US1605946A - A cospobation - Google Patents

Description

J. C. HAYES, JR 'HOT BLAST sTovE INSTALLATION 2 Sheets-Sheet '1 Filed April 10. 1925 SDN QCM Nov. 9, 1926.

1,605,946 J. c. HAYES, JR

HOT BLAsT sTovs msTALm-rou Filed April 1o. 1925 2 sheets-sheet 2 figg.

Patented Nov. 9, i926.

i r r JOHN U. HAYES, JR., OF CHCAGO, ANY, 0F CHICAGO,

Application led April 10, 1925.

The present invention relates to hot blast stove installations.

More particularly the present invention relates to installations involving hot blast stoves for blast furnaces. It is common practice to burn the blast furnace gas from blast furnaces in hot blast stoves, said gas being washed prior to admission to said stoves. The washing of the gas entails a heat loss, and the use of the washed gas also is apt to give rise to a deposit 'of a mixture of lime and alkaline salts. This deposit is more pronounced on settings with small combustion space than with modern settings. Unless the gas is dried, the gas mains have to be flushed regularly to clean out the sludge baked on the nozzles andv The entrance of unevaporated apertures. water mist into the burners has the effect, even in modern settings, of lowering the possible iiame temperature very materially.

For the purpose of illustration a plant may be assumed in which the gas from blast furnaces is washed for bot-h stove and boiler use. rlhe gas coming from the washer` at 72 degrees Fahrenheit is 'saturated with water vapor or steam. rlhe amount of vaporized water at the above temperature may be taken to be 11.7 grains per cubic foot. The gas must, of course, be saturated, because it enters the washer at 300 degrees Fahrenheit carrying about 30 grains of vap'orized water per cubic foot. In addition to a water vapor content corresponding to' saturation, it contains excess moisture in the forniof small water globules or mist, which is carried over from the sprays in the gas washer and also condensed from the gas itself as the vapor in the gas is cooled down in the washer. The 11.7 grains of moisture is steam. The moisture in excess of saturation at the temperature of the gas is unevaporated water and vapors from 0.5 to 2.0

grains per cubic foot. This water must beA evaporated, so that its latent heat, as well as specific heat, is a detriment to combustion and lowers the flame temperature both in the stoves and in the boilers. The decrease in iiame temperature due to evaporation may amount to 10() degrees Fahrenheit or more.

Thek present invention contemplates the provision of means for drying the washed blast furnace gas pri-or to the admission of said washed gas to the stoves.

Serial No. 22.242.

An object of the present invention is to provide a blast furnace installation of the type in which the blast furnace gas is burned in the hot blast stoves, which installation will have the advantage that the formation of sludge y0r other deposit will be minimized.

A. further object is to provide an improved system in which washed blast furnace gas will be effectively dried before being admitted to hot blast stoves, whereby the efficiency of said stoves will be very materially improved over present practice.

A further object is to provide an installation of the type in which blast furnace gas is burned in hot blast stoves, in which installation the exhaust gases from said stoves will be used for drying the washed blast furnace gas before said blast furnace gas is admitted to said stoves.

A further object is to provide a blast furnace system in which the washed blast furnace gas may be readily controlled.

A further'object is to provide an improved installation in which blast furnace gas is used for supplying the hot blast stoves, which installation will simplify the job of determining the location of leaks if any leaks should occur, of making repairs, and of by-passing the blast furnace gas in case any part of the installation should have to be shut down for repairs.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure 1 is a diagrammatic representation of a blast furnace installation embodying the principles of the present invention;

Figure 2 is a view of a gas heater and drier used in the installation shown in Figure 1; and Y Figure 3 is a vertical sectional view taken along the` plane indicated by the arrows 3 3 of Figure 2.

Referring first to Figure 1, the numeral 1 indicates a blast furnace, from whicl blast furnace gas is conducted through the conduits 2-2 to the dust catcher 3. Said dust catcher 3 has communication with the gas washer 4.- through the conduit 5, which may be controlled by the valve 5. The gas washer t may have associated therewith the water seal 7 for preventing the backflow of gas in case the blast furnace is shut down. A conduit 8 controlled by the valve 9 prollt) vides conimunication between the gas washer l1 and the water seal '7. Leading from the water seal 7 are a pair of conduits 10 and 11, of which the conduit 10 Vis controlled by the valve 12 and the conduit 11 is controlled by the valve 13. Said conduit 10 communicates with the conduit 14, which leads to tric boiler A conduit 15, controlled by the valve 15", is provided for by-passing blast furnace gas directly from the dust catcher 3 to conduit 10, when such by-passing required.

The conduit 11 vvprovides communication between the water seal 'Tand a gas drier and heater indicated asa whole by the numeral 16. Said drier 16 has the function of drying the which has been washed, whereby to prevent the deposit of sludge, as above referred to, and whereby to evaporate any entrained moisture in said gas. A conduit 17 leads from the drier 16 and has communication with the conduit 14 leading to the boiler 15, and also has communication (by way of conduit 17El controlled by the `valve 17) with the conduit 18, which connects with the blast stoves 19-19 through the pi es E20-20. A flue 21 conducts products o combustion from the hot blast stoves 19--19, said flue being `connected to the drier 16 through the conduit 22. As will be referred to hereinafter, the hot products of combustion from hot blast stoves are used for providing heat to dry the clean gases passing through said drier 16. After the products of combustion from the hot blast stoves 19-19 lhave performed their heating functions in the drier 16, they are conducted through the conduit 23 to the stack 24. The conduit 17 is provided with the valve 25 for stopping the flow of clean gas from the heater 16 to the conduit 18 when desired. The conduit 23 may be shut off from the stack 24 by means of the valve 26. Communication between the flue 21 and stack 24 may be controlled by the valve 27. The valve 28 is provided in the conduit 22 to control the How of products of combustion to the heater16 for heating purposes.

The details of one form of heater 16 will now be described. The type of heater shown in Figures 2 and 3 comprises an enclosure 29 provided with the tubes 30-30. Said tubes connect with the chambers 31 and 32, of which the chamber 31 is supplied by the conduit 11 and of which the chamber 32 delivers gas to the conduit 17. Said chambers should be provided with manholes, whereby access may be had to the tubes d 3() for the purpose of cleaning said tubes. Said chambers are also provided with the drains 34, through which dirt may be removed.

Hot products of combustion from the hot blast stoves 19H19 are admitted to the enclosure 29 by way of the conduit 22. Said hot products of combustion take a oircuitous path through said enclosure 29, being di rccted along` said circuitous path by the baffle 35. The conduit 23 provides communication from the interior ot' the enclosure 29 to the stack 2st.

During normal operation the valves 6, 9, 13, 17C, 25, 26 and 28 are open, and valves 12, 15b and 27 are closed. Under these conditions gas from the blast furnace may pas.;` through the gas washer 4, water seal 7, conduit 11, tubes B9- 30 of the heater 16, and 4pipe 17. From here part of the gas may pass to the boiler .15 and the remainder et the gas may pass through the conduit 16 to the hot blast stoves 19- -19. Products of combustion from the hot blast stoves 19-19 pass-through the conduit 22 to the interior of the enclosure 29 of the heater 16. Heat from said products of combustion is cornmunicated to the clean gas within the tubes {lO-30, eilectually drying said gases and `communieating' sensible .heat thereto. lVhen the `heater 16 is to be shut down, as, for eX- ample, for cleaning or repair, the valves 13, 25 and 26 will be closed and valve 12 `will bc opened, whereby gas may be directed from the dust catcher L1 and water seal 7 through the pipe 10 to the boiler 15 and to the hot blast stoves 19-19 'Vhen it is desired to cut out the Washer f1 and Water seal 7, valves 6 and 12 may be closed and valve 15b opened, under which conditions gas will be directed through the conduit 15 to the conduit 10.

By reason of the present invention sludge is deposited from the blast furnace gas before it gets to the burners of the hot blast stove. `Said sludge is deposited in the drier 16, which is easily cleaned, or is carried along in the Aform of dry dust in ythe gas current. The installation according to the .present invention offers an improved etliciency over present practice, inasmuch as the burners in the stoves may be kept in good condition for relatively long periods of time, so that the time `consumed in shut downs is very materially reduced. The entrance of unevaporated water mist in the gas as it enters the combustion chamber is also very materially reduced.

Though a preferred embodiment of the present invention has been described in detail, it will' be clear that many modifications will occur to those skilled in the art. It is intended to cover all such modifications that fall within the scope of the appended claims.

lVhat is claimed is:

1. An installation including a blast furnace, hot blast stoves, means for conducting blast furnace gas from said blast furnace to said stoves, said means inelhdnga drier for said gas,..an`d means for conducting hot products of'combustion from said hot rblast stoves to said drier.

2. An installation comprising a blast furnace, hot blast stoves for said furnace, means 'for conducting blast furnace gas from said blast vfurnace to said stoves, said conducting means including a drier for said gas for causing,` the deposit of sludge and for raising the sensible heat of said gas, said drier being arranged for convenient cleaning, and means tor conducting products of combustion from said stoves to said drier.

S. In combination, a, blast furnace, hot blast stoves lor cooperation with said furnace, a pair of parallel paths for conducting blast furnace gas from said furnace to said stoves, one ot' said paths including a drier for said gas, and means for conducting hot products oi" combustion from said stoves to said drier for drying the gas in said stoves and for raising the sensible heat thereof, said drier being capable of ready cleaning, and valve means for controlling said parallel paths.

4. Means for improving the eliiciency of blast furnace installations, comprising, in

combination with the usual blast furnace,

hot blast stoves and a heater for the gas delivered from said furnace to said stoves, said heater being readily cleanable and being heated by products of combustion from said stoves.

Signed at Chicago, illinois, this 7 day of April, 1925. i

JOHN C. HAYES, JR.

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