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R. M. Jadhav and J. S. Sangwai
4.2 Effects of Dispersion on the Performance
of Nanoparticles
The means by which nanoparticles are introduced into heavy oil systems are also
important in determining the reduction of viscosity and upgrading of heavy oil. The
dispersion of particles in either the oil phase or water phase is crucial when it comes
to the interaction of these particles with the oil matrix. As the particles get dispersed,
the stability of the system increases which prevents the degradation of the catalytic
activity of the particles. The dispersion of the particles can be achieved in both oil
and water depending on the hydrophilic/hydrophobic or lipophilic/lipophobic nature
of the particles.
Metals and their compounds such as nickel and even the likes of molybdenum can
be dispersed using surfactants in water to be utilized for steam cracking processes
(Mironenko et al. 2017). Salts and other composites of transition metals also possess
the ability to catalyze upgrading operations. An example would be Keggin-structured
(heteropoly acid structure) catalysts which can aid viscosity reduction in aquathermolysis reactions (Chen et al. 2009). The main advantages of these acids are that
they are re-usable acid catalysts and can increase the catalyst life. Water-solubility
of nanoparticles allows a simple dispersion. These particles can be directly utilized
in aqueous applications by forming emulsions and stable mixtures for thermal methods. Water dispersed particles, though effective, can cause a hindrance when their
effects are mediated in the presence of oils. In this case, oil-soluble catalysts can
allow much better dispersion in the oil phase and be more effective that the watersoluble counterparts. Proper dispersion in the oil phase can improve the viscosity
altering effects during in situ processes. Oil-soluble nickel and cobalt are ideal at
producing catalyzing effects at low concentrations when used with hydrogen donors
for aquathermolysis process.
Certain types of catalyst nanoparticles which can be dispersed in both oil and
water called dispersed catalyst nanoparticles have shown remarkable performance
in recovery operations. These catalysts can be dispersed with the help of surfactants
or organic dispersants and have been found to be more effective than the usual oilsoluble and water-soluble catalysts. These catalysts can be in the form of organometals or suspensions of nanoparticles. Dispersed catalysts of nickel nanoparticles have
been used for the upgrading of heavy oil (Alkhaldi and Husein 2014; Li et al. 2007).
Effective aquathermolysis can be achieved in the presence of dispersed catalysts
because they can be dispersed in both oil and water. Since the dispersion in oil and
water is high, the contacting between these two can result in a better aquathermolysis
process allowing better cracking. Silica nanoparticles are extremely versatile as far
as dispersions are concerned. They can be dispersed quite efficiently in both oil and
water (Gavrielatos et al. 2017). They have excellent prospective in development for
heavy oil upgrading. They are a cheaper alternative to the metal and metal oxides
and are utilized widely.
The dispersions can also be made up of combinations of metals. Multimetallic
particles are something which is not common and these can be dispersed in heavy
R. M. Jadhav and J. S. Sangwai
4.2 Effects of Dispersion on the Performance
of Nanoparticles
The means by which nanoparticles are introduced into heavy oil systems are also
important in determining the reduction of viscosity and upgrading of heavy oil. The
dispersion of particles in either the oil phase or water phase is crucial when it comes
to the interaction of these particles with the oil matrix. As the particles get dispersed,
the stability of the system increases which prevents the degradation of the catalytic
activity of the particles. The dispersion of the particles can be achieved in both oil
and water depending on the hydrophilic/hydrophobic or lipophilic/lipophobic nature
of the particles.
Metals and their compounds such as nickel and even the likes of molybdenum can
be dispersed using surfactants in water to be utilized for steam cracking processes
(Mironenko et al. 2017). Salts and other composites of transition metals also possess
the ability to catalyze upgrading operations. An example would be Keggin-structured
(heteropoly acid structure) catalysts which can aid viscosity reduction in aquathermolysis reactions (Chen et al. 2009). The main advantages of these acids are that
they are re-usable acid catalysts and can increase the catalyst life. Water-solubility
of nanoparticles allows a simple dispersion. These particles can be directly utilized
in aqueous applications by forming emulsions and stable mixtures for thermal methods. Water dispersed particles, though effective, can cause a hindrance when their
effects are mediated in the presence of oils. In this case, oil-soluble catalysts can
allow much better dispersion in the oil phase and be more effective that the watersoluble counterparts. Proper dispersion in the oil phase can improve the viscosity
altering effects during in situ processes. Oil-soluble nickel and cobalt are ideal at
producing catalyzing effects at low concentrations when used with hydrogen donors
for aquathermolysis process.
Certain types of catalyst nanoparticles which can be dispersed in both oil and
water called dispersed catalyst nanoparticles have shown remarkable performance
in recovery operations. These catalysts can be dispersed with the help of surfactants
or organic dispersants and have been found to be more effective than the usual oilsoluble and water-soluble catalysts. These catalysts can be in the form of organometals or suspensions of nanoparticles. Dispersed catalysts of nickel nanoparticles have
been used for the upgrading of heavy oil (Alkhaldi and Husein 2014; Li et al. 2007).
Effective aquathermolysis can be achieved in the presence of dispersed catalysts
because they can be dispersed in both oil and water. Since the dispersion in oil and
water is high, the contacting between these two can result in a better aquathermolysis
process allowing better cracking. Silica nanoparticles are extremely versatile as far
as dispersions are concerned. They can be dispersed quite efficiently in both oil and
water (Gavrielatos et al. 2017). They have excellent prospective in development for
heavy oil upgrading. They are a cheaper alternative to the metal and metal oxides
and are utilized widely.
The dispersions can also be made up of combinations of metals. Multimetallic
particles are something which is not common and these can be dispersed in heavy