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Published byEdward Cook Modified over 9 years ago
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PROPLEM DIFINITION Heat exchanger is a device used to transfer heat from a fluid (liquid or gas) to another fluid where the two fluids are physically separated. The Shell and Tube is the most common type of heat exchanger used in the process, petroleum, and chemical industries, it contains a number of parallel u-tubes inside a shell. Heat exchanger E-104 is shell and tube (horizontal) heat exchanger with change phase in the tube side by condensate the flow of this stream .In the shell side there are benzene but in the tube there are all water
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E-104 is operated in the shell in this condition .
Flow rate 4.95E+04 Kg/h Inlet Temperature ,T1 25 oC Outlet Temperature ,T2 165.1 Heat Capaxcity of inlet stream, Cpin 1.5196 KJ/kg°C Heat Capacity of outlet stream, Cpout 2.1685 KJ/kgoC Average Heat Capacity, Cpavg Mass Density of inlet stream , ρin 872.83 kg/m3 Mass Density of outlet stream , ρout 156.51 Average Mass Density, ρavg 514.67 Average Viscosity of stream, µavg 0.606 mNs/m2 Average Thermal conductivity, Kf 0.131 W/moC
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And the tube side is operated in these conditions
Flowrate 4.32E+00 Kg/s Average Heat Capacity, Cp 2.197 kJ/kgoC Average Mass Density, ρ 2.16 kg/m3 Average Viscosity of stream, µ 0.028 mNs/m2 Average Thermal conductivity of stream, Kf 0.068 W/moC inlet Temperature , t1 500 oC outlet Temperature, t2 151.8
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Materials of construction:
I checked in the materials compatibility program I found that with cresol the suitable materials is carbon steel because medium corrosion. The main functions of heat exchanger E-104 are to controlled the feed temperature of the distillation (T-100) , by increase it from 25to for the first and decrease it from 500C to 151.8C respectively
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Insulation: The insulation material for E-104 is mineral wool (10.0) according to this figure. Since the highest temperature is 500C .
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Calculations: Duty = 1.455*10^7KJ/HR
Overall coefficient: from table in the book 12.1 (4-4)
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Exchanger Type and Dimension
25 T2 165.1 t1 500 t2 151.8 ∆Tlm C 214.26 R - 0.4 S 0.733 Ft= 0.79 From Fig.12.20 ∆Tm 169.27 C
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Heat Transfer Area U= 500 W/m2.C ∆Tm 169.27 C Q= 3549.9 KW A= 41.94 m2
Assume Outler diameter (do) 50 mm Assume inside diameter (di) 46 Assume Length of tubes (L) 4.88 m tringual Pitch =1.25* dia. 57.5
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Assume 4 tube passes Cross sectional area Mm2 1661.9 Area/pass 415.47
Velocity m/s 87.9 Area of one tube m2 0.766 # of tubes 55 Tubes/Pass 14 From table 12.4 K1 0.175 n1 2.285
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Bundle and Shell Diameter
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Ds= 633mm Db= 576 mm bundle shell clearence 57
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Tube side Heat Transfer Coefficients
where jh is the heat transfer factor , assume that the viscosity of the fluid is the same as at the wall : (µ/µwall) = 1 (hi di / kf) = jh Re Pr0.33 * (µ/µwall)0.14 Re 3.07*10^5 Pr 9.22*!0^-2
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jh= 3.8E-03
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hi 1674W/m2.C
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Assume: lb = .05*Ds Shell side heat Transfer Coefficient: As 0.016007
35.5 mm us 1.667 m/s Assume: baffle cut is 25% , then get jh from figure 12.29 Re 5*10^4 jh 2.90E-03
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hs W/m2.C
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Overall Coefficient: Assume Kw = 45 W/m.C (for carbon stainless steel) (from figure 12.6)
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ho 1100.67 W/m^2.C hi 1674 hod 5000 1/Uo 0.002017 C.m2/W Uo 495.78
For fouling factor (hod) from table 12.25 ho W/m^2.C hi 1674 hod 5000 1/Uo C.m2/W Uo 495.78 W/C.m2
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Tube Side pressure drop
ΔPt = Np [ 8jf (L/di)(µ/µw)^(-m) +2.5 ] ρut²/2 Where ΔPt is tube side pressure drop Np is number of tube side passes Ut is tube side velocity L length of one tube Neglecting the viscosity correction term, (µ/µw) = 1 Pressure Drop Pa
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Thickness: t = (Pri/(SEJ-0.6P))+Cc Where: t = shell thickness (in)
P = Maximum allowable internal pressure (psig) ri = internal radius of shell before allowance corrosion is added (in) EJ = efficiency of joints S = working stress (psi) Cc = allowance for corrosion (in) ri = in P = 587.8 psi S = EJ = 0.85 Cc = 0.125 t = 0.773 in 19.6 mm
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Cost: Cost = 26500$ from matche program
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L-V Separator V-100
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Definition: The Vessel V-100 is used as liquid-vapor separator in which the feed to the vessel enters with 190 oC and 3410 KPa
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Metals: The Separator is made from carbon steel because of its ability to tolerate high temperature and its low cost compare to other metals. Also, from the material compatibility program we found that with our component suitable material is carbon material is carbon steel because there is no corrosion. The range of the temperature for the carbon steel is from -20 to 600 F and our Vessel operates at 190 oC which is within the range Flow rate: Stream Value Unit Feed 4573 Kgmol/hr Overhead 337.8 Bottoms 4235
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Insulation: The insulation material for our Vessel is Glass Fiber 4.0 according to this figure. Since the Vessel highest temperature is 190ºC
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Diameter: ρl ρv Parameter Value Unit L 3.496*10^5 kg/hr V 26810 689.91
kg/m3 ρv 22.599 Tin 190 oC P 34.1 Bar
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Thickness: The thickness is depending on many factors such as material type, operating temperature and the stress on the material. The following calculations will show the value of the thickness Parameter Value Unit Comment D 2.71 M Calculated P 494.7 Psi Pressure at the V-100 S 13700 Maximum allowable Stress of Carbon Steel Ej 0.85 Efficiency of joint Cc 0.125 In Allowance of corrosion
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Cost of insulation = (406000) (0.1) =40600$
Cost of Vessel Volum: V=A*t A=((2*r*3.14*H)+(4*3.14*r^2)) A= m2 V= m3 Weight: W=V*ρ ρ carbon steel=7900kg/m3 w= kg = ib Cost From Matche $ Cost of insulation = (406000) (0.1) =40600$ Cost = = $
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Distillation Column (T-102)
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Problem definition: Distillation is defined as a process in which a liquid or vapor mixture of two or more substances is separated into its component fractions of desired purity, by the application and removal of heat.
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Materials of construction:
I checked in the materials compatibility program I found that with cresol the suitable materials is Stainless steel 304 because medium corrosion.
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Thickness: The thickness is depending on many factors such as material type (in my case is stainless steel) and the stress on the material. T = 8.64mm
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Insulation: The insulation material for our Distillation is mineral wool (10.0) according to this figure. Since the highest temperature is 260.1C .
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Physical property : property Unit Top Bottom Mwt kgmole/kg 106.03
142.78 Vapor Flow kmol/h 3710.9 3092.1 Liquid Flow 618.49 3119.9 surface tension N/m ru liquid kg/m3 671.54 612.07 ru vapor 17.65 20.22
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calculate Plate pressure drop and real stage:
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Column Diameter calculation:
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K1 "Top" = 0.129, K1 "Bottom" = 0.108 Take Tray spacing = 0.9 m
Assume flooding= 85 % Assume Down comer area= 45 K1 "Top" = 0.129, K1 "Bottom" = 0.108
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Calculated liquid flow pattern
Single Pass Plate could be used
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Provisional Plate Design
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