Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
7 ~
`
PROCl~SS FOR PROllUCING HYDROGEN-CON~AINING GAS
~hd pressnt inv~ntion r91ates tD eonvf~rsiDn of ahydrrJ
carbon faedstock and, more particularly, to a prDcass for
prDducing a hydrDgen-containing ga9.
~he prasent invention is u93ful in the prDductiDn Df .: .
: ammDnia, mf3thanol, higher alcDhDls and hydrDgen. . -;
~: Known in the art are num3r3us processes fDr the prDduc~
tion Df a hydrDgen-cDntaininggag, ~Dr example, a proce99
~?~ ~for prDducing a nitrDgen-hydrogen mixture (US, A, 3441393)
which comprisf3s preheating of a starting vapDur-hydrocarbDn
j mlxture by the heat of cDmbustiDn products, a steam con~
version in the first stage in the presf3nce Df a catalyst ~ ~-
~: at a temperature Df frDm 400-540C to 750-850C due t~ the -~
beat Df cDmbusbion product9 at whioh up tD 70% r3f the star~
tin8 hydroearbon feed is reacted, cDnversion in the second
~: stag~ effacted Dn a catalysb with air supply, th~ cDnver- ~ ~:
sion prDducts at the Dutlet from th0 second stag~ of con~
v~rsiDn having bemperatur9 of 920 to 1,050C. .. :~
:~ Known in the art is a proc099 for prDducing a ni~rDgen-
- -hydrogen mi~ture (GB, A, 2082623) comprising pr~heating:. .
of bhe sbarting steam-hydrocarbDn mixture by the heat
, .,
~ from flue gas0s, a catalytical steam cDnversion in the
A~ first:stage wherein up to 20-50~ Df the starting hydrDcarbDn :.
fe~d reacbs and which i9 effected at a temperature of from -~-.. `~
400 tD 650-750C ansured by the heat Df th0 products Df : :
combustiDn Df tha heating gas~ a process Df a catalytical `
~: steam eo~v0rsi~n in tha s0eDnd stage wherein 50 to 2~o Df .-
the sbarting hydroearbon feed are reacted and which is .~ ;~
' , ~ , "'~
~,~C,~ id,
-2-
effeeted at a temperature of o50-750C tD 750-850C due t~
an indireet heat frDm a heat-transfer frDm the prDduets
f cDnversiDn Dbtained after bhe third stage of cDnversion
n a eatalyst with air supply, the eDnversiDn prDduets after
the third cDnversiDn sta~e having temperature Df 920 to 1,050C.
~ his prior art proeess for the prDductiDn of a
nitrD~en-hydrDgen mixture as cDmpared tD US, A, 3441393 has
advantages residing in a reduction, by 30%, Df the cDn-
.
sumptiDn Df natural gas eDnsumed fDr heating, a more ef~feetlve, as eompared tD US, A, 3441393, eDnversiDn in the
first stage whieh enables a redueed, by 100-150C, temperature
of the prDees~ as eDmpared bD the steam eonversiDn eonditiDns
: deseribed in US, A, 3441393. ;.;~
HDwever, in earrying out this prDeess it is necessary
: bD use an increased amDunt of a catalyst due tD inefficiency
; of the proeess Df a steam conversiDn in the first stage;
moreDver, there is a pressure drDp between the reaetion
; mi~ture and the cDmbustiDn prDducts, instability ~f the`
.-
~ steam eDnversiDn eonditiDns in bhe seeDnd sta~e due to fluc~
:~ tuatiDns of the temperature~ cDnditions of the e4nversion ~` -
prDduets at the outIet frDm thethird stage, a consi~
`~ derable rate of consumption Df the hydrDcarbDn feedstDck -~
fDr maintaining temperature Dptimal for the prDcass in the ` : `
first stage o~ cDnversion dua tD an insufficient amDunt `~ ~
~ Df~heat brDught by the current Df prDcess air intD:the ~ ~ -
: : third stage Df cDnversiDn. `:~
::,.'"'
2 ~ 2 ~
_
KnDwn in the art is a prDcess fDr prDducing a synthe-
sis-gas for the prDductiDn Df ammDnia from hydrDcarbDns
(US, A, 4376758) comprisings preheating Df the starting ~ ~:
hydrDcarbDn feed; separatiDn Df the starting steam-hydrocar-
bDn mixture inbD two streams cne Df which is subjected tD :~
, .
a steam cDnversion in th~ Pirst staga by the heab of a fuel
gas, while in the secDnd stage the prDcess of cDnversiDn
is cond.ucted with an excess D~ air tD ~ive a nDn-stDichiomat- :~
ric mixturs fDr the synthesis of ammDnia; the secDnd
stream D~ the starting hydrDcarbDn f~ed is subjected tD -~
a steam conversiDn with a d~grae Df 90-95% due bo an in~
direct heat-exchange with a nitrDgen-hydrDgen mixture ob~
tained by mixing the first stream Df the converted gas. . .;
after the second 5tage and the secDnd stream after the`.
procass of steam cDnv~rsiDn0 ~his mixture Df both str3ams `~``. `
has a cDmpDsiti~n suitable fDr the synthesis Df a~mDnia
with~ut any further treatment0
~his prDcess has an advantage Dver that Df US, A,
3441393 in reduction Df the co~sumption Df hydrDcarbDns
fDr heating by about 30~0. . `-
However, this prDcess features an inefficient use Df
a catalyst durlng the steam cDnversioP Df bDth sbraams o~
the steam-hydrDcarbDn iLixture, a considerable cDnsumptiDn
of hydr~carbon3 for ha_ting, a gr3at conten`t of inart
methane ln th~ nitrDgen-hydrDgen mixture Df the secDnd
straam due tD carryinJ DUt the process Df conversion in a . ...
single stage with severe temperature conditions.
~ , , , ,: '
,~j
~ 2 ~ ~3~ L~ ~
-4-
Known in the art i9 a prDc~ss for the prDduction of a
synthesis-gas (US, A, 4~331182) comprising the use, in the
first stage Df a preliminary adiabatic steam cDnversiDn,
Df a steam-hydrocarbDn mixture at a temperature Df 440-510C
to a temperature of 400-500C under a pressure within the
range of frDm 1 tD 30 kg/cmC~ the use Df steam refDrming
in the secDnd sba~e of the prDcess effected at the accDunt
f tbe heat Df the fuel gas at a temperatura Df ~rom 400-500
tD 750-850C and, later on, in the third stage Df cDnversion ~-
with air at a tempeiature Df the converted gas at the outlet
frDm the third stage Df 920-1?050C. ~his prDcess has an
advanbage residing in a ~higher e~ficiency of utilization - ;
f the catalyst of the primary rafDrming which enables its
use in a smaller vDlume (the primary conversiDn stage).
However, this process is eff~cted at the stage of a prs~
liminary adiabatic steam cDnversiDn under nDn-Dptimal tempe-
rature condition9j especially in t~he case Df u9ing natural
gas as ths starting hydrDcarbDn feedstDck which results
in a lDwer degree of convsrsion Df msthane in ths starting
hydrocarbDn feedstDck and in a grsater volums Df the ca~
talyst smplDysd in the stage Df ths primary cDnversion.~ -
KnDwn in the art is~a prDcsss for prDducing a hydrDgsn~
contalning gas (~ , 106076, A) cDmprising mixing of the
hydrDcarbDn feed wl~h sbeam, s9paratiDn D~ the c~mmDn flDW ' S;`
into two part9~one of which is subjected ~o the ~lrst stage ,;`~
of a stsam catalytical c~nversion and thsn passed to ths~ '
sscDnd stage of a stsam catalytlcal conversi~n, whersinto
æ~2~7~ ~
,, ~
~ -5- ;~
,'d ~, ' '.
''`t~
i the s~ccnd part of the initial steam-hydrocarb~n flow is
als~ fed. ~he prDeass Df c~nversiDn in the seeond staga
¦ is ef~ected with the formation of the desired product at a ; -
~ temperature within the range o~ ~rDm 920 bD 1jO50C with
¦~ a ~urther use o~ the heat D~ this prDduct for an indirect
heating Df said part Df the cDmmon flow of the initial
hydrDcarbon feadstoek in the steam-cDnversiDn stage. ~;
~his process envi9ages csrrying-Dut the steam con- - `
version of the hydr~carbDn feedstDck under a pressure within
the range of from 25 tD 50 bar and at a temperature at -
3~ the beginning of the process ~ from 450 tD 700C at a mass
. . ~ ..
ratio of sbeam tD the hy.lr~carbDn equal to 2.5-4.5:1 on a
nickel catalyst and at ~80-790C at the end Df the steam
conversion. ~ha secDndary cDnversion is earried out while
supplying a stream o~ proc9ss air heated to a temperature -~
ran~ing ~rom 700 tD~900C in an amDunt ensuring temperature - `~
o~ ~rom 850 ~D 1,000C at the Dutlet I~r~m the secondary
eonverqion stage.
his process makes it pDssible to obtain a hydrogan~
eDntaining gas with a ratiD o~ (H2+C0)/N2=1.9 which is as-
socla~ed with a considerable cDnsumption D~ snergy;for
eompression of the axeessive air and with a 1DSS Df a pDr- ; `,~
tion of the hydrocarbon feedstDck upon reactiDn w}th Dxygsn
D~ said excessive air.
, ., ~ .; ..
' ~
,.. ,.,. i~.. ... . .
~ i ~
2 ~ 2 ~ ~ l L ~
Ib is an Dbjecb of ths present invsntion tD prDvide a
1 prDcess fDr the productiDn of a hydrogsn-cDntaining ga~
a which wDuld make it possible tD lower power con~umptiDn fDr
~ 1ts carrying out and to reduce rates of consumptiDn of the
i~ reagents.
j It is anothsr Dbject of th~ present invention tD provide
a prDcess for the production of~a hydrogen-c~ntaining gas
which wDuld make it possible to reduce cDnsumption ~f the ~
r~eagents for the manufacture of the desired prDduct, whils ~ -
ensuring a stabl~ composition of the gas. ~ ~
. .,,,;,
hsse Db;jects are accDmplish~d b~y that in a prDcess ~ `~
for the prDductiDn Df a hydrDgen-containing gas cDmprising ,',!,'.'~
mixing Df a hydro:carbo~n fsedstDck with steam, a prsliminary
: catalytica1 steam cDnvsr~siDn of bhs resulting m1xture, a pri- -.
.~ mary catalytical stsam cDnvsrsi~on and a subssquènt sscondary
sbsam-Dxyesn cabalytical convers1Dn with bhe supp1y Df an : `
~ oxygen-cDntaining gas~th~rs~tD at à temperaburs of:not mDrs
;~ tban 900C to givs bhe desirsd~product, del1vering the
latber to the primary;cDnvsrsiDn~to carry Dub a~prDcsss
f~a~steam conversiDn by ths~hsat ~rDm the d~=sir=d: product, :
:acci~rding tD the~p~r=~=~nt i~nv=ntiDn,~ ths Dxyg=n-cDnbaining
: ; gas~supplied to ths s~condary convsrsion is mixed9 pri~r ~ :;
; to hsating, with a heat-tran~fsr agsnt in a volums ratio `,-.,
b=tw=sn~th=~hsat-tran=f=r~ae=nt and Dxyesn squa~l to 0.5:30Ø
owin~ to~th= pr===nb inv~ntion it has b~com= possible
`~ to r=duca thc rat= Df~DDnsumption Df the oxyeen-containing `~
~ . , .
- æ ~
-7~
gas and, henca, to lower the .rata of alectric power consump-
biDn for its prcparation, as well as tD reduce tha rate ~ ~ :
Df the bydrDcarbDns reacting witb the oxygen-containing ~::
gas in the stage Df the secDndary steam-Dxygen converYion.
The total rcduction of bha power consumption, as compared
to ths prior art prDcess (EP, 106076, A) i9 aqual tD
0.6 GJ/t NH
In accDrdanca with the present inventiDn, it is advi~
sable to use staam and~Dr carbDn:dioxide as the heat-transfer .~`-``.
agant which is acDnomically afficiant; carbon diDxida also
facilitatas shifting o~ the thermDdynamic equilibrium Df the
secDndary cDnv~ers1Dn towards the for:matiDn of carbon mDnoxide
and lmprovas guality of the~d~esire`d:prDduct intended for tha
manuf3ctura of alcohDl characterizà~d by the parametar Df
bhe~ratiD H~/C0.
For: sbabLlizatiDn Df the temperature cDnditiDns Df the .
procas= o~ thc primary~cDnver=iDn and, henoa, for ehsuring
stabLliby of tha second=ry cDnversi~Dn, it is advi=abl=j :
acoording bo~tb= pre=enb inue~ntiDn,~tD take 0.1-2.0 VDl~
~::`of the oxygsn-cDntainitlg:gas of:it~=:tDtal amount and- mix
it with:the desired prDduct,:prior t~o~mixlng; with th= he=t~
tran=fer agenb, priDr to deliver`ing said desired prDduct to
the primary cDnversion.
~,
o lDwer the~cDn=umption of the oxyg=n-c~nta}ning:gas: :
: in the sacondary cDnversiDn and to~imprDve efficiency DI
the catalyst use, in accDrdance with the present inventiDn
~`it lS =dvisable th=t th= preliminary steam catalytlcal con~
.
7 ~t ~
~ -8-
- versiDn bs cDnducted at an initial temparatura D~ 540-570C.
.,
~ Further Dbjects and advantages of the present invention ~ ~-
.~ will nDw bacDma mora fully apparent frDm tha fDllowing
detail~d d~scription of the process for prDducing a hydrDgan~
d containing gas and from sxamples illustrating particular embD-
;il diments D~ this prDcess.
~i The procsss fDr prDducing a hydrogen-cDntaining gas
according tD tbe presant invention is based Dn tbe msthDd Df ~ : :
~: a twD-stsp steam-Dxygsn catalytical cDnversiDn. `
~he process accDrding tD the present inventiDn is bassd
on the uss, as ths starting feedstDck, Df such hydrocarbDn ~ -.
materials as, fDr axample, methans, ethane, prDpans and mixtu-
r~ss tbsreDf; bigher hydrDcarbDns which under nDrmal cDndi~
~:~ tiDns are in a gassDus Dr liquid state. .`.-
3 ~ In acc~rdancs wlth the procsss of the pressnt invsn~
tiDn said hydrDcarb~n fssdstDck~ prsferably compressed tD a
pressure Df fr~m 1 tD 100 bar and having tamperaturs Df ~00C .
: is mixed with 9team in amounts ensuring the ratiD Df H20/C
equal to 2.5-4'1. Ths temperature Df steam in thls case is ~`
equal to 380C. Aft9~ intermixing the resulting gas-steam ~ ~ ;
mlxture has the temperature af~abDut 390C
In accDrdance wi~h the present inventiDn9 the resulting - ;
~` steam-gas mixture is heated tD a temperature within the
range~ Df from 48Q t~ 570C, preferably tD 540-570C, and sub~
: jected tD a preliminary st~am catalytical cDnvarsiDn using,
~ : fDr example7 a nickel Dr nickel-c~balt catalystO The prDcess ~. .i : Df the preliminary steam cDnversiDn is adiabatic and e~
. ~
, ' . ' '
-9~
fec~ed ab ths accDunt Df the physical heat of the staam~
gas mixture tD a temperature Df ~rom 440 tD 510C, preferably
tD a temperliture o~ from 470 tD 480C. `~
.,~ . .,:
~ he heating Df the starting steam-gas mixture to a tem-
perature preferably equal tD 540-570C is e~plainsd by the
;~ i~act that at a tamperaturs belDw 540C under condibiDns of
an adiabatic process it is necessary tD usa grsater vDlumes
f the catalyst.
he admission, tD tha stage Df the prsliminary steam
~` c~nversiDn, Qf tbe steam-gas mixture at a temparature Df ~i
above 570C causas cracking Df higher hydrDcarbons resulting ,. ,,,~,,,;,!.j~ ~ in the formation Df carbDn black.
;~ 3he use, in the preliminary cDnversion, of the steam-
gas mixture with a temperature of 540-570C makas It pDs-
sibIe tD increase the efficiency of reactin~ Df thà compDnents `~
and to lDwsr, tharsby, the cDnverted ~as tsmperature after ~`
the preliminary cDnversiDn which upDn a f urther primary
catalybical conversiDn anebl~es reduction Df cD~nsumpbiDn Df
`~ the D}~ygen-cDntaining gas. A hi8her de~;ree of conversion
~ Df the starting hydr~ocarbon-cDntaining I`eedstDck make~ it
;~ pDssible to daliver, to a subsequent prilnary catalytical ; -~
cDnversiDn, a~prDduct -~vith an increased content Df hydrDgen,
thus favouring an încreased afficiency Df the emplcyed cata~ ;
3~
lyst~and enabling the use Df smallar volumss of the lajtter~
,3~ After 9aid preliminary conversiDn the partly convarted
gas with a tempera~-ure of 440-510C is subjected to a primary
steam oatalytical cDnversion by elavating tamperature of the
-10~
....
reactiDn gas to 650-850Co The steam cDnversiDn in this
case is effected according to an andothermal r~actiDn using
a conventiQnal, e.g. nickel, catalyst. The reactiDn gas with ~ -
the temperature Df 650-850C is subjected to a secondary
steam catalytical cDnvelsi~n in the prasence Df an Dxygen-
cDntaining gas. The Dxygen-cDntaining gas supplied to the
secondary conv~rsion has a tempbrature o~ not mDre than 900C.
In acc~rdance with the present inventiDn, the Dxygen-cDn-
taining ~as is mixed with the heat-transfer agant, priDr tD . `
heating bo said temperature, in a vDlume~ratio bebwesr. bhe
heat-transfer agent and o~ygan equal tD 0.5:30Ø
Tbe upper llmi~t (30.0) Df~tbe abDve-speolfi6d vDlume
ratio is defined by tbe cDnditiDns of preparation o~ the de- ? ``
sired product intended f~r use in bhe producbiDn~f a~mDnia
wh~re`air is us~d as th~ Dxygen-containing gas. In this ca9
the obtained desired product has the stoichiDmetric ratio
of H2:N=3
~ be lDwer~limlt (0.5) Df said vDlume ratiD is defined ~
by the requirement Df a safe character D~ the process exclu-
ding break-t~hrough~oP oxygen.
As an inert heat-tra~nsfer agent the oxygen-cDntaining
gas incDrporates, for~example, steam, carbDn dlDxlde, nitro~
gen, argon. According tD the present~invention, lt is pre~
ferable~to~use steam and/or càrbD~n diDxide as~the heat~
transfer agent.
owing tD the use o~lsteam, pDwer consumptiDn for
oompression of an inerb heat-trans~er agent are rcduced,
; ~
since in this case a lDw-temperature heat can be used and
the supply Df the heat-~ransfer agent can be effected by
way ~f saturatiDn of the Dxygen~cDntaining gas. Thc US9 `.`.``~,
of st~am as bhe haat-transfer agent enables the usa of oxygen
heated to 900C in the prDcess, whereas in tha cas0 of ab-
sence of the heat-trans~ar a~ent in the reacting zone Df
oxygen with the ga9 after the primary cDnversion th3 process
is substantially n~n-realizabla due tD a high tamperatura
in said zDne. ~he use o-~ carbDn di~xida makes it pDssible
tD imprDve the ratio H2/C0 in the deslred prDduct (which
is an important indicatDr of the desirad producb quality) in i`
bhe case of the productiDn of a hydrogen-containing gas fDr ~ -
`~ the preparatiDn of methanDl and higher alcDhols. `
;~ In accordance with an ambodiment Df the prasent in-
vantion, priDr to intermixin~ with said heat-trans~ar agant ~;
bhe D~y~en-containing bas ~ox~en or air) in~n amount o~ 0.1-
2.0~o by volume o~ its total amDunt i9 remDved and mixed `~ ^
with bhe desired ~rDduct Dbtained as e rasult o~ the secondary ~ -
; oatalytioal converslDn of the reaction gas havlng Its tampe-
~ rature within the range of ~rom 950 to 1,050C. ~he major
3~ ~ portiDn of the o~ygen-containing gas aftsr mi~ing thareof
wlth tha heat-brans~ar agent is~daliverad tD bhe sccondary
c~atalytical conversiDn as it has baen msntiDned hereinabove.
he Dxygan-cDntaining ga9 mixed with the dasirad product
is dellvered tD~bhe pri~lary cDnversion ~Dr carrying out the
steam cDnversion process by the haab o~ the desired prDduct. -~
~J ~
7 ~
!~ --12--
.'~.'-~, ' .
Th~ desired prDduct temperature due to the supply Df tha ~ . .
~ygen-cDntaining gas intD the desired prDduct is maintained `- `:
. ~ . . ~
cDnstant and by 20-30C higher than after ths secDndary - ~ -
cDnversiDn. ~he dasirad producb at this temperaburs is fed
to the prirnary cDnvarsiDh whersin ib is cDDlsd tD a bemperatura ~- -
of frDm 500 tD 700C, prafarably tD 500-600C.
Owing tD the supply DI bhe Dxygen-cDntaining gas int
.. ~.. .
the desired product formed in the sec~Dndary cDnversiDn the
i ~ ~ temperature cDnditi~ns DI the first-staga conversiDn process `
are stabilized, whereby stability Df DperatiDn and Df th9 - .
'~ ~ process ~f said sacondary conversiDn is ensurad, since the "~
gas compDsibiDn after ths primary cDnversion is stabilized ~ . -
ab ths inlet tD tha secDndary conversiDn stage.
~; Ths proc~ss IDr prDducing a hydrDgen-cDntaining ga~
aecDrding to bhe present invsntiDn makes it pDssible bD Dbtain
~: a nitrogen-hydrDgen mixture either dirsctly suibable fDr tha
synbhesi3 Df ammDnia, or a nitrogen-hydrDgen mixture of the .
stoichiDmetrie co~np~sition emplDyad in the synthesis ~f amm
nia In a low-temperature separation~ ~r recDvery Df excessiva
nitrDgen under bhe most effici~nt (~rDm the ecDnDmic stand~
pDint) process conditiDns. FurthermDra, the process accarding
tD the present invention makes it pDssible to obtain :a synthe~
sis--gas ~or th~ prod uctiDn cf alcDhDls Df a broad specbrum
with an optimal ratlD Df~ H2/CO. ~ha proceas aceDrding to the .
`~ present inventiDn makas it possible tD lDwsr pDwer cDnsumption
i n b he pr od uc b i D n Df a mmD nia by 0 . 5-5 . 0%,
7 ~ 3 ~: ~
-13-
For a better understanding D~ the present invention,
some speci~ic examples illustrating it ` particular embDdi ..
ments arc given herainbelDw. ;.
Example 1 .-
Natural gas D~ the ~DllDwing compDsition CH4=92.8%,
C2H6_3,9~o~ C7H8=1~1~o~ C4H1o=0~5%, N2=1.6%, C0=0.1% and supplied :;`
under ths pressure of 4~3 MPa was mixad witb staam in ths
ratiD D~ st~am:hydrocarbDn =3:1, heated to the tamperatur~
o~ 570C and supplied to the stage of the primary steam
conversion~ where~rDm it was withdrawn at the temperature -~
of' 713C and with the content Df CH4 in the dry cDnverted
gas Df 26.6%; the degree Df cDnversion of metbans at the
sbage of the primar~ conversion being ~qual to 32~o~ ~he con~
verted gas a~ter the stage of the prlmary steam conv~rsion ;~
was fed to the stage of the secondary steam-oxygen cDnvarsion. ~ :
Also ~ed thereto was a steam-air mlxture heated to the tem-
perature Df 900'C with the ratio o~ H20/02=0.5.
~he desired product temperature at the outlet of the .
qecondary steam-oxygen cDnversion stage was 970C, the cDntent
o~ methane - 0.53% and the ratio (H2+C0)/N2=2.08. A~ter the
tage of the secondary conversion the dasired product was
delivered to the stage o~ the primary conversion, wherein
it was cDoled to the temperature o~ 620C giving its heat .~
to the endothermal steam conversion of methane Dccurring at ::
this stage.
xample 2 :.
Natural gas o~ th0 following composition: CH4=92.8%,
J ' , .~:
.:,.: .'- :, , :~ ' '
:~',',.~ ' ' ,, ,
,'~,,.',i: ': ~' . .
` l
2 ~ 7 ~
~ -14~
;~ ~
2 6 3 9%~ C3H8 1.1%, C4H1~=0-5~o~ N2=1 6%~ C2- 1% und~
th~. pressure of 4.3 MPa was mixed with sbeam in bhe rabiD
Df 3.5:1, heated to the bempsratiure of 570C and supplied . .,".
tD the sbags of the primary steam cDnversion, where~rDm :-,.',,.. :'.. ~'
ib was wibhdrawn at the temperature Df 840C and with '-'-.'.
the cDntent of metihane Df 9.0~0, bhs degree Df cDnversiDn ',':"~''',
f m=thane at the stage Df the yrimary cDnvsrsiDn being 57~0. ,.,.
he cDnverted gas after bhe sbage Df the primary steam con~
version was supplied tD the stage of the secondary steam- ~`
oxygen conver9iDn. Al90 fed bD thi9 stage was a 5team-air mix- :.. ~
ture~with the ratio of.H20/02 ~ 30 and with the temperature ;~ ~ `
of 800C. ~he desired producb temperaturs at the outlet from . ,~.
the stage of~the secondary steam-oxygen conversion was 940C. ''-' .,'
The ratio of (H2~C0?/N2=3.1. After the stage of bhe secon- ' ''''
dary conversion the dssired product was delivered bo bhe ., :;.' `.
stage of the primary s,beam,conversion, wherein ib was cooled .. ~`
to the temperature Df 620C giving its heab to the endDther- ,, .',.
mal conversion Df mstbane Dccurring at bhis sba~e.
Example 3 ~ '."',.
A mixtur~ of propane and butane in bhe ratio Df 2:1 res- ,'.'~.. '.
pectively under the pressure of 8.0 MPa was mixed wit~ steam
in the ratio of H20/C _3:1 and was supplied, at the tiempe~
rature o~ 500C, tD the stags Df bhe primary sbeam conversiDn,
wherefrom it was withdrawn at the ttemperature of 826C .'~
wlth the cDntenb Df meth9ne Df 17.8%.~he aDnvertad gas after '','~
the stage Df bhe primary steam:cDnversion was supplied tD the ,'.~.~.',
sta~e of bhe secondary sbeAm-oxy~en conver~ion. Al90 fed to
.... : -
j'`; l ` ` : :
!"~
! I
2 ~ 7 4 ~
-15-
this stage was an Dx~/gen-hydrDcarb~n mixture h~ated tD the
temperaturs of 5~0C and having the ratiD of C02/02=6:1. `:; ;.
How0v0r, insignificant fluctuations Df th~ paramet~rs of the :.
prDcscs str~ams result~d in vari.atiDns of tamp9raturs aft~r
the s=cDndary cDnv~rsiDn frDm 970 tD 950C, while the con-
tsnb o~ residual m~thane changed frDm 0.49 to 0. 70%. At va~
riations Df the desired product bemperature aftdr the sccon~
dary conversiDn from 970 to 950C the content D~ residual ~-
msthans and tempsrature after ths primary steam aonversion ~ -
changed: frDm 17.8 to 19.7% of CH4, while temperatur0 chang~d
from 826 to 810C~ In thus cass, when an DxyOen~containing ~.
mixture after th= =t=8e of the secDndary stsam conversiDn ~ .
was supplied into the desirsd product in an amount Df from : ~;
0.1 to 9.0% by volume, the temp9rature prior tD the
prlmary cDnv~rsion and, hencs, th3 cDmposition after tha:~
primary cDnv~rsiDn .~f~uld bs 9tabiliz0d. ``
An avsrag0 temp~r~tur= Df bh~ de=ir9d product priDr tD
the introductiDn thsrslnto of a~:smaller portlon o~ the
oxyg~n-Gontainlng gas wa~= 960C and, 3ftsr th9 admission,
970C. ~h~ cDntsnt Df resid~u=l:m=thans in the d=sir0d ~ :
product was~0.5% by volume.~After th= stage Df th~ se`condary
cDnv~rsion th~ desirsd prDduct was deiivered tD~th= stags Df :
th=~prlmary st=am co~nver=lon, wh~rcin it was.coDled to the
tempsrabure of 570C:giving its h0at to tha ~ndDbhsrmal steam
conv~rsion of methan0 occurri ng a t this stag=. ~ -;
.~ ~"''
,., i,: , , , ~, -
. "~-: . ,-:, .:. :. ., , ,: , , . ~ . :
, ~:,., ' - . . .- : ~ : . .
. , ,,~,," ~, ,;, ., , . . . . . . , ~ , .
r"S . ', :
~ -16-
~: . '', -,'.
Exa mp l s 4 . . .
Natural gas D~ the fDllDwing compDsitiDn: CH4=92.8%, ~;
2 6 3 ~ 9Yo~ C3Hg-1. 1%~ C4H10=Oo 5%~ N2=1- ~a~ C02=0- 1% und~r
the prassure of 4~3 ~a was mixed with steam in the ratiD
of stsam tD hydrocarbon -3:1, heatsd to the temperatur9
570C and fed tD the st`age D:~ an adiabatic preliminary ~-
conversiDn, whersin at the account Df a physical heab
Df the steam-gas mixture thare Dccurrad a prDcess Df a steam
conversiDn with cDoling Df the reactiDn mixture tD the t~m~
perabure Df 490QC. The gas after the praliminary cDnversiDn
had the fDllDWillg CDlllpDSitiDtl: C0=0~07~o~ C02=2-50%~ H2=9.32%~
CH = 22.21%, H20 = 65~o by vDlume, N2=0.90%. ~`
he ga9 aftsr the praliminary conversion was delivared ~ `
tD the stags Df the primary steam convarsion, wharefrom it `~ ~`
was withdrawn at the temp~laturs Df 754C and with the con-
tent of CH4 in the dry converted gas equal to 21.20~o. The
cDnverted gas after the 9tage Df the primary steam cDnversion
was d~liverad to the stage Df the secDndary steam-oxygen
cDnversiDn. Fed to the same stage was alSD a steam-air mix- ;~
tura heatad to the~temp~rature Df 500C and havlng the
H20/02 ratio 0qual tD 0.5.~The de9ired prDduct t~mparature ~
at the outlet from tha secDndary 9team ~x,ygen cDnvsrsiDn ~ ~`
``~ `stage~ was 970C, tha cDntent of msthane ~,las 0.5~0~and th~
ratlo ~H2+C0)~/N2=2.08. After ths stage of tne secDndary
conversion the desired product was delivered to the~stag~
of tha~primarg 9team cDrlversiDn, wherein it wa9 coDled
bo the tempsrature Dfi 540C giving its heat bD the endothermal r
steam conversiDn Df msthane.
~ . ,, ,.. .. . ~. :. : . : . :
2 !~ 2 ~ 7 4 ~
17-
~ Example 5 .``~ The starting steam-hydrocarbQn mixture of ~xample 4
~; was heated tD tha t3mp~raturs of 540C and deliv3red to tha ~stage Df an adiabatic prsliminary conversion, whsrain a~ ~-
prDcess of stsam cQnvsrsion with cDoling zf the reacting mix~
tur~ tD the tsmp~raturs o~ 470C Dccurred due tD a physica~
; b~at Df the vapDur-gas mixtura. Ths temparatur~ of preh~3ting
f ths stsam-air mixture witb the ratiD of H20/02=0.5 was~
600C. The temperature Df tb~desirad prDduct aftex coDling : `
3 at ths sta~e Df the primary conversi~n was 540C and ths
ratio of (H2+C0)/N2=2.08. ;~ :
xample 6 `~
Nabural gas of tbe fDllDwiDg CDmpDsition CH4-92.8%,
2 6 3 9%~ C3H8~ %~ C4H1O=-5%~ N2=1 ~ 6~0~ CO _ OD 1YO under
bhe pressurs Df 4.3 MPa was mixsd wit.~ sbsam in the ratio of
steam to ths~hydrDcarbon of 4:1, hsated tD the tampsrature :.-
~; : D~ 570C and supplied tD the stage:Df an adiabatic~preliminary
:~ cDnversion, whare1n at the~accDun~b~Df a physical haat frDm
ths steam-gas mixture a~process of steam converslDn tDok
place with coDling of the rsact~ing mixture to th~ tempsratur3
of 485C. ~h~ ga:s after the preliminary cDnversiDn had the
: fDllDwing composition: C0 = 0.05yo~ C02=2.35~o1 H2=8.86%, ~;:
CH =: 17 . 55~0~ N2=0.69~o~H20 =70,5%.~he gas after the prelimi~
nary cDnversiDn was deliver:ed~ bo tb~ stage Df th~ primary ;~ `
st:eam cOnverslon, wbarefrom it was withdrawn at the bempera~
t~ure Df 760C and with bh9 oDntent of CH4=15.38~0 in the dry
converted gas. The cDnvertsd gas after the stag~ of the
,
:
2~2~7~
.
' ! -18-
~,, . ~.
primary conv~rsiDn was deliver~d to the stage of the secon-
dary steam-o~ygen conversion. A1SD fed tD this stage was ;~
- a stsam-Dx~g~n-nitrDgen mixture heated to the temperature ~-
f 750C with tha ratio o~ (N2+H20)/02=5.47, the ratiD o~
H20/02 bein~ equal bo 0.59. In the case o~ availability
;1 o~ nitrDgen under pres~ure, it was used as an additive ~-~
to thc prDcess air. ~he desired producb tamperature at - ~`
tba outlet from the stage o~ th~ sacDndary sbeam-oxygen-nit-
rogen conversiD~ was 940C, the content of methane - 0.~%, -
1~ the ratio Df (H2+C0)/N2 = 2.08.
t~ A~ter thc stage of the secondary conversion the desir=d
product was delivered to the stage of the primary steam con-
v=rsion, wber=in It wa= cooled to the temperaturs of 540~C, ;~
;~ ~ giving it= beat tD bhe endotbermal sbeam conversiDn Df me-
tbane.
' ',',' ,'. ,;
,~ ,.',,.'. ,,`
` ~ ; ' ,,j~",.,",
