0 ,1
3.
Kuydirilgandan ke
yingi qoldiq. k o ‘pi
bilan
0 , 0 0 1
0,0 03
0,005
4.
Sulfatlar (
S O ] ' )
0 , 0 0 0 2
0,0005
0 , 0 0 2
5.
Fosfatlar ( P O
4
")
0 , 0 0 0 0 2
0 , 0 0 0 2
0 , 0 0 2
6
.
Xloridlar (Cl)
0,00005
0 , 0 0 0 1
0,0005
7.
T cm ir (F e)
0 , 0 0 0 0 2
0 , 0 0 0 1
0,0003
8
.
Kalsiy (C a)
0,0005
0 , 0 0 1
0 , 0 0 2
9.
Mishyak (As)
0 , 0 0 0 0 0 2
0,00 0003
0 , 0 0 0 0 1
1 0
.
Og‘ir metallar (Pb)
0 , 0 0 0 0 2
0,0005
0,0005
K o n s e n t r l a n g a n a z o t ki slotasi G O S T 5 1 1 8 7 - 7 2 ni ng q uyi da gi
t al abl ar iga j a v o b b e r m o g ‘i ker ak. U l a r q uyi da gi 9 . 3 - j a d v a l d a kel
tirilgandir.
9 .3 -ja d v a l
K O N S E N T R L A N G A N A Z O T K I S L O T A S I F A T I G A G O S T 5 1 1 8 7 - 7 2
B O ‘Y I C H A B O ‘L G A N TAL A B L A R
T /r
Tarkib
O 'lc hov birligi, %
Miqdor
1
.
Azot kislotasi
( H N O
3
)
98,9
2
.
Azot oksidlari
N
2
O
4
b o ‘yicha
hisoblaganda
0 , 2
3.
Sulfat kislotasi
( H
2
S O
4
)
0,0 4
4.
Kuydirilgandan keyingi qoldiq
0,006
9.6. A Z O T K I S L O T A S I N I S A Q L A S H VA T A S H I S H
K u c h s i z a z o t kislotasi z a n g l a m a y d i g a n p o ‘l a t d a n yasa lga n saql a-
g i c h l a r d a s a q l a n a d i . O d a t d a b u n d a y kislota a s o sa n sh u a z o t ki sl o t a
sini ishlab c h i q a r g a n k o r x o n a n i n g o ‘z i da ishlatiladi.
253
Kuc hli az ot kislotasini sa q la s h u c h u n esa a l u m i n i y d a n yasa lga n
yoki q o p l a n g a n i dishlarda saql ana di va a l umi niyl i si st er n a l a r d a tashi -
ladi. A m m o , k o ‘p i n c h a kuchl i a z o t kislotasini m e l a n j k o ‘r i n i s h i d a
tashiladi. M el an j quyidagi tarkibdagi: 89% H N 0 3, 7 , 5 % H , S 0 4 ( 92%
li sulfat k i s l o t a d a n ) va 3 , 5 % H 20 d a n ibor at a r a l a s h m a d i r .
9. 7. A Z O T K I S L O T A S I N I A M M I A K D A N I S H L A B C H I Q A R I S H
VA U N I N G A S O S I Y B O S Q I C H L A R I
K u c h s i z a z o t kislotasi y u q o r i d a b a y o n q i l i ng a n i d e k , hozirgi
v a q t d a a s os a n a m m i a k d a n ishlab c h i q a r i l m o q d a va u q u yi da gi u c h
b o s q i c h d a n i boratdir.
1. A m m a k n i az ot m o n o o k s i d i o l g u n g a q a d a r oksidlash:
4 N H 3 + 5 0 2-> 4 N O + 6 H 20 + 9 0 7 kJ
(9.5)
Az ot m o n o o k s i d i n i a z o t di ok s i d i ga q a d a r oksi dl ash:
2 N O + 0 2
f
^ 2 N 0 2 + 124 kJ
(9.6)
1.
Az ot d i oks idi ni suv b i lan abs or bsi ya la b, k uc h s i z az ot kislotasi
olish:
3 N 0 2 + H 20
f
* 2 H N 0 3 + N O + 136 kJ
(9.7)
Bu u c h i n c h i b o s q i c h d a ajralib c h i q a y o t g a n a z ot m o n o o k s i d i ik
ki nc h i b o s q i c h b o ' y i c h a y a n a q a y t a d a n a z o t d i o k s i d i g a q a d a r ok s i d -
lanib, u c h i n c h i b os qi ch b o ‘yi cha y a na q a y t a d a n suv bilan absor bsiya-
lani b, q o ‘s h i m c h a a z o t kislotasi o li n ad i . Bu q o ‘s h i m c h a j a r a y o n
kerakli m a r o t a b a g a c h a qayt ar i la di .
Az ot kislotasi hosil b o ‘lishining u m u m i y reaksiyasi shartli r avishda
q u y i d a g i c h a i fodal anis hi m u m k i n :
N H 3 + 2 0 2 = H N 0 3 + H 20
(9.8)
A m m o , a m a l i y o t d a a z ot kislotasini (9.8) reaksiya b o ‘y i c h a hozirgi
d a v r g a c h a ishlab c h i q a r i lg a n e ma s .
9. 8. A M M I A K N I K O N T A K T L I O K S I D L A S H N I N G
F I Z I K - K I M Y O V I Y A S O S L A R I
A z o t kisl otasini si nt et i k a m m i a k d a n i shlab c h i q a r i s h n i n g u c h t a
b o s q i c h i d a n b i r i n c h i s i d a y u q o r i d a t a ’ki dl ab o ‘t i l g a ni d e k , a s o s a n ,
quyi dagi reaksiya ketadi:
4 N H 3(g) + 5 0 2(g) = 4 N O (g) + 6 H 20 (b) + 907 kJ
(9.5)
254
В и r e ak si ya g o m o g e n , e k z o t e r m i k , a m a l i y q a y t m a s d i r . A m m i a k
ni k is l or od b i l a n o k si d l a n i s h reaksiyasi j a r a y o n i a n c h a g i n a m u r a k -
kab b o ‘lib, u n d a b i r v a q t n i n g o ‘z i da quyi dagi parallel reaksi yal ar
h a m ketishi m u m k i n :
4 N H 3(J)+ 4 0 2(1) = 2 N 2O u) + 6 H j O (b) + 1105 KJ
(9.9)
4 N H J(8)+ 3 0 2|e| = 2 N 2(g) + 6 H 20 (b) + 1270 kJ
(9. 10)
4 N H 3(gl + 6 N O (g) = 5 N 2(g) + 6 H 20 (b) + 1810 kJ
(9. 11)
Bu ( 9 . 9 )— ( 9. 11) r e a ks iya l ar h a m g o m o g e n , e k z o t e r m i k va a m a
liy q a y t m a s d i r . I s hl ab c h i q a r i s h s h a r o i t i d a n a f a q a t (9.5) reaksi yani,
balki ( 9 . 9 ) — ( 9. 11) r e a k s i ya l a r n i ng m u v o z a n a t l a r i h a m t o ‘liq o ‘ng
t o m o n g a siljigandi r. Bu esa yaxshi e m a s , c h u n k i a m m i a k n i ( 9 . 9 ) —
( 9 . 1 1 ) r e a k s i y a l a r b o ‘y i c h a o k s i d l a n i s h i q i m m a t b a h o a m m i a k n i
b e h u d a s ar f b o ‘lishiga olib keladi. Bu esa ishlab c h i q ar i l a y o t g a n azot
kislotasi t a n n a r x i n i n g o sh i b ke t i sh i ga olib kel adi , b u n g a asosiy sa-
b a b sh u ki , ( 9 . 9 ) —(9. 11) re aksi yal ar ketishi n a t ij as id a e l e m e n t a r azot
yoki N 20 hosil b o ‘lib, az ot kislotasi hosil qilish u c h u n z a r u r b o ‘lgan
az ot m o n o o k s i d i N O hosil b o ‘l ma ydi .
Y u q o r i d a t a ’ki dl ab o ‘t ilg an i de k, ( 9. 5), ( 9 . 9 )— (9. 11) r e ak si ya l ar
n i n g b a r c h a s i a m a l i y q a y t m a s va u l a r m u v o z a n a t i na z ar i y j i h a t d a n
o ' n g g a siljigan b o ' l i s h i m u n o s a b a t i b i l a n , j a r a y o n n i n g a ma l i y ot d ag i
u m u m i y y o ‘nalishi yuqor i dagi reaksiyalar tezliklari nisbati bilan a ni q-
l a n a d i . I s h l a b c h i q a r i s h s h a r o i t i d a u yoki bu re aksi yani tezligini
o ‘z g ar t i ri s h g a er ishi sh u c h u n t a n l o v xususi yat iga ega b o ‘lgan ka t a-
l i z a t o r l a r d a n b i r o n ta s i q o ‘ll anadi.
S h u n i h a m t a ’kidlash ker akki , h e c h q a n d a y k a t a l i z a t o r q o ‘llanil-
m a g a n d a a m m i a k n i a t m o s f e r a havosi dagi ki sl or od b il an reaksiyasi
o ‘z - o ‘z i c h a (9. 10) reaksiya b o ' y i c h a e l e m e n t a r az o t hosil qilish bilan
k e t a d i ; b u n g a esa , y u q o r i d a a y t i l g a n i d e k , u m u m a n y o ‘l q o ‘yib
b o ‘l m a y di . A m m o , ( 9. 5), ( 9 . 9 )— (9. 11) k i my o vi y re aksi yal ar ketishi
n at ij as id a ajralib c h i q a y o t g a n issiqliklar a m m i a k n i a t m o s f e r a h a v o
sidagi kislorod bi lan b or a d i ga n oksidlash j a r a y o ni ni a vt ot er mi k t ar z da
ol ib b o r i s h u c h u n b a t a m o m yetarlidir.
(9. 5), ( 9 . 9 ) — ( 9. 10) re aksi yal arni a m a l g a os hi ri sh u c h u n kisl orod
ker ak; t o z a k i s lo ro d hozi rgi v a q t d a h a m n i s b a t a n q i m m a t ekanligi
tufayli, y u q o ri d ag i r e aksi yal arni a m a l g a os hi ri sh u c h u n a m a l i y o t d a
a t m o s f e r a havosi ishlatiladi. M o d o m i k i s h u n d a y e k a n , a m m i a k - h a v o
a r a l a s h m a s i d a g i a m m i a k m i q d o r i k i s l o r o dn i n g h a v o da g i m i q d o r i g a
bo g' li q. A g a r d a a z o t kislotasi quyi dagi j a m l o v c h i shar tl i ravishdagi
reaksiya:
255
N H 3 + 2 0 2 = H N O , + H 20
(9.8)
natijasida oli nadi d e b hisoblasak, u v aqt da t arki bi da 21 (h) % kislorod
b o ‘lgan a t m o s f e r a havosi va a m m i a k d a n i bo r at b o ‘lgan a r a l a s h m a -
da a m m i a k n i n g o p t i m a l h a j m i y mi qd or i :
9 , 5 % ( h) ni tashkil e t a r ek a n.
Bu m i q d o r n i t ex n o l o g i k n uq ta y i n a z a r d a n tahlil qilish quyi dagi
h ol at l ar ni v uj udga keltirishi m u m k i n . B i r i n c h i d a n , bu m i q d o r azot
kislotasi u n u m d o r l i g i n u qt ay i n a z a r i d a n n i s b a t a n ki chi k m i q d o r b o ‘-
lib, y uq or i r oq u n um d o r l i k k a ega b o ‘lish u c h u n a m m i a k - h a v o ar alash-
m as i da a m m i a k n i n g mi q d o r i n i o s h i r m o q kerak. A m m o b u n d a a m m i
a k - h a v o a r a l a s h m a s i d a a m m i a k n i n g m i q d o r i 15,8 (h)
% —
25, 6 (h)
% o ra li g‘i d a n t a s h q a r i d a b o ‘l m o g ‘i ker ak, aks h o l d a va j u d a ki chi k
o ' l c h a m d a u c h q u n r o ‘y b e r g a n d a , n a f aq a t a z o t kislotasi sexi, balki
bu sexl ar a t r o f i d a o ‘r n a t i l g a n sexl ar h a m p o r t l a b ket ishi m u m k i n .
B u l ar ni e ’t i b o rg a o l g an h o l a t d a i shlab c h i q a r i s h s h a r o i t l a r i d a
a m m i a k - h a v o a r a l as h ma s i d a 0 2 : N H 3 = 1,7—2, 0 b o l g a n d a a m m i a k
n in g a m a l i y m i q d o r i 9, 5 — 11,5 (h) % d a n o s hi b ket is hi ga y o ‘l
q o ‘yilmaydi.
9.9.
A M M I A K N I S E L E K T I V O K S I D L A S H
KATALI ZATORLARI , U L A R N I N G Z A H A R L A N I S H I
VA T I K L A N I S H I
A m m i a k n i a t m o s f e r a havosi t a r k i b i d a g i k i s l o ro d b i l a n y u q o r i
t e m p e r a t u r a l a r d a h e c h q a n d a y k a t a l i z a t o r qoMlamay olib b o ri l ga n da ,
oksi dl ash j a r a y o n i (9. 10) va (9. 11) r e ak si ya l ar b o ‘y i c h a faqat e l e
m e n t a r a z o t hosil qilish b i lan bor a di.
Tabi iyki , az ot kislotasi ishlab c h i q a r i s h d a a m m i a k n i oksi dl ash
j a r a y o n i n i t a n la s h, y a ’ni selektivlik xususiyat iga ega b o ‘lgan kat al i za
t o r l a r i s ht ir okida olib bo ri sh m a q s a d g a m uv o f i q . B u n d a s h u n d a y
k a t a l i z a t o r l a r q o ‘llash ker akki , u la r a m m i a k n i oksi dl ash y u q or i d ag i
r e ak si ya l ar i d a n, a s os a n , N O hosil qilish b i lan b o r a d i g a n (9.5) r e ak-
si yasi ni ng tezligini b o s h q a r e a ks iya l ar tezligiga q a r a g a n d a t o ‘s a t d a n
os hi ri shga olib kelsin. Bu b o r a d ag i ilmiy i z l an i sh l ar s h u n i k o ‘rsat-
diki, ka t al i za to r l ar sifatida quyidagi metall yoki ular oksidlari i shlati
lishi m u m k i n eka n: Pt, C o 20 4, F e , 0 3, C r 20 3, M n , 0 3, N i O , C u O .
2 1
С
1 0 0 ( x ) % = 9 , 5 ( x ) %
(9-12)
256
S h u n d a y qilib, b u k a t a l i z a t o r l a r i c h i d a n az ot kislotasi ishlab c h i
q ar is h u c h u n e n g z a r u r b o ‘lgan k o m p o n e n t l a r d a n biri — a z o t m o
n o o k s i d i N O ni y u q or i tezl ik b il an hosil b o ‘li shini t a ’m i n l a y d ig a n
k a t a l i z a t o r b u — p l a t i n a k at al iz a to ri dir .
P l a t i n a — q i m m a t k at al i za to r , a m m o u k o ‘p vaqt m o b a y n i d a
o ‘zi ni ng n i s b a t a n yuqori aktivligini saqlaydi, yetarli da r aj ada c h i d a m -
li, m a ’l u m m e x a n i k m u s t a h k a m l i k k a ega, n i s b at a n yengil t i kla na di ,
t e z qi zi yd i v a l a g ‘c h a c h o ‘g ‘ h o l a t i g a keladi v a e n g asosiysi —
m a h s u l o t birligidagi sarfi a n c h a g i n a kichi kdir.
A m m o , a m a l i y o t d a k a t a l i z a t o r si fat ida hozi rgi d a v r d a t oz a p l a
t i n a e m a s , b al ki u n i n g pal ladi y, r odi y va b o s h q a m e t a l l a r bi lan hosil
qi lgan q o t i s h m a s i ishlatiladi. N a t i j a d a k a t a l i z a t o r n i n g m e x a n i k m u s -
t a h k a m l i g i o r t a d i , b u es a k a t a l i z a t o r n i y o ‘q o l i s h i n i k a m a y t i r a d i .
B u n d a n t as hq a r i b u n d a y q o t i s h m a l a r i shl at il ga nda N O n in g chiqishi
t o z a p l a t i na q o ‘l langani dagi ga q a r a g a n d a , 2 , 5 —3 , 0 % ga ortishi isbot-
langan. S h u n i n g u c h u n h a m hozirgi vaqt da G O S T 3193-59 ga b i n o a n
G I A P - 1 m a r k a l i p l a t i n a + 4 ( massali) % Pd + 3,5 ( massali) % Rh
d a n i bor at k a t a l i z a t o r a t m o s f e r a b o s i m d a va p l a t i n a + 7,5 (massali)
% Rh d a n ibor at kat al i za to r yuqori b o s i m d a ishlaydigan az ot kislotasi
q u ri lma s id a i shl at il moqda. Plat ina katalizatorlari y o ‘g ‘onligi 0, 09 m m
d a n iborat 1 s m 2 y u za da 1024 ta j u d a m ay d a kat ak ch al ar hosil qiluvchi
i n gi c h k a s i m d a n t o ‘qi lgan t o ‘r s ha k l i d a ishlab c h i q ar i la d i.
Yangi t o ‘r lar tekis, y al ti ro q va elastik simli i p c h a l a r d a n t o ‘qilgan
b o ‘lib, b u k a t a l i z a t o r l a r ishl ab c h i q a r i s h j a r a y o n i d a k o ‘p ishlatilishi
nati jasida xiralashib, g ‘a d i r - b u d u r hol at ga o ‘tib, si ml ar tashqi k o ‘rini-
shi n i s b a t a n y o ‘g ‘o n l a s h i b ul ar ni t ashqi va i chki yuzalari j u d a t a-
r aqqiy t o p g a n b o ‘ladi. B u n i n g nat ij asi da N O n i n g chi qi shi bi roz
o r t a d i , a m m o k a t a l i z a t o r n i n g m e x a n i k m u s t a h k a m l i g i p a s aya di va u
s ek i n - a s t a y e m i r i l a b o shl aydi . 0 ‘z i n i n g dastlabki massasini 12% d a n
k o ‘p b o ‘l m a g a n m i q d o r i n i y o ‘q o t g a n k a t a l i z a t o r q a y t a e r i t i s h ga
j o ‘natiladi.
Q i m m a t b a h o pl atinali ka t al i za to r ni az ot ki slotani olishdagi nisbiy
sarfini k a m a y t i r i s h g a e r i s h i s h m a q s a d i d a oxirgi yillari a m m i a k n i
at mos fe r a havosidagi kislorod bilan oksidlash j a r a y o n i d a ikki bosqichli
kat alizator q o ‘llash ma q s ad g a muvofiq deb topildi. Bu vaqtda u m u m i y
kat al iza tor q a t l a m i ikki q a t l a m d a n , y a ’ni platinali t o ‘r d a n iborat ustki
q a t l a m h a m d a qalinligi 5 0 —60 m m b o ‘lgan pl a t i na s i z pastki q a t l a m
d a n i bo r at di r . B u n d a y k a t a l i z a t o r n i q o ‘llash p l a t i n a n i bir v a q t ni n g
o ‘zidagi sarfini u c h m a r o t a b a k a m a y t i r i s h ga olib ke l ar eka n. A m a l i
y o t d a p l a t i n a k at a l i za t o r i n i m e x a n i k t a r z d a y o ‘qol is hi h a m mavj ud.
M a ’l u m k i , a m m i a k n i selektiv k a t a l i za t o r l a r q o ‘llab o ks idl ab, azot
1 7 -
257
m o n o o k s i d i n i hosil qilish j a r a y o n i 1123 К — 1193 К l a r d a olib b o -
riladi. B u n d a y y u q or i t e m p e r a t u r a l a r d a u c h u v c h a n p l a t i n a dioksidi
hosil b o ‘l ishide k va b u n d a n t a s h q a r i, a m m i a k - h a v o a r a l a s h m a s i n i n g
k a t t a c hi z i q l i t e z l ik l ar i n a t i j a s i d a p l a t i n a k a t a l i z a t o r i n i b ir q i sm
za rra chal ar i t o ‘g ‘ri dan t o ‘g ‘ri y o ‘qoladi d ega n t a x m i n l a r h a m mavjud.
P la t i na k a t a l i z a t o r i n i ng y o ‘qol i s hi ni k a m a y t i r i s h u c h u n b iz n in g
f i kri mizcha, uch y o ‘li bor. Birinchisi — b u bi r q i s m platinali kat al iza
t o rn i n i s b a t a n a r z o n r o q va t opilishi o s o n r o q b o ‘lgan k at a l i za t o r l a r
yoki u la r q o t i s h m a l a r i b il an a l m a s h t i r i s h ; i kki nc hi si — p l a t i n a z a r-
r a c h a l a r i n i u sh l ab olish va ul ar ni q a y t a d a n k a t a l i z a t o r t a y y o r l a sh d a
q o ‘llash; u c h i n c h i s i — z a h a r l a n g a n k a t a l i z a t o r l a r n i re ge n e r at si ya l a b
t o za l a s h va q a y t a ishlatish.
P l a t i n a n i n g m a y d a z a r r a c h a l a r i n i u s h l ab q ol i s h u c h u n g a z oqi mi
b o ' y i c h a k a t a l i z a t o r t o ‘r la r ida n keyin j o y l as h t i r i l g a n o ‘tga c h i d a m l i
metall oksidlari q at la mi ni ishlatish mumkinl igi ad a biy o tl ar da k o ‘rsatib
o ‘tilgan. H oz ir gi v a q t d a kalsiy oksi di a s o si d a p l a t i n a n i n g u m u m i y
y o ‘q o l i s h i n i 7 0 —80% ini u sh l ab qol i s hi ni t a ’m i n l a y d i g a n ma s s al a r
ishlab c h i q i l g a n va u l a r s i n o v d a n o ‘tgan.
Platinani ushlab qoluvchi massani kalsiy oksidi kislorod ishtirokida
p l a t i n a b i l an q u y i d a g i c h a r eaksiyaga kirishishi m u m k i n :
x C a O + Pt + 0 2 = x C a O - P t 0 2
(9. 13)
Kalsiy oksi di a s o s id a t a y y o r l a n g a n m a s s a d a n u s h l ab q o l i n g a n
p l at i n a n i re g en er at s i ya qilib aj ratish b o s h q a ma s s al a r n i r egener at siya
q i l i s h d an o s o n r o q .
A m m i a k n i bir tekisda, o ‘z g a r m ay ok si dl an i sh in i t a ’m i n l a s h u c h u n
a m m i a k - h a v o a r al ashmasi m e x a n i k a r a l a s h m a l a r d a n , ayniqsa, a m m i
a k si ntezi j a r a y o n i d a q oMl anadi ga n t e m i r k a t a l i z a t o r l a r i c h a n g i d a n
j u d a c h u q u r t o z a l a n g a n b o ‘l m o g ‘i ker ak. C h a n g va t e m i r oksi dlari
p l at ina kat al izatori t o ‘rlariga kirib, ularni ifloslaydi, nati jada a m m i a k -
havo ar al as hma s i n in g katal iza tor sirti bilan u ch r a s h is h yuzasini k a m a -
yishi sodir b o ‘ladi, bu esa oxi r- oqi bat a m m i a k n i oksi dlanish darajasini
h a m pa s ayis hi ga oli b keladi. B u n d a n t a s h q ar i , b u c h a n g l a r k a t a l i z a
t o rn i u s h l ab q o l uv ch i m as sa o r a la r i ga h a m ki rib, u l a r yuzasini o ‘rab
olib, p l at i n a n i u s hl ab qol ish dar aj asi ni h a m k a m a y i s h i g a oli b keladi.
Platinali katalizatorl ar at mos fe r a havosi va a m m i a k d a g i h a r q a n d a y
i fl osgarchi li kka j u d a h a m sezgirdirlar.
S in t e t i k a m m i a k , y u q o r i d a eslatib o ‘t i l g a ni d e k , t e m i r yoki b o s h
q a qatt iq m o d d a l a r c h a n g l a r i d a n t ashqar i, o ‘z t ar ki bi da h a r xil m oy la r
h a m d a a m m i a k k ont akt li ok s id l as h b o ‘l i mi ga yetib k e l g u n c h a bir
258
q a t o r a p p a r a t l a r va q u v u r l a r d a n o ‘t a y o t g a n i d a t o ‘p l a n i b q o l ad i ga n
h a r xil a r a l a s h m a l a r b o ‘lishi m u m k i n . H a v o n i n g t a r k i b i da esa az ot
kislotasi ishlab c h i q a r a d i g a n sex yoki z a vod atrofidagi h a v o d a boMishi
m u m k i n b o ' l g a n q a t t i q va gazli a r a l a s h m a l a r — t e m i r oksi dl ari ,
q u m l a r , fosfatli t u z l a r , b u s e x d a n yoki q o ‘s h n i s e x l a r d a n ajralib
c h i q u v c h i ase ti l en , xlor, ug l er o d m o n o o k s i d i , v o d o r o d xloridi, o l tin-
g u g u r t d i ok s i di , m e t a n v a b o s h q a ga z la r b o ‘lishi m u m k i n .
H a v o va a m m i a k n i c h a n g va a r a l a s h m a l a r i d a n t o z a l a s h u c h u n
a t m o s f e r a b o s i m i d a i shl aydi gan az ot kislotasi q u r i l m a l a r i d a a m m i a k
movut li m a t o orqali filtrlanadi, bosi m ost ida ishlaydigan q u ri l ma l ar d a
esa asbestli m a t o yoki g a z la m a l i k a r t o n or qa li f i ltrlanadi. G a z l a r n i
t ozal as h u c h u n g ‘ovak s o po l d a n yasalgan q u v u r c h a l a r h a m ishlatilishi
m u m k i n . D a s t l a b k i a m m i a k - h a v o a r a l a s h m a s i n i t e m i r o k s i d l ar i d a n
iborat c h a n g l a r bilan ifloslanishiga y o ‘l q o ‘ymasl ik u c h u n az ot kislota
q u r i l m a s i b o ‘yl ab y u q o r i d a g i g a z a r a l a s h m a s i y u r a d i g a n k o n t a k t
a p p a r a t i g a c h a b o ' l g a n b a r c h a a p p a r a t l a r va q u v u r l a r n i z a n g l a m a y
d i ga n p o ' l a t d a n y a s a s h ga h a r a k a t qilinadi.
A m m o , k o ‘ri layot gan b a r c h a c h o r a l a r g a q a r a m a y , k at al iza tor vaqt
o ‘tishi b i lan a s t a - s e k i n z a h a r l a n i b b or a d i va n a t i j a d a a z ot m o n o o k
si dini c h i q i s h i pas ay i b qol adi.
Platinali kat al iza tor l arni ng ma ks ima l ishlash vaqti ul arda oksi dl an-
g a n a m m i a k n i n g m i q d o r i bil an o ‘l ch a n a di . 1103 К — 1123 К t e m p e
r a t u r a l a r d a u c h q a t l a m l i k a t a l i z a t o r t o ‘r i ni ng ishl ash vaqt i 1 g r a m m
t o ‘r d a 1 5 0 0- 1 6 0 0 kg a z o t kislotasi i shlab c h i q a r i s h g a , 1173 К —
1203 К t e m p e r a t u r a l a r d a esa k o ‘p q a t l a m l i k a t a l i z a t o r t o ‘r lar ini ng
ishlash m u d d a t i 1 g r a m m t o ‘r da 1300— 1400 kg a z o t kislotasi ishlab
c h i q a r i s h u c h u n k e t g an v a qt ga t engdi r.
A t m o s f e r a b o s i m i d a i s hl aydi ga n q u r i l m a l a r d a a m m i a k n i ok s i d -
l aydi gan p la t i na l i k a t a l i z a t o r n i n g ishlash m u d d a t i k a t a l i z a t o r t o ‘rlari
a l m a s h t i r i l m a g a n h o l d a 12— 14 o y n i , 7 — 8 a t m o s f e r a b o s i m i d a
ishlaydigan q u r i l m a l a r d a esa 8 —9 oyni tashkil etadi. Platinasiz kat al i
z a t o r l a r n i n g i shlash m u d d a t i 3 —5 yilga t engdi r.
H a r xil kat al it ik z a h a r l a r va iflosliklardan t ozal as h u c h u n platinali
k a t a l i z a t o r l a r v a q t i - v a q ti b i lan v o d o r o d xlorid kisl ota sini ng 10— 15%
li e r i t m a s i d a 333 К — 343 К t e m p e r a t u r a d a 2 — 3 soat m u d d a t d a
farforli yoki kvarsli k a t t a k o n c h o ‘z i n c h o q i di sh da r e g e n er a t s iy a qi li
n a d i . S o ‘ng p l a t i n a l i t o ‘r lar d i s t i l l a n g a n suv b i l a n yuvi ladi , toki
y u v i s h d a n k e y i n hosi l b o ‘l a y o tg a n su vd a x l or i oni y o ‘q b o ‘l gunga
q a d a r ; s o ‘n g r a bu t o ‘r lar qur i ti la di va v o d o r o d gazi a l a n g a s i d a k uy-
diriladi. R e g e n e r a t s i y a d a n s o ‘ng k a t a l i z a t o r t o ‘r lar ini ng faolligi y a na
q a y t a t i k l a n a d i va deya r l i dast labki m i q d o r i g a yet adi .
259
9. 10. A M M I A K N I A Z O T M O N O O K S I D I G A O K S I D L A N I S H
M E X A N I Z M I
A m m i a k n i h avoda gi ki sl or od b i l a n N O hosil qilishi or qa li b o r a
d i g an (9 . 5 ) reaksiyasi g a z f a za s i da b o r u v c h i g o m o g e n r e aksi yani
tashkil e t s a - d a , a m m o bu j a r a y o n n i t ezlatish u c h u n q a t t i q k a t a l i z a
t o r n i n g q o ' l l a n i s h i u m u m i y j a r a y o n n i g e t e r o g e n katalitik j a r a y o n deb
atal ishi ga o l ib keladi.
A m m i a k n i N O g a c h a ok s i d l an i s h i m e x a n i z m i n i t u s h u n t i r i s h d a
b ir n e c h t a n az a ri y al a r ma v j u d. U l a r d a n biri a d s o r b s i o n - k i m y o v i y
n a z a r i y a b o ‘lib, b u n a z a r i y a g a b i n o a n ga z f a z a s i d a k i s l o r o d n i n g
m i q d o r i s t e x i o m e t r i y a g a n i s b a t a n k o ‘p b o ‘l gan s h a r o i t d a a m m i a k n i
o ks i d l a n i s h j a r a y o n i quyi dagi b o s q i c h l a r d a n tashki l t o pg an :
1. R e a ks iya ga k ir is huvc hi m o d d a l a r n i u m u m i y gaz ma s s a s i da n
ajralib c h i q i b , k a t a l i z a t o r n i n g t as hqi yuza si ga kelishi;
2. Bu m o d d a l a r n i k a t a l i z a t o r n i n g ichki yuz a si ga diffuziyasi;
3. A d s o r b s i y a l a n g a n m o l e k u l a l a r n i k a t a l i z a t o r yuzasi b i lan o ‘z a -
ro t a ’siri;
4. R e a k s i ya g a ki ri shgan m o d d a l a r n i k a t a l i z a t o r n i g ‘o v a k l a r i d a n
u n i n g sirtqi yuza siga diffuziyasi;
5. Reaksi ya m a h s ul o t l a r i n i k a t al i za to r n i ng t as hq i yuz a si da n u m u
mi y ga z o q i m i g a o ‘tishi.
Bu b o s q i c h l a r d a n qaysi b i r i ni n g tezligi e n g ki ch i k b o ‘lsa, xuddi
s h u b o s q i c h tezligi ok si dl an is h j a r a y o n i n i n g u m u m i y tezligini belgi-
laydi. I l mi y i zl an i s hl ar s h u n i k o ‘rsa tya pti ki , a m m i a k n i ok s i d l an i s h
reaksiyasi tezligi a v v a l a m b o r kislorod va a m m i a k n i k a t a l i z a t o r y u z a
siga diffuziyasi tezligiga b o g ‘liq ekan. Keyingi t ekshiri shlar y a n a shuni
k o ‘rsatdiki, platinali k a t a l i za t o r yuzasiga a m m i a k n i diffuziyasi tezligi
kislorod diffuziyasi tezl igi dan ki chi k ek an . S h u n d a y qilib, a m m i a k n i
platinali kat al i za to r isht ir okida N O g a c h a oks idl ani sh j a r a yo n i tezligi
a m m i a k n i k at al iza tor yuzasiga diffuziyasi tezligi bilan belgi lanar ekan.
A g a r d a g a z f a z a s i d a k i s l o r o d n i m i q d o r i s t e x i o m e t r i k n i s b a t
0 2: N H 3 = 5:4 ga t e n g b o ‘lsa, a m m i a k n i ok si dl an is h u m u m i y tezligi
k is lo ro d ni plat inal i k a t a l i z a t o r yuza siga diffuziyasi tezligi b il an bel-
gilanishi a n i q l a n g a n .
A m m i a k n i pl at inal i k a t a l i z a t o r i s h t i r o k i da N O g a c h a o k s i d l a n i
shi j a r a y o n i m e x a n i z m i b ir q a t o r o ra l i q r e a ks iya l ar or qa li ketishi
tegishli a d a b i y o t l a r d a n m a ’l um.
N O n i n g a m m i a k n i oksi dl ash n a t ij as ida hosil b o ‘lishi bir q a t o r
t ex n ol o gi k o m i ll a r g a b o g ‘liq: a m m i a k - h a v o a r a l a s h m a s i n i k a t a l i z a
t o r b il an u c h r a s h i s h v aq t i , o k si d l a n i s h j a r a y o n i d a q o ‘l l an a y o t g a n
b o s i m , das t l ab ki gaz a r a l a s h m a s i n i n g tozaligi va ho ka z ol ar .
260
9. 11. A M M I A K - H A V O A R A L A S H M A S I N I PLATI NA
KAT A L I Z AT O RI BI LAN U C H R A S H I S H VAQTI
A z o t kislotasi ishlab c h i q a r i s h u c h u n z a r u r b o ‘lgan asosiy k o m
p o n e n t l a r d a n biri b o ‘lgan N O ni hosil qilish u c h u n a m m i a k - h a v o
a r a l a s h m a s i a l b a t t a p l a t i n a kat al i za to ri q a t l a m i d a n o ‘t m o g ‘i kerak.
A m m i a k n i b e r i l g a n d a r a j a d a o ks i d l a n i s h ig a e r i s h m o q u c h u n a m m i
a k - h a v o a r a l a s h m a s i n i k a t a l i z a t o r b i lan u c h r a s h i s h vaqt i q a t ’iyan
a n i q b o ‘l m o g ‘i ker ak. Bu v a q t k a t a l i z a t o r n i n g h a j m i va dastl abki
g a z a r a l a s h m a s i n i n g a m m i a k n i o k si dl as h s ha r o i t i d ag i vaqt bi rl i gi da
gi h a j m i y sarfiga b o g ‘liq b o ‘lib, q uyi da gi t e n g l a m a b o ‘y i c h a h is ob -
l an i sh i m u m k i n :
T = V b , / V „ .
(9.14)
bu yer da: r — gaz a r al a s h ma s i n i n g kat al iza tor z o n a s i d a b o' l i s h vaqti,
sek;
Vkal — k a t a l i z a t o r n i n g o z o d h aj m i , m 3,
Vgaz— oksi dl ash s har oit idagi g az a r a l a s h m a s i n i n g vaqt b i r
ligidagi h a j m i y sarfi, m 3/ s e k .
A m m i a k - h a v o a r al as hma s ini kat alizat or z o n a s i d a b o ‘lish eng qulay
v aqt i 0, 00001 s e k u n d b i lan 0, 0001 s e k u n d o r a l i g ‘ida boMishi a m a l i -
y o t d a n t o p i l g a n . G a z o q i m i chi zi ql i tezligini k a mayt ir i li shi dastlabki
g a z a r a l a s h m a s i n i n g k at a l i za t o r z o n a s i d a b o i i s h va q ti n i oshirilishiga
va bu es a N O o ‘rniga e l e m e n t a r a z o t hosil b o ‘lishiga ol ib keladi.
A k s i n c h a , g a z o q i m i n i n g chizi qli tezligi qu l ay m i q d o r i d a n oshi ri b
y u b o r i l s a , g a z a r a l a s h m a s i n i k a t a l i z a t o r z o n a s i d a b o 4 i s h vaq t i ni
k a mayt ir a di . Bu esa hosil b o ‘layotgan ni tr oza gazlari o q i mi ga d a s tl ab
ki a m m i a k - h a v o a r al as hma s i, a n i q r o g ‘i a m m i a k n i o ‘tib ketishiga olib
keladi. Bu o ‘tib k e t ga n a m m i a k n i t r oz a gazi t ar ki bi dagi N O bilan
re aksi yaga kirishib, e l e m e n t a r a z o t hosil qiladi:
4 N H 3 + 6 N O = 5 N 2 + 6 H 20 + 1810 kJ
Bu a m m i a k n i n g b i r q is mi n i t r o z a gazlari t a r ki bi da g i , N O , bilan
reaksiyaga kirishib, a m m o n i y nitriti va a m m o n i y nitratini hosil qiladi.
Y u q o r i t e m p e r a t u r a l a r d a N H , o ‘zi h a m p a r c h a l a n i b , e l e m e n t a r N 2
hosil qilishi m u m k i n :
2 N H 3 = N 2 + 3 H 2 - 9 1, 6 kJ
(9.15)
A m m o n i y nitriti va a m m o n i y ni trat i h a m y u q or i t e m p e r a t u r a l a r
d a p a r c h a l a n i s h i n at ij as ida e l e m e n t a r az ot va N , 0 hosil b o ‘lishi
m u m k i n .
261
Y u q o r i d a g i r e a ks iya l ar n a t i j a d a q i m m a t b a h o a m m i a k n i n g m a ’
l u m b i r q is mi y o ‘q ol adi . Bu esa o ‘z n a v b a t i d a i shl ab c h i q ar i l a y o t g a n
azot kislotasi t an n ar x i ni ng oshi b ketishiga olib keladi. B u n d a n t a s h q a
ri, k a t a l i z a t o r n i n g t o ‘rlari or qa li o k s i d l a n m a y o ‘tib k e t a y o t g a n a m
m i a k n i n g b i r qismi t e m p e r a t u r a s i p a s t r o q b o ‘lgan z o n a l a r g a c h a yetib
b o r i b , a m m o n i y nitriti va a m m o n i y n it r a t l a r i n i hosil qilishi m u m
kin, u l a r esa b i r - b i ri ga i s h q a l an ib t u r u v c h i y u z a l a r g a t u s h i b qol ib,
p o r t l a s h n i keltirib c hi qa r i s hi m u m k i n .
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