Lime Silo Bin Aeration

Posted in: , on 27. Apr. 2007 - 19:16

I am trying to setup a bin aeration system for a lime silo at a waster water treatment plant. The is my first time trying to design one of these systems. I decided to desing around the aeration nozzles produce by Monitor. There would be 20 of the nozzles on each of two silos. each of these nozzle is meant to flow 4 scfm @ 5 psig. The combined flow for one silo is then 80 scfm @ 5 psig. I have heard two conflicting opinions on whether to operate these nozzles continuously or only when needed. If operated continouosly, then a roots blower would be the best way to go. The problem is that there are no air drying systems that I can find that are meant to be used at low pressures (5 psig).

If operated only when needed then using high pressure compressed dried air stored in a receiver would work fine if followed by a pressure reducing valve. Unfortunateley I can't find a pressure reducing valve that a) goes down to 5 psig & b) state that it is meant for air. Any help would be much appreciated. Has anybody else here designed such a system? What is a typical setup (it's funny, the people at Monitor have no idea what a typical setup is)? keep in mind that the lime is sensitive to moisture, so the air going in has to be dried.

Process Mechanical Engineer

Re: Lime Silo Bin Aeration

Posted on 27. Apr. 2007 - 09:07

By nozzle I assume u mean aeration pads. If the cone is at least 60 degrees, then 20 on each cone is way over the top, 6 normally work just fine for a decent size outlet if placed at right height from the outlet. Aeration is only required during start of silo discharge once lime starts flowing it usually flows even with the aeration switched off. Lime is very sensitive to moisture so make sure the air is very dry which might not be the case with roots blower especially for high humid climate. Instrument quality dry plant air with pressure regulator is the option I normally go for.

Mantoo