At the beginning of 2011, two Pneumofore engineers travelled to India for the commissioning of six vacuum systems, model UV16 H B2500B, delivered to Narmada Offshore Constructions, a specialist in pigging and hydro-testing to serve the oil, gas and petrochemical industry. The pipeline is in Ujjain, near Indore and measures 48in (DN 1,200) diameter for 90km (56 miles).
Four double-stage vacuum systems with variable-speed-driven roots pumps as second stage (each 3,000m³/hr [1,770cfm] capacity) and two standard double-stage systems (each 2,500m³/hr [1,473cfm] capacity) for the total maximal flow of 17,000m³/hr [10,020cfm] were installed for the vacuum drying process.
Some vacuum units were installed in a 20ft container, others simply placed on the unpaved ground. All vacuum pumps were protected with inlet filters and connected to the central manifold. The special features of the Pneumofore vacuum system are the capability to evacuate water vapor, to be ready-to-use, completely air cooled and with unique efficiency. This solution was chosen due to the large volume in the pipeline, which had to be evacuated down to 0.3mbar(a) (29.905 inHg(V)) for the dew point of -38°C (-36.4°F). The drying with this dedicated vacuum system was economically far more convenient than the previous drying technique with nitrogen.
With a record of 5,000km (3,100 miles) tested cross country and offshore pipelines, Narmada Offshore Constructions is a major Indian player, offering a wide range of pipeline services, including cleaning, hydro-testing, dewatering, drying and pre-commissioning.
