i need a lot of dry ice....

[ah fai]

hallo everybody, i want to ask for help about
-how to produce dry ice?
-what kind of the refrigeration system and temperature need?
-it is possible i use it to freeze the fresh fish?
thank a lot........

i using bitzer screw osn7471-k compressor on my contact freezer.
-if suction pressure is -10psi, with mean evaporator temp around -40deg?

[mad fridgie]

Firstly you need a source of liquid CO2.
You then expand the liquid, through a throttling device, depending upon which type of dry ice you want, block, pellet, powder, then determines how you capture the revert vapour,. When captured re-compressor with oil free comp, liquify at CO2 tank pressure.
Not a cheap system

[NoNickName]

If you're ok with snowy dry ice, then just spray the liquid co2 in open air (-94 @ 1 bar).
Just buy a cylinder of liquid co2 and spray it over your food. No refrigeration system required.
These days, nitrogen is used, because it's much cheaper and more abundant.
It costs around 2 euro/kg and you can get around 250kJ/Kg (60Kcal/Kg) @ -195°C.
Nitrogen also keeps color and taste of food in a much better way. The freeze process is instantenous and extremely deep.

[ah fai]

thanks a lot for reply...
i do need block dry ice,and can i get more from ur??? like oil free compressor, how re-compressor works....

[mad fridgie]

thanks a lot for reply...
i do need block dry ice,and can i get more from ur??? like oil free compressor, how re-compressor works....

Let me explain, "oil free' compressor is term used in gas compression (not reaaly oil free) verses a compressor which is non lubricated,
Oil free relates to the compression part only of the compressor (pistons, compression cylinde) Bottom end is lubricated.
As you are using the CO2 directly on your product, purity has to be high "no oil" This is achieved by internal manufacture. Nomally but not limited to recip compressors (pistons), Normally 2 stage,
CO2 is taked frrom just atmospheric pressure and boosted to just above CO2 tank pressure. (15-20 bar). The pressure CO2 can be liquified prior entering the tank (basically a cascade refrig system) or the vapor can enter the tank directly then a thermosyphon refrigeration system (evap/cond) is mounted above the tank. This is not the sort of process you undertake your self.
Contact you local gas supplier!