Abstract:
Nowadays, the main sources of energy are natural gas and crude oil from the Earth's oil drilling process. Using the above materials produces a large amount of carbon dioxide (CO2) and is the main factor contributing to global warming. Reducing CO2 emissions can be achieved by the use of biomass as an energy source instead of drilling for oil. Hydrothermal liquefaction (HTL) is an interesting process that can convert biomass into liquid or biocrude products. Adding a catalyst into the process helps improve the quality and yield of liquid products from the HTL. Char is considered to act as a catalyst in the process. The char is inexpensive and can be easily produced from biomass. Moreover, the activation of char by steam enhances the char porosity and surface area. In this research, the effects of steam-activated chars on biocrude yield and quality by hydrothermal liquefaction were studied. The experiments were carried out in a high-pressure batch reactor at temperatures of 300-350 °C with a reaction time of 60 min. Chars were activated by steam at 800-900 °C with a reaction time of 120 min. The quantity of liquid was increased when adding palm kernel shell char and bamboo char because char was found to have a catalytic effect on biomass cracking. The influence of liquefaction temperature was also examined in a range of 300 to 350°C. At a higher reaction temperature, biocrude yield was decreased while gaseous products were increased. In addition, when using activated char in the HTL process improve the quality of biocrude oil imterms of the High heating value (HHV).