Comparatives study of hydrogenated biodiesel and conventional biodiesel : technology and economics

Abstract

Hydrogenated biodiesel is referred to as diesel-like hydrocarbons that do not contain oxygen in their molecular structures. Hydrogenated biodiesel can be produced by the hydrotreating of vegetable oils or fatty acids with a standard hydrotreating catalyst and at standard condition (NiMo/y-AI₂O₂, 300 °C to 450 °C, 500 psia to 2000 psia) Hydrogenated biodiesel is superior to regular biodiesel in heating value, cetane number, and oxygen content. In order to produce hydrogenated biodiesel on a commercial scale, the technology and economics of this process must be evaluated. In this study, the technology and economies of hydrogenated biodiesel are compared to that of biodiesel production, using ICAS and PRO/II® programs. For hydrogenated biodiesel process, an option of having steam methane reforming (SMR) unit was also evaluated. The results indicate that with palm oil as the feedstock and a capacity of 200 000 tons product/year, the capital and the manufacturing cost of hydrogenated biodiesel process are higher than that of the conventional biodiesel process. Reactors and distillation columns account for the major of the capital cost for biodiesel process while compressors and hydrotreater are the major capital cost of hydrogenated biodiesel process. Adding SMR to hydrogenated biodiesel process could reduce the manufacturing cost of hydrogenated biodiesel It was also found that in order to produce same amount of product, hydrogenated biodiesel requires higher amount of vegetable oil feedstock than biodiesel. Therefore, the production cost of biodiesel is lower than that of hydrogenated biodiesel. However, in terms of energy produced, the economics of hydrogenated biodiesel and biodiesel processes are comparable.