Material Storage Units
A material storage unit can be used to supply material or receive (collect) material. There main purpose is to track the consumption or production of material at specific points in the process. For information on how to create storage units in the process, see Registered (in use) Material Storage Units.
•Supply Storage Units
Supplying storage units may deliver material directly to any bulk input streams. This will basically initialize the contents of the input stream. Certain operations can also utilize supplying storage units in order to bring material in to the hosting equipment by not using a physical stream of the process (stream represented by a line in the flowsheet).
•Receiving Storage Units
Receiving storage units are used to collect material directly from any bulk output streams. Certain operations that don’t output material on physical streams of the process may also use receiving storage units to deposit their material. Finally procedures may dump the contents of shared equipment to receiving storage units.
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For every new process model, the application will automatically create two receiving storage units, both classified as ‘Aqueous Waste’:
- “CIP Waste”, and
- “SIP Waste”
For each cleaning step created in a CIP operation, the application will automatically assign its output (waste) to be collected by the “CIP Waste” unit. This way, when the process model is finished, it is easy to track all the CIP waste generated by the process: simply request to see a chart for the “CIP Waste” storage unit (select }}}}). You can view the cumulative amount collected as well as the rates of deposit in the span of a single or multiple batches. Furthermore, you can do inventory analysis on the CIP waste in order to design the size and the removal frequency of the CIP waste holding tank.
Similar handling is applied to all SIP operations created in a model: the “SIP Waste” storage unit is automatically assigned to each instance so that by the end of the model, the SIP waste can be easily traced.
If users have the need to use multiple receiving units for CIP waste collections, that can be easily accomplished by creating multiple receiving storage units and assigning the appropriate steps to its corresponding receiving unit.
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More specifically Material storage units may be used in the following ways:
Supplying Storage Units Usage:
● Bulk Streams (Input): The contents of a bulk input stream can be initialized from a storage unit. The assignment of a supply unit to an input stream is done through the Assign Storage Unit Dialog.
● Gas Sweep Operation: The gas sweep operation requires a sweeping agent which can be provided from a material storage unit.
● Pressurization Operation: This operation requires a pressurization gas to be carried out, the material that the gas is composed of can come from a storage unit.
● Purging / Inerting Operation: The purging gas of this operation can originate from a storage unit.
● Cake Drying (in a Nutsche Filter) Operation: The cake drying operation in a nutsche filter can optionally carry out a gas sweep during drying, requiring a gaseous material which can be supplied by a storage unit.
● Clean-In-Place (CIP) Operation: The CIP steps of an In-Place-Cleaning (CIP) operation can optionally obtain the cleaning agent from a material supply unit.
Receiving Storage Units Usage:
● Clean-In-Place (CIP) Operation: The CIP steps of an In-Place-Cleaning (CIP) operation can deposit the cleaning agent they use in to a receiving storage unit. Optionally one of the CIP steps can also remove the remaining contents of the vessel as waste together with the disposed cleaning agent, and deposit them in the storage unit. Note that by default, the application will assign the waste output to the “CIP Waste” receiving unit that is automatically created in each process model (see above in this section).
● Steam-In-Place (SIP) Operation: The SIP operation can deposit any material that is associated with the Heat Transfer Agent it uses, into a receiving storage unit. Optionally it can also remove the contents together with the utility material, and deposit it in the storage unit. Note that by default, the application will assign the waste output to the “SIP Waste” receiving unit that is automatically created in each process model (see above in this section).
● Sampling Operation: The amount of material removed for sampling purposes can be deposited as waste in a storage unit.
● Local Receptacle & Automatic Emptying of Contents: When an equipment is shared by more than one procedure, its leftover contents may be emptied as waste before it is re-used. This leftover material may be deposited in a receiving storage unit.
● Bulk Streams (Output): The contents of a bulk output stream can be deposited in a storage unit. It is required that both output stream and receiving storage unit have the same classification. The assignment of a receiving unit to an output stream is done through the Assign Storage Unit Dialog.
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Once a storage unit (supply & receiving) are associated with a stream or an operation, then the storage unit is the one that defines the material for supplying units or the classification, treatment/selling price for receiving units. The composition in input streams and the classification of output streams cannot be changed. All options in operation which are related to the associated storage units are disabled.
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Tracking Material Amounts
Using storage units you may designate the tracking of the consumption or production of material to specific points in the process. This way it is possible to assess how much of a material is required or outputted by a particular operation, unit procedure or section in the process.
The demand in the amount supplied by a storage unit is calculated by the operations that consume the material. Similarly the operations or procedures (if procedure is set to dump leftover contents of equipment before re-use) will also define the total amount of materials that are outputted to receiving units. SuperPro Designer keeps track of the instantaneous as well as the cumulative amounts of material that the storage units may supply or receive.
Registered (in use) Material Storage Units
New storage units can be registered in a process file by selecting } } } or } } from the main menu or } from the flowsheet’s context menu. From the Material Storage Units Dialog interface that appears you may:
● Create supplying units or receiving units through separate tabs by clicking on the Add button (
). You will presented with a dialog that allows you to enter the property data for the creation of a new material storage unit.
● Edit the properties of storage units by clicking on the View/Edit button (
). You will be presented with the same dialog used for adding a new material storage unit.
● Delete storage units by clicking on the Delete button (
).
See Material Storage Unit Properties for details on the various properties of supply and receiving material storage units.
In order to make use of a storage unit you must visit the available usage points (streams, operations or unit procedures) as mentioned previously in the Material Storage Units, and select the appropriate storage unit from a list of registered supplying or receiving units. Please note that when selecting a supplying unit this will change the composition of the input stream or the inputted material of the operation, to the composition of the supply unit. And when selecting a receiving unit you will only have the option to select a receiving unit which is compatible by classification. For example you can not associate a CIP step with a receiving unit whose classification is revenue, the CIP step may only remove the contents as waste.
Material Storage Unit Properties
The parameters of a storage unit can be inspected or edited by choosing the supply or receiving tab from the Material Storage Units Dialog interface accessed by selecting } } } or } } from the main menu or } from the flowsheet’s context menu.
To view or edit the properties of a storage unit you should click on a storage unit index row to select it and then press the Edit button (
). Alternatively you can double-click on the storage unit row. The dialogs that comes up contains the supplying or receiving units data respectively organized in four tabs.
Supply Unit Properties
The properties tab for a supply unit (List of Material Supply Storage Units Tab) lets you define the name of the supply unit, the material supplied, whether the basis is per mass or volume and the density to convert between mass and volume. The density is not the density of the material but the density in the storage unit. This may differ from the density of the material in the associated input stream or operation. The material cost and units displayed is the cost and units of the registered pure component or stock mixture.
Receiving Unit Properties
The properties tab for a receiving unit (List of Material Receiving Storage Units Tab) lets you define the name of the receiving unit, the classification of the deposited material, whether the basis is per mass or volume and the density to convert between mass and volume. Again the density is not the density of the deposited material but the density in the storage unit. A receiving unit may accept different pure components and/or stock mixtures. You may optionally specify the selling price (revenue or credit classifications) or waste treatment cost (waste classification) and the basis units.
The Availability Limits tab lets you define bounds on consumption or exiting material of a storage unit. There are two types of limits: rate limits (instantaneous or time-averaged over a user-defined time span) and cumulative limits over a user-defined time span. Upon request, these limits will be plotted on the resource consumption charts (see Material Supply & Receiving Unit Rate Charts) so that you can compare them against the actual consumption.
The Inventory Data tab lets you define storage and supply data of the material in a storage unit, in turn, it will be used to calculate the inventory chart lines (see Material Supply & Receiving Inventory Charts). See also Material Inventory.
The locations where a storage unit is currently utilized in the process can be viewed by clicking on the button 
. This can be in operations or streams (input or output), which are displayed in order of first use accompanied with their hosting procedure.
Finally the evolving composition of the contents of a receiving unit, as several material deposits would come in the span of a complete process batch execution, can be viewed by clicking on the button 
. In the case of continuous processes the contents of each deposit is displayed separately in the table with the total sum of all the deposits in the last column. The environmental properties for each of those contents states can also be viewed by clicking on the button 
.
Cascading Storage Units
Oftentimes, supplying a specific material (e.g. “WFI” or “Buffer-A”) requires the availability of one or more predecessor materials. For example, “WFI” supply will need to be replenished with “Purified Water” or “Buffer-A” may need “H2SO4 (10%)”, “HCl (25%)” and “Purified Water” to be available for preparing “Buffer-A”. Therefore the demand for replenishing “WFI” or “Buffer-A” (when needed) can be translated in demand for “Purified Water” and/or “H2SO4 (10%)” and/or “HCl (25%)”. SuperPro provides the notion of cascading storage units to allow users to model such interdependencies between the demand for materials. Assuming one has created supply storage units for all of the above, you can specify in the definition of “WFI” storage unit that it is being replenished from the “Purified Water” storage unit with a replenishment factor of 1.1: in other words to have 1kg of “WFI” available in the “WFI” storage unit one needs to draw 1.1 kg of “Purified Water” from the “Purified Water” SU. (see Material Storage Units Dialog). When generating the inventory chart for any such supply SU (with cascading SU dependencies) any time the SU requires replenish at a specified rate, this will automatically be mapped as demand (or consumption) rate to all cascade storage units at a rate that is determined from the material factor.
An exactly equivalent concept can be defined for receiving storage units whereby any time material needs to be drawn to empty the receiving SU, it is automatically generating a filling rate to the cascading receiving SUs.