Petrobras is Brazil's largest energy and oil company, possessing 95 production platforms and 15 refineries with a throughput of 1,8 million barrels of crude oil per day. One of its most important facilities is Petrobras REVAP (Henrique Lage Refinery), which daily produces 226 000 barrels of petrol, diesel fuel, jet fuel, LPG, asphalt and sulphur.
Located in Sao José dos Campos, Sao Paulo State, Petrobras REVAP was planned in the late 1970s and was inaugurated in 1980. Its production was first based on low-viscosity crude oil, but this was later switched to Brazilian offshore crude with high levels of grit and coke. In time, this switch led to serious valve problems in the refinery's direct-fired heaters.
Blockage and leaks
Direct-fired heaters, which bring crude feedstock to the correct temperature for distillation, contain a series of tubes called passes. Each heater contains 6-8 passes, each of which has its own control valve. At Petrobras REVAP, these pass valves were double-seat globe valves, which seized up when they became encrusted with grit and coke from the viscous oil. They also led to serious oil leakages, which created a fire hazard.
In 2001, the corrective maintenance of these valves had become costly in terms of labour and productivity. Shutdowns of the distillation process were required in order to clean the valves every 2-3 months, and there were often problems with local environmental departments.
To improve the situation, Petrobras turned to Metso, with whom the refinery had cooperated since the installation of a maxDNA distributed control system. This maxDNA system, which is the world's largest, was installed during Petrobras REVAP's construction and controls all of its operational systems.
Combined benefits
When Metso began investigating valve options for Petrobras, both Neles MBV metal-seated ball valves and Top 5 heavy-duty rotary control valves were considered. The Top 5 valves were installed initially and provided good initial results. Later tests were conducted using 16 Neles Finetrol valves with Q Trim. This proved an even better solution for controlling the flow of crude oil in the direct-fired heaters.
The high-performance Finetrol valves offered Petrobras the control benefits of linear valves with the inherent benefits of rotary valves, such as freedom from clogging and leakage. They could be installed with the same face-to-face dimensions as the globe valves, which meant economical installation without pipework changes. Combined with smart valve controllers and Metso Field Care configuration and condition monitoring software, they meant new opportunities for predictive maintenance.
Reliability
Today the Finetrol valves at Petrobras REVAP are all running smoothly. Thanks to information provided by the Field Care software, Petrobras can reliably predict any valve problems and take preventive action. This has meant an end to crude oil leaks and unscheduled refinery shutdowns, and the ability to plan maintenance has lowered maintenance costs and reduced the need for spare parts.
In fact, the reliability of the Metso solution has led Petrobras to adopt Finetrol as the answer to most flow control problems involving high-viscosity, high-temperature oil products in heater passes. As a result, Neles Finetrol is the valve type most recommended to sites with similar process conditions in Brazil and elsewhere in the world.
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