SU1562641A1 - Fluidezed-bed drier - Google Patents

Abstract

The invention relates to heat and mass transfer apparatus and can be used in the development of drying equipment used in the chemical, food and other industries. Improving the quality of drying can be achieved by placing heat pipes above the gas distribution grid. Moreover, the horizontal evaporation zones 8 of the pipes are arranged in two rows symmetrically to the axis of chamber 1, and the condensation zones 7 are vertically with the formation of a funnel 10, along the axis of which is placed the top of the feeder 14, below the nozzle distributor 3. 1 zp. f-ly, 2 ill.

Description

1

The invention relates to heat-1 and mass transfer devices and can be used in the development of drying equipment used in the chemical, food and other industries.

The purpose of the invention is to improve the quality of drying at the location of the duct for the supply of coolant under the entire area of the gas distribution grid.

FIG. 1 schematically shows the proposed dryer; in fig. 2 shows section A-A in FIG. one.

The dryer contains a chamber 1, in the lower part of which a gas distribution grid 2 2 is installed.

In the middle part of the gas distribution grid 2, along all its length, a nozzle distributor 3 of heat transfer medium is made, closed by a grid 4 with a large living section. A fluidized bed 5 of the dried material is placed on the gas distribution grid 2, and inside the fluidized bed 5, heat pipes 6 are installed on both sides of the distributor 3 symmetrically relative to the axial plane of chamber 1, and the condensation zones 7 of the heat pipes are directed in opposite directions. In addition, the evaporation zones 8 of the heat pipes 6 are placed in the grid 10 along the gas distribution grid 2 in two rows with the formation of a funnel 10, the opposite sides 11 of which have longitudinal slots 12. The angle between the condensation zones 7 of the heat pipes 6 can be chosen in the range of 50-90. Heat pipes 6 are attached with the help of holders 13 to the walls of the drying chamber 1. On the ceiling of the drying chamber 1 coaxially with the nozzle 3, a feeder (loading device) 14 is installed, and in the grid 10 - a discharge device 15.

The fluidized bed dryer works as follows.

Dry product granules are preloaded into the drying chamber 1. The gas is distributed through the gas distribution grid 2 and the distributor 3 is supplied with hot coolant, and from above the fluidized bed 5 is fed with a feeder 14 raw material granules. In this case, the crude product enters the space between the capacitor zones 7

heat pipes 6 with the zone of action of the jet of heat-transfer fluid leaving the nozzle distributor 3. Due to the high velocity of the hot heat-transfer fluid, the raw granules are pre-dried with simultaneous dusting with dry dust fractions. Since the slots 12 of the funnel 10 between the heat pipe capacitors are small (2-5 medium diameters of the granules), the raw product undergoes processing for some time inside the funnel 10 in the mode of the flowing layer.

The evaporation zones 8 of the heat pipes 6 are in the inflow zone 9, where at a height of 15-30 mm from the gas distribution grid 2 the temperature of the drying agent decreases from its maximum value to the temperature of the flue gases. Due to the high temperature of the drying agent, the working fluid evaporates inside the evaporation zones 8, the vapor is transported and then condenses in the condenser zones 7. Thus, part of the heat is transferred by heat pipes 6 from the inflow zone 8 to the upper part of the fluidized bed 5. For processes heat exchange with surfaces in a fluidized bed is characterized by high values of heat transfer coefficients.

Taking into account that heat transfer from the inflow zone 9 is carried out by heat pipes 6 at high values of heat exchange coefficients, the process of drying thermosensitive materials can be significantly intensified due to the use of 1 drying agent with increased temperature without danger of product damage, as part of the heat is transferred by specified thermal pipes. The heat transported by the heat pipes 6 is transferred from the condenser zones 7 to both the raw material s processed in the spout in the funnel 10 and to the dried product in the remaining part of the fluidized bed.

In the proposed dryer, the jet of coolant leaving the distributor 3 ensures the directional circulation of the product in the drying chamber. The product particles ejected to the plume root above the nozzle distributor 3 are transported from the walls of the drying chamber 1, the passage being heat-treated in the high-temperature grid around the grid. Accordingly, in the near-wall zone of the fluidized bed 5, as well as in the fluidized bed 5 itself, there is a downward movement of the particles of the dried product. Above the nozzle distributor 3, the material moves upward, descending downward along the rows of condenser zones 7, and through the slits 12 there are particle flows both into the plume zone above the nozzle distributor 3 and in the opposite direction.

Claims (2)

1. A fluidized bed dryer containing a chamber with a loading device in the upper part, a gas distribution grid and heat pipes with five 0 zonal evaporation zones located above the grille and heat transfer media box, which is equipped with a taxiway so that, in order to improve the quality of drying when the heat transfer supply box is located under the whole distribution grid of the gas distribution grid, the evaporation zones of heat pipes are installed two rows symmetrically to the chamber axis, and their condensation zones are located at an angle to the vertical and directed in opposite directions with the formation of a top with longitudinal slots on two opposite sides, while the loading point The device is located along the axis of the camera. 2. Dryer according to claim 1, characterized in that a nozzle distributor of the heat transfer medium is additionally installed along the axis of the grate. FIG. 2