Low Power Comsumption By Hammer Mill. 468 MJMg for both hammer and knife mills. Hammer mill required more energy 414 MJMg than a knife mill 180 MJMg for 3.2 mm particle size. They observed that agricultural straw and corn stover required 6 to 36 of the effective specific energy required for wood. Vigneault et al. 21 observed a 13.6 saving in ...