Section-3-Machine-Design-of-Typical-Chemical-Vessels[典型的化工容器第三节机械设计](98)课件.ppt

1、4.U Tube Type Heat Exchanger2.Float Head Heat Exchanger3.Stuffing Box Heat Exchanger1.Fixed Tube Sheet Type Heat ExchangerFixed Tube Sheet Type Heat Exchanger接 管 法 兰管 箱容 器 法 兰排 气 管膨 胀 节管 板拉 杆定 距 管折 流 板换 热 管壳 程 接 管支 座排 污 口管 程 接 管Nozzle Flange Pipe Connecting F. 接管法兰接管法兰Vessel Flange 容器法兰容器法兰Tube Shee

2、t Plate 管板管板(Air) Vent Nozzle 排气管排气管Expansion Joint 膨胀节膨胀节Shell Nozzle 壳程接管壳程接管Tie Rod 拉杆拉杆(Pipe) Spacer 定距管定距管Header Channel (head) 管箱管箱Baffle 折流板折流板Heat Exchange Tube 换热管换热管Inner Pipe Nozzle 管程接管管程接管Drain (Outlet) 排污口排污口Support 支座支座3.Strength Designi. Confirming the strength dimension (wall thickn

3、ess S) of units like shell, heads, etc. ii. Opening reinforcement computation4.Tube Sheet Design5.Calculation of Thermal temperature (difference) Stress6.Calculation of Tube-to-Tubesheet Joint Load pulling-out force of tubeMain PartsCylinder (Shell)HeatsTube Sheet (Plate)Tube (Pipe) BundleBaffle, Ti

4、e Rod, (Pipe) Spacer Pass Partition (Plate)、16Mn、15MnV1Cr18Ni9Ti 3.Connection of Tube and Tube Sheeti.Expansion Joint胀接胀接Before Expansion JointAfter Expansion Jointii. Welding Soldered Joint焊接焊接iii. Expanded and Welded Joint胀焊结合胀焊结合Advantages:(1)Strengthening the Resistance to Fatigue at the joint(2

5、)Eliminating the Stress Corrosion (应力腐蚀应力腐蚀) and Gap Corrosion (间隙腐蚀间隙腐蚀), then raising the lifetimeMethodology:(1)Welding before expanding (先焊后胀先焊后胀)(2)Expanding before welding (先胀后焊先胀后焊) 4.Structure of tube sheet and the connection of it with shell Depending on types of heat exchangerTow TypesNon-

6、movable (Fixed) Tube Sheet used to fix the Shell-and Tube Heat Exchanger Detachable (Non-fixed) Tube Sheet used in Float Heat, Stuffing Box, U Type Heat Exchangeri. Fixed Tube Sheet used in Fixed Tube Sheet Type Heat Exchanger ii. Non-fixed Tube Sheet the connecting structure of Float Head, U Type a

7、nd Stuffing Box Heat Exchanger 5.The Sealing between Tube Sheet and Header Taking the Double Tube Side (Pass) as the example:Partition of Channel Head:Structure of Channel Head:6.Structure of Shell Side (Pass)Main Units in Shell Pass Baffle Base Plate-支承板支承板 By-pass Baffles (Sealing Strip)-旁路挡板旁路挡板

8、Impingement Plate (Baffle)-防冲板防冲板 etc.i.Baffles and Base Plate折流板折流板 支撑板支撑板Function: (1)Increasing the flow velocity of fluid in shell pass and verifying the flow direction Elevating the Heat Transfer Efficiency(2)Bearing the heat exchange tubesTypes:Arcuate, Disc and Doughnut Type, Fan Shaped.Arcua

9、teDisc and Doughnut TypeFan Shapedii. By-pass Baffles旁路挡板旁路挡板 While there has clearance large enough between shell and tube bundle, we set the plates along the longitudinal direction and force the fluid across the tube bundles in order to avoid the fluid flow into the shortcut.iii. Function of Impin

10、gement Plate防冲板防冲板 Preventing the fast flowing media rushing (冲刷冲刷) the tube bundles at the porch of shell passiv. For Steam Inlet Tube入口管入口管 Making as Bugle Type to decrease the flow velocity and fulfil the buffering functionConditions:(1)Rigid connection between tube bundle and shell(2)Thermal T.D

11、. Stress occurs between tube and shellii. Calculation of Thermal T.D. Stress热应力计算热应力计算Assumption:Cold fluid flowing in shell pass, wall T of shell is tsHot fluid flowing in tube pass, wall T of tube is ttIn the course of installation tt = ts = toIn the course of operation(1)If the tube and shell can

12、 elongate freely s = s（ ts to）L t = t（ tt to）L(2)If the elongation is limited rigidly, both of them only elongate at the same length difference L s t At this moment:Tube is compressed by compressive force Fcomp. Compressive Stress (压应力压应力) t occurs on the tube wallShell is pulled by tensile force Ft

13、ensile Tensile Stress (拉应力拉应力) S occurs on the shell wallThis kind of stress caused by temperature difference is called Temperature Difference Stress or Thermal Stress.Calculation of Thermal Temperature Difference Stress:If the deformation caused by temperature difference is among the range of elast

14、icity, according to the Hooks Law:(1) EAFL(2) ttttAEFL(3) ssssAEFL(4) )(ottttt (5) )( ossstt And Compressive Length of tube:Stretched Length of shell:Equ. (2) + Equ. (3), and putting Equ. (4) and (5) into it, working up:(6) 11)()(ssttossottAEAEttttF(7) ttAF(8) ssAF Thermal Stress on tube wall Therma

15、l Stress on shell wallIn these equations:At Total sectional area of heat exchange tubes, mm2As Area of intersect surface on shell wall, mm2Et 、Es Materials Modulus of Elasticity of tube and shell respectively, MPa2.Calculation of Tube-to-Tubesheet Joint Load Pulling-out ForcePulling-out Force q is t

16、he force that is endured by the surface of per square meter expanding perimeter of tubes, Mpai. Pulling-out Force q p caused by pressure of medialdfpqopofAreaActing perimeter expanding media of force In this equation:P Design Pressure, choosing the larger value between pressure in tube pass Pt and p

17、ressure in shell pass PS, MPalPtPSdo Outside Diameter of tube, mml Expanding Length of tube, mmf Area among per four tubes, mm2fIn-line Triangular Pitch(三角形排列三角形排列)afSquare Pitch ArrangementIn-line Square Pitch正方形排列正方形排列a22224866. 0460sinoodadaf224odafIn-line Triangular PitchIn-line Square Pitchii.

18、Pulling-out Force qt caused by Thermal Stress t Thermal Stress inside tubes, Mpa at Area of intersect surface of tube wall per tube, mm2ldaqotttAreaStressThermal Perimeter Expandingof ldddldddoiotoiot 4 4 2222iii. Superposition of qp and qt Total pulling-out force equal to their algebra sum: q = qp

19、+ qtiv. Allowable Pulling-out Force q q depends on the joint type of expansion joint between tube and tube sheet.Expanding Structure Type of tube and tube sheetq MPaNon-flanged pipe end and non-notched tube sheet holes 2.0Flanged pipe end and notched tube sheet holes4.0v. Strength Conditions of Expa

20、ndingTo assure the expanding joint undamaged and locked, should satisfying: q Pulling-out Force of tubes, MPaq Allowable Pulling-out Force, MPa3.Thermal Stress Compensation热应力补偿热应力补偿Compensation Measures:i. Decreasing the temperature difference between tube and shell wall(1)Letting the fluid with la

21、rger Film Coefficient of heat transfer flow across the shell pass(2)When shell wall T tS = Se Assuming the effective thickness of skirt support shell is Ses Ses = 6mm iv. Calculating the axial stress under various loads of tower(1)Axial stress 1 caused by media pressure(2)Axial stress 2 caused by we

22、ight load(3)Axial stress 3 caused by bending momentv. Calculating the combined axial stress of tower under the combined effect of multiplicate loads should satisfy: Condition for strength Condition for stability Else the thickness must be reassumed until satisfying all the verification conditions. (

23、 and ( pmaxlecomb.tensi）tKp.iv. Calculating the base ring and anchor bolt according to the loads under the above-mentioned work conditions.5.Verification of stress in hydrostatic pressure test (水压试验水压试验)i. Testing pressuretTPp25. 1ii. Calculating all stresses(1)Hoop stress caused by testing pressure

24、(2)Axial stress caused by testing pressureieieiTTSSDP.2)(P)-static liquid(ieieiTSSDP.14)(3)Axial stress caused by gravity(4)Axial stress caused by wind bending moment and eccentric bending momentieiiiSDgm.max2 ieieiiwSDMM.2343 . 0iii. Strength condition in hydrostatic pressure test(1)Hoop stress(2)M

25、aximum combined axial tensile stress(3)Maximum combined axial compressive stresssT9 .0sK9 . 0321maxlecomb.tensicr32max.压组min 9 . 0KBKscr7.3 Design of Skirt Support 1. Structure of skirt supportExhaust opening 排气孔排气孔Access opening of outgoing tube 引出管通孔引出管通孔Bed body 座体座体Manhole 人孔人孔Anchor Bolt 地脚螺栓地脚

26、螺栓Bolt Base 螺栓座螺栓座Base ring 基础环基础环Bed 基础基础2.Design of skirt supporti. Enactment an effective thickness Ses according to the tower bodyii. Verifying the strength and stability of dangerous sections on skirt supportDangerous sections:(1)Basis section (基底截面基底截面)(0-0)(2)manhole section (人孔截面人孔截面) (1-1)Dangerous Sections is illustrated like the picture: