PETROM, located in Mogi das Cruzes City, in Sao Paulo State, decided to increase Phthalic Anhydride production and to provide a better performance of reactors. Petrom decided to invest in the automation to improve the process control and also to increase the safety. These requirements could be reached using a reliable control system. With the new investments the plant will have an annual production capacity of Phthalic Anhydride of 80,000 tons, 90,000 tons of Plasticizers and 3,600 tons of Fumaric Acid.
The system automation was designed to control 3 Phthalic Anhydride reactors and a vacuum distillation tower, totalizing 1200 I/O points. The advantage of having the interfaces, field devices and the controller near to the application reduced considerably the installation costs. The conventional instrumentation was integrated using ET200M interfaces.
In terms of network cabling, the PROFIBUS DP segment has 800m and the PROFIBUS PA has 1300m. Althoug the cost of PROFIBUS instrumentation is slightly higher than the conventional one, the costs were absorbed by the reduction of commissioning and startup time, simple and fast diagnoses and maintenance of the system.
The main gain in terms of installation in this application due to PROFIBUS is concerning to the cable reduction due to the decentralized panel, the panels and conduits reduction. If the system was implemented in conventional 4-20mA technologies, it will be necessary more than 15,000m of cables for digital and analog signals. With PROFIBUS use there were 40% of reduction of costs in terms of installation. More than 100 field devices were supplied by smar for this PROFIBUS PA process automation solution.
Petrom automation technician Marcos A. Cusma says:
"The challenge of implementing this new technology in an operating plant was recompensed by the fact that future implementations will become simple tasks. Besides that, the training of all involved persons made work with PROFIBUS very easy. When Petrom assumed the project engineering gave us the capacity to know all details of installation, configuration and the opportunity to change the structure for better performance always when necessary. System interoperability and startup were excellent and the plant is operating very fine in its first step. The cost reduction and the simplicity of Profibus were confirmed and now we are observing maintenance behaviors, which also show a great improvement. Petrom has Smar as a technologic partner due to the quality of field devices during the time. This partnership brings us benefits since the technical support provided during the specification phase in the application and also after sales has contributed to keep a high operational availability of our plant. We are looking forward to the next plant steps".
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