Category: ENERGY

Birth of Nuclear Energy

The alpha decay of U-238 occurs naturally, but in the 1930s Otto Hahn, Lise Meitner, and Fritz Strassman began to study the neutron-induced radioactive decay of ura­nium. Bombardment of a target nucleus with neutrons can result in elastic collisions (the neutron just bounces off with a loss of energy), inelastic scattering (leaving the target nucleus […]

NUCLEAR CHEMISTRY BASICS

9.2.1 General Chemistry Review The energy conversions we have examined thus far have relied primarily upon cap­turing the energy of chemical reactions that center on electron transfer or excitation. We have been able to ignore, if you will, the rest of the atom—until now. Nuclear power comes about from release of the binding energy of […]

Nuclear Energy

9.1 INTRODUCTION As noted in the introduction to this book, there are several relevant topics that would not be covered even though there is legitimate claim to their inclusion. Given that limitation, why include nuclear power? After all, it is a topic that is highly contro­versial with respect to sustainability and certainly one with a […]

8.6.3.5 Conclusions

The production of FAE biodiesel has well-established and reliable technology behind it and biofuel plays a minor, but significant, role in many areas of the globe. Industrial-scale applications have much room for improvement, however, and in the end analysis, FAE biodiesel is a first-generation biofuel that, in many instances, competes with food production. New methods […]

Process Conditions

Lipase catalysis takes place, as expected, at lower temperatures and in general must be carried out at temperatures below 60°C, at which point the lipase is deactivated. However, catalysis of FAEE biodiesel produced from soybean oil with Novozym 435 gave the optimum yield of 92% when carried out at 65°C (Brusamarelo et al. 2010). Just […]

Immobilization

Because of the high cost associated with these enzymes their practical application requires immobilization in or on some solid material that allows their easy recov­ery. Immobilization of the lipase on a solid inert material not only results in cost savings due to recycling, it also stabilizes the lipase. As a result, fixed bed reactors (such […]

Lipases

Triacylglycerides are lipids and the enzymes known to catalyze lipid esterification, hydrolysis, and transesterification (and, hence, biodiesel production) are, logically enough, lipases. These enzymes are widely distributed in nature, being produced by microorganisms as well as plants and animals. Microorganismal lipases from the genera Candida, Rhizopus, and Pseudomonas are the primary sources for industrial applications. […]

Enzymatic Catalysis

Given that the production of FAE biodiesel is based on a biological feedstock it stands to reason that biological catalysis is an option. Indeed, enzymatic catalysis of FAE biodiesel production is a well-studied phenomenon for the usual good reasons: enzymatic catalysis leads to a much milder, greener chemical transformation given a lower temperature of reaction […]