Choose a Herbal Extraction Machine by Throughput (kg/h)
If you start with “I need X kg/h,” you’ll get better quotes than starting with “I need a 1000 L tank.” But kg/h only works when you tie it to batch rhythm and the slowest step in your line.
Below is a practical way to choose the right extraction setup without getting sold an oversized tank (or a fast extractor that just shifts the bottleneck).
What does “kg/h” actually mean for herbal extraction?
Before anything else, decide what your kg/h refers to:
- kg/h of raw herb in (wet or dry basis?)
- kg/h of extract out (liquid, paste, or powder?)
- kg/h of finished product (after concentration/drying?)
Most equipment sizing uses kg/h of raw material (dry basis) + your batches per hour/day.
Use process workflow map to keep the whole line consistent (extraction → separation → concentration → recovery).
How to convert your kg/h into batch size
Most herbal extraction is still batch-based at industrial scale. So we convert:
- Throughput target (kg/h) × operating hours/day = kg/day
- kg/day ÷ batches/day = kg/batch
Example:
- target: 50 kg/h
- run: 10 h/day → 500 kg/day
- plan: 2 batches/day → 250 kg/batch
That “kg/batch” becomes the real sizing basis.
Then you choose:
- solvent amount per batch
- extraction tank working volume
- filtration capacity per batch
- concentration/recovery capacity per batch
How to choose solvent and S/L ratio (because it sets tank volume)
1. How to set ethanol–water blend (if ethanol is allowed)
Solvent choice changes selectivity, viscosity, and recovery load. Use ethanol–water ratio guide as the quick decision tool.
2. How to set solid–liquid ratio (L/kg)
This number drives tank size more than anything else. Use solid–liquid ratio guide to choose a realistic range that still filters well.
Once you know:
- kg/batch
- L/kg (S/L ratio)
You can estimate solvent volume per batch:
- solvent (L) ≈ kg solids × (L/kg)
That gives a first-pass working volume target.
How to pick the extraction method that matches kg/h
Option A: Agitated extraction tank (most common)
This is the default for most herbal production because it scales and is flexible. Your kg/h is achieved by choosing the right extraction tank batch size and cycle time.
Option B: Add reflux setup (if heating ethanol near boiling)
If your process runs hot with ethanol, reflux keeps solvent ratio stable and prevents odor/solvent loss. That improves repeatability and often improves real throughput (less rework).
Option C: UAE (when you need shorter extraction time)
UAE can shorten extraction time, but only helps kg/h if filtration and recovery keep up.
What usually limits kg/h (it’s often not the extractor)
People buy a bigger extractor and still can’t hit kg/h because of one of these:
1. Filtration capacity
If filters blind, your line stops. So fix filtration clogging is very important for herbal extraction.
2. Concentration / solvent recovery capacity
If you’re making paste or need ethanol reuse, ethanol recovery often becomes the real bottleneck. A fast extractor just feeds a slow recovery skid.
A practical sizing workflow (what I’d do on a real project)
Step 1: Lock your batch rhythm
Pick a realistic plan:
- 1–3 batches/day for many plants (depends on extraction time + cleaning)
- define operating hours/day
Step 2: Lock kg/batch and solvent volume/batch
From kg/h → kg/day → kg/batch, then apply S/L ratio.
Step 3: Choose tank working volume and headspace
Headspace matters if:
- foaming is possible
- you run heated solvent
- you want stable vapor handling
Step 4: Check “can filtration finish within the batch window?”
If not, increase filtration capacity or change strategy (staged filtration, centrifuge option).
Step 5: Check “can recovery finish within the batch window?”
If not, your kg/h is fake. Increase evaporation/recovery capacity or change product plan.
Step 6: Add the right controls
Stable temperature, decent sampling points, and practical drain design reduce downtime more than most upgrades.
What to ask suppliers (so they don’t just quote a tank)
Send these 10 lines and you’ll get more meaningful quotes:
- Target throughput: ____ kg/h (dry basis), ____ h/day
- Planned batches/day: ____ → solids per batch: ____ kg
- Solvent system: water or ethanol–water; allowed ratio range ____
- S/L ratio: ____ L/kg (or ask supplier to propose)
- Temperature ceiling: ____ °C; heating method available ____
- Extraction time target: ____ h (or endpoint criteria)
- Separation target: ____ micron; throughput ____ L/h
- Final product: liquid / paste / powder
- If ethanol: recovery required yes/no; reuse yes/no
- Cleaning: manual or CIP-ready; changeovers per week ____
FAQ (with answers)
1. Can I really size a herbal extractor directly from kg/h?
Yes—but only if you translate kg/h into kg/batch and define batches/day. Otherwise it’s just a marketing number.
2. What’s the fastest way to increase kg/h without buying a huge tank?
Shorten the cycle time (heat-up, transfer, filtration) or add parallel tanks. Often fixing filtration/recovery gives more kg/h than “bigger extraction.”
3. UAE seems faster—will it increase kg/h?
Sometimes. But UAE often increases fines and can slow filtration. It helps only when the downstream is designed for it.
4. Why do quotes vary so much for the same kg/h?
Because suppliers assume different solvent ratios, cycle times, filtration scope, recovery scope, and automation/safety scope.