US2481899A - Prevention of foaming in steam generation - Google Patents

Description

Mos EOAMING INt TEQM 7 Dela-ware.

Y Homema- A mi m SEWILNO. 1.15 13 hefpresent invention relates-tqantifoaming com-positions 'which-areused in-steamboilers anjd similar steam generators, evaporatoz a; .etcu to overcome the tendency of; the water thereinfto foam "and "hence i150 bring about, *Zhfi priming of the steam generator or theilike One of the objects of the present invention e e l Q i ni a le"fiqr h i s 20 steam'in steam generators angl coznprising water containing very small quantitiesoi parjticular kinds o b t ut ram t g-N-slibsfiitmsd"a a amides, fib whenfsu hbwai r E 13; 9 h i n mi mais samih il c Q w b in hemes aso at d h equestit t n sfth reiiliwill 'n tbr s b u excessive foaming and the resulting ginning, these o xb n sub nt ally .1 1 1e i e amr edi iabl hfitihQ-Y'WW s retained by the; water ar d 4 eltherythev rioi their decomposition products wil-l -anpear inft and the resulting condensationftherep his well knolin'in theqpetation Psteam boilers, suchas in electric p 'plaiit locomotives and :thelike, "QIE *eyapoigators that the water therein,- even thoughifiitial'lrit shgws very little tendency to foam, will, when-the amount of total solids 'thereii -approacl es a relatively high concentration; *develoir a=-veryfde cided tendency to foam. Whenfthis occursfqonsiderable quantities of water-are phgsicaliy'qarried out-of the boilers or evaporators with fthe steam, thus app aring in the s team-f:lines "and in the eventual condensate, sflh'-piifnjimgljias many clisadvantages'because ittendsto qontaminate the steam"l ines, to player vcorrode the 4 valves, and under -'serious;-'condi tions*niay-even impair the cylinders=anlipistonrodsfoT the engines, or the impeller blades of tpi-binesin which the steam i is usedj for the generation-of power. Attemptshave been made in thepast 40 to control thisfo am'ingby excessi'vefi blowdown of the boilers or by"the hijection tl ereiiito of such materials as castoroil=,--tallow;-ai;1;dtlie like. While these fatty materials have somesmalltlegree of efiiciency ;they-are;*onftheptlreflhatml, quite. deficient in'that -they =-introduce- 'new {dim-- culties which, in some instaneesya reworse thaii the conditions they are *iritemiedtocure. the first place, these-fatty acids or-fgiycerities are unstable under the -conditions yex'is'tingj in the boilers, particularly as the pressure and temperatures increase, the high -"temperatures leading to rapid decompositiorrd'f the g l'yceif-ides,

which, if "anything, will tendfltofi ncreasvtho foaming and priming difliciilties. "Furthermore,

et Gla-ims.-= (outta-1532i in many instances certain;ofuthertlecomposltion products rthusxproclucedp orrscmetimesr evenethe materials themselves; havema definitewvolatility with =steam and will; therefore, :steamedistil =out ofi h t husaapp arin in c theas eamzangi in :the 1 condensate. undesirable. frEurthe more -ssuch ttyi es :of' a foaming aeentsznsuall :telativelypllargeeguant the XQ8I1SB bHE fl1SQ=IO zthe inconvenience; of; op: a in ztlaee e m ene to a sl-th e i h have afiendency-tode ompo o-so qzui .,rapidly, anat ma-the r fiectiv e s -rls:Qt hqrt r iion. which therefore. necessitatesthecontinual chargias ntothe-b lst wrl her steamese rai s.oi relatively large amounts of these colder ,antipfl mineaas nt t -M0reorer, such :antifoamin :agents eare diificult ;-to .use .:because the amounts in whichthemare. lefiicaciousare veryrcriticalhand .any-nove gdosage,usuallyhagg aavatesthe difiiculty instead ,Qf curing it.

; applioantslhave nowldiscoweredfhowever, that these iswa series sof compounds, which may be .clesi a a ub titute rami N- s tiited alkaflamid-es, whi a qnf ih h rde 0i effictency'w'hen used as an antifoaming and antiprimhis a ent, steami gene tqzs.

I 1 116 m itfi t lszw 12 'rem ssniedjb i e s'sn ial tmlilw 5H- 1,23 '1 *Y --l J-'-i( C ,.H:'-)+ C. whsn ioethe ahsti ucnt il s'a r ica d nied from: rni mt m lthesmq c nsis in /oi .1101 9.- ae lm' s zines -mmi acylalkylened amines, meseac l pet zis s and iia liaci ateo polylkscl e t nines. a mal -whole um- H V ,n ee ie fb he in .r stlez s ha t ne n? i ha osen ciq, o the rar esmndin ati ib ads w th. a t 2W ql ii-a meii b ithegr un onsis in ilin a rerme ti d.aqy a e' "PQly mQes-V By "thi FXQILQQ, s s efieqtes fiii i st et t e tw 1 20 .qtaqy ate s mmin ihi swe r .idu qtt ssf sl seii-ac d bs weeef lnhe com unds Qfi hisiinve im! hav fbssn sm ared: 9' be .1. 95 ifi i it a a it i amiagems it' l ,a y ce vqan q ql he a i aisli; qlmmins ar iatt .1. athr andconta t eastabou 1 99:; aims and. h l eetirenpsa s h '1 tr ated w thliinqr ah inb ecu a s ze :c the in e'd "d r v ti e. i 'iSZ'i be und r tomltha the ioxmnlas wa ted n he s c f sei pnfi arid "c ams refn cqb b e" pit at hei z s lasi iven arehelieved to'*be "possessed by the compounds disclosed, or whose method of preparation is disclosed, in the specification.

The examples given below are intended to illustrate satisfactory procedures for the preparation of some of-the materials of, this invention, but are not intended to limit the invention in any way.

Example 1.-Five-hundredths mol (15.7 g.) of monostearylhydrazine was condensed with 2.825 grams (0.025 mol) of chloroacetyl chloride at 150-160 C. by adding the acid chloride to the stirred hydroziole over a minute period and, continuing to stir for 1.5 hours.

Example 2.-Monostearylethylenediamine was prepared by mixing 13.4 grams of commercial stearic acid (having a mean molecular weight of 269) and 4.4 grams of a 68.3% aqueous solution of ethylenediamine and stirring 2.5 hours at .4 The process is particularly effective at pressures of about 250 pounds per square inch.

The introduction of the antifoaming compounds of the present invention into the boiler maybe accomplished in a number of ways. Thus, thej'antifoaming compositions may be dispersed or physically mixed with, say, sodium -.!carbonate or some other material used for treating the boiler water and pumped with the feed water into the boiler by means of either an injector or a feed water pump. The compounds may also be dissolved in suitable organic watermiscible solvents such as alcohols, ethers, ke-

tones, etc., and introduced in small measured amounts into the feed water entering the boiler.

Suitable mechanical measuring devices which will periodically or continuously inject the required dosage of the antifoaming compounds 150-160 C. Then 1.9 cc. of chloroacetyl chloride was added dropwise and-the stirring and heating continued Zhours longer. 7

Example 3. Monolauryltriethylenetetramine was prepared by stirring at 150-160 C. a mixture of 10 grams of lauric acid and 7.3 grams of triethylenetetramine for 2.5 hours. Then 1.9 cc. of chloroacetyl chloride was added dropwise and the stirring and'heating continued 2 hours longer. Example 4.Monopalmitylpiperazine was pre' pared by mixing 12.8 grams of palmitic acid and 9.7 grams of piperazine hexahydrate. The mixture was then carefully heated with stirring to expel water without excessive frothing, and stirred at 150-160 C'. for 2.5 hours. Then .9 cc. of chloroacetyl chloridewas addeddropwise and stirring and heating continuedtwo hours longer. 7 Example 5. Monopalmityl p phenylenediamine was prepared by melting 5.4 grams of the diamine at about 60 C. and adding 13.7 grams of palmityl chloride, dropwise with stirring, while gradually increasing the temperature to 225 C. Stirring was continued about 30 minutes while the temperature was allowed to drop to 175 G. Then 1.9 cc. of chloroacetyl chloridewas' added dropwise and the mixture stirred at ZOO-220 C. for 2 hours.

Example 6,--.Monopalmitylhydrazine (0.048 mol) was stirred at 150-160 C. ,while,2.5 grams of beta-chlorobutyric acid was added. Stirring and heating was then continued 3 hours longer.

These compounds, while not ordinarily considered as soluble in water to any great extent, maybe suitably dispersed in water or emulsified therewith, so that effective amounts thereof may finally be'introduced and be present in the water within the steam generator under operating conditions. The emulsifying or-dispersing agent used must, however, be of a kind that, does not cause foaming, either by itself or by its decomposition prodfucts." The compounds may be used'conjointly with each other as well as with other known antifoaming agents, such as, for example, ca'stor oil.

The amounts of the above described materials which are required are extremely smalL'and in general one grain per gallon is ample. For

many purposes, however, amounts of as little as grain per gallon in'the feed water will still give valuable results, and the amounts may be even further reduced. Depending of courseupon the degree of concentration of solids, the dosage may be varied, but one grain per gallon is about as muchjas would ever have. to beused even underserious conditions, and for many purposes ou grain per gallon and even less can be used.

into the feed water may be used, so that the introduction will be more or less in proportion to the steam consumption to which the steam generator is subjected. Another manner of introducing the antifoaming compounds is to form an emulsion thereof in water and then feed said emulsion either directly into the boiler or the feed water lines leading to it. The invention therefore is not to be limited by the manner of introduction of the antifoaming composition but rather is to beconstrued in the terms of the hereunto appended claims.

We claim: i

1. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming, and a quantity of the condensation product of two mols of an acylated polyamine from the group consisting of monoacylhydrazines and monoacylated monoethylene and polyethylene polyamines, the acyl groups of said acylated polyamines containing at least about 12 carbon atoms, andone mol of a member from the group consisting of chloro lower fatty acids and the corresponding acid chlorides, said quantity being suflicient to substantially inhibit foaming and priming. 1

2. Aliquid for. the generation of steam, substantiallydevoid of foaming and priming tendencies when heated to the boiling point, comprising water containing an amount of total dissolved solids tending to produce foaming and priming and having dispersed therein a quantity of a condensation product of two mols of an acylated polyamine from the group consisting of monoacylhydrazines and monoacylated monoethylene and polyethylene polyamines, the acyl group of said acylated polyamines containing at least about 12 carbon atoms, and one mol of a member from the group consisting of chloro lower fatty acids and the corresponding acid chlorides, said quantity being sufficient to substantially inhibit foaming and priming.

3. A methodof generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved-solids. tending to'produce foaming and priming and a quantity of the condensation productof 2 mols of monostearyl hydrazine and 1 mol of vchloracetyl chloride, said quantity being sufficient to substantially inhibit said foaming and priming.

. 4. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the condensation product of 2 mols of monopalmityl piperazine and 1 mol of chloracetyl chloride, said quantity being sufficient to substantially inhibit said foaming and priming. V

6. A liquid for the generation of steam, substantially devoid of foaming and priming tendencies when heated to the boiling point, comprising water containing an amount of total dissolved solids tending to produce foaming and priming and having dispersed therein a quantity of the condensation product of 2 mols of monostearyl hydrazine and 1 mol of chloracetyl chloride, said quantity being sufiicient to substantially inhibit foaming and priming.

PAUL G. BIRD.

ARTHUR L. JACOBY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 15 Number Name Date 1,892,857 Spellmeyer Jan. 3, 1933 2,304,805 Denman Dec. 15, 1942 2,328,551 Gunderson Sept. '7, 1943