RU2039332C1 - Method of controlling cooling of metallurgic furnace water jacket - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: parameters of main flow of coolant are measured. The values obtained are compared with given extreme values. When the values obtained exceed given ones, additional coolant is supplied resulting in dynamical control of cooling of the furnace water jackets depending on the amount of temperature time increment. The temperature increment can be judged by comparing it with the reference value of the increment. EFFECT: enhanced reliability. 2 dwg

Description

 The invention relates to metallurgy and can be used in metallurgical processes, mainly in non-ferrous metallurgy.

 A known method of controlling the cooling of the caissons of metallurgical furnaces due to the fact that they measure the parameters of the main coolant flow at the outlet of the caissons, compare the obtained parameters with the specified limit values, and when these limit values are exceeded, an additional liquid stream is fed into the overheating caissons.

 The disadvantage of this method is that when controlling the temperature regime does not take into account the dynamics of heating, and fixed its limit value.

Thus, for a fixed limit value, e.g., t = ⁶⁰ ° C, at this temperature an additional stream once fed. With slow heating with an additional supply of liquid, the walls undergo supercooling quickly, when the flow is switched off, heating again, etc. Changes in the temperature regime affect the strength of the caissons, the stability of the formation of the skull in the wall layer, which affects the performance of the process.

 The proposed method aims to eliminate these disadvantages.

 The aim of the invention is to provide smooth temperature control by proactively supplying increased coolant flow rates to an overheating caisson, preventing the caissons from “steaming” and breaking them, preventing emergency stops of the furnace and optimizing the process.

и сравнивают его с контрольным значением

контр. за тот же промежуток времени и при значении

≥

контр. осуществляют подачу дополнительного потока, а при

<

контр. подачу дополнительного потока осуществляют при температуре (0,55-0,6)t_кип.The goal is achieved in that the pre-empt the increased coolant flow rate in the overheated caisson, which set the boundary regulation temperature equal to the boiling point of t 0.5-0.55 _heated at a working pressure of coolant in the caisson, towards which at predetermined time intervals Δ τ measure the temperature increment over time

and compare it with the control value

counter. for the same period of time and at

≥

counter. supply an additional flow, and when

<

counter. the additional flow is carried out at a temperature of (0.55-0.6) t _bales .

Below the boundary temperature (0.5--0.55) t _bale. an additional stream is disabled.

 The choice of the range of regulation boundaries is due to the following factors.

 Qualitative control of the temperature regime of the installation is carried out based on the nature of the temperature of the water leaving the cooled elements.

 The normal temperature regime of melting is characterized by the formation of an annular nastily in the mouth of the tuyere. This accretion builds up within 1-2 minutes, and then spontaneously breaks down by a stream of blast.

Water control temperature equal to (0.55-0.6) t _bale. corresponds to the melting mode with the formation of ring accretions, because the complete absence of accretions indicates an excessively hot process.

The boundary control temperature for water is (0.5-0.55) t _bale. corresponds to the regime with the formation of a stable coating, indicating a cold process.

 In FIG. 1 shows a graph of the dynamics of temperature conditions in the caissons of a metallurgical furnace using the example of a “PV” process; in FIG. 2 control algorithm for cooling the caissons of metallurgical furnaces.

On the graph, the melting process takes place at normal operating temperature t _slave. curve 1.

 Under the influence of external causes of changes in the feed and composition of the charge, oxygen supply, etc., the temperature in the furnace rises and, consequently, the temperature of the coolant in the caissons rises.

 In accordance with the prototype, the adjustment begins after reaching the maximum temperature value exiting the caisson liquid. This limiting value is determined from the condition of protection of the walls of the caisson from the melt, i.e. the presence of a skull of a certain thickness.

 Suppose that the value of the limiting temperature in the prototype coincides with the value of the boundary temperature of regulation in the invention (which is natural, since the melting conditions are the same).

Taking into account the pressure of the liquid inside the caisson and the corresponding boiling temperature, we determine the limiting temperature value equal to (0.6-0.65) t _bales . Without taking into account the dynamics of heating, at point 2 'at time 2'', an additional supply of liquid is turned on, and the cooling process proceeds along curve 2, i.e. close to emergency mode may be created. Then change the flow of the charge and oxygen.

 Another option is also possible when the heating process proceeds near the limiting temperature and then can self-regulate without additional supply, which can lead to overcooling of the walls and the formation of a thick layer of a skull plate instead of use.

The control method according to the invention allows to take into account the dynamics of heating the liquid. To do this, choose a boundary temperature lower than in the prototype and equal to (0.5-0.55) t _bales .

и сравнивают его с контрольным значением

контр. прямая "К". Если

≥

контр. включают увеличенную подачу жидкости в точке 3', которая упреждает перегрев кессона, и охлаждение происходит плавно, переходя к рабочему режиму.When the boundary temperature is reached, point 3 'at predetermined time intervals Δ τ, sec measure the temperature increment

and compare it with the control value

counter. direct "K". If

≥

counter. turn on the increased fluid supply at the point 3 ', which prevents the overheating of the caisson, and cooling occurs smoothly, passing to the operating mode.

<

контр. охлаждение дополнительное не включают. Если же температура нагрева дойдет до уровня предельной температуры (как в прототипе), то включение произойдет в точке 4', опасность большого перегрева невелика, поскольку динамика нагрева спокойная кривая 4, а возможен вариант, когда включение не потребуется из-за саморегуляции процесса кривая 5.If

<

counter. additional cooling does not include. If the heating temperature reaches the limit temperature level (as in the prototype), then switching on occurs at point 4 ', the risk of large overheating is small, since the heating dynamics are calm curve 4, and it is possible that switching on is not required due to the process self-regulation curve 5 .

 Thus, the reliability of the furnace increases, the campaign of the furnace increases, the process is optimized.

 The method of controlling the cooling of the caissons of metallurgical furnaces is implemented by the algorithm (Fig. 2).

контр. контрольное значение приращения температуры во времени.In accordance with the subject invention, initial parameters are introduced
t ' _gr boundary control temperature equal to (0.5-0.55) t _bale. ;
t '' _g second boundary temperature equal to (0.55-0.6) t _bale. ;

counter. control value of the temperature increment in time.

 During the operation of the furnace, the current temperature t is constantly measured.

If t <t ' _gr. pump (flow) optional is turned off.

контр.At t≥t ' _gr. measured at intervals Δ τ increments of temperature Δt and compare it with the control value

counter.

≥

контр. включается дополнительный насос (поток воды).At

≥

counter. an additional pump is switched on (water flow).

<

контр. дополнительный насос включается при t≥t''_гр, а при t<t''_гр и t>t'_гр производится контроль

при t<t'_гросуществляется нормальный текущий замер температуры t.At t≥t ' _gr , but

<

counter. the additional pump is switched on at t≥t '' _gr , and at t <t '' _gr and t> t ' _gr

at t <t ' _gr normal current temperature measurement t is carried out.

 PRI me R implementation of the method.

Initial data:
1. Pressure in caissons 3 at. 294, 2 kPa.

2. t boiling water at a given pressure t _boiling. 132.88 ^о С (see H. Kuhling "Handbook of Physics". M. Mir, 1982, pl. 24 ^a , p. 467).

контр.

1/60 град.сек

В данном примере контрольное значение выбрано на основе опыта эксплуатации печи ПВ на одном из комбинатов цветной металлургии.3. Boundary temperatures
0.5 t _bales 64.4 ^about With
0.55 t _bales 73 ^about With
0.6 t _bale 79.7 ^about C
4. The control value of the increment

counter.

1/60 deg. Sec

In this example, the control value is selected based on the operational experience of the PV furnace at one of the non-ferrous metallurgy plants.

 Process management.

Melting is carried out at a working temperature of water leaving the caissons about t _slave. 55-60 ^about S.

, что больше контрольного 1град/60 сек, включается дополнительная подача жидкости, с расходом в 2-5 раз выше нормального.The water temperature in the caisson is increased when reaching 64.4 ^{° C} starting temperature measured every 60 seconds. If the current increment value, for example, within 180 seconds, will show

, which is more than the control 1 grad / 60 sec., an additional fluid supply is switched on, with a flow rate 2-5 times higher than normal.

<

контр. подача дополнительной жидкости должна осуществляться в промежутке температур 73^о-79,7^оС.Provided that the heating is on curve 4 (Fig. 1), i.e.

<

counter. the supply of additional fluid should be carried out in the temperature range 73 ^about -79.7 ^about C.

 It should be noted that the indicated temperature limits relate to cooling the caissons with chemically purified water, the quality of which is determined by OST 108.34.02-79 of the Ministry of Energy.

 When cooling with industrial water, as well as when changing the operating conditions of the caissons, the boundary limits must be adjusted, which does not affect the technical solution regarding the method of controlling cooling of the caissons.

состоит в том, что составляется тепловой баланс процесса плавки промышленного комплекса ПЖВ с учетом конкретных условий, с последующим уточнением технологических параметров в период освоения. Приведенные усредненные числовые данные соответствуют опыту эксплуатации на Балхашском и Норильском ГМК.The methodology for determining the control parameters Δ τ, sec and

consists in compiling the heat balance of the smelting process of the industrial ПЖВ complex taking into account specific conditions, with the subsequent refinement of technological parameters during the development period. The presented average numerical data correspond to the operating experience at the Balkhash and Norilsk MMCs.

 For other types of materials, new calculations must be performed and the obtained parameter values entered into the regulation system.

Claims (1)

METHOD FOR CONTROLING COOLING OF A METALLURGICAL FURNACE CESSON, including measuring the temperature of the main coolant flow in the caisson, comparing the measured temperature with the limit set by the technology and supplying an additional fluid flow to the caisson when the measured temperature exceeds the limit value, characterized in that, in order to increase reliability furnace operation, when the coolant temperature value in the caisson 0.5 0.55 boiling temperature value (t _{k and n)} cooling liquid minute at a working pressure at predetermined technology intervals (Δτ) is determined increment coolant temperature (Δt / Δτ), comparing it with a value (Δt / Δτ) specify the technology _counter for the same interval of time and at a (Δt / Δτ) ≥ (Δt / Δτ) _counter serves an additional flow of cooling liquid to the caisson, at (Δt / Δτ) <(Δt / Δτ) the _counter flow is supplied when the temperature of the main stream reaches (0.55 0.6) t _{k and item} .

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