SU1028993A1 - Method of automatic control of roasting process in multizone furnace with fluidized bed - Google Patents

Abstract

A METHOD FOR AUTOMATIC REGULATION OF THE BURNING PROCESS IN A MULTI-ZONE FURNACE WITH A BOILING LAYER, including measuring the temperature in the bed. And above the bed of the burning zone and maintaining the temperature in the bed according to their difference, characterized in that, in order to reduce furnace downtime due to overgrowing of the bottom zone, The temperature under the grate of this zone is additionally measured and it is regulated at a predetermined level by removing part of the heat of the firing gases from the over-layer space of the firing zone, and the amount of heat removed changes the proportion ionalno deflection temperature under (A lattice from the given. jisd 00 to 00

Description

The invention relates to the regulation of technological processes of roasting in furnaces with a fluidized bed (CS) and can be used in ferrous and nonferrous metallurgy, in the industry of building materials and other industries.

There is a known method of automatic control of the roasting process in the KS furnaces by changing the feed of the raw material to the roasting zone depending on the variation of the temperature of the fluidized bed in this zone from a predetermined value.

However, the known sporob does not ensure the qualitative regulation of the temperature in the layer due to a significant delay in the measurement result.

The closest to the present invention is a method of controlling the firing process in KS furnaces by changing the feedstock feed to the firing zone according to the temperature difference in the layer and above the layer of this zone 1G2.

Due to the decrease in the measurement inertia, it allows to substantially eliminate the indicated disadvantage of the previous method, but does not stabilize the temperature under the grate of the lower heating zone when the temperature changes in the firing zone layer. For example, as the temperature in the layer increases, the temperature under the lattice increases accordingly.

The need to change the set temperature in the layer can be caused by various technological reasons: the change in the particle size distribution of the raw material, the maintenance of the given furnace productivity, the quality (degree) of firing of the material, etc.

At the same time, the temperature under the grill of the lower heating zone should be stabilized at a given level, since its excess leads to the growth of the lattice of this zone and, as a result, to frequent stops and prolonged simply m furnace, So, when the temperature in the sublattice area rises 1100-1150 C begins the process of adhering fine, highly active dust in the holes of the bottom.

An increase in the firing temperature is caused by the following contradiction: on the one hand, an increase in the heat supply to the firing zone layer, i.e. an increase in the temperature in the bed allows an increase;

{with other things being equal: feedstock and degree of calcination of the material), the furnace capacity, and hence the production volume, on the other hand, increases accordingly in the above-layer space of this zone (due to the equal temperature of the material on the surface of the fluidized bed) and the environment heat, and hence the temperature under the grill of the lower heating zone, which leads to the rapid overgrowth of the lattice openings, disruption of the hydrodynamic operating mode of the furnace and its forced stoppages, reducing the production volume properties.

At stops and subsequent start-ups of the furnace, large additional heat losses are inevitable. The labor costs for cleaning the grate are also great. All this reduces the technical and economic performance of the unit.

. The purpose of the invention is to reduce furnace downtime due to the overgrowing of the grate of the lower preheating zone.

This is achieved in that according to the method of automatic control of the firing process in a multi-zone furnace: with a fluidized bed, the temperature under the grate of this zone is measured and controlled at a predetermined level by removing part of the heat of the firing gases from the superlayer space of the firing zone, and the amount The recoverable heat is changed in proportion to the deviation of the temperature under the grate from the set one.

The drawing shows an example of the implementation of the proposed method.

The technical solution contains the following equipment: a multi-zone fluidized bed furnace 1 consisting of two heating zones and a firing zone, a heat exchanger, 2 tails of heat from the over-layer space of the firing zone, supplying the pipe line 3 to the heat exchanger with a control valve and water conduit 5, pipelines 6 and 7, respectively, of fuel and air supplied to the combustion, the gas exhaust path of the furnace 8, the overflow device 9, the overflow device 10 with a regulating valve 11, temperature sensors in the layer 12 and above the layer 13 of the zone b) Yigal, k setpoint regulator 15 and the temperature in the layer of the burning zone, the actuator 16 articulated with

valve 11 downstream device; temperature sensor 17 under the grill for lower heating of the knob 18 K of controller 19 temperature under the grille, actuator 20 coupled to the peryjiMpyioiiiHM valve: 4 flow rates of cooling agent through: heat exchanger.

: The method is carried out in the following manner. . ,

When changing, for example, uvepichnii: the temperature in the zone of firing, firing, respectively, increases the temperature under the grill of the lower heating zone. The temperature is measured by a sensor 17. whose signal at the input-re-; gullet 19 is equal to the temperature setting signal & T8.i T.i Depending on the size of the regulator, the regulator acts on the control valve L through the actuating mechanism 20, proportionally increasing | 1. the flow rate of the cooling agent through the heat exchanger i, and keeps the heat sink under the grille at the preset level. ; -: -, -; „.,:.:. This option is determined by the increase in the production volume for C4et secret | e-; no stoppage downtime and fuel savings due to a decrease. heat to heat the furnace when starting. one

The annual economic effect of the 1000 t / day furnace is approximately 100 thousand ()

Claims (1)

METHOD FOR AUTOMATIC REGULATION OF THE FIRING PROCESS IN A MULTI-ZONE FURNACE WITH A BOILING LAYER, including measuring the temperature in the layer and above the layer of the firing zone and maintaining the temperature in the layer according to their difference, characterized in that, in order to reduce the furnace downtime due to overgrowing of the grate of the lower heating zone, additionally measure the temperature under the grate of this zone and regulate it at a predetermined level by removing part of the heat of the calcining gases from the superlayer space of the calcining zone, and the amount of heat removed is changed proportionally Temperature of deflection under a given lattice. SU, „. 1028993 1 10ZO993 2