US2349517A - Calorimetry of low quality combustible gases - Google Patents

Description

May 23, 1944.

c. s. PINKERTON 2,349,517

CALORIMETRY OF LOW QUALITY COMBUS'IIBLE GAS Filed April 10, 194].

2 Sheets-Sheet 1 sample flow of the blast furnace gas.

Patented May 23, 1944 CALORIIHETRY OF LOW QUALITY COMBUSTIBLE GASES Clarence S. Pinkerton, Wauwatosa, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application April 10, 1941, Serial No. 387,876

Claims.

This invention relates to improvements in the calorimetry of low quality combustible gases. The invention relates more particularly to methods of and apparatus for enabling ignition and insuring complete combustion of a continuous sample of blast funace gas, or a low quality mixture of the latter gas with another gas or gases.

Heretofore, in respect of blast furnace gas calorimetry, great difficulty has been encountered in igniting, burning to complete combustion, and maintaining the flame of a continuous In this art special calorimeter burners-considerably more expensive than the standard burners-have been designed in an attempt to preheat such low quality gases to improve the burning conditions. However, in such prior devices it was found that the relatively large quantities of. inert gases (such as nitrogen) which are carried along with (or as a part of) the air used for combustion of the test gas have a smothering effect upon the combustion, whereby the flame may be extinguished or whereby incomplete combustion of the test gas may result.

It has also heretofore been proposed to add to the sample flow of low quality gas, such as blast furnace gas, a volumetrically proportional flow of hydrogen prior to combustion to improve combustion conditions, and then to automatically subtract the hydrogen heating value from the indication on the calorimeter to provide for ascertainment of the total heating value per unit volume of the low-grade blast furnace gas. Such use of hydrogen, however, has many obvious disadvantages and has not proved satisfactory from a commercial viewpoint.

An object of my invention is to improve the art of calorimetry of gases of low heating value per unit volume.

A more specific object is to provide methods and apparatus for continuously and accurately determining the total heating value per unit volume of a low quality gas, such as blast furnace gas, under conditions insuring complete combustion of the test gas and maintenance of the burner flame.

Another object is to provide for attainment of the aforementioned desirable results by substituting, in whole or in part, for the usual supply of combustion air in a calorimetric system or device a predetermined volumetrically constant flow of substantially pure oxygen.

Another object is to provide for use of calorimetric devices of known or standard form,

wherein only slight changes in certain structural details thereof are required to provide for attainment of the novel results contemplated by me.

Another object is to provide novel means to enable reduction or complete elimination of the supply of primary combustion air, depending upon the quality or character of the particular gas being tested.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of modification within the scope of the invention as defined by the claims.

In the drawings, Figure 1 is a schematic anddiagrammatic illustration of a calorimeter for blast furnace gas, as constructed in accordance with the present invention, the flow of oxygen for supporting combustion being supplied from a storage tank or container.

Fig. 2 illustrates diagrammatically the electrical control cricuits which are preferably employed in each form of calorimeter herein disclosed.

Fig. 3 is a sechematic and diagrammatic illustration of a blast furnace gas calorimeter wherein oxygen only is supplied as the primary combustion supporting medium for the test gas, and wherein the oxygen is supplied at a predetermined constant rate by an oxygen generator of suitable form;

In accordance with my invention substantially pure oxygen is supplied from a tank (as in Fig.

1) or another suitable source of supply (as in Fig. 3) for mixture thereof with the volumetrically constant flow of test gas of low quality (such as blast furnace gas). By this means I am enabled to eliminate entirely the undesirable and useless nitrogen, or to reduce the quantity of nitrogen to a degree which provides for obtaining the desired beneficial eifect of the oxygen in combustion of the low quality gas, due to the fact that the use of air to support combustion is avoided, or the quantity of combustion air is substantially reduced.

Referring first to Figs. 1 and 2, the same jointly illustrate a calorimetric device which is, in respect of most of the structural features thereof, like that of Patent No. 2,238,606, granted April 15, 1941, to Edwin X. Schmidt, for calorimetric apparatus, and assigned to the assignee of the present application. Here, however, as distinguished from the disclosure of said patent No.

2,238,606, the calorimetric device consists essentially of three parts, a tank unit or calorimeter proper, designated in general by the numeral 24 (Fig. 1), where the heating eifect of the test gas is measured; a recording instrument, designated in general by the numeral (Fig. 2), for translating the heat measurement into total B. t. u. per standard cubic foot of test gas, independent of variations in temperature, pressure and satura tion (humidity); and a source of supply of sub-' stantially pure oxygen (tank I66) which supplies at least a portion of the oxygen used in the combustion of the sample of gas.

The heating value of the test gas is ascertained by imparting the heat of combustion obtained from the combustion of the test gas to a mixture consisting of excess oxygen and excess air and products of combustion, and measuring the temperature rise of the mixture. The streams of test gas and air are supplied to the burner in fixed volumetric proportions by measuring devices, such as pumps 28 and 2?, respectively, which are connected to each other by gearing 28, 29 and-driven by a motor 33. Not only are the volumetric rates of delivery of the test gas and air maintained in fixed proportionality to each other, but this proportionality is effected while maintaining like conditions of temperature, pressure and saturation of the test gas and air by means of a common water seal 3! for the motor driven pumps 26 and 21.

The quantity of air supplied by pump 21 is divided by means of suitable piping as illustrated to provide a stream of primary combustion air through conduit Illil, a stream of secondary combustion air through conduit NH, and an additional stream of air through conduit Hi2. The flow of air from pump 2'! through piping I63 to conduit IE2 is substantially free and unrestricted; Whereas the flow of air from said pump to conduits Idil and I6! is restricted, as by means of a suitable orifice shown diagrammatically at I64. The flow of air to conduit IIlEI is further restricted, as by means of the orifice I05.

In accordance with my invention a continuous and volumetrically constant flow of substantially pure oxygen is supplied from the tank or container W6, through conduit I67, restriction or fixed orifice Itil and conduit I89, for mixture within conduit iIil (extending upwardly through the tank liquid) with the supply of primary combustion air from conduit IIIU. The flow of oxygen thus, attains substantially the same temperature as the news of gas and air. The means for maintaining a substantially constant volumetric rate of flow of oxygen through conduit I09 preferably comprises a pressure regulator IIII, including a valve III located Within conduit Illl, a pressure-operated diaphragm III for controlling the degree of opening of valve I I i said diaphragm being subjected, through pipe M2 to pressure of the fluid on the upstream side of restriction I08. The volumetric rate of flow of oxygen through conduit I09 is subject to manual control, as by means of a nut III which adjusts the degree. of compression of a spring i to thereby vary the degree of loading of the pressure regulator III.

Conduit I ill is-provided at its upper end with a restriction or orifice I I3, the outlet end of which communicates with a chamber H4, wherein said oxygen and primary combustion air are thoroughly mixed with the stream of test gas, said chamber being preferably provided with a baflle,

shown in dotted lines at IM to facilitate such mixture of the fluids.

The test gas, such as blast furnace gas, is piped to the tank unit 23 where it passes through a restriction 33 into the inlet pipe 34 of the gas pump 23. The upper portion of pipe 36. designated by numeral 3d is open to atmosphere at a suitable point of disposal. The lower portion of pipe 34 connects directly with the inlet end of gas pump 25. The orifice 33 is adapted to limit the rate of flow of test gas, and inasmuch as the comparatively large opening through the pipe 35 to atmosphere prevents any pressure from building up in the inlet pipe 34, the gas is metered by pump 26 at substantially atmospheric pressure, and the level of the water seal 3| on the inlet sideof pump 26 is at the same level as the main body thereof in tank 2 3.

The connection between the aforementioned driving motor 3!] and gas pump 25 includes builtin speed reducing gearing 36 upon said motor, and change speed gearing, designated by the numeral 3?, which includes the gear 39 attached to pump 26. The aforementioned gearing 29 includes the gear 42 which is fastened upon the shaft of air pump 2?. The character of the pumps 26 and 2'! and the driving and supporting means therefor are described in detail in the aforementioned Schmidt Patent No. 2,238,- 606.

The outlet of gas pump 26 has a conduit connection 48 with the aforementioned mixing chamber H4. The various connectors interposed between pumps 26, 21, conduit I If] and the other elements of the piping are shown as rising above the level 3! of the water, thus providing simple leak-proof water-sealed connections which can be conveniently opened for inspection; the removable connectors providing for substitution of other elements to function in the manner and for the purposes hereinafter described. Most of the air from pump 2! passes through connector piping I03 into pipe I02, thence upwardly inside of burner IE5 between combustion tube H6 and the tube II'I surrounding the latter, such air mixing with the products of combustion prior to passage of the latter through the portion N8 of the burner H5 in which the hot junction HJ (Fig. 2) of the thermocouple is to be located, as illustrated in the aforementioned Patent No. 2,238,606.

A smaller proportion of the air from pump 21, after passing through restriction I04, connector IZ Il and conduit IBI, passes upwardly inside of the combustion tube I I6 where it meets the burner flame I 2I and furnishes secondary air of combustion. A still smaller proportion of the air from pump 2? passes through a further restriction I 05 and conduit I00 to the point of conjunction of the latter with conduit I09 through which oxygen is supplied; the primary air and oxygen being thoroughly mixed within and jointly flowing through conduit I18 and restriction H3 to the aforementioned chamber "I I4 Where they are mixed with the continuously flowing sample of the test gas supplied by pump 26. The combustible mixture flows from chamber H4 through a restriction I22 and conduit I 23 and through the central tube I24 of. the burner. Combustion takes place at the top of said tube I24, certain elements carried bythe burner cap I25 being removable to permit initial ignition of the combustible mixture to provide flame I2I.

The products of combustion mix with the excess'air to form the heat absorbing medium;

' HJ of the thermocouple.

, in the thermocouple.

The heat absorbing medium passes into intimate contact with the aforementioned hot junction Some of the heatabsorbing medium passes through openings I26 in the burner cap and the remainder passes down the annular passage I21 formed by the return flow bafile I28 and then upwardly through the burner cap openings I29 to atmosphere. The cold junction CJ (Fig. 2) of the thermocouple is positioned within a cup or cylinder (not.

shown) which is partly submerged in the tank water 3|, as disclosed in said Patent No. 2,238,- 606, said cup also containing the thermometer resistance RT, whose function is fully disclosed in said Patent No. 2,238,606.

The electromotive force generated by the difference in temperature between hot junction HJ and cold junction CJ is a measure of the heating effect of the test gas. It is this electromotive force which is translated into heating value in the recording instrument (Fig. 2). The water level in the main portion 2% of tank 24 is maintained by an oscillatory pump comprising a cup 62, said cup being carried by and communicating with a pipe 64 bent to substantially L-shape. The shorter arm of said pipe 64 overhangs the main portion 24 of the tank, for discharging into the latter, as shown in Fig. 1. The details of construction and the operation of said oscillatory pump are disclosed in the aforementioned Patent No. 2,238,606, to which reference may be had. The recorder herein employed (Fig. 2) is preferably of the self-balancing potentiometer type, and is substantially identical in construction and mode' of operation with that disclosed in Fig. 1 of said Patent No. 2,238,606, the same reference characters being employed for the parts of Fig. 2 hereof as in Fig. 1 of said patent.

Here, as in said Patent No. 2,238,606, the battery I3 (Fig. 2) supplies a very small continuously flowing current to the potentiometer circuit, the current being maintained substantially constant by hand adjustment of rheostat M.

The electromotive force generated by the thermocouple (CJ and HJ) in the tank unit is applied across the battery terminals, through galvanometer G and switch H3 in the upper or run position thereof, wherein contacts l9 are bridged. Contact H is moved along resistor S until galvanometer G returns to its balanced position, indicating that the potential drop through part of S is equal to the electromotive force generated Deflections' of galvanometer G are amplified mechanically and the arrangement is such that slider H (and indicator and recorder 12) is automatically moved to the balancing position.

The portion of the battery voltage used in checking the potentiometer current is the voltage drop across S and the compensation thermom-,

eter RT in series, paralleled by resistance R the whole parallel circuit being in series with resistance II and a portion of rheostat VR. The portion of VR included for checking of the potentiometer current is determined immediately following standardization of the calorimetric device on hydrogen, and the position of contactor 15 of rheostat VR. remains fixed until a subsequent hydrogen test indicates the need for a change in this setting.

The resistance of compensation thermometer RT changes with variations in temperature of the tank liquid, and changes the value of current flowing through slide wire resistance S but does not appreciably affect the flow of current from battery l3. The change in current flow through S corresponds substantially with the variation (due to tank temperature change) in the electromotive force generated in the thermocouple, so that the position of the indicator and recorder 12; that is, the instrument reading, is unaffected by changes in tank temperature. Since the current flow from battery 13 is substantially unaffected by changes in value of the compensation thermometer resistance RT, and since the change in resistance across which the potential drop is measured when standardizing is very small, standardization may be effected independently of tank temperature over the entire operating range of the instrument; namely, from 60 degrees F. to degrees F. tank temperature.

The calorimetric device is standardized by burning a sample of pure hydrogen, whose total heating value per unit volume and combustion characteristics are well known; a special set of hydrogen test gears (not shown) being substituted for certain of the gears in gearing 31 (Fig. 1) to thereby provide a reading at a point on the scale I0 (Fig. 2) where the accuracy of the reading is best. The recorder circuit is then adjusted so that a reading is obtained which will insure a correct reading on the particular gasfor which the instrument is being standardized. With a fair knowledge of the approximate composition of the particular gas, standardization on hydrogen insures accuracy of the calorimetric device throughout its total range of operation.

As will be apparent from the foregoing, descrip tion; because of the slow burning propertiesof blast furnace gas with air, a portion of thextheoretical amount of oxygen, required for the combustion of the testgas, is supplied as pure oxygen and is mixed with the test gasafter metering of the latter. With blast furnace gas having a total heating value of 75 B. t. u. per cubic foot, this flow of pure oxygen should be approximately fifty per cent. of the theoretically required amount of oxygen to provide maximum stability of the burner flame. Where the total heating value per unit volume of the test gas is higher, the desired percentage of the theoretically required amount of oxygen supplied as pure oxygen may be made correspondingly lower.

Quantitatively the volumetric rate of oxygen flow is very small in comparison With the volumetric rates of flow of test gas and air, and has no measurable effect upon the heating value measurement, other than that the oxygen without nitrogen has a very beneficial effect upon the burning properties of the blast furnace gas, giving a steady flame, without any likelihood of incomplete combustion of the test gas, and without possibility of accidental extinguishment of the combustion flame.

The calorimetric device for blast furnace gas illustrated in Fig. 3 is generally quite similar to that illustrated in Fig. 1, identical parts in the two figures being designated by like characters of reference. As aforestated, the indicating and recording device and the control circuits thereof illustrated in Fig. 2 may be and preferably are employed with each of the devices of Figs. 1 and 3. The device of Fig. 3 is distinguished from that of Fig. l primarily in respect of eliminating any flow of primary combustion air for mixture with the combined flow of pure oxygen and test gas prior to combustion of the latter; and in respect of the source of supply of pure oxygen.

Referring more specifically to Fig. 3: The test gas of low quality (such as blast furnace gas) is supplied to the tank unit 24 as by means of a 'suitable pump P, from theoutlet -end of which it "passes through a small orifice nipple 33, and thence through piping I and I3I-into the inlet head of gas pump 25. Theupper end portion of pipe I3I connects the inlet head of pump 26 with an open burner I32 of sufl'icient size or areato prevent any pressure building up in said inlet head at the rate of testgas flow fixed by the orifice 33 in said nipple.

Inasmuch as the orifice nipple 33 is in practice adapted to limit the flow of the gas sample to about three cubic feet per hour, and since the comparatively large opening through the bleeder burner I32 to atmosphere prevents any pressurefrom building up in the inlet head of pump 2B,the sample of test gas is metered by pump 26 at atmospheric pressure and the water level at the inlet head of pump 26 is at the same level as the main body of the water 3| in tank 24. I

Gas pump 26 is driven by motor 30, with 'built in gear reduction 36, through change gearing designated by the numerals 28, 31 and 39. The air pump 21 is also driven by motor 3%, through gear reduction 36 and the gears 4V and 42, the latter being attached to the shaft of pump 21. Both the gas pump26 and the air pump 21 are of the multiple compartment meter type, so constructed that when they rotate they take in, seal off, and discharge fixed volumes of gas and air, respectively, into their respective discharge chambers. These pumps are 50 constructed, in a Well known manner, that the gas and air are respectively pumped at approximate ly uniform rates.

Both pumps 26, 21, the complete motor drive therefor, and the burner structure are preferably mounted upon the same base casting (not shown). In operation this unit is mounted upon the tank 24 which is partially filled with "water, the body of water providing a common seal (level 3|) for both pumps and also having a temperature equalizing effect, as is well understood by those skilled in this art. I

The outlet end of gas pump 26 communicates, through piping I33 and connector I34 with the pipe I23 leading to the bottom of the base of burner IIE and to the inner tube I24 .of the humor. The flow of pure oxygen passes from the generator I35 through a pipe or riser I36 .from the bottom of tank 24, thereby attaining substantially the same temperature as. the aforementioned fiows of gas and .air. The top of riser I36 opens into a bell I31 mounted upon a knife edge pivot I38 permitting .a rise or fall of the bell. The oxygen connection I32 with the outlet end of gas pump 26 alsoterminates inside of hell I3! and has a water sealed orifice .cap I over its open end inside of said bell. Oxygen from generator I 35 thus flows into bell I31, out through the orifice cap I42 and connection I39 into the stream of gas from pump 26. The orifice cap I46 offers a restriction to the flow of oxygen, tending to lift the oxygen bell I ,31.

Said bell I3? is balanced, by a manually ad- 7 justable weight MI, in such a manner that the pressure inside the bell must rise to effect arise of the bell. Therefore, in the event of any possible slight fluctuations in the rate of delivery of the oxygen from the generator I35, the prover bell I31 will rise or fall, thus tending to reduce the range of fluctuation in. the rate of flow of oxygen to the burner, while avoiding building up of any objectionably high pres-sures in the oxygen generator system. 3

The lcalorimetric .device of Fig, 3 is (like the device of Fig. '1) preferably standardized by burning a continuously flowing sample of pure oxygen, whose total heating value :per unit vol- -,I0 (Fig. 2) Where the accuracy of the reading is good. During standardization, no oxygen should be used as explosions might occur. For this purpose a blank cap is preferably substituted for the orifice cap I40 within bell I31.

Tests of the purity of oxygen generated in a generator such as .that illustrated at I35 show that the oxygen contains no impurities which might produce heat in combustion. The change in heat capacity of the products of combustion due to addition of oxygen or any possible change in the rate of flow of oxygen is not sumcient to measurably change the reading, so that use of or omission of oxygen has no effect upon. the reading, except that it eliminates any possibility of incomplete combustion of the test gas, and insures against accidental extinction of the burner flame, as aforementioned. Upon proper ad Justment of the indicating and recording circult (Fig. 2) to provide the correct reading in respect of the standarizing gas (hydrogen) such adjustment will likewise insure correct readings in respect of the gas or gases for which the instrument is being standardized. With a fair knowledge of the approximate composition of the low quality. gas (such as blast furnace gas) to be'tested, such standardization of the instrument insures over-all accuracy of the lat- Although any suitable form of oxygen generator may be employed, the preferred form thereof shown diagrammatically at I35 in Fig. 3 comprises a tank I42 and a cover or closure I43 therefor, both of which parts are formed of any suitable electrically non-conducting material. Cover I43 has depending therefrom an insulating separator I44 which entirely surrounds a tantalum electrode I45 which penetrates cover I43 and extends downwardly a substantial distance into tank I42. The lower end of separator I44 is open to provide for access thereinto of the body of electrolytic fluid I46, preferably sulphuric acid, contained within but not completely filling the tank I42. A lead electrode I41 penetrates cover I43 and extends into tank I42, preferably to the same depth as electrode I45, said electrode I47 being located exteriorly of separator I44.

Electrodes I45 and I4! are electrically connected with the respective terminals of the secondary winding I48 of a transformer I48, whose vprimary winding I48 has its terminals connected with a suitable source of alternating current supply represented by lines L and'L the arrangement being such that the choice of electrolyte and electrodes produces a rectifying efiect whereby an adjustable value of direct current is supplied to said electrodes. The rate at which oxygen is generated is, of course, dependent upon the value of current supplied to the electrodes; an ammeter A being provided to indicate the current value and to facilitate adjustment thereof to the desired value or amperage.

As is well understood, the arrangement illustrated is such that substantially pure oxygen is generated at the lead electrode Id-lqand bubbles upwardly through the electrolyte into the space above the latter exteriorly of separator I44. Seated upon and sealed to the upper surface of cover I43 is a member I49 formed of a suitable insulating material, such as glass, to provide two superimposed chambers I 49, I49. A weir pipe I50 extends upwardly through cover I43 to a predetermined height within chamber I49 to control the level II of a body of water therewithin (which may contain a small quantity of sulphuric acid, as an incident to its washing action upon the oxygen which bubbles upwardly therethrough). Pipe I50 extends downwardly into tank I42 below the level I46 of electrolyte within the latter. In like manner a weir pipe I52 extends upwardly into chamber I49 to control the level I53 of a body of water therewithin, and downwardly into chamber I49 belowthe level I5I of water within the latter. A pipe I54 extends downwardly through the upper end wall of chamber I43 to a point below the water level I53 to seal off the lower end of said pipe, and to provide a passage whereby the volume of water in each of the chambers I49 and I49 may be replenished, the excess volume of water finally passing to tank I42 to replenish the water dissociated in the latter as an incident to the generation of hydrogen and oxygen.

The generated oxygen passes upwardly from tank I42 through a goose-neck I55 whose upper end opening is positioned below the level I5I' of water within chamber l49 such oxygen bubbling up through said liquid I5I, and passing thence to a second goose-neck pipe I56 whose upper end opening is positioned below. the level I53 of water within chamber I49, and after bubbling upwardly through said water I 53 the oxygen passes into conduit I36, as aforedescribed.

In view of the fact that hydrogen is liberated at the tantalum electrode I45, I prefer to direct the flow of hydrogen to a point of combustion thereof, to prevent pollution of the ambient air.

Although I have illustrated herein only one man- I her of disposing of the hydrogen generated as an incident to generation of the desired flow of oxygen, it is to be understood that the hydrogen may be disposed of in any other suitable manner, as by conveying the same to astorage receptacle or the like (not shown).

As shown in Fig. 3, a second insulating member I49 is positioned upon and sealed to the upper surface of cover I43, the parts associated with said member being identical with those aforedescribed and functioning in a like manner. Thus theleft-hand chamber I49 contains a body of water I51 and the left-hand chamber I49 contains a body I58 of water. The hydrogen generated at the tantalum electrode I45 bubbles up through that portion of the liquid within separator I44, then passes in series through pipe I55, the body of water I51, pipe I56 and the body of water I58, whence it flows through conduit I59 to a chamber I69 where it mixes with the excess flow of blast furnace gas supplied to bleeder burner I 32 for combustion jointly with said excess gas, thereby insuring maintenance of the flame at said burner.

In a calorimetric device of the character disclosed in Figs. 2 and 3 I prefer to provide for testing of gases having a range of total heating values per unit volume of from 50 to 100 B. t. u. per cubic foot. Under these conditions the net heat input per cubic foot of air at full scale on the device is 16.43 B. t. u. The rate of delivery of air pump 21 is 13 cubic feet per hour. The net heat input at full scale is therefor: (13) (16.43), or approximately 213 net B. t. u. per hour. Therefore, the net heat input at any point on the scale will be the net heating value per cubic foot of the test gas, multiplied by 2.13, which corresponds with the number of B. t. u.

per hour.

17 amperes direct current flowing through the electrolyte in tank I42 will produce .125 cubic foot of oxygen per hour. Blast furnace gas requires ,75 cubic foot of air (which corresponds with .1575 cubic foot of oxygen) per B. t. u. The theoretical quantity of oxygen required for complete combustion of the blast furnace gas in a device like that of Fig. 3 corresponds with: (net heating value) (.0213) (.1575) or (net heating value) (.00336) cubic foot per hour.

The theoretical value of direct current amperes required for generation of the necessary quantity of oxygen is:

(Net heating value) (.00336) (17) (net heating value) amperes per hour, as indicated by the following chart:

Amperes for 535 335; theoretical l\et heating value quantity of oxygen supoxygen plied at 19 amperes Per cent 45. 7 41. 6 41. 2 46. 0 36. 6 52. 0 34. 5 55. 0

.By way of experiment I have found that in burning blast furnace gas of about 90 B. t. u. per cubic foot, with a current of 16 amperes direct current flowing through the electrolyte (affording 35 per cent. of the theoretically re-.

quired quantity of oxygen) there is a definite tendency of the burner flame to lift and go out. 19 ameperes direct current appears to provide the lowest rate of oxygen generation which will afford a satisfactory burner flame over a wide range of blast furnace gas heating values. I have likewise obtained satisfactory results by operating the oxygen generator with 28 amperes direct current, which will supply in the neighborhood of 75 per cent. of the theoretical quantity of oxygen required for complete combustion of the blast furnace gas. It is possible to still further increase the rate of generation of oxygen without encountering any operating difiiculties.

The foregoing data show that the addition of pure oxygen for primary mixture thereof with blast furnace gas, unlike the addition of primary air, activates combustion and increases the velocity of flame propagation. I have found in practice that forty per cent. or more of the theoretical quantity of air is required under conditions existing in the burner of a calorimetric device of the character shown in Fig. 3.

Referring again to Fig. 1, it is to be understood that if desired the upper end of conduit I60 may have applied thereto a blank cap (not shown), as a substitute for the cap containing the orifice or restriction I65, 50 that the supply of primary air for mixture with the flows of oxygen and gas is entirely eliminated, as in Fig. 3.

Although I have herein disclosed the use of my invention with particular reference to low quality gases, it will be apparent to those skilled in the artthatthe invention is likewise useful in effecting improvement in the combustion of, and consequently in the accuracy of the determination of the heating value of, combustible gases other than those of the low quality herein. mentioned.

I claim:

1. In the art of calorimetry of low quality combustible gases, the method which consists in effecting a continuous volumetrically constant flow of the low quality combustible gas, effecting continuous volumetrically proportional flows of air and substantially pure oxygen, effecting combustion of said flow of gas in the presence of said flows of air and oxygen, directly ascertaining the value of the temperature of the products of such combustion, utilizing said ascertained value as a measure of the total heating value per unit volume of said gas, the quantity of oxygen thus supplied being in excess of that required to effect complete combustion of said gas, and the quantity of inert gases in said air being insufiicient to cause-accidental extinguishment of the combustion flame.

2. In the art of calorimetry of blast furnace gas, the method which comprises effecting a 'continuous volumetrically constant sample flow of blast furnace gas, effecting a continuous volumetrically proportional flow of air, a portion of said flow of air being utilized as primary combustion air for mixture with said gas, said gas and air being supplied under like conditions of temperature, pressure and saturation, effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flows of gas and air for mixture with said gas and primary combustion air, the quantity of pure oxygen plus that in said primary combustion air being approximately sixty per cent. of the amount required to afford complete combustion of said gas, effecting combustion of said mixture of gas, oxygen and primary air in the presence of the remainder of said first mentioned flow of air, and directly ascertaining the value of the temperature of the products of such combustion, the quantity of inert gases, such as nitrogen, contained in said combustion air being insufficient to deleteriously affect the combustion flame.

3. In the art of calorimetry of blast furnace gas, the method which comprises effecting a continuous volumetrically constant sample flow of blast furnace gas, effecting a continuous volumetrically proportional flow of air, a portion of which is utilized as primary combustion air for mixture with said gas, said gas and air being supplied under like conditions of temperature, pressure and saturation, effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flows of gas and air for mixture with said gas and primary combustion air, said flow'of pure oxygen being supplied at a temperature corresponding to that of said flows of gas and air, the quantity of pure oxygen plus that in said primary combustion air being approximately sixty per cent. of the amount required to afford complete combustion of said gas, effecting combustion of said mixture of gas, oxygen and primary air in the presence of the remainder of said first mentioned flow of air, and directly ascertaining the value of the temperature of the products of such combustion, the quantity of inert ases, such as nitrogen, contained in the combustion fluids being insufficient to cause accidental extinguishment of the combustion flame.

4. In the art of calorimetry of blast furnace gas, the method which comprises effecting a continuous volumetrically constant sample flow ofv blast furnace gas, effecting a continuous volumetrically proportional flow of air, a portion of Which is utilized as primary combustion air for mixture with said gas, said gas and air being supplied under like conditions of temperature, pressure and saturation, effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flows of gas and air for mixture with said gas and primary combustion air, said flow of pure oxygen being supplied at a temperature corresponding to that of said flows of gas and air, the quantity of pure oxygen plus that in said primary combustion air being approximately sixty per cent. of the amount required required to afford complete combustion of said gas, effecting combustion of said mixture of gas, oxygen and primary air in the presence of the remainder of said first mentioned flow of air, and directly ascertaining the value of the temperature of the products of such combustion, the quantity of inert gases, such as nitrogen, contained in said primary combustion air being insuificient to cause accidental extinguishment of the combustion flame, ascertaining the value of the difference in temperature of said flows of gas, air and oxygen prior to combustion and the temperature of the combustion products, and utiliz ing said ascertained value as a measure of the totalheating value per unit volume of said gas.

5. In a blast furnace gas calorimeter of the gaseousfluid type, in combination, means for a effecting a continuous volumetrically constant sample flow of blast furnace gas, means for ef-' fecting a continuous volumetrically proportional flow of air, means for utilizing a portion of s'aid flow of air as primary combustion air for mixture with said gas, means for insuring like conditions of pressure and saturation of said flows of gas and air, means for effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flows of gas and air,

I said flows of gas, air and oxygen being supplied directly measuring the temperature of the combustion products, the quantity of nitrogen or other inert gases contained in the combustion fluids being insuflicient to deleteriously affect the combustion flame.

6. In a blast furnace gas calorimeter of the gaseous fluid type, in combination, means for effecting a continuous volumetrically constant sample flow of blast furnace gas, means for effecting a continuous volumetrically proportional. flow of air, means for utilizing a portion of said flow of air as primary combustion air for mixture with said gas, means for insuring like conditions of pressure and saturation of said flows of gas and air, means for efiecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flows of gas andair, said flows of gas, air and oxygen being supplied under like conditions of temperature, means for mixing said gas, primary air and oxygen, the.

quantity of pure oxygen plus that in said primary air being approximately sixty per cent. of

the amount required to afford complete combustion of said gas, means for effecting continuous combustion of said mixture of gas, primary air and oxygen in the presence of the remainder of said first mentioned flow of air, the quantity of nitrogen or other inert gases contained in that part of said flow of air which enters into the combustion being insufficient to cause accidental extinguishment of the combustion flame, means for continuously ascertaining directly the value of the difference in temperature of said flows of gas, air and oxygen prior to combustion and the temperature of the combustion products, and means for utilizing said ascertained value as a measure of the total heating value per unit volume of said gas.

7. In a blast furnace gas calorimeter of the gaseous fluid type, in combination, a burner, means for effecting a continuous volumetrically constant sample flow of blast furnace gas to said burner, means for effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flow of gas for mixture with the latter during passage thereof to said burner, means for effecting a continuous volumetrically proportional flow of air in the presence of which said mixture of gas and oxygen is burned at said burner, the quantity of oxygen present in said flows of oxygen and air being in excess of that required to effect complete combustion of said flow of gas, means for directly ascertaining the temperature of the products of combustion of said gas, oxygen and air, and the quantity of inert gases present in the combustion fluids being insufficient to have any substantial smothering effect upon the combustion flame.

8. In a blast furnace gas calorimeter of the gaseous fluid type, in combination, a burner, means for effecting a continuous volumetrically constant sample flow of blast furnace gas to said burner, means for effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flow of gas for mixture with the latter during passage thereof to said burner, means for effecting a continuous volumetrically proportional flow of air in the presence of which said mixture of gas and oxygen is burned at said burner, the quantity of oxygen present in said flows of oxygen and air being in excess of that required to effect complete combustion of said flow of gas, the quantity of inert gases present in said flow of air being insufficient to have any substantial smothering effect upon the combustion flame, electrical means for continuously ascertaining directly the instantaneous value of the heating effect of combustion of said flow of gas, and means for continuously utilizing said ascertained value as a measure of the total heating value per unit volume of said flow of gas.

9. In a blast furnace gas colorimeter of the gaseous fluid type, in combination, a burner, means for effecting a continuous volumetrically constant sample flow of blast furnace gas to said burner, means for effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said fiow of gas for mixture with the latter during passage thereof to said burner, means for effecting a continuous volumetrically proportional flow of air in the presence of which said mixture of gas and oxygen is burned at said burner, the quantity of oxygen present in said flows of oxygen and air being in excess of that required to effect complete combustion of said flow of gas, the quantity of inert gases present in said flow of air being insufficient to have any substantial smothering effect upon the combustion flame, electrical means for continuously ascertaining directly the instantaneous value of the heating effect of combustion of said flow of gas, and means for continuously utilizing said ascertained value as a measure of the total heating value per unit volume of said flow of gas, the aforementioned means including means for supplying said flows of gas, oxygen and air to said burner under like temperature conditions.

10. In a blast furnace gas calorimeter of the gaseous fluid type, in combination, a burner, means for effecting a continuous volumetrically constant sample flow of blast furnace gas to said burner, means for effecting a continuous flow of substantially pure oxygen which is volumetrically proportional to said flow of gas for mixture with the latter during passage thereof to said burner, means for effecting a continuous volumetrically proportional flow of air in the presence of which said mixture of gas and oxygen is burned at said burner, the quantity of oxygen present in said flows of oxygen and air being in excess of that required to effect complete combustion of said flow of gas, the quantity of inert gases present in said flow of air being insufficient to have any substantial smothering effect upon the combustion flame, electrical means for continuously ascertaining directly the instantaneous value of the heating effect of combustion of said flow of gas, and means for continuously utilizing said ascertained value as a measure of the total heating value per unit volume of said flow of gas, the aforementioned means including means for supplying said flows of gas, oxygen and air to said burner under like temperature conditions, said last mentioned means also including means for insuring like pressure and saturation conditions of said gas and said air.

CLARENCE S. PINKERTON.

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