CA1060834A

CA1060834A - Process and apparatus for the separation of so-called float tars

Info

Publication number: CA1060834A
Application number: CA239,667A
Authority: CA
Inventors: Heinz Grulich; Ernst Otte
Original assignee: Bergwerksverband GmbH; Didier Engineering GmbH
Current assignee: Bergwerksverband GmbH; Didier Engineering GmbH
Priority date: 1974-11-16
Filing date: 1975-11-14
Publication date: 1979-08-21
Also published as: JPS5171323A; DE2454394A1

Abstract

PROCESS AND APPARATUS FOR THE
SEPARATION OF SO-CALLED FLOAT TARS

ABSTRACT OF THE DISCLOSURE
The so-called float tar which floats on the crude tar in tile tar separator and is a bothersome by-product is separated from the mixture of crude tar and water formed in the collector of the separator of a cok-ing installation and the separated float tar is then sub-jected to comminution and homogenization whereupon the homogenized product may then be processed either separately or together with the bulk of the tar.
An installation for use in the process comprises a tar separator, an open circulation or collector vessel forming part of said separator, a channel associated with said tar separator, means provided in said circulation vessel for separating the float tar from the bulk of the crude tar and passing it into said channel,and a comminut-ing and homogenizing device which communicates with said channel through a grade drop.

Description

~iO~34 BACKGROUND OP THE INVENTION
~ hen filling coking ovens with coal of certain properties, for instance of low moisture content or with preheated coal, a tar frequently forms during the coking operation which is intermixed with solids, water and gas bubbles and which floats in the collector and in the tar separator as a frothy mass on the rinse water. This tar, called herein ~Ifloat tar"
passes into the tar separator together with the crude tar and must be re-moved as an undesirable by-product. The use of this float tar is difficult and its disposal, for instance by burning, is laborious and expensive.
It is therefore an object of the invention to provide for a process and apparatus whereby this undesirable float tar can be processed comparative-ly easily and whereby its properties can be modified so that such processing can be effected without special effort together with the remainder of the tar.
SUMMARY OF THE INVENTION
This object is accomplished by separating the float tar from the mixture of crude tar and water present in the collector of the coking in-stallation and subjecting the separated flotation tar to comminution and homogenization3 whereupon the homogenized product may then be processed either separately or together with the bulk of the tar.
2Q Another feature of the invention is an apparatus for use in this process which comprises an open top circulation vessel forming part of a coking installation, a channel associated with said circulation vessel, means for separating the float tar as appears in the tar mixture received in the circulation vessel from the coking installation from the bulk of the crude tar and water, and for passing the separated float tar into said chan-nel, and comminuting and homogenizing means which are in communication with said channel and means for processing the high viscosity tar formed in the homogenizing device separately or together with the bulk of the crude tar.
BRIEF DEscRIpTIoN OF THE DRAWINGS
Figure 1 is a schematic side view of a tar separator with the de-vice of the invention;
Figure 2 is a plan view of the device of Figure l; and ~06083~

Figure 3 is a cross-section through lines A - A through the separator of Figure 1 illustrating also the co~minuting device.
DESCRIPTION OF THE PREFERRFD MBODIM~NTS
With specific reference to Figure 1 it will be noted that the float tar occurring in the tar separator and specifically in the circulation vessel w~ich receives the tar from the coking installation is skimmed off and over by means of a bucket wheel 2 into the channel 3 which floats on the vessel 1. From the channel 3 the tar flows by gravity into the comminution device 4. -Residual water with minor amounts of tar after separation of the float tar is passed across the dam 5 into the discharge tube 6 and may be recirculated into the collector or circulation vessel.
In place of the bucket wheel, a suitable dam may also be employed over which the float tar can flow or any similar conveyor means may be used by which the float tar is skimmed off the mass of the crude tar, such as a ribbon scraper. As a precaution the tar separator is provided with an addi-tional da~ 7 which will hold back any float tar that may have escaped the bucket wheel or other separator device.
The crude tar which has dropped to the bottom in the tar separator as conventional is then moved in known manner out of the tar separator by means of a scrape conveyor, not further illustrated. The tar separator is normally provided with an outlet opening in about the center level of its height through which the lower viscosity crude tar can continuously drain from the tar separator. The float tar skimmed into and collected in the channel 3 then flows by a gravity drop into the comminution device. The comminution device may consist of a mill or power mixer or any of the usual homogenizing machines. The float tar is subjected to vigorous pressure and gravity forces so that the enclosed gas bubbles are displaced and the solids can be formed into a homogeneous high gravity mass. In any case this step completely destroys the dreaded float properties of this part of the tar mixture. The tar now will have the property of ordinary crude tar and can easily be combined with the bulk of the tar for further processing, or can also be pTocessed separately.

1~601!334 The following example will further illustrate the invention.
During the coking of 5 t coal per day entering the coking chamber with a water contents of 1% by weight of water, an amount of 200 t tar es-capes from the chambers in the gas collector. This tar consists of about 175 t ordinary crude tar and 25 t float tar.
By addition o rinse water in the collector which has a cross-section of 600 mm, the tar mixture is caused to flow downwaTd in the tar separator which is formed as an open top circulation vessel. In the tar separator the accumulated flow tar is skimmed off by the bucket wheel 2 which has a total diameter of 1,000 mm and is passed into the channel 3 which has a width of 800 mm. The float tar then flows downstream in the inclined channel 3 into the turbo mixer 4. From this mixer it is received in a continuous operation as a high gravity liquid tar which can be combined readily with the bulk of the crude tar.
The remaining crude tar is removed from the tar separator in a continuous operation by a scrape conveyor while the rinse water is recir-culated through duct 6 into the collector.
Nithout further analysis, the foregoing will so full reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
~hat is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for the separation of so-called float tar comprising separating the float tar containing solids, water and gas bubbles from the mixture of crude tar and water formed in the collector of a coking installation and subjecting the separated float tar to a comminution and homogenization whereupon the obtained high viscosity tar may then be processed either separately or to-gether with the bulk of the crude tar.

2. The process of claim 1 wherein the bulk of the crude tar and any remaining water after separation of the float tar are returned to the coke oven collector.

3. The process of claim 1 wherein the float tar after separation is passed by gravity drop to the area where it is sub-jected to comminution and homogenization.

4. The process of claim 1 wherein the separation of the float tar is effected by skimming off the float tar from the top of the stream of the bulk of the crude tar and passing the float tar to an area where said comminution and homogenization is effected.

5. The process of claim 4 wherein any residual float tar which has not been removed in said skimming step is separated by an overflow means arranged in the flow path of the bulk of the crude tar.

6. An installation for the separation of float tar occurring in the tar separator of a coking plant where an ammonia water-crude tar mixture is received from a collector chamber of the coking plant, said installation comprising an open-top tar separator for receiving and separating said float tar and said ammonia-water mixture from said crude tar;
a channel in said tank separator normally floatingly supported on said ammonia-water mixture and extending across said tank separator;
skimming means in the form of a bucket wheel revolving in said tank separator for skimming the float tar from the ammonia-water mixture flowing in the tank separator and for passing the separated float tar into said channel; and a comminution and homogenizing means provided at one end of said channel, for receiving and processing said float tar, whereby a high viscosity tar is formed from said float tar by the comminution and homogenizing means which then is recovered separately or together with the bulk of the crude tar.

7. The installation of claim 6 wherein said channel extends at an incline from said tank separator to said comminution and homogenizing means, whereby the separated float tar is gravity-fed to said comminution and homogenizing means.

8. The installation of claim 6 wherein a dam is provided downstream of said bucket wheel and channel, said dam extending across the tar separator in order to remove any residual float tar.