Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01B—BOILING; BOILING APPARATUS ; EVAPORATION; EVAPORATION APPARATUS
  • B01B1/00—Boiling; Boiling apparatus for physical or chemical purposes ; Evaporation in general
  • B01B1/02—Preventing foaming
  • B01B1/04—Preventing foaming by chemical means

Definitions

• the present invention relates to improved antifoaming compositions which are added to water that is subjected to boiling, as in the boilers of locomotives, stationary steam generators, evaporators, and in other instances where the boiling of water occurs, especially under superatmospheric temperature and pressure conditions, whereby the tendency of the water therein to foam is prevented or reduced and the boiling characteristics of the water so improved that priming of the steam generator and carryover of boiler water with the steam therefrom is prevented.
• these fatty materials or glycerides are very unstable under severe hydrolytic conditions encountered in steam generation, particularly under the conditions of superatmospheric pressure, the corresponding high temperatures and the alkalinity of the boiler water.
• the resultant decomposition products which remain in the boiler tend to increase the foaming tendencies of the boiler water and to accumulate in such a way as to give a compound dirty boiler, necessitating frequent washing.
• cerice tain of the decomposition products thus produced, or sometimes even the materials themselves have a definite volatility with steam and will, therefore, steam-distil out of the steam generators, thus appearing in the steam and in the eventual condensate. This, of course, is also undesirable.
• antifoaming agents usually are of such a low order of efficiency that they have to be employed in relatively large quantities, adding not only to the expense but also to the inconvenience of operating the steam generators; and since they are so unstable their eifectiveness is of short duration, necessitating the continual charging into the boilers or other steam generators of relatively large amounts of these older antifoaming agents.
• One of the objects of this invention is to provide a new and improved process for preventing the foaming and priming of steam generators, thus improving the quality of the steam produced thereby.
• Another object is to provide new and improved compositions for adding to the water in a steam generator to prevent or reduce its tendency to foam.
• Another object is to provide antifoaming compositions which are effective to prevent foaming when used in very low dosages.
• a further object is to provide highly effective antifoam compositions which are readily and easily dispersible when added to the feed water entering a steam generator.
• Another object of this invention is to provide antifoam compositions in which the active efi'ective ingredients are readily soluble in water at relatively low temperatures, (e. g., 75 F.) but decrease in solubility when the water is heated to relatively high temperatures such as are employed in the generation of steam under superatmospheric pressures and the corresponding temperatures.
• Still another object of the invention is to provide a process of generating steam and new and improved antifoam cmopositions therefor wherein the period of effectiveness of the antifoam composition is greatly prolonged as compared to the period of effectiveness of other antifoam compositions presently known in the art.
• Still another object of the invention is to provide a new and improved process of inhibiting foaming during steam generation which permits operations at higher dissolved sogids contents than has heretofore been considered possi e.
• An additional object is to provide new and useful antifoaming compositions of an extremely high order of resistance to decomposition under the conditions prevailing in steam generation. Other objects will appear hereinafter.
• the antifoam agents employed in accordance with this invention can be described as addition products of a primary and/or secondary amine and an alkylene oxide which is either ethylene oxide, 1,2-propylene oxide, or a mixture of ethylene oxide and 1,2-propylene oxide, the resultant addition product being substantially insoluble under steam generating conditions.
• the products employed for the purpose of the invention can also be described as amino ether alcohols characterized by a polyoxyalkylene group having different terminal groups connected to different carbon atoms, the oxyalklene groups being either all oxyethylene, mixed oxyethylene and oxy- 1,2-propylene groups, or all oxy-1,2-propylene groups.
• the preferred products have oxyalkylene groups derived from at least 6 part of 1,2-propylene oxide for each part of ethylene oxide by weight.
• the resultant amino ether alcohols have different terminal groups connected to different carbon atoms, one of said terminal groups being a hydroxy group and the other being a substituted amino group. If the amine initially employed contains a terminal primary amino group the terminal amino groups of the final product will be a secondary amino group. If the amine initially employed contains a terminal secondary amino group the terminal amino group of the final product will be a tertiary amino group.
• the resultant compound contains amino groups linearly connected to polyoxyalkylene groups and the terminal groups are hydroxy groups.
• the amino groups are interiorly positioned in the structure of the compound and are not terminal groups.
• the compounds which have proven to be satisfactory for the purpose of the invention have all been relatively high molecular wei ht compounds having a molecular Weight of at least 1200.
• the amine employed as an initial reactant is water insoluble and the reaction product of the alkylene oxide and the amine are water soluble at ordinary temperatures and water insoluble under steam generating conditions.
• the initial reactant can be water soluble and the resultant end product can be Water insoluble under ordinary and elevated temperature conditions.
• aliphatic amino ether alcohols characterized by a structure containing oxyethylene and oxy1,2-propylene groups in the same molecule, having dilferent terminal groups connected to different carbon atoms, one of said terminal groups being a hydroxy group and the other a substituted amino group, and having a molecular weight of at least 1200, the oxyethylene and the oxypropylene groups being derived from a weight ratio of 1,2-propylene oxide to ethylene oxide within the range of 1:3 to 9:1, preferably about 1:1.
• EXAMPLE I A mixture of equal parts of ethylene oxide and 1,2 propylene oxide was supplied to a reactor charged with 20 parts of n-butylamine and 0.8 part of dry powdered sodium hydroxide.
• the ethylene oxide had a water content of about 0.09% and an acetaldehyde content of about 0.06% and the 1,2-propylene oxide had a water content of about 0.05% and a propionaldehyde content of about 0.15%.
• the n-butylamine was substantially anhydrous.
• the pressure maintained during the introduction of the oxide mixture was about to 22 p. s. i. (pounds per square inch gauge) over a period of about 2 hours and, thereafter, the mixture was cycled for a period of an additional hour. During the reaction the temperature was held at 90 to 100 C.
• EXAMPLE II A mixture containing equal parts of ethylene oxide and l, 2-propylene ox1de was supplied to a reactor charged with 20 parts of di-n-butylamme and 0.8 part of dry powdered sodium hydroxide. The pressure maintained during the introduction of the oxide mixture was about 10 to 30 p. s. 1. over a per1od of about 2 hours and, thereafter, the mixture was cycled for a per1od of about 1 hour. Durmg the reaction the temperature was held at 90 to 115 C.
• the products employed as herein described may be liquids or low-melting wax-like solids, and may be entirely soluble in cold water or only partially soluble. In the latter case, they are relatively easily dispersed in the feedwater by means of additional dispersing agents, as described below. All of the products exhibit substantial insolubility in hot water, the phenomenon of decreasing solubility in water with increasing temperature being characteristic of compounds of this class which contain multiple ether linkages and in which the ratio of ether linkages to carbon is sufficiently great to permit the weak hydrogen bonding effect of the ether oxygen to confer water solubility.
• an antifoam agent employed in inhibiting the foaming of water in a steam generator will depend upon several factors, among them the per cent of solids in the foaming liquid, the nature of the solids, the alkalinity, temperature, and pressure, the type and degree or circulation in the steam generator, the rate of steam production, and the amount of foam suppression desired. It is, therefore, impossible to state any rigid rules for estimating the amount of an antifoam which needs to be used.
• the amounts of the amino ether alcohols of this invention which are required are, however, extremely small. For many purposes, amounts of the order of 0.01 grain per gallon to 0.02 grain per gallon in the feedwater are sufficient, and under certain conditions quantities as low as 0.001 grain per gallon in the feedwater have proved effective. In general, it can be said that quantities greater than 0.1 grain per gallon in the feedwater would seldom be required.
• the previously described proportions can be converted from grains per gallon to parts per million by multiplying the grains per gallon by the factor 17.1.
• the experimental boiler used was of the type described in the publication Solid Matter in Boiler Water Foaming, by Foulk and Brill, which ap peared in the periodical Industrial and Engineering Chemistry, volume 27, pages 143035.
• This boiler was fitted with sight glasses on each side of the steam release space so that conditions in the boiler in a Zone several inches above and below the normal water level were observed while the boiler was operating under pressure. It was also equipped with an automatic water level control which held the water level within a range of 10.25 inch.
• a feedwater (herein referred to as a 210 grain water) was used having the following composition, expressed in parts per million, by weight, with an M alkalinity of 30% of the dissolved solids.
• compositions described as Ucon materials were made by Carbide and Carbon Chemicals Corporation.
• the letter H signifies that the compositions are heteric in that they are made from both ethylene oxide and 1,2-propylene oxide.
• the letters BA indicate that the amine employed as an initial reactant is butyl amine.
• the letters DBA indicate that the amine employed as an initial reactant is dibutylamine.
• EXAMPLE III The material tested as an antifoam in this test was UCON 50 HBA 607 which is the monobutyl amine derivative of a polyoxyalkylene glycol containing a weight ratio of ethylene oxide to propylene oxide of 1:1, and possessing an average total molecular weight of approximately 1269 as determined by calculation from data obtained by the Menzies-Wright method and a viscosity at 100 F. of 607 S. U. S. This material was completely soluble in the feedwater at room temperature, and was dissolved in the feedwater at a dosage of 0.005 grain per gallon. Carryover did not occur until the total dissolved solids in the boiler water had reached 596 grains per gallon.
• compositions derived from monobutylamine and dibutylamine cover the employment of compositions derived from monobutylamine and dibutylamine.
• any other primary or secondary amine can be used as one of the initial reactants to yield products having valuable antifoam characteristics. This'reaction is only limited to those amine compositions having 1 or 2 replaceable hydrogen atoms attached directly'to the nitrogen atom.
• primary and secondary amines of the alkyl series, the cycloalkyl series, aryl series and aralkyl series are suitable.
• Suitable monoamines are amylamine and diamylamine, cyclohexylamine and dicyclohexylamine, aniline and diphenyl amine, benzyl amine and dibenzyl amine, methyl amine and dimethyl amine, ethyl amine and diethyl amine, isopropyl amine and diisopropyl amine, butyl amine and dibutyl amine, decylamine and didecylamine, dodecylamine and didodecylamine, octadecylamine and dioctadecylamine, alpha-naphthylamine and beta-naphthylamine.
• Suitable polyamines are ethylene diamine, propylene diamine, butylene diamine, decamethylene diamine, diethylene triamine, triethylenetetramlne, tetraethylenepentamine, diisopropylenetriamine, trusopropylenetetramine, o-, mand reactant is initially water insoluble.
• the preferred compositions also are those in which the composition as a whole is aliphatic rather than aromatic.
• the amino ether alcohols employed in the practice of this invention can all be incorporated into dry powdered p phenylene diamine, benzidine and naphthylenediamines.
• the preferred compositions are those in which the amine materials such as powdered tannin, sodium lignin sulfonate, desulfonated lignin, soda ash, various orthophosphates and polyphosphates.
• amounts of the amino ether alcohols of the order of to 10% of the total composition may be readily incorporated to give a dry-appearing pulverized product.
• suitable binders and other well known techniques such compositions may also be briquetted.
• a small amount of soap such as the alkali metal soaps of oleic acid or tall oil, or a sulfonated oil, may be employed with good results, and the amount of soap or sulfonate thus required is insufiicient to interfere with the powerful antifoam effect of the ether alcohols or to render the boiler compound dirty.
• the amino ether alcohols of this invention may be prepared in the form of dry-appearing pulversized or briquetted compositions which are readily and completely dispersible in water with a minimum of agitation by incorporating them, with or without a dispersant such as soap or sulfonated oil, with various tannins. lignins. or other pulverized chemicals, either alone or in combination.
• EXAMPLE B Per cent Amino ether alcohols described in Examples I to IX 8 Soda ash 72 Sodium septaphosphate The mixing was done as described in Example A by addin: the liquid to the mixed dry solids. The resultant pulverized product was readily and completely soluble in cold water.
• EXAMPLE C Per cent Amino ether alcohols of Examples I to IX 3 Desulfonated lignin 97 This composition was mixed as in Example A and the dry compostion obtained was readily and completely dis persible in water in a concentration of 3 to 5%.
• EXAMPLE D Per cent Amino ether alcohols of Examples I to IX Refined tall oil 2 Desulfonated lignin derivative 95 This composition was readily and completely dispersible in water, the residual alkalinity of the lignin derivative serving to convert the refined tall oil to soap when the composition was added to water.
• the lignin derivative used herein was that obtained directly from the sulfite pulp manufacturing process after removal of the bulk of the wood sugars, converting the calcium sulfonate to the corresponding sodium salts, and drying.
• composition described was readily dispersible in water.
• the quantity of the amino ether alcohol is within the range of 0.5% to 12% by weight of the total composition and the total quantity of tannins, sodium lignin sulfonate and/or desulfonated lignins is within the range of about 50% to about 88% by weight of the composition.
• the practice of the invention is applicable to the inhibition of foaming in steam generation over a relatively wide pressure and temperature range.
• steam is generally generated at pressures around 250 pounds per square inch and the corresponding temperatures. Excellent results have been obtained with the practice of the invention at pressures within the range of to 300 pounds per square inch and the corresponding temperatures.
• the invention can also be used, however, in connection with the generation of steam at much higher pressures and the corresponding temperatures, as, for example, in stationary boilers operating at pressures as high as 1000 to 1500 pounds per square inch.
• the compositions employed in accordance with the invention are effective not only in inhibiting foaming but also in conditioning and improving the quality of the steam. For this purpose, they may be used in even smaller amounts than the amounts required for the complete inhibition of foaming and priming.
• the amino ether alcohols employed in the practice of this invention are desirably used in conjunction with other organic Water treating chemicals of the tannin and lignin types in treating many water supplies as will be seen from the following.
• suflicient of hydroxylated organic material such as tannins, tannic acid, gallic acid, pyrogallol, catechol, phloroglucinol, etc., be added along with the amino ether alcohols.
• These hydroxylated organic compounds have the ability of nullifying the bad effects of the magnesium hydroxide.
• Magnesium hydroxide appears to partially selectively adsorb the antifoam material and so take it out of the boiler water so that the full antifoam action cannot be exerted by the antifoam compositions when in this adsorbed state.
• magnesium hydroxide appears to lose its ability to interfere with the antifoam action.
• tannins, sodium lignin sufonate and/or desulfonated lignins are not necessarily incorporated with the antifoam composition prior to the addition of the latter to the feedwater. Where it is desirable to use tannins, sodium lignin sulfonate and/or desulfonated lignins, these substances may also be added directly to the boiler Water.
• the following table illustrates the quantity of the tannins, sodium lignin sulfonate and/or desulfonated lignins which can be employed satisfactorily to nullify the action of the magnesium salts on the amino ether alcohol antifoam ingredients.
• a method of generating steam from'a boiler water having 'a tendency to foam on boiling which comprises dispersing in said water a quantity of an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylene oxide, the average molecular weight of said addition product being at least 1200 and said addition product being substantially insoluble in said boiler water at the temperature of steam generation, the quantity of said addition product being effective to inhibit the tendency of said water to foam on boiling, and heating the resultant aqueous dispersion to the boiling point.
• a method of generating steam from a boiler water having a tendency to foam on boiling and which contains magnesium compounds which comprises dispersing in said water a quantity of an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylene oxide, the average molecular weight of said addition product being at least 1200 and said addition product being substantially insoluble in said boiler Water at the temperature of steam generation, and a quantity of a hydroxylated organic compound from the group consisting of tannins, sodium lignin sulfonate and desulfonated lignins effective to nullify the action of said magnesium compounds on said addition product, the quantity of said addition product being effective to inhibit the tendency of said water to foam on boiling, and heating the resultant aqueous dispersion to the boiling point.
• a method of generating steam from a boiler water having a tendency to foam on boiling which comprises dispersing in said water a quantity of an amino ether alcohol characterized by a polyoxyalkylene chain having different terminal groups connected to different carbon atoms, one of said terminal groups being a hydroxy group and the other being an amino group, said amino ether alcohol having a molecular weight of at least 1200, the oxyalkylene groups in said amino ether alcohol being from the group consisting of oxyethylene and oxy-l,2- propylene groups and being derived from at least /3 part of 1,2-propylene oxide for each part of ethylene oxide by weight, said amino ether alcohol being substantially insoluble in said boiler water at the temperature of steam generation and the quantity of said amino ether alcohol being effective to inhibit the tendency of said water to foam on boiling, and heating the resultant aqueous dispersion to the boiling point.
• an amino ether alcohol characterized by a polyoxyalkylene chain having different terminal groups connected to different carbon atoms, one of said terminal groups being a
• a method of generating steam from a boiler water having a tendency to foam on boiling and which contains magnesium compounds which comprises dispersing in said water a quantity of an amino ether alcohol characterized by a polyoxyalkylene chain having different terminal groups connected to different carbon atoms, one of said terminal groups being a hydroxy group and the other being an amino group, said amino ether alcohol having a molecular weight of at least 1200, the oxyalkylene groups in said amino ether alcohol being from the group consisting of oxyethylene and oxy-l,2-propylene groups and being derived from at least /3 part of 1,2-propylene oxide for each part of ethylene oxide by weight, said amino ether alcohol being substantially insoluble in said boiler water at the temperature of steam generation, and a quantity of a hydroxylated organic compound from the group consisting of tannins, sodium lignin sulfonate and desulfonated lignins effective to nullify the action of said magnesium compounds on said addition product, the quantity of said amino ether alcohol addition product being effective
• a method of generating steam from a boiler water having a tendency to foam on boiling which comprises dispersing in said water a quantity of an addition product of an aliphatic monoamine from the group consisting of primary and secondary aliphatic monoamines and an alkylene oxide from the group consisting of 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylon boiling, and heating the resultant aqueous "dispersion to the boiling point.
• a method of generating steam from a boiler water having a tendency to foam on boiling and which contains magnesium compounds which comprises dispersing in said water a quantity of an addition product of an aliphatic monoamine from the group consisting of primary and secondary aliphatic monoamines and an alkylene oxide from the group consisting of 1,2-propylene oxide and mixtures of both ethylene oxide and1,2'-propylene oxide containing at least /3 part by weight of 1,2-propylene oxide per part of ethylene oxide, the average molecular weight of said addition product beingat least 1200 and said addition product being substantially insoluble in said boiler water at the temperature of steam generation, and a quantity of a hydroxylated organic compound from the group consisting of tannins, sodium lignin sulfonate and desulfonated lignins effective to nullify the action of said magnesium compounds on said addition product, the quantity of said addition product being effective to inhibit the tendency of said water to. foam on boiling, and heating the resultant aqueous dispersion to the boiling point
• a process of minimizing the production of foam in and the priming of steam generators operating under superatmospheric pressure conditions which comprises incorporating with a Water therein containing an amount of total dissolved solids tending to produce foaming and priming a quantity of a foam inhibiting composition within the range of 0.001 grain to 0.1 grain of said compound per gallon of said water, said composition being an addition product of an amine from the group consisting of primary and secondary amines and a mixture of both ethylene oxide and 1,2-propylene oxide containing at least /3 part by weight of 1,2-propylene oxide per part of ethylene oxide, the addition product being water insoluble under steam generating conditions and the molecular Weight of the addition product averaging at least 1200.
• the process of minimizing the production of foam in steam boilers during steam generation which comprises incorporating in a water therein containing an amount of total solids tending to produce foaming an addition product of dibutylamine and a mixture of both ethylene oxide and 1,2-propylene oxide containing at least /3 part of 1,2-propylene oxide per part of ethylene oxide, the average molecular weight of said addition product being at least 1200 and said quantity being sufficient to substantially inhibit said foaming.
• the process of minimizing the production of foam in steam boilers during steam generation which comprises incorporating in a water therein containing an amount of total solids tending to produce foaming an addition product of dibutylamine and a mixture of both ethylene oxide and 1,2-propylene oxide in approximate weight ratio of 1:1, the average molecular weight of said addition product being at least 1200 and said quantity being sufficient to substantially inhibit said foaming.
• a liquid for the generation of steam comprising 11 a Water containing an amount of total dissolved solids tending to produce foaming and priming when heated to the boiling point and 0.001 grain to 0.1 grain per gallon of said water of an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylene oxide, the aver age molecular weight of said addition product being at least 1200 and said addition product being substantially insoluble in said boiler water at the temperature of steam generation.
• a liquid for the generation of steam comprising a water containing magnesium compounds and an amount of total dissolved solids tending to produce foaming and priming when heated to the boiling point and 0.001 grain to 0.1 grain per gallon of said water of an amino ether alcohol which is an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylene oxide, the average molecular weight of said addition product being at least 1200 and said addition product being substantially insoluble in said boiler water at the temperature of steam generation, and a quantity of a hydroxylated organic compound dispersed in said water from the group consisting of tannins, sodium lignin sulfonate and desulfonated lignins, said quantity being efiective to nullify the action of the magnesium compounds on said addi- 30 tion product.
• An antifoam composition for minimizing the production of foam in the generation of steam from water which comprises essentially 0.5 to 12% by weight of an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2- propylene oxide, the average molecular weight of said addition product being at least 1200 and said addition product being substantially insoluble in boiler water at steam generating temperatures, and 50% to 88% by weight of a substance from the group consisting of tannins, sodium lignin sulfonate and desulfonated lignins.
• a method of generating steam from a boiler water having a tendency to foam on boiling which comprises dispersing in said water a quantity of an addition product of an amine from the group consisting of primary and secondary amines and an alkylene oxide from the group consisting of ethylene oxide, 1,2-propylene oxide and mixtures of both ethylene oxide and 1,2-propylene oxide, the average molecular weight of said addition product being within the range from 1200 to 3000 and said addition product being substantially insoluble in said boiler water at the temperature of steam generation, the quantity of said addition product being effective to inhibit the tendency of said water to foam on boiling, and heating the resultant aqueous dispersion to the boiling point.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

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Cited By (18)

Citations (2)

• 0
  • IT IT500132D patent/IT500132A/it unknown
• 1952
  • 1952-01-16 US US266777A patent/US2701239A/en not_active Expired - Lifetime

Patent Citations (2)

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