In ohmic heating electrical energy is dissipated in heat with a very high efficiency (electrodes in contact with the reaction medium), resulting in fast and uniform heating and in the increase of charged species movement. As in the case of the heating with microwave radiation, electrical energy is transformed into thermal energy. However, on contrary of heating with microwave radiation (penetration depth of microwave radiation in absorbing media is limited) the penetration depth is virtually unlimited and the extent of heating is regulated only by the spatial uniformity of electrical conductivity throughout the reaction medium and the time spent in the ohmic reactor. Thus, the direct scaling of the ohmic heating for the pilot or industrial scale shouldn’t have the limitations presented by microwave radiation heating. It is also possible to reduce reaction times and increase the energy efficiency of chemical reactions
Description of the technology
A group of researchers from 3 public universities has developed an ohmic heating reactor for chemical synthesis, particularly in aqueous media. This reactor and the heating method found application in organic and inorganic synthesis, preparation of organometallic materials, synthesis of nanoparticles and polymers, being applicable in the chemical and pharmaceutical industry. The simplicity and low cost of the reactor, its low heat capacity and thermal inertia, the fast and uniform heating, high efficiency, easy maintenance and handling, as well as the possibility of visual monitoring of the reaction evolution and the possibility of adding reagents during the course of the reaction, make the use of this reactor a versatile and advantageous option for synthetic procedures.
The present invention relates to an ohmic heating reactor and the application of this heating method in chemical synthesis, particularly in aqueous media. This method emerges as an alternative to the classical heating and microwave radiation. In the ohmic heating the reaction mixture (material to be heated), which functions as an electrical heater, is heated by passing electricity trough it. The power generated depends on the applied AC voltage, the impedance and the current generated. Using a sinusoidal high frequency voltage, the time interval of electric polarization minimising the occurrence of oxidation reduction side reactions was decreased. The use of high frequency leads to the minimization of the system polarizability leading to a higher electrical efficiency decreasing the capacitive component. The electrical energy is dissipated directly into the reactor as heat with high efficiency, resulting in fast and uniform heating (uniform temperature) and in an increase in the charged species movement. This invention is applicable, for example, in the chemical and pharmaceutical industry, particularly in synthetic procedures.
Main advantages of its use
- Penetration depth virtually unlimited -the extent of heating is regulated only by the spatial uniformity of electrical conductivity throughout the reaction medium and the time spent in the ohmic reactor
- The present invention has clear advantages relative to the existing technologies, such as: fast and uniform heating
- It can also be applied to the synthesis of materials (preparation of organometallic materials and synthesis of nanoparticles).
- Synthetic processes in the pharmaceutical industry.
- Synthetic processes of chemical industry (chemicals, agrochemicals and polymers)