Solvent recovery at a fine-chemical plant
The customer
A specialty chemical plant producing fine-chemical intermediates. The reactor offgas contains a mix of toluene, ethyl acetate and methanol vapor — aggressive solvents that destroy oil-sealed pumps within weeks.
The challenge
The previous oil-sealed pump was failing every 3–4 weeks. Each failure caused an unplanned shutdown of the recovery train, and cleanup of solvent-contaminated oil was a hazardous-waste headache.
The solution
An LS Series liquid-ring vacuum pump, configured to run with the same solvent (toluene) as service liquid in a closed loop:
- Solvent vapor is absorbed directly into the ring liquid
- A heat exchanger condenses the vapor; recovered solvent goes back into the process
- The pump itself never sees a phase change in the working chamber — no oil to contaminate, no vanes to dissolve
The result
- Pump life: 3 weeks → 2+ years and counting
- 100% of recovered solvent routed back to process (was: 0% — old pump oil was waste)
- Zero unplanned shutdowns in 14 months
- Hazardous-waste oil disposal eliminated