Cannabis Extraction Heat Exchangers

Above the solvent vapor pressure at the warmest temperature the equipment could ever reach, not the temperature it normally runs. Propane is 175 psig at 100 F and about 225 psig at 120 F, which a shell left in the sun or a condenser with the chiller off can see, so 250 psig is the usual minimum design pressure on propane service and the relief valve is set at or below it and sized for the fire case. Butane is only about 37 psig at 100 F, which is why a condenser bought for butane and later run on a propane-heavy blend ends up rated below its contents. State the heaviest propane fraction the line will ever run on the inquiry and the rating follows from it.

Yes, as part of the technical report most codes now require for the whole extraction system. The International Fire Code chapter on plant extraction and NFPA 1 both call for a licensed engineer's report on the equiptment before the room is approved, and the exchangers are listed in it with the rest of the pressure equipment. The reviewer looks for the ASME data report, design pressure and temperature, the relief device and its set pressure, and the wetted material list for each unit. A report that stalls on one missing data report holds up the entire permit, so ask for the stamped data report and the material list with the quote, not after delivery.

With a relief device on every section that can be blocked in, on both sides of the tube wall. Liquid CO2 trapped between two closed valves and warmed toward room temperature passes its critical point at 88 F and 1,071 psia, and the pressure of a liquid-full system climbs steeply past that, so each isolable section gets its own relief. The utility side is the case skids miss: a tube failure in a CO2 heater or condenser puts CO2 at 600 to 5,000 psi into a water or glycol shell rated for 150, so the shell carries a rupture disk sized for a full tube break or is rated for the CO2 side. Relief lines are kept short and warm, because CO2 expanding below 75 psia forms dry ice that can block them.

Aluminum, brass and any elastomer the solvent swells or that cannot survive rapid depressurization. On propane and butane the gaskets are PTFE or a fluoroelastomer; EPDM and natural rubber swell in hydrocarbons within hours. On ethanol EPDM is acceptible. On CO2 the problem is different: elastomers absorb CO2 at 1,500 psi and above and blow apart from the inside when the pressure is dropped quickly, so O-rings and gaskets are chosen for explosive decompression resistance and the system is depressurized slowly. Brass stays out wherever the extract continues to food or supplement use because of its lead content.

Yes, through how fully it condenses, how far it sub-cools and how completely it drains. Terpenes boil well above 300 F and mostly stay in the collection vessel, but a condenser that floods or holds pockets of liquid lets light terpenes and water accumulate in the returned solvent run after run, and the next strain inherits the last one's aroma. A condenser with the chilled fluid at 0 to 20 F, a vent at the top for non-condensables and a drain at the true bottom returns clean liquid to the tank.

Mostly by the CO2 itself, which sweeps the separators and condenser on every run. The separator coolers and the surfaces downstream of them are where extract collects, and where a site changes between products with distinct profiles those are rinsed with ethanol and dried before the next run. That is why the CO2 exchangers on this page are 316L and drainable even though the duties are small and the design is about pressure: a coil or bundle that holds a pocket of extract cannot be shown clean. Ask for drain points at the true low point of every CO2 exchanger on the drawing.