INTRODUCTION
Dorf Ketal, a company specializing in the development of chemical solutions for various industrial sectors, successfully conducted a corrosion-control project in the crude distillation unit (CDU) of a refinery located on the southern coast of India. This case study demonstrates the effectiveness of a GUARDIAN SR Series corrosion inhibitor in mitigating corrosion in the unit’s overhead lines, outperforming the results previously achieved with competitor products.
REFINERY OPERATIONAL CONTEXT
The crude distillation unit featured a two-stage condensation system in the CDU overhead line. One stage was designed for cold reflux, and the other was designed for hot reflux. Under these operating conditions, corrosion control was a critical factor in ensuring the safe and efficient operation of the unit.
Before Dorf Ketal’s intervention, the refinery was using a competitor’s product at dosage levels ranging from 5 to 6 ppm. However, even at these relatively high dosages, the iron concentration in the boot water frequently exceeded 1 ppm, indicating insufficient corrosion protection. These excursions occurred, on average, three times per week, adversely affecting operational performance and increasing maintenance costs.
DORF KETAL’S PROPOSED SOLUTION
To address the issue, Dorf Ketal proposed replacing the competitor’s product with its proprietary GUARDIAN SR Series inhibitor, an oil-soluble, stearic, film-forming amine with superior film-forming properties. This product is particularly effective in corrosive environments characterized by the presence of HCl, H₂S, and SOₓ — conditions commonly found in the overhead lines of crude distillation units.
The refinery approved Dorf Ketal’s proposal and agreed to conduct a trial using the GUARDIAN SR Series corrosion inhibitor, with the following success criteria:
- Continuous maintenance of iron content in the boot water below 1 ppm;
- Reduction of the corrosion inhibitor dosage to less than 5 ppm.
IMPLEMENTATION AND RESULTS
The product was prediluted in kerosene and injected into the overhead line upstream of the fin-fan coolers. The product’s performance exceeded expectations:
- Iron content in the boot water was consistently maintained below 1 ppm throughout the trial period;
- Product dosage was reduced to 2–3 ppm, significantly lower than the dosage required with the previous product.
This performance represented the best result ever achieved by the refinery with any chemical treatment program. The effective corrosion protection, combined with reduced product consumption, demonstrated the technical and economic superiority of Dorf Ketal’s solution.
RETURN ON INVESTMENT (ROI) AND EXPANDED APPLICATION
The adoption of the GUARDIAN SR Series corrosion inhibitor significantly improved the operational reliability of the unit while substantially reducing chemical costs. Based on these positive results, the refinery decided to extend the use of the inhibitor to other critical units, including the visbreaker and the diesel hydrodesulfurization unit.
In recognition of its outstanding performance, Dorf Ketal was awarded an annual supply contract for continuous product delivery. Since then, the product has been successfully applied at the refinery for more than six consecutive years, reaffirming its technical and commercial value.
