US2012832A - Decoking lance - Google Patents

Description

ug- 27, 1935- c. E. RHEIN E1- AL 2,012,832

DECOKING LANCE Filed Aug. 51, 1932l 2 sheets-Sheet 2 ||\1vEr-rroRS CHARLES E. PHE/N .JA/V155 JT BRUTO/v Patented Aug. 27, 1935 UNITED STATES PATENT OFFICE DECOKING LANCE Application August 31, 1932, Serial No. 631,167

15 o1aims. (o1. 15s-27.4)

This invention relates to an apparatus for burning carbon and other combustible deposits from tubes and is especially'adapted for use in removing the deposit of carbon from the tubes of oil cracking'stills.

An object of this invention is to provide an apparatus for this use which shall embody means for heating the cokes to kindling temperature. Another object of this invention is to provide an apparatus of this type wherein provision yis made for mixing air with the oxygen which serves to support the combustion or for otherwise diluting the oxygen so that the chemical activity thereof and, consequently, the probability of undesirable cutting or burning action on steel tube walls, is reduced. Yet another object is to provide means Afor cooling the apparatus and for indicating when high temperatures are approached in the tube. Further objects of our invention are to provide a simple, rugged and inexpensive apparatus-fonv Fig. '2 is a diagrammatic illustration of theapparatus taken in section on the line 2-2 of Fig. 3 and including the handle as well as the head.

Fig. 3 is a section on the line 3 3 of Fig. 1.

Fig. 4 is a section o n the ,line 4--4 of Fig. 1.

Fig. 5 is a section on the line 5-5 of Fig. 1.

Fig. 6 is an end view of the apparatus and Fig. 7 is a section of the handle taken on the line 'I-'l of Fig. 2.

In the drawings there is illustrated an apparatus embodying one form of our invention. 'Ihis apparatus is for convenience hereinafter called a lance; the lance consists of a head portion and a handle portion. The head portion has a tube I which is conveniently made of copper and has an outside diameter about 1A inch less than the inside diameter of 'the tube to be cleaned. Ihis outer tube or casing serves to center the lance in the tube which is being cleaned. However, we

have found that it isl not necessary that the diient means such as the set screw I2. The base is provided with a number of grooves for receiving fuel tubes I2 and the water' tubes I3 and I4. Itis also provided with bores I and I6, the former passage. The oxygen passage I6 terminates at an annular groove I'I forming an oxygen distributing space. An oxygen tip holder 2I is secured in the base adjacent the oxygen distributing space. A

forming an air passage and the latter an oxygen 5 plurality of oxygen tips are mounted in this holder 10 of the oxygen tip holder and is in communication with the air passage I5. This tube is prov vided with a plurality of holes 32 and slits 33 fo'r permitting air to escape to the interior of the lance. Part of this air is drawn in to the oxygen tips through holes in the injectors 24. The /purpse of mixing air with oxygen is to dilute the oxygen so that the danger of burning or cutting of the tube walls is minimized. While we could 25 use other materials than air to dilute the oxygen, air serves the purpose very Well and is the preferred diluent. It would be possible to dilute the oxygen at places other than the injectors, for example by a single iniector in the oxygen supply v line. We prefer to dilute the oxygen to concentrations below 90% and have found a concentration of 87% very suitable. i A In order to heat the deposit to kindling temperatures we provide a plurality of fuel tips 4I. In the drawings we have shown three of such tips. We may burn any type of gaseous fuel in these tips, such yas acetylene or ordinary illuminating gas, but We have found butane and/or propane particularly Well adapted for such use. "l0

The fuel gas is supplied through a. pipe 42 forming a part of the handle and is led to -a header 43. From the header 43 fuel supply lines I2 lead to the fuel tips 4 I In order to prevent the lance from becoming 45 overheated we provide a water jacket formed by welding or otherwise securing a member 6I to the interior of the tube near the extreme end. The Water is supplied through the inlet I3 which extends to the outer end of the water jacket and is removed through the outlet I4. The inlet and the outlet continue along the handle, the inlet being connected to a suitable source of supply and the outlet discharging where the dlscharge will be under observation. Thus during i the operation of the device the discharge can be watched and if it tends to steam or boil the operator will be aware the temperatures within the tube are becomingso high that care must `be used in order to prevent damage to the tube.

walls.

'Ihe handle should be long enough to extend the Ylength of the tube to be Vcleaned leaving a suflicient length outside the tube for convenience in operation. The handleis formed by a tube 1| supplying air a tube 12 supplying oxygen, a tube. 13 supplying fuel, and tubes 14 and 15 serving as the water outlet and inlet. These tubes are held together in any suitable manner, as by a clamp 16.

The method of cleaning cracking stills with the improved device disclosed in this application is as follows: the still is prepared for cleaning in the usual manner. While various methods of preparing a still for cleaning are practiced the following isv believed to be representative. 'Ihe now of oil (topped crude or other cracking stock) through the still is stopped and a charge of gas oil is pumped through the still for a period of three hours. 'Ihe cracking temperature (say 810. ll'.) and pressure (say 1400 lbs.) at the inlet being maintained. 'I'he flow of gas oil is then stopped, the furnace tire shut of! and superheated steam at 450lF. is admitted to the system, pushing all the oil out. This steaming is continued for several hours to make certain all vapors and liquidshave been thoroughly'iremoved so that it will be safe to remove the junction boxes or return bend plugs; this operation being known as unheading. As soon` as the still has cooled down 'the junction boxes are unheaded. Where exceptionally heavy coke deposits are apt to be encountered, additional steaming of the heaviest coked tubes may be advisable. A junction box torch is then brought up'and the junction boxes l on several rows of tubes are cleaned so that the decoking operations can start. A suitable june-- tion box torch is illustrated in the patent to W. T. Davis, No. 1,901,803, dated March 14, 1933, or the lance described herein may be used to decoke the junction boxes sulciently to afford easy entrance to the tube proper. In the case of removable return bends, these are lowered to the ground for decoking'. As soon as the junction boxes are cleaned the decoking. lance is brought into use. The fuel is turned on 'and is lighted at the fuel tips. The lance fis inserted into the tube 8nd,'.v

oxygen and air turned on. The carbon is kindled by the fuel and burns in'the presence of oxygen. If the proportion of tarry matter in the coke is low the coke'spawls and is blown out of the tubo by air from tube 3|. Inthiswaythere is no dan- `g erthatthecarbonwillburnincontactwiththe t'ube thereby damaging the tube walls. To further minimize danger that thegoxygen will cut or burn the tube walls provision is made for diluting the oxygen.A 'Ilie preferred method of diluting the oxygen is by adding air to the oxygen through the injectors 2l, although it is evident thatwe coulduse other gases the dilute the ongen and could dilute the oxygen at other places than shown. lThe fuel serves to bring the coke to kindling temperature and also to reignite the coke should this become necessary. Moreover in case a patch of coke is left adhering to the tube it can be burned 4on in a subsequent pass through the tube. -We have found that .the heat from the fuel tips does not add appreciablv to the relatively intense heat generated by the burning carbon deposit in the tubes but that the use ofthe apparatus is greatly facilitated by the use of such fuel tips which serve toprovide pilot flames. IDuring the operation of the lance water is circulated to the jacket at the end of the lance and this serves to cool the lance. It also servesas an indication of the temperatures maintained within the tube since the operator can observe whether or` not the discharge from\A the outlet is boiling. Thus the operator has two means of telling whether the lance is operating properly. In case of failure to spawl there will be an internal evolution of heat close to the end of the lance which will cause the water to approach the boiling point and also the lance will be unable to pass the carbon which does not spawl from the tube walls and failure of the lance to advance at a uniform rate indicates unsatisfactory Ving conditions. y l

It is desirable to place screens and/or a water sprayat the exit end of thetube being decoked,

operatso as to prevent ilyingparticles of naming coke l from causing damage. t

While we have disclosed one specific embodiment of our invention we do not limit ourselves to the particular type of apparatus shown: numerous modifications within the ambit of our invention will be obvious tothose skilled in the We claim:

1. Apparatus for burning deposits from the in,

terior of tubes comprising a cylindrical member adapted to engage the interior of said tubes, a' plurality of nozzles ilxed with respect to said cylindrical member for -forming jets of oxygen, said nozzles being arranged with their ends `diverg'ing outwardly and lying in planes at an oblique angle to radial planes passing through the axis of said cylindrical member, and means within said cylindrical member for supplying oxygen to said nozzles.

2. Apparatus for. burning the deposit from the interior of tubes comprising a plurality of oxygen tips so arranged to form jets of oxygen arranged to imping'e upon thedeposlt, .a conduit-for supplying a jet of air longitudinally 'of thel tube, a

casing surroundingsaid tips and 'said conduit,

jets to impinge upon the deposit with a swirlingy motion, at least one burner for supplying fuel for heating the deposit, a conduit' for supplying a -blast ofair longitudinally of the tube and means for supporting the oxygen jet forming means, the er and the air blast conduit in relatively fixed tion. f

6. 'Apparatus for removing carbon from tubes comprising a plurality of-diverging oxygen tips, at least one burner, a casing provided with a cooling chamber surrounding said tips and lburner and adapted to engage the tube and means for supplying cooling .fluid to said casing. l

"1.l In an apparatus for removing deposits from the interior of tubes, the combination with a plurality of diverging oxygen tips, at least one. burnf- 75 er, a casing surrounding said tips and adapted to engage the tube,.means for supplying fuel to the burner and means for supplying oxygen tothe tips, said last mentioned means including means for diluting the oxygen. i

8. Apparatus for removing 'a combustible deposit from the interior of tubes comprising a base, a plurality of diverging oxygen .tips mounted on said base, means for supplying an air blast mounted on said base centrally of said plurality of oxygen tips, a jacket surrounding said tips and secured to said base means for supplying a cooling fluid to said jacket, and means for supplying air from said air blast supplying means to said oxygen tips for diluting the oxygen.

9. Apparatusv for removing combustible deposits from the interior of tubes comprising a base, a plurality of oxygen tips mounted on said base, said base being provided with conduits for supplying oxygen to said tips, means for supplying .an air blast moun'ted centrally of said plurality of oxygen tips-and extending forwardly of the ends thereof, a jacket secured to said base and extending forwardly at least to the ends of said tips and means for supplying a cooling fluid to said jacket.

l0. Apparatus for removing combustible deposits from the interior oi tubes comprising a base, a jacket surrounding said base and extending forwardly thereof,' a plurality of oxygen tips arranged substantially in a circle within said jacket, means connected to said base for supplying oxygen to said tips, and means for supplying `air to the interior of said jacket;l said means for supplying oxygen to said tips including an injector means betweenthe tips and the lbase for diluting the oxygen.

11. Apparatus for removing combustible deposits from the interior of tubes comprising means provided with orifices for forming a plurality of oxygen jets,'said means being so arranged that thejets impinge upon the deposit to be removed, at least one burner means adapted to heat ,said deposit, meansfor forming a blast of air longitudinally of the tube, a handle and means uniting said handle with said jet forming means, said burner and said air blast means. Y

12. Apparatus for removing combustible deposits from the interior of tubes comprising means provided with orifices for forming a plurality of jets of oxygen so arranged that the jets impinge c upon the deposit to be removed with a swirling motion, means for directing a blast of air longitudinally of the tube, at least one burner means for heating the deposit and means including a water cooling jacket surrounding said jet forming means. n

13. In an apparatus for removing combustible deposits from tubes, the combination of a base, oxygen-distributing means on said base, a plurality of oxygen tips, injector means connecting said tips with said oxygen distributing means, a jacket surrounding said tips and injector means, and a conduit for supplying a diluting fluid to the interior of said jacket adjacent said injector means. A-

14. Apparatus for removing combustible deposits from the interior of tubes comprising a central tube having apertures in the sides thereof, a plurality of oxygen jet forming means arranged about said central tube, said jet forming means being provided with injectors adjacent the aper tures in said centraltubes, a casing surrounding said jet forming means, means for supplying air to said central tube and means for supplying oxycasing engaging said base and surrounding said injectors and the portionofthe central tube provided with apertures, and at least one burner having its end adjacent the ends of the oxygen tips and means for supplying fuel to said burner.`

CHARLES E. RHEIN. JAMES J. BRUTON.

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