm. Inlet and outlet nozzles for the fluid in the tube side: Assuming the flow velocity of the liquid inside the nozzle to be u2 = 2.5 m/s, the inner diameter of the nozzle is rounded to 360 mm. 6. Heat exchanger calculation 1. Heat transfer rate calculation (1) Heat transfer coefficient on the shell side: Calculated using Kern’s method, as shown in equation (3-22). The equivalent diameter is obtained from equation (3-23b). The cross-sectional area available for fluid flow on the shell side is determined using equation 3-25. The flow velocity of the fluid on the shell side and its Reynolds number are as follows; the Prandtl number and viscosity correction values are also calculated accordingly. (2) Heat transfer coefficient on the inner surface of the tubes: Using equations 3-32 and 3-33, the cross-sectional area available for fluid flow inside the tubes can be determined. The flow velocity of the fluid inside the tubes and its Prandtl number are also calculated. (3) Fouling heat resistance and wall heat resistance: According to Table 3-10, the fouling heat resistance on the outside of the tubes and the fouling heat resistance on the inside of the tubes can be determined. The wall heat resistance is calculated using equation 3-34; according to Table 3-14, the thermal conductivity of carbon steel under these conditions is 50 W/(m•K). Therefore, (4) the heat transfer coefficient is given by equation 3-21. (5) The heat transfer area margin can be determined using equation 3-35; the calculated heat transfer area Ac represents the actual heat transfer area Ap of this heat exchanger. The area margin of this heat exchanger is as follows: if the heat transfer area margin is sufficient, then the heat exchanger is capable of fulfilling its production tasks. 2. Wall temperature calculation: Since the tube wall is very thin and its thermal resistance is low, the wall temperature can be calculated using equation 3-42. Since this heat exchanger is cooled by circulating water, during operation in winter, the inlet temperature of the circulating water will decrease. To ensure reliability, the wall temperature of the heat transfer tube is calculated using an inlet temperature of 15°C and an outlet temperature of 39°C for the circulating cooling water. Furthermore, the high thermal resistance of fouling on the inside of the heat transfer tubes causes the wall temperature of these tubes to rise, thereby reducing the temperature difference between the shell and the tube walls. However, in the early stages of operation, the fouling thermal resistance is low, and the temperature difference between the shell and the heat transfer tubes may be large. In the calculations, the most unfavorable operating conditions should be considered; therefore, the fouling thermal resistances on both sides are taken as zero when calculating the wall temperature of the heat transfer tube. Thus, according to equation 4-42, the average temperature of the liquid and the average temperature of the gas are calculated as follows: 0.4×39 + 0.6×15 = 24.6°C, and (110 + 60)/2 = 85°C. The heat transfer coefficient is 5887 W/㎡•K, while that for the shell wall is 925.5 W/㎡•K. The average wall temperature of the heat transfer tubes is …°C; the wall temperature of the shell can be approximated as the average temperature of the fluid flowing in the shell side, i.e., T = 85°C. The difference between the shell wall temperature and the heat transfer tube wall temperature is ℃. The temperature difference is large, so a temperature compensation device is required. Due to the high pressure in the shell side of the heat exchanger, it is more appropriate to use a floating-head heat exchanger. 3. Flow resistance of the fluid inside the heat exchanger: (1) Fluid resistance in the tube side – with Re=35002 and a roughness of 0.01 for the heat transfer tubes, the velocity u is 1.306 m/s as determined from the Chaudhry chart; therefore, the fluid resistance in the tube side is within the acceptable range. (2) Shell-side resistance: It is calculated using the following formula. The resistance to fluid flow through the tube bundle is F = 0.5 × 0.2419 × 38.5 × (14 + 1) = 75,468 Pa. The resistance to fluid flow through the gaps in the baffle plates is given by B = 0.45 m, D = 1.4 m; thus, this resistance equals 43,218 Pa. The total resistance is therefore 75,468 + 43,218 = 119,686 Pa. Since the operating pressure of the fluid in the shell side of this heat exchanger is relatively high, the resistance associated with that fluid is also at an appropriate level. (3) The main structural dimensions and calculation results of the heat exchanger are shown in the table below:
Parameters: Tube side, Shell side; Flow rate: 898560, 227301; Inlet/outlet temperature/°C: 29/39, 110/60; Pressure/MPa: 0.4, 6.9; Properties: Qualitative temperature/°C: 34, 85; Density/(kg/m³): 994.3, 90; Specific heat at constant pressure/: 4.174, 3.297; Viscosity/(Pa•s): 0.742×, 1.5×; Thermal conductivity (W/m•k): 0.624, 0.0279; Prandtl number: 4.96, 1.773.
Equipment structural parameters: Type – Floating head type; Number of shell sides: 1; Inner diameter of shell/mm: 1400; Number of units: 1; Pipe diameter/mm: Φ25×2.5; Pipe center distance/mm: 32; Pipe length/mm: 7000; Pipe arrangement: △; Number of pipes: 1224; Number of baffle plates: 14; Heat transfer area/㎡: 673; Baffle plate spacing/mm: 450; Number of tube sides: 2; Material: Carbon steel.
Main calculation results: Tube side, Shell side; Flow velocity/(m/s): 1.306, 4.9; Surface heat transfer coefficient/: 5887, 925.5; Fouling thermal resistance/(㎡•k/W): 0.0006, 0.0004; Pressure loss/MPa: 0.04325, 0.119; Heat transfer rate/KW: 10417; Heat transfer temperature difference/K: 48.3; Heat transfer coefficient/: 400; Safety margin/%: 24.9%.
VII. References: 1. Liu Jiwen (ed.), Introduction to Petrochemical Equipment and Manufacturing, Harbin ； Harbin Shipbuilding Engineering Institute Press, 1989. 2. GB4557.1–84: Sheet sizes and formats for mechanical drawings 3. GB150–98: Steel pressure vessels 4. Welding Handbook, Volume 3: Welded structures, compiled by the Welding Society of the Mechanical Engineering Society, Beijing ； Mechanical Industry Press, 1992. 5. Du Lichen et al., Handbook of Engineering Welding, Beijing: Atomic Energy Publishing House, 1980. 6. Sixth Research Institute of the Ministry of Chemical Industry, Requirements for Technical Drawings of Chemical Equipment, Chemical Industry Equipment Design Center, 1991.

I won’t go into details; I suggest you borrow a book on course design for Basic Principles of Chemical Engineering. I also worked on heat exchangers at that time, mainly referring to the book \"Course Design for Chemical Unit Processes and Equipment\" written by Kuang Guozhu from Dalian University of Technology, which provides very detailed information.

Doing a graduation project on heat exchangers? I think there are more reference books than usual, right? I think I can just flip through the book by myself! You must be an expert in this area. Young man, what is learned from books is superficial; to truly understand something, one must put it into practice!

It is necessary to know the inlet and outlet temperatures and flow rates on the cold side, as well as those on the hot side. The heat exchange area can be calculated and the approved heat exchange area can be determined using the above parameters. Take some time to study the principles of chemical engineering when you have a chance!

Now that I know the amount of work involved, I’m learning *other programs.

This should be part of the course assignment for Principles of Chemical Engineering; you can refer to textbooks on Principles of Chemical Engineering or design manuals, as the information is available there. Just follow the steps one by one