A chemical flush is a process where pressure is applied to empty a pipeline using appropriate chemicals to suspend, disperse and remove accumulated materials. After this process, the pipelines are given a final flush with clean water and chemical inhibitors are added to protect the pipelines.

The reason why chemical flushing is been used today is to remove all dirts , debris, oil, grease, rust, scale, slug, that could be found or formed in the pipelines. These deposits or sometime called fouling, needs to be removed time to time to prevent damage and maintain efficiency of operation .During chemical flushing thin layer of surface of pipe wall will remove as well  as all the unnecessary contamination. Chemical cleaning is preferably used compared to the oil flushing because, chemical flushing will reduce the oil flushing cost in term of flushing time and number of oil flushing materials use such filter elements.

The usual chemical flushing involves

  • Liquid drain opener (alkaline) as first degreaser to remove grease, oils and fat, alkaline opener also dissolves organic residue and cleaning where harder deposits have occurred.
  •  Following this is the liquid drain opener (acid) as second, for neutralizing the caustic remaining on the surfaces of the plant or removing scale build-up. The acidic opener removes mineral deposits in the equipment (especially warm or hot fluid lines).
  •  Rust and scale remover which is used in all operations where rust should be removed and avoided to lengthen pipelines life, efficiency and improve looks of metal pipeline,
  • Neutralization as third stage, rinsing of the pipeline with demineralized water
  • Corrosion inhibitor as final stage. 

During this process temperature and chemical pH level must be carefully monitor and control in order to complete the process with high quality result. Small mistake will cause a lot of problem where the whole process may need to carry out again which not only cost money but time consuming.

Any pipeline, regardless of diameter, requires a large volume of chemicals to be filled and circulated with, to achieve desired results. Special attention has to be paid to the velocity and volume calculations during the pre-engineering phase.

Ruth Ozichu Yakubu

Production Chemist

Epoxy Oilserv Limited


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