JPS5943510B2 - Method and apparatus for separating a mixture of tar and ammonia liquid produced during the production of coke from fine coal - Google Patents

Abstract

Tar and coal fines are separated from ammonia liquor in a coke making operation by a series of settling steps including one in which a foam is physically removed from the surface area of a decanter and placed in a separate decanter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for separating a mixture of tar and ammonia liquid from a coke oven plant.

Coarse components are usually separated in a primary separator or decanter;
The use of heat, for example heat of the separated ammonia liquid, causes it to be continuously separated into tar and ammonia liquid.

Devices for separating tar from ammonia liquid are known, for example, from DE 917 388 and DE 935 020 and DE 10 57 721.

- The tar collection tank of the tar separator has a slope at the bottom and is surrounded by an ammonia liquid storage tank.

The tar discharge pipe can be installed deep in the inner part of the tar collection tank.

Other devices for separating tar and ammonia liquid are designed according to the same principle and are described, for example, in West German Patent Publication No. 1044
342 and DE 1156823, the latter of which works without prior separation of the heavy tar.

If necessary, and if there are special requirements regarding the tar purity, such as solids and water content, two tar separators can be connected in series as described in the DE-OS.

Temperatures above 100° C. and elevated pressures have also been used for the separation (see German Patent Specification No. 10 20 349).

These known devices are installed in coke oven plants where coal with a moisture content of 5 to 10% is charged into the oven.

If this type of coal is not finely ground, separation of tar and liquid phase by known equipment is easy.

The gases released during coke production usually contain about 30% of the weight of the coal in the form of organic volatiles, along with a significant amount of moisture.

This gas is sprayed with water or a circulating cleaning fluid to remove entrained solids, generally in the form of tar.

The main gas collection tubes run the length of the battery, each inlet tube having a spray and an additional spray device approximately three furnaces apart.

The main suction pipe connected to the main collection pipe is usually filled with tar and “liquid”
Contains about 25% by volume of a mixture of.

The tar-containing liquid is taken to a decanter where it is separated into a bottom tar and a decanted aqueous ammonia solution.

A portion of the aqueous solution is recycled for use in the spray.

U.S. Patent Nos. 2018377, 2697067, 2775541, 2799678 and 2937
No. 130 is also cited as a reference.

Recently, the industry has turned to finely ground predried or preheated coal with very low moisture content to increase coking rates and increase battery capacity.

Known devices and methods for separating mixtures of tar and ammonia liquid have proven inadequate for use with finely ground preheated coal because they do not achieve the complete separation necessary for satisfactory operation.

Generally, when using known equipment, the water content of the tar is often too high to be useful.

It is also not permissible for the liquid phase to contain tar.

This is because when the ammonia liquid is returned to the main collection tube of the battery, the spray nozzle becomes clogged and the excess liquid deposits its tar in the processing equipment.

The tar condensate and ammonia liquor which form during the charging of pulverized and predried or preheated coal into the furnace chamber tend to form very stable suspensions and foams which are harmful to the operation, and which can be treated by known equipment and methods. cannot be separated sufficiently.

Finely dispersed solids, with a tendency to form suspensions and bubbles
This is facilitated in particular by the presence of tar-coated coal particles suspended in the ammonia liquid, forming suspended dispersions or bubbles with air and other gases.

In particular, the presence of ammonium and chloride ions appears to lead to the formation of surfactants, which promote suspension and foam formation.

For the separation of foams and suspensions, the liquid stream leaving the tar separator was used, optionally under pressure, application of heat and/or addition of salts of polyhydric acids with a colloidal separating effect.

In such cases considerable additional costs in equipment, energy and chemicals are required.

The object of the invention is to separate suspensions and foams from the mixture of tar, ammonia and condensate obtained during coking of finely ground pre-dried or pre-heated coal without additional equipment costs and consumption of energy and chemicals. to obtain a tar phase and a liquid phase, the liquid phase can be circulated through the main collection tube and used satisfactorily for cooling the hot gas obtained during coal coking, and furthermore, the excess liquid can be disposed of. It is to obtain.

The suspension contains tar as well as fine coal, often entrained in foam.

The suspension and foam problem is solved by removing suspended matter and floating foam from the surface of the ammonia liquid in a primary decanter and passing it to a foam separation vessel.

The ammonia liquid phase in the foam separator is then sent back to the primary decanter.

The most advantageous temperature range for this last separation is 70-90°C.
It is ℃.

Although the foam and/or suspension is known as "floating tar," it is clear from the analysis in the following table that "floating tar" actually contains a large amount of pulverized or partially degassed coal. .

Sample: Moisture 48.4% Tar *19.1//Coal or solid *32.5// Water or liquid phase: pH value 8.57 Chloride 2.86% Tar-coal phase: Moisture 40.4 Weight %Quinoline solubility (dry) 65.02 Volatile content (dry)
37.50 //Ash (dry)
6.19 carbon (dry), 31.39 hydrogen (dry)
4.43 Sulfur (dry) 1.07 *Calculated from Q, ■, amount The Tanilhu coal phase is processed to remove quinoline soluble tar for further analysis of coal and other solids.

Sieve analysis: (cumulative %) +20 mesh 1.2 +5Q 〃7.0 -1-70 u 9.3+10
0// 12.8+200//
26.7-200//
73.3 Volatile content (dry) weight% 21.9
0 Ash tt tt 8.42 Carbon u tt 78.83 Hydrogen tt tt 4.22 Sulfur 〃〃1.05 According to the invention, a mixture of tar and ammonia liquid can be finally separated without additional consumption of energy and chemicals. This makes it possible to work satisfactorily,
Blockage of subsequent devices is avoided.

It is clear that surface or interfacial disturbances must be avoided as much as possible.

That is, all unnecessary movements must be avoided when removing suspensions and foam and returning the ammonia solution.

The primary separator for removing suspension and foam is equipped with an adjustable overflow port on its back wall through which suspension and foam can flow out.

The suspension and foam are then sent from the downcomer to the final separator.

In this way the liquid phase in the primary separator is hardly disturbed.

Additional equipment (rake and attachment of the primary decanter) can be designed with relatively small dimensions with this new method.

The condensate stream exiting the primary decanter containing ammonia liquid and tar may be sent to one or both of the primary separator and the final separator.

The tar phase separated from the primary separator is usually sent to a final separator from which pure tar can be processed.

The aqueous ammonia separated from the primary tar separator water tank is also directed to the final tar separator water tank before further treatment.

This means that two tar separators are usually connected in series for the water and tar streams respectively.

Very low suspended solids content in the final tar separator 2-3
% of tar can be separated from water.

It is advantageous to provide two primary decanters connected in parallel to the tar and water flow and two tar separators connected in series.

The tar separator, primary decanter and foam separator may be equipped with conventional controls and devices to facilitate adjustment and variation of liquid level.

Next, the present invention will be explained with reference to the drawings.

A mixture consisting of tar, ammonia liquid and condensate is fed from a pipeline 1 and is distributed into two branches 2 of the dip tube, through which the mixture passes through two primary decanters 3 where a first pitch sand separation takes place. reach.

6 Pitch Sand” is tar and fine solid particles (coal).
and represents a heterogeneous coagulum of water.

The mixture flows under the partition wall 14 to the rotating screen drum 5.

The aqueous condensate and tar pass through the holes in the drum and flow through conduits 6, 7.8 to the first tar separator 9.

The tar and pitch sand in the water phase are removed from the scrin drum 5.
is removed from the drum by a scraper (not shown) and deposited at the bottom of the primary decanter 3, where it is dredged by a device 10 formed as a scraper conveyor.

The scraper comparator sends the pitch sand to the discharge hole 11.

Suspension and foam are collected on the surface in front of the partition wall 14 and are conveyed by the moving scraping plate 12 over the weir 13 via the conduit 15 to the foam separator 16 .

The foam separator comprises a separate device designed as a drainage chamber 17 with a height-adjustable weir (not shown).

The pitch sand settles and is removed by the bottom scraper 18 and sent to the discharge hole 19.20.

Floating suspensions and/or bubbles are removed by moving scraping plate 12 (
(not shown) from the feed conduit 23 to the discharge holes 21 and 22.

The separated water is removed from the drainage chamber 17 via conduit 24.25 and returned to the primary decanter 3.

The water and tar mixture exiting conduit 8 is sent to primary separator 9, in which the water and tar interface is indicated at 26.

Separated water, the surface of which is shown at 29, extends over the weir 30 and into the groove 31.
and enters jacket chamber 33 via conduit 32.

This jacket chamber has a bottom 35, an inclined part 36 and a cylindrical wall 3.
Blocked by 4.

The sloping portion 36 of the tar collection chamber 28 opens into a tar outlet 37 that extends outward from the bottom 35 of the jacket chamber 33 .

The pitch sand collected on the slope is sent by a scraper conveyor 38 and discharged from an outlet 39.

Additionally, the tar separator 9 is equipped with a discharge conduit 40 for removing suspended solids at the interface 26.

The tar from the collection chamber 28 is passed through the conduit 4 to the collection chamber 42 of a secondary tar separator 43 formed similarly to the primary tar separator 9.
Sent by 1.

This separator comprises a jacket chamber 44 closed by a cylindrical wall 45, a bottom 46 and an inclined wall 47.

Final separation takes place in the tar collection chamber 42, and the settled pitch sand is taken out from the outlet 48 by a scraper conveyor 49 and discharged from the outlet 50.

The tar-water interface is indicated by 51, and the water surface is indicated by 52.

As an additional device, the final tar separator 43 is provided with a discharge conduit 53 for removing the emulsion above the interface 51.

The tar with a moisture content of 2-3% is sent via conduit 54 to various points of use.

The water collected in the jacket chamber 33 of the tar separator 9 is conveyed by a conduit 55 to the jacket chamber 44 of the final separator 43.

A valve is provided in conduit 55 to control the diversion of the flow sent by conduit 56 to the separation chamber 57 of tar and water in order to allow complete separation and equilibration of the two separators.

The separated water flows over weir 58 to groove 59 and into conduit 60.
enters the jacket room 44.

The water is finally discharged through conduit 73 and returned to the four-battery collection main.

This water no longer contains coal particles or other suspended solids that would block the liquid nozzle of the collection main.

The water that is distilled during the coking process and enters the tar separator as condensate leaves the final tar separator 43 via channel 59 and condensate discharge pipe 61 and is used for other processing.

Water levels 29 and 52 of the two tar separators 9 and 43
The tar separator is equipped with adjustable weirs 62 and 63 to provide an additional means of collecting small amounts of suspension and foam from the tar separator.

Conduits 64 and 65 are connected to an auxiliary foam separator 66 with a septum 67 .

After a certain residence time, the water separated from the suspension and foam passes under the partition 61 and enters the collection tank via the outlet 68 and the conduit 69.

When the water has settled sufficiently, it is sent to the primary decanter 3.

The pitch sand sinks to the bottom and scraper conveyor device γ0
is discharged from the output lower 1.

Outlet pipe 72 is provided as a safety flow device.

FIG. 2 shows an advantageous embodiment of the movable scraping plate 12.

The conveyor 101 includes a primary decanter 3 and a foam separator 16.
It is supported on rolls 102 and 103 with agitators (not shown) in 66.

As shown in the figure, a large number of approximately L-shaped scraping plates 12 are arranged on the conveyor 101, and these scraping plates are rotatable so as to remain almost vertically stationary when moving the foam and suspended matter to the left in the drawing. Fixed.

Upon hitting the slope 105 of the weir 106, the suspended matter and foam travel down the chute 107 to the foam separator 16 by gravity.

The scraping plate 12 then moves to the top of the conveyor.

[Brief explanation of the drawing]

FIG. 1 is a functional explanatory diagram of the device according to the present invention, and FIG. 2 is a longitudinal sectional view showing one embodiment of the scraping device. 3...Primary decanter, 9,43...Tar separator, 16,17...Bubble separator.

Claims (1)

Claims: 1. Coke from fine coal, separating coarse particles which tend to increase surface suspension and suspended tar foam in a primary separator from a mixture consisting of tar, ammonia liquid and condensate. In this method, suspended solids and foam floating on the surface of the ammonia solution are mechanically removed in the primary separator, sent to the foam separator, and the tar and ammonia solution are separated. A method for separating a mixture of tar and liquid ammonia resulting from the production of coke from fine coal, characterized by allowing the mixture to remain in a foam separator for a sufficient period of time to separate into a phase and a liquid phase. 2. The method of claim 1, wherein the residence time of the foam in the foam separator is at least 2 hours. 3 To enable secondary separation of tar and ammonia 1
2. A method as claimed in claim 1, in which heat is supplied to the secondary separator. 4. The method according to claim 1, wherein the tar phase and the liquid phase are removed separately from the foam separator. 5 In a device that separates ammonia liquid generated during coke production from fine coal into a tar phase and a liquid phase, a primary separator that accommodates the ammonia liquid, a device that removes bubbles floating on the surface of this separator, and a foam Tar produced when producing coke from fine coal, characterized by comprising a separator, a device for sending foam from the primary separator to the foam separator, and a device for separately taking out a tar phase and a liquid phase from the foam separator. A device that separates a mixture of ammonia and ammonia liquid. 6. Apparatus according to claim 5, comprising at least one additional separator for separating tar from the ammonia liquid. I have a number of moving scraping plates installed on a conveyor, which can adjust its vertical position, so that the scraping plates move in different horizontal planes depending on the level of the suspension. The device according to claim 5. 8. The device according to claim 7, which is installed in a first order decanter.