DE1667718A1 - Process and burner for converting ammonia into nitrogen oxides - Google Patents

Description

H. SCHROETIR K

IMOndia SS · UpoJkyttf. IO. TcL 778996

bi-az-1 « I2.IO.I967

SOCIXtB BELOB DE L * AZOIB WS 013 PROIHTXTS CmmqUBS DU MAELT, SA :, 21 «rue de ftenory, - 0 ug ν% ; · (B}

Process and burner for the conversion of. Amnonial " in Stiekoxyde

The present invitation concerns a vexier Ünmandluag -von AmmonieJc in Stiakoxde eowie dl Burners dispatched to this conversion «ground.

In the course of the catalytic oxidation of Aassoniak, several reactions can take place, although the predominant reaction is that which leads to the formation of -90a HO according to the following equation: NHj + - | O ₂ —-—> NO ♦ \ HgO + 54 Koal leads, which is atarfe exothera. y \ - '/. J - .

, τ · ■■ ·

In the presence of the platinum catalyst, the oxidation of ammonia to nitrogen oxides takes place at a temperature of 750 - 90O ⁰ C in 10 " ⁴ " to 1O ~ ⁵ seconds »

Since the price of the waste materials is the main part As regards manufacturing costs, it is clear that the effectiveness of the conversion of ammeniac is a very important problem in view of this plays on the economy of the process.

The effectiveness of the oxidation of As & monia to nitrogen oxides depends on several factors, so one can assume that for a specific catalyst and oxidation pressure, the Yield of stickocytes for a given smear - »of ammonia and will depend in particular on the following factors:

- homogeneity of the mixture, '■■ -... ~ Dependency of the distribution of the mixture on the catalyst

cloths,

- speed of passage a de? Mieehung by the catalytic converter,

- Absence of VOQ coavection currents or vortices that cause germinated, dad a file below the Kavalytatorttluher formed stiococytes above this ^ iie & he rises.

The catalyst comes in the form of cloths or sets made of platinum or platinum-rich alloys, which is why it is absolutely necessary for the economy of the process that the Consumption ar>. Platinum per Sun formed nitric acid so low as possible iat «One of the conditions to be observed for the purpose of Avoidance of activites / fcslueten of the catalyst is ea, both mechanical and thermal damage to the · Katalya & tortUcher Avoid 2U.

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BATH

The procedure and the burner gtmEB Invention allow this © multitude of settings realize.

Pas procedure ordered la essential in it, the homogeneous mixture of ammonia with air on the catalysis? -VV ⁵ · tlieher directs and then which the £ atalye & to? £ Uohe? leaving an oxidizing gas. Loss of load. Yegsi'gsweiae the gaseous mixture of ammonia tsnd Xuft la tin © Tielsahl is divided by parallel flows in front of d @ & Durotogsas fereh dta catalyst »

The for this purpose ^ ö3? Ends @ v @ 5? ^ik@3.o Issaaer in which the gases flow from above to u ^ @ n contains fetslfsatortüoher, which is carried by a £ euerfestezt f © s> moestaadigea fesa © - • werdsa, dia ait canals in the form vsa Büsea vere & hss, 4 © t sad tie vaa seitsa äer Eatalysatortüoher a miaimal "Ofeer £ lSe | i <§ awei" bssaelibartea canals, feraer ice perforatedBS BIeoh and / or

Until purposes uad Vorteil® d®s t fahrens- ^ rdea from the following BteolMM ^ tbaag.ΐ ^, - δ ■ loo ^ ashs »on the drawing ersiohtlioh.

In Fig.1 is a vertical fuel burner shown, with d @ m one the invented geeliS® Terfahrez. can perform. Tig.2 «elgt on a large scale Sinas © lJ3.ei% e? I the Pig.ι ». "

This burner consists of a chamber 1 in the form of a diffuser for feeding the gaa-shaped reaction mixture made of ammonia and air to the catalytic converter Z made of fiatine. See a vertical burner with circulation of the gaseous stream from above to below.

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At a corresponding distance of about 1/3 to 1/4 of the diameter of the catalyst tube in the sealing upwards, a perforated plate 5 is attached in the diffuser, which is welded directly to the wall of the diffuser. For example, a sheet of 2 mm thick can be used with 2 mm holes spaced 6 - 7 am apart. At the same height as the perforated bleoh. If the inlet 7e is between this metal sheet and the layer of the catalyst, a metallic grid 4 is attached which, for example, consists of wire with a diameter of 2 mm and a distance of 6 mm between the washes. The metallic lattice is preferably attached near the catalyst cloth, for example at a distance of about 1/2 of the diameter dieaea S6.taiy &Äi; or1-Uüiiö3. .

Xiiose Za '<ialyaB. ^J <iOv \ i \ iQhof made of platinum or an alloy based on *? O & platinum rest & ui a fauerfeeten, fora-resistant, üa-ierlago §, dia mil: K & nälen δ In JOx-m you Dtletn is provided. The cbers? It ^ ji «of this document znieenen swei Duee'n lies in the form aoharfar Kaxttca vcr · 2« eo £ üi Verimeiaung the wear and tear of the atoröuches Z by ΑΌιΊβΰ btfijder BfirUarusg der eoharfen of the new '* expensive * underlay 5 aanieohen cloth and a difevDüterXage groflaaechigeB Betallgitter one that beeitst a latigiiuiiüv hurieonisale small surface, in particular to a grid with twisted ö M * aohenverwendet, ■ wia it in the? ig _e 2 is shown.

In 3iesen Brenner, maa duroh runs the Spitee of Dilfuseirrs 1 a litechation of AnaBoniak and Luft, where "the

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Content of the mixture of ammonia: 9.5 to 11.5 percent bulky liegte this mixture at about 150 - 20Q ⁰ C may be preheated, is under a pressure which ζwieeheη atmoephä riaehem pressure and may be 10 atm "

It successively crosses the openings dee perforated sheet 3 and βοdann the metal grid 4 in such a way, that when it hits the catalyst doors 2, the homogeneous Amaoniafc-air mixture. into a multitude of parallel strums divided at the same speed 1st and thereby one homogeneous loading of the catalyst with a minimum there is turbulence,

The ammonia is oxidized on contact of the catalyst and increased sish due to the exothermic reaction the temperature in the downward direction from the catalyst aue seen and reached a value that lattes special a? unktioa des Amaoniakgeha] tea of the BeaktionsBlsoauag iet ·

The Q & a, containing stlococytes, »that revolves around the catalytic Oxidation of the ammonia formed lets traversed the channels 6, which in the pore of Süaea in the refractory sub » situation 5 are "

At the exit of the burner, the Sas usually enters a heat exchanger eweoks warmerUokwissnung.

Due to the combination effects of the following characteristics: - homogeneous, uniform distribution of the gaseous Affisaoniak-Luft-Iäisoausß perforated on the catalyst with the help of d @ s EIeeheβ and the Ketallgittnrs

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^. progressive; * change in the cross-section of the channels which the Refractory base traverse, with minimal horizontal Reflection surface of the base on the basis of the predetermined frofilierueg these channels

-des 3elath "mg3Vsr.Lu $ te3j wel.3h to the oxidizing gas suffer, as soon as they are formed, you can set up, since none Wirtel orei * Staustrü «e vreder form in the gaseous mixture, The slide reaches the Kotalysatortuch go, if necessary that it for training of xonvectin currents of the Ozydationagaee towards the Diffuse * coincides. despite the vast difference between the temperatures above and below the catalyst cloth to rule.

It was observed that in the absence of the metal lattice 4, the gas stream reaching the catalyst cloths escapes damming currents and there is a different amount of flow. Incidentally, measurement is also expressed by an uneven color tone of the XUsher, which shows that d & B on these warmer and colder zones -presence, as su thermisöfeen leads to damage and a rapid degradation of the suer4 In these catfish one obtains increased catalyst losses and a reduction in the yield in the oxidation of ammonia oxides.

If, on the other hand, refractory blocks or similar equipment are used as a base for the catalyst door, with a certain horizontal heflexion surface, then an uneven distribution of the ammonia-air mixture is observed. Konvektioasstrume then form, with part of the nitrogen oxides formed rising into the diffuser and there with ammonia, ammonium nitrate, etc. / © S @ r ammonium nitrate.

1 09 8 3 0/14 89

This Seize gelengen with da si "Ss-Estrem the Eatedye &tc" - tücner where they dia "csilrren and eiae fortsctrslie-ade.?; Liability cause reduction of the catalyst a.

Pas f olgsade 'aiabt- © teecaräRicende example "diopt sösnäh" r * n Explanation of the'Erlindtssag ·

Ib der Uiffiaseur, äsr εΛ -itr tip has a Heigssg ^^ wialrel of € 0 °, füJsyt aiaa 1700 t & / k ftajspaieJt ia icro eia «r Kisofeuag: sit 10.5 Vc-I.-jt Aaacsaiafe» saä 89.5 V © .! · - ** a · I> ieee ISisshung «eist« ias ft®s «@ ^ * tisr Voa» twg, 140 ⁰ C

Sruck from "5 ata"".f" M & m ..XLsebttng heads iaes durca äse perforated "KUeJb. 3 _f daa directly aa ils Wsad 4®e Bifiiseeure indicated let" Dieees Bl ^^ ö. ^ Os 2 »β, DiÄ® «Si Ige & rra vca 2 asm in distance" »on 6 mm fceflnde-t sica 0.65 ss οδ-e ^^ lfe Kat8.1ysatortüc! 3er 2» Me gssf ^ s ¹ ©.!? «Isiech'jag directs esm durcb dna KstaUgittesr 4 »-das su» Srsiit eit- 2 asa Durehjcaeeer uaö. AbstSn3. «52i τ» ca 6 just lick ösa Ka «eii« ab ^ etefet «to 0.20 a above the" Katalyeatcrtaehts "sang ^ aohf 3it.

The catalytic converter »it eistm Dnroluseeeer roa 2 λ vsstex · 2vieohenBea * ltBS ^ eiaae öitters 8 sit TerdrilUrea on eia« sr fsuerfeetOB TTaterlejje 70 «. 50 »ac ESfee, which is provided with 6 channels, which have a width of $ 0 ms at the Hives.u der searcher υΒΛ of 15» a at the Aüatritteeade aufireieea.

"The at the top dee XJiilueewrs s'jgeftSij.rte äonogeae GaÄBischu»! ^ Is divided into a multitude of peralle lea StrÖttea AUlwiindigiceit gle.i ^ haaaSig etva 0 * 75 as / aec. " by directing them through the sheet 3 and the grid 4 * Bai d *? - the Kätglysatoriillnher is & * v Amäbaiak oxidized

the temperature rises to about 850 ⁰ C. Hie aο formed aitroeen oasis has a Geaoiwiindigkeit voa etna 2.75 a / see uad __

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suffer a loss of loading when passing through the nozzles 6, whereupon their speed reaches 45 m / eee

Due to the absence of heterogeneity in the mixture subjected to catalysis, the oxidation of ammonia to nitrogen oxides can reach or even exceed a yield of 96% (which is a puncture of the ammonia content in the ammonia mixture).

If, on the other hand, one works in the absence of the device (Elfech 3 and (Jitter A) , which ensures the distribution of the gaseous mixture, or if one omits the fire-proof base described above, then one observes a considerable drop in the yield in the region of 10 Jie

In the inventive working method, the platinum Losses very little and are considerably below τρη 100 mg per ton of nitric acid produced.

.109830 / 1489

Claims (4)

bi-az-10 10/12/1967 SOCIETE BELQB DE L1AZOIE ET DES PR0DUIT3 CHIMIQÜESnfe'ÄraS, S.A. 2I4 rue de Renory, - O u gre e (BELQIEN) * Claims 1 .. Process awr conversion of Amraojiiaä: into nitrogen oxide * by catalysis before oxidation in the often-ware of platinum heaters in a Yert.tkalfcrenner, in which the "Gaaa atrötnsn from top to bottom, thereby f; ek <ann? Anat, Aass aan The vioiaogeneous mixture of amonick and air in "iue Tielr.aixl -ψon Strbiiea with uniform cinaclwiadigkeit -vor de" divides the catalyst; and dlüsm gives the preserved rose oases a load leaked directly next to the catalyst - 2. A method _f NaOH claim 1, gekennseiohnet characterized by passing the gaseous Mieohung of ammonia and air through a non-serving ale catalyst playDee sheet and / or Itotallgitter, which are arranged above dee Satalyeatcrs, after which the nitrous G-aae passes durch.Cüaen 1 which form the passageways of a refractory base «on which the platinum cloths lie. 3. Vertical burner aur oxidation of ammonia naoh claims 1 and 2, in which the gases flow from top to bottom, thereby known that it has a ■ in the upper part - ίο- Diffueeur for the supply of the gaseous mixture of ammonia and air, furthermore a perforated plate and then a metal grid, which are attached above the Katalyaatortüoher, eowi. = -Iv <* fireproof base for these cloths, the base through channels in the form of nozzles and has a minimal, horizontal surface above the side of the towels. ' ■ 4 burner according to claim 3, characterized in that that there is a metal grid between the refractory base and the last catalyst cloth.