Oil from wood Oil from wood the Wheeler process, has two stages: Add sulfuric acid to wood. This is a very old pretreatment process that dissolves/breaks down lignin making cellulose available. Heat the pulp with calcium hydroxide at 450 degrees Celsius, to remove oxygen. This produces a hydrocarbon mixture similar to crude oil. Distillation produces a petrol fraction with an octane of 80. The acid and calcium hydroxide are recovered. More..