RU2555239C1 - Method of container drying of seeds and grain and device for its implementation - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: method of container drying of grain consists in the fact that the grain is loaded, exposed with the drying agent, inverted, cooled and unloaded. The novelty is the fact that it is inverted in the stationary layer with the overloading into another container upon reaching at the critical height of the layer hcr of average grain temperature, overloaded n times in thin layers. The device for container drying of grain comprises containers, a fan, a heater, a furnace, he means of moving containers. The novelty is that the device comprises a diffuser with a central angle of less than α = 180-2β, where β is the friction angle of grain on the surface of the diffuser.

EFFECT: invention is aimed at providing the unevenness of drying necessary according to the initial requirements.

2 cl, 2 dwg, 3 ex

Description

The invention relates to drying of seed grain and can be used in agriculture and in the procurement system, mainly for valuable varieties of seeds.

A known method of drying grain in a fixed bed, according to which the material is loaded into the drying chamber, ventilated with a drying agent, cooled and unloaded.

A device for its implementation, including a furnace, a drying chamber, a fan, means of loading and unloading (S. D. Ptitsyn. Grain dryer. M., Mashgiz, 1968, 81 S.).

These method and device are widely used in agriculture, but the device requires manual maintenance (repeated manual mixing of grain), and the method is energy-consuming.

There is a known method of drying grain, according to which it is loaded, gravitationally moved, exposed to a drying agent, inverted, cooled and unloaded (V.A. Sharshunov, L.V. Rukshan. Drying and storage of grain. Minsk, Misanta, 2010, S. 271- 275).

Grain inversion is carried out in the shaft of the core dryer, while the layers adjacent to the gratings are rearranged.

This method is closest to the claimed and adopted as a prototype.

The disadvantage of this method is the incomplete rearrangement of the layers: the boundary parts of the layer adjacent to the grids do not rearrange to the opposite grids, but closer to the middle of the layer, which reduces drying unevenness to a lesser extent than when the rearrangement is complete, when the boundary layers rearrange to the opposite gratings.

A device for container drying in container boxes containing a perforated bottom with unloading flaps, a fan, air heater, means of movement (G.A. Rovny, Current state and main directions of development of drying plants for low-flowing agricultural materials. G.A. Rovny, F .L. Freger, A.V. Avdeev, I.L. Fishman. M., TsNIITEI tractor-agricultural farm, 1974, p. 12-13).

This device in its technical essence is closest to the claimed one and is taken as a prototype.

However, it does not provide the drying uniformity required by the initial requirements (δ≤ ± 1.5%), since it reaches ± 3.6%.

The objective of the invention is to provide uneven drying within δ≤ ± 1.5%.

, перегружают n раз тонкими слоями, при этом $$n=\frac{W_{н}-W_{к}}{6}$$

, где h_кр - критическая высота слоя, удовлетворяющая условию δ≤±1,5%, м (δ - неравномерность сушки); W_н, W_к - начальная и конечная влажность зерна, %; θ_н, θ_к - начальная и конечная температура θ_к=(t₁-3°C)≤θ_пд (t₁ - температура агента сушки, °C; θ_пд - предельно допустимая температура нагрева зерна, °C).The objective is achieved in that in the method of container drying, in which the grain is loaded, acted upon by a drying agent, inverted, cooled and unloaded, according to the invention, it is inverted in a stationary layer with overloading in another container when the grain temperature is reached at the layer height h _cr $${\theta }_{\mathrm{from}R}=\frac{{\theta }_n+{\theta }_{\mathrm{to}}}{2}$$

overload n times in thin layers, while $$n=\frac{W_n-W_{\mathrm{to}}}{6}$$

, where h _kr is the critical layer height satisfying the condition δ≤ ± 1.5%, m (δ is the drying unevenness); W _n , W _to - the initial and final moisture content of the grain,%; θ _n , θ _k - initial and final temperature θ _k = (t ₁ -3 ° C) ≤θ _pd (t ₁ - temperature of the drying agent, ° C; θ _pd - maximum permissible temperature of grain heating, ° C).

The task is also achieved by the fact that the device for container drying, containing a container, fan, air heater, furnace, means of moving the container, according to the invention is equipped with a diffuser (obelisk) with a central angle of not more than α = 180-2β, where β is the grain friction angle on the surface diffuser.

The invention is illustrated in the drawing.

In FIG. 1 shows a diagram of a device for container drying; in FIG. 2 - the process of loading into another container.

A device for container drying of grain includes a heater 1, a fan 2, an air channel 3, a grill 4, a seal 5, a socket 6, a discharge opening 7, a valve 8, a container 9, a diffuser (obelisk) 10 mounted on the container, a chute 11, a loader 12 , grain temperature sensor 13.

The device operates as follows.

(h_кр - критическая высота, удовлетворяющая условию неравномерности сушки δ≤±1,5%), м; θ_н, θ_к - начальная и конечная температура зерна, °C, причем θ_к=(t₁-3°C)≤θ_пд (θ_пд - предельно допустимая температура зерна, °C), погрузчиком 12 зерно из контейнера пересыпают в другой, вращая его относительно оси, проходящей параллельно желобам 11.The container 9 is loaded with grain, installed in slot 6, purged with a drying agent prepared in fan 1 by heater 2. Upon reaching the grain temperature at the layer height h _cr , equal to $${\theta }_{\mathrm{from}R}=\frac{{\theta }_n+{\theta }_{\mathrm{to}}}{2}$$

(h _cr - critical height that satisfies the condition for uneven drying δ≤ ± 1.5%), m; θ _n , θ _k - initial and final grain temperature, ° C, and θ _k = (t ₁ -3 ° C) ≤θ _pd (θ _pd - maximum permissible grain temperature, ° C), loader 12 pour grain from the container into another, rotating it about an axis running parallel to the grooves 11.

After emptying, the container 9 is filled with wet grain, and the grain is dried and cooled in another container.

The method is as follows.

Determine the moisture content of the grain and the critical layer height h _cr , fill the container with material with a layer height H = 2h _cr . A temperature sensor 13 is installed at a height of h _cr . A drying agent is applied to the grain; when temperature θ _{cp is} reached, pour the grain into another container with a thin layer h _c ≈ 2 ... 4d _e (where d _e is the equivalent diameter of the grain, so that the order of these layers changed to the opposite, they are again exposed to a drying agent, the material is dried to a conditional humidity (which, for example, can be determined by the temperature of the spent drying agent (3-5 ° C above θ _k ), cooled and unloaded.

On the grate 4, a drying front with a height of h _{cr is} formed and moves along the drying agent (for example, in the lower part of which the moisture content of the grain is 12.5, in the middle - 14.0, and in the upper - 15.5%). Moreover, the height h _cr depends on the initial moisture content of the grain, for example, at a moisture content of 22 ... 20%, h _cr = 0.17 ... 0.19 m, and at 25 ... 30% it decreases to 0.15 ... 0.16 m ranges of temperatures and speeds of the drying agent characteristic of the seed drying regime (V.F. Kabanov. Study of technological methods and working bodies providing intensification of drying of seed grain in a dense layer, Dissert. for the degree of candidate of technical science, M., 1979, p. 107-110).

, принимая, что температура возрастает прямо пропорционально снижению влажности зерна.The temperature of the dried grain on the lattice is θ _k = (t ₁ -3 ° C) ≤θ _pd , and at a height $${\theta }_{\mathrm{to}R}-{\theta }_{\mathrm{from}R}=\frac{{\theta }_n+{\theta }_{\mathrm{to}}}{2}$$

, assuming that the temperature rises in direct proportion to the decrease in grain moisture.

The layer-by-layer pouring of grain from the container 9 is carried out by its smooth rotation, while the material moves along an inclined surface formed by the container and the diffuser (obelisk). For the formation of a layer, starting with greater humidity and ending with less, a layered displacement of the material is necessary. This is achieved by braking a thin layer descending along the diffuser.

ограничивается величиной допустимого влагосъема в 6%, а тонкими слоями материал перегружают для снижения неравномерности сушки.Value $$n=\frac{W_n-W_{\mathrm{to}}}{6}$$

It is limited by the permissible moisture removal rate of 6%, and the material is overloaded with thin layers to reduce the unevenness of drying.

Complete emptying of the hopper is possible when its axis during rotation coincides with the vertical, with the central angle being α≤180-2β, where β is the angle of friction when the grain moves along the surface of the diffuser.

Example 1. Calculation of the kinetics of container drying at δ≤ ± 1.5% without tracking

Given: wheat seeds, initial moisture content W _n = 20%; final W _to = 14%; h _cr = 0.19 m; δ = ± 1.5%.

Container: grill area 1 × 1 m, fan flow θ _in = 1000 m ³ / h.

Permissible moisture removal by initial requirements - 6%. Choose a layer height h = 2h _cr ≈0.4 (taking into account shrinkage). The maximum allowable temperature for heating seeds is θ _pd = 49 ° C, but taking into account the unevenness of the seeds in terms of humidity, we choose 5 ° C lower, and the recommended temperature of the drying agent is t ₁ = θ _pd + 3 ° C = 47 ° C (V.I. Aniskin , G.S. Perch. Technological basis for evaluating the operation of grain drying plants. M: GNU VIN, 2003, pp. 80-82).

Then, at the initial grain temperature θ _n = 20 ° C, θ _cf = 32 ° C.

Upon reaching the grain temperature θ _cf at a height h _cr = 0.19 m, the layer is inverted and drying is continued.

The amount of evaporated moisture for the whole process will be:

,

,

where G is the initial mass of the grain, G = F · H · γ = 1 · 0.4 · 750 = 300 kg;

F is the lattice area, m ² ;

γ is the bulk mass of grain, kg / m ³ .

Heat consumption will be:

Q _t = Q _in · sec · ΔT = 27 × 10 ³ kJ / hr

where c is the heat capacity of the drying agent, kJ / kg · ° C;

ΔT - temperature difference, ° C, ΔT = 47-20 = 27 ° C.

The drying time will be:

,

,

where q is the specific heat consumption for moisture evaporation, q = 5.54 MJ / kg.

Example 2. Calculation of the kinetics of container drying with draining

Given: W _n = 25%; W _to = 14%; h _cr = 0.14 m; θ _pd = 42 ° C; t ₁ = 45 ° C; θ _n = 20 ° C; θ _avg = 33 ° C; H = 2h _cr ≈0.27 m; ΔW ₁ = 5%; ΔW ₂ = 6%.

The drying mode is as follows: the initial removal of 5% moisture is ΔW ₁ = 5%, and after curing, ΔW ₂ = 6%, while the layer is inverted twice (i.e., overloaded), the curing time is 0.5 ... 1 h, for this time evens out the moisture field in the caryopsis.

The mass of the loaded material in the container will be:

G ₁ = F · H · γ = 1 · 0.27 · 750 = 202.5 kg.

The amount of evaporated moisture will be:

.

.

The amount of heat supplied will be:

,

,

where ΔT ₁ = 43-20 = 23 ° C.

The drying time before curing is:

.

.

The mass of grain after the first moisture removal will be:

.

.

The amount of evaporated moisture after bedding is:

.

.

The amount of heat supplied will be:

.

.

The drying time after curing is:

.

.

The total drying time without taking into account the curing time will be:

Στ = 5.8 hours

Example 3. Grain with a moisture content of 25% and the parameters of Example 2 in laboratory tests were alternately blown on both sides by a drying agent with a temperature t ₁ = 45 ° C and a speed of 0.5 m / s in a cassette with a layer height H = 2h _cr = 0, 28 m and a diameter of 0.1 m. At a height h _cr = 0.14 m from the gratings, a thermometer was installed.

Upon reaching the temperature, the grain at this height θ = 32 ... 33 ° C and the cassette were turned over and drying was continued to a conditional humidity. Then the grain was cooled and unloaded with a periodic selection of samples for humidity.

According to the results of the experiment, it was found that the maximum deviation at average humidity at a temperature θ = θ _pd = 42 ° C of dried grain up to 13.5% does not exceed δ = ± 1.1%.

In the control experiment in the same cassette, under the same drying conditions, but with one-sided purging, the final humidity was 13.9%, and δ = + 2.0%, δ = -1.9%.

The effectiveness of the proposed method of container drying is due to the inversion of the layer at which the drying agent is reversed, and the unevenness of drying is halved compared to single-sided purging.

Claims (2)

1. The method of container drying of grain, which consists in the fact that the grain is loaded, treated with a drying agent, inverted, cooled and unloaded, characterized in that it is inverted in a stationary layer with overloading in another container when the grain temperature is reached at the layer height h _cr $${\theta }_{\mathrm{from}R}=\frac{{\theta }_n+{\theta }_{\mathrm{to}}}{2}$$

overload n times in thin layers, while $$n=\frac{W_n-W_{\mathrm{to}}}{6}$$

, where h _kr is the critical layer height satisfying the condition δ≤ ± 1.5%, m (δ is the drying unevenness); W _n , W _to - the initial and final moisture content of the grain,%; θ _n , θ _k - initial and final temperature θ _k = (t ₁ -3 ° C) ≤θ _pd (t ₁ - temperature of the drying agent, ° C; θ _pd - maximum permissible temperature of grain heating, ° C). 2. A device for container drying of grain, containing a container, fan, air heater, furnace, means of moving the container, characterized in that it is equipped with a diffuser with a central angle of not more than α = 180-2β, where β is the grain friction angle on the surface of the diffuser.

Images