Waste rubber seeds as a renewable energy source: direct biodiesel production using a controlled crushing device.

A multistep and high-cost biodiesel production could be simplified using the direct transesterification (DT) method. A controllable device has been developed and applied to study the effects of the ratio of rubber seeds to methanol, catalyst concentration, reaction time and rotational speed on biodiesel conversion and fatty acid (FA) yield extraction. The controllable crushing device (CCD) assisted the DT of rubber seeds and operated at ambient temperature and pressure achieved a maximum biodiesel conversion of 97.

Direct biodiesel production from wet spent coffee grounds.

Utilization of waste spent coffee grounds (SCG) remains limited and requires pre-treatment before being discarded to avoid pollution to the environment. Lipids contained in SCG could be converted to biodiesel through an transesterification method. Current transesterification of wet SCG biomass, conducted at high reaction temperature to reduce the water effect and reduce reaction time, is energy intensive.