Understand Product Injection Verification and Control
- Last UpdatedApr 24, 2025
- 4 minute read
The Product Transfer Checking (PTC) application provides the ability to automate Product Injection Verification and Control. This feature allows the system to automatically send an ON or OFF command to a status or multistate point that serves as a permissive for injection. The decision to send an ON or OFF command is based on compatibility between the product at the source (Batch Transfer or Virtual Flow Computer), and the product at the destination (Node). Compatibility is defined as an exact product match between the two products.
An upstream no-injection zone and a downstream no-injection zone ensure that the injection only occurs into the heart of the product and away from the batch interfaces, as shown in the diagram below. There are also upstream and downstream warning zones in order to receive audit events in advance of sending an ON command (which occurs after the downstream no-injection zone ends), or sending an OFF command (which occurs after the upstream no-injection zone begins).
If a Control Delay is configured, a wait period will be observed in between sending commands to the status or multistate point. That is, after sending an ON or OFF command, the system will not send another command until the Control Delay has passed, even if the system observes a reason to do so. It is important that the Control Delay be accurately specified by the Administrator based on typical batch sizes and flow rates for a given pipeline in order to avoid situations where the system may not react to a change in product due to a long Control Delay.
Example:
The following example illustrates how this feature works. The diagram shows a batch lineup passing through a Node at which we expect a source such as a Virtual Flow Computer to inject product. Elements labeled in green are configurable in the Product Transfer Checking record.
The following table lists the sequence of events expected to occur as the batch lineup passes through the injection location:
|
Location of Batch Transfer of VFC |
Product Compatibility |
System Behaviour |
|
|
Compatible |
Before location 1, even though the products at the source and the destination are compatible, the system does not send an ON command yet, because it is waiting for 150 barrels of the compatible product to pass through the node before it indicates that injection can start. At location 1, the system logs a warning event indicating that after the passage of 20 more barrels of the compatible product, the downstream no-injection zone will end and an ON command will be sent. |
|
|
Compatible |
At location 2, 150 barrels of the compatible product will have passed through the node. The system sends an ON command to the permissive multistate to indicate that injection can start, raises an alarm and logs an event. The injection does not stop at the batch boundary because there is no change in product. |
|
|
Compatible |
At location 3, the system logs a warning event indicating that after the passage of 30 more barrels of the compatible product, the upstream no-injection zone will begin and an OFF command will be sent. |
|
|
Compatible |
At location 4, the remaining volume of the compatible product is 100 barrels. Even though the products at the source and the destination are still compatible, the system sends an OFF command to the permissive multistate to indicate that injection should stop, raises an alarm and logs an event. |
|
|
Compatible |
At location 5, due to the incompatibility between the two products, no injection should occur. The system will do nothing since it had already sent an OFF command. |
Note: As a precaution, if the system detects that the flow rate in the pipeline segment is zero, it will not issue injection commands to the status or multistate permissive.