Technical Focus
S14 ORME 1 2012 Technical Focus 02_Layout 1 31/01/2012 15:19 Page 72
facilitates scheduled line maintenance. In preparation for planned line maintenance, TDW was retained to ensure that a key hydrogen sulphur line could be cut, plugged and safely isolated without shutting it down. The only other alternative would have been to shut the line and production unit down, resulting in a complete halt in production, which was deemed unacceptable.
Currently, TDW is in active negotiations with operators to carry out a number of STOPPLE Train intervention operations in 2012 With equipment from the company’s base in Nivelles, Belgium, a team of TDW technicians from Italy, Belgium and the United States used a standard 660 tapping machine to hot tap the line, and inserted one six-inch STOPPLE Train doubleblock and bleed plugging system to plug the line. The operation was successfully completed in just one day, creating a secure environment in which critical maintenance and servicing could be carried out. The fact that the line was isolated with a minimum amount of equipment and required only one fitting meant that costs associated with welding and fittings were significantly reduced. “The fact that the company’s first ever STOPPLE Train plugging system intervention operation in Europe went so smoothly, and that the customer benefitted in terms of enhanced safety and reduced
costs is extremely heartening,” said Georges Andrei, Hydrocarbon Process Industry Sales Manager Europe for T.D. Williamson SA. “The ability to create a safer working environment, reduce the time required to complete the job, and cut costs bodes well for operators everywhere.”
Preparing for valve change-out in Illinois, USA Further afield in Illinois, USA, TDW completed an isolation operation using the STOPPLE Train plugging system on a 10-inch diesel transmission pipeline that typically transports 1200 barrels per hour. 6 The isolation was necessary in order to prepare for safe and speedy replacement of an isolation valve on the line. After hydrotesting the equipment, TDW performed three downstream taps: one 2-inch equalization tap, one 10-inch tap for installing the STOPPLE Train plugging heads, and one half-inch tap for the purpose of bleeding the isolated section. After removing the tapping machine, TDW mounted the STOPPLE Train system and connected the equalization and hydraulic hoses. The team then stopped product flow and closed two valves located approximately ½-mile north of the work area. A single bleed port was then opened between the two valves, providing double block and bleed on the upstream side of the work area. The STOPPLE Train plugging heads were inserted, the isolated section drained and the bleed valve opened to provide double block and bleed on the downstream side of the work area. The isolation valve scheduled for replacement was removed and replaced with the new valve. The upstream valves were then opened and the line pressure equalized before removing the STOPPLE Train plugging heads. The plugging heads were then fully retracted, the housing removed and a completion plug set in the fitting. The entire process required just two days to complete. As a result, the customer was extremely pleased, particularly with the efficiency of the process.
Such was the case when TDW was called in to assist another customer near Lafayette, Louisiana. This customer needed to add a new isolation valve and replace part of an existing 8-inch natural gas liquids (NGL) pipeline. To facilitate this, TDW used two STOPPLE Train systems - placed upstream and downstream - to isolate a 1.3 mile section of the pipeline. The customer used pipeline batching pigs to replace the NGL with nitrogen through the section of the line to be replaced. The pigs were launched at intervals to create a 1,000-foot buffer zone of nitrogen on each side of the work area. First, the downstream STOPPLE Train plugging heads were set, followed by the upstream plugging heads. The customer then depressurized and bled down the 1.3 miles of nitrogen from the pipeline. After verifying that no product had leaked past the secondary seals of the STOPPLE Train plugging heads, the bleed valves were opened to ensure that a proper primary seal had been achieved. Following these critical verifications, the line was deemed safe to cut and open. Each end of the pipeline was cut within approximately six feet of each STOPPLE Train plugging head. The customer then tied in the new line and installed an 8-inch block valve 50 feet downstream from the plugging heads located upstream. After completing these modifications, the customer closed the new block valve, and TDW proceeded to equalize between each of the STOPPLE Train systems and the valve. Both systems were retracted and each completion plug was set. The customer was so impressed with the quality and efficiency of the operation, the company ordered two STOPPLE fittings to serve as part of its emergency response preparedness program.
Multiple applications
As these examples illustrate, the STOPPLE Train plugging system has been used successfully for operators seeking to carry out a broad range of applications. Enhanced safety and reduced costs are just two benefits that customers have realized when this innovative approach to piping system isolation has been used to prepare for scheduled maintenance, emergency repair work or tying in a new line. Line tie-in goes “The success of these and many other double to plan in Louisiana block and bleed isolations achieved with the When operators prepare to tie-in a STOPPLE Train plugging system is paving the way new line to one that is for further use of this technology,” said Fabry. “This operating, they must ensure is especially important as TDW moves forward with that the live section of the plans to carry out operations on behalf of pipeline, piping system is properly refinery and petrochemical plant operators isolated before work can throughout Europe, Africa and the Middle East.” proceed. Building upon its impressive track record in the United States—where TDW has carried out STOPPLE Train plugging system operations TDW STOPPLE Train Cutaway for nearly every major operator—the company is poised to dramatically expand this service. Currently, TDW is in active negotiations with operators to carry out a number of STOPPLE Train intervention operations in 2012. ■
72 Oil Review Middle East Issue One 2012