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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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 :
2. 2
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. START Equipment selection Required duty Experimental data
analysis Experimental data End [ general application ] 4
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. 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. 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
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
34. the relation which defines the known F where the washing
time and total cycle time: 34
35. the cumulative volume of liquid the mass of solute in the
cake: 35
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
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
39. the cake saturation: the reduced saturation 39
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
41. the actual deliquoring time (td): the total cycle time: the
cumulative volume of liquid: 41
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
43. Noting that Pa = P 43
44. 44
45. the mass of liquid in the cakes: the mass of solute in the
cakes: 45
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