Cinetica di reazione

syn N.

a

2PNH 3 J

-k PNHl-a

2

2 J

0.20 F-

KMI 1.5-3mm

=10%

NH3 conc.%

Figure 7. Reaction rate for NH 3 synthesis. Dependence onthè ammonia concentration at various pressures.

0.15

0.10oE

t 0.05

KMI 1.5-3mmI n e r r s =10%H?:N2 ,3=1NH3 conc- i2%

30MPa

400 500T e m p e r a t u r e , °C -

600

Figure 8. Reaction rate for NH3 synthesis. Dependence onthè temperature at various pressures.

Lezioni di Chimica Industriale — Ammoniaca

Configurazioni possibili

Makejp gas

'Dd rtì e

Pur gè

®b

»NH

Purge e

— »-!

•

,^

^.

3S

-L^J

,̂4e " 3

1!

d

T

ì-id^euu yd

A

Purge gas

i

i

^

J

h

I

NH3 %

\

Makeup gas

d

Purge gas

i

e NH3

»— £ —

© iNH,

a

I

Figure 25. Schematìc flow diagrams of typìcal ammonia synthesis loopsA) Synlhesis loop for pure and dry makeup gas; B) Produci recovery after recycle compression; C) Produci recovery beforerecycle compression (four-nozzle compressor design); D) Two stages of produci condensationa) Ammonia converter with heat exchangers; b) Ammonia recovery by chìliing and condensation; e) Ammonia recovery bycondensation at ambierà temperature; d) Synthesis gas compressor; e) Recycle compressor

Lezioni di Chimica Industriale — Ammoniaca

Reattori per la sintesi

FIG. 18. Simplified converter design.

» raffreddamento delle pareti>Gas freschi (annulus tra tubo di forza e cestello per il

catalizzatore» Scambiatore interno'Profilo termico poco controllabile

Lezioni di Chimica Industriale —Ammoniaca

Reattore Fauser

STEAMiOUT

WATER IN

FIG. 14. Fauser-Montecatini water-cooied converter of earlydesign. (Courtesy of Montecatini-Edison.)

VANTAGGIControllo termico ottimale'Massima conversione

SVANTAGGI'Gestione sistema di raffreddamento

Lezioni di Chimica Industriale —Ammoniaca

Quench type reactors

FIG. 19. Siraplified quench converter design.

©

600 -

100 200 300 (.00 500 600 O

Temp.. °C -

Figure 37. Multibecl converter with quench cooling [650]A) Converter, a) Catalyst; b) Heat exchanger; e) Quench gas inlets; d) Gas inlet; e) Gas exitB) Gas temperature profile through thè converter;C) Ammonia concentration versus temperature (cf. Fig. 30)

5 10 15c o n t a n t , voi8/. ——•

Lezioni di Chimica Industriale —Ammoniaca

Profilo termico nel reattore2

E i,

-C•" iv 6

=0

100 200 300 400 500 600Temp., °C »-

5 10 15 20NH3 c o n t e n t . volVo

Figure 31. Countercurrent tube-cooled converter (TVA converter) [480]A) Converter layout; a) Catalyst; b) Heat exchanger; e) Coolmg tubes; d) Main gas inlet; e) Vesseì Wall cooling gas iniefO Temperature control gas (cold-shot) inlet; g) Gas exitB) Gas temperature profile through thè converter; C) Ammonia concentration versus temperature (cf. pie. 30)

5 10 15NH3 correrti-. vol°/0

20 2S

rigure 32. Parallel-flow tube-cooled converter [480]V) Converter; a) Catalyst; b) Heat exchanger; e) Cooling tubes; d) Gas inlet; e) Temperature control gas (cold-shot) inlet;) Gas exit5) Gas temperature profìle through thè converter;J) Ammonia concentration versus temperature (cf. Fig. 30)

600

500

1.00

30000 600 5 10 15

NH3 contenf . voi"/»20

-"igure 33. Muitibeti covwerier wiih indireci cooling\ > Converter; a) Catalyst; b) Heat exchanger; e) Cooling section; d) Gas inlet; e) Temperature control gas (cold-shot) inlet;") Gas exiti) Gas temperature profile through thè converter;J) Ammonia concentration versus temperature (cf. Fig. .10)

Lezioni di Chimica Industriale —Ammoniaca

Reattori industrialiA-Gasinlet E - Gas from extwrtì stai ̂ temer•*Qni«dttthMtMBMry F-QuandiCintetiC-Gasexit G • Pyranro-D- Oraci b^pass H - Cataiy* dxtep noale

FIG. 21. (A) ICI quench-type converter, designed especiallyfor high-level iieat recovery.

Topsoe| /^ff/fj

OUTIET I.C.I.

FIG 21. (B) ICI opposed-flow quench converter.

:rr:,,, nvz£^

L ^-ZV / / // tf~7

.«.li '

Kellog "orizzontale"

FIG. 21. Sinplified Topsoe two-bed radiai quench converter.

Lezioni di Chimica Industriale - Ammoniaca