In petrochemical complexes, various waste streams are generated, many of which contain organic acids requiring further treatment before discharge to the site outlet or the Effluent Treatment Plant (ETP). However, with the right separation technology, these streams can be transformed from waste into a valuable recoverable resource.
A major petrochemical complex in Turkey partnered with ESMIL Group to develop an advanced membrane-based solution for the recovery and concentration of organic acid. Working closely with the main process licensor, ESMIL delivered a reliable, long-term solution designed for consistent performance under demanding operating conditions.
Design Assumptions and Project Scope
ESMILGroup was tasked with delivering a solution meeting clearly defined performance and engineering.
- Minimum 90% hydraulic recovery
- Minimum 80% acid recovery
- Robust, modular, and fully automated installation
- Equipment designed in accordance with Oil & Gas engineering specifications
- Suitable for ATEX Hazardous Zone 2 environments
Comprehensive Process Analysis
Every ESMIL project begins with a detailed understanding of the upstream process and feed characteristics. For this application, the development phase consisted of two key stages:
1) Testing of the process medium at ESMIL’s High Wycombe facility to verify initial design assumptions and membrane compatibility.
2) Extended trials using industrial-scale membrane modules operated under near-real conditions to validate performance and optimise operating parameters.
This structured approach minimises design risk, ensures accurate data collection, and enables precise system optimisation tailored to the feed composition.
Extended Membrane Performance Testing
Given the presence of concentrated organic acid, additional membrane durability and performance assessments were conducted, including:
- the impact of the acidic environment on membrane module materials,
- impact on acid rejection and permeate flux characteristics after prolonged exposure to concentrated medium,
- cleaning requirements under long-term operating conditions.
Process Description
A 60m3/h system is provided, but ESMIL have experience of system ranges from 5 to 150 m3/h to suit customer requirements.
The feed stream contained 1-2% organic acid. To enhance separation efficiency, the feed was cooled to below 20°C before entering to the first membrane stage.
The operating pressure varies up to 60 barg depending on the feed acid concentration. For the design condition feed specification, the pressure is around 45 barg.
First Stage
In this stage, the majority separation takes place. The recovered concentrated acid stream is sent to the main process plant.
Second Stage
The permeate from the first stage, still containing residual acid, is sent to a second stage to maximise overall recovery. The concentrate from the second stage was recycled to the feed tank of the first stage, while the final treated water stream is discharged to the site effluent treatment plant. This two-stage configuration ensures optimal acid recovery while maintaining high hydraulic efficiency.
Results from the Site
The plant has achieved the target design parameters. Total acid recovery exceeds 82%, while hydraulic recovery is maintained at 85–90%.
Detailed operational data are presented in the table below:
| Parameters | Unit | Pass-I | Pass-II |
|---|---|---|---|
| Capacity | T/h | 60 | 54 |
| Temperature | °C | < 20 | < 20 |
| Operating Pressure | Barg | 50 | 40 |
| Acid Inlet | % | 1.5 – 2% | < 0.7 - 1 |
| Acid Recovery | % | > 82% | > 82% |
| Hydraulic Recovery | % | 85-90% | 85-90% |
| Cleaning Frequency | Weeks | 6 | 13 |
Summary
This project demonstrates the way ESMIL Group methodology for complex industrial applications:
- Thorough understanding of the upstream process and feed characteristics
- Laboratory validation and pilot-scale trials
- Careful engineering design aligned with Oil & Gas standards
- Delivery of a fully integrated, automated membrane solution
The result is a reliable, ATEX-compliant membrane unit tailored to the plant’s operational objectives – converting a waste stream into a valuable resource while ensuring safe operation in demanding O&G environments.
