CN111961775A

CN111961775A - Method for reducing dust deposition of dry-process raw gas main pipeline

Info

Publication number: CN111961775A
Application number: CN202010913437.XA
Authority: CN
Inventors: 冀岗; 张军; 路振毅; 代新文
Original assignee: Shanxi Taigang Stainless Steel Co Ltd
Current assignee: Shanxi Taigang Stainless Steel Co Ltd
Priority date: 2020-09-03
Filing date: 2020-09-03
Publication date: 2020-11-20

Abstract

The invention relates to the field of dry-method coal gas dust removal of a blast furnace. Determining the maximum value Q1 and the minimum value Q2 of the flow range of a box body crude gas branch pipe according to the change of the ash accumulation amount of a crude gas main pipe during the overhaul of a blast furnace, taking the flow average value Q3= (Q1 + Q2)/2 of the box body crude gas branch pipe, obtaining the maximum flow Q4 of the crude gas main pipe according to the experience, and taking the Q4/Q2 for integer according to the total n1 of a dry-method box body, wherein if the remainder of Q4/Q2 is 0, n1= [ Q4/Q2], otherwise n1= [ Q4/Q2] + 1; determining the number n2= Q5/Q3 of used dry box bodies according to the actual flow Q5 of the raw gas main pipeline, wherein the n2 is rounded by adopting a rounding method; and step three, opening the second valve and the corresponding third valve according to the number n2 of the dry box bodies.

Description

Method for reducing dust deposition of dry-process raw gas main pipeline

Technical Field

The invention relates to the field of dry-method coal gas dust removal of a blast furnace.

Background

Blast furnace gas is one of the by-products of blast furnace production. Blast furnace production generates a large amount of blast furnace gas every day (calculated by a medium-sized blast furnace with the daily capacity of 4500t, the daily gas amount is about 618 ten thousand meters), and because the blast furnace gas moves from bottom to top in the blast furnace and the blast furnace burden moves from top to bottom, the blast furnace gas inevitably carries dust, and in order to enable the blast furnace gas to reach the use standard, the blast furnace gas needs to be subjected to a dust removal process. The dry dedusting is the most advanced process for dedusting of modern blast furnaces.

In the daily production of blast furnaces, blast furnace gas with dust is first filtered through a gravity dust collector (a coarse dust collecting device such as a cyclone), and then filtered through a dry dust collecting system. The dry dedusting system can be divided into three parts from the large structure: a crude gas main pipeline, a dry method box body and a clean gas main pipeline. Before the gas enters the dry method box body, the gas firstly passes through a crude gas main pipeline, then passes through a box body crude gas branch pipe, enters the dry method box body, enters a clean gas branch pipe after being filtered by a dust removing cloth bag in the dry method box body, then enters the clean gas main pipeline, and finally qualified gas is produced.

However, in production practice, the ash deposition in the raw gas branch pipes of the box body gradually increases along with the time, and even the ash deposition blocks the inlet pipes of some dust removal box bodies when the pipe ash deposition is serious, so that part of the box bodies (a dry dust removal system generally comprises a plurality of box bodies, for example, a tai-steel 3# blast furnace comprises 12 box bodies) have to be withdrawn, and the work of the box bodies is stopped. In addition, when the crude gas main pipeline is overhauled and cleaned, a large amount of accumulated dust in the pipeline can be found. In a word, the normal production of the blast furnace is seriously influenced by the dust deposition of the box body raw gas branch pipe.

The common hazards are as follows:

1. in daily production, the box body is often blocked by accumulated dust in the pipeline and is forced to be withdrawn. This can seriously affect the ability of the blast furnace to handle gas and even lead to a reduction in blast furnace capacity due to a reduction in the ability to dry process gas.

2. The pressure of the box body crude gas branch pipe supporting structure can be increased due to serious dust deposition of the pipeline, and the phenomenon that the box body crude gas branch pipe collapses can occur in serious cases.

3. When the ash accumulation of the pipeline is serious, the difficulty and the workload of overhauling and cleaning the ash can be increased, the labor cost is increased, and the overhauling time is prolonged.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: how to optimize the use method of the dry method box body, reasonably control the use number of the dry method box body and reasonably use the box bodies at different positions, and achieve the purposes of reducing the ash accumulation of the raw gas branch pipe of the box body, ensuring the normal gas treatment capacity of the blast furnace and the normal production of the blast furnace, and reducing the overhaul difficulty and the workload.

The technical scheme adopted by the invention is as follows: a method for reducing dust deposition of a dry-process raw gas main pipeline comprises the steps that blast furnace gas with furnace dust is filtered by a gravity dust collector, then enters a clean gas main pipeline (5) after passing through a raw gas main pipeline (1), a plurality of box raw gas branch pipes (2), dry-process boxes (3) with the same number as the box raw gas branch pipes (2) and clean gas branch pipes (4) with the same number as the box raw gas branch pipes (2), a first valve (61) and a flowmeter (7) are installed on the raw gas main pipeline (1), a second valve (62) is installed on each box raw gas branch pipe (2), and a third valve (63) is installed on each clean gas branch pipe (4); the method for reducing the ash deposition of the dry-process raw gas main pipeline comprises the following steps

Determining the maximum value Q1 and the minimum value Q2 of the flow range of a box raw gas branch pipe (2) according to the change of ash accumulation amount of a raw gas main pipe during the overhaul of a blast furnace, taking the flow average value Q3= (Q1 + Q2)/2 of the box raw gas branch pipe (2), obtaining the maximum flow Q4 of the raw gas main pipe (1) according to experience, obtaining the total amount n1 of a dry-method box (3), rounding Q4/Q2, if the remainder of Q4/Q2 is 0, n1= [ Q4/Q2], and otherwise n1= [ Q4/Q2] + 1;

determining the number n2= Q5/Q3 of the used dry box bodies (3) according to the actual flow Q5 of the raw gas main pipeline (1), wherein the n2 is rounded by adopting a rounding method;

and step three, opening the second valve (62) and the corresponding third valve (63) according to the number n2 of the dry-method box bodies (3).

In the third step, a second valve (62) and a third valve (63) corresponding to the dry method box body (3) connected with the tail end of the crude gas main pipeline are preferably selected and opened.

The invention has the beneficial effects that: the phenomenon of dust accumulation of the raw gas branch pipe of the box body can be reduced, the smoothness of a dry method system pipeline is ensured, and the normal processing capacity of the blast furnace gas is also ensured. The phenomenon that the raw gas branch pipe of the box body is blocked due to the fact that the tail end box body is not used for a long time is avoided, and working effectiveness of all the box bodies is guaranteed. The labor capacity of workers and the maintenance cost during maintenance are reduced. The pressure to the box raw gas branch pipe supporting structure when the pipe deposition is serious is reduced, and the risk of collapse of the box raw gas branch pipe caused by deposition is eliminated.

Drawings

FIG. 1 is a schematic structural view of the present invention;

the system comprises a raw gas main pipeline 1, a box raw gas branch pipe 2, a dry method box 3, a clean gas branch pipe 4, a clean gas main pipeline 5, a clean gas main pipeline 61, a first valve 62, a second valve 63, a third valve 7 and a flowmeter.

The specific embodiments,

Blast furnace raw gas belongs to dust-containing gas, and when the dust-containing gas flows at different speeds in a pipeline, different dust drops can be generated. When the diameter of dust particles in coal gas is fixed, the larger the coal gas flow velocity is, the less obvious the dust drop phenomenon is, and conversely, the smaller the coal gas flow velocity is, the larger the dust drop is. When the gas flow rate is constant, the dust drop is more obvious when the diameter of dust particles in the gas is larger. Therefore, the quantity and the using mode of the dry method box bodies are reasonably controlled under the conditions of different coal gas quantities according to the actual production conditions, so that the flow speed of the coal gas is controlled, and the purposes of minimizing the dust drop in the raw gas branch pipe pipeline of the box body and not blocking the raw gas branch pipe of the box body are achieved.

Taking a Tai steel 3# blast furnace as an example, the reasonable average flow velocity range of the branch pipes of the crude gas pipeline is determined to be 14.5-18.1 m/s according to the change of the ash accumulation amount of the crude gas pipeline in the previous overhaul of the blast furnace. The number of the dry dedusting design boxes is 12.

Under the normal production condition, the number that the dry process box used is adjusted according to the change of the actual gas volume of blast furnace (the actual flow Q5 of crude gas female pipe) to satisfy the requirement of box crude gas branch pipe pipeline to the gas velocity of flow, the calculation process is: number used for dry box n2= actual flow rate of raw gas mother pipe Q5 (m/s)/16.3, wherein 16.3: the average flow velocity of the branch pipes of the crude gas pipeline in the box body is (16.3 = (14.5 + 18.1)/2).

The flow rate of the raw gas branch pipes and the number of the used boxes are as follows.

If all the boxes are not needed to be used through calculation, a plurality of boxes at the tail end of the raw gas pipeline of the boxes are preferentially used, and the other boxes are used alternately, so that the dust accumulation at the far end of the raw gas main pipe and the dust accumulation of other box inlet pipelines are avoided.

Under special production conditions, if the gas quantity is greatly reduced, the principle is also followed.

Claims

1. The utility model provides a method for reducing female pipeline deposition of dry process raw coke oven gas, the blast furnace gas that has the furnace dust is filtered through gravity dust collector after through the female pipeline of raw coke oven gas (1), many box raw coke oven gas branch pipes (2), with dry process box (3) of box raw coke oven gas branch pipe (2) the same quantity, with box raw coke oven gas branch pipe (2) the same quantity clean coal gas branch pipe (4) back income clean coal gas female pipeline (5), its characterized in that: a first valve (61) and a flowmeter (7) are installed on the raw gas main pipeline (1), a second valve (62) is installed on each box body raw gas branch pipe (2), and a third valve (63) is installed on each clean gas branch pipe (4); the method for reducing the ash deposition of the dry-process raw gas main pipeline comprises the following steps

2. The method for reducing ash deposition in the dry raw gas main pipeline according to claim 1, wherein the method comprises the following steps: in the third step, a second valve (62) and a third valve (63) corresponding to the dry method box body (3) connected with the tail end of the crude gas main pipeline are preferably selected and opened.