US2242089A - Means for making mineral wool - Google Patents

Description

May 13, 1941. c. F. RAMSI-:YER

MEANS FOR MAKING MINERAL wooL Filed Aug. l5, 1958 '3 Sheefts-Sheet l May 13, 1941. c. F. RAMSI-:YER 2,242,089

MEANS FOR MAKING MINERAL WOOL Filed Aug. l5, 1938 3 Sheets-SheetI 2 May 13, 1941. c. F. RAMSEYER ,2,242,089

MEANS FOR MAKING MINERAL WOOL Filed Aug. 13, 1938 3 Sheets-Shea?l 5 E N l.

Patented May 13, 1941 t' UNITED STATES PATENT OFFICE MEANS Fon. MAKING MINERAL wool. Charles F. Ramseyer, Chicago, ll. VAmflication August 1s, 193s, seriaiNo. 224,829

(ol. r9- 53) l 3 Claims.

the quantities of fuel required. Further, the4 mineral wool produced Was not always uniform because of the` lack of accurate control. The only method heretofore employed for controlling the temperature, viscosity and chemical content of the material has been by changing the ratio of rock or slag to the coke charge in the cupola, or by varying the composition of material added to the charge, and since in most plants lt is a matter of hours before the materials charged in at the top of the cupola can influence the temperature or composition of the material coming from the tap hole, it will be seen that such control of the molten material and the mineral wool formed therefrom is very far from being either instantaneous or automatic.

In my copendlng application Serial No. 67,868,

filed March 9, 1936, I have disclosed-,andi claimed a novel method of and means of making mineral wool which includes a wet-bottom coal-fired boiler, which is an oxidizlngfurnacef, and means for handling the fused coaly ash slag as it comes from the boiler and maintaining the-slag in the f proper temperature and viscosity condition sult- 4 able for forming mineral wool, thus utilizing a waste material without previous value and producing a superior grade of mineral wool of uniform quality. One of the features materially contributing to the, successful attainment of these results is the provision of a novel condily there is considerable foaming and gassing at v the tap hole, due to reactions resulting from is the provision of means whereby the molten coal tioning furnace construction, disclosed andv claimed in my copending application, Serial No. 217,397, led July 5, '1938, which receives the molten coal ash slag from the boiler and controls the temperature and viscosity of the slag so as to maintain the material in a state best adapted to facilitate the formation of mineral Wool there` ash slag can be freed of all gases before it reaches the tap hole, whereby there is no tendency to foam and gas when the slag is tapped'of and led into the conditioning furnace. More specifically, it is a feature of this invention to provide a degassing zone in aboiler offthe continuous slag tap type and holdthe molten slag pooled in the de-gassingv zone of the continuous slag tap boiler until foaming has terminated, so that the molten slag will flow freely and readily into the conditioning furnace in a more or less steady stream, preferably while maintained at a relatively high temperature to insure the continued fluidity of y the de-gassed slag.

t ,wool therefrom;

Figure 2 is a section, somewhat -diagrammatically shown, taken along the line 2 2 of Figure l, showing one form of slag pooling baiile;

Figure 3 is an enlarged vertical section taken generallyalong the line 3-3 of Figure 2, showing 'one means for heating the slag as it flows from the boiler slag spout;

Figure 4 is an enlarged section taken along the line 4-4 ofFlgure 3;

Figure 5 is a plan view, largely diagrammatic,

of a modified form of slag pooling baffle;

Figure 6 is an enlarged section takenalong the line 6-6 of Figure 5;

Figure 9 is a fragmentary view of the outer end aaiaos of the l"baille, being a view taken along the line f.

8-8 of Figure 7.

Referring first to the boiler shown in Figure 1, the furnace is indicated in its-entirety by the ref erence numeral I and comprises suitable walls 2 of refractory material. which may be water cooled, as indicated by the upper headers 5 and 6 and the lowe headers 1 and 8. Vertical gridsconnect the headers 5, 1 and 8, 8 so as to provide for the desired flow of cooling water to reduce the temperature o`f and protect the refractory material forming the side walls 2, as in the usual.

practice. The bottom of the furnace is indicated at |8 and is in the form of a relatively shallow trough having a slag opening II. The bottom wall I8, like the side walls 2, is formed of refractory material and is cooled by a. grid extending between the lower headers 1 and 8 and the inner headersV I3 and III. The steam gen-A erating unit of the boiler is indicated at 28 and haslongitudinal tubes 2| and a cross drum 22, disposed above the combustion space C of the boiler I.

'I'he pulverized coal used for fuel is supplied through a conduit 25 to a pulverizing mill indicated at 26. Air is supplied for combustion from a draft fan (not shown) which forces air downwardly through a conduit 28, an air heater 28, and conduits 38 and 8| to a duct or wind box 32 from which the air ows through a duct 33 to a nozzle 34. Also, a branch duct 36 leads from the wind box 32 to the pulverizing mill 26, and a suction pipe 31 leads from the pulverizing mill to the inlet side of a blower 38. The latter draws air in through the pulverizing mill 26 and forces both the air and pulverized coal through a conduit 39 to an inner nozzle 48. From the space C the gases of combustion are passed over the boiler tubes 2| and through a breeching v42 and an economizer 43, and then'through the air heater 28 to an induced gas fan (not shown) yThrough a duct 44, from which they are released to atmosphere or otherwise disposed of.

extend a substantial distance along the furnace bottom and away from the slag hole and the ends of the baille sections 5| and 52 are turned. inwardly, as 5Ia and 52a, the inturned ends being spacedV apart by a small distance, indicated at 13.

in Figure 3 by the reference numeral 18 and The slag spout of the boilerA I is best indicated consists of a passage 11 lined with suitablerefractory.` The lower portion of the spout may have a cooling water jacket 18 with suitable inlet and outlet connections, not shown. The outlet of the slag spout is indicated at 18 and has a port 88 adjacent which is a gas burner 8|. Another gas burner 82 is provided adjacent the lower edge or legs 83 of the slag outlet 18. An opening4 84 closed by a block 861s formed in the outer portion "of the spout 16 to provide for an inspection of the-spout end when the block 85 is removed. The flames from the burners 8| and 82 keep the molten slag at the proper temperature and prevent it from freezing.

The conditioning furnace which receives the molten slag is indicated at 88,*and for a more detailed description of this unit reference may be had to my copending application mentioned above. It will therefore suffice to state that the vconditioning furnace comprises a suitable refractory container 8| 'supported on a frame 82 and provided with sets of water cooled electrodes 93 and 84 by which the temperature and viscosity.

of the molten charge in the furnace are maintained at thedesired value. The furnace 88 is arranged for tilting about an axis lso as to direct a small now of molten slag onto a suitable wool forming means, such as a spinning disc or jet of steam or air under pressure.

f- The molten slag from the furnace is delivered to the conditioning furnace 88 through al slag runner indicated in its entirety by the reference numeral |88 and which includes a relatively stationary section I8| and a swingable section |82 disposed adjacent the furnace I and movable relative to the section |8I into and .According tothe principles of the present invention the bottom I8 ofthe furnace is provided with a slag baille indicated in its entirety by the reference numeral 58. The slag baille consists of two sections 5| and 52 (Figure 2) disposedon opposite sides of the slag. tap hole Il, and each Tsection consists of a loop Iof pipe the upper bar 55in diverging relation and are arranged to receive refractory material 64. The lower bars 6|'.of each baille section are secured to the furnace oor in any suitable manner, and the bars 6| are protected by refractory material 6l, as shown. Suitable conduits 61 and 68 are connected to the outer ends of thepipes 55 and and extend outwardly through the boiler wall 2. Connections 83 and 1| are provided to receive pipes by which cooling water is passed through 'the baille sections.

The ow of cooling water through the baille sections 5| and 52 effectively protects them from 'the high temperature of the molten slag. As best shown inFigure 2, the baille sections 5| and 52 proximately 1700 F. Considering a temperaout'of a position to receive the molten slag as it runs from the slag spout opening 18. Both runner sections |8| and |82 are made of refractory material and are generally hollow or tubular in form. Each runner section is provided with cooling coils indicated at and |88, respectively, the latter being especially constructed to accommodate the swinging action of the runner section or diverting runner |82. Also, the `runner sections are provided with suitable openings establishing points ofl communication with the interior of the slag channel in the runner and` heating means inthe form of gas burners or the like are mounted at thesepoints, indicated at |88 to for maintaining the slag heated to the proper degree. The cooling 'coils |05 and |86 keep the runner I 88 from getting too hot.

The purpose of heating the slag stream and, at the same time, cooling the slag runner, and also the slag spout 16 is. first, to keep/the slag at a sufilciently high temperature, usually around 2500 F., so that it flows readily. and second, to keep the refractory at a sufficiently low temperature that it is not melted, dissolved or carried away by the molten slag. Usually the temperature of refractory should not exceed apture gradient line from the center of the slag stream to the cooling means, the cooling water being generally around 60 F., the point on the gradient line corresponding to 1700*' F. deterrelease sulphur gases.

mines the contour'or -srface of the runner, since .if the slag is hotter, portions of the refractory will be melted down to a point where there is sufficient cooling to reduce the temperature to 1700" F., and if the slag is cooler then some of the slag freezes, itself becomingva part of the refractory and building up the latter to a point spaced inwardly of the cooling means and sufflciehtly close to the center of the molten slag that the temperature is 1700` F. It is to be understood that these values are merely illustrative.

In the operation of the boiler, the molten ash resulting from a combustion of the fuel collects on the side and bottom walls of the furnace and flows toward the slag hole Due to the slightly different conditions in various parts of the furnace during operation, as mentioned above, the portions of molten slag coming from different parts of the' furnace do not all have exactly the same chemical composition, and heretofore vthese dierent portions yof molten ash did not meet or come together until just before or at the slag tap hole This results in gassing and foaming at this point, since slags of different composition reacted with one another, generally to The molten slag became lled with tiny bubbles of gas which changed the consistency and characteristics of the slag and produced a material which did not flow readily.

According to the principles of the present invention, the baille sections 5| and 52, with the small entrance opening 13, provide a .construction in which all reactions between the slag portions from various parts of the boiler take place at a point well within the boiler where the temperature is high and the reactions thereby hastened.' Hence, by the time the slag has reached the ,tap hole all foaming and gassing has stopped and the 'slag flows as a free liquid with practically all gas removed. In other words, the baille sections 5| and 52 set up or establish a de-gassing pool within the boiler, and the surface of pool defined by the bailies 5| land 52 is of suflicient extent that all reactions within the pool are completed before the molten slag reaches the slag spout and flows toward the conditioning furnace.

While in Figures 2 and 3 I have shown the degassing pool formed by the baiiies as at one end of the boiler, it is to be understood that the degassing pool -may be placed wherever desired or necessary. For example, it may be formed at one side of the boiler, as at or adjacent the 'right hand wall vin Figure 1, if there should be any tendency for foam forming material to fall from the fiames of the burners 40 into the degassing pool, which would be undesirable.'

Another form of slag baille is shown in Figures 5 to 9. In these figures Vthe boiler is indicated at la and has walls 2a and a slag tap hole ||a in the bottom |a of the boiler relatively closely adjacent a wall 3a. In this case the baille.

indicated in its entirety bythe reference numeral l In this form of the invention, the slag tap hole' a is surrounded by a ring |20 which consists of a number of loops, preferably three, of pipe |2|, the upper of which enters a water-cooled spout |23.. and the other two of which, as indicated at |25, are placed in a position closelyadjacent the furnace floor [0a so as 'to providea lip |23 over which the slag within the baille 50a flows through the slag tap hole lla.' The pipe loopsv |2| are provided with bars |23, |29, and |30 which are J :oextensive with the pipes |2| and arev securely welded or otherwise fastened thereto. Short bars |3| (Figure 8) are welded to the lower pipe |2|. Water is circulated through the loops and through the spout |23 by means of an inlet and outlet connections |33 and |34., If desired, the bars |28, |29 and |30 and the loops |2| spout |23. The circulation of the cooling water through the connections |33 and |34 and the pipe loops |2| prevents the high temperature of the molten slag from affecting the loops |2| or bars |28, |29 and |30.

The baille 50a is constructed similarly to the ring |20. The baille 50a consists of a coiled loop of pipe or conduit having three sections |4|, |42 and |43 connected together by bars |44 securely Welded t the pipe loops IM, |42 and 43. Inlet and outlet connections |5| and |52 extend through the furnace walls 3a, like the connections |33 and |34, and one leads through the pipe section |4| (Figure 7) around'to a return bend |53 (Figure 9) which is welded to Ithe ends of the pipes |4| and |42. The pipe |42 extends lsame around -to the point where it connects to the other connection |52. ,A lower bar |51 is welded to the pipe |42 and also to the furnace floor grid, preferably but not necessarily in the manner shown in Figure 8, and the bar |51vis of .varying height to permit vthe baille to lie level While accommodating the slope of the furnace floor, as shown in Figure 6. 'I'he return bend |53 is disposed from the adjacent portion of the baffle 4by a relatively small amount, as indicated at |50 inFigure'l.

A bar |6| is welded in place between the return bend |53 and the adjacent part of the baille, providing what might be :termed a weir over which the slag from diierent portions of the furnace flows in entering between the convolutlons ofthe baille 50a. At this point the various reactions take place which may result in foaming, gassing and the like, but the relatively long distance of iiow which this slag is required to follow before it reaches the ring spout sets up a'de-gassing pool and provides a sumcient opportunity for all of these reactions toV progress to completion before the molten slag reaches the spout |23. The flow of cooling water through 'the connections |5| and |52 and around the pipe loops |4|, |42 and |43 prevents the baille from being damaged by the high temperature of the molten slag, and if desired, the

baille may be covered by refractory material,

although I have found that this is not necessary since some of the slag may freeze on the baiiie and act itself asa refractory. In operation, the slag ows continuously around through the baille 50a and out the ring spout |20. The reactions that take placewithin the de-gassing pool established by the baffle` are hastened by .the heat within the furnace itself, and the disposition of the spout Ila in the furnace floor makes it unnecessary to supply slag spout heating means, as in Figure B." When the4 boiler is operated but the slag is not used for making mineral wool, the slag drops into a water chamber |85 (Figure 6), but when the slag is to be used for making mineral wool, the water chamber |65 is replaced by a slag runner, such as the construction shown in Figure 1.

-secure the desired amount of gas removal.

While I have shown and described above preferred constructions and methods of operation, it is to be understood that my invention is not to be limited tothe details shown and described above but that, in fact, widely different means may be employed in the practice of the broader aspectsl of my invention.

What I claim, therefore, and desire to secure by Letters Patent is: l y

1. The combination with a wet--bottom boiler having a slag tap opening, of means for establishing a degassing zone comprising a slag ring surrounding said opening and having a spout discharging into said opening, a slag baille of generally spiral formation having one end disposed molten slag before the latter reaches the slagtap opening.` Y A 2. The combination with a wet-bottom boiler having a slag tap opening, of baille means dening aspace about said tap.. opening\and having an inlet opening remote from said tap opening, saidl baille means being arranged so that all of the slag is required to flow -through said inlet opening into said space where a pool of the same is formed in which any reaction of the slag that may take place is substantially completed before it ows out of saidtap opening.

3. In a furnace of the Wet-bottom type having a slag tap and utilizing pulverized coal as a fuel, means for segregating a. relatively small portion of the slag bottom by two baiiles secured to the furnace bottom with the ends converging so as to form a slag pool with two restricted openings one of which constitutes-an inlet through whichall of the slag in the bottom must flow and the other of which discharges through said slag tap, said slag pool being of suiiicient length and area as to enable any slag reaction caused bythe co-mingling of various portions of the slag from diierent parts of saidk slag bottom adjacent said inlet to be substantially completed by the time it flows out of said slag tap.

CHARLES F. RAMSEYER.

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