HRP20050072A2 - Method and ribbed tube for thermally cleaving hydrocarbons - Google Patents
Method and ribbed tube for thermally cleaving hydrocarbons Download PDFInfo
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- HRP20050072A2 HRP20050072A2 HR20050072A HRP20050072A HRP20050072A2 HR P20050072 A2 HRP20050072 A2 HR P20050072A2 HR 20050072 A HR20050072 A HR 20050072A HR P20050072 A HRP20050072 A HR P20050072A HR P20050072 A2 HRP20050072 A2 HR P20050072A2
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 229930195733 hydrocarbon Natural products 0.000 title claims description 7
- 150000002430 hydrocarbons Chemical class 0.000 title claims description 7
- 230000008569 process Effects 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 8
- 238000012360 testing method Methods 0.000 claims description 7
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 239000011651 chromium Substances 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 6
- 238000012546 transfer Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 239000010955 niobium Substances 0.000 claims description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 238000004227 thermal cracking Methods 0.000 claims description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 239000010937 tungsten Substances 0.000 claims description 3
- 238000003466 welding Methods 0.000 claims description 3
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 2
- 229910052735 hafnium Inorganic materials 0.000 claims description 2
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims 1
- 239000000956 alloy Substances 0.000 claims 1
- -1 rare earths Chemical compound 0.000 claims 1
- 239000007789 gas Substances 0.000 abstract description 12
- 230000009471 action Effects 0.000 abstract description 2
- 239000010779 crude oil Substances 0.000 abstract description 2
- 230000000630 rising effect Effects 0.000 abstract 1
- 238000000926 separation method Methods 0.000 abstract 1
- 238000005336 cracking Methods 0.000 description 13
- 239000000571 coke Substances 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 239000010410 layer Substances 0.000 description 8
- 238000000197 pyrolysis Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000001133 acceleration Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000004939 coking Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005482 strain hardening Methods 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000003421 catalytic decomposition reaction Methods 0.000 description 1
- 238000002144 chemical decomposition reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010622 cold drawing Methods 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
-
- 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
- C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
- C10G9/18—Apparatus
- C10G9/20—Tube furnaces
-
- 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
- C10G9/24—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils by heating with electrical means
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/40—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only inside the tubular element
-
- 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
- C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
- C10G2300/80—Additives
- C10G2300/805—Water
- C10G2300/807—Steam
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Metallurgy (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
Izum se odnosi na proces i rebrastu cijev za termičko krekiranje ugljikovodika u prisutnosti pare, u kojem smjesa punjenja prolazi kroz izvana zagrijavane cijevi s unutarnjim spiralnim rebrima. The invention relates to a process and a finned tube for the thermal cracking of hydrocarbons in the presence of steam, in which the charge mixture passes through externally heated tubes with internal helical fins.
Cijevne peći, u kojima smjesa ugljikovodika i pare prolazi kroz niz pojedinih ili meandrirajućih cijevi (cracking tube coils) pri temperaturama iznad 7500C, izrađenih od toplinski otpornih krom-nikal-čelik legura s velikom otpornošću na oksidaciju ili ljuštenje kamenca i visokom otpornošću na karburizaciju, su dokazano prikladne za visokotemperaturnu pirolizu ugljikovodika (derivata sirove nafte). Cijevni snopovi sadrže vertikalno protežuće, ravne cijevne sekcije koje su spojene jedna na drugu preko U-oblikovanih cijevnih koljena ili su raspoređene paralelno jedna prema drugoj; one se obično zagrijavaju uz pomoć bočnih plamenika i u nekim slučajevima također uz pomoć donjih plamenika i zbog toga imaju, kako je poznato, svijetlu stranu, koja gleda prema plamenicima i što je poznato, tamnu stranu, koja je suprotna za 900 s obzirom na nju, tj. proteže se u smjeru redova cijevi. Srednje temperature metala cijevi (Tube Metal Temperatures, TMT) su u nekim slučajevima preko 10000C. Tube furnaces, in which a mixture of hydrocarbons and steam passes through a series of individual or meandering tubes (cracking tube coils) at temperatures above 7500C, made of heat-resistant chromium-nickel-steel alloys with high resistance to oxidation or scaling and high resistance to carburization, are proven suitable for high-temperature pyrolysis of hydrocarbons (crude oil derivatives). Pipe bundles contain vertically extending, straight pipe sections that are connected to each other via U-shaped pipe elbows or are arranged parallel to each other; they are usually heated with the help of the side burners and in some cases also with the help of the bottom burners and therefore have, as is known, a light side, which faces the burners and, as is known, a dark side, which is the opposite for the 900 with respect to it, i.e. it extends in the direction of the pipe rows. Tube Metal Temperatures (TMT) are in some cases over 10000C.
Radni vijek cijevi za kreking je zavisan o vrlo značajnom opsegu otpornosti na puzanje i otpornosti na karburizaciju i također o brzini stvaranja koksa od materijala cijevi. Krucijalni faktor za brzinu stvaranja koksa, tj. rasta sloja ugljikovog depozita (piroliznog koksa) na unutarnjoj stijenci cijevi jest, uz tip korištenih ugljikovodika, temperatura plina krekiranja u području unutarnje stijenke i ono što je poznato kao žestina u radu, koja prikriva utjecaj sistemskog tlaka i vremena zadržavanja u cijevnom sistemu na iskorištenje etilena. Žestina u radu se podešava na bazi srednje izlazne temperature plinova krekinga (npr. 850ºC). Što je viša temperatura plina u blizini unutarnje stijenke cijevi iznad ove temperature, to postaje jači rast sloja piroliznog koksa, a izolirajuće djelovanje ovog sloja omogućuje da se temperatura metala cijevi još dalje povećava. Premda krom-nikal-čelik legure, koje sadrže 0,4% ugljika, preko 25% kroma i preko 20% nikla, na primjer 35% kroma, 45% nikla i ako je prikladno 1% niobija, a koje se koriste kao materijal za cijevi imaju visoku otpornost na karburizaciju, ugljik difundira u stijenku cijevi kod defekata u oksidnom sloju, gdje on dovodi do značajne karburizacije koja može iznositi do sadržaja ugljika od 1% do 3% pri debljinama stijenki od 0,5 do 3 mm. Ovo je povezano sa značajnim povećanjem krtosti materijala cijevi, uz rizik formiranja pukotina u slučaju fluktuirajućih termičkih opterećenja, osobito kada se peć pali ili zaustavlja. The service life of a cracking tube depends on a very significant extent of creep resistance and carburization resistance and also on the rate of coke formation of the tube material. The crucial factor for the rate of coke formation, i.e. the growth of the layer of carbon deposit (pyrolysis coke) on the inner wall of the pipe, is, in addition to the type of hydrocarbons used, the temperature of the cracking gas in the area of the inner wall and what is known as the intensity of operation, which hides the influence of the system pressure and retention time in the pipe system for the utilization of ethylene. The intensity of the operation is adjusted based on the mean outlet temperature of the cracking gases (eg 850ºC). The higher the temperature of the gas near the inner wall of the tube above this temperature, the stronger the growth of the pyrolysis coke layer becomes, and the insulating effect of this layer allows the temperature of the metal of the tube to increase even further. Although chromium-nickel-steel alloys, containing 0.4% carbon, over 25% chromium and over 20% nickel, for example 35% chromium, 45% nickel and if appropriate 1% niobium, which are used as material for pipes have a high resistance to carburization, carbon diffuses into the pipe wall at defects in the oxide layer, where it leads to significant carburization that can amount to a carbon content of 1% to 3% at wall thicknesses of 0.5 to 3 mm. This is associated with a significant increase in the brittleness of the pipe material, with the risk of cracking in case of fluctuating thermal loads, especially when the furnace is turned on or stopped.
Da bi se prekinulo odlaganje ugljika (coking) na unutarnjoj stijenci cijevi, potrebno je s vremena na vrijeme prekinuti rad na krekiranju, da pirolizni koks izgori uz pomoć smjese pare i zraka. Ovo traži da se rad prekine do 36 sati, i zbog toga ima značajno nepovoljan učinak na ekonomičnost procesa. In order to stop the deposition of carbon (coking) on the inner wall of the pipe, it is necessary to stop the cracking work from time to time, so that the pyrolysis coke burns with the help of a mixture of steam and air. This requires work to be stopped for up to 36 hours, and therefore has a significant adverse effect on the economics of the process.
Iz Britanskog patenta 969 796 također je poznata uporaba cijevi za krekiranje s unutarnjim rebrima. Iako unutarnja rebra ovog tipa rezultiraju površinom unutarnje plohe, koja je za dobrih nekoliko postotaka, na primjer za 10% veća, uz odgovarajuće poboljšanje prijenosa topline, ona su također povezana s nedostatkom značajno povećanog gubitka tlaka u usporedbi s glatkom cijevi, na račun trenja o povećanu unutarnju plohu cijevi. Viši gubitak tlaka zahtijeva viši sistemski tlak, koji neizbježno mijenja vrijeme zadržavanja i ima nepovoljan učinak na iskorištenje. Dodatni je faktor, da se poznati materijali za cijevi s visokim sadržajem ugljika i kroma više ne mogu profilirati hladnom obradom, na primjer hladnim vučenjem. Oni imaju nedostatak da njihova deformabilnost uvelike pada, kako raste čvrstoća pri zagrijavanju. Ovo je dovelo do visokih temperatura metala do na primjer 1050ºC, koje su poželjne s obzirom na iskorištenje etilena, što traži uporabu centrifugirano lijevanih cijevi. Međutim, budući da se centrifugirano lijevane cijevi mogu proizvoditi samo s cilindričnom stijenkom, traže se specijalni procesi za oblikovanje, na primjer odstranjivanje materijala pomoću elektrolitičke strojne obrade, procesa oblikovanja zavarivanjem, ako se treba proizvesti iznutra orebrene cijevi. British Patent 969 796 also discloses the use of a cracking tube with internal fins. Although internal fins of this type result in an internal surface area that is a good few percent, for example 10% larger, with a corresponding improvement in heat transfer, they are also associated with the lack of significantly increased pressure loss compared to a smooth tube, at the expense of friction o increased internal pipe surface. A higher pressure loss requires a higher system pressure, which inevitably changes the residence time and has an unfavorable effect on the utilization. An additional factor is that known tube materials with high carbon and chromium content can no longer be profiled by cold working, for example cold drawing. They have the disadvantage that their deformability drops greatly as the strength increases upon heating. This led to high metal temperatures up to, for example, 1050ºC, which are desirable in view of the utilization of ethylene, which requires the use of centrifugally cast pipes. However, since centrifugally cast pipes can only be produced with a cylindrical wall, special forming processes are required, for example material removal by electrolytic machining, welding forming processes, if internally ribbed pipes are to be produced.
S obzirom na ovo stanje tehnike, izum je baziran na problemu poboljšanja ekonomičnosti termičkog krekiranja ugljikovodika u cijevnim pećima s izvana zagrijavanim cijevima koje imaju spiralna unutarnja rebra. In view of this state of the art, the invention is based on the problem of improving the economics of thermal cracking of hydrocarbons in tube furnaces with externally heated tubes having spiral internal fins.
Ovaj se cilj postiže procesom u kojem vrtložno strujanje nastaje u neposrednoj blizini rebra, pogodno centrifugirano lijevane cijevi i ovo se vrtložno strujanje pretvara u zoni jezgre u pretežno aksijalno strujanje, kako raste radijalna udaljenost od rebara. Prijelaz između vanjske zone s vrtložnim strujanjem i zone jezgre s pretežno aksijalnim strujanjem je postepen, na primjer paraboličan. This goal is achieved by a process in which the eddy current is created in the immediate vicinity of the rib, preferably of a centrifugally cast tube, and this eddy current is converted in the core zone to a predominantly axial flow, as the radial distance from the ribs increases. The transition between the outer zone with eddy flow and the core zone with predominantly axial flow is gradual, for example parabolic.
U postupku u skladu s izumom, vrtložno strujanje poprima odvajajuće vrtloženje na bokovima rebra, tako da se vrtloženje lokalno ne reciklira u obliku kontinuiranog cirkulirajućeg strujanja u dolinama rebara. Usprkos očito duljim udaljenostima koje čestice moraju nadoknaditi u spiralnim putanjama, srednje vrijeme zadržavanja je niže nego u glatkoj cijevi i štoviše, homogenije preko poprečnog presjeka (usporedi sa Sl. 7). Ovo je potvrđeno višom cjelokupnom brzinom u profiliranoj cijevi s vrtlogom (profil 3) u usporedbi s cijevi s ravnim rebrima (profil 2). Ovo je osobito osigurano, ako je vrtložno strujanje u području rebara ili ako rebra teku pod kutem od 200 do 400, na primjer 300, pogodno 25 do 32,50, s obzirom na os cijevi. In the process according to the invention, the eddy flow acquires a separating vorticity at the rib flanks, so that the vorticity is not locally recycled in the form of a continuous circulating flow in the rib valleys. Despite the apparently longer distances that the particles have to cover in spiral trajectories, the mean residence time is lower than in a smooth tube and, moreover, more homogeneous across the cross-section (compare with Fig. 7). This is confirmed by the higher overall velocity in the profiled vortex tube (profile 3) compared to the straight finned tube (profile 2). This is particularly ensured if there is a vortex flow in the region of the ribs or if the ribs run at an angle of 200 to 400, for example 300, preferably 25 to 32.50, with respect to the pipe axis.
U procesu u skladu s izumom, dobava topline, koja se neizbježno razlikuje preko oboda cijevi između svijetle strane i tamne strane, se kompenzira u stijenci cijevi i unutrašnjosti cijevi i toplina se brzo širi prema unutra u zonu jezgre. Ovo je povezano sa smanjenjem rizika lokalnog pregrijavanja procesnog plina kod stijenke cijevi, uz posljedicu formiranja piroliznog koksa. Štoviše, toplinsko opterećenje na materijal cijevi je niže na račun temperaturne kompenzacije između svijetle strane i tamne strane, koja produljuje radni vijek uporabe. Konačno, u procesu u skladu s izumom, temperatura se također ujednačava preko poprečnog presjeka cijevi, rezultirajući povećanim iskorištenjem olefina. Razlog tome jest, da bez radijalne temperaturne kompenzacije u skladu s izumom u unutrašnjosti cijevi, pojavilo bi se prekomjerno krekiranje kod vruće stijenke cijevi, a u centru cijevi bi se pojavila rekombinacija produkata krekiranja. In the process according to the invention, the heat supply, which inevitably differs across the tube periphery between the bright side and the dark side, is compensated in the tube wall and inside the tube and the heat rapidly spreads inwards to the core zone. This is related to the reduction of the risk of local overheating of the process gas at the pipe wall, with the consequence of the formation of pyrolysis coke. Moreover, the thermal load on the pipe material is lower due to the temperature compensation between the light side and the dark side, which extends the service life. Finally, in the process according to the invention, the temperature is also uniform across the cross-section of the tube, resulting in increased olefin recovery. The reason for this is that without radial temperature compensation in accordance with the invention in the interior of the pipe, excessive cracking would occur at the hot wall of the pipe, and recombination of cracking products would occur in the center of the pipe.
Nadalje, sloj laminarnog strujanja, koji je karakteristika turbulentnih strujanja, s uvelike smanjenim prijenosom topline formira se u slučaju glatke cijevi, a do velikog opsega u slučaju rebrastih profila s unutarnjim obodom koji se radi rebara povećava za više od 5%, na primjer 10%. Ovo laminarno strujanje dovodi do povećanog formiranja piroliznog koksa, slično kao i kod slabe toplinske vodljivosti. Dva sloja zajedno traže veće uvođenje topline ili veći kapacitet plamenika. Ovo povećava temperaturu metala cijevi (TMT) i odgovarajuće skraćuje radni vijek. Furthermore, a layer of laminar flow, which is a characteristic of turbulent flows, with a greatly reduced heat transfer is formed in the case of a smooth tube, and to a large extent in the case of ribbed profiles with an inner rim made of ribs, which increases by more than 5%, for example 10% . This laminar flow leads to increased formation of pyrolysis coke, similar to low thermal conductivity. Two layers together require greater heat input or greater burner capacity. This increases the tube metal temperature (TMT) and shortens the service life accordingly.
Izum ovo izbjegava zbog činjenice da unutarnji obod profila iznosi do oko najviše 5%, na primjer 4% ili čak 3,5% s obzirom na obod upisane kružnice koja dodiruje doline rebara. Međutim, unutarnji obod može biti također do 2% manji od upisane kružnice. Drugim riječima, relativni obod profila iznosi najviše 1,05 do 0,98 od oboda upisane kružnice. U skladu s tim, razlika u površini profila cijevi u skladu s izumom, tj. njegove razvijene unutarnje površine plohe, s obzirom na glatku cijev koja ima upisani dijametar kružnice, iznosi do najviše +5% do -2% ili 1,05 do 0,98 puta površine glatke cijevi. The invention avoids this due to the fact that the inner circumference of the profile is up to about 5% at most, for example 4% or even 3.5% with respect to the circumference of the inscribed circle touching the valleys of the ribs. However, the inner circumference can also be up to 2% smaller than the inscribed circle. In other words, the relative circumference of the profile is at most 1.05 to 0.98 of the circumference of the inscribed circle. Accordingly, the difference in the surface area of the pipe profile according to the invention, i.e. its developed internal surface area, with respect to a smooth pipe having an inscribed circle diameter, amounts to a maximum of +5% to -2% or 1.05 to 0 .98 times the area of a smooth tube.
Profil cijevi u skladu s izumom dopušta nižu specifičnu masu cijevi (kg/m) u usporedbi s rebrastom cijevi kod koje je unutarnji obod profila barem 10% veći od oboda upisane kružnice. Ovo se pokazuje usporedbom između dviju cijevi istog hidrauličkog dijametra i u skladu s tim jednakog pada tlaka i istog termičkog rezultata. The pipe profile according to the invention allows a lower specific mass of the pipe (kg/m) compared to a ribbed pipe where the inner circumference of the profile is at least 10% larger than the circumference of the inscribed circle. This is demonstrated by a comparison between two pipes of the same hydraulic diameter and, accordingly, the same pressure drop and the same thermal result.
Daljnja prednost profilnog oboda u skladu s izumom (relativnog profilnog oboda) s obzirom na obod upisane kružnice je mnogo brže zagrijavanje punjenog plina pri smanjenoj temperaturi metala cijevi. A further advantage of the profile rim according to the invention (relative profile rim) with regard to the rim of the inscribed circle is much faster heating of the filled gas at a reduced temperature of the pipe metal.
Vrtložno strujanje u skladu s izumom vrlo značajno smanjuje opseg laminarnog sloja; štoviše, ono je povezano s vektorom brzine usmjerenim prema centru cijevi, koji smanjuje vrijeme zadržavanja radikala krekiranja i/ili produkata krekiranja uz vruću stijenku cijevi, te njihovo kemijsko i katalitičko raspadanje da se oblikuje pirolizni koks. Eddy flow in accordance with the invention very significantly reduces the extent of the laminar layer; moreover, it is associated with a velocity vector directed towards the center of the tube, which reduces the residence time of cracking radicals and/or cracking products against the hot tube wall, and their chemical and catalytic decomposition to form pyrolysis coke.
Uz to, temperaturne razlike između dolina rebara i rebara, koje nisu beznačajne u slučaju interno profiliranih cijevi s visokim rebrima, se kompenziraju vrtložnim strujanjem u skladu s izumom. Ovo produljuje vrijeme između dviju potrebnih radnih operacija odstranjivanja koksa. Bez vrtložnog strujanja u skladu s izumom, nastaje temperaturna razlika između vrhova rebara i baze dolina rebara koja nije beznačajna. Vrijeme zadržavanja produkata krekiranja koji su skloni nastajanju koksa je kraće u slučaju cijevi za krekiranje opremljenih spiralnim unutarnjim rebrima. Ovo je zavisno o prirodi rebara u individulanim okolnostima. In addition, the temperature differences between the valleys of the ribs and the ribs, which are not insignificant in the case of internally profiled pipes with high ribs, are compensated by the vortex flow in accordance with the invention. This increases the time between the two required coking operations. Without the vortex flow in accordance with the invention, a temperature difference between the tops of the ribs and the base of the rib valleys arises, which is not insignificant. The retention time of coke-prone cracking products is shorter in the case of cracking tubes equipped with helical internal fins. This depends on the nature of the ribs in individual circumstances.
U dijagramu: In the diagram:
Gornja krivulja prikazuje: profil 6: nagib 160 The upper curve shows: profile 6: slope 160
Srednja krivulja prikazuje: profil 3: nagib 300 The middle curve shows: profile 3: slope 300
Donja krivulja prikazuje: profil 4: 3 rebra The lower curve shows: profile 4: 3 ribs
s nagibom 300. with a slope of 300.
Krivulje jasno pokazuju da se viša obodna brzina profila 6 s rebrima visine 4,8 mm potroši unutar dolina rebara, dok naprotiv obodna brzina profila u skladu s izumom s visinom rebara od samo 2 mm prodire u jezgru strujanja. Premda je obodna brzina profila 4 sa samo 3 rebra približno toliko velika, to ne daje efekta na bilo kakvo spiralno ubrzanje jezgrenog strujanja. The curves clearly show that the higher peripheral speed of the profile 6 with ribs 4.8 mm high is consumed within the valleys of the ribs, while on the contrary the peripheral speed of the profile according to the invention with a rib height of only 2 mm penetrates into the core of the flow. Although the circumferential velocity of profile 4 with only 3 fins is approximately as high, this does not effect any spiral acceleration of the core flow.
U skladu s krivuljama prikazanim u dijagramu predstavljenom na Slici 2, profil u skladu s izumom izaziva spiralno ubrzanje u dolinama rebara (gornji ogranak krivulje), što pokriva široke površine poprečnog presjeka cijevi i zbog toga je odgovorno za homogeniziranje temperature u cijevi. Niža obodna brzina kod vrhova rebara (donji ogranak krivulje), nadalje osigurava da se ne pojavljuje turbulencija i povratno strujanje. According to the curves shown in the diagram presented in Figure 2, the profile according to the invention causes a spiral acceleration in the valleys of the ribs (the upper branch of the curve), which covers wide cross-sectional areas of the tube and is therefore responsible for homogenizing the temperature in the tube. The lower peripheral speed at the tips of the fins (the lower branch of the curve) further ensures that turbulence and backflow do not occur.
Slika 3 ilustrira tri probne cijevi, uključujući njihove podatke, u poprečnom presjeku; ove cijevi uključuju profil 3 u skladu s izumom. Svaki dijagram označava temperaturni profil preko radijusa cijevi na tamnoj strani i na svijetloj strani. Usporedba dijagrama otkriva nižu temperaturnu razliku između stijenke cijevi i centra cijevi i nižu temperaturu plina kod stijenke cijevi u slučaju profila 3 u skladu s izumom. Figure 3 illustrates three test tubes, including their data, in cross-section; these pipes include profile 3 according to the invention. Each plot indicates the temperature profile across the tube radius on the dark side and on the bright side. A comparison of the diagrams reveals a lower temperature difference between the pipe wall and the pipe center and a lower gas temperature at the pipe wall in the case of profile 3 according to the invention.
Vrtložno strujanje u skladu s izumom osigurava da je temperaturna fluktuacija unutar stijenke preko oboda cijevi, tj. između svijetle strane i tamne strane, manja od 120C, čak iako se svežnjevi cijevi, koji su uobičajeno raspoređeni u paralelnim redovima u cijevnoj peći zagrijavaju i djeluju pomoću plinova izgaranja uz pomoć postranih plamenika uz stijenku samo na suprotnim stranama i zbog toga svaka cijev ima svijetlu stranu koja gleda prema plamenicima i tamnu stranu koja je izmaknuta za 900 s obzirom na njih. Srednja temperatura metala cijevi, tj. razlika u temperaturi metala cijevi na svijetloj strani i tamnoj strani, dovodi do internih naprezanja i zbog toga određuje radni vijek cijevi. Zbog toga, smanjivanje srednje temperature metala cijevi kod cijevi prema izumu s osam rebara uz nagib od 300, unutarnjim dijametrom od 38,8 mm i vanjskim dijametrom cijevi od 50,8 mm, tj. razlikom visine između dolina rebara i vrhova rebara od 2 mm od 110 u usporedbi s glatkom cijevi istog dijametra, bazirano na srednjem radnom vijeku od 5 godina, što se može vidjeti iz predstavljenog dijagrama na Slici 4, pri radnoj temperaturi od 10500C, rezultira kalkuliranim povećanjem radnog vijeka do približno 8 godina. Eddy current in accordance with the invention ensures that the temperature fluctuation inside the wall across the tube circumference, i.e. between the light side and the dark side, is less than 120C, even though the bundles of tubes, which are usually arranged in parallel rows in the tube furnace, are heated and act by combustion gases by means of side burners against the wall only on opposite sides and therefore each tube has a light side facing the burners and a dark side offset by 900 with respect to them. The mean temperature of the pipe metal, i.e. the difference in the temperature of the pipe metal on the light side and the dark side, leads to internal stresses and therefore determines the service life of the pipe. Therefore, the reduction of the mean temperature of the pipe metal in the pipe according to the invention with eight ribs with a pitch of 300, an inner diameter of 38.8 mm and an outer diameter of the pipe of 50.8 mm, i.e. a difference in height between the valleys of the ribs and the tops of the ribs of 2 mm of 110 compared to a smooth pipe of the same diameter, based on an average service life of 5 years, which can be seen from the diagram presented in Figure 4, at an operating temperature of 10500C, results in a calculated increase in service life of approximately 8 years.
Temperaturna raspodjela između svijetle strane i tamne strane za tri profila prikazana na Slici 3 se treba pronaći na dijagramu prikazanom na Slici 5. Mogu se primijetiti niža razina temperaturne krivulje za profil 3 u usporedbi s glatkom cijevi (profil 0) i značajno uži raspon fluktuacije za krivulju profila 3 u usporedbi s krivuljom profila 1. The temperature distribution between the bright side and the dark side for the three profiles shown in Figure 3 should be found in the diagram shown in Figure 5. One can notice the lower level of the temperature curve for profile 3 compared to the smooth pipe (profile 0) and a significantly narrower fluctuation range for the curve of profile 3 compared to the curve of profile 1.
Posebno svrsishodna raspodjela temperatura se ustanovljava ako izoterme teku u spiralnom obliku od unutarnje stijenke cijevi do jezgre strujanja. A particularly useful temperature distribution is established if the isotherms flow in a spiral form from the inner wall of the pipe to the core of the flow.
Ujednačenija raspodjela temperatura preko poprečnog presjeka rezultira osobito, ako se obodna brzina pojača unutar 2 do 3 m, a zatim ostaje konstantnom duž cijele duljine cijevi. A more uniform distribution of temperatures across the cross-section results especially if the circumferential velocity increases within 2 to 3 m and then remains constant along the entire length of the pipe.
U cilju postizanja visokog iskorištenja olefina uz relativno kratku duljinu cijevi, proces u skladu s izumom bi se trebao izvoditi na takav način, da je faktor temperaturne homogenosti preko poprečnog presjeka i faktor temperaturne homogenosti referiran na hidraulički dijametar preko 1, u odnosu na faktor homogenosti glatke cijevi (HGØ). U ovom kontekstu, faktori homogenosti se definiraju kako slijedi: In order to achieve a high utilization of olefins with a relatively short pipe length, the process according to the invention should be carried out in such a way that the temperature homogeneity factor across the cross section and the temperature homogeneity factor referred to the hydraulic diameter are over 1, in relation to the smooth homogeneity factor pipes (HGØ). In this context, homogeneity factors are defined as follows:
HGØ[-]HPØ = ΔT0·dx/ΔTx·d0 HGØ[-]HPØ = ΔT0·dx/ΔTx·d0
Konfiguracija strujanja u skladu s izumom, koja se sastoji od jezgrenog strujanja i vrtložnog strujanja, može se postići s rebrastom cijevi u kojoj je bočni kut rebara, koja su u svakom slučaju kontinuirana cijelom duljinom sekcije cijevi, tj, vanjski kut između bokova rebara i radijusa cijevi je 160 do 250, pogodno 190 do 210. Bočni kut ovog tipa, osobito u kombinaciji s nagibom rebra od 200 do 400, na primjer 22,50 do 32,50, osigurava da ono što rezultira u dolinama rebara nije više ili manje kontinuirano vrtložno strujanje koje se vraća do dolina rebara iza bokova rebara i dovodi do stvaranja neželjenih "uvijanja" u dolinama rebara. Bolje je, da turbulencija formirana u dolinama rebara postane odvojenom od bokova rebara i izvodi se pomoću vrtložnog strujanja. Energija vrtloženja inducirana rebrima ubrzava čestice plina i dovodi do više sveukupne brzine. Ovo dovodi do smanjenja temperature metala cijevi, i također čini da je ova posljednja ujednačenija, također čineći temperaturu i vrijeme zadržavanja preko poprečnog presjeka cijevi ujednačenijima. A flow configuration according to the invention, consisting of a core flow and a vortex flow, can be achieved with a finned tube in which the side angle of the fins, which are in any case continuous along the entire length of the tube section, i.e. the outer angle between the flanks of the fins and the radius pipe is 160 to 250, preferably 190 to 210. The side angle of this type, especially in combination with a rib inclination of 200 to 400, for example 22.50 to 32.50, ensures that what results in the valleys of the ribs is not more or less continuous eddy currents that return to the rib valleys behind the rib flanks and lead to the creation of unwanted "twists" in the rib valleys. It is better that the turbulence formed in the valleys of the ribs becomes separated from the flanks of the ribs and is carried out by means of a vortex flow. The vortex energy induced by the fins accelerates the gas particles and leads to a higher overall velocity. This leads to a decrease in the metal temperature of the tube, and also makes the latter more uniform, also making the temperature and residence time across the cross section of the tube more uniform.
Priroda rebraste cijevi u skladu s izumom može se vidjeti iz ilustracije segmenta cijevi na Slici 6 i pridruženih karakterističnih parametara The nature of the ribbed pipe according to the invention can be seen from the illustration of the pipe segment in Figure 6 and the associated characteristic parameters
- Hidraulički dijametar Dh u mm, Ri[Dh/2 - Hydraulic diameter Dh in mm, Ri[Dh/2
- Kut boka β - Side angle β
- Visina rebra H - Rib height H
- Radijus upisane kružnice Ra=Ri + H i Da=2 x Ra - Radius of the inscribed circle Ra=Ri + H and Da=2 x Ra
- Centralni kut α - Central angle α
- Radijus zakrivljenosti R=Ra (sinα/2 sinβ + sinα) - Radius of curvature R=Ra (sinα/2 sinβ + sinα)
- Obod upisane kružnice 2ΠRa - Circumference of the inscribed circle 2ΠRa
- Kut u kosokutnom trokutu γ = 180 - (α+β) - Angle in an isosceles triangle γ = 180 - (α+β)
- Unutarnji radijus Ri=2R (sinγ/sinα) - R - Inner radius Ri=2R (sinγ/sinα) - R
- Visina rebra H=Ra-Ri - Rib height H=Ra-Ri
- Obod profila Up = 2 x broj rebara x πR/180 (2 β+α) - Profile circumference Up = 2 x number of ribs x πR/180 (2 β+α)
- Površina plohe rebra FR - Surface area of the FR rib
- Površina upisanog kruga Fa = π·Da2/4 - Area of the inscribed circle Fa = π·Da2/4
- Površina unutarnjeg kruga Fi = Π·Di - Area of the inner circle Fi = Π·Di
- Površina profila unutar upisanog kruga - Profile area within the inscribed circle
FP = FR · broj rebara FP = FR · number of ribs
- Obod profila Up = (1,05 do 0,98)·2ΠRa - Profile perimeter Up = (1.05 to 0.98)·2ΠRa
Rebra i doline rebara koje su locirane između rebara mogu biti zrcalno-simetričnog dizajna u poprečnom presjeku i spajati se jedna s drugim ili mogu oblikovati valovitu liniju sa u svakom slučaju istim radijusima zakrivljenosti. Kut boka zatim nastaje između tangenti dva radijusa zakrivljenosti na mjestu dodira i radijusa cijevi. U ovom slučaju, rebra su relativno plitka; visina rebara i kut boka se podudaraju jedan s drugim na takav način, da je hidraulički dijametar profila iz omjera 4 x svijetli poprečni presjek/obod profila veći ili jednak od unutarnjeg kruga profila. Hidraulički dijametar je zbog toga u unutarnjoj trećini visine profila. Kao posljedica, visina rebra i broj rebara rastu kako dijametar postaje većim, tako da se vrtložno strujanje održava po smjeru i intenzitetu koji se traže za djelovanje profila. The ribs and rib valleys located between the ribs may be of a mirror-symmetric design in cross-section and join each other or may form a wavy line with the same radii of curvature in each case. The flank angle is then formed between the tangents of the two radii of curvature at the point of contact and the pipe radius. In this case, the ribs are relatively shallow; the height of the ribs and the angle of the side coincide with each other in such a way that the hydraulic diameter of the profile from the ratio 4 x clear cross-section/circumference of the profile is greater than or equal to the inner circle of the profile. The hydraulic diameter is therefore in the inner third of the profile height. As a consequence, the fin height and the number of fins increase as the diameter becomes larger, so that the vortex flow is maintained at the direction and intensity required for the airfoil action.
Između rebara ili u dolinama rebara nastaje veća brzina strujanja (Slika 2), dovodeći do efekta samočišćenja, tj. do smanjenja količina piroliznog koksa koji se odlaže. Between the ribs or in the valleys of the ribs, a higher flow velocity occurs (Figure 2), leading to a self-cleaning effect, i.e. to a reduction in the amount of pyrolysis coke that is deposited.
Ako se rebra proizvode nadogradnjom zavara ili prekrivajućim zavarenim slojem, koristeći centrifugirano lijevanu cijev, stijenka cijevi između pojedinih rebara ostaje u biti nepromijenjena, tako da doline rebara leže na zajedničkoj kružnici koja odgovara internom obodu centrifugirano lijevane cijevi. If the fins are produced by a weld build-up or overlay weld layer, using a centrifugally cast pipe, the pipe wall between the individual fins remains essentially unchanged, so that the valleys of the ribs lie on a common circle that corresponds to the internal circumference of the centrifugally cast pipe.
Testovi su pokazali da je, bez obzira na unutarnji dijametar cijevi, ukupno 8 do 12 rebara dovoljno da se postigne konfiguracija strujanja u skladu s izumom. Tests have shown that, regardless of the inner diameter of the pipe, a total of 8 to 12 ribs is sufficient to achieve the flow configuration according to the invention.
U slučaju rebraste cijevi u skladu s izumom, omjer kvocijenata koeficijenata prijenosa topline QR/Q0 prema kvocijentu gubitakatlaka ΔPR/ΔP0 u testu s vodom, primjenjujući i promatrajući zakonitosti sličnosti i koristeći Reynoldsove brojeve dane za smjesu nafta/para, je pogodno od 1,4 do 1,5, u čemu R označava rebrastu cijev, a 0 označava glatku cijev. In the case of a finned tube according to the invention, the ratio of the quotients of the heat transfer coefficients QR/Q0 to the pressure loss quotient ΔPR/ΔP0 in the test with water, applying and observing the laws of similarity and using the Reynolds numbers given for the oil/steam mixture, is preferably 1.4 to 1.5, where R indicates a ribbed tube and 0 indicates a smooth tube.
Prednost rebraste cijevi u skladu s izumom (profil 3) u usporedbi s glatkom cijevi (profil 0), te s rebrastom cijevi s osam paralelnih rebara (profil 1), između kojih je radijalna udaljenost između dolina rebara i vrhova rebara 4,8 mm, je ilustrirana podacima predstavljenim u donjoj tablici. Sve rebraste cijevi imaju 8 rebara i jednaku upisanu kružnicu. The advantage of a ribbed tube according to the invention (profile 3) compared to a smooth tube (profile 0), and with a ribbed tube with eight parallel ribs (profile 1), between which the radial distance between the valleys of the ribs and the tops of the ribs is 4.8 mm, is illustrated by the data presented in the table below. All ribbed pipes have 8 ribs and the same inscribed circle.
[image] [image]
U ovom kontekstu, hidraulički dijametar je definiran kako slijedi: In this context, the hydraulic diameter is defined as follows:
Dhidr = 4 x (svijetli poprečni presjek)/unutarnji obod; Dhidr = 4 x (bright cross-section)/inner circumference;
on pogodno odgovara unutarnjem dijametru usporedive glatke cijevi i onda rezultira faktorom homogenosti od 1,425. it conveniently matches the inside diameter of a comparable smooth pipe and then results in a homogeneity factor of 1.425.
U testu s vodom, rebrasta cijev u skladu s izumom je dala prijenos topline (QR) koji je bio za faktor 2,56 viši od glatke cijevi, uz gubitak tlaka (ΔPR) koji je bio viši samo za faktor 1,76. In a water test, a finned tube according to the invention gave a heat transfer (QR) that was a factor of 2.56 higher than a smooth tube, with a pressure loss (ΔPR) that was only a factor of 1.76 higher.
Slika 7 uspoređuje tri različita profila cijevi, uključujući cijev u skladu s izumom, s 8 rebara uz nagib od 300 u svakom slučaju, cijev s glatkom unutarnjom stijenkom (glatka cijev). Hidraulički dijametar, aksijalna brzina, vrijeme zadržavanja i gubitak tlaka dani su za svaki poprečni presjek. Figure 7 compares three different pipe profiles, including a pipe according to the invention, with 8 ribs at a pitch of 300 in each case, a pipe with a smooth inner wall (smooth pipe). Hydraulic diameter, axial velocity, residence time, and pressure loss are given for each cross section.
Početni korišteni podaci bili su kvantitativni prolazi u radnoj glatkoj cijevi s unutarnjim dijametrom od 38 mm, koji je identičan s hidrauličkim dijametrom. Koristeći zakonitosti sličnosti (iste Reynoldsove brojeve), ovi su se podaci računski konvertirali za toplu vodu i koristili kao baza za testove (usporedi omjer kvocijenata za prijenos topline i gubitak tlaka za testove s vodom i referirani faktor homogenosti za proračunavanje kod korištenja plinova). The initial data used were quantitative passages in a working smooth pipe with an internal diameter of 38 mm, which is identical to the hydraulic diameter. Using laws of similarity (same Reynolds numbers), these data were computationally converted for hot water and used as a basis for tests (compare the ratio of heat transfer coefficients and pressure loss for tests with water and the referenced homogeneity factor for calculations using gases).
Iz istih kvantitativnih prolaza rezultirali su različiti profili brzina pri različitim hidrauličkim dijametrima (recipročni odnos). Different velocity profiles at different hydraulic diameters resulted from the same quantitative passes (reciprocal relationship).
Usporedba brzina za profile 2 i 3, koji su identičnog poprečnog presjeka, ilustrira poboljšanu brzinu, ubrzanje i vrijeme zadržavanja s cijevima u skladu s izumom (profil 3). Za isti hidraulički dijametar, komponenta brzine u obodnom smjeru, izazvana vrtloženjem induciranim pomoću rebara, izaziva da se strujanje odvaja od stijenke cijevi i inducira spiralno rastuću brzinu preko cijelog poprečnog presjeka. A comparison of the velocities for Profiles 2 and 3, which are of identical cross-section, illustrates the improved velocity, acceleration and dwell time with tubes in accordance with the invention (Profile 3). For the same hydraulic diameter, the circumferential velocity component induced by fin-induced vorticity causes the flow to separate from the pipe wall and induces a spirally increasing velocity across the entire cross-section.
Usmjereno, spiralno strujanje uvodi toplinu iz stijenke cijevi u strujanje i zbog toga ju raspodjeljuje ravnomjernije nego u normalnom, neusmjerenom turbulentnom strujanju (glatka cijev, profili 1 i 2). Isto se primjenjuje na vrijeme zadržavanja čestica. Spiralno usmjereno strujanje raspodjeljuje čestice ujednačenije preko cijelog poprečnog presjeka, dok ubrzavanje kod bokova rebara smanjuje srednje vrijeme zadržavanja. Veći gubitak tlaka uz profil 3 nastaje iz obodne brzine. U slučaju profila 1, uzrok je značajno sužavanje strujanja i gubitak trenja kod velike unutarnje plohe profila. Directed, spiral flow introduces heat from the pipe wall into the flow and therefore distributes it more evenly than in normal, non-directed turbulent flow (smooth pipe, profiles 1 and 2). The same applies to particle retention time. The spirally directed flow distributes the particles more uniformly over the entire cross-section, while the acceleration at the flanks of the ribs reduces the mean residence time. The higher pressure loss along profile 3 results from the peripheral velocity. In the case of profile 1, the cause is a significant narrowing of the flow and loss of friction at the large inner surface of the profile.
Zavisno o materijalu, rebraste cijevi u skladu s izumom se mogu proizvoditi, na primjer iz centrifugirano lijevane cijevi s aksijalno paralelnim rebrima, pomoću krajeva cijevi koji se rotiraju jedan s obzirom na drugi, ili pomoću unutarnjeg profila koji se proizvodi deformacijom centrifugirano lijevane cijevi, na primjer pomoću vrućeg kovanja, vrućeg vučenja, ili hladnom obradom pomoću alata za profiliranje, letećeg vretena i šipke vretena s vanjskim profilom koji odgovara unutarnjem profilu cijevi. Depending on the material, finned tubes according to the invention can be produced, for example, from a centrifugally cast tube with axially parallel ribs, by means of tube ends that rotate with respect to each other, or by means of an internal profile produced by deformation of a centrifugally cast tube, on for example by hot forging, hot drawing, or cold working using a profiling tool, a flying spindle and a spindle bar with an external profile matching the internal profile of the pipe.
Poznato je nekoliko varijanti reznih strojeva za unutarnje profiliranje cijevi, na primjer iz Njemačkog patenta 195 23 280. Ovi su strojevi također prikladni za proizvodnju rebraste cijevi u skladu s izumom. Several variants of cutting machines for the internal profiling of pipes are known, for example from German patent 195 23 280. These machines are also suitable for the production of ribbed pipes according to the invention.
U slučaju vrućeg oblikovanja, temperatura deformiranja bi se trebala podesiti tako, da se mikrostrukturno zrnce djelomično razori u području unutarnje plohe i da se u skladu s tim prekristalizira u kasnijoj fazi pod utjecajem radne temperature. Rezultat je toga fino zrnata mikrostruktura koja dopušta brzu difuziju kroma, silicija i/ili aluminija kroz austenitnu matricu do unutarnje plohe cijevi, gdje se oksidni zaštitni sloj zatim brzo stvara. In the case of hot forming, the deformation temperature should be adjusted so that the microstructural grain is partially destroyed in the area of the inner surface and accordingly recrystallizes at a later stage under the influence of the working temperature. The result is a fine-grained microstructure that allows the rapid diffusion of chromium, silicon and/or aluminum through the austenite matrix to the inner surface of the tube, where an oxide protective layer is then rapidly formed.
Rebra u skladu s izumom, se također mogu proizvoditi nadogradnjom zavara; u ovom slučaju nije moguće oblikovati zakrivljenu bazu rebara između pojedinih rebara, već se izvorni profil unutarnje stijenke cijevi u velikoj mjeri održava. Ribs according to the invention can also be produced by welding; in this case, it is not possible to form a curved base of the ribs between individual ribs, but the original profile of the inner wall of the pipe is largely maintained.
Unutarnja ploha cijevi u skladu s izumom bi trebala imati najmanje moguću hrapavost; zbog toga se ona može zagladiti, na primjer mehanički polirati ili elektrolitički izravnati. The inner surface of the pipe according to the invention should have the least possible roughness; therefore, it can be smoothed, for example mechanically polished or electrolytically smoothed.
Prikladni materijali za uporabu u postrojenjima za etilen su legure željeza i/ili nikla koje sadrže 0,1% do 0,5% ugljika, 20 do 35% kroma, 20 do 70% nikla, do 3% silicija do 1% niobija, do 5% volframa i dodatke hafnija, titana rijetkih zemalja ili cirkonija, u svakom slučaju do 0,5% i do 6% aluminija. Suitable materials for use in ethylene plants are iron and/or nickel alloys containing 0.1% to 0.5% carbon, 20 to 35% chromium, 20 to 70% nickel, up to 3% silicon, up to 1% niobium, up to 5% tungsten and additions of hafnium, rare earth titanium or zirconium, in any case up to 0.5% and up to 6% aluminium.
Claims (36)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10233961A DE10233961A1 (en) | 2002-07-25 | 2002-07-25 | Cracking hydrocarbon materials in presence of steam heated with pipes having helical inner ribs promoting uniform temperature in pipe wall |
PCT/EP2003/004827 WO2004015029A1 (en) | 2002-07-25 | 2003-05-08 | Method and ribbed tube for thermally cleaving hydrocarbons |
Publications (1)
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HRP20050072A2 true HRP20050072A2 (en) | 2005-08-31 |
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HR20050072A HRP20050072A2 (en) | 2002-07-25 | 2005-01-24 | Method and ribbed tube for thermally cleaving hydrocarbons |
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EP (2) | EP1525289B9 (en) |
JP (2) | JP4536512B2 (en) |
KR (1) | KR101023668B1 (en) |
CN (1) | CN100523133C (en) |
AT (1) | ATE526385T1 (en) |
AU (1) | AU2003227737A1 (en) |
BR (1) | BR0312919B1 (en) |
CA (1) | CA2493463C (en) |
DE (1) | DE10233961A1 (en) |
EA (1) | EA010936B1 (en) |
ES (1) | ES2374568T3 (en) |
HR (1) | HRP20050072A2 (en) |
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MA (1) | MA27325A1 (en) |
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NO (1) | NO337398B1 (en) |
NZ (1) | NZ537827A (en) |
PL (1) | PL204769B1 (en) |
PT (1) | PT1525289E (en) |
RS (1) | RS20050060A (en) |
UA (1) | UA85044C2 (en) |
WO (1) | WO2004015029A1 (en) |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
PL2037202T3 (en) | 2006-07-05 | 2019-03-29 | Nippon Steel & Sumitomo Metal Corporation | Metal tube for thermal cracking reaction |
EP2408551A1 (en) * | 2009-03-17 | 2012-01-25 | Total Petrochemicals Research Feluy | Process for quenching the effluent gas of a furnace |
EP2813286A1 (en) * | 2013-06-11 | 2014-12-17 | Evonik Industries AG | Reaction tube and method for the production of hydrogen cyanide |
FR3033266B1 (en) * | 2015-03-05 | 2017-03-03 | Ifp Energies Now | COLLECTION ASSEMBLY OF A GASEOUS FLUID FOR RADIAL REACTOR |
WO2017007649A1 (en) | 2015-07-09 | 2017-01-12 | Sabic Global Technologies B.V. | Minimizing coke formation in a hydrocarbon cracker system |
JP6107905B2 (en) * | 2015-09-09 | 2017-04-05 | 株式会社富士通ゼネラル | Heat exchanger |
CN109072090B (en) * | 2016-04-12 | 2021-03-16 | 巴斯夫安特卫普股份有限公司 | Reactor for cracking furnace |
DE102016012907A1 (en) | 2016-10-26 | 2018-04-26 | Schmidt + Clemens Gmbh + Co. Kg | Deep hole drilling method and tool for a deep hole drilling machine and deep hole drilling machine |
DE102017003409B4 (en) | 2017-04-07 | 2023-08-10 | Schmidt + Clemens Gmbh + Co. Kg | Pipe and device for the thermal cracking of hydrocarbons |
EP3384981B1 (en) * | 2017-04-07 | 2024-03-06 | Schmidt + Clemens GmbH + Co. KG | Tube and device for the thermal splitting of hydrocarbons |
WO2018185167A1 (en) * | 2017-04-07 | 2018-10-11 | Schmidt + Clemens Gmbh + Co. Kg | Pipe and device for thermally cleaving hydrocarbons |
CA3062425C (en) * | 2017-05-05 | 2022-05-31 | Exxonmobil Chemical Patents Inc. | Heat transfer tube for hydrocarbon processing |
CA3079647A1 (en) * | 2017-10-27 | 2019-05-02 | China Petroleum & Chemical Corporation | Heat transfer enhancement pipe as well as cracking furnace and atmospheric and vacuum heating furnace including the same |
GB2590363B (en) * | 2019-12-09 | 2023-06-28 | Paralloy Ltd | Internally profiled tubes |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB969796A (en) | 1961-03-01 | 1964-09-16 | Exxon Research Engineering Co | Apparatus for heating fluids and tubes for disposal therein |
JPS58132081A (en) * | 1982-01-08 | 1983-08-06 | Idemitsu Petrochem Co Ltd | Thermal cracking of hydrocarbon |
DE3716665A1 (en) * | 1987-05-19 | 1988-12-08 | Vdm Nickel Tech | CORROSION RESISTANT ALLOY |
JP3001181B2 (en) * | 1994-07-11 | 2000-01-24 | 株式会社クボタ | Reaction tube for ethylene production |
DE4427859A1 (en) * | 1994-08-05 | 1995-10-26 | Siemens Ag | Tube with inner ribbing forming multi-hand thread |
DE19523280C2 (en) * | 1995-06-27 | 2002-12-05 | Gfm Gmbh Steyr | Forging machine for internal profiling of tubular workpieces |
DE19629977C2 (en) * | 1996-07-25 | 2002-09-19 | Schmidt & Clemens Gmbh & Co Ed | Austenitic nickel-chrome steel alloy workpiece |
DE69802404T2 (en) * | 1997-06-10 | 2002-07-18 | Exxon Chemical Patents, Inc. | PYROLYSIS OVEN WITH INTERNAL U-SHAPED RIBBED RADIANT COIL |
JPH11199876A (en) * | 1998-01-16 | 1999-07-27 | Kubota Corp | Thermal cracking pipe used for producing ethylene having coking-reducing performance |
-
2002
- 2002-07-25 DE DE10233961A patent/DE10233961A1/en not_active Withdrawn
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2003
- 2003-05-08 AT AT03725176T patent/ATE526385T1/en active
- 2003-05-08 PL PL373967A patent/PL204769B1/en unknown
- 2003-05-08 CN CNB038178850A patent/CN100523133C/en not_active Expired - Lifetime
- 2003-05-08 RS YUP-2005/0060A patent/RS20050060A/en unknown
- 2003-05-08 EA EA200500258A patent/EA010936B1/en not_active IP Right Cessation
- 2003-05-08 CA CA2493463A patent/CA2493463C/en not_active Expired - Lifetime
- 2003-05-08 ES ES03725176T patent/ES2374568T3/en not_active Expired - Lifetime
- 2003-05-08 MX MXPA05001070A patent/MXPA05001070A/en active IP Right Grant
- 2003-05-08 WO PCT/EP2003/004827 patent/WO2004015029A1/en active Application Filing
- 2003-05-08 KR KR1020057001384A patent/KR101023668B1/en active IP Right Grant
- 2003-05-08 EP EP03725176A patent/EP1525289B9/en not_active Expired - Lifetime
- 2003-05-08 UA UAA200501718A patent/UA85044C2/en unknown
- 2003-05-08 PT PT03725176T patent/PT1525289E/en unknown
- 2003-05-08 NZ NZ537827A patent/NZ537827A/en not_active IP Right Cessation
- 2003-05-08 AU AU2003227737A patent/AU2003227737A1/en not_active Abandoned
- 2003-05-08 JP JP2004526658A patent/JP4536512B2/en not_active Expired - Lifetime
- 2003-05-08 EP EP10012045A patent/EP2298850A1/en not_active Withdrawn
- 2003-05-08 BR BRPI0312919-5A patent/BR0312919B1/en active IP Right Grant
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- 2005-01-18 MA MA28048A patent/MA27325A1/en unknown
- 2005-01-24 HR HR20050072A patent/HRP20050072A2/en not_active Application Discontinuation
- 2005-01-28 NO NO20050493A patent/NO337398B1/en not_active IP Right Cessation
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PT1525289E (en) | 2012-01-04 |
BR0312919B1 (en) | 2014-06-24 |
RS20050060A (en) | 2007-09-21 |
PL373967A1 (en) | 2005-09-19 |
DE10233961A1 (en) | 2004-02-12 |
MXPA05001070A (en) | 2005-10-05 |
EP2298850A1 (en) | 2011-03-23 |
NZ537827A (en) | 2007-04-27 |
IL166229A (en) | 2008-11-26 |
NO337398B1 (en) | 2016-04-04 |
KR20050052457A (en) | 2005-06-02 |
MA27325A1 (en) | 2005-05-02 |
JP2010150553A (en) | 2010-07-08 |
JP4536512B2 (en) | 2010-09-01 |
ATE526385T1 (en) | 2011-10-15 |
WO2004015029A1 (en) | 2004-02-19 |
BR0312919A (en) | 2005-07-05 |
JP2005533917A (en) | 2005-11-10 |
EA200500258A1 (en) | 2005-08-25 |
PL204769B1 (en) | 2010-02-26 |
AU2003227737A1 (en) | 2004-02-25 |
KR101023668B1 (en) | 2011-03-25 |
UA85044C2 (en) | 2008-12-25 |
ES2374568T3 (en) | 2012-02-17 |
NO20050493L (en) | 2005-03-17 |
CA2493463A1 (en) | 2004-02-19 |
EA010936B1 (en) | 2008-12-30 |
IL166229A0 (en) | 2006-01-15 |
EP1525289B9 (en) | 2012-02-29 |
EP1525289B1 (en) | 2011-09-28 |
EP1525289A1 (en) | 2005-04-27 |
CA2493463C (en) | 2013-01-15 |
CN1671824A (en) | 2005-09-21 |
CN100523133C (en) | 2009-08-05 |
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