By Adrian Howell, Process Control Manager, SECCO SECCO
, a joint venture between BP, Sinopec and Shanghai Petrochemical Corp. (SPC), recently opened its huge, new petrochemical facility at the Shanghai Chemical Industrial Park in Shanghai Province, China, about 31 miles southwest of Shanghai. The $2.7-billion ethylene cracker complex (See Figure 1 below)
comprises 10 separate plants, with a main ethylene cracker capable of generating 900,000 metric tons per year (MTY) of feedstock. The other plants rely on this feedstock to produce polyethylene, polypropylene, styrene, polystyrene, acrylonitrile, aromatics and butadiene.
Each of the complex’s 10 plants is the largest of its kind in the world, enabling the overall facility to produce about 2.3 million metric tons of chemical products annually.
Rather than hiring a general contractor to oversee the project, SECCO decided to use an integrated project management team approach, in which each plant in the complex had a lead project contractor. A main instrument vendor (MIV) was selected to not only engineer and implement the automation and control systems, but also to help manage multiple international and local suppliers for each of the 10 plants. The alternative to working with one MIV would have been to work directly with many different instrument companies, which would have reduced construction efficiency and consumed much more time.
|FIGURE 1: CHINA SYNDROME|
The SECCO complex near Shanghai in China comprises 10 separate plants, with a main ethylene cracker capable of generating 900,000 metric tons per year of feedstock.
also selected Foundation Fieldbus communications as a central feature of the facility’s automation approach. Foundation Fieldbus not only simplified the construction and commissioning phase, but plant officials also expect it to reduce maintenance costs by as much as one third.
Fieldbus technology also allows the complex to use truly distributed control. For example, many of the plants’ basic process control functions operate within the field devices themselves (See Figure 2 below)
, rather than in the main automation system.
The complex is the largest Foundation Fieldbus installation in the world. More than 10,000 of the plant’s 20,000 devices are networked with fieldbus technology to deliver digital process, control, and device diagnostics information. Overall, the complex includes more than 48,000 loops, with about 166,000 I/O tags. Approximately 25,000 points are hardwired to the automation system. There are more than 70,000 cables in the facility.Accelerated Schedule, Completion
The project’s main challenge was its aggressive schedule: to go from bare ground to a fully functional facility in two and a half years. As plans were developed, one major goal was to have the plant operational by July 2005. At the time, that target date seemed impossible. However, construction of some facilities started in early 2003, the bulk of the work was finished before the end of 2004, and the plant went online in March 2005, in what was considered to be a phenomenal success.
To ensure a smooth launch, the complex’s downstream plants were started prior to the ethylene cracker, relying on imported feedstock to ensure everything was working properly. The plants did very well. In particular, the polypropylene unit came online very smoothly. The unit even ran out of feed, and it was necessary to shut the plant down to wait for our own olefins unit to come online. Mechanical completion for all 10 plants was completed on Dec. 28, 2004. The downstream plants went online in February 2005, and the ethylene startup was March 18, 2005, which was more than four months ahead of schedule.
In addition, the ethylene cracker was running on-spec in just 10 hours and 45 minutes. Considering the complexity of building 10 units at one time, and expecting all of them to start up in a short time frame, the timing achieved is amazing. Moreover, it was done with minimum disruption, very quickly, and achieved high levels of performance almost immediately.MIV Method
Previously, SECCO decided that using an MIV approach would be best for the project. The MIV would work with SECCO to implement the automation and control systems, and help manage multiple international and local engineer-procure-construct (EPC) suppliers for each of the 10 plants.
After evaluating several suppliers, SECCO selected Emerson Process Management
for its breadth of digital automation, including field instrumentation and systems, and for its experience in managing large-scale projects. Emerson had excellent resources in China, and could call on its global resources, specifically from its engineering centers in India and Singapore, to supplement its local resources.
Emerson and SECCO created framework agreements for all EPC contractors to use, enabling consistency across the site for current and future operations. This was vital to achieving SECCO’s long-term goals of ease-of-use and reduced maintenance by making sure that every process in the 10 plants was developed consistently.
|FIGURE 2: FIELDBUS CONTROLS|
|All single-loop PID control functions are accomplished in local fieldbus devices.|
As MIV, Emerson developed functional design specifications, and communicated and enforced conformance and standardization by every vendor throughout the facility, which was a vital step in maintaining operating efficiency in the tightly integrated complex. Emerson actually provided separate teams for each of the 10 plants, rather than having one team move from one plant to the next. Emerson also appointed a program director and an engineering and quality manager to oversee the plants.
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.
These asset management capabilities will improve the lifespan of the complex’s assets by enabling performance predictions, and allowing staff to prevent problems before they occur. For example, it’s possible to look at information coming from the intelligent valves, and understand changes in the friction coefficients to learn if there’s a potential for leakage or early breakdown.
The predictive diagnostics of PlantWeb and AMS Suite will help optimize our maintenance plan, enable personnel to focus directly on problems, improve efficiency, and minimize downtime. Knowing what the problems are beforehand, the staff can schedule maintenance and obtain needed parts. Where there are no problems, the maintenance schedule can be revised to alleviate delays elsewhere. This is a clear advantage over traditional plants that may have to tear down and rebuild equipment every two years, whether or not it is needed.Importance of Teamwork
The project team was able to meet and beat our project’s aggressive schedule because of teamwork. The technical staffs had tremendous rapport, which helped complete the project efficiently and successfully. Emerson gave SECCO a lot of support in the negotiation process, adopting a relatively flexible strategy that allowed us to reach agreements with the various EPC suppliers and sign an extremely efficient MIV contract. Following that, Emerson also provided support during the engineering construction process, which allowed intimate coordination with the EPC suppliers throughout the project.
|FIGURE 4: CAN WE SERVE YOU?|
|The central control room is a command center with a central server that runs asset|
management and maintenance management software for all 10 plants.
The most vital aspect of any petrochemical facility is reliability of the control system and a high level of reliability. This helped SECCO gain a strong competitive edge in the complex’s instruments. In fact, control of the plants will rely much more on the automation equipment than on the operators. Judging from the short amount of time in operation, SECCO’s overall manufacturing performance is more efficient and stable than it would have been with other automation.Assessing the Project
SECCO’s Shanghai project has been an unqualified success, and the complex will create a huge impact both locally and internationally. The project established a new record in going from bare ground to a fully functional ethylene cracker complex in just 27 months. The quality of the product is good, and the capital investment was completely within budget.
The project also achieved a worldclass safety record, with zero fatalities during construction out of more than 50 million man hours worked. The site also boasts leading environmental standards.
Installing Foundation Fieldbus was truly a non-issue. There were no significant problems and, in fact, it was much easier than with traditional instruments. Basically, whatever you can think of can be performed very well with this system, even the most complicated functions. Our challenge for the future will be to fully capture the value, and really build on the use of the technology.
Adrian Howell is the Process Control Manager for SECCO
, a joint venture between BP, Sinopec and Shanghai Petrochemical Corp., which recently opened its huge, new petrochemical facility at the Shanghai Chemical Industrial Park in Shanghai Province, China.