Microwave device for heat treatment of meat by-products and waste

Abstract

BACKGROUND: In the conditions of farms, there is a problem of neutralizing unpleasant odors during heat treatment of secondary meat raw materials to preserve the consumer properties of protein feed at low operating costs.
 AIM: Development of the device for heat treatment with disinfection and neutralization of the unpleasant odor of crushed secondary meat raw materials with the integral effect of an ultra−high frequency electromagnetic field, a bactericidal flow of UV rays and ozone in a continuous mode with electromagnetic safety ensured.
 METHODS: The raw materials are the stomach chambers of ruminants. The basic idea, principle of operation and design of the device are based on the propagation of microwave oscillations in a resonator with a spiral decelerating system. The microwave device contains a non-ferromagnetic cylinder with a perforated lower base, a coaxially arranged non-ferromagnetic spiral cylinder and an electrically driven fluoroplastic auger with a solid screw surface. The average perimeter of the annular volume, between the cylinder and the spiral cylinder forming the coaxial resonator, and its height are multiples of half-wavelength. Corona brushes are mounted to the annular base of the cylinder, under which electric gas discharge lamps powered by 1 kHz frequency generators are radially located, and a ceramic annular spherical surface is located under the lamps. Magnetrons are mounted along the perimeter of the outer cylinder with a shift of 120 degrees. The crackling is removed using a pneumatic conveyor.
 RESULTS: The feature of the coaxial resonator is that the inner core is formed as a spiral decelerating system. Therefore, the intrinsic Q-factor of the resonator is high, about 115000, therefore, the expected thermal efficiency is 0.7–0.75. The factor of dielectric losses of raw materials with a decrease in humidity from 76% to 30% is reduced by five times. Thus, while keeping the electric stress at the level of 1.2–2 kV/cm, the electromagnetic field power dissipated in a unit of the volume of the crackling decreases by five times, from 34 500 to 6800 W/cm3.
 CONCLUSIONS: A new design solution with a spiral coaxial resonator, the use of a ceramic reflector, and a number of physical factors made it possible to develop the design of the operation chamber for the heat treatment of ruminant slaughter waste with the neutralization of unpleasant odors with a capacity of 30–35 kg/h and specific energy costs of 0.16–0.19 kWh/kg.