阅读说明：本技术 一种高炉热风炉余热回收区域烟气管道在线切割工艺 (Online cutting process for flue gas pipeline in waste heat recovery area of blast furnace hot blast stove ) 是由 杨国新 柏徳春 邹林 何勇 周凌云 刘引锋 陈小东 于 2019-04-20 设计创作，主要内容包括：本发明涉及一种高炉热风炉余热回收区域烟气管道在线切割工艺,其工艺步骤是：第一步,使空气、煤气预热器退出热风炉余热回收系统；第二步,扭开两个位于烟气预热器内的温度计作为烟气预热器的吸气口,对烟气预热器内部吸入空气的状况进行确认；第三步,将两个烟气预热器出口阀手动打开,通入氮气,对内部气体进行驱赶,混合气体在烟囱的抽力的作用下,全部抽离烟气预热器；第四步,停止通入氮气,在烟囱的抽力的作用下,空气从人孔进入烟气预热器,即可安全切割。在高炉休风前即可完成余热回收区域烟气管道的切割,大幅度缩短高炉配合预热器改造的休风时间,降低对高炉生产影响。(The invention relates to an online cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove, which comprises the following process steps: step one, enabling an air preheater and a gas preheater to exit a hot blast stove waste heat recovery system; turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater; thirdly, manually opening outlet valves of the two flue gas preheater, introducing nitrogen, driving internal gas, and completely pumping the mixed gas out of the flue gas preheater under the action of the suction force of a chimney; and fourthly, stopping introducing nitrogen, and enabling air to enter the flue gas preheater from the manhole under the action of suction force of the chimney, so that safe cutting can be realized. The cutting of the flue gas pipeline in the waste heat recovery area can be completed before the blast furnace is shut down, the shut down time of the transformation of the blast furnace matched with the preheater is greatly shortened, and the influence on the production of the blast furnace is reduced.)

1. An on-line cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove is characterized by comprising the following process steps:

firstly, opening a bypass valve of flue gas, air and coal gas of a hot blast stove, then closing a butterfly valve of an inlet and an outlet of the flue gas, the air and the coal gas, manually confirming the closing on site, and enabling an air preheater and a coal gas preheater to exit a waste heat recovery system of the hot blast stove;

turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater;

manually opening outlet valves of the two flue gas preheaters by 10-20%, simultaneously opening all manholes in the flue gas preheaters, binding the gas alarm on a rod, extending into the flue gas preheaters for confirmation again, extending a nitrogen rubber pipe into the flue gas preheaters from the manholes, introducing nitrogen, driving internal gas, and completely pumping the mixed gas away from the flue gas preheaters under the action of the suction force of a chimney;

and fourthly, stopping introducing nitrogen after 20-30 minutes, and allowing air to enter the flue gas preheater from the manhole to replace the original residual mixed gas under the action of the suction force of the chimney, wherein the flue gas pipeline has the condition of safe cutting in advance after 10-20 minutes.

2. The blast furnace hot blast stove waste heat recovery area flue gas pipeline on-line cutting process according to claim 1, characterized in that: in the second step, if atmospheric air is pumped inwards, the interior of the flue gas preheater can be determined to be in a negative pressure state; the gas concentration is displayed as 0 PPm, and the fact that no gas leaks or residual gas exists in the smoke preheater can be determined.

3. The blast furnace hot blast stove waste heat recovery area flue gas pipeline on-line cutting process according to claim 1, characterized in that: because of carrying out flue gas pipeline on-line cutting operation under the normal production condition of hot-blast furnace, the prerequisite of implementation: detecting the content of CO in the flue gas of the hot blast stove to be qualified; the inlet butterfly valve of the flue gas preheater is closed and then the sealing condition is good; introducing nitrogen to the tail end of the flue header pipe before cutting to dilute and protect the flue gas; during the process of starting the hot blast stove, the air-fuel ratio is regulated to prevent a large amount of unburned gas from entering a flue main pipe.

Technical Field

The invention belongs to the technical field of treatment processes of blast furnace hot blast stove equipment, and relates to an online cutting process of a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove.

Background

In the transformation process of the waste heat recovery area preheater of the blast furnace hot blast stove, if the flue gas blind plate valve on the inner side of the electric butterfly valve of the flue fails, the flue pipe on the inner side of the electric butterfly valve needs to be cut and welded with a blind plate, and the blind plate is thoroughly separated from the flue gas system of the original hot blast stove. The heat insulation of the inner wall of the flue pipeline adopts the prior construction technology of anchoring parts and spraying coating layers: after the blast furnace damping down hot blast stove stops burning (blowing), the flue pipeline is cut and a blind plate is welded. The process is slow in field construction, and the recovery of production of the blast furnace on time is often severely restricted.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the online cutting process for the flue gas pipeline in the waste heat recovery area of the blast furnace hot blast stove, the cutting of the flue gas pipeline in the waste heat recovery area can be completed before the blast furnace stops blowing down, the blowing down time of the blast furnace in cooperation with the transformation of a preheater is greatly shortened, and the influence on the production of the blast furnace is reduced.

The technical scheme adopted by the invention for solving the technical problems is as follows: an on-line cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove comprises the following process steps:

firstly, opening a bypass valve of flue gas, air and coal gas of a hot blast stove, then closing a butterfly valve of an inlet and an outlet of the flue gas, the air and the coal gas, manually confirming the closing on site, and enabling an air preheater and a coal gas preheater to exit a waste heat recovery system of the hot blast stove;

turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater;

manually opening outlet valves of the two flue gas preheaters by 10-20%, simultaneously opening all manholes in the flue gas preheaters, binding the gas alarm on a rod, extending into the flue gas preheaters for confirmation again, extending a nitrogen rubber pipe into the flue gas preheaters from the manholes, introducing nitrogen, driving internal gas, and completely pumping the mixed gas away from the flue gas preheaters under the action of the suction force of a chimney;

and fourthly, stopping introducing nitrogen after 20-30 minutes, and allowing air to enter the flue gas preheater from the manhole to replace the original residual mixed gas under the action of the suction force of the chimney, wherein the flue gas pipeline has the condition of safe cutting in advance after 10-20 minutes.

In the second step, if atmospheric air is pumped inwards, the interior of the flue gas preheater can be determined to be in a negative pressure state; the gas concentration is displayed as 0 PPm, and the fact that no gas leaks or residual gas exists in the smoke preheater can be determined.

Because of carrying out flue gas pipeline on-line cutting operation under the normal production condition of hot-blast furnace, the prerequisite of this technique implementation: detecting the content of CO in the flue gas of the hot blast stove to be qualified; the inlet butterfly valve of the flue gas preheater has good sealing condition after being closed.

Introducing nitrogen to the tail end of the flue header pipe before cutting to dilute and protect the flue gas; during the process of starting the hot blast stove, the air-fuel ratio is regulated to prevent a large amount of unburned gas from entering a flue main pipe.

The invention has the positive effects that:

under the normal production condition of the hot blast stove, the cutting of the flue pipeline is completed in advance, the damping down time of the transformation of the blast furnace matched with the preheater is greatly shortened, and the influence on the production of the blast furnace is reduced. The method is safe and controllable, can be popularized to the modification process of large, medium and small blast furnaces in hot blast stove preheaters in the same industry, and the flue gas blind plate valve is invalid, so that the flue pipe needs to be cut.

Drawings

FIG. 1 is a schematic view of example 1.

In the figure: 1-first flue gas inlet valve, 2-second flue gas inlet valve, 3-gas outlet valve, 4-thermometer, 5-gas bypass valve, 6-inspection manhole, 7-gas outlet valve, 8-first flue gas outlet valve, 9-second flue gas outlet valve, 10-combustion air inlet valve, 11-air bypass valve, 12-combustion air outlet valve, 13-flue gas bypass valve, 14-first flue gas preheater, 15-second flue gas preheater, 16-chimney, 17-gas preheater, 18-air preheater and 19-hot blast stove.

Detailed Description

The present invention will be further described with reference to the following examples.