Equipment Costing Chapter 22 p 558 597 CH

Equipment Costing Chapter 22 (p 558 -597) CH EN 4253 Terry A. Ring

6/10 th scale up/down Factor • Used for scaling the total capital cost for a chemical plant of a different size • Cost 2/Cost 1 = (Capacity 2/Capacity 1)0. 6 • Accounts for economy-of-scale

Accounting for Inflation • Cost to purchase = Base Cost*(I/Ibase) – Base Cost, CB, = Historical price at Ibase – I is a Cost Index at present time • Chemical Engineering, CE, Plant Cost Index • Marshall and Swift (MS) Equipment Cost Index • Nelson-Farrar (NF) Refinery Construction Cost Index • Engineering News-Record (ENR) Construction Cost Index – Cp(I) = Cp(Ibase)*(I/Ibase) – Cp(Ibase)=FT*Fm*Cbase(Ibase)

Cost Estimate Methods • Order of Magnitude Estimate – Method of Hill • Marshall Swift for I/Ibase • Six Tenths Rule for Production Capacity – CTCI-2 (I)=CTCI-1 (Ibase)*(I/Ibase)* (Capacity 2/Capacity 1)0. 6 • Study Estimate (± 35%) – Method of Lang • CTCI=1. 05*f. L-TCI ∑ (Ii/Ibase-i) Cp-i • Lang factors for different types of Plants – Solids -3. 10, Solids&Fluids 3. 62, Fluids 4. 73 • Sum over all major equipment • Preliminary Estimate (± 20%) – Method of Guthrie – Bare module cost, CBM= Cp-base(I/Ibase)[FBM+(Fd. Fp. Fm-1)] • d= design factor, p = pressure factor, m =materials factor – CTCI= ∑ CBM_i • Quote Estimate

Purchase Costs for Equipment • Size Factor, S, depends on type of equipment • Cp(Ibase)=A*(S)b • Cp(Ibase)=exp(Ao+A 1[ln. S]+A 2[ln. S]2+…) • Your book gives 2006 base costs • Ibase = 500 (2006) average

Pumps & Electric Motors • Pump Types (Centrifugal, Gear, Plunger) – Centrifugal Pump • • • Size factor, S=Q(Head)0. 5 Base Cost, CB=exp(9. 2951 - 0. 6019[ln(S)] +0. 0519[ln(S)]2) Cp=FTFMat. CB Fm materials factor see Table 22. 21 FT pump type factor see Table 22. 20 Other types of pumps have different CB formulas – Electric Motor to drive pump • Size Factor=Power consumption, PC=PT/ηp/ηM=PB/ηM=QHρ/(33, 000ηpηM) • Q= flow rate, H = head, ρ = density • Efficiencies (pump and motor) are a function of flow rate and break horsepower (power without any losses), respectively • CB=exp{5. 4866+0. 013141[ln(PC)]+0. 053255 [ln(PC)]2 +0. 028628 [ln(PC)]30. 0035549[ln(PC)]4} • Cp=FTCB • FT= motor types factor see Table 22. 22 • ηM=~90% – Installation, etc, FBM=3. 3 – CBM=FBM*∑CP

Fans • Fan – – – Sizing factor is the volumetric flow rate, Q Different CB formula for different types of fans CP=FHFM CB FH Head factor see Table 22. 24 FM material of construction factor • Fiberglass • Stainless steel • Nickel Alloy 1. 8 2. 5 5. 0 • Motor size by PC=QHt(in. water)/(6, 350 ηFηM) • ηM =~90%, FBM = 2. 15 • CBM=FBM*∑CP

Blowers • Sizing factor is the power consumption, PC • Centrifugal (turbo) Blower CB=exp{6. 6547+0. 7900[ln(Pc)]} • CP=Fm-fans. CB • Motor – Motor size by PC=QHt(in. water)/(6, 350 ηFηM) – ηM =90% , FBM = 2. 15 • CBM=FBM*∑CP

Compressors • Compressor types – Centrifugal, CB=exp{7. 2223+0. 80[ln(PC)]} – Reciprocating, CB=exp{7. 6084+0. 80[ln(PC)]} – Screw, CB=exp{7. 7661+0. 7243[ln(PC)]} • Size factor is the power consumed, PC=PB/ηC • CP=FDrive. FMat. CB • • FDrive =1 (electric motor), 1. 15 (steam), 1. 25 (gas turbine) FMat = 1. 0 Carbon steel, 2. 5 SS, 5. 0 Nickel Alloy CBM=FBM*∑CP FBM = 2. 15

Heat Exchangers • Types of Heat exchangers – – – Floating, CB=exp{11. 667 -0. 8709[ln(A)]+0. 09005[ln(A)]2} Fixed Head, CB=exp{11. 0545 -0. 9228[ln(A)]+0. 09861[ln(A)]2} U-tube, CB=exp{11. 147 -0. 9186[ln(A)]+0. 09790[ln(A)]2} Kettle, CB=exp{11. 967 -0. 8709[ln(A)]+0. 09005[ln(A)]2} Thermosiphon, CB= Double pipe, CB=exp{7. 1248 -0. 16[ln(A)]} • Size Factor is HX area, A • CP=Fp. FMat. FLCB • Pressure Factor, Fp= 0. 9803+0. 018(P(psig)/100)+0. 0017(P(psig)/100)2 – Not for double pipe • Materials Factor, Fmat=a+(A/100)b, a & b from Table 22. 25 – a≥ 1. 0 note error in first row of Table 22. 5 • • Tube Length Factor FL= 1. 25 for 8 ft, 1. 0 for 20 ft. on a sliding scale CBM = FBM*CP, FBM=3. 17 (S&T), 1. 80 (DP), 2. 17 (Fin/Fan)

Fired Heaters • Size Factor is the heat duty, Q • CB=exp{0. 08505+0. 766[ln(Q)]} • CP=FPFMat. CB • FP=0. 986 -0. 0035(P(psig)500)+0. 0175(P/500)2 • Fmat=1. 4 Cr-Mo alloy steel, 1. 7 for stainless steel • CBM = FBM*CP, FBM=2. 19

Pressure Vessels • Storage Tanks • Distillation Towers – Tray – Packed • Absorber Towers • Stripping Towers

Pressure Vessels • Sizing Factor is the weight of steel, W • Horizontal Vessels, 1, 000<W<920, 00 lb CB=exp{8. 717 -0. 2330[ln(W)]+0. 4333[ln(W)]2} • Vertical Vessels, 4, 200<W<1, 000, 00 lb CB=exp{6. 775 -0. 18255[ln(W)]+0. 02297[ln(W)]2} • Add Platform Costs, – Horizontal, 3<Di<12 ft • CPL=1580(Di)0. 20294 – Vertical, 3<Di<21 ft • CPL=258. 1(Di)0. 7396(L)0. 70684 • Weight, W=π(Di+ts)(L+0. 8 Di)tsρs • C=FMCB+CPL • FM= materials factor see Table 22. 26 – Installation, etc, FBM=4. 16 (V), 3. 05 (H) – CBM=FBM*∑CP

Hoop Stress Calc for thickness, ts • Design Pressure is function of operating pressure, Po – For Po> 1, 000 psig use Pd=1. 1 Po – For Po< 1, 000 psig but not for vacuum • • Pd=exp{0. 60608+0. 91615[ln(Po)]+0. 0015655[ln(Po)]2} Thickness (Hoop Stress Calculation) ts= Pd. Di/(2 SE-1. 2 Pd) S = max allowable stress for steel is f(T) E = weld efficiency (fraction) Minimum wall thickness for given diameters May add extra thickness for wind stresses, corrosion Different calculation for vacuum vessels – Also account for leakage when vacuum vessel is used

Distillation Towers • Pressure vessel with plates or packing and additional nozzles and manholes • Tray Cost CT=NTFNTFTTFTMCBT • NT= no. trays • FNT= 1 for NT>20 otherwise FNT=2. 25/(1. 0414 NT) • FTT = tray type, 1. 0 sieve, 1. 87 bubble cap • FTM= Materials, f(D) – Carbon Steel FTM=1. 0 – 316 SS FTM=1. 401+0. 0788 Di • Installation, etc, FBM=4. 16 – CBM=FBM*∑CP

Packed Distillation Column • Pressure vessel with platforms plus packing • Packing Cost basis is volume of packing, VP • C=Vp. CPK+CDR • CPK= is installed cost per unit volume • Distributors cost, CDR

Absorbers/Strippers • Pressure Vessel plus platforms and packing • Separate costs for blowers • Separate costs for motors

Other process equipment • Different sizing factors • Different basis cost equations • Same methods used for cost calculation

Other Process Equipment • Various Size Factors • Table 22. 32