Screw Press: 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

◙ Throughput (kg/h) The equipment mass throughput is used as a measure of the equipment’s capacity. it is defined as the mass flow rate of material that is fed into each equipment unit.	0	Positive
◙ Maximum Throughput (kg/h) The maximum equipment mass throughput available on the market.	100,000	Positive

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

Sizing

In Calculated (Design Mode), the user specifies the Maximum Throughput and the program calculates the Number of Units and the Throughput.

In Set by User (Rating Mode), the user specifies the Number of Units and the 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. In the absence of a cost correlation for screw press equipment in the literature, the built-in cost model is based on the following arbitrary cost correlation:

Cost = 1,000,000 (Size / 60) ^ 0.8

where the cost is in USD for 2017 and the size is in MT/h. This model uses the constraints that the smallest equipment available on the market has a rated mass throughput of 1 MT/h (minimum rated mass throughput) and the biggest equipment available on the market has a rated mass throughput of 200 MT/h (maximum rated mass 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. Similarly, if the rated mass throughput of the equipment considered exceeds the above maximum rated throughput, then the equipment’s purchase cost will be calculated based on the maximum rated throughput and not on the equipment’s rated throughput.

For more information on this equipment, see Screw Press.

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