US2504508A - Magazine furnace and method of burning fuel having a low sintering temperature - Google Patents

Description

Apnl 18, 1950 G. E. EDLING 2,504,508

MAGAZINE FURNACE AND METHOD OF BURNING FUEL mwmc; A LOW smmmc TEMPERATURE Filed Nov. 13, 1944 OQOQOOOQO Patented Apr. 18, 1950 UNITED STATES PATENT ()FFICE MAGAZINE FURNACE AND METHOD or BURNING FUEL HAVING.A LOW SIN- TERING TEMPERATURE Gustaf Emanuel Edling, Stockholm, Sweden, assignor to David Dalin, Ostertalje, Sweden Application November 13, 1944, Serial No. 563,299

- In Sweden November 11, 1943 Claims. (Cl. 122-237) (Granted under the provisions of sec. 14, act of l March 2, 1927; 357 0. G. 5) 2 This invention relates to a method and device the invention constructed in accordance with the for producing heat carrying combustion gases best mode so far devised for the practical apand combustible gases from fuels of granular or plication of the principles thereof, and in which:

other suitable shapes and sizes and has for its Figure 1 is a vertical sectional view through a purpose accomplishing such combustion and gas 5 combustion apparatus embodying this invention; generation with a high degree of efficiency and Figure 2 is a detail vertical sectional view on reliability. An important feature of this invenan enlarged scale through part of one wall of the tion is that the fuel consisting of solid pieces of fuel shaft, taken at one of its air inlets; and

- one or more walls, which are cooled in a suitable the walls of the shaft.

various sizes and shapes is made to burn and give Figure 3 is a detail view similar to Figure 2 oil combustion gases and combustible gases while illustrating another manner of restricting the lying in a vertical or nearly vertical shaft having air inlet openings between the tubes defining manner. The fuel is preferably piled to consid- Referring now more particularlytothe drawing. erable height in the shaft, and the latter, in rereference numeral I shows an infeed funnel for a latlontoits height, is comparatively narrow. Sevsolid crushed or granulated fuel, such as, shale r l adv nta es are ained by this arrangement, coke, for example. At the lower end of this funfor instance, the combustion temperature can be 'nel the fuel assumes an exposed surface at 2 effectively controlled by means of the cooled walls according to its angle of repose, from where it in the shaft and by using tubes which are filled descends successively into the small'upper part with a flowing medium such as water or steam for go 4 of a vertical fuel shaft 5 which at its lower end the cooled walls, the excess heat of combustion is equipped with a suitable outfeed device 6 for can be usefully utilized, for instance, 'for the the ash and slag. As is clearly shown on the generation of steam and superheating of steam drawing the shaft 4 and 5 is high but relatively which in turn can be used for power generation. narrow.

The invention can be used with advantage for all At one side of the funnel I there is a gas chamkinds of fuels, but is particularly valuable in deber 1 with air inlets 8 and 9. The part ll of the vices for burning of waste products such as garfunnel l which faces the gas chamber I is a cooled bage and other burnable oifal and for fuels with wall, preferably consisting of tubes through which a low melting or sintering temperature such as flows a medium such as water or steam. The coke remaining from shale and slate distillation 3o botto of the tube wall In joins with a movable and for burning Cir/and distillation Oleaginous shutter II also constructed of tubes for water or shale. steam, and a similar shutter 12, likewise made In heretofore known furnac s f r bur fu s from similar tubes, is installed in the outlet opencontaining ash which melts at a low temperature, 111g [3 leading from the gas chamber 1 to the considerable difliculties are experienced-because i b ti hambe l4, 15,

the t p a u n the fuel e if an economi- The shaft 4, 5 has similar cooled walls which cally advantageous excess of combustion air is to preferably are d f om tubes [-6 which are be used for the combustion-gets so high that the filled it flowing medium (water or steam) ash melts and ba e o r resulting in excesand connected toheaders (water or steam chests) slve slag and incomplete utilization of the fuel. or the like t By the use of the method and device of this In Figures 2 d 3 it is clearly shown that invention, the above described disadvantages are there i a id abl distance between the eliminated a fuels having an ash with 10W tubes [6. These tubes are like the tubes l 0 shown melting of sintering temperature can be burnt horizontally disposed, but vertical or slanting with a. high degree of utilization in, for instance, t b or t b ith othe configuration can also the generation of steam at such a temperature be used that the ash and sl w ll n m It i t The walls in the combustion chamber is are possible to effectively utilize such fuels and offal l ed ith ater or steam tubes I! or heretofore Considered as Wastecooled by other means. On the drawing the With the above and other objects in view Which tubes I1 are shown vertically disposed and con- Wi pp as h rip n pro d thi innected to headers I a. From the space I! located vention resides in the novel construction, comb l th b sti n hamber 15 collected soot bination and arrangement of parts substantially and h can be eadil removed, as hereinafter described, and more particularly c b ti air i itt d through th passage efi d y the pp C m it being u 20 from a fan, for examp1e,.and flows through and stood that such changes in the precise embodi a oss, the lower part of the shaft 5, which is me t of e hereindisclosed invention may be filled with ash or slag, into the distribution chainmade as c me wi hin he s p of the claims. ber, 2|. From this chamber 2| the air flows The accompanying drawing illustrates one com through openings regulated by the shutters 22 plete example of the physical embodiment of v$0 through and across the shaft 5 approximately in a horizontal direction and out into the chamber l5. The combustion gases rise upwards in this chamber and pass thereafter through and across the narrowest part of the shaft 4 into the chamber l4 and from there through the passage 23 to a steam boiler 24 or other heat exchanger. Chamber 2| is further equipped with an inlet 25 for admittance of gases, for example combustion gases or water vapors, for the purpose of diluting the combustion air and thereby modifying the intensity of the combustion gases. By means of a fan or the like, the passage 25 may be connected with the combustion gas outlet from the steam boiler 24, so that a part of the escaping combustion gases are led through the passage 25 and thus made to circulate through the whole combustion device.-

At the openings opposite the shutters 22 the tubes l6 are equipped with flanges 26 or similar protuberances in a manner shown in Figure 2. These flanges 26 can be directly welded to the tubes l6 and be so shaped that they prevent the fuel from falling out between the tubes I6 but allow the combustion air to pass. The spaces between the shutter openings have the tubes l6 covered by plates 21 which are welded to or in other suitable manner attached to the tubes as shown in Figure 3, for the purpose of preventing the air from passing through the zones thus cov ered. By this means the air stream is forced to flow from the distribution chamber 2| to the chamber l in a more or less horizontal direction across and through the fuel shaft 5.

An air inlet opening 28 connects the distributing 1 burnt if desirable for completing the combustion,

process. This part of the combustion is regulated by adjusting the cooled shutters ll, i2 in various positions and furthermore in the usual manner by regulating the combustion air coming through the inlets 8 and 9. -The shutter H is thus adjusted to such a position that the temperature of the fuel does not rise above the most desirable degree having in mind the nature of the fueland the purpose of the process. By means of the shutter ii! the flow of the gases from the chamber 1 to chamber I4 is regulated. In some cases it is desirable to admit a certain regulated quantity of secondary air to the chamber I 4 for example through the opening 28 in order to there burn the gases from the chamber 1.

If the fuel at 2 is directly exposed to the radiation from the burning gases or to radiation from the surrounding brick-work in chamber I, the gases escaping from the fuel in the funnel I will also be consumed by combustion.

After the fuel has thus been preheated and degassed it passes downwards into the shaft 4 and 5 and is successively burnt. In the lower'part of the shaft the ashes and slag are removed through the outfeed apparatus 6. By regulating the speed of the outfeed device the speed with which the fuel moves downwards through the shaft 4 and 5 can be easily and effectively regulated.

The combustion air, either cold or preheated, coming through the passage 2|] passes first throu h the ash chamber in the lower part of the shaft 5, thereby cooling the ashes or slag while being itself heated. The thus heated combustion air after having passed through the ash chamber into the distributing chamber 2| passes through the openings at shutters 22 across and through section 5 of the shaft to effect combustion of the fuel contained in shaft 5. If complete combustion is desired, the final combustion will take place in the chambers i5 and I4, whereby if required the necessary amount of secondary air will be added through the inlet opening and another opening 29. The combustion gases resulting from the combustion in the shaft 5 pass into chamber l5 and from there through and across part 4 of the shaft, whereby they dry and. heat (eventually also ignite) the downwardly slowly moving fuel. If the device is used for steam generation the combustion gases can pass through the channel 23 to the steam boiler 24. If the device, on the other hand, is used as a gas generator, the gas escapes through the channel 23 for further use in other devices (not shown).

In certain cases it is, desirable to let only a part of the gases pass through the upper part 4 of the shaft. The remaining part of the gases is then led in another direction, for example direct in the gas) is economically unprofitable.

The combustion in the fuel shaft 4 and 5 occurs while the fuel is in more or less direct contact with the cool-walls of the shaft, that is with the tubes Hi. The fuel is therefore subjected to. the cooling effect from these walls while the combustion takes place and by this means it is possible to control and regulate the temperature of the fuel bed as desired. If, for instance, the fuel consists of coke from oleaginous shale or other similar fuels having an ash with low melting or sintering temperature, the cooling effect is regulated in such a manner that the ash will not melt and cause the fuel to cake together, thus allowing a complete and uninterrupted combustion of the fuel. A further regulation of the combustion temperature is possible by diluting the combustion air with some suitable gas such as spent combustion gases or water vapors which are admitted through the passage 25. If in this manner combustion gas containing a high percentage of carbon dioxide (CO2) is admitted to the channel 25 the carbon dioxide is broken down to carbon monoxide (CO) in the shaft 5, thereby consuming heat with a resulting lowering of the temperature in the shaft. Breaking -down of the water takes place in a similar manner, if water vapor instead is admitted through the passage 25. It is even possible to admit, through the passage, only an inert gas such as nitrogen for direct dilution of the combustion air, so that the combustion intensity and thereby also the tempera ture in the shaft 5 is reduced. A portion of the combustion gases from the steam boiler 24 can also eventually be returned by means of a fan to the passage 25 so that these combustion gases circulate within the apparatus and only receive so much addition of fresh combustion air from the passage 20 which corresponds to the combustions requirement of oxygen. From the above it will readily'be seen that the combustion in the shaft 5 can easily be regulated in desired manner.

This regulation of the combustion results in a high utilization of the fuel and a very eillcient combustion process. This result is largely due to the fact that the burning of the fuel can proceed uninterrupted without the formation of largecakes of slag and because the heat transmission from the fuel in combustion to the tubes l6, I1, "-42 is very effective, whereby the flowing medium in the tubes, preferably water or steam, is effectively heated. The tube systems I0, l2, I6, I1 can therefore with advantage be used for steam production or for steam superheating. 1

Certain modifications in the above shown and described device can easily be made within the scope of this invention. For instance the walls in the shaft 4, 5 or in the combustion chamber l5 can be cooled by other means than by tubes. One or more walls in the fuel shaft 4, 5 may be cooled but preferably all walls should be cooled. The gas chamber 1 may be entirely eliminated. In the chamber IS a convected heating surface may be installed.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A combustion apparatus especially adapted for the burning of fuels having low sintering temperatures comprising: means defining an upright fuel shaft in which the fuel is held during combustion thereof, said means including fluid cooled surfaces defining opposite walls of said shaft, said surfaces having air spaces therebetween through which air may flow into and out of the shaft; means defining a combustion chamber at one side of said shaft and with which the shaft interior connects through the air spaces in the adjacent shaft wall; means defining an air dis tributing chamber at the opposite side of the shaft, said air distributing chamber being connected with the shaft interior through the air spaces in the adjacent wall of the shaft and terminating short of the top of the combustion chamber; means defining an exhaust flue above the air distributing chamber, said exhaust flue having communication with the top of the combustion chamber and the interior of the upper portion of the shaft through the air spaces in its opposite walls; means defining an inlet for combustion air, said inlet leading to the lower portion of the shaft'at the side thereof remote from the air distributing chamber so that the combustion air must pass through the lower portion of the shaft to reach the distributing chamber; and means for deflecting combustion air rising within the distributing chamber laterally through the shaft and into the combustion chamber for subsequent passage to the exhaust flue.

2. The hereindescribed method of burning fuel having a low sintering temperature, in a furnace having a well defined fuel passage leading from a fuel inlet to a grate; and having fluid ducts in juxtaposition to the fuel passage and at such relative spacing that all portions of the burning fuel are close to some part of the ducts, which comprises: feeding fuel of low sintering temperature to the fuel passage; igniting the fuel so as to cause the same to burn in the combustion zone above the grate; supplying combustion air to the fuel in said zone in such volume as to 1 bustion in suflicient maintain a high rate of combustion; continuing the feeding of fuel to the fuel passage as the fuel burns away; and circulating a fluid coolant through the fluid ducts in such volume as to keep all portions of the burning fuel at a temperature below the sintering point of the fuel.

3. The hereindescribed method of degassing and subsequently burning fuel having a low sintering temperature in a furnace having a well defined vertical fuel passage leading from a fuel inlet at its top, through a degassing zone and a combustion zone above a grate; and having tubular fluid ducts in juxtaposition to the combustion zone of the fuel passage and at such relative spacing that all portions of the burning fuel are close to some part of the ducts, which comprises feeding fuel of low sintering temperature into the fuel passage through its inlet to pass through the degassing zone to the combustion zone; igniting the fuel in the combustion zone above the grate to cause the same to burn and provide heat for driving of gases from the fuel in the degassing zone; drawing off the gases released from the fuel in the degassing zone; supplying combustion air to the fuel in the combustion zone in such volume as to maintain a high rate of combustion; continuing the feeding of fuel to the fuel passage through-its inlet as the fuel burns away; and circulating a fluid coolant through the tubular fluid ducts in such volume as to keep all portions of the burning fuel at a temperature below the sintering point of the fuel.

4. In the process of burning fuel having a low sintering temperature, the step of circulating fluid heat absorbing medium in juxtaposition to, but not in contact with, fuel in the zone of comvolume and quantity to maintain the temperature of the fuel in said zone below the sintering temperature thereof.

5. The method of burning fuel having a low sintering temperature, which comprises: confining the fuel to a defined zone for combustion; supplying air to the fuel in said zone in such quantity as to assure optimum conditions for rapid combustion of the fuel; circulating a fluid coolant along defined paths in juxtaposition to, but not in contact with the fuel within, the combustion zone to carry off heat energy from the burning fuel; and so regulating the flow and quantity of the fluid coolant as to assure the dissipation of enough heat energy from the burnin'g fuel to preclude sintering of the fuel.

GUSTAF EMANUEL EDLING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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