Why buyers confuse these two
In ethanol extraction lines, “tank” can mean many things. Two vessels are often mixed up:
- Extraction tank: where solvent contacts solids to pull compounds out
- Ethanol recovery vessel: where condensed ethanol is collected (or stored) during recovery/reuse
If you don’t separate these roles clearly, suppliers may quote the wrong vessel type, wrong ports, or wrong design pressure—and your line bottlenecks later.
If you want the full process map: botanical extraction process
1) Roles: What each vessel actually does
1.1 Extraction tank (process vessel)
Main duties:
- solids loading and wetting
- mixing/suspension
- heating/cooling for extraction kinetics
- (optional) reflux operation for heated ethanol
- transfer to separation/concentration
What defines it:
- agitator duty + jacket duty + ports/manways + drainability
1.2 Ethanol recovery vessel (receiver / storage)
Main duties:
- collect condensed ethanol from recovery condenser
- buffer ethanol for reuse (stabilize supply to extraction)
- allow phase settling if water content varies (process dependent)
- enable safe venting and level control
What defines it:
- receiver volume, level control, vent/relief philosophy, and safe connections—more than agitation.
2) When you need a dedicated ethanol recovery vessel
You almost always need a dedicated recovery vessel when:
- you remove ethanol during concentration/recovery (condensation occurs)
- you want to reuse ethanol (storage/buffer needed)
- you run continuous or multi-batch operation and need stable ethanol supply
- you need to isolate “dirty recovery” vs “clean reuse” streams (quality control)
If you’re planning recovery as a module, see: solvent recovery system for ethanol extraction
3) Interfaces: How these vessels connect (and where designs fail)
3.1 Extraction tank interfaces (common)
- solids charging (manway/hopper)
- vapor outlet to reflux condenser (if heated near boiling)
- bottom drain to transfer pump / filter
- sampling ports and sight glass
- CIP connections (if required)
A dedicated interface guide: reflux condenser interface specification
3.2 Recovery vessel interfaces (common)
- condenser outlet (condensate inlet)
- vent line (to safe vent / recovery / charcoal / site system—site dependent)
- level measurement and high-high alarm
- drain/transfer outlet to ethanol storage or reuse feed
- optional sampling point for ethanol quality (water content/contamination)
Common failure: recovery vessel venting is not defined, leading to odor complaints or unsafe vapor release.
If odor and solvent loss are concerns, read: cooling and solvent loss control
4) Sizing Notes: How buyers should think (without fake precision)
4.1 Extraction tank sizing is driven by batch recipe
Extraction tank is sized by:
- solids per batch (kg)
- solid–liquid ratio (L/kg)
- working volume + headspace (foam/reflux)
- mixing and viscosity behavior
Sizing fundamentals: extraction tank sizing
4.2 Recovery vessel sizing is driven by condensation rate + buffering
Recovery vessel is sized by:
- expected condensation rate (L/h)
- maximum transient surges (startup, reflux bursts, vacuum changes)
- desired buffer capacity (how long you can run without transfer)
- safe working level range (avoid carryover into vent)
Buyer rule: Don’t size the recovery vessel only by “daily recovered ethanol.” Size it by:
- peak recovery rate and
- how often you plan to empty/transfer it.
4.3 One-vessel vs two-vessel recovery (common options)
- Single receiver: simplest, lower CAPEX
- Two receivers (dirty/clean or stage separation): better control of ethanol quality and batch-to-batch consistency, higher CAPEX
Choose based on:
- reuse quality requirements
- multi-product cross-contamination risk
- whether you recover mixed ethanol-water and need settling/management
5) Design differences that affect cost (what buyers should not miss)
1. Extraction tank cost drivers (high impact)
- agitator torque/shaft seal
- jacket duty and type
- ports, manway, CIP readiness
- vapor-tight design if closed/reflux mode
- safety scope (EX, interlocks)
2. Recovery vessel cost drivers (high impact)
- vent/relief philosophy and vapor-tight requirements
- level measurement and alarms
- grounding/bonding provisions
- connection standards and drainability
- material and finish (less often extreme than extraction tank, unless QA requires)
A broader view of tank cost drivers: extraction tank cost drivers
6) Safety and EX scope: Recovery vessel is often forgotten
Recovery vessels often sit near condensers and may see:
- warm ethanol
- vapor traces at vents
- transfer operations to storage
So even if the extraction tank is in one area, recovery vessel placement may create a different hazard boundary.
If you’re defining EX scope efficiently: EX scope for ethanol extraction
7) RFQ Copy/Paste (so suppliers quote the right thing)
7.1 Extraction tank (RFQ line)
“Provide an agitated extraction tank for ethanol extraction. Basis: solids ___ kg/batch, S/L ratio ___ L/kg, temp ___°C, viscosity notes ___. Include working volume + headspace definition and required interfaces.”
7.2 Ethanol recovery vessel (RFQ line)
“Provide an ethanol recovery receiver to collect condenser output. Basis: peak recovery rate ___ L/h, expected surge ___, buffer time ___ min/hours, venting philosophy ___, level measurement + high-high alarm. Include drain/transfer interface to reuse/storage.”
7.3 If you want a turnkey quote
Use your full checklist: herbal extraction line quotation checklist
FAQ (with answers)
1. Can the extraction tank also act as the ethanol recovery vessel?
Usually no. The extraction tank’s job is solids contact and mixing; the recovery vessel’s job is to safely collect condensate and buffer reuse. Combining roles creates operational and safety compromises.
2. What is the most common design mistake for recovery vessels?
Undefined venting/relief and undersized buffer capacity, leading to odor, solvent loss, or level carryover into vents.
3. How do I know my recovery vessel is undersized?
Symptoms include frequent overfill alarms, need to stop recovery to transfer ethanol, unstable condenser performance, or ethanol carryover into vent lines.
4. Do I need a recovery vessel if I’m not reusing ethanol?
If you condense ethanol (for disposal or collection), you still need a receiver/collection vessel—reuse just increases the importance of buffer sizing and quality control.
5. What determines whether I need one receiver or two?
Reuse quality requirements, cross-contamination risk, and whether you need to separate “dirty early condensate” from “clean stable condensate.”
Need help defining recovery vessel scope and sizing basis?
Send your batch size, recovery method (vacuum concentration or other), expected recovery rate, and reuse requirements. We’ll recommend receiver role, interfaces, and sizing notes.