A court has sentenced the head of a Taiwanese company to 20 years in jail for his role at the centre of a 'gutter oil' scandal that gripped the island's for industry and brought down a minister Yeh Wen-hsiang , chairman of Chang Guann Co , was also fined Tw$50 million ( 56 million baht) for his part in selling on 243 tonnes of tainted oil collected from cookers , fryers and grease traps , as well as recycled grease from leather processing plants.