RU2445560C1 - Method for drying high-moisture products and device for its implementation - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: method for drying high-moisture products envisages gas suspension movement along the recirculation drier divided pneumatic tract, return of the coarse fraction of the product into the tube drier after pre-drying in the mechanical crusher and regulation of return of the fine fraction using an additional fan downstream the after filter. According to the invention, in the tube drier one performs intermediate aerodynamically controlled division of the flows of the drying agent and the pneumatic tract suspended particles with recirculate separation; the quantity, dispersion and moisture content of the recirculating product are regulated by variation of the difference of the values of the drying agent divided flows aerodynamic pressure depending on the product moisture content at the drier outlet, the extracted recirculate is additionally classified with fresh drying agent or supplied into the zone of the product most intensive thermal and mechanical treatment. The device for drying high-moisture products contains a feeder, a ripper rotor, a tube drier, a separator or cyclones for recirculate extraction, cyclones with a fan for dried product separation from used drier agent. According to the invention the separator is embedded into the tube drier between the ripper rotor and the cyclones; behind it, along the gas suspension flow path, a technological fan with controllable rotating frequency is placed; the separator is made in the form of holed concave grate located at a 10-30° inclination angle along the gas suspension flow path and is equipped at the end with a flap valve while the space under the separator is connected to the drying agent input nipple upstream the ripper rotor with a conduit the cross section area whereof is 5-15% of tube drier section.

EFFECT: performance increase, simplified regulation of the process of paste-like sticky products drying, product quality improvement and energy utilisation coefficient increase.

1 dwg

Description

The invention relates to food and processing industries and can be used in starch, alcohol and brewing for drying wet hydrophilic products.

A known method of drying high-moisture products, which involves moving a gas suspension through a divided pneumatic circuit of a recirculation dryer, in which the return of a large fraction of the product into the dryer pipe is carried out after drying in a mechanical grinder, and the return of the fine fraction is controlled using an additional fan after the end filter (Pat. 1037374 Germany, F26B, claimed 21.03.53, published 04.02.65).

The disadvantage of this method is the difficulty of adjusting the drying process of different-sized particles of sticky products of variable humidity and classification of recirculate and, as a result, low productivity.

The technical result of the invention is to increase productivity and simplify the adjustment of the drying process.

The technical result is achieved by the fact that in the method of drying high-moisture products, which involves moving a gas suspension through a divided pneumatic path of a recirculation dryer, returning a large fraction of the product to the dryer pipe after drying in a mechanical crusher and controlling the return of the fine fraction using an additional fan after the end filter, according to the invention, during the drying process in the pneumatic dryer tube, intermediate aerodynamic control of the separation of the drying agent flows is carried out a (drying agent) and suspended solids separation with pnevmotrakta recirculate, the amount, dispersibility and humidity recycle is controlled by changing the pressure difference between the values of the aerodynamic flow divided drying agent, depending on the humidity of the product at the outlet of the dryer. Isolated recycle is additionally classified with a fresh drying agent or sent to the zone of the most intense heat-mechanical processing of the product.

Known pneumatic dryers for starch and corn feed containing a feeder, rotary ripper, tube dryer, a separator or cyclones for returning the product to its original, cyclones with a fan for separating the dried product from the spent drying agent (Shamborant G.G. Technological equipment of starch-carrying enterprises industry. M: Light and food industry, 1984. - S.192, 196).

A disadvantage of the known dryers is a decrease in productivity if it is necessary to increase the amount of recirculate in the case of increased humidity and stickiness of the initial product, energy consumption for re-passage of the product through the pneumatic tube and drying of large particles, which ultimately, along with overheating of small particles, reduce the quality of the product.

The technical result of the invention is to increase productivity by reducing the amount of recirculated dried finished product, improving its quality and increasing the utilization of thermal and electric energy.

The technical result is achieved by the fact that the proposed installation for drying high-moisture products contains a feeder, rotor-ripper, pipe dryer, a separator for recirculate, cyclones with a fan to separate the dried product from the spent drying agent. In this case, the separator is built into the dryer pipe between the rotor-ripper and cyclones, and behind it, in the direction of the gas suspension, there is a technological fan with an adjustable speed. The separator is made in the form of a concave lattice with holes located with a slope of 10-30 ° along the gas suspension, and at the end is equipped with a flashing valve. A pipe for recirculating the drain from under the separator grate is connected to the pipe for supplying the drying agent in front of the rotor-ripper. The cross-sectional area of this pipeline is 5-15% of the cross section of the dryer pipe.

The invention is illustrated in the drawing.

The installation includes a mixer 1, feeder 2, rotor-ripper 3, heater of drying agent 4, pipe-dryer 5, recirculation pipe 6, separator 7 with flashing valve 8, fan 9 with variable speed, cyclone 10 and fan 11.

Installation works as follows. The feedstock — wet, liquid, and dried recycle products — is mixed in a mixer 1 and dosed by a feeder 2 into a rotary ripper 3, where it is dispersed in a stream of a drying agent coming from heater 4, and moves through a dryer pipe 5 through fan 9 to be deposited in cyclone 10. The undamaged crushed particles at the turn of the pipe 5 are discarded by centrifugal force to the separator 7, where, depending on the speed of the flow of the drying agent from the rotor-ripper 3 through the recirculation pipe 6, they are dried on a sieve e of the separator 7 or return to the zone of the most intensive material processing - to the rotor-ripper 3. Large particles that do not pass through the openings of the separator 7 are sent there by the flashing valve 8. The capacity of the process fan 9 is regulated depending on the humidity of the “dry” product at the outlet from cyclone 10 and, consequently, from the characteristics of the intermediate recirculate: with an increase in its moisture content and adhesion, the rotational speed of the fan 9 is reduced, as a result of which the pressure of the gas stream in front of it increases, that is, the vacuum in front of the fan 9 is reduced. In this case, the flow of the drying agent through the recirculation pipe 6 from the rotor-ripper 3 under the grate of the separator 7 weakens, the speed of this flow decreases, as a result of which the amount of recirculated through the separator 7 and the flasher valve 8 increases and vice versa. When the desired humidity of the “dry” product is reached, the rotational speed of the fan 9 is increased, the vacuum in front of it compared with the own vacuum of the rotor-ripper 3 and the flow of the drying agent through the recirculation pipe 6 increase, and coarse particles are predominantly dried with a fresh drying agent and their subsequent crushing by the fan blades 9, which along with this intensifies the vortex mixing of the product with the coolant and to some extent maintains the temperature azovzvesi by converting mechanical energy into heat. The fan 11 provides the movement of the gas suspension through the dryer and the removal of the spent drying agent.

The main technical advantages are as follows. The process fan 9 regulates the process of additional dispersion of the under-dried particles of the product both in the fan 9 and the intermediate recirculate in the rotor-ripper 3, as a result of which the surface of large particles is selectively activated, the evaporation of their capillary moisture is accelerated, the quality of the dried product is improved, the thermal product is more purposefully and economically used drying agent energy and electric energy to the unit drives. Due to this, the proposed dryers provide the processing of pasty sticky materials in a wide range of changes in their humidity, which is especially important for enterprises that process various products depending on the season.

Claims (2)

1. A method of drying high-moisture products, which involves moving a gas suspension through a separated pneumatic path of a recirculation dryer, returning a large fraction of the product to the dryer pipe after drying in a mechanical grinder, and controlling the return of the fine fraction using an additional fan after the end filter, characterized in that in the dryer pipe carry out an intermediate, aerodynamically controlled separation of the flows of the drying agent and suspended particles of the pneumotract with the separation of recirculate, while your dispersion and humidity of the recirculating product is controlled by changing the difference in aerodynamic pressure of the separated flows of the drying agent depending on the humidity of the product at the outlet of the dryer, and the recirculated product is additionally classified with a fresh drying agent or sent to the zone of the most intense heat-mechanical processing of the product. 2. Installation for drying high-moisture products containing a feeder, rotor-ripper, dryer pipe, a separator or cyclones for separating recirculated matter, cyclones with a fan for separating the dried product from the spent drying agent, characterized in that the separator is built into the dryer pipe between the rotor - a cultivator and cyclones, behind it in the direction of movement of the gas suspension there is a technological fan with an adjustable speed, while the separator is made in the form of a concave lattice with holes located with a slope of 10-30 ° in the direction of the gas suspension, at the end it is equipped with a flasher valve, and the separator sublattice is connected to the nozzle for supplying the drying agent in front of the rotor-ripper with a pipeline, the cross-sectional area of which is 5-15% of the cross section of the dryer pipe.