Purification of biodiesel using a natural based adsorbent in a packed-bed column Conference Paper uri icon

abstract

  • In Europe, the Renewable Energy Directiva stimulates the development of renewable energy sources to reduce greenhouse gas emissions by at least 55% by the year 2030 and to become aclimate-neutral continent by 2050 [1]. Biodiesel presents advantages over diesel fuel in terms of sulfur content, biodegradability, flash point, no aromatic content, higher cetane number and miscibility in petroleum diesel in any ratio [2]. The most used feedstock is high quality vegetable oil, but the use of waste cooking oil adds to the global reduction of residue, lower costs, and competes less for vegetable oils against the food industry [3]. This biofuel is obtained through transesterification, and glycerol is formed as a coproduct. lts presence can cause damage to motors so it must be removed until its final concentration is lower than 0.02wt%. The most used method is wet washing, but the downside is the great amount of water used and long periods of time are needed to separate biodiesel from its contaminants through decantation [4]. A promising altemative is dry washing method through adsorption using biomass activated carbon. For a more practica! application, packed columns are frequently used in large scale adsorption processes. lt is one of the most efficient configurations for treating great volumes of effluent and adsorption-desorption cycles [5]. For this study, crude biodiesel was produced through transesterification from a waste cooking oil sample, using ethanol and a basic catalyst (NaOH). Afterwards the biodiesel produced was characterized in terms of glycerol content. In parallel, activated carbon materials were obtained from olive pits by physical activation at 800°C. The adsorbent materials performance for glycerol removal from crude biodiesel is assessed using a continuous system based on a packed-bed column according to the following parameters: fluid rate, removal capacity, pressure drop and adsorbent recovery.
  • The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financia! support through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021).

publication date

  • January 1, 2023