EZ-CAUSTIC®
On-line Monitoring of Caustic Scrubbers - Ethylene production
In the petrochemical industry ethylene is produced by steam cracking. Impurities in the cracking gas, such as Carbon dioxide (CO2) and Hydrogen sulfide (H2S), are washed out from the gas phase in the caustic scrubber (wash tower). Sodium carbonate (Na2CO3) and sulfide (Na2S) result from the reaction with excess NaoH.
The effectiveness of the scrubber liquor in removing impurities depends upon the concentration of the scrubbing chemical, which is continuously depleted during scrubber operation. Operation can only be efficient when the concentration of the scrubbing chemical is maintained. Therefore the outlet of the caustic scrubber is controlled at ± 3% NaOH overshoot, usually analyzed by off-line laboratory measurements.
The heart of the EZ-CAUSTIC® On-line analyzer system consists of appropriate wet-chemical technology for lowering effectively the scrubber set point. AppliTek designs the analyzer system in accordance to your specific needs, including a special sample preconditioning system specifically built to withstand the harsh scrubber conditions. References: the unique analyzer system has been used for more than 18 years in ethylene plants.
Operational benefits
- Lower NaOH consumption by allowing operation at lower caustic concentration
- Lower set point: typically only ± 0.5% NaOH overshoot
- Up-time exceeding 97%
Purpose-built sample preconditioning
- Pressure up to 40 bar
- Temperature up to 120°C
- Protection EexIICT5 conform CENELEC
- PLC controlled for safety
- Degassing process controlled by pressure indicator alarms
- Product recognition by 2 conductivity sensors
- Fail safe design
- Sample cycle of the on-line analyzer protected by safety benchmarks
Product list for caustic scrubbers:
UPA® Universal Process Analyzer
State of the art multiparameter analyzer platform enabling you to monitor precisely critical process parameters. Theoretically the UPA® Universal Process Analyzer can sample and analyze up to 8 individual streams...
For more information on this systems, please check the following section:
» Go to Analyzers / Wet-chemical process analyzers