Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
' WO 9411C990 2 1 3 1 9 8 7 PCT~S94/0088~
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- Tm,~e -~ :
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MET~IOD FOR REMO~XNG SUL~IDE WIT~ CATALY I IC G~RBON
LD OF T~E lN~FNllON `; ` ` ~ ` `
Thc p~sent i~lVCDtiOD ~elates tO thc USC of a higSly colybcDlly ~ c c~s char for Ihe
E~ rcmoval of sulfJdc ~om gâs~or~q~d media ~ osencc dODCygeD and~wa~cr. `' `~ :^ i
:: BACKG~OU~DOFT~IN~'ENlION ~ ~ ~
VJ~rious mc~ of rcmo~ing H~S using a~s~ re hwwo. For e~ple, 1~ ~as been
uscd for the ~emoval of hydFogcn ~ulfidc and vl~rious mn~sn~ a humidifiod, ~ng
10 gas~ous stream. ImptovemeD~s in thc~vai qrbilibe~ of ~l# C~35 ch~ hvcbccD realized by
the addi~ion of a basc~ such as ~nunonia or hydroxi~ to tbc char w~c d~g the~:mov~;psocess. It
hasbeenf~undths~ ~dditionofc~l-inhalogens~Dd~ransido~c~ali~c~schar
substratcs also the l~movd of hydioge~ nd m_ ~m ~d air ~ums. Howcvcr,
noneoftheseimplovcmu! ~edtheirhe~tplopQticsd~ ~entally
1 ~i responsible for lhe obscrvcd pbawmalon in the abscncc of promo~ wch as ~ y~idc, potassium
iodide, or othcr compuulds. : :
Some implovcments iu thc po~e ~ze distribudon of ~cdvu~ cub~s hllve beeD dcsc~ibed wherein
a high-~cm~alre cdvued cubon~ char is ~led~with ~ or mel mi~compwnd~and calcineda~high~ es. ChucFc~dinthis~m n~erhav~eD~edbyd~a~ biDdes;
20 bowever,: the ~ili~ of such chan to ~emo~c h~ u~lfidc by c~lytic <~do~ was not ~ or
~: ~eported. l~çptoductiond~c~uschar~ ~btbkf~chy~genwlfidco~cnhasbeeR~aught whclein a high-temp~#~re aeti~ bon colce i~ o~idi~d ~nd e~ed to a ni~conu~ning
ammoruum salt al tcmpo~res abo~c 3S0 C.
wog41l6g902~31987 ~ . ;; PCT/US94/00884
Such prior an methods have c~rlain disadvantages which limit ~hcir applicaioa. The usc of
commercially-availablc unimprcgnatui scdvn~cd carbons for cataly~ic hydroger1 ~utfide remova~ suffers from
low rates of aemo~ral, ~nd conscqucntly, low hydrogc~ sulfidc b~a~through c~citics. T~c u5c of promotc~s
in the p~escncc of ~2ch ~naceous ~s also entails cerlain di~advantagcs. For c~amplc, thc use of
5 ammonia roqlai~s added cost and ha~ard in thc ~ns~ion al~d co~trol ~3f measmed a~monia additio~. The
usc of sodium hydm~ide a~d o~er mc~al ul~ ~Iso iD~rolva addcd costs ~ ~ell as ~ iDc~ascd dsk of
thennal cxcursjo~ d~c to the 3Owenng of the char ignition tempcsa~e.
Accordin~ly, it is Ihe o~joct of ~hc p~e~t i~vention to p~dc ~ cut~ c~u which iscataly~ically activ~ for sulfidc and me~csptan removal in thc presencc of o~ygeD aDd water wbcl~ compased
10 to other unimprcgDated chars and ap~ *om t~se ac~ic parame~ h~own to affect ~ch removal. For
cx~mplc, c~t insic p~uamete~ ca~ includc p~ticlc size di~ributioD, po~ volumc distJibudoo, and contact
~ime. It ~s further thc object of thc p-e~ent iovendon to produce a~d employ ~uch ~onsc~s chars at
minimal cost ~nd hazard when comp~ed to pnor ar~ .
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SUMM~RY OF T~IE INVENlrlON
., I :`
Gcncrally~ the present inven~on co2np~scs the ~:moval of w~ldcs aDd mc~aptans from media
containing oxygen and watcr by thc cataly~c action ~f aubonacoous chars. l~cse c~ars arc prcparcd by
the low-tem~rc carbonization and oxitation of nit~cn p~r feedstocl~ Thc o~idizcd low-
temperature c~ar is Ihcn subjected to a nitroge~tai~ng ~p~und at high tempa~res during thc initial
~alcination or calcination/acd-ation. Ln all cascs, bightall~ c~w cha~ re those p~aduced
20 by ~hennal ~mcn~ at tempa~tures gralterthan 700 C Low ~pC~E cubonacoous ch~ are those that
havc no~ aspenenccd tempe~res ~ate~ Ihan 700 C.
The prefe~d ~trogen-~ feodstoclt i- a bi~minou~ coal or a bi~miwus co~l-lilce ma~ial such
as thosc dcrivod from higher or loweT ~nlc bi~meDs, coals. or lipoocllulo~c m~ by various ehunical
Iseatments. B~amples of higher ~ ooals include ~th~acite or scmi~ c coals, while c1samples of
25 lower ranlc coals include peatt lignitC~ and sub-bi~mi~ous oo~ls. E~amplc~ of lhe ehemieal treatment of these
fecdstocks include all~ali metal trea~mcnt of thc high ~anlt ~ial6 aDd ZiD: chloride or phosplloric æid
trcatment of thc low ~anlt matcrials. These typcs of treatmc~ts can slso be ~pplicd to lignocellulose matenals.
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WO 94116990 2 1 3 1 9 8 7 ~ ; ~/US941008~
In a prcfened embodimcnt of llbi8 iDvention, thei feedstocl~ matsrial i~ aizcd, mixcd if necessary
with small alslounts of a suitaUc binder such a~ pitch, briqucucd or o?Lherwiisci fonned, and sizcd. Thc sizcd
matcnal is ?Ihen cxtensi~dy oxidized at tcDlpcrah~rcs Ics~ ~han 700 C, prcfe~ably les?ic than 400 C. The
5 oxida~ion is continucd UDlil additioDal ga D the catalytic acti~i~ty of thc fiDal prot?ua U~c 1~0 IOlSger eviden~.
Thc oxidation i c wcll bcyond lhat ~ically required to r~s~ove lhc col~ng proper~ of bi~ coals and
pr~uces an optimally o~cidized ch~. Otl~e~ oo~vel icnt mcaD~ of o~ on c~ d60 be usod to cf~eGt thc
low-tempe~ re oxidatioG and c~bonizatio~ of thc ~K m~ s ~:
~e oxi~zcd low-tcmp~re c~ char i~ thc~ a~po~ed to ~iall ~nounl~c of ~n
10 inexpe~ciYe~ abundar~ ~d sclativcly ~-toxic nilrogc~-contai~iDg compou~d ~uch as urca du~ing, no~ ahcr,
thc initial calcination and co~on of she aubon ~ Thc amo~t~ of nilrogen-con~aiDing
compounds uscd ase typically w~all, prcfe~ably Icsc tb~ S% by wcight of thc o~idizcd b~mpc~re
carb~nacoous char`or ~uch ~ ddido~l guns i~ th~ cs~y~c ~tiv,ity Qf th~ al ~UCI `aré~no longer
cvidcnt. Thc t-eatm_ is ca~Ti~ b~i hea~ng t} o~i~ rc char to bigh temp~res,
15 ~prcferably belween 8S0 C and 9S0 C, in the p~e of t~e nilrogen~onuining comp~nd. This hc~ting is
preferably conductc~ undcr an ~mo~pherc Ibat is inert accept ~orthc ~asa and vapors atlributablc to the ch~r
andfor the nitrogcn-containing compowld. The bcasin~ e and ~p~ efe ably selccscd such
that addhional ~ns i~ the catalytic cti~iq of ~c final product l~se oo ~gcr cvidcnt. ~ ~
Thc nitrogcn~ ed high-tem~ c us cbt~r may then bc acdvated to ~hc desired
20 density at tempera~res sbove 700 C in ~tcam andfor c~bon dio~ nth or without thc addidon of otbcr
gasifying agents wch as alr. Thc calcincd or calcined/acti~ated c s char is then cooled in an
- oxygen-frce or olhe~wisc iDCrt ~Itmospberc to tempc~ Ic~s tbaD ~ C, p~fe~ably Icss thar 200 C.
Additional gains in alalylic actiYiq may bc ~lizod blr epcating t~c o~udation~ powrc lo nitrogcn-
conlaini~g compouDds~calcina~on or calcin~tionf~lctiY~ Dert coding as m~my tuncs as may bc desircd.
25 Altcrna~iYely, any o~h~ mcthod ~ to genale cataly~ic ~iviq in high tempQ~e c~ceous chars
may be applied IO the rcsultana product to fb~thar ~DhaDcc its a~talytic ~ctivity.
The cataly~c~y-utive c~ char p~d ~ocdLng to the above method is then contac~ed
with a sulfide~ontai~g media in the prescnce of watcr ant o~ygen. Sulfide is rcmoved f~om the media by
wo 941l69go2~.3 19 8~ Pcr/usg4/oo~
calalytic oxidation to primalily sulfates and clemen~l ~ ur. The o~ng tcmpuaturc is b~wecn ~1s ~1t
O C and 300 C and pseferably bcswecn about 0 C and 100 C and morc preferably b~w~en about 2S C an~ 90
C.
PRESENTLY ~FERRED EMBOD~ENTS i -
~; lheutili~o~ein~endo~isillustra~dbythefollo~qngtwoex~mple~. Incache%ample,oquivalent
mcsh sizc fmctions of thc ca~bonaceous c~s wcrc evsl~cd t4 ~cgate any particlc sizc effec~ Thc chars
used in thesc examples ha~e appFo~y the ulmc de~e~ and CCI, acdvities. Tbi~ Deat oguivalcnce
indicates that the porc volumes of both chan ue nea~ly equivalen~ Thc~eforc ~c bcncfits of ~e prescnt
i nvcntion ~rc cvidcnt as thc extrinsic propefie~ affccting clllfidc ~mt>val ue nc~rly oqui~alent for thcsc
10 samples. E~ple 1 temo ~hcH2Sremovalapaci~ofa~pcndcmesh~f~ionofacommacial
. .." -"~ actiYa~ed ca~on. Examplc 2 dcmonstr~cs the 1~2S Doval capaciq o~he invcndon. Companson of lhesc
. , .-two examples shows ~hat the perfonnance of the invendon grcady e~cceeds that of a typical acti~/atcd carbon.
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EXAMPLE 1 ~ . ~
A commerci~lly available sctivaled aubon, 8PL (~d by Cslgon CSUbOD Co~oration,
15 Pittsburgh PA~ was sizct to less than S ~ g~er than 6 mcsh (IJ.S. St ndard Serics sieYcs). When ~o sized
this carbon showed an Apparent Density ( Test Method TM-7, Calpn Carbon Cpo~ion, Pi~sburgh PA)
of OrS04 gTams per cc and a ca, Nwnber ( Tesl M~ TM-6, Calgon Cllrbon Corpo~ation, Pitlsburgh
PA ) of 55.1%. The sizcd carbon was loadcd inlo a ~lum- having ao insite diamaer of ~ppro~umately 0.73
inches to gi fe a bcd depth of 9 inchcs. Column lo ding w~ done in ~uch a manneras to achieve a packinn
2Q density cquivalent to ~c Apparcnt Dalsity. A ~as strcam ba~g ~ relativc humidity of g~er than 50~fc,
an oxygen content of g~ea~ than 17 vl~f*, and a howo H2S concenllYion of app~im~y I vh/% was
passed through this eolumn al a flow rate of 1~50 ~ ~tc und ambicn~ dîdons. The cfflucnt
from this column was monito~ nd the el~l time re~ui~d to chieve a 50 wm H2S breal~luough was
measured. For this ea~on sample the elapsed timc piod w~s equal to 9 mi~utes.
~1~198~
WO ~4116990 ^ PCT/US94/008~4
. EXAMPLE 2
Bituminous coal was pulvaized, mLl~ed with ~ut 4 tc 6% coal t.ar pitch, and briquctIcd. The
rcsul~ant briqueues were crushed and sized to producc ~ appro~imatcly less than 4 mcsh size and greatcr
than 10 mesh sizc (U.S. Slandard Se~ies devcs) maserial. ID thc prcsc~cc of largc quan~ tics of e~ccss air,
this material was o~idized by hcating from 100 C to 200 C a~ a ~ate of 200 C pcr hour, thCD from 200 C to
350 C at a rate of 100 C pa hour, then held at 3SO C for 4 ~ and fi~ally h:atcd from 3SO C to 450 C at
- a ratc of 100 C per hour. The rcsult~nt o~cidi2ed matcrial was coolod to Dear ambicnt tcmp~us~s în a low
o xygen content a~mosphere, sizcd to produce an #pp~o~atcly lc~ ~ S ~nd gteater Iban 6 mcsh ~izc (U.S.
Slandard Scrics si~res) n~serial, and ~ubscqucntl~ imprc~ with an aqueous ures soludon and dricd. Thc
10 ~uantity of urca ~oludon u~sed was sufficic~t to producc a 4% urea loading o~ a dry wcigh~ b~sis. Aftcr
impregna~ion,portionsoftheo~udized,imp~ atedlow-~paaturccharwacrapidlybcatedto950Cunder
. an incrt gas atmosphere. ~cdia~ely following this calcina~ion ~ nent thc resultant ma~erials wcre
zctivaled with stcam at 950 C for a ~uffi~c~t pcriot of timc to acbievc ~he dcsired yidd. After activation,
the materials werc coolcd ~o ambicnt ~em~ under a~ iDert ~plleYc. The catalyticaliy-aclive
15 ~ ivated ca~bonaccous chars ~o prQduccd, when combincd and dzed to less ~an S mesh (U.S. Standard
&!~ies) and greater ~ 6 mcsh (U.S. St~ Scnes) exhibitot ~n Ap~t Dcnsity ~cst Mcthod TM-
7, Calgon Car~on Colporation, Pittsburgh PA) of 0.49S g~ams per cc. Thc CC:I, Numbcr of the sizcd,
combincd chars was SS.S%.
Thc H2S rcmoval ability of thc sizcd, catal~tically-~lc~ivc, activatcd high-tcmpcraturc carbonaceous
20 char prepared as described above was ~inul using conditions idcntical to thosc describcd in Example
1. For tbis sample of catalytically-activc activatcd car'oonacoous char the elapsed time pcriod ~cquired to
achicvc a SO ppm H~S brcalcthrough was oqual to 326 minutcs.
While a prescntly prefe~ed embodiment of thc invcntion ha~ bCeD dcscribed, it may be otherwisc
cmbodied within the scopc ~f tllc appeDded claims.
