化工机械设备课程设计说明书

Fundamental Chemical Process Equipment Course DesignThe Mechanical Design of a Distillation ColumnDesign Date : Dec 25th 2013Major :Chemical Engineering (English Minor),1001Name :Wang HaotongStudent ID : 201048511Tutor :Professor Yu Jianliang, Zhou YihuiContentPreface31.Introduction31.Introduction3Design Conditions4Calculation of Column Body and Head Thickness5Calculation of Column Mass Loads5Calculation of Wind Load and Wind Bending Moment7Calculation of Seismic Bending Moment9Axial Stress Caused by Loads10Strength and Stability Check of Dangerous Section of Column Body and Skirt11Stress Check in Hydrostatic Pressure Test and Installation13Design of Base Ring14Calculation of Anchor Bolt15Calculation of reinforcement for openings16Nomenclature18Reference19PrefaceChemical industry is a fundamental industry. There are many different types of chemical equipment to meet the various needs of chemical production. The operating conditions of chemical equipment are relatively complicated. But in practice, columns, heat exchangers, pumps and pipes are of the most importance. In the following , we need to design a plate distillation column , using the parameters in Chemical Principle Course Design we have already calculated. The operational diversity makes the selection of appropriate materials for chemical equipment more complicated, which is an important part in designing of chemical equipment. This case is based on the certain process and environment conditions, such as pressure, wind load, seismic load as well as mass load . And after the basic steps are taken, we need to test the stress for every part of the column, which involves the vessel and skirt. As the distillation column is assumed to be stalled in Dalian, the environmental conditions of Dalian are chosen and according to the working process. Some of the details have benn changed to fit the actual process. 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. Distillation columns are made up of several components, each of which is used either to transfer heat energy or enhance material transfer 1-2. The acceptance of present computer-aided design (CAD) systems is closely connected with their abilities to support problem solving in the fields of computer-aided design and process planning. Today, comprehensive and general solutions still do not exist and are unlikely to be available in the near future. So, besides geometrical capacity, one of the most important aspects to be considered is probably the quality of the human-computer interface. Fulfilling the requirements of this interface is one of the most problematic tasks in planning future CAD systems. These problems can be solved only by discussing and trying out new and probably unusual methods. In this vein, a system concept will be presented that allows solid model design by sketched views and related dimensions on a tablet. The solids will be created automatically using two-dimensional to three-dimensional reconstruction techniques. The introduced system concepts are partially realized in a working system. Diverse components such as dimensioning are still under development at present. Generation of qualitative described solids by sketch input is already possible today 3-6. Continuous columns process a continuous feed stream. No interruptions occur unless there is a problem with the column or surrounding process units. They are capable of handling high throughputs. A continuous column operates under steady conditions where the composition at a given location does not change over time. The composition only depends upon the position in the column and so additional product steams can be easily tapped at different heights and each tray will have a different composition of compounds 7.1. Introduction1.1 General requirements. The design of pressure vessel should meet the following general requirements1. Meet strength requirement .The required strength is indispensable to guarantee the vessel safe operation2. Meet rigidity requirement. A vessel and its internal parts should have enough rigidity to prevent over deformation in fabrication and transportation.3. Meet stability requirement .Stability means the capability of vessel to stabilize geometry with external pressure load. External pressure load should have enough stability to prevent bucking.4. Durability. 5. Seal. 6. Material and fabrication.7. Easy operation and transportation.8. Technical and economy evaluation.1.2 The basic contents for mechanical design of columnIn this case, all the parameters of the column, including the thickness, mass, wind bending moment, seismic bending moment, the hydrostatic pressure test and installation are calculated. AutoCAD is used as the basic tool to the design the equipment. The script has drawn in full proportion with the use of AutoCAD. The structural design includes plate ,manhole ,the bottom and the top of the tower. In addition, the size of pipes, hanging pillars and insulation structures are also considered.Column wall thickness calculation and strength check include the hydrostatic test stress verification, the opening reinforcement calculation, determination of the dangerous sections, shell weight, horizontal bending moment wind, seismic moment calculation and eccentric bending moment calculation, tests of combination of axial tensile, compressive strength and stability calculation. Skirt structure design and strength check include basic ring, the skirt body, skirt, anchor bolt and weld design and check. In the following, we will analyze all these problems2.Column Design 2.1 Design Conditions(1) Apply the safety valve, then calculating pressure is (2)Design conditions of a column are shown as follows.a. Internal diameter of the column body Di=1200mm, height of the column is approximately H=45000mm.b. Calculating pressure pc=2.90 MPa, design temperature t=-19C.c. Installation location: reference wind pressure qo=500 N/m2, seismic-resistance intensity is 7 degrees, type of site soil: , design seismic group: 2, design basic seismic acceleration is 0.4g.d. Valve trays are installed in the column, number of trays N=76, liquid height on each tray , density of medium 404kg/m3.e. Manhole is set about every 5 meters along the column vertically, total number of manholes is 5, semicircular platform is installed with corresponding manhole, width of the platform mm, height is 1000 mm.f. Thickness of insulation mm, density of insulation material kg/m3.g. A reboiler is hung between the column body and the skirt, its operation mass kg, eccentricity mm.h. Material of column and head is Q345R with , .i. Material of skirt is Q235-B.j. Column body and skirt is butt welded, welding coefficient .k. Additional thickness of column body and head mm, additional thickness of the skirt mm.2.2Calculation of Column Body and Head Thickness(1)Calculation of column body thickness：Consider the additional value of thicknessmm, after rounding, .(2)Calculation of head thickness：Use standard ellipsoidalConsider the additional value of thicknessmm, after rounding, .2.3Calculation of Column Mass Loads2.3.1 Cylinder, head, skirt mass(1) Cylinder mass: The total height of the cylinder:(2) Head mass:Consulting GB/T25198-2010, mass of cylinder with the size of is (3)Skirt Where ,， 2.3.2Mass of internal parts 2.3.3Mass of insulationwhere is mass of head insulation. 2.3.4Mass of platform and ladder Note: Consulting Table 8.1 in Fundamental Chemical Process Equipment, mass of the platform: kg/m2; mass of cage ladder: kg/m; total height of cage ladder: m; number of ladders: n=Mass of materials in operation Note: Material density; head volume; depth of the cylinder; tray number; height of liquid on the tray.2.3.6 Mass of accessories maBy experience, 2.3.7 Mass in hydrostatic pressure test mw where.2.5.8 Summary of mass loadsAs shown in Table 1, the column is divided into 6 sections, mass loads of each section is calculated as following (approximately)Table 1 Summary of mass loadsSection01122334455667TotalHeight of section/mm100040008000800080008000800045000Number of manhole and platform00111115Number of trays00161515151576 33691813211321132113211321119605 _117611021102110211025587 042.96100110011001100110045052 40160813.8196813.8196813.8196813.82813.824268 _7865715355355355353499 842458038038038038034901 _2559048904890489048893545380 _14002600_4000 4252261610176746674667466747046912Minimum mass of each section /kg42511829866360496049604960529389449Operation mass of the whole column/kgMinimum mass of whole column/kgMass in hydrostatic pressure test2.4 Calculation of Wind Load and Wind Bending Moment2.4.1 Calculation of Wind Load(1) is vibration period fundamental mode, for the circular column with equal diameterand thickness:(2)Calculate wind vibration coefficient Where is vibration mode coefficient, consulting consulting Table 8.8 in book, is pulsating amplifying coefficient, consulting Table 8.6, is pulsating effect coefficient, check Toable 8.7. The result is shown in Table 2.Table 2.Sec.123456714888882.952.952.952.952.952.952.950.720.720.720.790.790.790.850.020.030.060.230.470.601.000.800.800.921.181.351.481.601.051.071.141.441.832.002.57(3)Effective diameter De3 is effective diameter of column, which is bigger value of a,bWhere ,The result is shown in Table 3.Table 3Sec.1234567 1000400080008000800080008000K3/mm400400400400400400400K4/mm0.000.00124.84124.84124.84124.84124.84Dei/mm196119612085.842085.842085.842085.842085.84(4) Calculation of the wind load Where K1 is shape coefficient, for cylindrical container, K1=0.7;q0 is reference wind pressure at 10m, ; is wind pressure height coefficient, consulting Table 8.5 in book; li is length of the calculation segment. The result is shown in Table 4.Table 4Sec.1234567 0.7 1.71.692.172.58500500500500500500500 0.8000.8001.021.561000400080008000800080008000196119612085.842085.842085.842085.842085.84 933.433733.79145.711730.413341.418907.224.2Calculation of wind bending moment(1)Section 0-0(2)Section 1-1(3)Section 2-22.5 Calculation of Seismic Bending Moment2.5.1Illustration of seismic bending moment calculation The fluctuating amplifying coefficient of the fundamental mode Attenuation index =2.72s Total height of column H =45000mOperating mass Gravity acceleration Earthquake affecting coefficient Consulting Table 8.2 and Table 8.3 in Fundamental Chemical Process Equipment( Seismic-resistance intensity is 7) 2.5.2 Calculation of seismic bending momentSection 0-0Section 1-1Section 2-22.6 Calculation of eccentric bending momentum 2.7 Axial Stress Caused by LoadsAxial stress caused by loads1.Axial tensile stress caused by calculated pressure(MPa)where (mm).2. Axial tensile stress caused by operation massSection 0-0 (MPa)Take the skirt thicknessmm; effective thickness (mm);.Section 1-1(MPa)where(kg); is the section area of the manhole ,consulting relative code,mm2.Section 2-2(MPa)where (kg);.3. Axial stress caused by maximum bending moment Section 0-0(MPa)where Section 1-1(MPa)where is the section modulus in bending of the manhole cross-section ,consulting relative code,mm3.Section 2-2(MPa)where Strength and Stability Check of Dangerous Section of Column Body and SkirtStrength and stability check of dangerous section of column body and skirt1. The maximum combined axial tensile stress check of the column bodySection 2-2The maximum combined axial tensile stress of the column locates in section 2-2, where .Requirements are satisfied.2. Stability check of column body and skirtSection 2-2The maximum combined axial compressive stress in section 2-2Requirements are satisfied.where Consulting Fig. 5-9 (16MnR, 200C) Section 1-1The maximum combined axial compressive stress in section 1-1Requirements are satisfied.where Consulting Fig. 5-9 (16MnR, 200C) Section 0-0The maximum combined axial compressive stress in section 0-0Requirements are satisfied.where Summary of strength and stability checkItemsDangerous section0-01-12-2Effective thickness of skirt and column body, 181818Operation mass abovethe cross-section 663146528160232Calculation sectionarea Calculation section modulus in bending Maximum bending moment2.61092.511091.14109Maximum allowable axialtensile stress, 173.4Maximum allowable compressive tensile stress /MPaKB205.2205.2205.2204204204Axial tensile stress caused by calculation pressure/MPa0064.7Axial compressive stress caused by the operation mass/MPa7.187.336.52Axial stress caused bymaximum bending moment/MPa71.9667.759Maximum combined axialtensile stress/MPa117.2Maximum combined axialcompressive stress/MPa79.27565.6Strength and stability checkStrengthRequirements satisfiedStabilityRequirements satisfiedRequirements satisfiedRequirements satisfiedStress Check in Hydrostatic Pressure Test and InstallationStress caused by various loads in hydrostatic pressure test1. Hoop stress caused by test pressure and static pressure of liquid headHydrostatic pressure2. Axial tensile stress caused by test pressure3. Axial compressive stress caused by the maximum mass4. Axial stress caused by bending momentStress check in hydrostatic pressure test1. Hoop stress check of the cylinder Requirements are satisfied.2. Check of the maximum combined axial tensile stressRequirements are satisfied.3. Check of the maximum combined axial compressive stressRequirements are satisfied.Design of Base RingDesign of base ring1.Size of the base ringTake 2. Stress check of the base ringwhere, (1) (2) Take the larger value .Use 250# concrete, consulting its allowable stress Requirements are satisfied.3. Thickness of the base ringAssume that the diameter of the bolt is M56, consulting Tab. 8-11, l=200mm, b/l=130/200=0.65, consulting Tab. 8-10Take the larger one, .Calculate the thickness of base ring with ribs:Take after rounding.Calculation of Anchor BoltCalculation of anchor bolt1. The maximum tensile stress that the anchor bolts withstand iswhereTake the larger value, 2. Pitch diameter of anchor bolts, take the number of anchor bolts The maximum of perimeter Pmax=The perimeter required Pr=Requirements are satisfied.Calculation of reinforcement for openings1. ParameterDi=800mm, C=2mm, The inner diameter of manhole Dim=800mmThe extended height of tube h1=h2=125mmSince the material of manhole and cylinder are both 16MnR, fr=12. Reinforcement and the judgment of reinforcing method (1). Judgment of reinforcingThe inner diameter of manhole Dim=800mm89mm, P2.5MPa, so reinforcement should be considered. The diameter of opening We can use equal-area method of reinforcement.(2). Calculation of reinforcementCalculation thickness of tubeEffective widthEffective height of the outside tubeEffective height of the inside tubeThe area needing reinforcementThe areas which can be used as reinforcementCompare and A, considering the weld area A3, the excess metal of the structure satisfies the requirement of reinforcement, the manhole does not need further reinforcement.Since the manholes at 1-1section bear the maximum stress, so here only considering the reinforcement of the two manholes.NomenclaturesignSignificance and unitsignSignificance and unitAprojected area of the platform，mm2Seismic bending moment of i-i section, NmmAbArea of base ring，mm2The maximum bending moment of i-i section, NmmAabCross area of 0-0 section，mm2Wind bending moment of i-i section, NmmAsmCross area of 1-1 section，mm2The maximum of the column, kgBFactor for axial compressive stress, MPaThe minimum of the column, kgbOutside radial width of base ring , mmm0Operating mass, kgCzStructure comprehensive effect coefficientm0i-iOperating mass above i-i section, kgDeiEffective diameter of calculation part, mpcCalculation pressure, MPaDiInner diameter of cylinder, mPihorizontal wind force of I part, NDibInner diameter of base ring, mq0Wind velocity pressure, N/m2DobOuter diameter of base ring, mSbThickness of base ring, mmDisInner diameter of skirt, mSeEffective thickness of cylinder, mmDoOuter diameter of cylinder, mSehEffective thickness of head, mmDosOuter diameter of skirt, mSesEffe