ABSTRACT
In the past, humans derived their daily energy needs mainly from bioenergy, such as rewood, through simple biomass burning. Thus far, a large part of energy consumption for heating and cooking in undeveloped regions is still similar to the ways of the past. The biomass productivity per land area is low, so the forests in those regions have become bare and barren. On the other hand, in developed countries, most of the energy for transportation, plant operation, lighting, home heating and cooking, etc., originates from nonrenewable sources, such as fossil oil, coal, and natural gas. Therefore, a more effective use of renewable energy is needed for sustainability and environment issues. “Sustainable energy is the sustainable provision of energy that meets the needs of the present without compromising the ability of future generations to meet their needs” (Freya and Linke 2002). Sustainable energy should satisfy the following: First, all the raw materials needed to produce the energy will not be depleted because they are innite or involve
CONTENTS
33.1 Introduction ........................................................................................................................ 717 33.2 Biofuel Production Processes Using Microalgae ........................................................... 719 33.3 Basic Knowledge of Hydrothermal Liquefaction .......................................................... 720
33.3.1 Characteristics of Subcritical and Supercritical Water ..................................... 720 33.3.2 HTL Equipment ..................................................................................................... 721
33.4 HTL Reaction Characteristics of the Microalgal Component ..................................... 721 33.4.1 HTL of Lipids ......................................................................................................... 721 33.4.2 HTL of Proteins ......................................................................................................722 33.4.3 HTL of Carbohydrates...........................................................................................723
