Nitrogen is removed from the rules, only CO2, or compressed air on low pressure.

Also, a 120*180 ram is at least 12 kg, if a commercial available ram is used. And delivers on its own 1.5 times more power than a 100mm bore ram.
With 2 of these gasguzzlers, youre emptying a 2 kg CO2 bottle in 2 actions. And then the question of valves. Each one will need a 1 bsp or equivalent inlet valve (meaning 4 burkerts =2.5 kg at least).

Then the LEM130s. Youll need a boatload of batteries to provide the power, and then deal with it.

A nice vaporbot, unless you got acces to aboutish £50 000.