Page 84 - Energy from Toxic Organic Waste for Heat and Power Generation

70 Energy from Toxic Organic Waste for Heat and Power Generation

these wastewaters have a high organic load that does not permit its im-
mediate transfer into the sewage framework [3]. Solid by-products are the
deposits that incorporate squeezed seed cakes, agricultural wastes, and spent
earth. The biological solid deposits are commonly utilized in animal feed-
ing; however, these deposits and by-products can increase the revenue of the
biodiesel production if they can be utilized as a substrate for the production
of energy or chemical compounds.

6.2 BIODIESEL PRODUCTION
6.2.1 Raw Materials for Biodiesel Production
Biodiesel is a renewable and biodegradable fuel that can be derived from
a renewable and organic raw material such as fresh or waste oilseed plants,
vegetable oils, and animal fats. Burning biodiesel has considerably lower
emissions compared to that of fossil fuels and it can be used in its pure form
or blended with petroleum diesel [4]. There are many potential raw materi-
als used for biodiesel production as listed below.
1. Plant oils (edible)
2. Plant oils (nonedible)
3. Used edible oils
4. Microalgae
5. Animal fats

6.2.1.1 Plant Oils (Edible)
Biodiesel has been mainly produced from edible plant oils, which are easily
available on a large scale from the farming industry. Presently, most of the
biodiesel is derived from sunflower, rapeseed, soybean, and palm oils. Plant
oils are also known as chemically triglyceride molecules in which fatty acid
groups are esters-bonded to a glycerol molecule [5]. Plant oils from renew-
able oilseeds can be used when it is blended with petroleum diesel.
Merits of edible plant oils
1. Ease of availability
2. Higher heat content
3. Nontoxic (lower sulfur content)
4. Lower aromatic content
5. Harmless (biodegradability)
Demerits of edible plant oils
1. Higher viscosity (10–20 times greater than diesel)
2. Lower volatility