Flexcrete secures major pipeline project

Citation

(2002), "Flexcrete secures major pipeline project", Anti-Corrosion Methods and Materials, Vol. 49 No. 4. https://doi.org/10.1108/acmm.2002.12849dab.010

Flexcrete secures major pipeline project

Flexcrete secures major pipeline project

Cemprotec E942 (Plate 2), a state-of-the-art, cementitious and epoxy modified, anti-corrosion coating manufactured by Flexcrete Limited, is currently being used to protect almost 25km of steel gas pipeline running through Venezuela. The product was specified by Petróleos de Venezuela S.A. (PDVSA), said to be the world's second largest energy company, which operates one of the biggest installations globally to separate oil from gas.

PDVSA selected Cemprotec E942 for application to the 28in diameter pipeline – totalling a surface area of over 48,000m² – following technical assessments on a number of coatings by Intevep S.A., the PDVSA-owned research and testing authority, to determine whether they could withstand the most demanding exposure conditions. Cemprotec E942 was approved, having successfully completed the rigorous tests for the evaluation of performance characteristics such as adhesion to steel, cathodic disbandment and resistance to chloride ions.

Plate 2 A section of the steel gas pipeline in Venezuela, which is being coated with Cemprotec E942

The pipeline, which forms the principal artery for the wells of Eastern Venezuela, extends from the city of Anaco to Santa Barbara, crossing under roads and river-beds, which means that a significant section of the pipeline is flooded during Venezuela's rainy season. It carries 300 million ft³ of gas per day at a pressure of 1,200psi and at the end of its journey the gas is used in gas lift operations in the oil fields to optimise the flow from the wells. The pipeline was originally coated with fusion-bonded epoxy (FBE), but this, we are informed, had degraded to varying degrees on exposure to UV light. In some areas the coating was still soundly adhered, while in other areas it had totally degraded, leaving the steel unprotected.

The specification criteria demanded that the chosen coating should be self-priming, able to adhere to both any remaining FBE and bare steel and be capable of tolerating severe mechanical abuse, as, once the pipeline is fully coated, it will be buried to enhance the environment and minimise the risk of damage. In addition, the coating had to be compatible with cathodic protection systems and be capable of resisting disbandment under the applied voltage protection both to ASTM norms and to the more onerous PDVSA-modified ASTM high temperature norms.

In terms of application, it was important that the coating was both easy and quick to apply in the field and able to tolerate very hot, humid conditions without deterioration. The client also specified that the coating had to be environmentally friendly and exhibit a low toxicity risk.

According to Flexcrete the tests carried out determined that Cemprotec E942 complied with, and indeed surpassed, the coatings specifications of PDVSA. In fact, cathodic disbandment tests were initially carried out at room temperature and at high temperature (65°C) respectively. It is reported that, in view of the excellent performance of Cemprotec E942 under these conditions, the material was subsequently successfully evaluated at a more onerous temperature of 95°C. With regard to the impact resistance test, which evaluates the ability of a coating to resist any mechanical impact damage during installation and service of the structure, the results were reportedly excellent and superior to the impact resistance values presented by multi-layer systems. Following assessment tests of Cemprotec E942 over steel, Intevep S.A. also tested and approved the product over FBE at 95°C.

The contract of works was put out to tender by PDVSA and the contract was secured by specialist contractor Antonio Rocchetta y Cia S.A. Following successful completion of the testing, Flexcrete's exclusive distributor, Inversiones Juirica C.A., supplied Cemprotec E942 for application to the pipeline. A total of 110,000kg of Cemprotec E942 will be used, supported by a 20-year guarantee.

The properties claimed of Cemprotec E942, which were of particular benefit in this project, were its water-based, stand-alone formulation and its excellent bond to both steel and FBE. E942's high alkalinity immediately passivates steel surfaces and it is tolerant of minimal surface preparation; provided that there are no loose oxides on the surface, E942 will bond to and passivate steel. It also claims excellent mechanical properties, high compressive strength and abrasion resistance and provides an effective barrier to chloride ions. The reported ability of the product to withstand application in very high atmospheric temperatures and high humidity was also critical in this project, due to Venezuela's climate.

Details available from: Flexcrete Limited. Tel: +44 (0)1772 255024; Fax: +44 (0)1772 882016; E-mail: Ish@tflexcrete.co.uk