Tyco Valves & Controls has worked in close collaboration with leading Dutch oil and gas producer Nederlandse Aardolie Maatschappij (NAM) to ensure optimum performance from its Vanessa triple offset rotary process valves. The valves have been installed for isolation and control services in arduous thermal cyclic loading conditions, to provide zero-leakage operation and achieve the high frequency of valve operations required. On completion of a finite element thermal stress analysis, Tyco’s engineering team were able to carry out design modifications to the valve seat, specific to the application, thus doubling the life-span of the valves and enabling NAM to benefit from 14 years of continuous leakage-free operation. In a joint venture between Shell and Exxon, NAM is producing gas for Dutch concern Gas Unie, which is primarily used for domestic consumption and exported throughout Europe. In order to condition the gas to the desired specification, containing no more than 5 mg/Nm3 liquids at –3ºC and 33bar, the gas is dried by adsorption, which involves feeding it at approx. 80 barg through a bed of silica gel. In order to remove moisture and heavy hydrocarbons present in the gas, the bed is heated to a temperature of 280ºC by a hot gas flow diverted from the main gas stream. The bed is subsequently cooled to 40ºC.
