US3432396A

US3432396A - Method of clearing tar accumulations from a coke-oven collector main

Info

Publication number: US3432396A
Application number: US563481A
Authority: US
Inventors: Homer B Coleman; Robert E Gardner Jr
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1966-07-07
Filing date: 1966-07-07
Publication date: 1969-03-11
Anticipated expiration: 1986-03-11

Description

March 11, 1969 METHOD WATER COKE*OVEN COLLECTOR MAIN Filed July 7. 1966 FL us/mva L/OUOR MAKE-UP RAW cox: ave/v 64.5 7 00 L 670/? 4mm L E 1 Z ar- /waucr b RECOVER) FL USHHVG BATTERY 0/-' Jag 2 L/OUOR 00x5 ave-ms L ,OUOR 0mm STRAI/VER 74/? k sgPA/m no/v v TAR CFEOSO 15%,2 G CREOSOTE 80770415 STORAGE BOT-TOMS l4-A0UE0US AMMONIA INVENTORS HOME I? B. COLEMAN and ROBERT E. GARDNER,JL

Attorney United States Patent 3 Claims This invention relates to an improved method of clearing tar accumulations from a coke-oven collector main A conventional battery of byproduct coke ovens includes a collector main through which volatile matter and gases pass after their release from the coal. The collector main is flushed continuously with flushing liquor, which is mainly aqueous ammonia. In this manner most tar is carried from the main and recovered for further processing. Nevertheless some heavy viscous tar accumulates in the main, and over a period partially clogs it. The usual practice is to clear out such accumulations manually with lances or like at approximately three-month intervals. This operation is both time-consuming and hazardous and causes air pollution.

An object of our invention is to provide an improved method of clearing tar accumulations from a collector main and avoiding the difficulties usually encountered.

A more specific object is to provide a method of clearing tar accumulations from a collector main in which creosote bottoms recovered from coal tar are added to the flushing liquor periodically as needed.

In the drawing:

The single figure is a diagrammatic layout of a cokeoven battery in which the collector main is cleared of accumulations by our method.

The figure shows a conventional coke-oven battery and collector main 12. The main receives volatile matter and gases released from the coal in the coking process. A pump 13 continuously supplies flushing liquor from a vessel 14 to one end of the main. This liquor passes through a conventional strainer 15 between the pump and main. Tar and liquor from the main go to conventional tar separation equipment 16, from which the liquor returns to vessel 14. Tar from the separation equipment leaves the system for further processing. Raw gas from the main goes to byproduct recovery equipment 17. When make-up flushing liquor is required, water is added to the flushing system by opening a valve 18. Products from the byproduct recovery equipment 17 leave the system for further processing.

When a tar deposit accumulates in the main 12 to an extent that cleaning is required, we introduce creosote bottoms to the main via the flushing liquor. We obtain the creosote bottoms at the byproduct recovery equipment 17. A pump 19 forces a stream of the creosote bottoms into the flushing liquor between the strainer 15 and main 12. The creosote bottoms have a boiling range (American Wood Preservers Association distillation) of about 290 to 355 C. (40 percent residue at 355 C.). They are at a temperature of about 190 to 210 F. or preferably about 200 F. when we introduce them to the liquor. We include them in proportions of about 0.5 to 0.8

percent by volume of the flushing liquor, or preferably about 0.75 percent. During the cleaning operation we reduce the flushing liquor pump pressure from its normal level of about 44-45 p.s.i. to about 3638 p.s.i. The pressure at the liquor sprays on the battery remains at the normal 15 p.s.i. The liquor flow rate is approximately 1120 to 1250 gallons per oven hour, or preferably about 1200 gallons. We add the creosote bottoms continuously for a period of about 24 to 48 hours or preferably approximately 32 hour, and at a rate of about 6.0 to 10.0 i

or preferably approximately 9.0 gallons per oven hour.

Although the creosote bottoms are not soluble in the flushing liquor, they are a solvent for tar which has accumulated in the main. Before one test we inspected the main and found that it contained a large volume of viscous tar. We introduced creosote bottoms according to the foregoing preferred standards. We inspected the mains 24 hours later and found them completely free of tar, except for small quantities at the extreme ends of the main. The tar at these locations was soft and easily removed.

While we have described only certain preferred ways of practicing our invention, it is apparent modifications may arise. Therefore we do not wish to be limited by the disclosure, but only by the scope of the appended claims.

We claim:

1. In a byproduct coking operation in which volatile matter and gases release from coal pass through a collector main, and substantially aqueous ammonia flushing liquor is introduced continuously to said main and carries away most of the tar, but some heavy viscous tar accumulates in said main over a period, the combination therewith of a method of clearing accumulations of tar from said main comprising introducing creosote bottoms to the flushing liquor going into said main in an amount to provide about 0.5 to 0.8 percent by volume of creosote bottoms in the flushing liquor, the creosote bottoms being at a temperature of about to 210 F.

2. A combination as defined in claim 1 in which said creosote bottoms have a boiling range (American Wood Preservers Association distillation) of about 290 to 355 C. (40 percent residue at 355 C.)

3. A combination as defined in claim 1 in which the creosote bottoms are introduced continuously over a period of 24 to 48 hours.

References Cited UNITED STATES PATENTS 167,755 9/1875 Fox 2012 1,556,248 10/ 1925 Ohlwiler 13440 1,744,463 1/ 1930 Gravell 134-38 1,924,163 8/1933 Miller 208-39 1,981,626 11/ 1934 McCloskey 208--39 FOREIGN PATENTS 10,573 5/ 1908 Great Britain.

1,343,981 10/ 1963 France.

NORMAN YUDKOFF, Primary Examiner. D. EDWARDS, Assistant Examiner.

US. Cl. X.R. 134-39; 202-241

Claims

1. IN A BYPRODUCT COKING OPERATION IN WHICH VOLATILE MATTER AND GASES RELEASE FROM COAL PASS THROUGH A COLLECTOR MAIN, AND SUBSTANTIALLY AQUEOUS AMMONIA FLUSHING LIQUOR IS INTRODUCED CONTINUOUSLY TO SAID MAIN AND CARRIES AWAY MOST OF THE TAR, BUT SOME HEAVY VISCOUS TAR ACCUMULATES IN SAID MAIN OVER A PERIOD, THE COMBINATION THEREWITH OF A METHOD OF CLEARING ACCUMULATIONS OF TAR FROM SAID MAIN COMPRISING INTRODUCING CREOSOTE BOTTOMS TO THE FLUSHING LIQUOR GOING INTO SAID MAIN IN AN AMOUNT TO PROVIDE ABOUT 0.5 TO 0.8 PERCENT BY VOLUME OF CREOSOTE BOTTOMS IN THE FLUSHING LIQUOR, THE CREOSOTE BOTTOMS BEING AT A TEMPERATURE OF ABOUT 190 TO 210*F.