Abstract
This research present case study of sulphate scales found at water treatment unit, cooling water system and heat exchangers at Sidi Kerir Petrochemical Company Alexandria, Egypt, which declined overall production by 6%, about 250 million US. Dollar in losses 2018 due to unit's shutdown and flow restriction in pipelines. We tried many techniques like mechanical jet blasting using high-pressure water to crack the scale but it was a time-consuming root and need special equipment and large labour although it was not that efficient in areas with heat exposure and it cannot reach some areas. So we moved to next root for removing scales by chemical cleaning based on inorganic acid like hydrochloric acid, sulphuric acid,,, etc. although it can dissolve the scale in very limit efficiency but we didn't accept this method because those chemicals were very corrosive to metal surface like cast iron and stainless steel grade 304/316 also using those chemical present hard handling problem for adding or dilution. Therefore, we had to take the challenge to develop our new chemical cleaning methodology that combines between efficiency and safety. In new methodology, we developed new chemical formula based on mild organic acid mixture combined with sequencing agent, anti-re-deposition agent, wetting agent and pickling agent to chemically dissolve the scale in efficient and safe way.
The chemical cleaning technique was successful to dissolve the scale in very short time and in safe way to metal surface like cast iron and stainless steel. This invention is useful for the removal of sulphate scale like iron sulphate, calcium sulphate, barium sulphate and strontium sulphate from process equipment including pipes, pumps and storage tanks. It is also can be used to the removal of these scale deposits from other equipment such as boilers and heat exchangers.
