PTQ Q3 2025 Issue

Figure 3 DSG reboiler fouling and corrosion

change subsequently caused emulsion concerns, leading to repercussions such as: • Impact on WO disposal system: Due to the increased loading of hydrocarbons caused by emulsion, there was a heightened demand for natural gas to facilitate combustion in the thermal oxidiser tank. This surge in hydrocarbons led to a rise in effluent generation in the tank farm, subse - quently resulting in escalated treatment costs. • Impact on QW and DSG system: An increase in emul - sion concerns at the QW system was observed (see Figure 2 ). As a result, there was an increased frequency of pre- filters, filters, and coalescer element replacements due to the underperformance caused by the accumulation of dirt on the filter elements. If no proper treatment is done upstream, DSG is adversely affected. This can result in reduced DSG reboiler perfor - mance due to fouling/under-deposit corrosion identified during inspection (see Figure 3 ), an increase in DSG blow- down requirements, and a higher demand for medium pressure (MP) steam to compensate for the decrease in dilution steam (DS) generation. • People and environmental exposure:³ Due to the increased presence of hydrocarbons, there arose safety concerns for the personnel involved in operations, particu - larly those responsible for tasks such as sample collection and maintenance. Process improvements Root cause analysis identified that the new WO had a density closer to water, leading to the issue of emulsion at the KOD and subsequent concerns in the water loop. To address these challenges, several operational improve - ments were implemented: • KOD draining procedure: It was established (see Figure 4 ) to better control turbidity and enhance the separation of streams directed to the QW loop, thereby reducing the impact on the DSG system. • Monitoring strategy: Daily sample testing of KOD sam - ples was initiated to monitor pH and turbidity levels, fur - ther helping to understand if the draining is sufficient or needs to be addressed. Additionally, dissolved oxygen (DO) testing was conducted on QW and DSG samples to ensure optimal operational conditions. • Procedures review: The cleaning and commissioning procedures for the DSG reboilers were thoroughly reviewed and modified to achieve improved outcomes in cleaning hard polymers and addressing corrosion issues effectively.

CGC at Braskem Idesa The plant encountered challenges in achieving the desired polytropic efficiency (PE) due to fouling concerns at the CGC. Root cause analysis (RCA) revealed that the wash oil (WO) quality being utilised did not meet the required standards (it had a low boiling point and higher density). This led to an increased demand for wash oil to enhance CGC efficiency. The desired characteristics for this oil are high aromaticity (preferentially higher than 90%), high ASTM D86 final boil - ing point (higher than 250°C), and low olefin content (bro - mine index lower than 1,000).2 Upon identifying this issue, the plant transitioned to a more suitable WO. M-factor [Ln(temperature ratio) / Ln (pressure ratio)] serves as a key indicator of compressor efficiency, unaffected by compositional effects. It tends to increase with fouling, indicating an inverse relationship with the polytropic efficiency (PE) of the compressor. The decrease in M-factor was evident after the change in wash oil quality. Impact of WO change Though improvements were observed at the CGC, this Figure 2 Quench water samples before and after emulsion at KOD

Hemispheric hood

Mist eliminator

T.I.

After draining procedure

I.D. 5100 mm

Vane type in let device

mini

155

440

205

HLCO

HLL

Vent hole

Hydrocarbon

Emulsion

Before draining procedure

Water

T.I.

Vortex breaker

Figure 4 KOD draining procedure

PTQ Q3 2025