This MIV organization was crucial to accomplishing a fast startup. The MIV approach was also critical to the success of SECCO’s strategy of using one control room for all 10 plants. To economically connect all the various systems, including 14 outstations, to one control room, all of their systems needed to be consistent. The MIV strategy was especially important because about two-thirds of SECCO’s inplant staff were fresh graduates, which required the company to depend on outside training and assistance.
Consequently, we created integrated project management teams consisting of SECCO employees, Emerson staff, and EPCs during the internal testing and factory acceptance test phase. Many of the staff stayed long nights, and sacrificed their Chinese New Year, May Day, and National holidays, which is a major sacrifice in China. The staff was extremely committed to the project.
The core Emerson/SECCO team developed the functional design specifications (FDS) over about five months, and then presented it to the plants’ control managers for review and fine tuning. A simulation was created for one heater of the ethylene plant, which enabled further specification refining with all the various graphics and control models. The simulation was also fine tuned for one of the polyethylene processes to enable better understanding of the process when writing the sequences template. The engineering manager in the core FDS team eventually became the master editor of the functional design specifications. Every new module anywhere in the complex needed to be created by him, so we could keep the 10-plant facility consistent. Besides being the master editor of the 1,000-page FDS, which included 14 sections and 14 appendices, this manager also became the master trainer, which also was key to a successful start-up.Applying Digital Automation
The complex’s digital architecture integrates 10 of Emerson’s DeltaV systems (See Figure 3 below)
with one global historian and remote operations functions. All 10 automation systems are managed from one centralized control room (See Figure 4 below),
which is something that wouldn’t have been possible without Foundation Fieldbus technology.
These Foundation Fieldbus devices and systems provided several advantages, including openness and intelligent asset management. Because the most appropriate instrumentation was selected for each process, not all the devices were available from Emerson. The ability to integrate other suppliers’ devices really brought out the flexibility of PlantWeb with Foundation Fieldbus because this automation technology is designed around an open, standards-based platform on which industry-wide devices can participate.
|FIGURE 3: 10 TIMES DELTA V|
Each of the 10 process plants has a Delta V distributed system with I/O, controllers,
and PlantWeb architecture that report to the central control room.
The decision to go fieldbus originated in 2001, when BP was reviewing technologies and setting the goals for the facility. Even at that time, BP viewed Foundation Fieldbus as a leading edge, but still mature, technology with advantages for end users. Especially during commissioning, these devices’ intelligence helped reduce the loop testing elements that would otherwise have been necessary in a traditional startup.
Based on benefits already secured, SECCO now requires all green-field projects to be implemented with Foundation Fieldbus technology. The massive scale and success of SECCO proves Foundation Fieldbus’ value for most major projects. Benefits include:
- Increased reliability and accuracy.
- More seamless, richer information, which eases troubleshooting and reduces resources required for maintenance. In fact, SECCO estimates that Foundation Fieldbus will cut its maintenance costs by approximately one-third.
- A means of preparing for the future. SECCO sees fieldbus as a leading-edge, quality technology with natural advantages, which will raise its standards and business practices, and help increase the complex’s net profit.
While SECCO knew that a fieldbus approach would save considerable cabling, a conservative approach was taken to devices connected on each segment. Designs were limited to no more than 12 devices, and the average ended up as five devices per segment, where each segment varies between two to 11 devices.
In addition, Foundation Fieldbus enabled performance of basic PID control in the intelligent field devices. The choice was made to locate the PID algorithms at the point of final control—in the valve controllers. This control-in-the-field (CIF) provides the improved reliability of a truly distributed control system. CIF also reduces communication traffic between the automation system and the field devices, further increasing reliability.
Only single-loop control was implemented in the valves. All complicated control, such as cascade and multielement strategies, is done in DeltaV’s digital automation system. Control function blocks can be performed in any of the field devices, or in the automation system, since it is an easy drag-and-drop software choice. This easy configuration will save time as we modify our ever-changing plant. In actual application, CIF was implemented with no major problems. The benefits haven’t been quantified yet, but long-term advantages are expected for the SECCO plant.
The complex’s intelligent field devices also deliver process and equipment health information to the AMS Suite in PlantWeb. While SECCO is still discovering the benefits of its asset management system (AMS), it has already proven valuable in key areas, such as the AMS Suite Intelligent Device Manager. This enables range verifying inside the transmitter, while the user sits in the comfort of the control room. Likewise, the AMS ValveLink application is being used to obtain valve signatures, so SECCO can monitor valve status, act to optimize performance, and avoid abnormal situations.