it really depends on what your using for slime…
for instance… you can buy a fire extinguisher that you fill with water, screw the cap on, hook up an air compressor too it, and then it will shoot water 20+ feet. you could buy two of those for the tanks on the side and have a dummy tank in the middle.
but how well would that work with a thicker substance?
Really you could cause just about anything to propel with compressed air, its just a matter of finding the proper equipment of doing it.
For instance if you wanted to use a thicker substance like your easy cheese… then the fire extinguishers more then likeley wouldnt work… the lines are designed for a substance with similar properties to water.
So really you could custom build a whole system to blow a substance but it would be much more practicle for it to shoot a pink colored water (aka pink lemonade)