If your pump is very weak (like a c/h pump) an eductor won't work as the pump won't have the power to drive it. If the pump is powerfull, like a tam 120 then the mixing is so efficient anyway that an eductor doesn't make any difference. it is the medium power pumps, tam 105 and similar, where an eductor is most efficient.
The more methanol you use, the less catalyst is reqd.
The more stages you do, then total chemical usage is lower.
When I did a lot of conversion expts 2 to 3 years ago, i did a process where I only used 3.5gms KOH/litre for full conversion, but used 7 stages, just to see. I posted this on infopop and vod, there were some that didn't believe me, each to his own.
Nowadays I intentionally do 3 stages after glyc washing. My 1st stage (depending on conversion after the glyc wash) has only 9 to 11% added methanol, but I have to be carefull not to starve the process too much.
As I use the 2/3 1/3 ASM/KOH catalyst it can be counter productive to use too little methanol as more catalyst is reqd.
I always end up with more de-methed bio than oil I started with and my glycerol volume is about 2/3 of the amount of methanol added.
During warmer weather, I start stage 1 at ambient then apply heat more as the stages proceed. I like S2 to show about 0.3 mls dropout so the last stage only reqs a very small amount of ASM only for completion at 60 degs. I now take the reaction up to this temp simply to reduce the monoglycerides when water washing.
I must say, using the ASM/KOH mix has totally transformed my process. Can I give you my account details Nigel, so you can pay the commisions direct.
