SU901309A1 - Method of thermal condition control in hearth of annealing conveyer machine for thermal treatment of pellets - Google Patents

Description

(54) METHOD FOR REGULATING THE HEAT MODE IN THE MOUNTAIN

The invention relates to the agglomeration of iron ore raw materials and can be used to regulate the thermal conditions in the furnaces of the calcining conveyor machines when burning fuel and burning air, and diluting the combustion products with a high-temperature heat carrier. There is a known method of controlling the thermal conditions in the furnaces of roasting conveyor machines, which consist in maintaining fuel and nausea ratios, fuel to air for burners serving opposite prechambers, and controlling the temperature in the mountain sections. It is carried out b & g accounting of the products of combustion flowing from one section of the hearth to another. However, the disadvantage is that the application of the known method on modern kiln machines, which carry a high-temperature heat transfer fluid through the discharge collector through the prechamber, is fed into the furnace,

Rounding up with the difficulties of establishing and stabilizing. Lizapia in the furnace of the burning machine of a given thermal regime. The closest to the proposed technical essence is the method of regulating the thermal regime in the zones of heating and calcining of the hearth of the calcining conveyor machine, which consists in individually controlling the temperature in each (part of the hearth with a pair of opposite burners). In each section, the temperature is measured with dual thermocouples on each side of the zone, the signal from one of the thermocouples on one side is fed to a multipoint recorder with contacts SignalBazagga of the upper right and temperature. Another element of the same thermocouple, together with a pair of opposite-side thermo pairs, is used to obtain the average temperature of the segosh as the measured temperature as a pulse or control. The setting of the temperature regulators is set manually and the temperature is maintained automatically flue gas. To regulate cooler gas-air regulators, one for each pair of burners, c. Depending on the flow rate, the air flow is changed. 23 The disadvantage of this method is that the loss of heat carrier through a layer in different lengths of the furnace sections is not taken into account, because of the flow of combustion products from one section of the furnace to another, as well as the temperature in the sections of the furnace, the requirements for obtaining quality products are different, then the flows increase the time required for the establishment in the furnace of a given thermal regime and the difficulties associated with its stabilization. The purpose of the invention is to improve the quality of regulation of a given tagging mode in the furnace and reduce fuel consumption per process. This goal is achieved by the fact that in the method of controlling the thermal conditions in the furnace, the annealing conveyor machine for heat treatment of pellets. including individual control of the desired temperature in each section by changing the fuel and air consumption at the burner, the air consumption for combustion in the hearth sections is set proportional to the square root of the absolute temperature of the combustion products in these sections, and the high-temperature heat carrier costs are proportional costs: products of combustion, which are sucked through a layer of pellets in the same sections of the hearth. This is done by distributing the combustion air over the sections of the hearth proportional to the square root of the absolute temperature of combustion products in these sections, i.e. with respect to VieV.A where V is the flow rate of combustion air in the i-th section, T is the absolute temperature in the 1st horn section, K. The distribution of combustion air over the sections of the horn, using the proposed ratio, allows the high-temperature coolant to be distributed, which is 70-8O%, proportional to the flow rate of the combustion products through the horn sections and, traces tion, to reduce combustion products flows from one section of the hearth to another. FIG. 1 is a schematic diagram of the operation of the hearth of the roasting machine, FIG. 2 - temperature change over a layer of pellets along the length of the hearth; in fig. 3 - change in air consumption for combustion along the length of the forge; in fig. 4 - change. combustion products, sucked through a layer along the length of the forge; in fig. 5 shows the change in the high-temperature heat-transfer agent along the hearth in FIG. b - changes in the flow of products of the bunch from one section 3 to another for different sections along the length of the hearth. The high-temperature coolant from the cooling zone through the overflow collector 1 and the pre-chamber 2 enters the furnace burner 3, and the air for combustion and natural gas enters the furnace through the burners 4. The temperature of the combustion products (FIG. 2) 3) and natural gas in the hearth sections are regulated by the indications of stationary instrumentation. The consumption of combustion products sucked through a layer of pellets (Fig. 4) depends on the quality of the raw material. roasting machine performance and smoke exhauster operation. The flow rate of the high-temperature heat-transfer agent (Fig. 5) depends on the air consumption for combustion and the combustion products sucked through the bed in the sections of the hearth. According to the proposed method, the ratio of the flow rates of combustion air in the hearth sections is established. Solid lines / show the change in temperature above the bed, the air consumption for combustion, the combustion products drawn through the bed, the high-temperature heat transfer fluid in this mode of operation of the hearth when controlled by the proposed method. In the field of changing the same values, their changes when the furnace is operated in different modes and when the heat flow rate deviates from the suggestions of the method, the proportionality of the distribution of the costs of the high-temperature heat carrier to the consumption of the combustion products along the length of the hearth is disturbed. From the comparison of the flows of prodztstov combustion between the sections of the hearth (Fig. 6)

an increase in their volume with a deviation in the regulation of the thermal regime in the furnace of the roasting machine from the proposed method (continuous line).

The total air flow on, the products of combustion through the layer, high-temperature coolant in s PIEIN horn (Fig. 2). tabulated.

The desired temperature in the sections is kept by a known method by varying the amount of fuel supplied;

Reducing the flow of combustion products from one section of the hearth to another, the autonomy of regulating the thermal regime in the sections of the forges of roasting conveyor machines ensures an improvement in its quality and a reduction in fuel consumption per process.

The introduction of the proposed method of controlling the thermal conditions in the furnaces of calcining conveyor machines for processing pellets directly on the SZh-52O roasting machine allows reducing the consumption of natural gas by 0.4 m / t of pellets and improves the quality of the finished product.

Claims (2)

1. Gosenbuk LG, Ksenzovsky VR, and others. Bulletin of TsNIITEICHM, 1969, No. 2, p. 19-22 ... 2., Canadian Mining Zogpab. 197O 91, N9 Il; p. 94-95. / Vrzduu. MO burning Pkg.1 f i bUJ.U il Cws “S. twH + o H b 43