Critical review on the current scenario and significance of crude glycerol resulting from biodiesel industry towards more sustainable renewable energy industry

Biodiesel production through transesterification of vegetable oils and animal fats is rapidly increasing due to strong governmental policies and incentives. However, corresponding increase in the production of crude glycerol causes mixed effects. Sustainable biodiesel production requires optimization of its production process and drastic increase in the utilization of glycerol. High biodiesel yields and low environmental impacts, with respect to needless waste streams are mandatory. As such, upgrading of crude glycerol to highly pure glycerol and subsequent utilization of the product in producing value-added products are emerging research areas. International crude glycerol market is still at an early and very unstable stage. Globally, future conditions for an international market will largely be decided by supply and demand of glycerol for its utilization in conventional and newly developed industries. This paper highlights the current scenario on glycerol production from biodiesel industry, its global market and its new emerging outlets as commodity chemicals.