KR20040025935A - Method for scavenging precoolers of a coking plant - Google Patents

Abstract

The invention relates to a method for scavenging the precoolers of a coking plant. The inventive method is characterized by scavenging the precoolers with the liquid phase produced from the collecting main and using a liquid phase from at least one collecting main that is not impinged upon by the condensation products of the precoolers.

Description

METHOD FOR SCAVENGING PRECOOLERS OF A COKING PLANT}

The tan-brown mixture of gas and steam, namely the coke oven untreated gas, which occurs during the drying of coal, contains a small amount of solid and naphthalin components.

The coke oven untreated gas is first cooled directly from the main collector to the so-called main collector water.

Here the coke oven untreated gas is cooled to a temperature of about 80 ° C., while at the same time a portion of the solid components of the coke oven untreated gas are washed and separated from the liquid material with tar and condensate.

Residual solid components bound to fine tar droplets and water droplets in the form of aerosols reach a so-called precooler with coke oven untreated gas. The coke oven untreated gas is cooled from about 80 ° C. to about 20 ° C. by indirect cooling.

In this cooling process, most of the naphthalin contained in the coke oven untreated gas is sublimed.

At the same time, the tar and solid components of the coke oven untreated gas are separated from the outer wall of the cooling pipe of the precooler.

Also with regard to sublimated naphthalin, the risk of clogging of the precooler may occur after a relatively short operating time.

Solid and naphthalin deposits on the cooling pipes by continuous watering at the top and center of the precooler with liquid materials obtained from the main collector (tar-water-emulsion consisting of about 30% tar and about 70% water). Should be prevented.

Since this tar-water-emulsion is already nearly saturated with naphthalin and also contains solids, this continuous precooler watering does not have a significant effect on increasing the operation of cooling the coke oven gas.

For this reason, it is common to wash the precooler with steam on a daily basis.

Since the precooler is not operated during the cleaning process, a separate cooling means must always be provided.

The condensate and naphthalin-containing washing tar discharged from the precooler cannot be transferred directly for tar separation because it is at a temperature of about 20 ° C., because otherwise, there is no emulsion formation and no further tar separation occurs. Because it does not.

Thus, in general, the precooler condensate is refluxed with each of the untreated gas main collectors of the coke oven battery together with the washing tar containing the naphthalin component, where it is mixed with the hot liquid material generated in the coke oven.

In addition, the refluxed precooler condensate and washing tar are mixed with tar generated in the coke oven, and the temperature rises to about 80 ° C. Thus, only tar, in which naphthalin is concentrated, reaches the tar separator and washing of the precooler is performed.

In order to reach the defined limits for hydrogen sulfide and ammonia content in the coke oven gas cleaned after gas cleaning, the precooler discharge temperature needs to be kept constantly low.

Constant precooling of the coke oven untreated gas must be ensured and clogging of the precooler must be prevented.

DE 100 51 349 A1 is known for obtaining naphthalin from coke furnace untreated gas, in which the coke furnace untreated gas is cooled and naphthalin contained in the coke furnace untreated gas is obtained directly.

In DE 100 07 503 A1 a method of treating coke oven untreated gas is known, in which the coke oven untreated gas is cooled in the main collector via an electronic filter and then passed to the precooler, where the outlet of the electronic filter is cleaned of the precooler. Used for

In DE 34 23 798 C2, it is known that coke oven untreated gas is first cooled through an electronic filter in the main collector and then directed to a precooler.

Although the majority of the solids in the crude gas are separated by coke through the electronic filter, the risk of naphthalin depositing on the cooling pipe of the precooler is not prevented.

This process also requires the process of watering the tar-water-mixture for the separation of deposits.

In DE 26 52 499 A1 a coke oven untreated gas cooling method is known, in which precooling takes place in two stages, in which the precooler is not sprinkled and in the second stage the Watering is done.

In DE 36 14 851 A1 a method for cleaning the precooler of a caulking plant is known, in which the precooler is cleaned with liquid material obtained from the main collector.

Also in this method, it is further proposed that a light component (BTX-aromatic compound) is provided to the coke oven untreated gas so that a sufficient amount of solvent for the sublimed naphthalin can be present in the precooler.

The present invention relates to a precooler cleaning method of a caulking plant according to the introduction of claim 1.

Other details, features, and advantages of the subject matter of the present invention are described by way of the following figures and description, which illustrate by way of example a preferred embodiment of a method for cooling a caulking plant. The drawings are as follows.

1 shows a process diagram of a method for sectioning a precooler with low naphthalinic tar.

SUMMARY OF THE INVENTION An object of the present invention is to stably prevent clogging of a precooler due to naphthalin deposits, thereby ensuring high operability of the precooler, and providing a precooler cleaning method for a caulking plant, in which no additional cleaning process is required. will be.

This object is achieved through the features of claim 1.

Other modifications are made in accordance with the features of the dependent claims.

The key of the process according to the invention is the use of liquid material which occurs upon cooling of the raw gas directly in the raw gas main collector and which contains a relatively small amount of naphthalin for the cleaning of the precooler.

The tests revealed that the tar, separated by a direct cooling in the main collector to a temperature of about 80 ° C., contained only a small amount (about 2%) of naphthalin.

To date, the results have been surprising because it has been thought that most of the naphthalin contained in the coke oven untreated gas will be discharged with tar due to the excellent solubility of naphthalin in tar.

In fact, the concentration of tar in the main collector is achieved by refluxing the precooler condensate described above with naphthalin.

Therefore, in the present invention, the liquid material of the at least one untreated gas main collector is not mixed with the precooler condensate including the washing tar, which has already been concentrated with naphthalin, and is collected in a separate tar separator.

These separately collected liquid substances include low naphthalinic tars. As a separate tar separator, a conventional tar separator can be used.

The advantage is that no additional tar separator and no additional investment is required.

In the present invention, such a low naphthalinic liquid substance is used for cleaning the cooling pipe in the precooler.

In another variant, the water component of the separately collected liquid substance is separated in a separate tar separator.

Low naphthalinic tar may be mixed with water for use as a cleaning tar.

In other variations, tar or liquid material may also be separated from the solids in the tar centrifuge.

In this way, tars or liquids are safely blocked from reaching the precooler.

As already shown, in the process of cooling from about 80 ° C. to about 20 ° C., naphthalin of untreated gas with coke is sublimed and deposited on the cooling pipe of the precooler.

It is possible to prevent clogging of the precooler by washing the liquid material continuously obtained in advance in the at least one untreated gas main collector which has not collided with the condensate of the precooler with low naphthalinic tar.

In principle, the cleaning process through the low naphthalinic tar can be carried out via any nozzle suitable for this, preferably at the top of the precooler.

Since this tar is low naphthalinic, the cleaning effect of the tar can be successfully achieved at only one location of the precooler.

In another variant of the invention the washing takes place in three places: top, center and bottom.

This safely inhibits deposition on the cooling pipes.

Preferably the washing in the precooler is through a well known hollow nozzle (DE-PS 197 48 693).

This hollow nozzle distributes low naphthalinic tar evenly on the inner wall and pipe of the precooler.

The tar and water soluble condensate, typically discharged from the legs of the precooler, is sent to the remaining raw gas main collector, where it is treated together with the liquid material resulting from the direct cooling of the raw gas.

The process according to the invention allows for continuous precooler operation, since no deposits are formed in the cooling pipes and no further cleaning process is required.

In addition, emissions from further cleaning processes (steam cleaning) are suppressed. Washing with low naphthalinic tars significantly increases the precoolability.

The cost of investment is reduced because fewer precoolers are required. In addition, since the cleaning process can be reduced, labor and material costs are saved.

Continuous precooler operation ensures the maintenance of untreated gas temperatures with constant low coke at the precooler outlet.

In addition, since the cleaning of hydrogen sulfide, ammonia and benzol can be effectively performed at a constant low temperature, the quality of the coke oven gas is improved. Since hydrogen sulfide and ammonia-containing condensate are suppressed, no corrosion occurs when acquiring benzol.

The process steps applied according to the invention described above and in the claims and examples are not subject to any special exceptions with respect to the process conditions, so that selection criteria known in the field of application fall within the scope of the claims. It can be applied unlimitedly.

1 schematically shows a method of treating coke oven untreated gas. The coke oven untreated gas generated in the coke oven 1 is cooled to about 80 ° C. through the water 14 for direct spraying in the main collectors 2 and 2a and is delivered to the precooler 3.

Before reaching the consumer 5, the coke oven untreated gas is transferred from the precooler 3 to the coke oven gas scrubber 4.

Condensate formed in the precooler 3, including the highly naphthalinic washing tar, is transferred to the main collector 2 via a pipe 13, and heated and mixed through the tar formed in direct raw gas cooling. .

The liquid material of the main collector 2 is transferred to the tar separator 6 via a pipe 9 to separate the tar from the coal water mixture in the cooling water.

The coal-water mixture is conveyed through pipe 7 for another treatment process. The separated hypernaphthalinic tar is transported through pipe 8 for loading.

The liquid material of the main collector 2a is transferred to a separate tar separator 11 through a pipe 10 and separated into a coal-water mixture and a low naphthalinic tar.

The low naphthalinic tar is conveyed to the precooler 3 via a pipe 12, where it is used for cooling the cooling pipe.

<Description of main parts of drawing>

1: coke oven

2: collecting main

2a: main collector

3: precooler

4: coke oven gas scrubber

5: consumer

6: tar separator

7: pipe (coal-water mixture)

8 pipe (tar)

9: pipe (liquid material containing high naphthalinic tar)

10: pipe (liquid material containing low naphthalinic tar)

11: separate tar separator

12 pipe (low naphthalinic washing tar)

13: pipe (precooler condensate containing high naphthalene tar)

14: water for spraying

Claims (6)

In the precooler cleaning method of the caulking plant in which the precooler is washed with the liquid material obtained from the main collector, Wherein at least one liquid phase material of the main collector is used that does not impinge on the precooler condensate. The method of claim 1, wherein the liquid material of the at least one main collector not filled with the precooler condensate is transferred to a separate tar separator, wherein the low naphthalinic tar obtained in the tar separator is used for washing the precooler. Characterized in that the method. The method according to claim 1 or 2, wherein the low naphthalinic tar or liquid material obtained in the separate tar separator is transferred to a tar centrifuge for separation of solids, and then used for washing in the precooler. Characterized in that the method. The method according to any one of claims 1 to 3, wherein the washing in the precooler is through a hollow nozzle. The method according to any one of claims 1 to 4, wherein the washing process in the precooler takes place at only one processing position. The method according to any one of claims 1 to 5, wherein the washing in the precooler takes place at the top, the center and the bottom.