Trelleborg is a leader in thermal insulation for subsea installations in the Oil & Gas sector. They earned this position through innovation and product leadership. Norner is now engaged in a new exciting project. 

Thermal insulation is necessary to avoid formation of hydrate plugs and wax build-up in subsea structures. The build-up begins when the oil or gas composition temperature is not maintained and begins to cool. Without thermal insulation the cold seawater rapidly cools down the oil, forming hydrate or wax blockages making it impossible for a safe flow.The target of this new project is to develop a monolithic subsea thermal insulation material which vulcanises at temperatures below 50 °C and a low thermal conductivity of maximum 0.15Wm-1K-1. It also shall have unlimited water depth and high temperature operational capability.There are many materials that can be considered for this purpose. However, the raw material cost and ease and speed of application must be borne in mind. The material development programme started with a wide material focus and have looked at liquid systems such as methacrylate’s and also derivatisation of other commercially existing products to give new material possibilities. These considerations have led to the choice of rubber based systems as the main avenue of development. This also gives a very good fit to Trelleborg’s long experience with rubber based systems for commercial use.The development of a commercial product, also requires the development of suitable QC methods to allow inspection of the system during production. A wide range of non-destructive test methods have been investigated with a view to monitor the curing process on-line.The development of a rubber based product requires attention to both the resin and vulcanisation package. Several materials will cope with the temperature requirement, but not the requirements for low temperature vulcanisation or low thermal conductivity. Thus, considerable effort has been invested in the development of novel vulcanisation chemistries which are stable and which give the desired reaction at the required temperature. 

The situation is particularly challenging in as much as the ambient temperature where the material is to be applied is often close to the vulcanisation temperature and the applicator needs a certain minimum time to apply. The delivery of material to the point of use is also a consideration as the system must be stable for a long period of time from manufacture and through shipping to distant lands. Preferably without the need for refrigeration. Finally, the method of producing the material must be such that during work at site, using simple and robust equipment must be possible. 

Over the past two and a half years, the development has given us:

A clear decision as to which materials are suitable for this application.A developed formulation for a vulcanisable rubber system which fulfils the thermal and mechanical requirements.A 2-component system that is stable for transport.A self-agglomerating material, with excellent properties for application.A material that can be produced using relatively simple equipment.A good overview of relevant inspection techniques together with their readiness for use.

The current status is that the project is moving toward full-scale trials on production scale equipment in which the material will be produced and applied under conditions in keeping with typical production conditions. This will provide test items that can be subjected to full scale simulated service testing and material ageing and characterisation studies. This, with a view to releasing the application of this material as a robust service to the offshore oil and gas industry. 

Norner project contribution

Norner was selected as a partner due to our capacity in material development, polymer and polymer stabilisation competence backed up with a unique and advanced test facility. Our autoclave test house is fully utilised in this project to secure service life design in harsh environment as high temperature and pressure. Norner will further contribute with material characterization, develop non-destructive test methods (NDT), on-line curing methods and testing of the selected rubber material(s). NDT will be used for process and product quality control and verification. Novel destructive and non-destructive test methods are being developed in the project. This project increase Norner’s rubber material expertise, strengthen our competitiveness as a research institute and broaden our service offering as a material expert for the Energy Sector.