US2203778A - Method for producing steel - Google Patents

Description

June 11, 1940. M. w Dn-TQ METHOD FOR PRODUCING STEEL Filed July ll, 1959 3 Sheets-Sheet 1 June 11, 1940. M. w. DIT'ro 2,203,778

METHOD FOR PRODUCING STEEL Filed July ll, 1939.

3 Shaets-Sheet 2,

June ll, 1940. M grr-ro METHOD FOR PRODUCING STEEL NIN www Z,

Patented June 11, 1940 METHOD Fon PRODUCING STEEL Marvin W. Ditto, New York, N. Y., assignor to Emulsions Process Corporation,` N. Y., a corporation of Delaware New York,

Application July'll, 1939, Serial No. 283,902

16 claims.

This invention relates to an improved method for producing steel in metallurgical furnaces, and

more par Bessemer ticularly to the production of steel in a converter or furnace.

In using a Bessemer converter, it is well known that molten pig iron or cast iron is poured into the furnace and a blast of air is turned onand introduced into the molten metal.

Each ton of pig iron contains about 75 .pounds of carbon, 25

pounds of silicon, 1 pound of sulphur, and 15 pounds of manganese, most of which will be burned o fuel.

ut. These elements are ordinarily the The molten iron is at a temperature of about 2200 F. when poured into the converter.

In a few minutes after the blast of air is turned on, the burning of these elements in the iron raises the temperature of the charge to about 3500 F. and man rect amo added to Most of the carbon, silicon, sulphur ganese4 are burned out, and ordinarily,

no external fuel is necessary. When the impurities are burned out, the corunt of carbon and manganese, may be give the steel the nal composition desired. I The steel is then poured from the converter into ingots ready to be made intg shapes 30 burning of a water-in-fuel oil emulsion or its equivalent during the blast period.

Due to my improvements, the total air introduced into the furnace is preheatedu and the water inthe emulsion is raised to the llame tem- 35 perature of the burning fuel. Consequently, the

Water vapor entering imo reaction -with the carbon of the fuel oil is dissociated into carbon monoxide and hydrogen.

As a result of introducing ,a gas rich in oxygen, (resulting from the further the molt dissociation of the water vapor by contact with en iron in the furnace), the FeO rate' of formation is increased. The water `being a relatively rich bearer of oxygen, lreduces the'I amount of atmospheric oxygen required, theretroduced fore, by my process, the amount of nitrogen ininto the furnace is reduced. By regulatingy the amount of fuel introduced into the blast air,

`it is possible to increase and maintain` the temperature of the metal after normal reso. actiQnS 1i ave taken place. As a result of a larger amountfof oxygen available andthe large amount of hydrogen present, thev rate of sulphur reduction is in phur iS g u" metal.`

creased, and ai larger percentage of sulasied and eliminated from the molten By introducing hydrated lime into the emulsion, alarger percentage of phosphorus can be eliminated by the reaction with the calcium.` Irons running higher in phosphorus than are normally used in Bessemer practice are made available by my procedure. A,

Furthermore, in accordance with my invention, I can govern themoisture content of the blast air used in the` furnace, and this can be accomplished by increasing or decreasing the amount of Water in the emulsion in accordance with the moisture content of the blast air.l For example, in Winter time, the relative humidity of the blast air may be as low as and at such times I will increase the amount of Water forming part of the emulsion. On the other hand, in the summertime, the humidity may be as high as 95%, and atsuch times, I will decrease the amount of water incorporated n the emulsion.

lI-Iaving now indicated in a general Way the nature and purpose of my invention, I will' proceed to a detail description thereof, with reference to the accompanying drawings, in Which I have illustrated a preferred embodiment, and in which:

Fig. 1 is a vertical sectional View of a portion of a Bessemer converter modified to accord with my invention.

Fig. 2 is a View similar to Fig. 1, but taken on the line 2--2 of that figure.

Fig. 3 is a horizontal sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a oW diagram 'showing the converter hooked up with the means for supplying a Waterin-fuel oil emulsion to the converter.

Referring to the drawings, 6 .designates a Bessemer converter having a shell a base ring 8, hanger bolts- 9, bottom shell Ill, refractory lining I I, tuyre blocks I2, tuyres I3, tuyre block supporting ring I4, combustion arch I5, refractoryI bottom shell lining I6, wind duct I1, burner opening I8, atomizing nozzle I9, fixed emulsion conveyin'g header 20, flexible emulsion conveying tube 2I,'trunnions 22, air supply conduit 23, main air supply pipe 24, trunnion supports 25, Worm tilting gear 26, Vreduction gear 21, motor 28, and

ltangential air portsl^29.

So far as the converter is concerned,`all of the parts, with. the exception of I8, I9, and 2|, are of more or Yless conventional construction, 50 and the motor 428 is employed in theusual way to operate `the gearing to cause the converter to move' from a vertical position 7to a horizontal one, and vice versa.

I Referring 'now to.

the flow sheet in Fig. 4, 1t lili` pipe 32 and be discharged through a pipe 33. The

. preheated oil is passed through a pipe 34 into one end of a proportioning pump 35, preferably of a type to permit variation of the proportions pf liquids pumped while the pump is in operation. A good example of such a pump is disclosed in my application Serial No. 230,480, led September-` 17, 1938, although I can accomplish the same purpose by employing a pairof pumps of the type illustrated in the U. S. patent to Fenchelle, No. 1,289,716. l

The hot oil is forced by such a pump structure at high superatmospheric pressure through a pipe 36 into a manifold 31 that leads to a motor driven emulsifying mill 38 which may be of the kind disclosed in the Russell U. S. Patent No. 2,059,535, but is preferably of the type disclosed in my application Serial No. 218,883, filed June 12, 1938.

Water which may be preheated, is fed to the opposite end of the proportioning'pump through a conduit 39 having a control valve 40, and the water is forced under high superatmospheric pressure from the pump through a pipe 4I into Ithe manifold 31 where it may be mixed with the hot oil before the mixture is introduced into the inlet of the emulsifying mill. In the latter, the

water and oil are incorporated into a relatively stable water-in-fuel oil emulsion, and the hot emulsion, due to the pressure imparted to the liquids by the pump 35,is forced through a pipe 4Ia into an emulsion heater 42 where the temperature of the emulsion may be raised to any desired degree by` superheated steam or the like. The steam is introduced at 43 and discharged at 44. 'I'he highly heated emulsion is passed from the heater 42 through a pipe 45 into the header 20, from which it may be passed through the flexible tube 2| to the nozzle I9 of the converter.

In practicing the process, the emulsifyirig mixer or dispersion mill 35 converts the oil and `water into an oil phase emulsion, and this emulsion, in

heated condition, is fed to the nozzle I9.

In practice, the blast air for the converter is passed through pipe 24, conduit 23, wind duct I1, and tangential ports 29, into the combustion chamber 46 of the converter, and due to the tangential ports, it is given a whirling motion. This air being under a pressure of approximately 25 to 40 pounds per square inch, is lturned into the furnace when the latter is in a horizontal position for reception of the molten pig iron charge. As the furnace is tilted back into vertical tion, the pressure of the tuyres ing through the tuyres, and the air passes upwardly into intimate contact with the metal during the blow period. Simultaneously, when the air blast is turned on, the valve (not shown) controlling the supply of hot emulsion, is opened, and' the emulsion is introduced into the combustionv chamber 46 and ignited, and combustion takes place under the pressure conditions existing in this chamber. This results in an intense rate of combustion, due to the fact that the burner I9 is at the center of the vortex of the whirling currents of air.

I have found that the` ignitibility and combustibility of the emulsion can be maintained with as much as 50% of water being incorporated into the fuel oil, and that upon combustion, the water impounded in the emulsion is immediately drated lime to the water.

posiraised to the temperature of the flame. At these temperatures, part of the water reacts Withl the carbon to form carbonmonoxide and hydrogen gas; these products, including the water vapor resulting from excess water not entering into the reaction, are forced by the air stream through the tuyre blocks and into the metal at the base of the furnace. The highly heated water vapor when brought in contact with the hot metal, reacts with iron to form FeO and hydrogen. Also, it will enter into reaction with the manganese of the molten pool to form MnO and hydrogen, and also will enter into reaction with the sulphur to. form SO2 and hydrogen. (Some of the sulphur 'will enter into reaction withhydrogen to form carbon monoxide and carbon dioxide. It is assumed that the larger part of the carbon content of the iron is oxidized as a result of reaction between the carbon and IieOI resulting in the following reaction: FeO plus carbon equals Fe and CO.

As water contains a larger percentage of oxygen than atmospheric air per pound by weight, by this means of introducing water into the converter, a gas rich in oxygen is introduced, and it eliminates the necessity of supplying all the oxygen from the atmosphere.

One objection toBessemer steel hasv been the large amount of iron nitride formed as a result of high temperature, and the combination of iron "with nitrogen in the atmosphere. By enriching therefore there is less tendency to combine with n nitrogen to form the objectionable nitrides.

Pig iron running high in phosphorus can be reduced to the minimum by the addition of hy- Such hydrated calcium may be introduced into the pipe 39 through a valved pipe 50. l By my apparatus, it is possible to introduce this lime in a finely divided state4 into the metal bath, and intimately disperse the same :throughout the molten metal. Therefore, the slag resulting from oxidation of silicon segregates the impurities and will contain the lime and phosphorus in the form of calcium phosphate.

'I'he phosphorus will then be carried out of the converter with the slag.

By the means disclosed herein, a better quality of Bessemer steel can be obtained, and by the control o f the percentage of water introduced into the converter, better control of operating conditions is made available.

Reverting to the control of the percentage of water, it will be noted that this can be accomplished by means of the valve 40, and I prefer to control such valve by any suitable means responsive to movements of any preferred type of hygrometer 40a, as this will enable me to control the moisture content of the air 'in the combustion chamber 46. A suitable hygrostatic controller is shown in the patent to Grisby, No. 1,219,390, March 13, 1917. By such apparatus, as the relative humidity of the blast air increases, the hygrometer will cause partial closing of the valve 40 so as to reduce the volume of water incorporated intothe emulsion. If, for vbest operating conditions it was found that-the relative humidity the necessary heat to the water so that there will be no heat demandupon the furnace conditions to take care of the water passing through the furnace, as the temperature of the products of combustion ofthe emulsion can be raised to approximately the temperature of the name at or adjacent to the tuyres, so that they can immediately enter into reaction with the other 4products-of the furnace.

Also by my improved procedure, I can not only condition the air employed in a Bessemer furnace, but can control the moisture content of the air introduced into any type of metallurgical furnace which would be benefited by maintaining a uniform atmospheric condition within the furnace at all times. In other words, I believe, operating under such conditions, that practically all types of furnaces, Where control of water vapor is beneficial/such as open hearth, blast, cement kilns, lime kilns, enameling and japanning furnaces will Vbe benefited by my method of operation.

While I have disclosed what I now consider to be preferred modes of procedure, it will be understood that changes I nay be made in the details disclosed, without departing from the spirit of the invention, as expressed in the claims.

What I claim and desire to secure by Letters Patent is:

11 In the production of steel in a Bessemer converter, introducing blast air into A the lower portion of a pool of molten pig iron, simultaneouslyj introducing into said air an intimate mixture of water and fueloil 'in atomized condition, and burning such mixture in intimate contact with the air as the latter enters the molten pig iron.

2. In the conversion of ferrie metal high in carbon into steel in the presence of atmospheric air, introducing into the bottom of a `pool of such molten metal an intimate lmixture of water and fuel oil in atomized condition, and burning such mixture in intimate contactw'ith the air as `the latter contacts with the molten mtal, and

thereby forming ferric oxides. I

3. In the production of steel in a Bessemer converter, introducing blast air into the lower portion of a pool of molten pig iron, simultaneously introducing into said air an emulsifled fuel having water as a component thereof, and burning such fuel in intimate contact with the air as the latter enters the molten pig iron.

4. In the conversion of ferric metal high in carbon 'into steel in the presence of atmospheric t air, preheating an intimate mixture of water and fuel oil, and then introducing such mixture in atomized condition into said air, and burning such mixture in intimate contact-with the air as thelatter enters the bottom of a pool of the metal while the metal is in molten condition.

5. In` the production of steel in a Bessemer converter, introducing blast air into the lower portion of a pool of moltenipig iron, simultaneously introducing in said air a highly heated intimate mixtureof water and fuel oil in atomized condition, and burning such mixturev in intimate contact `with the air as the latter enters the molten pig iron.

6. In the production of steel in a Bessemer converter, organizing blast air into a whirling current and passing such current into the lower portion `of a pool of molten pig iron, simultaneously introducing into said current of air an intimate mixture of water and' fuel oil in atomized condition, and burning such mixture in intimate contact with the air as the latter enters the molten pig iron.

7. In the conversion of ferric metal Vhigh in -carbon into steel, forming a pool of such metalin molten condition, organizing a stream of blast air into a whirling current and introducing such air into vthe bottom of the pool, simultaneously introducing into the vortex of the air'current an intimate mixture of water and fuel oil in atomized condition, and burning such mixture in intimate Contact with the air as the latter enters the bottom of the molten pool.

8. In the production of steel in a Bessemer converter, introducing blast air into the lower portion of a pool of molten pig iron, simultaneously introducing into said air an intimate mixture of water, fuel oil and lime, and burning such fuel oil in contact with the air as the latter enters the molten pig iron.

9. In the conversion of ferric metal high in carbon into steelin the presence of blast air, introducing an emulsied fuel having water as a component thereof into said air as the latter enters the bottom of a molten pool of such metal, and burning said fuel in intimate Contact with the air .as the latter enters the molten pool.

10. In the oderation of a furnace utilizing atmospheric air, maintaining the moisture content water and fuel oil'in atomized. condition, and f maintaining the moisture content of the air within predetermined limits by increasing the water content of the mixture as the moisture content of-the air decreases, and decreasing vthe water content of the mixture as the moisture content of the air increases. N

` 12. In the conversion of ferrie metal high in carbon into steel in the presence of blast air, introducing into saidI air an intimate mixture of water and fuel oil in atomized condition and maintaining the "moisture content of the air within predetermined limits by increasing the water content of the mixture as the moisture content of the air decreases, and decreasing thewater content of the mixture as the moisture content of the air increases, and burning said mixture in intimate contact with the air as the latter contacts such metal While the latter is in molten condition.-

13.I In the production of steel in a Bessemer converter, introducing blast air into the lower portion of a pool of molten pig iron, simultaneously introducing into said air an intimate mixture of Water and fuel oil in atomized condition, maintaining the moisture content of said air Within predetermined limits by varying the Water content of the mixture, and burning such mixture in intimate content with the air as the latter enters the molten pig iron.

' ously introducing into said air an emulsified fuel having water as a component thereof, maintaining the moisture content of the air within predetermjned limits by varying the water content of the emulsied fuel, and burning such emulsified fuel in intimate contact with the air as the latter enters the molten pig iron.

15. In the conversion of ferrie metal high in carbon into steel in the presence of blast air,

introducing into said air an intimate mixture of water and fuel oil in atomized condition, maintaining the'water content of the mixture at a predetermined degree to accord with thefmoisture content of the air, and burning such mixture in intimate contact with the air as the latter is contacted with the metal while the mealis in molten condition.'

16. In the production of steel in a Bessemer converter, introducing blast air into the lower portion of a pool of molten pig iron, simultaneously introducing into said air an intimate mixy ture of water and fuel oil in atomized condition,

maintaining the Water content of the mixture at a predetermined degree to accord with the moisture y-content of the blast air, and burning such 'mixture in intimate contact with the air as the latter enters the molten pig iron. y v MARVIN W. DI'ITO.

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