Centrifugal Sieve: Equipment Tab

Variable Definitions, Ranges and Default Values

The following table shows the meaning of the variables appearing in this tab, as well as their default values and their generally acceptable range. Note that due to the manner by which the variables are used by the sizing and costing equations, the range of acceptable values may be further reduced.

Variable	Default Value	Range

◙ Rated Throughput The total rated mass throughput.	0.0 kg/h	Positive
◙ Max Throughput The maximum mass throughput that a unit of this type is available for purchase in the market.	49,500 kg/h	Positive

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Sizing: Design Mode

In Calculate (Design Mode), the user specifies the Maximum Throughput and the system computes the Number of Units and the Rated Throughput. If the operating throughput exceeds the maximum throughput, then the system assumes multiple identical units operating in parallel with an operating throughput of less than the maximum.

Sizing: Rating Mode

In User-Defined (Rating Mode), the user specifies the Number of Units and the Rated Throughput. If the operating throughput exceeds the rated throughput of the step (which is equal to the rated throughput of each unit times the number of units), a warning message is displayed advising the user to increase the number of units or reduce the operating throughput.

Costing

The built-in and user-defined equipment purchase cost models are based on the rated mass throughput. By default, the built-in equipment purchase cost model is used to calculate the equipment purchase cost. This is based on a modified version (based on vendor data) of the cost correlation for horizontal basket centrifuges described in Coulson and Richardson’s Chemical Engineering Series, Volume 6, 4th Ed. (2005). This model uses the constraint that the smallest equipment available on the market has a rated mass throughput of 22 MT/h. This is the minimum possible value for the rated throughput. If the rated throughput of the equipment considered is lower than the above minimum rated throughput, then the equipment’s purchase cost will be calculated based on the minimum rated throughput and not on the equipment’s rated throughput.

For more information on this equipment, see Centrifugal Sieve.

For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.