What Information is Needed by Sigmafine?
Sigmafine requires two sets of information:
1) Information needed to create the Model that represents the facility process:
While the number or variety of elements that your Model encompasses does not change how a Model is stored, it does help in planning both the initial Model design and the information needed to complete a Model analysis and get meaningful results. When considering the scope of a model, remember that it needs to be small enough for the relationships between properties to be well defined, but large enough to have the necessary level of redundant data to get reliable data reconciliation results. Sigmafine will determine which measurements are redundant and determine the redundancy level for the model (DXO Attribute for Case Results element).
Depending on the type of user the modeling scope will be different. For example, an engineer looking at equipment performance of a section of the facility may need more detailed information than a resource planning individual who tracks materials throughout a facility. The planner needs measurements in the Model that are different from the measurement needs of the engineer. Elements that are common to both Models use the same source elements; this aids in the construction of a variety of Models using the same Element library.
The three main Sigmafine modeling levels are:
Boundary Model
This type of Model is mainly used by the Accounting Department for overall facility stock accounting and balance.
The features of this type of Model are:
Model that provides overall intakes and out-turns to the facility and inventory changes within the facility on a daily and/or monthly basis.
All process facilities are combined into one overall process block. No detailed connections between process units in the block are shown in the model.
Receipt points, shipment points and storage tanks are connected to this overall block.
In some Cases the flare system and the fuel system are shown in detail.
Plant-wide Model
This type of Model is used by the Accounting Department for overall facility stock accounting and by the Planning Department for unit operation yield accounting. It has good redundancy and a true value as a data reconciliation application. It can also be used to check the custody transfer meters for raw material and finished products.
The features of this type of Model are:
Facility Model in which all process units are shown as separate blocks defined by the process unit battery limit. This Model provides overall facility balance by considering receipt, shipments and inventory changes as well as individual unit balances by taking into account process units intakes and out-turns.
Connections between receipt points, shipment points, storage tanks and process units are shown in the model. The flare system and the fuel system are also shown.
The higher redundancy level (vs. the boundary model) allows verification of the process unit yields and detection of bad measuring points.
Unit Model
This type of Model is mainly used for checking individual unit operation yields and for ad hoc studies.
The features for this type of Model are:
Model that provides intakes and out-turns to the process unit at their battery limits and detailed connections between equipment within the process unit.
Receipt points and shipment points are defined at the process unit battery limits and connections of these receipts and shipment points to equipment within the process unit are shown in the model, as well as connections within the equipment in the unit.
2) Information needed to run the data reconciliation analysis:
The analysis is capable of processing very large and detailed models, but realistic results are only possible when the required information is made available. Each type of analysis has its own data requirements. For example, running a mass balance on a Model is only possible when material quantities are measured and can be resolved to mass. To get a mass from a volume a density measurement is required. To get a mass from a tank level the user need to have a relationship between the level gauge and the inventory volume and between the inventory volume and the inventory mass.