1. 1. 1 SAJJAD KHUDHUR ABBAS Chemical Engineering , Al-Muthanna University, Iraq Oil & Gas Safety and Health Professional OSHACADEMY Trainer of Trainers (TOT) - Canadian Center of Human Development Episode 5 :
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3. 3. There are many solid/liquid separation techniques which have established general application within the process industries The selection of appropriate equipment is thus a challenge to the design engineer and it is often difficult to identify the most appropriate separator without extensive previous knowledge of a similar separation problem 3
4. 4. START Equipment selection Required duty Experimental data analysis Experimental data End [ general application ] 4
5. 5. Methods of equipment selection Although there are a number of different approaches to equipment selection, the overall procedure can be summarized by the flowchart shown STARTSTART Initial duty specification for equipment Table 1 & 2 to determine whether equipment is suitable Sedimentation and filtration tests and data analysis End Solid Liquid Separation - Equipment Selection and Process Design - Steve Tarleton, Richard Wakeman (Elsevier, 2007) 5
6. 6. Table (1) Classification of equipment according to suitability for duty and slurry separation characteristics. Type of equipment Duty specification Separation characteristics Settling Filtering Rotary (vacuum) disc a, b or c E g or i A or B D or E G or H J or K Screen (sieve bend) a, b or (c) d or e f, g or h (B) or C E F or (G) I, J, K, or L Rotary (pressure) drum B E g, h or i A or B D or E G or (H) (J) or K 6
7. 7. Table 2 Relative performance characteristics of solid/liquid separation equipment. Performance indices Feed solid properties Type of equipment Solids product Dryness &state Washing Liquid Product quality Crystal breakage Particle Size (m) % by Mass solid in feed Single leaf (vacuum Nutsche) 6 C 8 7 8 1500 110 Rotary (pressure) drum 6 C 6 7 7 1100 530+ High shear crossflow (Membrane filters) 2 S 4 6 4 0.120 1 and Lw < 10 cm then equation apply : The dispersion number is calculated from equation : The mass of solids in the cakes remains constant throughout washing and is equal to the value at the end of compression deliquoring (Ms = 4527 kg) also remains the same as the density of filtrate and wash are equal (Ml 3920 kg). 32
8. 33. As the ultimate fractional solute recovery (Fe) is known, intermediate values of F are determined by choosing a value between F =0 and F = 0.97 Alternatively, as shown below, the curvefit coefficients for the plots of dimensionless solute concentration ( ) vs. W, from which below Figure can be used. Referring to Appendix B, values of * are evaluated at a chosen number of wash ratios for both Dn =50 and Dn =100 where 33
9. 34. the relation which defines the known F where the washing time and total cycle time: 34
10. 35. the cumulative volume of liquid the mass of solute in the cake: 35
11. 36. F (-) W (-) tw (s) tT (s) VT (m3) Msol (kg) 0 0 0 2836 47.32 117.8 0.097 0.097 22 2858 47.70 106.4 0.194 0.19 44 2880 48.08 95.0 0.291 0.29 66 2902 48.46 83.5 0.388 0.39 88 2924 48.84 72.1 0.485 0.49 109 2945 49.22 60.7 0.582 0.58 131 2967 49.60 49.3 0.679 0.68 153 2989 49.99 37.8 0.776 0.78 176 3012 50.39 26.4 0.873 0.90 203 3039 50.85 15.0 0.970 1.08 243 3079 51.56 3.53 Data sequences for the washing phase of a diaphragm press cycle. 36
12. 37. The cake moisture content at the end of washing is the same as at the end of consolidation (i.e. Me 46.41%). 37
13. 38. 4 - Gas deliquoring phase The gas deliquoring phase is performed at a constant pressure of 400 kPa and it is required to reduce the cake moisture content to 25%. the active filter area is Ad =Af/2 =150 m2. The mass of solids in the cakes remains constant throughout gas deliquoring and equal to the value at the end of washing (Ms =4527 kg). As the moisture content at the end of deliquoring is specified, intermediate values of cake moisture are chosen between M =46.41% and M =25%. 38
14. 39. the cake saturation: the reduced saturation 39
15. 40. The reduced saturation of a filter cake (SR) as a function of a dimensionless deliquoring time (8) during deliquoring using vacuum or pressure applied in a gas phase. For details see Wakeman and Tarleton (2005a). The dimensionless deliquoring time (8) at the known SR is read directly from the design chart. 40
16. 41. the actual deliquoring time (td): the total cycle time: the cumulative volume of liquid: 41
17. 42. The dimensionless air flow rate through a filter cake (u*) during deliquoring using vacuum or pressure applied in a gas phase as a function of the dimensionless deliquoring time (8) and pressure p*. For details see Wakeman and Tarleton (2005a). 42
18. 43. Noting that Pa = P 43
19. 44. 44
20. 45. the mass of liquid in the cakes: the mass of solute in the cakes: 45
21. 46. M (%) S (-) td (s) tT (s) VT (m3) dVd/dtd (m3 s-1) ua|des (m3 m-2 s-1) Ml (kg) Msol (kg) 46.41 1.000 0 3079 51.56 3920 3.53 44.27 0.917 20 3099 51.89 0.0165 9.18 *10-6 3595 3.24 42.13 0.841 48 3127 52.19 0.0107 3.50 * 10-5 3295 2.97 39.99 0.769 84 3163 52.47 0.0064 7.88 * 10-5 3016 2.72 37.84 0.703 130 3209 52.73 0.0057 1.43 * 10-4 2756 2.49 35.70 0.641 188 3267 52.97 0.0041 2.30 * 10-4 2514 2.27 33.56 0.583 264 3343 53.20 0.0030 3.43 * 10-4 2287 2.06 31.42 0.529 365 3444 53.41 0.0021 4.78 * 10-4 2074 1.87 29.28 0.478 486 3565 53.61 0.0017 6.29 * 10-4 1874 1.69 27.14 0.430 896 3975 53.80 0.0005 9.98 * 10-4 1686 1.52 25.00 0.385 1742 4821 53.98 0.0002 1.42 * 10-3 1509 1.36 Data sequences for the gas deliquoring phase of a diaphragm press cycle. 46
22. 47. The overall results are summarized in this Table Parameter Value Filtration phase durations 0 1049 s and 1049 1418 s Compression deliquoring phase duration 1418 2836 s Washing phase duration 2836 3079 s Gas deliquoring phase duration 3079 4821 s Mass solids/cycle time 4527/4821 = 0.94 kg/s Total volume of liquids produced during cycle 54.0 m3 Ignores cake discharge time, cloth cleaning time, etc. 47
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24. 49. Outotec 1 516 2 512 3512 Filtration area m2 108 252 288 576 831-991 Filter volume m2 1.9 6.4 5,4 - 15,4 16,74-19,98 Filtration area/ chamber m2 3.6 9.6 13,4 Available frame sizes chambers 30-40-50-60-70 30-35-40-45-50- 55-60 62-74 Main dimensions Overall length mm 10 250 18 050 12250 19 300 19 450 Overall width mm 3 530 5 950 5 950 Overall height mm 4 240 3 870 3 870 Overall weight t 47 70 121 160 160-170 Installed power (hydraulics) kW 18.5 90 90 49
25. 50. References : 1.Coulson & Richardsons - Chemical Engineering 2.Solid Liquid Separation - Equipment Selection and Process Design - Steve Tarleton, Richard Wakeman (Elsevier, 2007) 3.Solid Liquid Separation - Scale-up of Industrial Equipment - Stephen Tarleton, Richard Wakeman (Elsevier, 2005) 4.Chemical-Process-Equipment-Selection-and-Design- by-Stanley-M.-Walas 50
26. 51. The End 51
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