Cracking-still gas

The hydrogen sulfide available from natural gas, cracking-still gas and refinery gas, along with the sulfur in crude oil, amounts to more than enough to produce the entire sulfuric acid needs of the nation,... 

Cracking. Materials such as cracking-still gas, pressure distillate, cracked gas oil, and pressure-still tar are products of cracking. By cracking we refer to the decomposition of heavy or high-boiling oils by exposure to extreme temperature. At temperatures exceeding about 680 F materials such as gas oil, fuel oil, and tars are decomposed into (1) gas, (2)... 

---