A Technical Primer on Hydrocarbon Extraction
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Every figure here comes from N.B. Oler design data, system specifications and in-house testing. No industry averages.
01. Why butane and propane
| Solvent | Boiling point at 1 atm | What it buys you |
|---|---|---|
| n-Butane | -1°C (30.2°F) | Higher cannabinoid pull, slower recovery, lower system pressure. The workhorse for shatter, budder and badder |
| Propane | -42°C (-43.6°F) | Lighter, more selective for terpenes, faster recovery, much higher system pressure. Used blended, rarely alone |
Most production runs a blend. Adding propane raises the vapor pressure of the mix, which speeds recovery and lifts terpene retention, and it raises the pressure your vessels see. That is why the blend ratio is an operating decision, not a recipe detail. Pressures by temperature and blend are in REF-VP-01 Vapor Pressure.
02. The envelope you are working inside
| Limit | Value |
|---|---|
| Vessel MAWP | 250 psi at 200°F (93°C) |
| Vessel MDMT | -155°F (-104°C) |
| Vessel hydrostatic test | 325 psi at 70°F (21°C) |
| Chilling jacket MAWP | 100 psi at 200°F (93°C) |
| Jacket hydrostatic test | 130 psi at 70°F (21°C) |
| System operating range | -65°C to 50°C (-85°F to 122°F) |
| Extraction pressure, typical | 0 to 30 psi |
| LCO2 injection line relief | 22 psi |
| Target vacuum before a run | -29.5 inHg |
Vessel figures per 3P Certz design calculation report DCR-200101-R1, 2019 ASME BPVC Section VIII Division 1. Operating range per N.B. Oler system specifications.
Extraction happens at low pressure. Typical soak and transfer pressures run 0 to 30 psi. The 250 psi MAWP is not a working pressure, it is headroom. If your process is sitting near 250 psi you have a problem, not a technique.
The operating range is narrower than the vessel rating. The vessel is designed to 200°F (93°C). The system is specified to 50°C (122°F). The lower number governs, because the limit is set by the softest component in the assembly, not by the shell.
03. What a run actually is
Recovery rate, not extraction rate, sets your cycle time. N.B. Oler runs 3/4 inch jacketed, chilled recovery lines that move 4 lb or more of solvent per minute.
- Chill the solvent. LCO2 or chiller fluid into the solvent tank jacket. Cold solvent means lower vapor pressure, so you can move it without fighting it.
- Load and chill the material columns. Cold biomass gives up less chlorophyll and less plant wax. Most of your product quality is decided here, before any solvent moves.
- Vacuum down to -29.5 inHg. Air is oxygen against your terpenes and a false pressure reading against your process. Hold ten minutes. Any decay is a leak, and a leak is a solvent release waiting to happen.
- Pressure test. Nitrogen in 10 psi steps, one step per minute, to 100 psi. Hold ten minutes. Soapy water on anything that drops.
- Bring the hot side up. The recovery vessel jacket drives solvent back out of solution. It cannot do that cold.
- Inject and soak. Soak time is a product decision. Short soaks pull terpenes and leave pigment. Long soaks pull more total mass, and more of what you will have to remediate later.
- Transfer. Straight to recovery, or through the de-wax vessel first if running in-line. In-line de-waxing at -30°C (-22°F) or colder adds 30 to 90 minutes and removes a separate winterization step downstream.
- Recover. Passive recovery through the molecular sieve back into the chilled solvent tank. No pump in the solvent path means nothing in the solvent path to rebuild.
04. Throughput, worked from real system capacity
| 20 LB system | 40 LB system | |
|---|---|---|
| Material columns | 2 x 6" x 48" | 4 x 6" x 48" |
| Dry material per run | 9,000 g (19.8 lb) | 18,000 g (39.6 lb) |
| Live resin per run | 16,329 g (36 lb) | Upgradeable to 72 lb (32.7 kg) |
| Run time | About 1 hour | About 1 hour |
| Rated throughput | 20 lb/hr | 40 lb/hr |
| Solvent MAQ design | 100 lb (45 kg) | 200 lb (91 kg) |
| LCO2 per run | About 75 L | 200 to 300 L |
| Heating | 208V/80A or 480V/40A | 24 to 48 kW at 100°F (38°C), 6 GPM |
One shift on a 20 LB system
Concentrate produced depends entirely on your input material. That is deliberate. Yield is a property of your biomass, not of the machine, and two operators on identical systems will report numbers far enough apart that any single published yield figure is misleading. Run your own material, record it, and use your own number.
Where the real ceiling is. Almost nobody is limited by extraction. At five 20 LB runs a shift you are producing faster than a typical vacuum oven bank can purge and faster than a hand packaging line can keep up. Count your oven capacity and packaging labor before you buy a bigger extractor.
05. Post-processing, in one page
| Output | What changes |
|---|---|
| Shatter | Stable, undisturbed vacuum purge. Long, low and left alone |
| Wax, badder, budder | Agitation during or after purge. Whipping nucleates the mass |
| Diamonds | Slow pressure decay in a sealed vessel over days to weeks, riding the saturation curve down with an adjustable relief. See Diamond Formation |
| Live resin | Fresh frozen input, cold throughout, minimum handling. The terpene fraction is the product |
| Crude | No selectivity applied. Feedstock for distillation or remediation |
Decarboxylation, for reference
| Temperature | What happens |
|---|---|
| Below 100°C (212°F) | Minimal, very slow |
| 100 to 120°C (212 to 248°F) | THCA conversion begins |
| 120 to 140°C (248 to 284°F) | Peak THCA to THC conversion |
| 140 to 160°C (284 to 320°F) | THC peak, highest yield |
| Above 160°C (320°F) | THC begins to degrade |
Well above the 50°C (122°F) system limit. Decarboxylation happens in dedicated equipment downstream, never in the extraction system.
06. The costs nobody quotes you
- C1D1 booth or room build-out. Up to 12 weeks lead time, and a significant capital line of its own.
- Bulk LCO2 storage tank. 16 or more weeks lead time. At 75 L per run on a 20 LB system, a dewar will not carry a production schedule.
- Low temperature chiller. 20 or more weeks lead time. It needs to reach -40°C (-40°F) at minimum for standard cold extraction. For live resin, plan on -60°C (-76°F) minimum and -70°C (-94°F) recommended. It draws 480VAC / 60Hz / 3Ph / 55A or more, and should live outside because its heat load will overwhelm your HVAC.
- Vacuum, heating and nitrogen. C1D1 rated vacuum pump at 2.8 CFM or greater, hot water recirculation at 208V/80A or 480V/40A, K-type nitrogen bottle regulated 15 to 100 psi.
- Post-processing. Vacuum ovens, cold storage, packaging.
Order the long lead items the day you order the system, not the day it ships. The extractor arriving before the booth is finished is the most common and most expensive scheduling mistake in this industry. Current lead times: Lead Times, Published. Full utility list: Site Requirements and Utilities.
Sources. N.B. Oler system specifications; N.B. Oler Hydrocarbon Operators Manual; N.B. Oler in-house testing; 3P Certz design calculation report DCR-200101-R1. No third party industry data is used.