Template:Solids PSD: Difference between revisions

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Revision as of 03:43, 27 July 2020

|- | colspan="3" font style="background: #ebebeb" |Solid Separation Requirements |- | valign="top" rowspan="7" | SolidMethod || valign="top" | Simple (no PSD) || The feed does not need size distribution for this method and the unit acts as a simple mass splitter. If the user chooses this mode then they must define the solids and liquids split from the unit. (This option is visible for the Screen 2 model only) |- | Partition Curve || The user inputs a Partition curve (fraction of feed solids per size interval reporting to the oversize) on the PartCrv(deck number) tab. The screen will use this curve, so the size distribution in the feed to the screen has no effect on products.
Note: A single partition curve is used for all the size distributions. |- | Whiten || The screen model will calculate the solids split using the Whiten method. The user must specify the d50 and alpha, a measure of the sharpness of separation. |- | Karra || The screen model will calculate the solids split using the Karra method. The user may specify either the d50 or the Screen area and Cut aperture. |- | Rosin-Rammler|| This method is based on a Rosin-Rammler type of function with the efficiency curve expression derived by Reid and Plitt. User must specify d50, sharpness of separation, maximum size allowed to undersize and minimum percent of solids reporting to oversize. |- | Lynch || This method is based on a Lynch type of function. User must specify d50, sharpness of separation (m), maximum size allowed to undersize and minimum percent of solids reporting to oversize. |- | DelVillar-Finch || This method is similar to Rosin-Rammler, but includes a term for the "fish hook" effect for entrainment. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - Simple

|- | ReqdSolFracToOS || Input || Fraction of Feed solids reporting to the over size product. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - Whiten

|- | valign="top" rowspan="4" | Whiten.CalcMethod || d50 || The user specifies the d50 of the screen. |- | d50 with Beta || The user specifies the d50 of the screen and uses the Beta method to adjust for uncertainties in the finer fractions. |- | Aperture, Eff || The user specifies the Screen Aperture and Efficiency. The unit then calculates the d50 of the Screen deck. |- | Aperture, Eff with Beta || The user specifies the Screen Aperture and Efficiency and uses the Beta method to adjust for uncertainties in the finer fractions. The unit then calculates the d50 of the Screen deck. |- | Whiten.Aperture || Input || Only visible if one of the two Aperture CalcMethods are chosen. The Screen Aperture, used to calculate the d50. |- | Whiten.Efficiency / Eff || Input || The Whiten Efficiency of the Screen.

  • If the user selects one of the 'Aperture' methods, then this is used to calculate the d50.
  • If the user selects one of the 'd50' methods, then this value is used to calculate the Screen aperture (see Theoretical Nominal Screen Aperture).

|- | Whiten.d50 || Input/Calc || If either of the d50 methods are chosen, this is entered by the user. If the Aperture method is chosen, this is a calculated value. This is the particle size with a 50% probability of reporting to the over or under size. |- | Whiten.Alpha || Input || The Efficiency parameter, alpha. An alpha value of between 8 and 15 is normal for screening. However, this does depend on the screening conditions and hence experience and/or test or plant data is required for accurate results. |- | Whiten.Beta || Input || Only visible if the d50 with Beta or Aperture,Eff with Beta CalcMethods are chosen. The Beta Efficiency parameter. This value takes into account uncertainties in the finer size fractions. |- | Whiten.Beta* || font style="background: #ebebeb" | Calc || Only visible if the d50 with Beta or Aperture,Eff with Beta CalcMethods are chosen. Efficiency parameter. |- | Whiten.MaxSizeToUS || Input || The model will ensure that all particles LARGER than this size all report to the Screen deck oversize product. This value is often = Screen Deck Aperture. (See Model Theory above). |- | Whiten.MinToOS || Input || The model will ensure that a minimum fraction of solids in each size distribution reports to the oversize product. For example, if the user specifies a minimum of 5%, then at least 5% of each size distribution will report to oversize. (See Model Theory above). |- | Whiten.Rf || Input || The proportion of feed liquid reporting to the over size product to be used in the fines calculation.
Note: This value is only used to adjust the solids fine fraction to the screen oversize and NOT to set the fraction of liquid reporting to the oversize stream. |- | colspan="3" font style="background: #ebebeb" | If the user has selected SolidMethod=Whiten and Whiten.CalcMethod = d50 or d50 with Beta, the following fields will be visible: |- | colspan="3" font style="background: #ebebeb" | Theoretical Nominal Screen Aperture |- | Whiten.Efficiency / Eff || Input || The Whiten Efficiency of the Screen. Used to calculate the Screen aperture. |- | Whiten.TheorAperture || font style="background: #ebebeb" | Calc || The calculated screen aperture, based on the specified d50, alpha and efficiency. Refer to equation 2 in Whiten Method. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - Karra

|- | valign="top" rowspan="2" | Karra.CalcMethod || d50|| The user specifies the d50 of the screen. |- | Area || The user specifies the Area and Cut aperture of the screen and the model calculates the d50 of the screen. |- | Karra.d50 || Input || Only visible if CalcMethod=d50. The user specified d50 of the screen. |- | Karra.TotalArea || Input || Only visible if CalcMethod=Area. The deck area. |- | Karra.Aperture || Input || Only visible if CalcMethod=Area. The deck cut aperture. |- | Karra.Wet|| Tick Box || Only visible if CalcMethod=Area. This must be ticked if this is a wet screening application. |- | Karra.Factor || Input || Only visible if CalcMethod=Area. This is a tuning factor that may be used to adjust the calculated d50 of the screen deck. The default value is 1. |- | Karra.MaxSizeToUS || Input || The model will ensure that all particles LARGER than this size all report to the Screen deck oversize product. This value is often = Screen Deck Aperture. (See Model Theory above). |- | Karra.MinToOS || Input || The model will ensure that a minimum fraction of solids in each size distribution reports to the oversize product. For example, if the user specifies a minimum of 5%, then at least 5% of each size distribution will report to oversize. This accounts for fines adhering to coarse particles or fines in the liquid. |- | Karra.Calc_d50 || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The calculated d50 of the deck, using the Karra equations. |- | Karra.d50 || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The d50 that is used to determine the screen partition curve. This is normally equal to the field above. But, if the calculated d50 > screen deck aperture, then the model will use the screen deck aperture. |- | Karra.FeedOversize || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The fraction of oversize material (Q) in the Feed to the deck. |- | Karra.FeedHalfsize || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The fraction of half size material (R) in the Feed to the deck. |- | Karra.FeedNearsize || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The fraction of near size material (Xn) in the Feed to the deck. |- | Karra.SolQmPerArea || font style="background: #ebebeb" | Calc || Only visible if CalcMethod=Area. The calculated solids flow rate divided by the screen area. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - Rosin-Rammler

|- | RR.d50|| Input || The user specifies the d50 of the screen, the size which divides equally between oversize and undersize. |- | RR.Sharpness|| Input || The user specifies the sharpness factor for separation, high values for sharper separation |- | RR.MaxSizeToUS|| Input || The maximum size allowed to report to undersize. |- | RR.MinToOS|| Input || The minimum percent solids (from feed) to report to oversize. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - Lynch

|- | Lynch.d50|| Input || The user specifies the d50 of the screen, the size which divides equally between oversize and undersize. |- | Lynch.Sharpness (m)|| Input || The user specifies the sharpness factor for separation, high values for sharper separation. |- | Lynch.Alpha || font style="background: #ebebeb" | Calc || Calculated from the Sharpness (m), refer to Lynch Method for more information. |- | Lynch.MaxSizeToUS|| Input || The maximum size allowed to report to undersize. |- | Lynch.MinToOS|| Input || The minimum percent solids (from feed) to report to oversize. |- | colspan="3" font style="background: #ebebeb" |

Solid Method - DelVillar-Finch

|- | Finch.d50|| Input || The user specifies the d50 of the screen, the size which divides equally between oversize and undersize. |- | Finch.Sharpness|| Input || The user specifies the sharpness factor (m) for separation, high values of m for sharper separation |- | Finch.d0|| Input || The largest particle size affected by the fish-hook for entrainment function. |- | Finch.MaxSizeToUS|| Input || The maximum size allowed to report to undersize. |- | Finch.MinToOS|| Input || The minimum percent solids (from feed) to report to oversize. |- | Finch.Rf|| Input || Proportion of feed liquid reporting to the over size product. |-