Thermal Insulation for Pipelines, Risers, Spools and Subsea Structures
Why apply Thermal Insulation Coatings?
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Assets such as offshore pipelines, risers, spools and subsea structures which transport liquid products may be required to maintain a minimum temperature while the product is being transported within the asset, particularly offshore. Some liquids such as oil and gas can leave wax or hydrate deposits if a minimum temperature is not maintained. These deposits can, over time, build up and block the asset/pipeline either reducing or completely stopping flow/production. External wet insulation can be designed and applied to ensure the reduction in product temperature is kept within a range so the risk of deposits during production is acceptable. Insulation can also reduce the frequency of pigging operations during the life of the asset.
During other operational events, such as pipeline shutdowns, the product is contained in a stationary state within the asset/pipeline while the process facility has other operations performed. Similarly, to avoid deposits during these shutdown periods external insulation can be designed and applied to ensure the reduction in product temperature is kept within a range so the risk of deposits during shutdowns is acceptable.
The cycle time to apply and cure the wet insulation coating for offshore assets, particularly field joints on spoolbases and onboard S lay or J lay vessels is critical. To achieve the fastest and reliable cycle times, training of the OJS application crew, formulation of material properties (particularly curing time) and the design of equipment is essential.
OJS provides two types of wet Thermal Insulation Coating Services;
- Injected Molded Solid Polyurethane Application (IMPU)
- Injection Molded Polypropylene Application (IMPP)
IMPU
Injected Molded Polyurethane Applications provide thermal insulation and are commonly used offshore on flowline and riser field joints, spools and subsea structures. It is used less often onshore to thermally insulate pipelines and spools. The asset will require to have been pre-coated with an anti-corrosion layer prior to the thermal insulation application.
The preparation for IMPU requires that the anti-corrosion layer is in good condition and the bevel faces of the parent coating (usually PP) are cleaned, abraded and then pre-heated to build bond strength between the PP and IMPU. Once this preparation is completed a mold is placed over the area to be treated and Solid Polyurethane is injected into the annulus and often overlapping the parent coating bevel faces and onto the OD surface of the PP. Once the material cures the mold is removed and inspected.
OJS can apply all Solid Polyurethanes available on the market however we recommend our own formulated solid polyurethane material called Densiflex for IMPU coatings. Densiflex is mercury free and fast curing – which is suitable for the offshore market.
IMPP
Injected Molded Polypropylene Applications provide thermal insulation on pipeline and riser field joints and spools. The asset will require to have been pre-coated with an anti-corrosion layer prior to this thermal insulation application.
The preparation for IMPP requires that the anti-corrosion layer is in good condition and the bevel faces of the parent coating (usually PP) are cleaned, abraded and then pre-heated to build bond strength between the PP and IMPP. Once this preparation is completed a mold is placed over the area to be treated and Solid Polypropylene is injected into the annulus. Once the material cures the mold is removed and inspected.
OJS offers IMPP in co-operation with Bredero. OJS applies the FBE and CMPP layers and Bredero inject the PP.
Densiflex®, Sea Sleeve®, and Deep Sea Sleeve® are registered trademarks of Offshore Joint Services, Inc.
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