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Патент USA US2404405

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July 23, 1946. _
c. H. M_, ROBERTS
2,404,405
METHOD" FOR REMO-VIN@ IMPUBITIES FROM MINERAL OILS
_Filed Deo. 16, 1959
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2,404,405
Patented July 23, 1946
y
MErHoD‘roirREMoviNGIMPUm'rms
àmou/r1MINERAL" oil-ls
‘
L:(liand'iïlls
t, Calif., `assigne
Roberts, Palos Verdes Estates,
oÍPetrolite Corporation, Ltd.,
1
,
4 :Myi invention relatesytofthe purification Qi, ,oils
and, mores-particularly, ,to . ,al methodsând ~, appa
ratusoforremoving itvaterrdispersible @ímpllïíties ~
'A2
'
îordispersioncapable of,> continuons electricite@
ment. By this mocl'e yof,neemt1.011,1it ,ís/possible to
Se@ureal desired.,heterogeneity zei-,partitie site 0I'
Vfrom ~oi.l, :for examplefsremoving „saline-¿material
@mentsfatldifierent sequential positions@ obtain
' tlie process is l also >-applioablefto Marions y Qthßr
. oils toßremove impurities! capable` of .aheinigï taken
-uplßbyetlemadditìonof water.
»the »desired electricallyetreatakrleidispersien.
. lian,attemptismadeto addetneientireemount
,of water`r at .a Asingle«_povsitíîori,Lîfollmveçlxbyi @mix
Y
»It .is ¿not «uncommon Jto „find oils foonft .initie
ing ¿step adapted ¿to disper f the Wate »into the
y«waterpsolulb1_el ortwaterewettable l impurities ; and, 10 oil, it will be found _ind-_nest
that ¿reaffi
>most trequentlmethese ,vare-¿present»inftlieoil1in Y, « nitely ¿limitedrmiXing-faotion 4musi? be used; if gthe
the form of, or associated-mth, y.Sina-l1 \_;liqu_id
droplets )oresolidf iparticles ¿dispersed orsemulsiñed
throughoutftheeoil, ‘thong-hún some instances
„process is to :be ¿capable ofoontinuouslyâvresolving
the emulsion or dispersion intoçtoilzandewater,
-- without @the ‘accumulation »of » such:` amount of
sludgesasçwould,interfere.iwithsthermaintenançe
tlieyr‘maylbe in. solution j.in- ~thef-oil,;;asf in; theqease
ofrvoertain-inorganic acids whichare soluble Íboth
Íin oil «and «.Water. Such‘irnpurities `are@herein
lsiralolejnv,many?,instanoesàto haven-prese
«termed «as
y.dispersion droplets 4_4 of ,added water
“Nvaterfdispersi-ole impurities,” ¿by
»wlflich.=term»1.»have reieren’oel to impurities which
a quite ¿smallin L_size, » often'. eommensura , „Y
may -4 »be ldisperse‘di in :wa-ter,- = either ato , produce .a 20 with l thel dispersed limpuritns `which a; some
A-tiniesëpr‘esente-«in iaisize; of about: l, mu. Igfffthe en
homogeneous isolution , (as,- inflthe Ycase ¿of Water- -
Y» tire ¿amountu of iwater .ist added ;;at:y a .Asingleposi
soluble Limpurities »which ‘are- miseible with «or
"tionpitßiis rs'ometimesìffound' that ¿an` ,electrically
- so'lulolel in, the i Awater and which, ¿when 4¿dissolyed
in» «Wa/ter, « mayfsbe regarded asimolecularly -or ion
:untreatable emulsion- on dispersion: results if suffi
~ finally/:dispersed therein) „forte produce-a Water 251. ‘oieiitëmßixing action is)appliedftoiinsureîthat some
of the: added ¿Water i is .dispersed in; .particles ¿of
~ continuous dispersion-including the impurity ¿as
¿such smalllsize. rlúkewise, While/someV degree'> of
theint‘ernalf piiasei (as ».in; the , casefof Water-Wet
i lla'eterogeneityïof L=partiole1size of -thezaddediwater
table, Iwater'-insolublelimpurities) .
can « be obtained. by l an „appropriate-singleemixing
The removalof wateresoluble or` `water--iizettable
impurities¿ifromtsuoh boils 'ßisia problem which „is 30 step, therange ofëyparti'oleisizes isz's‘onleti-rnes con
A„siderably » lbelow` that »Lwfiiiohz` is amostg-` desirable; yin
-i'rïequently en countered; and-„Which - is 'grof ¿particu
lar importance in'j thef handling: oflp'etroleum'goils,
-~tb1e».pro`oess. .'Gnx some Voils-¿tine rangeof particle
>size@appears 'quite small ‘iflsucli singlefstepç‘mi-x
ingßae'ltionßisîusednasiwilt remove ¿the desiredïpro
as dispersedisa‘lt«orgoileíieldA brinçgand „also ¿in the
removalßoff reagentsiand reaetiontproduots in re 35 portionmof tlie' impurities.
The dispersedpand frequently
`very-i'loi’glnly> stabilize`d,‘- condition ofthe impurities
crudeAv or topped, A containing salinel Jiriaterial,l such
>.makes -it ydifficult ,orf impossible tofaeoomplish- the
< desired »purification by :ordinary nonißlecßl‘ìßal
methods.
lAccording to the p-resentaprocess, 'suoli> impuri
ties are `removed-Joy forming/in; anovel manner,
an artificial dispersionfìor -emulsionfwhioh _isV oil
continuous ,and ,which> includes dispersed Water
„droplets of different sizes~ or;l addedfunder `differ
ent conditions, this dispersion .being .- treated
electrically ¿to coalesce the water which, 'when
separated, is found to contain most of the Water
L110W#»through a t restricted ¿ori'flc-ze, ¿a l¿more ‘Jorl less
»heterogeneous « partiel'e‘JsliZe ¿distributionY »may @be
40 l, obtained;
in »Wilicrhl tlie-v particles ~ varyî‘frorn; small
--to large LWli-th a- <sing-le‘-predominant-size,ltl'ieiis?ize
Y- f requ en_cy distrib-¿tion ollowing~~theß=welléknown
probability `curve with asin’g-le -In-ax-iinumatsoine
intermediate size depending upon the adjustment
of :the «'dispersing ‘means @When the Water is
'added *4i-n- f-two increments, ¿the ` E'first j _to ~`produce
particles ~ of esmalleriayerage size; than - `_are Vjlpi'o
f_duçed inlthe'ësecond'fmixingstage@ thefelia ‘ " 'tér
dispersible impurities, and it is an object of the
listieL particle -~size çdistributionfcurve is~seouredjfor
present invention to provide a~novel `method op 50V yeafelfrïiiicrement,¿ykflài-le the-"final resultant-ldispèr
erating in:A this manner.
'
It is another object of the invention to,v intro
¿duce theadded water into the system Vata'plu
r'ality of‘points, dispensing the ‘Water lntothe oil
in a manner Well< suited 'to pro-duce ‘anjemulsion
' ' Sion »contains particles-»showing two
.
.
aix
‘ima inthe size‘ëfrequerrcy distribution'curve ‘or
-resporiding-tò the'adjustment-titte two dispers
à
4
than a small amount of water, usually under about
8% and only very infrequently as high as 10-15%.
Best purification results are obtained by starting
with those of the impurities inthe oil in any def
sired ratio to those of the larger sizes, thereby
permitting great flexibility in adjustment of the
treatability of the final dispersion, together with
ability to obtain an increased degree of removal
of the highly dispersed impurities; whereas, when
using a single dispersing step, it may be'possible
to secure enoughparticles of the desired small
with an oil containing Ano more than a few per
cent of water, for example, an oil containing from
¿a fraction of 1% up to :5f8% ,and Ihavea decided
preference »for oils inthe-lower' portion of this
range if a high percentage of the impurities is to
size only at the expense of'obtaining too lowv` a '
» be removed.
l Thewater which I disperse sequentially into
concentration of particles of the desired larger
sizes, thereby leading to .difficultiesV in theV sub- K'
the oil’preparatory to electric treatment should
sequent electrical resolution due to formation of
be relatively fresh, by which term I have refer
sludge.
,
Y,
,
ence to water capable of taking up, or becoming
.
It is an Vobject of the present invention to pro-V
duce an electrically-treatable dispersion vrof de
sired heterogeneity as to the size of `dispersed
water droplets therein.
It is another object ofthe present invention to ‘ `
add water to the system at two or more points
vvassociated with, the Water-dispersible impurities
to ‘be removed. This relatively fresh water need
not be distilled Water and need not be entirely
devoid of the impurities to be removed or other
chemicals or minerals, and, in fact, the process
is improved on certain oils by the presence of
separated by one or »more mixing zones in which 20 `small amounts of chemicals, as disclosed in cer
a controlled mixing action is applied.
~
‘ `
~ Another object of the present invention is to
disperse a portion of the added Water into the
oil in theform »of relatively small droplets, and
to disperse another portion of the added water
into the oil at a later time, the later-added water
tain copending applications, for example Nees,
et al., Serial No. 312,745,5now Patent No. 2,380,458:
It is imperative, however, that if the incoming
yoil contains dispersed impurity-containing drop
25 lets, the added relatively-fresh Water should con
tain- these impurities, Vif at all, in concentrationsY `
being present in the form of droplets which are _
materially lower thanthe originally-present drop
lets, and if the oil' contains no such original droplets, the `relatively fresh water should have a»
« -Further objects vand advantages of the inven-, 30 concentration, if any, in the impurities to be re
moved Which is very lovv.«A
.
'
tion will be made evident hereinafterto those
Y Ineiïeclgrthe process adds droplets of relative
skilled-in the art.
~
‘
Vly fresh water tothe Voil in controlled dispersing
A The process is particularly adapted to the puri
fication of oils prior to subsequent refining steps; ` steps so that .the electric ñeld can coalesce the
for example subjection to distillation or crack 35 dispersed Water and exertïa powerful action mov
of anl average size larger than those produced
inthe first dispersingfprocess.
-
ing temperatures. »It is capable of taking out,
-and particularly applicable to the removal of,
-impurities which, upon heating. to refining or
cracking temperatures, comprise lor form acids?
ing theiinpurities into the relatively fresh wa
ter. Following separation of the coalesced wa
ter, the oilwill usually >still contain certain dis
persed water droplets present in amount not more
or other materials-having a tendency to corrode 40 than a few percent, andpreierably less than
f or form deposits in the subsequent refining equip
v nient, or having a tendency to deleteriously af
fect the quality of the final products. Purifica
tion by the present process makes possible longîzì
`trouble-free runs on such subsequent equipment,
and they process can well be operated to be main
2%, but such dispersed water will correspond
predominantly tothe added relatively fresh wa
ter, and theY water content is made low enough
so as not to be objectionabler in subsequent _re
ñning steps, if used. The necessity forvuseof a '
-relatively fresh> water. will be readily apparent
tainedon-stream with this subsequent reñning
from an example assuming the presence of 1%
equipment with no appreciable loss of oil.Y On
of brine> in the incoming oil andthe presence
the other hand, the process is not limited to the f, >of A1% of water in the oil resulting after sep
treatmentof oils preparatory to further refining. 50 aration of the coalesced water. If this >incom
The oil with which the presentinvention is Y ing oil contained 100 pounds ofÍsalts per _1000
concerned _can be any oil having suñîcient re
barrels of oil, these saltsbeing, for instance, pre
sistivity to sustain an electric field at coalescing
Y dominantly magnesium and calcium chloride, and
potential when this oil is present in Whole or in ,
" if the added water is of the saine concentration
part as the continuous phase of an emulsion or
in these impurities as are the original water
dispersion in which the added Water is dispersed
in accordance with theinvention. Petroleum oils
salts in amount about 100 pounds per 1000 bar
Y are particularly well adapted for treatment by
the process, whether in a crude state or Whether
vresulting from previous refining steps. In the
>latter connection, the process can be used on
topped`oils or on various fractions obtained from
oils.
-
Such oils can be dry, or substantially dry, or.
droplets, then the separated oil will contain these
rels, and the total reduction in the> impurities willVV
be negligible. -On the other hand, when operat
ing with a relatively fresh water under the same
circumstances, reductions in salt content of more
than 90% can be readily'obtained.
The electric field /utilized'in the process should
be capable of bringing into combination or asso
can contain dispersed water with which atleast 65 ciation the impurities and the droplets of rela
some of the impurities may be associated,_this
tively fresh water, and should, likewise, be capa
. Water being dispersed Vin the oil to form what is
hereinafter. termed “original Water droplets.”
.e The?process is not well »adapted to oilsl of -high _
ble ‘of coalescing the water into masses of sulfi
' cient size to be readily separable from the oil.`
The eoalescing iields herein-used are usually of
water' content, for example,` oils containing from 70 the
high-Voltage alternating current type, though
¿20%, to‘50% of Water (percentages here and else
coalescing iieldsformed'by the use of directeur
where are by volume), and such oils are prefer
rent can, in some instancesybe substituted, though
ably first dehydrated to produce the starting ma
terial for the4 present purification process. The l the> 'process is 'not concernedwith low-voltage
preferred oils are -those which contain no more rá fields exerting only a cataphoretic action', `Í “ ' "
2,404,405
adjustable weightY 4 l! so» that. the'l mixing. action
The process can best bedescribed with refer
ence to they treatment of mineral oils containing
may be adjusted by moving the. weight. 41..
water-dispersibleV impurities, and the» process
hereinafter described will be exemplifiedA in this
manner, without intention of limitation. '
'
Thedispersion thusA formed.Í is shown asamoving
along the pipe. 231 to. ajunctio'n. 44 under the ac.
tion ofI the pumps-21' andl 261, Hera, the second
portion of relatively fresh water isv injected
through» a pipe 45' after'being- suitably heated, if
desired,'in» a heatexchanger 4t.. This relatively
fresh water is moved into the pipe 45= through a
'
Likewise, appropriate apparatus willbe shown
as- exemplary, and inthe accompanying drawing:
Figure 1 illustrates diagrammatically one em
bodiment of the appara-tus capable» of carrying
10 valve 45a therein by a pump 4l intaking from a
out the process;V
second- tank 48.
some instances, a simple in
Figure 2 is an enlarged view in vertical section
jection of the second portion> of water int-oi the
of one type of mixing means useful in the process;
oil streamv will mix the! two and give a .desired
Figure 3 is an enlarged sectional View ofr a por
type of dispersion- containing, for examplavsmall1`
tion of the electrode structure shown in Figure 1;
and
`
-
15 droplets of relatively fresh water as dispersed into
the oil by the'rirst mixing or dispersing step, and
larger droplets of‘rel'atively fresh water dispersed
into the stream“ by the injecting- action- adjacent
Figure 4 is an enlarged sectional view of the
distributing means shown'in the‘ele'ctric treater
of Figure 1.
n
y
Referring particularly to-Figure l1, theÁ oil' to be
the junction 4'4". v However., in many» instances, it
treated may'be moved through pipe> >I El by a pump 20 is desirable to mix the constituents further and a
mixing means 5Fl can be used in- this connection.
I I. If this oil is already of low water content, it
This mixing means is shown as comprising a
can be discharged through pipe l2 and 'valve I3weight-loaded valve V5i ` similar to that previously
into a tankv I4. If the water content ofthe oil is
described. The resulting dispersion is delivered
high, it is preferable first to dehydrate the oil'V by
electricaL‘chemical, centrifugal, or other means, 25 to the electric treater but, if desired, can be addi
tionally heated or cooled by use» of a heat ex
or merely by settling. This can be accomplished
by opening a valve l5 so4 that theincoming `oil
moves to a dehydrator l5 from which the excess
changer 53,
2|, which usually supplies suflicient pressure to
into the pipe 23 in proportioned amount, this
'
A valuable adjunct to the process and appara
water can be withdrawn through a pipe’ I‘1, >and
tus thus far described, and which can be used in
the oil of low water contentv through the pipeV |'8 30 place of or to supplement the dispersion of the
i'lrst portion of the relatively fresh water inthe
for delivery to the tank I4.
‘ "
The oil to be purified is withdrawn from the
oil, is the addition of vsteam to assist in the forma
tank i4 through a pipe 20 by the action of a pump
tion of the desired dispersion. If steamv is moved
move the oil through the system while 'main 35 steam will be dispersed throughout the oil stream
taining superatmospheric pressurev on the oi'l
and> will almost instantaneously condense: ‘De
pending upon the manner of injection of the
until' it discharges from the electric’ treater. If
desired, the oil flowing in the pipe 20 may be
steam, particles ofv relatively fresh water of> dif
heated by passagethrough a heat exchanger 22
ferent size can be thus dispersed, the relatively
and then flow along a pipe 23.
40
'
Any suitable means can be used for dispersing
relatively fresh water into this oil in two or more
fresh Water in this instance comprising the con- À
, densate. Usually, such dispersed droplets formed
by the injection of steam are quite small in size,
positions, the dispersing steps being such as to
facilitate the operation of the process, asv herein
before described. In the exemplary showing of
Figure 1, the relatively fresh Water is added in
two stages, and dispersion is effected by flow
through mixing valves. For example, the first
portion of the relatively fresh water may be sup
plied through a pipe 24 to a tank 2'5 and, from 50
this tank, proportioned into the oil stream- by
use of a pump 25, moving the water through pipe
2l and valve 27a into the oil stream vin the pipe 23
at right angles at the junction 28.` If desired, this
portion of the relatively fresh water can be’
heated in a heat-exchange means 29.
Injection of this portion of the added water
into the oil stream mixes the water with the oil
and forms a preliminary dispersion atr the junc
tion 28. However, in most instances, it is de
sirable further to mix these constituents and this
can be done by use of Aa suitable mixing meansSil
disposed in the pipe 23 beyond the junction 28.
and this is often desirable in the process.
As shown in Figure 1, steam from any suitable
source may be moved through a pipe 5,1 and,
upon opening of a valve 58, will be delivered to
the pipe 23 through V.a pipe 59. Alternatively,'or
at the same time, upon opening a Valve 60„ the
Steam may be delivered in lproportioned amount
to the pipe 23 through a pipe 6I. Correspond
ingly, steam» may be delivered either prior to or
after dispersing the ñrst portion of relatively
fresh water into the oil through the pipe 2ï.
Often, such injection of steam can be used to elim
inate the addition , of relatively fresh lwater
through the pipe 21, relying upon the later addi
tion through the pipe 45 to supply the somewhat
larger droplets of relatively fresh water which are
desirably present in the dispersion undergoing
yeo
electric treatment.
Y
l
While various electric treaters can be used in
the process, Figures 1 and 3 show an embodiment
which has been found to be very satisfactory and
This mixing means is preferably of the once
which is claimed in the application of Harold C.
through type and may well induce the desired 65 Eddy, Serial No. 218,681, now Patent No. 2,277,513.
mixing action by the turbulence attendant upon
This treater is preferably, though not necessarily,
change in direction of flow or passage through a
of the type in which electric treatment yand sep
restricted oriñce. One readily-controllable type
' aration take place in the same tank. Such a tank
of mixing means is shown in Figures 1 and 2 as
is indicated by the numeral 10, and after opera
comprising a weight-loaded valve 3l providing a 70 tion for ,al period of time, containsr bodies of oil
seat 32 in a partition 3‘3. A valve member 3d is
and water TI and 12, shown as separating at the
vertically movable toward and away from the
surface or interface '13.
v yseat 32 by use of an arm 36 pivoted at 31 to a post
38, and pivoted at 39 to a plunger 40 connected .
to the valve member,
The' arm 36 carries an "75
In view of the electrical system utilized, it is i
desirable to maintain this surface or interfacer 1.3.
at or about the position shown, and to accomplish
2,404,405
8
This type of electrode structure presents a ‘min
imum impedance to gravitational separation .in
this, therateof withdrawalof treated constitu
ents from the tank 10 may be. varied. The system
shownincludes a water draw-oiî pipe 14 equipped
the _tank 10, the rings and supporting means
therefor covering only a small fraction of the total
cross-sectional area of the tank 10. Furthermore,
the interstitial character of these electrodes'per
mits free ycommunication between the electric
terminating at its upper end with the' body of Voil
fields and facilitates rapid removal of coales’ced "
1| and being provided at a4 position near the in
water masses therefrom.
terfacial zone with a chamber 18.
`
,
The incoming dispersion or emulsion is pref
«An oil-water interface will thus form in~ this 10
erably delivered from the heat exchanger 53
chamber and any suitable means can'beused ,to
through a, pipe `| I5 directly into the lower treat
control the withdrawal from the tank 10 to main.
ingspace 98. It is preferred .to move the dis
tainV the interface 13 substantially constant in po
sition. A float19 is shown in this connection and ' Y persionrradiauy outward in this neld so thatV it
is mounted on apivoted arm 8_0, which is con 15 moves successively through vthe edge-to-edge
ñelds and sets up desirable circulations intofthe
nected by link 8|, with a link 82 forming a part
treating space 98 from the zone thereabove and
of the operating system for the valve 15. „The
from the zone therebeneath, thereby Vpermitting
float 19 is of such character as to sink inoil and
recycling of some of the treated constituents
float in water. Correspondingly, when the inter
face rises, the float moves upward and, through 20 through the electric field. Such radial discharge
may be `effected through use of a distributor IIB,
links 8| and 82, the valve 15 is opened ~suiiiciently
best shown in Figure 4 as including Va housing | |1
to increase the flow therethrough, thus tending
attached to the pipe ||5 and provided withl a
to lower the interface 13 until the float returns ’
with apvalve 15.4 Extending upward from the pipe
14, and thuscommunicating with the water in the
lower part of the tank 10, is a pipe 16, this pipe
cap ||8 which may be permanently or adjustably
of treated oil moving from the upper portion of 25 spaced therefrom to provide an annular passage
||9 through which the dispersion is delivered to
` the tank 10 through a pipe 85 maylsi'milarly be
the lower treating space 98. A spring-loaded dis
varied by adjustment of a valve 86 therein'. y
the valve 15 to its previousposition. The amount
tributor can be used in this connection (of the
This lpurified oil maybe moved to'subsequent
typé shown in Figure 4) Vand can be made to
refining equipment, either with orl without addi
tional settling time, but is shown as discharging 30 exert a mixing action on the incoming constitu
ents at the point of discharge into the ñeld, this
into a tank 81 from which any water separating
being‘often desirable though not essential to the
from the oil can be withdrawnÍ through a pipe 88,
operation of the process. For example, the cap
the oil being pumped from this tank to suitable
||8 may carry a rod |20 slidable ina spider | 2|
refilling equipment for distillation, cracking, or
and carrying a passaged spacer element |122. By
other processing, if desired. The valves 15 and
disposing a compression spring |23 between the
' 86 act to maintain a; >all times sufficient super
spider |2| and the spacer element> |22, the cap
atmospheric pressure in the tank v'|0'to prevent
||8,'will be moved?resiliently downward and will
such vaporization of the lighter fractions of the
be displaced upward a distance determined by
oil as might interfere with satisfactory separa
the rate of input of the dispersion.
Various means may be utilized for energizing
The electrode system of this treater is disposed
the electrodes to establish suitable electric ñelds
in an oil environment of sufficient resistivity as
in the treating spaces 91 and 98. In the construc
to permit maintenance of the electric ñeld under
given operating conditions. In this connection,
_tion shown, all of the electrodes 90, 9|, 94, and
95 are maintained above ground potential, the
I prefer to use a live electrode structure suspended
only grounded portions adjacent the electrodes
Y from insulators 89, and shown as including' an
being the distributor HB, Ythe tank 10, and the
upper live electrode 90 and a lower live electrode
body of water 12. By proper design of the elec
9| suspended therefrom and electrically con
trical system, the potential between the inter
nectedtheretov by rods 92. - Suspended from an
mediate electrode structure and the electrodes 90
insulator 93 and positioned between the upper
and'9l can be made much higher than the p0
and lower live electrodes 90 and»9| is an inter
tential between any of the live electrodes and
mediate live electrode structure, shown as in
the grounded portions of the system. In Figure
cluding electrodes 94 and 95 joined by a1 con
l, such a lsystem is shown as including lîWO trans
ducting rod 96. These electrodes cooperate re
spectively‘with the electrodes 9|]V and 9| in pro 55 formers |25 and |26 Yproviding secondary wind
viding upper and lower‘treating spaces 91` and Y
ings connected in additive relation. One ter
minal of each secondary winding is grounded as
918.
indicated by the numeral |21, and the remaining
Theelectrodes 90, 9|, 94, and 95 are preferably
terminals are respectively connected to the inter- ~
of interstitial character, and the constructional
details of the embodiment shown'will be clear by 60 mediate electrode structure and to the upper and
reference to Figures 1 and' 3. Referring to Figure
lower live electrodes 90 and 9|. Suitable switches
and control means for limiting the current may
beV used'in the primary circuits of these trans
3, the electrode 90 may include'a plurality of con
centric rings lllß mounted on pins |0| secured to
cross arms |02. Each ring provides ajlower‘annu
Assuming, for example, that each transformer
lar edge |04 adjacent which thel electric field is 65
'very concentrated. The ‘electrode ‘94 is similarly
develops a potential of 121,000 Volts, the potential
formers.>
formed, with a pluralityv of concentric'rings |05
terminating in upward-extending annular edges
|09. By disaligningthe rings |00 and' |05, the
K
v
'
A across the upper treating space 91 will be V24,000
volts, as will also the potential across the lower
treating space 98. However, the potential be
tween the distributor ||6 and the electrodes 9|
or 95 will be only 12,000 volts, as will be the ñeld
inducing potential between the‘lower electrode 9|
and the body of water 12, and which ñeld is often
desirable in further treating the settling water
preferably of smaller diameter than the electrodes
75 Vmassesas Well as in sludge elimination. Use of
90fand 94.
most intense portion of any electric'ñeld estab 70
lished in the treating space 91 Will-be inclined~
as indicated by the dotted lines |01. The elec
trodes 9| and 95 are similarly- formedY and are
2,404,405
>such a system tends .to »prevent short-circuiting
to tliedistributor and .also Ypermits introduction
of the dispersion directly .into afield ofhigh volt
age. It will be „apparent lthat by using different
_quence can Abe used WithoutA departing from the
.electrode` spacings and/or- different potentials,
viously described, .or these actions can be used
spirit _of .the invention. The smaller ,droplets
`can be >'formed either exclusively by the mixing
means 30 ror by the injection of steam, as pre
the voltage gradients in the. spaces 91 and 98 and
together. If steam is introduced through the
the intensities of the treatingactions therein may
pipe .59 .to supply the small droplets, the rela
tively `fresh water added through thepipe 2,1 can
be controlled as desired -to .produce the best treat
ing effects on the oil being processed.
b_e dispersed into the -oil to form droplets of an
The preferred mode of operation is one in 10 average size somewhat larger, .and ‘the relatively
which the dispersing stepsare socontrolled as to
fresh Water added through the pipe, 4'5 lcan be
produce a dispersion which .is continuously >re
dispersed in vsuchrnfianner thatzthe average size
of the resulting dropletsv is even larger, thus mak
' solvable With the aid of an `electric field into oil
and water, Without the accumulation of such
ingpossible a _Wide range-of particle size.
amount of sludge -as Would yinterfere with the 15
I usually 4.und it desirable to ,add atleast the
last portion ofthe relatively freshwater to the
maintenancefof the electric field. This resolution
can `be effected by coalescing treatment .in the
oil at a position quite close to the electric field,
electric field, aided, if desired, by .recycling
, and, in most instances, itis desirable kto add the
first portion immediately ahead of the Isecond
through the electric field Vas mentioned above,
followed by settling or other separating steps. 20 portion. However, if desired, the -ñrst portion
If the dispersing steps are properly controlled,
can be added to the oil a considerable time -prior
resolution into oil and water can be obtained,
to the addition ofthe laterjportion Without de
the Water being substantially free of oil, Within
commercial tolerances, .but now containing the
parting _from the ‘spirit of the invention.
impurities extracted from the oil, either in their 25
original or `somewhat modified state.
Such a
`
One-Verydesirable _mode of operation in purify
ing an oil containing dispersed impurities is'to
avoid predominant combination of these dispersed
impurities with ‘the relatively -fresh :Water until
mode of operation Will prevent'the accumulation
of suchamountof sludge, comprising unresolved
the dispersion enters the electric ñeld. This in
sures that droplets of the relatively fresh Wa
emulsion, as would ,interfere with the mainte
nanceof the electric field.
30 ter "will be present in the dispersion ìto be acted
If the incoming .oil contains .suspendedim
upon by the field to bring them intoassociation
or combination with the dispersed impurities.
purities, these yare Aoften yof very small size.. It
'The amount of relatively fresh Water used in
has been found desirable to have some of the
relatively fresh Water .droplets of a commen
thevprocess Willvary with different voils and With
-surate oronly slightly larger size as this appears 35 the >desired degree of purification. 'I'he Water
content of the dispersion entering the'electric
to `increase the total >percentage reduction of
impurities. If the relatively fresh water is added
field should not be so ‘high as 'to producefinvefrse
phase emulsions of the oil-in-Water-type in such
at a single point, vfollowed by -such mixing as
will `produce particles-of this small, size, itis found
amount as cannot be handled by the electric ñeld.
onmany voils that sludge ,difficulties are encoun 40 The vupper limit onmost oils appears to'be be
tered, as evidenced either by the inability to'
low 40% or 50%. Usually, the Water content
of the dispersion 'is Aconsiderably Aless `and vmay
maintain coalescing potentials across the elec
commonly >rangebetween 8% and 30%. Ifjthe
trodes .during continuous operation, _or Iby the
progressive accumulation of >alayer of vsludge in
incoming voil contains vrno Water, or contains'no
the interfacial zone which -~eventually may build 45 more than 2% or 3% vof water, the total amount
of relatively fresh water added Will usually be
up either to short-circuit the eelctrodes or to
found within the range of 5% vto >20% 4to 'bring
gradually pervade the >bodies of -oil and Water,
the total Water content of ‘the dispersion to at
thus preventing the continuous >Withdrawal from
least about 8%, and the most desirable percent
the treater of substantially oil-free Water and
50 age can be determined empirically. Likewise,-the
oil of suitably low Water content.
By the present invention, I can add a portion
relative amounts of Water »added at the different
of the yrelatively fresh Water at one stage of the
stages of the process will vary with' different »oils
process and control the dispersing action toppro
andgno fixed Avalues can begiven. In some in- ’
duce such ,small droplets of relatively ~fresh wa
stances, the proportions added through the pipes
ter, and can add another portion of the .rela 55 21 and 45 can be commensurate With each other
tively fresh Water at another stage of .the proc
but, in other instances, itwill be found desir
ess and control the dispersing action to produce
able to introduce relatively less Water through
the pipe 21 than through the pipe 45.
droplets of relatively fresh Water of an average
size larger than those produced in _theñrst stage.
If mixing valves aroused to Vdisperse the rela
In this manner, I can control very definitely the 60 tively fresh Water into the oil, thepressure drops
proportion of small droplets and the proportion
thereacross willvbe controlled to yproduce the de
of larger droplets, and, if desired, can produce a
sired type of dispersion, as outlined above.l No
dispersion containing Water droplets differing in
fixed values Vcan .be given in this -connection'fon
size very materially and of a` homogeneity range
Withsome oils, the -total drop in pressure from 4the
considerably different and larger .than is pos
p_ipe‘20 to the interior of the treater can be much
sible in other processes. This has beenfound
larger than with .other oils. It Vcan be said, vhovv
very >desirable and conducive to `ahigher per
ever, that the >particle size of the relatively fresh
centage ,removal of impurities, _as well as >mak
Water decreases as the pressure drop vacross an
emulsifying valve increases. >Correspondingly, if
ing possible the continuous treatment of .Oils kat
-high throughput .rates with substantially _com 70 the relatively fresh Water introduced through the
plete vresolution While still obtaining the desired
pipe 2.1 is to form the _desirable smalldroplets,
reduction „in impurities. ,
.
the pressure drop lacross the mixing 'valve 3|
.I prefer to `disperse „the _smaller droplets in
will usually be greater than the pressure, drop
the oil prior to the dispersion of the ,larger drop
across the subsequent valve ~5l. It will be un
lets ~.in the `system sl'iovvn,y but the 4opposite se
derstood that the. desired mixing Yaction can be
2:1104, ¿10,5
.
mentioned above so as to be effective in removing
valvef15l', orequivalent restriction, may some
timesbe eliminated .andreliance vplaced- upon
turbulence. in the >pipe H5 `or in the distributor
'.Ill-iY Lto yform the desired. dispersion. Once the
small.. droplets of relatively fresh water are dis
persed in ,thev oil, they will-not beV materially
disturbed by.a Vlater and relativelyflessV intense
-
'
-
»
impurities from the oil.
Q '
a combination of the water from the tanks25 or
48 and the eiiiuent water from the treater.y B'y
blendingthe eiiluent water with the water` nwith->
drawn from only one of these tanksyit is thus
possible to secure a multi-compositionl system,
tivelyfresh waterrat superatmospheric pressure,
and it is often desirable in this instance to have
particularlyïin the system> shown in lFigure l. The
pumps 2|', 26, and“, as wellas Ythe >valves 58er
the smallest droplets formed by the condensing
of steam, with droplets of next-larger average
k:tIL'can be yused- to proportionthe( oil andvwater
size comprising some >of the eilluent water while
the droplets of largest average size contain less
Vconstituents». ~ The pressureY »exerted by these
pumps islpreîferablyV suflicientrto force _the d_is-4 .
persion into >the' treater and maintain a super y20
atmospheric/«pressure therein. Pressures Ain the
treater tank 'HlV between Y10 and 50 lbs/sq.
orgabOVe, can be used but, in'most instances, a
or none of the ellluent water.
Y
averagesize composed in part of eñluent water
and the droplets of larger average size composed
of .the water in one of the tanks 25 or 48, usually
the latter, though the invention is not in all in
-25
stances limited to this mode .of operation. This
velectric iield is-preferably superatmospheriabut
the most desirable temperature will vary with
different» oils.A ~Ordinarily,- temperatures .from
1009-1“,V up to fthe 4boiling point of -wate'rr> at the
,
Even aside from the use of Asteam in the process,
itis often desirable to have the droplets of smaller
pressure'in'this-tank of about 25flbs./sq. in. is. y
appears to lead to improved treatability and ex
cellent operation of the process in general.
Various changes and modifications can be made
without departing from the Spirit ofY the inven
tion as defined in the appended claims.
ab
pressure existingrinthe tankV ‘l0 can be used with
»success-¿and some oils- are susceptiblerto treat-V Y
ment at atmospherictemperatures.
y ,
persed droplets, the additional and supplemen
tary relatively fresh water may often desirably be
y
,
, y
When using steam toform the smallest dis- .
Itis preferredto- mix> the oil with Vtherela
V
.
can .be determined empirically. The resulting
combined waterk should still be relatively fresh as
thegmixingor dispersing means. Likewise, >the '
Y
12Y
tivelyr fresh and eiiluent water, andthe best ratios
_stricted passages Í can be .substituted . as y forming ¿
Ydispersing >or mixing> action.
_
45a and |45 will control the proportions of rela
obtained .without _i~e.~io1d;ing_.Y to . adjustable V.Lor
.weight-loaded valves, and suitable orifices,Y orjre
I claim as my invention: ,
TheY heat
1. A process for removing water-dispersible im-„. t'
« can -befsupplied entirely by use of theheat ex-.
Y changer 53,-or'the Voil-and water constituents can 35 purities from a mineral.y oilfof low or negligible
Water content, which process includes .the steps
be preheated Vbythe use >of the heat exchangers
of: adding relatively fresh water to said oil and
mixing the added water and the oil in aiirst
4VThepreiîerredV mode of operation isV to` use Va
mixing step to form an oil-continuous dispersion
process which is continuous throughout,»for ìex
ample, one-in which Vthe portionsY of` relatively 40 containing the relatively fresh water in the form
of droplets; later adding more relatively fresh,
-fresh water are> added successively to al stream of
Water to said dispersion and mixing the later
Voil.^-- However, semi-continuous - or batch vopera
added Water and said dispersion „in a second mix
tions are within the contemplation of the pres
ing step to disperse the later-added relatively
fresh
water into the oil-continuous dispersion in
" Injsome Vinstances-it Vis desirable to the process
'the form of droplets 'in the oil, said mixing steps
- to re-use a portion of the water separating in the
22,29, or 46.-.
ent invention.
_
»-
..
^
.
.
`
»
.
.'
.
being controlled in such manner that the drop
electric‘rtreater, -re-combining this portion with
l lets of the relatively freshwater later added are Y
a more -pure'water before dispersingit into `the
of an average size diiïerent from the droplets of
oil.¿*Theîrelatively'fresh water resulting from -
the relatively fresh water ñrst added toV produce
an emulsion containing'diiîerent-sized droplets
of the water suspendedv in the oil; subjecting said
suchY a combining step gives improved results` on 7
Y many-¿oilsr as evidenced by decreased sludging
tendencies, lower cuts of the purified oil, and
emulsion to the action of an. electric lield of
higher process efficiencyV invv general including a
greater percentage removal of impurities.` While _
thereasons for these phenomena arenot com-` »
su?licientv intensity to coalesce the water to form
coalesced masses comprising impurities from the
oil; and separating the coalesced masses from
pletely understood,Y it has been discovered thatV
the oil.
the eiiluent watercontains, asa result of the proc- s
assisting inthe resolution ofV water-in-oil emul
.
`
v
.
Í
2. A process for removing saline material from
e'ss, desirable counter-emulsifying agents` extract
>ed >from the-oil, Ythese agents being of the type
a mineral oil of low or negligible water content,
said saline material being dispersed in the oil
in the form of small saline particles, which proc
ess includes theV steps of : ñrst emulsifying into
said Voil small droplets of relativelyfresh water
of a size commensurate with the dispersed ‘saline
particles; then emulsifying into the oil larger
60
If/such a mode of operation is desired, a portion
Vof the'elliuent water can be moved through pipe
|40. as *,controlled by valve vHH and delivered
through-another valve I 42 to the pipe-2l. The
M0 4canÃcommunica-te with the intake ofÍth'e . _ dropletsv of relatively fresh water to produce
_an oil-continuous emulsion containing `dispersed
, pump„.26 .orrmayïbe equipped’with a separate
saline particles along with said small and said
.-.pumptfor delivery of the effluent water» tothe '
larger» droplets; subjecting the oil-continuous
i, discharge side of thepump 26.
Y
. „
emulsion to the action of .an electric ñeld to
îj’_L«Similarly}if}it-is-desired to'blend a lportion of
coalesce thewater andbring the saline material
Y »theefIiuent-waterlwith the water drawn >from‘the
into assoôiation therewith; and separating the
,.tankßß, YAalvalve |45. in a pipe |46Ícan »be opened
_ `to deliverall- or aportionof the stream v'fromthe
.pipellllûlt'othepipe 45.
y coalesced 4Water and its' associated saline mate
.
The relative settings of valves YZ'Ida'ndp l|42 or
`rial fromtheoil.
75
._
l
,_
»
~
3, A Continuous process for'removing water
2,404,405
13
14
dispersible impurities from a mineral oil of low
or negligible water content, which process in
cludes the steps of : continuously mixing with
water content, which process includes the steps
of: first adding to the oil and mixing therewith
in a first mixing step a -iirst portion of relatively
fresh water to disperse the relatively fresh water
into the oil as droplets of heterogeneous particle
a stream of said oil a proportioned amount of
relatively fresh water to disperse same through
out the oil stream in the form of small droplets
size with an intermediate particle size predom
to form a stream of oil-continuous dispersion;
inating in number; then adding to this disper
later continuously adding to the stream of oil~
larger than said small droplets iirst dispersed in
sion and mixing therewith in a second mixing
step a second portion of relatively fresh Water to
disperse the water' thus added into the oil as
droplets of heterogeneous particle size with an
intermediate particle size predominating in num
ber, the intermediate particle size produced by
said ñrst mixing step being smaller than the in
to the oil to form a stream of a resulting electri
15 termediate particle size produced by said second
continuous
dispersion- another
proportioned
amount of relatively fresh water and mixing this
water with the oil-continuous dispersion to dis
perse this water into the oil of the dispersion in
the form of droplets having an average size
cally-treatable oil-continuous dispersion capable
mixing step and the range of particle size be
of being continuously resolved with the aid of a
coalescing electric field into oil and water with
out the accumulation of such amount of sludge
tween the smallest droplets produced by the ñrst
mixing step and the largest droplets produced by
the second mixing step being greater than the
range of particle size produced by either of said
mixing steps individually; subjecting the result
as would interfere with the maintenance of said
electric field; and continuously subjecting said
stream of said resulting dispersion to the action
of such a coalescing electric ñeld to coalesce the
water into masses of sufiicient size to settle from
the oil and collect as a body of water below said
electric field.
4. A process for removing water-dispersible
impurities from a mineral oil of low or negligible
ing oil-continuous' dispersion to the action of a
coalescing electric field to coalesce the dispersed
droplets thereof into masses comprising said im
purities and of a size to settle from the oil; and
gravitationally separating said masses from the
oil.
'
CLAUDIUS H. M. ROBERTS.
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