Hobbs Valve Triple Offset Butterfly Valves solution in harsh chemical application

The Problem: Harsh chemicals eroding the materials on standard butterfly valves

A major petroleum company in Oman, The Occidental’s Mechanical Vapour Compressor (MVC) facility were experiencing severe wear on the valve seats and discs of the standard buttefly valves they had installed in their plant. The plant incorporates a mechanical vapour compression (MVC) brine concentrator to treat produced water from oil and gas extraction and consists of seven identical MVC trains each with the capacity of 42,860 barrels per day, giving a total capacity of 47,700m3 per day.

The strong chemicals the plant was using to treat the water included Ethylenediaminetetraacetic acid (EDTA), Citric acid, Surftreat, Trisodium phosphate and Diesel. These chemicals were eroding the materials (cast iron, 316 stainless steel and EPDM) of the standard butterfly valves, causing costly breakdowns and replacements.

The Solution: Hobbs Valve Triple Offset Butterfly Valve in Super-Duplex

With the help of Hobbs Valve in the UK, MGA Controls Ltd (A Technical Solutions provider) specified Hobbs Valve 8” Triple Offset Butterfly Valves in Super- Duplex 6A stainless steel.

How did the Hobbs Valve product solve the problem?

The operation of Hobbs valves is such that contact of materials is only made at the last possible point in the valve movement – The two sealing components only come into contact at the final 0.01 degree of valve movement.

Benefits of Triple Offset Technology:

• Less wear on moving parts
• Increased valve working life due to friction-free stroking
• The materials and method of operation allow for full metal to metal sealing
• Durability against harsh chemicals used in the treatment facility
• Zero leakage when the valve is in the closed position
• Low torque required to open or close the valve
• A smaller actuator is required to operate the valves, resulting in a lower cost of automation - a direct result of the friction-free stroking and operation of the valve.
• Reduced life costs and less maintenance

Hobbs Valve hold a patent for having 2 removable sealing components and only one possible leak path. The end user can stock the 2 spare parts for easy replacement: The disc is easily replaceable due to its “bolt-around-shaft” construction, and the sealing gasket is easily replaceable due to its removable body gasket.

As a result of MGA Controls and Hobbs Valve joint efforts, a technical solution was delivered to overcome the problems the Occidental MVC treatment facility were experiencing with valve breakdowns due to the aggressive environment they were operating in.