A tank terminal’s revenue partially depends on its speed of transferring product from and to its storage tanks. The more efficient this transfer process, the more throughput the terminal realises, thus producing more revenue. But how do manually operated terminals speed up this process without heavy investments in automation?
Connected manual valves decrease line-up time
Before product transfer commences, the correct storage tank must be lined up with the associated berth. The time it takes to line up all of the manual valves involved is an important part of the overall transfer time. Decreasing manual valve line-up time therefore has a strong impact on the terminal throughput. Decreasing line-up time can be done without automation by connecting manual valves to the terminal control system.
1. Monitor valve positions in real-time
The most straightforward way to connect manual valves to a control system is with valve position indicators (VPIs). These devices transfer on and off signals to the control room to offer real-time manual valve status information. With the use of VPIs, operating errors are instantly detected and can be rectified in time to avoid operator errors.
VPIs are added onto any kind of handwheel operated valve to send an I/O signal to the control system. The system uses this input to calculate the valve line-ups and condition the progress of the loading process. The valves remain freely operable so operators can still make mistakes, but any incorrect operation is instantly signalled in the control room.
2. Monitor and restrict manual valve operation
Alternatively, mechanical valve interlocks are used to control manual valve operation whilst obtaining valve status information. Interlocks mechanically block unauthorised valve operation unless dedicated operating keys are entered. A key management system stores and registers these keys to derive valve status information from them and share this input with the control system.
This solution minimizes the risks to unauthorized valve operation and wirelessly provides insight in the status of each manual valve. The solution offers a high level of control over, and optimal insight in manual operations.
3. Control manual operations through system integration
More rigorous process control is reached by integrating an interlock key management system with the terminal control system. The control system controls manual valve operations by controlling the issuance of interlock operating keys. Only those keys required are issued to an operator. All other keys are unavailable.
With an interacting key management system, the control system has full control over manual valve operations. This means that the required operations are determined and authorized by the control system. This eliminates every risk of human error in lining up manual valves and ensures first-time-right operation.
Bridging the gap between manual and automation
These solutions bridge the gap between manual and automated valve line-up operations. They offer a range of alternatives to increase the throughput for the many bulk liquid terminals that are built with limited automation, without heavy automation investments.