RU2368851C1 - Method of drying procedure in microvave field - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention refers to bulk produce drying and can be used in agricultural industry to dry seeds, particularly corn heads and other crops in order to obtain seed grains. According to the invention produce are dried in microvave field at a temperature of 30-35°C in vacuum under residual pressure of 50-100 Mm hg, which is maintained at continuous dry air or inert gas blowing.

EFFECT: invention ensures drying time and energy cost reduction.

Description

The invention relates to the field of drying bulk agricultural products and can be used in the agricultural industry for drying seeds, in particular heads of corn and other late-ripening crops, to obtain seed.

One of the most acute problems in obtaining conditioned seed of various late-ripening crops is the preservation of its sowing qualities under conditions of prolonged storage (in particular in winter or for a longer time). Long-term storage of grain is possible if the grain moisture does not exceed 10-15%.

In most of Europe, late-ripe crops (corn, sunflower, etc.) are harvested at a grain moisture content of 20-50%. Such grain is not subject to long-term storage due to infection with fungal diseases, followed by mold. A grain of this moisture loses its sowing qualities during storage, namely, germination energy and germination.

As a rule, in a production environment, the problem of bringing both food grains and seeds (seeds) is solved by drying on special dryers of various types, but these processes are time-consuming and energy-intensive. Known methods of drying products of plant origin using microwave radiation (microwave) in combination with a vacuum separation of water. The use of microwave technology in agriculture can significantly reduce energy costs, which make up more than 30% of the cost of production. The use of microwave energy makes it possible to disinfect agricultural products from phytopathogens of various types causing grain spoilage [Kalinin L.G., Tuchny V.P., Levchenko S.A., Babayants O. V. Microfibre field infiltration into phytopathogens - the main stomata occurring in grains i sleepyhead. Mikrokhvilovi technology in the national statehood. Tuesday. The problems. Perspectives: Journal of articles, vip.2-3, Kyiv-Odessa, TEC, 2000 pp. 73-77]. Using the energy of the microwave field reduces the microtrauma of seeds of grain crops, which makes it possible to maintain high grain quality during long-term storage, in particular, germination and germination energy of seeds. In addition, the positive effect of the influence of the microwave field on the seeds of cereal, oil and other crops lasts five or even more months, which allows, using the microwave technology of drying the seeds before putting it into storage (that is, long before sowing), to exclude the operation of presowing stimulation of the initial growth .

A known method of vacuum drying products of plant and animal origin, according to which the products are dried by heating and mixing in a sealed vacuum chamber, followed by separation of water and pumping gases [RF patent No. 2151984, class. F26B 7/00, 5/04, 3/347]. At the same time, a residual pressure of 3-5 Pa is created in the chamber, water is evaporated when the product is heated with microwave energy to 70-90 ° C, and drying is carried out until the product reaches a moisture content of 9-13%.

A known method of drying materials in containers [RF patent No. 2248886, class. F26B 7/00, 3/347], in which the material is packaged in a breathable container and is dried in two stages. At the first stage, they are dried with microwave energy with simultaneous evacuation to a critical temperature for the material that is being dried (the critical temperature is different for each material), and then they are only kept under vacuum until the specified humidity is reached.

A known method and device for processing agricultural products [RF patent No. 2242906, class. A23L 3/40, 3/54, F26B 7/00, 11/18]. The method according to the invention includes loading products into the chamber in trays in a positionally-regulated position, creating a vacuum and providing complex heating of the material due to heat air flow, ultrasonic elastic vibrations, infrared and microwave radiation. During steam condensation, fractional separation and disposal of volatile components and extract are carried out in individual receivers. Food trays are freely suspended on the drum with the possibility of rotational movement of the base axis and periodic approach and removal of the raw material relative to the radiation source.

The disadvantages of the above methods is the high temperature (more than 45 ° C) and the duration of drying with significant energy consumption. The use of these methods for drying seeds in order to obtain seed does not ensure the sowing quality of seeds (germination energy and laboratory germination), because at a temperature of 40 ° C and higher, protein coagulation begins and seed embryos lose their viability.

A known method and device for drying bulk dielectric materials [patent of Ukraine No. 64308, class. F26 3/347, 7/00, 9/06]. The method according to the invention includes evacuating the volume with the material, microwave heating it using dry air and drying to achieve the desired moisture content of the material. The technological mode of drying, in accordance with this invention, namely: pressure 20 mm Hg and less, as well as a drying temperature of up to 80 ° C, makes it impossible to use it for drying bulk agricultural products, namely seeds to obtain seed, since the necessary sowing qualities are also not ensured, in particular, their germination is lost when drying seeds.

As a prototype, we have chosen the method of drying bulk dielectric materials according to the patent of Ukraine No. 64308.

The basis of this invention is the task of improving the drying method, which would provide the possibility of drying bulk agricultural products, in particular seeds, reducing the drying time, reducing energy consumption while maintaining seed quality, namely, germination energy and laboratory germination.

The solution to the problem, which is the basis of this invention, is provided by the fact that in the method of drying bulk agricultural products, which includes loading the products into the drying chamber, evacuating the chamber volume, microwave heating and drying, according to the invention, the drying is carried out in vacuum at a residual pressure of 50- 100 mm Hg, which is maintained at this level by constant purging with dried air or an inert gas, at a temperature that does not exceed 30-35 ° C.

The temperature regime of drying, namely 30-35 ° C, is optimal, since at a temperature above 35 ° C the probability of loss of seed germination increases, and at a temperature below 30 ° C the drying speed is significantly reduced, which leads to an increase in the duration of the process. The optimal residual pressure in the system is determined experimentally and is maintained at a level of 50-100 mm Hg. At a system pressure of less than 50 mmHg there is a sharp decrease in sowing qualities of seeds due to depletion of seeds with oxygen. At pressures greater than 100 mmHg drying time increases, which leads to an unjustified increase in energy consumption.

Example 1. 10 kg of heads of corn with a grain moisture content of 42-45% are loaded into the drying chamber, vacuum at a residual pressure in the chamber of 60 mm Hg, pressure is maintained at this level, controlled by blowing with an air stream, microwave heating is turned on, drying is carried out at a temperature of 30 ° C for 12 hours and dried heads of corn are unloaded. The moisture content of dried heads of corn is 11-13%.

According to studies, laboratory germination of corn was 98%, and germination energy - 96%.

Example 2. 10 kg of sunflower seeds with a moisture content of 40% are loaded into the drying chamber, vacuum to a residual pressure in the chamber of 50 mm Hg, pressure is maintained at this level by regulating by blowing with an air stream, they include UHF heating, drying is carried out at a temperature of 30 ° C for 14 hours and unload the dried sunflower seeds. The residual moisture content of the seeds is 13-14%.

According to studies, the laboratory similarity of sunflower was 99%, and the germination energy was 95%.

The proposed method of drying agricultural products provides a reduction in the duration of the drying process by 2 times and a reduction in energy consumption by 5 times in comparison with existing modern drying technologies.

Claims (1)

A method of drying agricultural products in a microwave field, which includes loading products into a drying chamber, evacuating the chamber volume, microwave heating and drying, characterized in that drying is carried out in vacuum at a residual pressure of 50-100 mm Hg, supported by continuous purging with dried air or inert gas at a temperature of 30-35 ° C.