Dust collection bag protection device of dry dust collector for blast furnace

Abstract

The utility model discloses a dust collection bag protection device of a dry dust collector for a blast furnace, and belongs to the field of dry dust collection of blast furnaces. The dust collection bag protection device comprises a dry dust collector, a dust conveying pipeline, a raw gas pipeline, a clean gas pipeline and a differential pressure dust coating device, the differential pressure ash coating device comprises an ash conveying pipeline, an isolating valve set, a second ash conveying connector and a blowing assisting fluidization valve. Compared with the prior art, the box body cloth bag and the framework of the dry dust collector are prevented from being replaced in a large scale due to overlarge water content of low-temperature coal gas and poor air permeability.

Description

Technical Field

[0001] The utility model relates to the field of dry dust removal for blast furnaces, in particular to a dust bag protection device for a dry dust collector for blast furnaces. Background Art

[0002] The raw gas produced by the blast furnace contains a large amount of dust. The raw gas first enters the gravity dust collector. Under the action of gravity and inertia, the larger particles of dust are separated from the gas and settled to the bottom of the dust collector cone. The semi-clean gas after preliminary separation enters the dry dust collector. The semi-clean gas pipeline passes through the box and is inserted into the lower part of the box. The clean gas pipeline merges into the clean gas pipeline from the top of the box for external delivery.

[0003] With the increase of smelting intensity, high oxygen enrichment rate and the use of economic raw materials, the top temperature of blast furnaces has been continuously reduced. In particular, the low gas temperature and high moisture content during the blast furnace gas introduction process directly affect the air permeability of dry dust removal bags. The decrease in the air permeability of dust removal bags will lead to excessive dust content in the clean gas after the furnace is opened, unqualified gas quality, delayed TRT commissioning time, and reduced company benefits. In addition, after the high-dust gas enters the hot blast furnace, it will also cause a series of vicious problems such as blockage and slag of the hot blast furnace checker bricks. The furnace opening bags can basically no longer be used and need to be replaced continuously on a large scale, resulting in high spare parts costs.

[0004] The sources of moisture in coal gas during the furnace start-up process are wide. Under low temperature and high pressure, the steam dew point temperature and saturation are low, and a large amount of steam is precipitated as mechanical water. It enters the dry dust collector and comes into direct contact with the bag, causing the bag to absorb water and get stained with dust, making the air permeability worse. The dry dust removal pressure difference is high, and the filtering effect is poor. In severe cases, it can cause deformation of the bag frame and even cracking of the box panel, blockage of the hot air furnace checker bricks, slag formation and other serious accidents.

[0005] However, during the low-temperature coal gas introduction process, blast furnace workers cannot skip this stage, so a simple and effective control method is urgently needed to absorb this part of the mechanical water and prevent the mechanical water from directly contacting the bags, so as to achieve the purpose of protecting the bags. Utility Model Content

[0006] The technical task of the utility model is to provide a dust bag protection device for a dry dust collector for a blast furnace in view of the deficiencies of the above existing technologies, so as to eliminate the influence of mechanical water in the coal gas on the dry dust bag, achieve the goal of causing no damage to the equipment when introducing coal gas at low temperature into the blast furnace, and achieve the purpose of low-cost furnace start-up, rapid production and efficiency.

[0007] The utility model solves the technical problem by a technical solution: a dust bag protection device for a dry dust collector for a blast furnace, comprising a dry dust collector, an ash conveying pipeline, a raw gas pipeline, and a clean gas pipeline; the dry dust collector comprises a box body and a dust bag; the characteristic is that it also comprises a pressure difference ash coating device; the upper part of the box body is connected to the raw gas pipeline through an inlet valve group, connected to the clean gas pipeline through an outlet valve group, and is also provided with a release port with a release valve; the bottom of the box body is connected to the ash conveying pipeline through an ash discharge valve group; the ash conveying pipeline The end of the channel is connected to the nitrogen channel through the first blowing fluidization valve; a first ash delivery interface is provided on the side wall of the ash conveying pipeline between the first blowing fluidization valve and the ash unloading valve group, which is used to connect with the ash delivery device; the pressure difference ash coating device includes an ash conveying pipeline, an isolation valve group, a second ash delivery interface and a blowing fluidization valve; one end of the ash conveying pipeline is connected to the part of the raw gas pipeline before entering the dry dust collector through the isolation valve group, and the other end is connected to the second blowing fluidization valve; the side wall of the ash conveying pipeline has a second ash delivery interface, which is used to connect with the ash delivery device.

[0008] Furthermore, the above-mentioned ash conveying device is a suction pressure conveying vehicle.

[0009] Furthermore, the above-mentioned ash conveying pipeline is a DN150 pipeline.

[0010] Furthermore, the second ash delivery interface is disposed adjacent to the second blowing-assisting fluidization valve.

[0011] Compared with the prior art, the utility model has the following outstanding beneficial effects:

[0012] 1. Avoid large-scale replacement of the bag and frame of the dry dust collector due to excessive water content and poor air permeability of low-temperature gas, which has huge economic benefits;

[0013] 2. The TRT can be put into use 3 days after the blast furnace is put into operation, which is 15 days earlier than the TRT can be put into use after the gas dust content reaches the standard, so as to achieve the purpose of low-cost furnace start-up and rapid production and efficiency;

[0014] 3. Reduce the work intensity and operation risks caused by the replacement of dry dust bag damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments of the specification. In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0017] In the following embodiments, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present utility model application can be understood according to the specific circumstances.

[0018] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", "end", "side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the utility model application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the utility model application.

[0019] like Figure 1 As shown, the utility model is a dust bag protection device for a dry dust collector 1 for a blast furnace, comprising a dry dust collector 1, an ash conveying pipeline 2, a raw gas pipeline 3, a clean gas pipeline 4 and a pressure difference ash coating device.

[0020] The dry dust collector 1 includes a box body and dust removal bags. The upper part of the box body is connected to the raw gas pipeline 3 through the inlet valve group 5, and is connected to the clean gas pipeline 4 through the outlet valve group 6. It is also provided with a release port with a release valve 7. The bottom of the box body is connected to the ash conveying pipeline 2 through the ash discharge valve group 8. The end of the ash conveying pipeline 2 is connected to the nitrogen channel through the first auxiliary blowing fluidization valve 13. A first ash delivery interface 9 is provided on the side wall of the ash conveying pipeline 2 between the first auxiliary blowing fluidization valve 13 and the ash discharge valve group 8 for connecting with the ash delivery device. In this embodiment, the ash delivery device is a suction pressure delivery vehicle.

[0021] The pressure differential ash coating device includes an ash delivery pipeline 10, an isolation valve group 11, a second ash delivery interface 12 and an auxiliary blowing fluidization valve. One end of the ash delivery pipeline 10 is connected to the portion of the raw gas pipeline 3 before entering the dry dust collector 1 through the isolation valve group 11, and the other end is connected to the second auxiliary blowing fluidization valve 14. The side wall of the ash delivery pipeline 10 adjacent to the second auxiliary blowing fluidization valve 14 is provided with a second ash delivery interface 12 for connecting to the ash delivery device. In this embodiment, the ash delivery device is a suction pressure delivery vehicle. The ash delivery pipeline 10 in this embodiment is a DN150 pipeline. The auxiliary blowing fluidization is nitrogen-assisted blowing fluidization.

[0022] The method of using the utility model is as follows:

[0023] (1) Pre-ashing process before furnace opening

[0024] The pre-ashing process before furnace opening is performed before the cold blast furnace is opened.

[0025] The specific method is: close the inlet valve group 5 and the outlet valve group 6, open the ash discharge valve group 8 and the relief valve 7, connect the first ash delivery interface 9 to the suction pressure delivery vehicle, and use the suction pressure delivery vehicle to blow the dust ash from the bottom of the dry dust collector 1 into the interior of the box through the ash delivery pipeline 2, and adhere to the surface of the dust bag to form a pre-sprayed ash film.

[0026] In order to ensure better uniform spraying, the ash conveying pipeline 2 is provided with a first ash delivery interface 9 on the side wall of the ash conveying pipeline 2 between the first auxiliary blowing fluidizing valve 13 and the ash discharge valve group 8. The dust removal ash is fluidized and sprayed from the ash discharge valve group 8 and the first auxiliary blowing fluidizing valve 13 at the lower part of the box body of the dry dust collector 1 through the ash conveying pipeline 2. After fluidization, it is evenly blown into the surface of the filter bag inside the box body, so that the ash adheres to the surface of the dust bag to form a pre-spraying ash film.

[0027] The pre-spraying ash used in this stage has a specific gravity of ≤0.8; humidity ≤3%; particle size less than 80 mesh; temperature 30-50℃. The pre-spraying volume of a single box is controlled at 10-15t. Fluidizing nitrogen pressure 400-600kpa.

[0028] The dust removal ash may be gravity ash, dry dust removal ash, cast house dust removal ash, etc.

[0029] (2) Ash spraying process after blast furnace opening and coal gas introduction

[0030] The ash spraying process after the blast furnace is opened and the coal gas is introduced is used for ash coating in the initial stage of the furnace opening, that is, it is continuously used in the stage from the introduction of coal gas to the raw coal gas temperature reaching about 80°C, and backblowing is performed during use; in the optimization plan, backblowing is performed while maintaining a pressure difference greater than 3kpa.

[0031] The specific method is: open the isolation valve group 11, connect the second ash delivery interface 12 to the suction pressure delivery vehicle, use the suction pressure delivery vehicle to spray the dust ash into the raw gas pipeline 3 through the ash delivery pipeline 10, and use nitrogen to assist fluidization. The injection amount is controlled at 4t / h, so that the fluidized dust ash is brought into the box of the dry dust collector 1 through the coal gas flow generated by the blast furnace, so that the ash adheres to the surface of the dust bag to form an ash film. At this stage, the switch state of the vent valve 7 on the dry dust collector 1 is synchronized with the coal gas introduction process, that is, the box vent is opened before the coal gas is introduced, and the box vent is closed after the coal gas is introduced.

[0032] The filter bags are back-blown and cleaned according to the internal pressure difference of the box to reduce the pressure difference of the box, so as to avoid the problem that the high pressure difference of the box affects the life of the filter bags due to the low temperature of the raw gas, low dust content and high moisture content in the gas, and the moisture adhering to the surface of the dust removal bag to hinder the air permeability of the filter bags.

[0033] In this stage, the pre-spraying material should have a specific gravity of ≤1.5; humidity ≤3%; particle size less than 80 mesh; and temperature of 30-50℃.

[0034] Through the above process, ash is sprayed at low temperature to form an ash film, which prevents the moisture in the coal gas from combining with the surface of the dust bag, avoiding the large-scale replacement of the box bag and frame caused by the deterioration of the air permeability of the dust bag. Through the pre-ash spraying and ash spraying operations of this method, the blast furnace can meet the conditions for TRT to be put into use 3 days after it is put into production, which is 15 days earlier than the use of TRT after the coal gas dust content meets the standard, achieving the purpose of low-cost furnace opening and rapid production and efficiency.

[0035] It should be noted that the specific embodiments of the present invention have been described in detail. For those skilled in the art, various obvious changes to the present invention without departing from the spirit and scope of the present invention are within the protection scope of the present invention.

Claims

1. A dust bag protection device for a dry dust collector for a blast furnace, comprising a dry dust collector, an ash conveying pipeline, a raw gas pipeline, and a clean gas pipeline; the dry dust collector comprises a box body and a dust bag; the characteristics are: Also included is a pressure differential lime coating device; The upper part of the box is connected to the raw gas pipeline through the inlet valve group, connected to the clean gas pipeline through the outlet valve group, and is also provided with a relief port with a relief valve; the bottom of the box is connected to the ash conveying pipeline through the ash unloading valve group; the end of the ash conveying pipeline is connected to the nitrogen channel through the first auxiliary blowing fluidization valve; a first ash delivery interface is provided on the side wall of the ash conveying pipeline between the first auxiliary blowing fluidization valve and the ash unloading valve group, which is used to connect with the ash delivery device; The pressure difference ash coating device includes an ash conveying pipeline, an isolation valve group, a second ash conveying interface and an auxiliary blowing fluidization valve; one end of the ash conveying pipeline is connected to the part of the raw gas pipeline before entering the dry dust collector through the isolation valve group, and the other end is connected to the second auxiliary blowing fluidization valve; the side wall of the ash conveying pipeline is provided with a second ash conveying interface for connecting to the ash conveying device.

2. The dust bag protection device for a dry dust collector for a blast furnace according to claim 1 is characterized in that: The ash conveying device is a suction pressure conveying vehicle.

3. The dust bag protection device for a dry dust collector for a blast furnace according to claim 2 is characterized in that: The ash conveying pipeline is a DN150 pipeline.

4. The dust bag protection device for a dry dust collector for a blast furnace according to claim 2, characterized in that: The second ash delivery interface is disposed adjacent to the second blow-assisting fluidization valve.

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