US3472907A - Method of operating regenerative furnaces and apparatus therefor - Google Patents

Method of operating regenerative furnaces and apparatus therefor Download PDF

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Publication number
US3472907A
US3472907A US484027A US3472907DA US3472907A US 3472907 A US3472907 A US 3472907A US 484027 A US484027 A US 484027A US 3472907D A US3472907D A US 3472907DA US 3472907 A US3472907 A US 3472907A
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furnace
masses
heat
burn
gas
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Clarence J Coberly
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Union Carbide Corp
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Union Carbide Corp
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Assigned to MORGAN GUARANTY TRUST COMPANY OF NEW YORK, AND MORGAN BANK ( DELAWARE ) AS COLLATERAL ( AGENTS ) SEE RECORD FOR THE REMAINING ASSIGNEES. reassignment MORGAN GUARANTY TRUST COMPANY OF NEW YORK, AND MORGAN BANK ( DELAWARE ) AS COLLATERAL ( AGENTS ) SEE RECORD FOR THE REMAINING ASSIGNEES. MORTGAGE (SEE DOCUMENT FOR DETAILS). Assignors: STP CORPORATION, A CORP. OF DE.,, UNION CARBIDE AGRICULTURAL PRODUCTS CO., INC., A CORP. OF PA.,, UNION CARBIDE CORPORATION, A CORP.,, UNION CARBIDE EUROPE S.A., A SWISS CORP.
Assigned to UNION CARBIDE CORPORATION, reassignment UNION CARBIDE CORPORATION, RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: MORGAN BANK (DELAWARE) AS COLLATERAL AGENT
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S585/00—Chemistry of hydrocarbon compounds
    • Y10S585/949—Miscellaneous considerations
    • Y10S585/95—Prevention or removal of corrosion or solid deposits

Definitions

  • the regenerative furnace of this invention is generally "United States Patent O similar to that shown and described in lPatent No.
  • the furnace is at operating temperature atthe start of the bum-out cycle it is not necessary to add fuel as the heat stored in the ceramic in the center section of the furnace is sufficient and the air ow will carry the heat to the end of the furnace.
  • the furnace has previously been operating under temperature conditions normal for the production of acetylene and/ or ethylene, it requires about 20 minutes for the heat to carry out to one end of the furnace to ignite the deposit at that end and about l0 minutes more to burn it out, and a similar 20 minute period of a reversed heating cycle to carry the heat out to the other end of the furnace and another 10 minutes to burn out the deposit at that end.
  • Allowing a reasonable period to insure complete bum-out of each of the two deposits in a furnace it requires about one hour for each furnace for such burn-out operation. Since such furnaces are usually operated in pairs, as generally illustrated and described in my Patent No. 2,956,864, the foregoing means that it requires about two hours to so clean up an installation. During such time, the production of acetylene and/or ethylene must be discontinued, which disrupts Vplant operation and adds to production costs. It has been normal practice in a commercial plant to perform such burn-out operation on a routine rbasis of approximately once a week.
  • a primary object of this invention is to provide an improved regenerative furnace and method of operating the same to avoid or minimize the disadvantages referred to above which have been usual in the operation of conventional regenerative furnaces in the manufacture of acetylene and/or ethylene. Stated generally, this is accomplished by periodically introducing a free flame into each outer end of the furnace, preferably at the beginning of a heating cycle, allowing it to continue to burn n' for a small fraction of the heating cycle and for a suffi- 4matically in each outer end of the furnace, without interrupting the normal operation of the furnace.
  • Another object of the invention is to form such free flame ⁇ by diverting at least a portion of the ffuel gas, normally used in the heating cycle, alternately to the outer ends of the furnace, where it is mixed with the air normally passed into the furnace during such heating cycle to form a flammable mixture, and igniting such mixture before it passes into the outer end of the checkers of the furnace.
  • Still another object of the invention is to operate such a furnace so as to form such a tar deposit deliberately during each cracking cycle of the furnace and then to burn out such deposit on a subsequent heating cycle to utilize such burn-out as an additional source of heat during the heating cycle.
  • FIG. 1 in diagrammatic form, partly in section, shows the furnace of my invention and the piping and some of the auxiliary apparatus thereof;
  • FIGS. 2, 3, and 4 are diagrams illustrating certain of the steps in the practice of the method of the invention.
  • FIG. 5 is an enlarged, fragmentary, sectional view showing an igniting device of the invention.
  • FIG. l shows a furnace 10, having a steel shell 11 provided with a ⁇ heat insulating lining 12. Inside the lining 12 are three spaced regenerative masses of checkers 13, 14, and 15, providing a combustion space 16 between the masses 14 and 15 and a combustion space 17 between the masses 13 and 14.
  • the regenerative masses 15 and 13, for convenience of description, are hereinafter referred to as the left-hand (LH) and right-hand (RH) end masses, respectively, and the regenerative mass 14 as the central mass.
  • the RH mass 13 is provided with a plurality of passages 19 which extend longitudinally therethrough (shown in endview in FIG. 5), and the masses 14 and 15 have similar passages therethrough.
  • the right-hand and left-hand ends of the furnace are provided with plenum chambers 20 and 21 respectively.
  • a fuel supply pipe 23 supplies fuel gas through a main valve 24 to a manifold 25 provided with a pair of threeway valves 26 and 27.
  • the valve 26 has connected thereto a gas supply pipe 28 which leads to a plurality of vertically spaced nozzles 29 which extend into the combustion space 17 to supply fuel gas thereto.
  • the valve 27 has connected thereto a gas supply pipe 30 which leads to a plurality of vertically spaced nozzles 31 which extend into the combustion space 16 to supply fuel gas thereto.
  • the supply pipes 28 and 30 are each in the form of a yoke straddling the furnace and each is provided with a set of such nozzles on each side of the furnace 10, it being understood that the supply pipe 28 has a second set of nozzles similar to the nozzles 31, on the near side of the furnace, and the supply pipe 30 has a second set of nozzles similar to the nozzles 29 on the far side of the furnace. Although for convenience only three such nozzles have been shown in each bank thereof, it is to be understood that conventionally additional vertically spaced nozzles are usually provided in each bank thereof.
  • the three-way valve 26 also has connected thereto a secondary gas supply pipe 33 which leads to a manifold 34 communicating with the RH plenum chamber 20.
  • the three-way valve 27 has connected thereto a secondary gas supply pipe 35 which leads to a manifold 36 communicating with the LH plenum chamber 21.
  • an air supply pipe 37 communicating with a source of air (not shown), and having valves 38 and 39 therein; an
  • a suitable hydrocarbon feed such as, for example, propane
  • the igniter 57 includes a nipple 59 connected to the manifold 34 and into which is fitted an electric sparking device 60, supplied with a high potential electric current, such as 5000 to 10,000 volts, by an electric cable 61.
  • the sparking device 60 includes a metal collar 62 threaded into the nipple 59 and onto which tits a tubular collar 63, the outer end of which is threaded to receive a coupling 64 in which is mounted an insulator which houses the end of the cable 61 and the end of an ignition rod 66 electrically connected to the end of the cable and extending into the manifold 34.
  • the collar 62 has a tubular extension 67 which surrounds the rod 66, the outer end being provided with perforations 63 to admit gas thereinto between the extension and the rod.
  • the three-way valves 26 and 27 are conventional solenoid-operated valves and are controlled by a conventional timer (not shown). Each of such valves may be closed to shut off any tiow of fuel gas therethrough, actuated to pass the full flow of fuel gas from the fuel supply pipe 23 to one of the combustion chambers 16 or 17, actuated to pass the full ow of fuel gas from the supply pipe 23 to one of the manifolds 34 or 36, or actuated to divide the flow of fuel gas between the plenum chamber 20 and the combustion chamber 17, or between the plenum chamber 21 and the combustion chamber' 16.
  • the regenerative masses are first heated up to operating temperatures by a preheating step, as generally described in my Patent No. 2,967,205.
  • a preheating step for the production of acetylene the central mass 14 is heated to a temperature of about 2200 F. and the end masses 13 and 1S are heated to a temperature somewhat lower than 2200 F. adjacent to the combustion spaces 16 and 17 and to a much lower temperature, e.g., below 400 C. at their outer ends, with a fairly uniform temperature drop profile between the inner and outer end of each of the end masses.
  • the valving is adjusted to provide the connections illustrated in FIG. 4, in which valves 46, 50, 53, and 55 are opened and all other valves are closed.
  • the hydrocarbon feed stock such as propane, ows into the mixer 51 from the pipe 54, where it is mixed with a diluent, such as steam, from the pipe 52, to form the usual in-gas.
  • the ingas then ows through the pipe 48 and the manifold 36 into the left-hand (LH) plenum chamber 21 from which bustion space 16, the central mass 14, the combustion space 17, and the RH mass 13, cracking taking place largely in the central mass 14, to form an off-gas containing the desired end product, e.g., acetylene and/or ethylene.
  • the off-gas is quenched to a much lower temperature during its passage through the cooler RH end mass 13, and passes through the plenum chamber 20 into the manifold 34 and thence through the off-gas pipe 45 to storage or use.
  • RH right-hand
  • valves 26, 38, and 44 are opened and all other valves are closed. Air is conveyed through the air supply pipe 37 and the manifold 34 into the RH plenum chamber 20 and thence through the RH mass 13, cooling the same, and into the RH combustion chamber 17 where it mixes with fuel gas supplied thereto through thefuel supply pipe 28 and nozzles 29, to form a combustible mixture which automatically ignites and burns, the hot products of combustion passing therefrom through the central mass, from right to left, to heat it back up to cracking temperatures, and then through the LH combustion chamber 116, the LH regenerative mass 15, the LH plenum chamber 21, the manifold 36, and the exhaust pipe 41 to the stack 42 from which such products of combustion are discharged.
  • Such a LH heat step is conventional.
  • the valving is readjusted to pass air into the LH end of the furnace, through the LH mass 15 and into the LH combustion chamber 16 where it mixes with fuel gas introduced thereinto through the nozzles 31, ignites to form products of combustion which then pass left to right through the balance of the furnace and the manifold 34 to the stack 42, to reestablish the heat balance following a RH make step.
  • the novel features of the method of my invention relate to the conventional heat steps previously described.
  • the valving is set as illustrated in FIG. 2, in which the valves 38 and 44 are opened and the three-way valve 26 is adjusted to direct all fuel gas from the fuel supply line 23 through the supply pipe 33 to the manifold 34, so that such fuel gas mixes in the manifold with air therein, adjacent to the RH plenum chamber to form a flammable or combustible mixture.
  • the electrical impulse delivered through the cable 61 need only be momentary, as the spark therefrom immediately ignites the combustible mixture, which continues to burn, and the electrical impulse is then discontinued by suitable switching (not shown).
  • a suitable timer (not shown) may be provided to synchronize automatically the opening of the valves 26, 38, and 44 with the supply of high voltage to igniter 57, and this is a further feature of the invention.
  • a conventional heating step as generally illustrated in FIG. 3 and described above, requires about one minute.
  • the valving is reset as shown in FIG. 3 and the regular heating step then continues until the end of its normal period of time.
  • the carbon and tar deposits in the passages 19 continue to burn during the regular heating step, since air continues to flow' through such passages during the regular heating step, to eliminate such deposits, which is a further ,feature and advantage of my method.
  • Such burn-out step is in fact a part of the main heating step, as the burning of the combustible mixture and the hot products of combustion therefrom transfers sensible heat to the walls of the passages 19 of the masses 13, 14, and 15 and serves to heat the same.
  • the burning of the carbon and tar deposits, as described above furnishes additional heat, such carbon and tar deposits serving as fuel therefor, and this is a further feature and advantage of the invention in that it improves the overall heat eciency of the operation.
  • the burn-out step and heating step may be combined, without departing from the spirit of the invention.
  • the valving is as illustrated in FIG. 2, but the three-way valve 26 is adjusted to divide the supply of fuel gas between the pipes 28 and 33, so that a portion of the fuel gas passes to the plenum chamber 20, is there mixed with air and ignited as previously described to provide the burn-out feature, while at the same time the balance of the fuel gas supply is passed directly into the RH combustion space 17 through the pipe 28, where it mixes with the excess air from the plenum chamber 20 and the mixture ignites to provide the normal heating step previously described.
  • the three-way valve 26 is readjusted to shut off the iiow of fuel gas to the plenum chamber 20 through the supply pipe 33 and convey all of the fuel gas supply directly into the combustion space 17 through the pipe 28, after which the heat step continues normally as described above.
  • RH make step is followed by a similar, but reversed, RH heat step, in which the valving is reversed to put air in the lefthand end of the furnace, and fuel gas'in the left-hand plenum chamber 21 for the burn-out of the left-hand end of the furnace and fuel in the LH combustion space 16 for the normal RH heat step.
  • the burn-out step may be effected at the beginning of each heat step, and this is frequently desirable if the feed stock and operating conditions deposit any substantial carbon or tar during the normal make steps, if such deposit is light during any single make step, due to less stringent operating conditions, it is unnecessary to provide such burn-out step at the beginning of every heat step. Consequently, when conditions permit, my method is practiced by using the burn-out step at the beginning of a heat step, in each direction, only periodically during normal operation. I have found that under some favorable conditions of operation of the furnace, although the heat and make steps may be alternated with periods of one minute each, for example, the burn-out step need only be effected every l or 15 minutes, or even less frequently, to maintain the furnace adequately clean of carbon and tar deposits.
  • An alternative embodiment of the invention is to add a differential pressure switch (not shown) which measures the pressure drop across the furnace from one plenum chamber to the other and which closes a control circuit any time this pressure differential becomes too great to bring the burn-out function into operation. This may either cut off as soon as the differential has been brought down or run for a predetermined period of time each time the differential reaches a point too high.
  • the furnace can be kept adequately clean of carbon and tars at all times, with the result that the pressure drop through the passages 19 of the ceramic checkers remains substantially uniform and maintains the yield of cracked gas from the make steps at a maximum. This is done automatically and requires no manual control or attention during operation. The result is an improved efficiency of operation and also a reduction of nonproductive downtime and maintenance labor.
  • a method of operating a regenerative furnace having at least three regenerative masses including two end masses and a central mass therebetween, said masses being spaced apart, each of the masses having a plurality of longitudinal passages therethrough, which includes alternating heat and make steps in each direction through the furnace, the make steps depositing undesirable foreign materials on the walls of the outer portions of the passages of the end masses, each heat step including passing an air stream through one of the outer masses from the outer end thereof towards the others of said masses and into the space between said one of said outer masses and said central mass Where it is mixed with a fuel gas to form a first combustible mixture which ignites and the products of combustion pass through the central mass and the other of said end masses, characterized by:
  • a method of operating a regenerative furnace having at least three regenerative masses including two end masses and a central mass therebetween, said masses being spaced apart, each of the masses having a plurality of longitudinal passages therethrough, which includes alternating heat and make steps in each direction through the furnace, the make steps depositing undesirable foreign materials on the walls of the outer portions of the passages of the end masses, each heat step including passing an air stream through one of the outer masses from the outer end thereof toward the others of said masses and into the space between said one of said outer masses and said central mass where it is mixed with a fuel gas to form a first combustible mixture which ignites and the products of combustion pass through the central mass and the other of said end masses, characterized by: at the beginning of a heat step, diverting at least a portion of said fuel gas to an end of the furnace and there mixing such portion with the air to form a second combustible mixture;
  • a regenerative furnace having first and second end regenerative masses and a central regenerative mass therebetween, such masses being spaced apart to provide a first combustion space between said first and central masses and a second combustion space between said second and central masses, each of said masses having a plurality of longitudinal passages therethrough, the combination of:
  • a plenum chamber at each end of the furnace, each communicating with an outer end of one of said end masses;
  • a regenerative furnace having first and second end regenerative masses and a central regenerative mass therebetween, such masses being spaced apart to provide a first combustion space between -said first and central masses and a second combustion space between said second and central masses, each of said masses having a plurality of longitudinal passages therethrough, the combination of:
  • a plenum chamber at each end of the furnace, each communicating with an outer end of one of said end masses;
  • timing means for automatically and periodically causing fuel gas and air to flow into each of said plenum chambers to form a combustible mixture and operating said igniting means to ignite said mixture.
  • Y 1D 260-683 means for conveying a fuel gas to said combustion space means

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Thermal Sciences (AREA)
  • Organic Chemistry (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Incineration Of Waste (AREA)
  • Air Supply (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Furnace Details (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US484027A 1965-08-31 1965-08-31 Method of operating regenerative furnaces and apparatus therefor Expired - Lifetime US3472907A (en)

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US (1) US3472907A (sh)
JP (1) JPS4920473B1 (sh)
BE (1) BE686233A (sh)
DK (1) DK138083B (sh)
ES (2) ES330647A1 (sh)
GB (1) GB1129568A (sh)
IL (1) IL26384A (sh)
NL (1) NL150505B (sh)
SE (1) SE331835B (sh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888302A (en) * 1973-10-01 1975-06-10 Kaiser Steel Corp Method for removing deposits from interior surfaces of regenerative heat exchangers
US4061544A (en) * 1976-05-03 1977-12-06 Koppers Company, Inc. Apparatus for providing waste gas recirculation in coke oven batteries

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2785212A (en) * 1954-11-29 1957-03-12 Phillips Petroleum Co Regenerative furnace and production of unsaturated hydrocarbons therein
CA538572A (en) * 1957-03-26 L. Hasche Rudolph Pyrolytic process for endothermically altering a gaseous material
US3093697A (en) * 1960-05-27 1963-06-11 Union Carbide Corp Process for producing acetylene

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA538572A (en) * 1957-03-26 L. Hasche Rudolph Pyrolytic process for endothermically altering a gaseous material
US2785212A (en) * 1954-11-29 1957-03-12 Phillips Petroleum Co Regenerative furnace and production of unsaturated hydrocarbons therein
US3093697A (en) * 1960-05-27 1963-06-11 Union Carbide Corp Process for producing acetylene

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888302A (en) * 1973-10-01 1975-06-10 Kaiser Steel Corp Method for removing deposits from interior surfaces of regenerative heat exchangers
US4061544A (en) * 1976-05-03 1977-12-06 Koppers Company, Inc. Apparatus for providing waste gas recirculation in coke oven batteries

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DK138083B (da) 1978-07-10
DE1593654B2 (de) 1975-07-17
SE331835B (sh) 1971-01-18
ES330647A1 (es) 1967-09-16
DK138083C (sh) 1978-11-27
ES341108A1 (es) 1968-07-16
BE686233A (sh) 1967-02-28
NL6612137A (sh) 1967-03-01
JPS4920473B1 (sh) 1974-05-24
DE1593654A1 (de) 1972-04-13
NL150505B (nl) 1976-08-16
GB1129568A (en) 1968-10-09
IL26384A (en) 1970-09-17

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