The structural integrity of a gas pipeline and the assurance that the interior of the pipeline is contaminant-free are the two most critical elements in its construction. For this reason, the 150-kilometre gas pipeline between Sasol’s Secunda and Sasolburg plants required the supply of reliable and proven compressors.
“Rand-Air’s Atlas Copco oil-free compressors have a gained a solid reputation in the market for their ability to provide customers with quality assurance across the board. There are a number of instances where a variety of our - normal and high-pressure oil-free compressors have been effectively used for both dewatering and cleaning of pipelines,” says Louwrens Erasmus, General Manager of Rand-Air.
The Sasol pipeline projects extend over three provinces – Mpumalanga, Gauteng and the Free State – and was awarded to a joint venture between WBHO and SPIECAPAG. SPIECAPAG is specialised in the delivery of onshore pipelines and facilities such as compression, pumping and metering stations, hydrocarbon storage systems, slurry pipes and water pipe networks. The company has laid over 50 000 kilometres of pipelines covering the five continents, for the most challenging and complex projects.
Benoit Patanchon, Plant and Logistics Manager for the JV SPIECAPAG/WBHO selected two Atlas Copco oil-free compressors from Rand-Air, based on the performance of these compressors on a similar project. In addition to the two 2 4 bar oil-free compressors, the company also hired three 300-400- cfm and one 1 000- cfm compressors at 7-bar pressure from Rand-Air.
“The two 2 4bar oil-free Atlas Copco compressors are being utilised for the hydrotesting, cleaning and drying of the pipeline. Oil-free compressors are both a technical and safety requirement on site. We simply cannot afford to allow any external contaminants to be introduced into the pipeline, due to the very high cleanliness specification of our client” says Benoit.
Apart from the quality considerations, it is critical that no heat is generated inside the pipeline. “Since gas is extremely flammable and volatile, it is extremely important that the internal pipeline environment is carefully controlled to ensure maximised safety levels,” Benoit explains. Benoit points out that the smaller compressors provided by Rand-Air are used for blasting and pipeline coating and civil works.
Pre-testing of the pipeline is undertaken, using the 1 000- cfm compressor, after the pipeline is laid. This ensures that the pipeline is contaminant-free and that the structural integrity of the pipeline is not compromised. “There is no margin for error, so we need to ensure that the pipeline is 100% leak-free. Once we are satisfied with the structural integrity, we use the oil-free compressors to push pigs through for cleaning and final drying of the pipeline section.”
The smaller compressors will be used for six months by the coating team. Similarly, the larger 1 000- cfm compressor is expected to be on site for a six-month period. The time that the compressors are kept in a specific location is dependent on the length of each section.
“We will need the oil-free compressors for approximately three to four months. During this time we will push them to their capacity, as they will be required to produce pressures capable of covering distances of up to 25 kilometres,” adds Benoit.
Benoit explains that once a section of the pipeline is completed, the team moves on to a new section, 11 testing sections are scheduled on the GNP project.”
Benoit says that the company has been happy with the performance of the compressors and the level of service provided by Rand-Air. “We work in excess of 12 hours per day, seven days a week, sometimes in double shifts, day and night, so we expect nothing less than the best quality equipment and fast reaction times from our suppliers. Any issues need to be rectified immediately, so we depend on companies like Rand-Air to have similarly high service delivery levels.”
“It is important for Rand-Air to exceed our customer’s expectations. All of the machines we sent to site have provided exemplary service and met all our expectations in terms of delivery and support to our customer,” Louwrens concludes.