The purpose of the mechanical cleaning procedure is to remove any residual hydrocarbon and corroded scale from the internal pipeline wall.

Asilia Geo designed and purpose-built launcher traps, receiver traps and acceleration / deceleration spools are attached to the client’s pipeline ends. These traps accommodate the launching and receiving of the pipeline scraper tool (medium to heavy duty brush pigs) batches.

Asilia Geo uses progressive pipeline scraper tools to remove corroded scale. Specially designed brush scrapers are pushed through the pipeline by means of particulate and oil free compressed air.

These multistage batches are sampled and analysed for solids content and hydrocarbons. The successive batches of heavy-duty internal pipeline mechanical cleaning will stop at a predetermined internal pipeline surface cleanliness level and the process will move forward to the chemical cleaning phase.

The purpose of the chemical cleaning phase is to remove further corrosion and to reach an internal wall cleanliness level with a near white (NACE 2.0) metal finish.

The internal pipeline wall near white metal finish is achieved by batching inhibited acid slugs between two purpose-built pipeline scraper tools. The batch wall time contact of the inhibited acid cleaning batch ensures an internal pipeline wall that is totally corrosion free.

Every inhibited acid batch prior to launching pipeline end and at the receiving pipeline end is sampled and analysed. The inhibited acid batches are assessed for solids and titrated to monitor the chemical cleaning effectiveness. After successive batch runs and only when the inhibited acid batch shows no depletion in strength, is the pipeline considered clean.

The pipeline is visually inspected at predetermined points for verification and total internal pipeline wall cleanliness. Inspection points can be at manifolds, Tees, and the utilisation of camera crawlers and at spools.

Once the predetermined internal wall surface level of cleanliness (near white metal finish) has been achieved, the internal pipeline wall undergoes passivation to prevent surface wall oxidation and to prepare it for the coating process.

To create the predetermined pH required on the internal pipeline wall surface, inhibited water batches are run through the pipeline. The batches are sampled and analysed as well as the internal pipeline wall surface.

A solvent batch is run through the pipeline to effectively remove any internal pipeline wall surface moisture. The cleaned internal pipeline wall surface is then dried with dehydrated particulate free air and is ready for the coating application.

The epoxy coating is chosen with the client’s pipeline product requirements in mind.

The internal epoxy lining is made up of the base material and a catalyst. The epoxy coating manufacturer determines the pot life for enabling time extensions in safely performing the coating application.

The epoxy coating base and hardener is prepared by mixing them together with a pneumatic agitator and loaded into the pipeline as a homogenous batch between two specially designed Poly Urethane coating applicator scraper tools (Asilia Geo coating pig applicators).

Between each epoxy coat application, dry particulate free is pumped from the launch end of the pipeline to the receiver pipeline end to ensure the entrained epoxy coatings solvents evaporation.

On completion of the internal pipeline epoxy coating applications the Dry Film Thickness (DFT) is assessed at pre-determined inspection points on the pipeline. Asilia Geo uses epoxy application industry proven DFT methods during the coating evaluation and inspection.