1-805-484-2992
Quotes - Engineering - SalesJuice plants
The caustic heater behind a juice line
Juice equipment fouls in two ways at once. Pulp, fiber and seed fragments lodge in extractor screens, finisher baskets and pump housings, while pectin and fruit sugar bake onto every hot surface in the pasteurizer and the evaporator. Fruit acid adds a third layer: tartrate and citrate salts with calcium from the water that form a thin, hard scale where the product was heated. The pre-rinse carries the loose solids back to the CIP tank, so the heater on that tank sees pulp in the caustic, and the caustic has to be hot enough to soften a pectin gel that insulates whatever it coats.
The wash that works is 1–2% sodium hydroxide at 155–165°F for 30–40 minutes, acid at about 1% and 130°F on a schedule for the mineral, and a final rinse at 120–140°F. Juice plants mostly run tank recirculation, because the extractor hall, the pasteurizer and the blend tanks are washed from one CIP set in turn.
A typical set holds 1,500 gallons of caustic. Taking that tank from 80°F at the end of the night to 160°F in 30 minutes is about 2 MBtu/h, and the heater in the tank loop is sized for that recovery rather than for any one circuit's flow.
A 1,500-gallon caustic tank to 160°F in 30 minutes takes 2 MBtu/h
That duty comes from the sanitation window, not the circuit. Allow 60 minutes and the heater halves; demand 15 minutes and it doubles. Tell us how long the schedule gives the tank and we size the bundle to that clock.
The circuit: pulp in the return, gel on the surfaces
Juice CIP circuits run pulp-laden. Even after a pre-rinse, fiber and fines ride back to the tank and settle, and the tank loop pump lifts them straight into the heater. Caustic saponifies little here because there is almost no fat; its job is to swell and dissolve pectin and to loosen the burnt sugar film in the pasteurizer holding tubes. Both go faster above 155°F, and plants that hold 140°F to save steam find the evaporator still brown at the end of the wash.
The acid step is not optional in a juice plant. Calcium citrate and tartrate scale resist caustic entirely and build up at the hot end of the pasteurizer. Phosphoric at 1% and 130°F every few days keeps it in check, and because citrus plants often run their acid warm and often, the acid step has to be told to us when the heater is quoted.
The heater: a removable U-tube with a strainer ahead of it
A U-tube shell-and-tube with steam in the tubes and caustic on the shell side is the construction for this tank. Pulp and pectin foul the shell side; the steam side stays clean, and the free expansion of the U-bundle takes the thermal cycling of a tank that goes from 80 to 160°F every night. The shell, bundle and heads are 316L. We size with a fouling allowance of 0.001–0.002 on the solution side, and we recommend a basket strainer between the tank loop pump and the heater so fiber does not mat on the bundle.
Steam at 50 psig gives 298°F in the tubes and a comfortable approach to 160°F caustic. If the plant also wants a return-to-makeup recovery exchanger, that is a 316L plate pack with EPDM gaskets on the return line, and it cuts the steam heater's duty without changing its construction.
What to send for a juice plant caustic heater
A juice plant quote is about the tank and the clock. Give us these and we return a bundle size, shell diameter and the steam flow the boiler house should expect at start-up.
- Caustic tank volume and the time allowed to reach temperature
- Lowest tank temperature at the start of the heat-up
- Target caustic temperature and concentration
- Tank loop pump flow in gpm
- Acid type, strength and how often the acid step runs
- Steam pressure at the CIP set
Call and talk it through with an engineer: 1-805-484-2992
Juice processing questions
Not if it is kept off the bundle. Fiber mats on the first tube rows and raises the pressure drop before it hurts heat transfer. A basket strainer sized for the tank loop flow ahead of the heater collects it, and the removable U-bundle lets you clear anything that gets through. Plants that skip the strainer end up pulling the bundle every few weeks instead of every season.
Often it is the temperature at the far end of the circuit. A long run to the pasteurizer loses 10–15°F, so caustic that leaves the tank at 150°F reaches the holding tubes well under what burnt sugar needs. Raising the tank set point to 165°F, and sizing the heater to hold it with the circuit running, usualy clears the film.
If sanitation can wait, yes. The same 1,500-gallon tank that needs 2 MBtu/h for a 30-minute heat-up needs half that over 60 minutes. The trade is production time. In citrus season, when the extractor hall washes several times a day, the minutes matter more than the surface area. We quote both so the plant can choose.
No. Residual citric or malic acid is mild and well diluted by the time it reaches the tank, and 316L is unaffected by it. The elastomer question is about the CIP acid step, not the fruit. Phosphoric acid at 1% is gentle on EPDM; if the plant runs hot nitric instead, say so and we fit FKM on the solution-side head gasket.
Related
Applications
Drink Production CIP
Carbonated lines hand the CIP heater two problems: sugar film that needs 150°F and CO2 that eats caustic strength. An inline heater for a 4-inch loop at 120 gpm.
+ Learn More
Applications
Coffee Processing CIP
Coffee oil polymerizes into a varnish that only hot, strong caustic will move. Why a coffee plant heater is often a brushable straight-tube unit for a 175°F tank.
+ Learn More
Applications
Juice & Soft Drink Lines
Juice and soft drink lines clean often, run acid most days and dump a lot of warm return. The caustic heater, the gasket for the acid, and where recovery pays.
+ Learn More
