Method for increasing converter dry dedusting coal gas recovery heat value

Abstract

The invention discloses a method for increasing a converter dry dedusting coal gas recovery heat value, and relates to the technical field of dry dedusting, and the method comprises the following steps: S101, setting and executing a static rotating speed of a dry dedusting fan; step S102, judging whether the converter is currently in a blowing period or not, if not, performing a step S103, and if yes, performing a step S104; s103, the static rotating speed, set in the step S101, of the dry dust removal fan is kept; and S104, reading the target value of the inlet pressure of the evaporative cooler, and automatically adjusting the speed of a dry dust removal fan. According to the method, the converter dry dedusting coal gas recovery heat value is effectively increased, investment and time are saved, the effect of getting effect instantly can be achieved, and the energy-saving and emission-reducing benefits are remarkable.

Description

Technical Field

[0001] The invention relates to the technical field of dry dust removal, and in particular to a method for improving the calorific value of dry dust removal coal gas recovered from a converter. Background Art

[0002] The converter dry dust removal technology is an effective way to achieve ultra-low emissions in converter steelmaking and has been widely used at home and abroad. However, in order to control the explosion of the dry dust removal system, especially the explosion of the electrostatic precipitator, the blowing period generally adopts the method of increasing the air intake at the furnace mouth and increasing the combustion of CO to generate CO2, which leads to a short converter gas recovery time, low CO concentration, and low calorific value, which in turn results in a small amount of effective converter gas recovered. Converter gas recovery is a key link in achieving "negative energy steelmaking" and is one of the two types of energy recovered during smelting. The effective gas recovery amount calculated by calorific value is the core indicator of energy conservation and emission reduction in the converter steelmaking link. Therefore, it is particularly important to improve the calorific value of converter dry dust removal gas recovery. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the disadvantages of the prior art and provide a method for improving the calorific value of the dry-dust-removed converter coal gas.

[0004] In order to solve the above technical problems, the technical solution of the present invention is as follows: A method for improving the heat value of converter dry dust removal gas recovery, comprising the following steps: Step S101: setting the static speed of the dry dust removal fan and executing; Step S102: determine whether the converter is currently in the blowing period, if not, proceed to step S103, if yes, proceed to step S104; Step S103: maintaining the static speed of the dry dust removal fan set in step S101; Step S104: Obtain the deviation between the actual pressure value at the evaporative cooler inlet and the target value. If the actual pressure value at the evaporative cooler inlet is less than the target value and the deviation is greater than the preset value, reduce the speed of the dry dust removal fan. If the actual pressure value at the evaporative cooler inlet is greater than the target value and the deviation is greater than the preset value, increase the speed of the dry dust removal fan. If the absolute value of the deviation between the actual pressure value at the evaporative cooler inlet and the target value is less than the preset value, maintain the static speed of the dry dust removal fan set in step S101.

[0005] As a preferred solution of the method for improving the heat recovery value of converter dry dust removal gas according to the present invention, the target value of the inlet pressure of the evaporative cooler is increased by 50Pa after blowing for 2 minutes.

[0006] As a preferred solution of the method for improving the heat recovery value of converter dry dust-removed coal gas described in the present invention, the preset value is 10Pa.

[0007] As a preferred solution of the method for improving the heat recovery value of converter dry dust removal gas described in the present invention, the static speed of the dry dust removal fan is 10-16 gears.

[0008] The beneficial effects of the present invention are: (1) The present invention reads the target value of the evaporative cooler inlet pressure according to the blowing time, automatically adjusts the speed of the dry dust removal fan, and controls the deviation between the evaporative cooler inlet pressure and the target value within a certain range. In this way, more air is inhaled into the furnace mouth within 2 minutes of blowing, which can accelerate the combustion of CO to generate CO2 and effectively avoid the explosion relief interval of CO>9% and O2>6%. After 2 minutes of blowing, the furnace mouth is basically maintained at a slightly positive pressure, reducing air intake, accelerating the rate of increase in CO concentration and decrease in O2 concentration, effectively advancing the time for qualified recovery of converter gas, and at the same time increasing the CO concentration in the recovery period and reducing the CO2 concentration, thereby effectively increasing the calorific value of converter gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0010] Figure 1 A schematic flow chart of a method for improving the calorific value of dry-dust-removed converter gas provided by the present invention. DETAILED DESCRIPTION

[0011] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific implementation modes and in combination with the accompanying drawings.

[0012] Figure 1 A flow chart of a method for improving the heat value of dry-dust-removed converter gas recovery provided in an embodiment of the present application. The method specifically comprises the following steps: Step S101: setting and executing the static speed of the dry dust removal fan.

[0013] Specifically, the static speed of the dry dust removal fan is generally divided into 10 to 16 gears.

[0014] Step S102: Determine whether the converter is currently in the blowing period, if not, proceed to step S103, if yes, proceed to step S104.

[0015] Specifically, the working condition of the converter and the current operation state of the converter are obtained to determine whether the converter is currently in the blowing period or the non-blowing period. If the converter is currently in the non-blowing period, step S103 is executed; if the converter is currently in the blowing period, step S104 is executed.

[0016] Step S103: maintaining the static speed of the dry dust removal fan set in step S101.

[0017] Specifically, when the converter is in the non-blowing period, the static speed of the dry dust removal fan set in step S101 is directly maintained.

[0018] Step S104: Obtain the deviation between the actual pressure value at the evaporative cooler inlet and the target value. If the actual pressure value at the evaporative cooler inlet is less than the target value and the deviation is greater than the preset value, reduce the speed of the dry dust removal fan. If the actual pressure value at the evaporative cooler inlet is greater than the target value and the deviation is greater than the preset value, increase the speed of the dry dust removal fan. If the absolute value of the deviation between the actual pressure value at the evaporative cooler inlet and the target value is less than the preset value, maintain the static speed of the dry dust removal fan set in step S101.

[0019] Specifically, when the converter is in the blowing period, based on the static tachometer executed according to the blowing time, the target value of the evaporative cooler inlet pressure is read and the speed of the dry dust removal fan is automatically adjusted, as follows: If the actual pressure value at the evaporative cooler inlet is greater than the target value, and the deviation is greater than the preset value, the fan speed is controlled to increase; If the actual pressure value at the evaporative cooler inlet is less than the target value, and the deviation is greater than the preset value, the fan speed is controlled to decrease; If the absolute value of the deviation between the actual pressure value at the evaporative cooler inlet and the target value is less than the preset value, the fan speed is controlled to remain unchanged.

[0020] In this embodiment, the above preset value is 10Pa. That is: If the deviation between the evaporative cooler inlet pressure and the target value (actual pressure value - target value) is >10Pa, the fan speed increases; If the deviation between the evaporative cooler inlet pressure and the target value (actual pressure value - target value) is less than -10Pa, the fan speed is reduced; If the deviation between the evaporative cooler inlet pressure and the target value (actual pressure value - target value) is within the range of ±10Pa, the fan speed remains unchanged.

[0021] It should be noted that the target value of the inlet pressure of the evaporative cooler is inversely proportional to the blowing time.

[0022] In this embodiment, after 2 minutes of blowing, the target value of the inlet pressure of the evaporative cooler increases by 50 Pa. During the converter blowing, the target value of the inlet pressure of the evaporative cooler is set according to the blowing time. Generally, the target value within 2 minutes of blowing is about 50 Pa higher than that after 2 minutes, such as 10 Pa within 2 minutes of blowing and 60 Pa after 2 minutes of blowing.

[0023] According to the blowing time, the target value of the evaporative cooler inlet pressure is read, and the speed of the dry dust removal fan is automatically adjusted to control the deviation between the evaporative cooler inlet pressure and the target value (target value - actual pressure value) within a certain range, such as ±10Pa. In this way, more air is inhaled at the furnace mouth within 2 minutes of blowing, which can accelerate the combustion of CO to generate CO2 and effectively avoid the explosion relief interval of CO>9% and O2>6%; after 2 minutes of blowing, the furnace mouth is basically maintained at a slightly positive pressure, reducing air intake, accelerating the increase in CO concentration and the decrease in O2 concentration, effectively advancing the time for qualified recovery of converter gas, and at the same time increasing the CO concentration during the recovery period and reducing the CO2 concentration, effectively increasing the calorific value of converter gas.

[0024] It should be noted that the control of the above method for improving the heat value of the recovered gas from the dry dedusting of the converter is implemented in the control system such as PLC and DCS, and the static speed and the target value of the evaporative cooler inlet pressure are set on the HMI screen.

[0025] Therefore, the technical solution of the present application realizes the effective improvement of the calorific value of the recovered gas from the dry dust removal of the converter, which not only saves investment and time, but also has an immediate effect, and the energy-saving and emission-reduction benefits are also significant.

[0026] In addition to the above embodiments, the present invention may also have other implementation modes; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A method for improving the heat value of converter dry dust removal gas recovery, characterized in that: The following steps are involved: Step S101: setting the static speed of the dry dust removal fan and executing; Step S102: determine whether the converter is currently in the blowing period, if not, proceed to step S103, if yes, proceed to step S104; Step S103: maintaining the static speed of the dry dust removal fan set in step S101; Step S104: Obtain the deviation between the actual pressure value at the evaporative cooler inlet and the target value. If the actual pressure value at the evaporative cooler inlet is less than the target value and the deviation is greater than the preset value, reduce the speed of the dry dust removal fan. If the actual pressure value at the evaporative cooler inlet is greater than the target value and the deviation is greater than the preset value, increase the speed of the dry dust removal fan. If the absolute value of the deviation between the actual pressure value at the evaporative cooler inlet and the target value is less than the preset value, maintain the static speed of the dry dust removal fan set in step S101.

2. The method for improving the heat value of converter dry dust removal gas recovery according to claim 1, characterized in that: After 2 minutes of blowing, the target value of the inlet pressure of the evaporative cooler increased by 50Pa.

3. The method for improving the heat value of converter dry dust removal gas recovery according to claim 1, characterized in that: The preset value is 10Pa.

4. The method for improving the heat value of converter dry dust removal gas recovery according to claim 1, characterized in that: The static speed of the dry dust removal fan is 10-16 gears.

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