SU1581746A1 - Method of washing blast furnace hearth - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular to the domain production, can be used to monitor the state of the hearth and to carry out the hearth washing. The purpose of the invention is to increase the productivity of the furnace and reduce the consumption of coke due to the prevention of clogging up the hearth by conducting timely washes by introducing it into the mixture of washing additives such as welding and converter slags. The moment of introduction of wash additives into the mixture is determined by the difference between the current and threshold values of the thermochemical potential of the hearth, measured by electrodes, stabbed into the working layer of the hearth lining at two levels, the tuyere zone and the bottom, and forming pairs of thermoelectrodes producing EMF. Additives of the washing components are introduced into the charge with a decrease in the current value of the thermochemical potential below the threshold level. The amount of added additives is determined by the expression ΔM = BLN [V S (O) -V S (T)] @, where ΔM is the mass of washing additives introduced into the mixture, kg / feed

B is the coefficient characterizing the properties of flushing additives and design features of the furnace

V S (T) - the current value of thermochemical potential, mV

U S (O) - threshold value of thermochemical potential, mV

α is a binary coefficient taking values of 1 (for α = 1). 1 tab.

Description

The invention relates to ferrous metallurgy, in particular to the domain production, and can be used to monitor the state of the hearth and improve the operation of the blast furnaces by timely washing the hearth.

The aim of the invention is to increase productivity and reduce coke consumption by preventing clogging of the hearth by introducing washing additives into the charge in a timely manner.

The essence of the invention is as follows.

Using six pairs of insulated measuring electrodes insulated from the housing, stabbed into the working layer of the lining at the level of air tuyeres and on the floor, the EMF is measured and evaluated

The magnitude of the thermochemical potential of the hearth according to the formula (,

U

S (-t)

 Z gmU, ft /,

where g is the coefficient taking into account the material of the measuring electrodes; U. (t) - EMF arising in the i-th pair

measuring electrodes. The moment of entering the wash additives and the charge and their mass (3 t) is determined by the difference between the threshold (U5 (0j) and current values of the thermochemical potential of the hearth, using the expression:

Lt B. (ij-U3 (o) Da /, Where B is a coefficient depending on

the design features of the furnace and the properties of the used washing additives; g / is a binary indicator taking the value O or 1 depending on the conditions: -1 if Vs (i Us / o; if U S (|. The threshold value of the thermochemical potential of the hearth is found in the experimental way).

When the first signs of blocking appear, the magnitude of the magnitude starts to decrease, but the moment the Wash additives are introduced into the mixture is determined by the condition 5) (0) when.

Example. On a blast furnace with a volume of 1033 m3, 6 pairs of measuring electrodes from steel wire 010 mm were installed and connected to a multipoint potentiometer. For this furnace, the threshold value of the thermochemical potential of the forge, US (o) 48 mV, was experimentally set. As washing additives on the furnace, welding and converter slags were used, for which, under the conditions of this furnace, the coefficient is.

To control the heat load on the forge, differential thermocouples were simultaneously used on the furnace to measure the temperature drop of the cooling water at the inlet and outlet of the bottom coolers.

The results of measurements of the temperature difference on the bottom of the refrigerator, the thermochemical potential of the hearth, as well as the number of flushing additives and the time of their entry into the mixture, determined in accordance with the invention

five

0 5 0

five

about 5

d

five

This is presented in the table, which also shows the silicon content in the ho iron.

According to the experimental data obtained, a decrease in the thermochemical potential was observed already on the 6th release, and the threshold value was reached by the 11th release, which indicated the presence of the first signs of blockage of the hearth. By this time, the amount of heat removal not only did not decrease, but even increased as a result of a slight heating of the hearth on 1-5 outlets of pig iron. The blockage of the hearth by the temperature difference became noticeable only on the 15th issue, i.e. approximately 8-10 hours after the appearance of its first signs. Washing the hearth in accordance with thermocouple readings controlling heat removal from the bottom refrigerators would require more washing additives and additional coke consumption.

The timely introduction of flushing additives made it possible to prevent the development of blockage of the hearth, while maintaining the intensity of smelting and the sulfur content in the iron within the specified limits. The magnitude of the thermochemical potential of the hearth stabilized 20 hours after the discovery of the first signs of hearth blockage and the introduction of washing additives into the mixture.

The application of the invention allows to maintain the active operation of the hearth in the fluctuations of thermal and slag melting modes, to increase the productivity of furnaces by 1.4% and to reduce the consumption of coke by 0.8%.

Claims (1)

Invention Formula The method of washing the hearth of a blast furnace, including determining the indicators of the heat load of the hearth and introducing washing additives into the mixture, characterized in that, in order to increase furnace productivity and reduce coke consumption, the thermochemical potential of the furnace is measured and the amount of washing additives added to the mixture is determined by dependencies 4t In IntUsfo) - US (t) 3, where it is the number of flushing additives, kg / feed; 31581746 - coefficient of proportionality, taking into account the material additives, kg / feed-mV; us (tj threshold value of thermo- the potential of the mountain, Mbf current value thermochemistry-. the potential of the hearth, mV; binary indicator.  Start entering into the mixture of washing additives.