KR101053353B1 - COB cooling condensing apparatus and method - Google Patents

Abstract

An apparatus and method for cooling and condensing coke oven gas while installing condensers in parallel and automatically cleaning impurities adhering to the inner surface of the condenser continuously without interruption of operation. Two condensers 4A, 4B connected in parallel; Steam valves (9) and (9 ') located at the top of the outside of the condenser to supply cleaning steam to the condenser; Drain valves 14, 14 'mounted at the outer bottom of the condenser to discharge the wash water; located at the front of the condenser front shutoff valves 10, 12, and the temperature of the coke oven gas entering the condenser / Shear temperature / pressure sensor 7 for measuring pressure; A rear end temperature / pressure sensor (8) positioned at the rear end of the condenser rear end valves (11) and (13) for measuring the temperature and / or pressure of the coke oven gas discharged from the condenser; Condenser front end shutoff valves 10 and 12 positioned at the front end of each condenser 4A and 4B to regulate the inflow of coke oven gas into the condenser; And a condenser rear shut-off valve (11) and (13) positioned at the rear end of each condenser (4A) and (4B) to control the discharge of the COG from the condenser. In addition, (a) the water in the COG while passing through the gas blower (1), the after cooler (2) and the water separator (3) through one condenser (4A, or (4B)) of the condenser connected in parallel. The condensation is removed; (b) Measuring the temperature / pressure of the COG entering the condenser and the COG exiting the condenser at the pressure and temperature sensors 7 and 8 at the front and rear ends of the two condensers 4A and 4B connected in parallel. step; (c) If the pressure drop measured by the front end temperature / pressure sensor 7 and the rear end temperature / pressure sensor 8 exceeds 150 mmH ₂ O or the temperature difference is less than 20 ° C, the front end of the operating condenser and Opening and closing the front and rear valves of the condenser, which are waiting for the downstream valve to be closed and the cooling condensation process of the COG to be continued; (d) The washing valve at the upper part of the condenser, in which the front and rear valves are closed, is opened, and steam is injected into the high pressure steam from the steam nozzle (15 or 15 ') mounted on the upper part of the condenser. Washing the attachment; (e) discharging the washed deposit through the discharge line; And (f) step (b)-until the pressure drop measured at the front temperature / pressure sensor 7 and the rear temperature / pressure sensor 8 is 150 mmH ₂ O or less or the temperature difference is measured to be 20 ° C. or more. A method of cooling condensation of coke oven gas is provided comprising repeating (e) to wash the internal deposits of the condenser. With the above apparatus and method, the condenser of the COG cooling condenser can be automatically cleaned to effectively clean the condenser within a short time without shutting down the apparatus.

COG refrigerated condensers, condensers, flat nozzles

Description

COG Condensing Apparatus and Method             

1 is a view showing a COG cooling condensation apparatus used in the method of the present invention,

2 is a view showing the internal structure of the condenser and the connection structure to the outside of the COG cooling condensation apparatus.

Brief description of the main parts of the drawing

1 ... gas blower 2 ... aftercooler

3 ... Water Separator 4 ... Cooling Condenser (Gas / Water Exchanger)

5 ... water condenser (cooling water chiller) 6 ... refrigerant pump

7 ... Condenser front pressure or temperature sensor 8 ... Condenser back pressure or temperature sensor

9, 9 '... Steam valve 10 ... Condenser a shear shutoff valve

11 ... condenser a rear shutoff valve 12 ... condenser b front shutoff valve

13 ... Condenser b rear shutoff valve 14, 14 '... drain valve

15, 15 '... Steam nozzle 16 ... Controller

The present invention is a coke oven gas (COG) produced as a by-product in the coke coagulation process of steel mills

It relates to a cooling condensation apparatus and method of.

More specifically, the present invention provides a condenser in parallel to continuously operate without interruption

An apparatus and method for cooling and condensing coke oven gas while automatically cleaning impurities adhering to an inner surface of a condenser.

Among the by-product gases generated in the steelmaking process, COG is used to dry coal in the coke manufacturing process.

It is a combustible mixed gas that is composed mainly of hydrogen, methane and carbon monoxide.

This is shown in Table 1.

[Table 1] COG Composition and Properties

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Other small amount of water-soluble impurities such as hydrogen sulfide (H ₂ S), hydrogen cyanide (HCN), ammonia (NH ₃ ) and organic substances such as benzene, toluene, xylene, tar, naphthalene are included, as shown in Table 2. .

[Table 2] COG Main Impurity Content in Steel Mill (g / Nm ³ )

[Table 3] Effect of Impurity Deposit in COG Pipe

The COG is an important heat source that is used entirely in fuel gas, such as a heating furnace, in a steel mill. However, in use, various impurities in the COG are deposited in the pipe, causing problems as shown in Table 3 below.

In order to solve these problems related to the use of COG, steelworks have been examined to eliminate the causes of COG piping closure, and some of them have been applied in actual field. In practice, a method of suppressing the deposition by applying a chemical of feramine is applied, but it is not currently applied due to the deposition of sediment inside the pipe during long-term operation, and the filter is used for the front end of the condenser, but once every two days Maintenance or replacement is required.

In particular, the main causes of impurity deposition in COG pipes are hydrogen sulfide in COG, and HCN, NH ₃ , naphthalene, tar, etc., which are found to promote deposition and corrosion by moisture present above saturation. Sedimentation and corrosion actions are as shown in Table 4 below.

[Table 4] Generation Sources of COG Pipeline Sediments and Their Effects

By-product COG was flushed with ammonia water to remove the impurities in the steelmaking process.

After cooling, the first cooler passes through a blower through an electrostatic precipitator, and the elevated temperature is dropped to about 30 ° C. from the final cooler. After that, the ammonia is absorbed through the ammonia absorption tower, and BTX, tar, naphthalene, etc. are absorbed and removed from the benzol scrubber.

Absorption liquid used in the ammonia absorption tower is the ordination from the decanter and the absorption through the absorption tower.

A sap is a mixed solution of desalinated water and soft water reprocessed in steel. Absorption liquid from the absorption tower is removed from the ammonia and some of the hydrogen sulfide and hydrogen cyanide adsorbed in the steel and flows into the waste water treatment plant. Inflow, ammonia is decomposed into hydrogen and nitrogen, and then burned together with other gases and released into the air as nitrogen, water vapor, SOx, and NOx.

As shown in Table 2, hydrogen sulfide, ammonia,

There is a small amount of impurities in the lamp and caustic soda in cold rolling mills to remove it.

Impurities are removed using an absorbent liquid containing the solution as the main component.

The deoiling plant operating in the cold rolling mill is a modified Fumaks Process, which is called Sumimoto Metals.

Industries Ltd. Picric acid, developed as an absorbent and acts as an oxygen carrier

A mixture of picric acid and NaOH that acts as an alkali source is used. The process

Due to the excellent process efficiency, hydrogen sulfide is removed with an efficiency of more than 95%, and ammonia is also removed to reduce the concentration of hydrogen sulfide and ammonia to 10 ppm or less in normal operation.

However, in the gas generated after the deoiling process absorbing hydrogen sulfide and HCN,

It contains water, which is the main cause of corrosion and pipe deposition.

The problem of pipe deposition at the rear end of deoiling equipment in COG cold rolling mill is                         

Caused by pollination. Therefore, the COG moisture removal device using the cooling condensation method is currently installed and operated to remove the water, and as a result, it has a significant effect on reducing pipe deposits and preventing corrosion.

However, when the water removal apparatus is operated for a long time, impurities in the COG removed together with water are deposited on the inner surface of the condenser, not only to reduce the cooling efficiency of the gas, but also to stop the operation of the facility due to the gas pressure drop. The interior should be cleaned.

As a result, the operation of the furnace using COG as fuel is disturbed, and the condenser is dismantled,

A lot of manpower and time is spent on cleaning and assembly.

Accordingly, an object of the present invention can facilitate the maintenance and operation of the COG purification apparatus.

To provide an effective COG purification apparatus and method.

Another object of the present invention is to provide an apparatus and method for purifying coke oven gas while automatically cleaning impurities adhering to the inner surface of a condenser continuously without operation interruption.

According to one aspect of the invention,

Two condensers 4A, 4B connected in parallel,

Steam valves 9, 9 'located at the outer top of the condenser to supply a cleaning steam to the condenser;

Steam nozzles 15 and 15 'mounted on the upper end of the condenser for injecting high pressure steam into the condenser; And

Drain valves 14, 14 'mounted at the outer bottom of the condenser for discharging the washings;

A shear pressure or temperature sensor 7 positioned at the front end of the condenser shear shutoff valves 10 and 12 and measuring the pressure or temperature of the coke oven gas flowing into the condenser;

A rear end pressure or temperature sensor 8 positioned at a rear end of the condenser rear end shutoff valves 11 and 13 for measuring the pressure or temperature of the coke oven gas discharged from the condenser;

Condenser front end shutoff valves 10 and 12 positioned at the front of each condenser 4A and 4B to regulate the inflow of coke oven gas into the condenser; And

 A cooling condensation apparatus for the coke oven gas is provided that includes a condenser rear shutoff valve (11) and (13) located at the rear end of each condenser (4A) and (4B) to regulate the discharge of the coke oven gas from the condenser.

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According to another aspect of the present invention,

(a) Coke oven gas passing through a gas blower (1), after cooler (2) and a water separator (3) through a condenser (4A or 4B) of one of the condensers connected in parallel. Condensation of moisture in the water;

(b) the temperature of the coke oven gas entering the condenser and the coke oven gas exiting the condenser at the pressure or temperature sensors 7 and 8 at the front and rear ends of the two condensers 4A and 4B connected in parallel, or Measuring pressure;

(C) If the pressure drop measured by the front pressure or temperature sensor 7 and the rear pressure or temperature sensor 8 is 150 mmH ₂ O or more, or the temperature difference is measured to be 20 ° C. or less, the front end of the operating condenser and The valves at the rear stage are closed and the valves at the front and rear stages of the condenser in the air are opened so that the cooling condensation process of the coke oven gas can be continued;

(d) The steam cleaning valve on the upper part of the condenser, in which the front and rear valves are closed, is opened, and steam is injected into the high pressure steam from the steam nozzle (15 or 15 ') mounted on the upper part of the condenser. Washing the attachment;

(e) discharging the washed deposit through the discharge line; And
(f) steps (b) to (b) until the pressure drop measured by the front pressure or temperature sensor 7 and the rear pressure or temperature sensor 8 is less than 150 mmH ₂ O or the temperature difference is greater than 20 ° C. A method of cooling condensation of coke oven gas is provided comprising repeating e) to wash internal deposits of the condenser.

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The overall system of the COG purification apparatus according to the present invention is general. However, in the present invention, two condensers 4A and 4B used in the conventional COG gas cooling condensation process system are arranged in parallel, and a steam nozzle for cleaning the condenser is installed inside each condenser.

At this time, the front or rear pipes of the front shutoff valves 10, 12 and the rear shutoff valves 11, 13 of the cooling condenser, respectively, a pressure or temperature sensor 7 for detecting a cleaning time of the condenser. And (8) are mounted. The signal of the value measured at the pressure or the temperature sensors 7, 8 is transmitted to the controller 16. If it is determined that the values measured at the front and rear pressure or temperature sensors need to be cleaned in comparison with the preset values to determine the time of cleaning the condenser, the controller 16 may determine the condenser 4A or ( Control the shielding of the front and rear valves 10 and 11 or 12 and 13 of 4B).

At the same time, the valve to the condenser, which is not used for cooling condensation of the COG, is opened, and the flow path of the COG gas is changed.

After the valves before and after the condenser are shielded, the steam valve 9 or 9 'for introducing steam to the condenser to be cleaned by the controller 16 is opened. The opening and closing of the steam valve 9 or 9 'is controlled by the controller 16 in accordance with the pressure or temperature sensed by the pressure or temperature sensors 7, 8.

When the pressure drop exceeding the set pressure or a temperature difference smaller than the set temperature difference is sensed at the rear pressure or the temperature sensor 8, the condenser washing is started by attaching a large amount of deposit inside the condenser.

When the pressure of the rear pressure sensor 8 drops more than 150 mmH ₂ O compared to the pressure sensor 7 of the front end, the condenser washing is controlled to start. Even when there is no impurity inside the condenser during operation of the device, the pressure drop of about 50 mm H ₂ O is caused by the condenser device itself. Since the flow rate of the gas decreases when the pressure drops, it is determined that the foreign matter inside the condenser should be cleaned when the pressure drop at the rear end of the condenser is greater than 150 mmH ₂ 0, considering the flow fluctuation that allows the burner to operate normally.

In addition, it is determined that the condenser should be cleaned when the temperature difference detected by the temperature sensor at the front and rear ends of the condenser is less than 20 ° C. The reason is that, considering the design capacity of the condenser, it is determined that the temperature difference of 20 ° C. or less is due to insufficient cooling effect due to internal deposits.

When it is determined that the condenser should be cleaned by the pressure or temperature measurement, the valves before and after the condenser operated by the controller 16 are blocked to prevent the inflow of COG gas into the condenser and to block the inflow of COG gas. The steam valve 9 or 9 'at the upper part of the condenser is opened so that steam for cleaning the condenser is introduced into the condenser.

The introduced steam is injected into the condenser through the steam nozzle 15 or 15 'mounted on the upper end of the condenser to clean and remove impurities in the condenser.

The cleaned impurities are discharged through the drain valve 14 or 14 'at the bottom of the condenser.

The cleaning of impurities inside the condenser may be repeated until it is determined that the temperature or pressure sensor does not require cleaning of the condenser. The overall process of valve opening and closing of the COG cooling condenser and movement of gas and steam is controlled by the controller 16.

The cleaned condenser is waited until it needs cleaning of the other condenser.

As described above, while the condenser of one of the condenser connected in parallel is washed, the other condenser is subjected to the COG cooling condensation process, the operation is not stopped due to the condenser washing, it is possible to continuously condensate COG.

During the GOC refining process by the running condenser, if the temperature or pressure sensed by the temperature and pressure sensor requires the cleaning of the condenser, the condenser in need of cleaning is washed and the cooling condensation process of COG in the washed condenser This is disclosed.

Hereinafter, a COG purifying apparatus and an automatic washing method thereof according to the present invention will be described in more detail with reference to the accompanying drawings.

1 is a view showing a COG purification apparatus according to the present invention, Figure 2 is the inside of the condenser

And it is a view showing in detail the connection structure with the outside. Hereinafter, washing of impurities in the condenser 4A in FIG. 2 will be described as an example.

The COG is first stepped up to a pressure of about 1800 mmH ₂ O in the gas blower (1),

The gas passes through an aftercooler 2 which cools it primarily. After that, after

Via the water separator 3 which is a water separator installed at the rear end of the cooler 2, the condenser

(4) in the gas / water heat exchanger to finally drop the temperature of the gas to the desired temperature

Moisture in the water is removed. Meanwhile, cooling water used for cooling COG is cooled in the water condenser 5, discharged through a cooling water outlet, and flows into the C / W inlets of the cooling condensers 4A and 4B. . On the other hand, the cooling condenser 4A, 4B is discharged from the C / W cooling condenser used for cooling the COG and flows into the water condenser.

The amount of water removed varies with the temperature of the gas, so controlling the temperature

You can adjust the amount. As a refrigerant supplied to the condenser 4A, a solution in which water and ethylene glycol are mixed 1: 1 is used. The refrigerant is supplied through a pump 6, and the refrigerant after heat exchange is cooled to a desired temperature in the water condenser 5. .

As shown in Fig. 2, two condensers 4A and 4B are connected in parallel with each other. The pressure drop measured at the front and rear stages of the condenser 4A or at the temperature sensors 7 and 8 during the COG refining operation by operating one of the two condensers 4A, or the temperature difference is greater than 150 mmH ₂ O. Is lower than or equal to 20 ° C, the valve 12 positioned at the front end of the condenser 4A and the valve 13 positioned at the rear end are shut off by the controller 16, so that the COG gas into the condenser 4A is blocked. The inflow is stopped. At this time, the front and rear valves 10 and 11 of the condenser 4B are opened so that the COG condensation cooling is stopped at the condenser 4B while the COG flows into the condenser 4B and the condenser 4A is washed. Continues without.

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When the valves 12 and 13 are shut off, the steam valve 9 located above the condenser 4A is opened by the controller 16 and steam for cleaning the condenser 4A is introduced into the condenser. . Steam is injected into the high pressure steam from the steam nozzle 15 mounted on the upper end of the condenser to wash the deposits inside the condenser.

The washed deposit is then discharged through the discharge line at the outer bottom of the condenser 4A.

As the steam nozzles 15 and 15 ', nozzles of any type, such as cone type, mist type, hollow type and flat type, may be used, and the flat type is particularly preferable in terms of impurities removal efficiency.

The condenser 4A cleaning may be repeated until the pressure drop measured by the front pressure or temperature sensor 7 and the rear pressure or temperature sensor 8 is less than 150 mmH ₂ O or the temperature difference exceeds 20 ° C. .

When the cleaning of the condenser 4A is completed, the condenser 4A waits until it is necessary to clean the operating condenser 4B while the front and rear valves 12 and 13 are blocked.

While the one condenser 4A is washed as described above, the COG flows into the other condenser 4B and the purification process is performed. When the temperature and the pressure requiring the cleaning of the condenser during the purification by the condenser 4B are sensed, As described above, the condenser 4B is washed, at which time the COG continues to cool and condense in the condenser 4A.

On the other hand, the gas which passed the condenser 4A in this way is supplied to a heating furnace via piping.

Hereinafter, the present invention will be described in detail through examples. However, the following examples do not limit the present invention.

Example 1

While passing COG gas through condenser 4A,

The production tendency of powder and impurities was identified.

The condenser 4B was closed and the COG gas was passed through the condenser 4A while operating while maintaining the temperature difference between the front and the rear of the condenser at 30 ° C. After about 30 days, the condenser 4A was lowered compared to the initial state. The speed slowed by about 30% and the pressure drop in the front and rear stages increased from the initial 50 mmH ₂ O to 150 mmH ₂ O. At this time, the average inflow of COG was 2,800 Nm ³ / hr. On the other hand, in the condenser 4A, a refrigerant in which water and ethanol were mixed in a 1: 1 weight ratio was used.

Accordingly, while slowly closing the front and rear valves 12 and 13 of the condenser 4A by the controller 16, the COG opens and closes the front and rear valves 10 and 11 of the condenser 4B. The COG was operated to enter the condenser 4B. When the valve is completely closed, the steam valve 9 installed at the top of the condenser is opened to inject steam into the condenser 4A and injects steam through the flat steam nozzle 15 inside the condenser for 1 hour and 30 minutes. The attachment substance of was washed.

Removed impurities were discharged through the drain valve 14 at the bottom of the condenser.

The condenser 4A is waited until the condenser 4B has to be cleaned after the washing is completed. By automatically washing the impurities in the condenser, the temperature drop rate and the pressure drop before and after the condenser were restored to the initial state.

Example 2

Except that the type of the nozzle for cleaning the inside of the condenser was changed as shown in Table 5, the deposit in the condenser 4A was removed in the same manner as in Example 1. The impurity removal rate in the case of using different nozzle types is shown in Table 5 below.

The removal rate of impurities was calculated by calculating the impurity adhesion area inside the heat exchanger.

TABLE 5

Nozzle type Impurity Removal Rate (%) Cone type
Mist type
Hollow type
Flat type 80-85
40-50
60-70
95-98

The apparatus and method of the present invention can automatically clean the condenser in a short time without stopping the device by automatically washing the condenser of the COG gas moisture removal device. This is very economical and efficient in terms of cleaning the condenser and operating the COG refinery.

Claims (4)

Two condensers 4A, 4B connected in parallel; Steam valves 9, 9 'located at the outer top of the condenser to supply a cleaning steam to the condenser; Steam nozzles 15 and 15 'mounted on the upper end of the condenser for injecting high pressure steam into the condenser; And Drain valves 14, 14 'mounted at the outer bottom of the condenser for discharging the washings; A shear pressure or temperature sensor 7 positioned at the front end of the condenser shear shutoff valves 10 and 12 and measuring the pressure or temperature of the coke oven gas flowing into the condenser; A rear end pressure or temperature sensor 8 positioned at a rear end of the condenser rear end shutoff valves 11 and 13 for measuring the pressure or temperature of the coke oven gas discharged from the condenser; Condenser front end shutoff valves 10 and 12 positioned at the front of each condenser 4A and 4B to regulate the inflow of coke oven gas into the condenser; And A condenser coke oven gas cooling condenser comprising a condenser end shut-off valve (11) and (13) located at the rear end of each condenser (4A) and (4B) to regulate the discharge of the coke oven gas from the condenser. The apparatus of claim 1, wherein the steam nozzles (15, 15 ') are flat type nozzles. (a) Coke oven gas passing through a gas blower (1), after cooler (2) and a water separator (3) through a condenser (4A or 4B) of one of the condensers connected in parallel. Condensation of moisture in the water; (b) the temperature of the coke oven gas entering the condenser and the coke oven gas exiting the condenser at the pressure or temperature sensors 7 and 8 at the front and rear ends of the two condensers 4A and 4B connected in parallel, or Measuring pressure; (C) When the pressure drop measured by the front pressure or temperature sensor 7 and the rear pressure or temperature sensor 8 is 150 mmH ₂ O or more or the temperature difference is measured to be 20 ° C. or less, the front end of the condenser in operation and The valves at the rear stage are closed and the valves at the front and rear stages of the condenser in the air are opened so that the cooling condensation process of the coke oven gas can be continued; (d) The steam cleaning valve at the upper part of the condenser, in which the front and rear valves are closed, is opened, and steam is injected into the high pressure steam from the steam nozzle (15 or 15 ') mounted on the upper part of the condenser. Washing the attachment of the; (e) discharging the washed deposit through the discharge line; And (f) steps (b) to (b) until the pressure drop measured by the front pressure or temperature sensor 7 and the rear pressure or temperature sensor 8 is less than 150 mmH ₂ O or the temperature difference is greater than 20 ° C. e) repeating the step of washing the internal deposits of the condenser. 4. The method of claim 3 wherein the steam nozzle (15) or (15 ') is a flat nozzle.

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