Low Pressure Steam Boiler

[Born_Free]

The original design was a steam injection system (a knockoff of Bolverk’s design, Bolverk 2.0?).

I was curious about distilling with a really low surface temperature vs a high one like an electrical element, will it help with foaming of rye mashes or change the flavour? Would also be nice to not add water while stripping.

I know this may scare the shit out of some and….. it should…… so I’ll start with the anti-boom stuff.

Pressure Relief Valve = 8 PSIG
Pressure Switch High High = 7 PSIG
Pressure Switch High = 6 PSIG (will lower to 4 or 5 PSIG)
PID Pressure Control Range = 0-5 PSIG
Vacuum Relief Valve (-6.8 in H20)

Overpressure tested with CO2 before each use, it takes 5 minutes (only because I have a very accurate regulator on my beer system) and vacuum tested by filling with water then draining. PSH and PSHH have separate trip relays that kill power.

This is a closed system with no valves/restrictions in the steam path and a minimum diameter of ¾” pipe. Condensate return is above the water line. Steam coil is 15 ft of total pipe in a 13-gallon boiler.

With that out of the way…. steam pressure control is incredibly self limiting. I have not overshot the setpoint by more then 0.1psig. Spent a good deal of time modelling this before building, probably too worried about the PID tuning but wanted it perfect out of the box. There is a trade off between performance and safety when choosing a steam volume.

For stripping runs the steam pressure does not exceed 1 psig during warm up and while boiling it doesn’t get above 3 psig that’s 222F/105C max coil surface temp.