By: Irma Venter
7th February 2005
Funded by the city and the Sapref and Engen refineries, the pipeline report was commissioned after a series of underground pipe failures in recent years, which included a leak of more than 1,2-million litres of petrol in the Wentworth residential area in 2001.
Despite its recommendation to revamp thepipelines, the report has done little to alleviate the conflict between the South Durban communityand the two refineries, which have been at loggerheads about issues such as petrol spills and airquality since the 1990s.
Nestled next to the tall towers of industry,battle-weary residents of South Durban saythe only solution is to replace the pipelines, rather then the extensive refurb currently on the cards.
The first step
eThekwini Municipality city manager Dr Michael Sutcliffe says the city commissioned the pipeline study following a number of failures occurring in the recent past on the various transfer pipelines that run from the Engen and Sapref refineries to the Island View harbour facility.
“The city viewed these pipeline failures with concern and raised various questions in terms of pipeline integrity management practices, design specifications and whether the pipelines, in their current state, are fit for service. To my knowledge we are the first municipality in the world to commission such a study, which includes a peer review.” The study centred on researching the history of the pipeline network and associated integrity management practices of both refineries, with a view to understanding the root cause of the failures and determining future practices; assessing the current status of the pipelines and reviewing rehabilitation plans submitted by the refineries; and then finally submitting findings and recommendations.
The report was compiled by Pipeline Peformance Technologies (PPT), which privatised from the CSIR in 2000, with an international peer review conducted by Dirk van Oostendorp, from the US, who is a professional member of the British Instituteof Corrosion, and a certified senior corrosiontechnologist.
Oostendorp was chosen and fully paid for the peer review by the city council alone, notes Sutcliffe.
Sapref is a 50:50 joint venture between energy multinationals Shell SA Energy and BP Southern Africa. It is Southern Africa’s largest crude-oil refinery, with 35% of the country’s refining capacity, which equates to 180 000 barrels of crude oil per day or 8,5-million tons per year.
The refinery is located in Prospecton, about 16 km south of Durban. There are seven underground fuel transfer lines running about 12 km between the refinery and the Island View harbour facility.
The products transferred in these pipelines include diesel, petrol, naptha and marine fuel oil.
Between 1972 and 2003 Sapref had nine recorded leaks on its transfer pipelines, with eight of these leaks being a direct result of external corrosion.
The oldest pipelines are the naptha, liquefied petroleum gas, marine fuel oil (MFO) and automotive gas oil lines, commissioned in 1963.
The lubricating base oils and dual-purpose kerosene lines were commissioned in 1967, with the Mogas line, transferring various grades of petrol, commissioned in 1973.
Sutcliffe says PPT was unable to obtain accurately the leak history data on Engen’s transfer pipelines. However, it was established that there were leaks on some of the pipelines inside the Engen plant area and a leak on the fuel-oil pipeline.
Engen owns eight transfer pipelines that run from its refinery to the Island View complex and each covers a distance of approximately seven kilo-metres.
The products transferred by these pipelines include petrol, diesel, lube oils and white oils.
The oldest pipelines in the Engen stable are the white oils, unleaded petrol, bunker fuel oil and automotive diesel oil lines, commissioned in 1952.
The petrol and crude-oil lines were commissioned in 1970, the lube oil line in 1971 and the solvents line in 1977.
PPT reports that, since commissioning of its pipelines, Sapref has undertaken extensive intelligent pigging and has an ongoing pipeline rehabilitation plan, as well as risk-based assessment (RBA) and risk-based inspection (RBI) systems in place.
(Pigging, among other tasks, serves to clear debris from pipelines, to remove residual product and to gauge the internal bore of the pipeline.) The report also states that tightness and hydrostatic testing at Sapref is carried out according to international norms.
The report found that Engen’s two four-inch pipelines have not been pigged and that the other lines have only been pigged once.
It also states that the refinery has an ongoingrehabilitation programme.
Report shows maintenance inadequacies
The PPT report highlights numerous inadequacies by both refineries in the maintenance of the pipelines, many of which date back to the time of construction, says Sutcliffe. Also important though, he adds, is that bothrefineries “have made significant progress in addressing pipeline integrity over the past few years”. The report states that the root cause of thepipeline failures have been corrosion caused bystray currents, which is the predominant failure mechanism on the pipelines, caused by ineffective cathodic protection (CP) systems.
The report further states that the problem of stray currents has never been satisfactorily remedied and is the main reason why ongoing leaks have been encountered.
The CP systems’ effectiveness is reported to have been poor for decades and the study highlighted some of the problems with the existing CP systems.
(As a primary safeguard, underground pipelines carrying petroleum products are covered in a special protective wrapping. CP is a secondary protective system. If the wrapping breaks down, CP takes over to protect the pipelines from corrosion in the wet ground and to combat stray currents in the ground.) (Stray currents are caused by direct current (dc) traction on railway lines that could be up to 60 km away. Dc currents can leave the railway lines at certain points, move along metallic structures, such as pipelines, and eventually leave the metallic structure to return to the traction substation. Stray currents entering a pipeline are not a concern, but when they leave the line they can contribute to corrosion if the wrapping at that spot has broken down, Sapref communications manager Margaret Rowe explains.) The report also states that between the early 1960s and 1970s the external coatings on two of the pipelines under inspection were operated at significantly higher temperatures than the coating could withstand, which resulted in severe damage to the external coating.
In tackling the question of CP systems, thePPT report recommends that Sapref and Engen immediately redesign and upgrade their CP systems, undertake detailed stray current analysis to determine patterns; and install remote monitoring systems for all CP units.
Specific recommendations for Sapref include that its MFO and Mogas lines must be rewrapped by 2006, and that pigging must be done on an annual basis until one year after a new CP system has been installed and is operating as designed, and the MFO and Mogas lines have been rewrapped.
Sapref must also immediately finalise its detailed assessment programme and must clearly define its integrity management plan.
Recommendations for Engen include the rewrapping of all pipelines, that it must re-pig all pipelines by December 2006, and that all mitred bends must be removed by the end of this year to facilitate pigging. The report states that the current intervention plans at both refineries are in line with international best practice, that significant sections of the pipelines have already been cut out and repaired, and that all the recommendations, when implemented, will help to ensure the integrity of the pipelines in the future.
The international peer review of the report found no errors.
The overall judgement is that the Sapref and Engen pipelines do not need to be replaced provided the recommendations made by PPT are adhered to.
The next step
Sutcliffe says the city council has met with both Engen and Sapref which have accepted PPT’s findings and recommendations without any reser-vation.
“The city will ensure that all the recommend-ations of PPT are fully complied with and that the recommendations are incorporated into thescheduled trade permits of both Engen and Sapref. The city retains the services of PPT to review all inspection records on an annual basis, in order to provide expert opinion.
“The city is currently expanding the study to include the Island View complex, which has a number of pipelines and is faced with similarchallenges. We are also establishing a committee with all relevant role-players to deal with the right-of-way issues,” he explains.
Response from the refineries
Rowe says Sapref is committed to meeting the recommendations of the report – as a minimum.
“R6,5-million was immediately released for the redesign of the CP system. British Pipeline Association has been contracted for this work. In addition, we will continue with the present pipeline inspection programme that exceeds US standards for a few years after completion of the upgrade and we will share inform-ation on the pipelines such as operating temper-atures and inspection results with the community.
“We have also commissioned an integrity review of our pipelines within the Island View complex.” Adherence to the report will cost Sapref R300-million to R400-million.
In a statement issued shortly after the report was published, acting GM for the Engen refinery Willem Oosthuizen said it believed “that the results of the PPT study . . . are accurate”.
“The study . . . pointed out that the cathodic protection system of our pipelines has fallen behind international best practice and it needs immediate upgrade. As a result of this finding, an international company is now doing a design that will assist us in upgrading our cathodic protection to be in line with international best practice.” He also said that his refinery had spent R20-million on repair work to date, and estimated that another R50-million to R60-million will beneeded to complete the remaining repair andupgrading work.
Community demands new pipelines
The South Durban Community Environmental Alliance (SDCEA) is a fierce Green voice. In its attempts to be heard SDCEA chairperson Desmond D’Sa had travelled to the UK in 2002 to confront the board of Shell – armed with nothing but a single share in the multinational company – on whathe terms the poor environmental standards the company upholds at its Durban refinery.
D’Sa tells Engineering News that because of the number of incidents in the last few years his organisation is “calling for the replacement of the pipelines, which have not been maintained properly”.
He says SDCEA is currently sourcing expert opinions of its own on the matter.
“The refineries should sit down and discuss with us the replacement of the pipelines, which are simply too old to continue operation”. However, Sapref and Engen are unlikely to relent.
Rowe says the PPT study ‘concluded that the pipelines did not need to be replaced.
“Their report was peer reviewed by a pipeline consultant who concurred with PPT’s findings and recommendations. These specialists would have recommended the pipelines be replaced if they felt this was necessary.
“We have been advised that, once the recommendations have been implemented, the lines will last at least another 40 years.” In Engen’s statement Oosthuizen says the study’s results “have confirmed that our pipelines do not need to be replaced. The programme we have in place will ensure that the long-term integrity of our pipelines is maintained”.
Edited by: Irma Venter