US2793599A - Method and apparatus for improving combustion in boilers and the like - Google Patents

Description

May 28, 1957 c. PEAK 2,793,599

METHOD AND APPARATUS FOR IMPROVING COMBUSTION IN BOILERS AND THE LIKE Filed June 20, 1952 /2 I I I l I l /6'Z E E I I I 1 44 48 I 1 46 i ,6 i v INVENTOR. f i 2 E awn/ass PfJqK 20 I I I i 6855M 1 {'"K q MO 1 U1 u Arrokf/ys United States Patent METHOD AND APPARATUS FOR IMPROVING COMBUSTION IN BOILERS AND THE LIKE Charles Peak, Amsterdam, N. Y., assignor, by direct and mesne assignments, of one-sixth to Roy J. Weiss, Detroit, Mich, one-sixth to Samuel Morrison, Buffalo, N. Y., one-sixth to William Byrne, New York, N. Y., one-sixth to James E. Haggerty, one-sixth to Edgar D. Flintermann and one-sixth to John M. Kisselle, all of Detroit, Mich.

Application June 20, 1952, Serial No. 294,660

Claims. (Cl. 110-1) This invention relates to a method and apparatus for improving combustion in boilers and the like.

It is generally well known that the production of a dense smoke and the formation of slag, flyash, and the like in furnaces results from inefficient combustion and incomplete burning of the fuel. It is also generally well known that, if substantially all the combustible matter in the material being fired can be burned before it escapes from the stack, the production of objectionable smoke is eliminated and the efliciency of the burning operation is increased.

There have therefore appeared on the market at var ious times in the past many proprietary products which have been recommended as being desirable for the purpose of eliminating smoke and soot. These products have been in the form of both solid and liquid chemical compositions adapted to be introduced into the furnace or boiler either by throwing them into the fire, mixing them with the fuel, or by other means. Throwing handfulls of chemicals on the fire periodically has not proved a satisfactory method primarily because beneficial results can be obtained only momentarily, that is only until the chemical is consumed. Mixing the chemical with the fuel has likewise proved unsatisfactory because the chemical does not become dispersed throughout the combustion chamber, flues, stack, etc. which is necessary toolstain complete combustion of all the combustible material in the fuel, including the tarry vapors formed in the distillation zone in the ease of a coal fire.

In the case of a liquid chemical it has also been proposed to introduce the chemical into the combustion chamber of a furnace or boiler by mixing the chemical with steam injected into the combustion chamber. This is undesirable for several reasons. In the first place, this arrangement tends to consume too much of the steam generated. In the second place it is impossible to produce the fineness of dispersion and the wide area of coverage necessary to insure a complete burning of the combustibles through the extent of the boiler.

Steam-air jets havealso been employed, primarily for the purpose of producing a greater turbulence of the g'ases over the fire bed and thereby obtain more intimate mixing of the combustibles with the oxygen in the air. This latter method may improve combustion and thereby somewhat reduce the formation of soot and smoke, but it 937:

does not remove sootfrom the boiler after it has been formed and does not improve the efliciency of the furnace or boiler to any great extent because of the amount of steam that is diverted for use with the jets.

It is an object of this invention to improve the combustion in a furnace or a boiler by introducing into the combustion chamber a very fine dispersion of chemicals. The chemicals are originally in the nature of a solid cartridge through which steam or moist air is caused to travel to thereby dissolve and/or pick up small particles of the chemicals and carry them throughout the furnace, flues and stack as a very fine dispersion in the nature of a colloidal suspension. The chemicals are generally of the type which reduce the combustion temperature of soot. I have found that, by providing throughout the boiler a ve'ryfine dispersion of chemical particles at all times, automatic control of combustion of soot and volatiles isobtained over a wide range of temperature.

The invention therefore contemplates a new arrangement for introducing combustion-improving chemicals into a furnace. The invention also provides a new chemioal composition for improving the combustion in a furnace or boiler and anew method for improving combustion in a furnace or boiler.

In the drawings:

Fig. 1 is a front elevation of a boiler provided with the combustion-improving apparatus of this invention.

Fig. 2 is a sectional view along the lines 2-2 in Fig. 1.

Fig. 3 is a fragmentary sectional view of the casing and the cartridge of chemicals within the casing.

Fig. 4 is a view of the chemical cartridge in side elevation.

Fig. 5 is a sectional View through the cartridge along the lines 5-5 in Fig. 4.

Fig. 6 is a fragmentary sectional view of a cartridge and a casing of modified construction.

For the purposes of description the invention will be described in connection with a coal-fired boiler. It will be appreciated, however that the invention is adapted for use with various types of furnaces and boilers. As a matter of fact, the inventionis usable in almost any combustion arrangement where soot,,smoke, slag, and/ or odorous fumes are likely to be produced. In Fig. 1 there is shown a coal-fired boiler generally designated 10 which includes a combustion chamber 12 having firebrick walls 14 and an access door 16. Above the combustion chamber 12 there is arranged a. boiler drum .18 in which steam is generated. The fire bed indicated at 20 is supported by a grate 22. Boilers of this general arrangement are common and the illustration is not in tended to represent any particular type of boiler.

In connection with the boiler illustrated, the apparatus of this invention includes a steam line 24 connected with a source of steam such as the drum 18 and provided with a valve 26 for controlling the flow through line 24. A generally cylindrical casing 28 isconnected at its upper end by means of a nipple 30 and union 32 with steam line 24. At its lower end casing 28 is connected by a nipple 34 and a union 36 with branch lines 38 connected with jets generally referenced 40. Each of the branch lines 38 has a control valve 42 therein for controlling the flow to the individual jets 40. The jets 40 each comprise a T fitting 44 having an air inlet 46 and opposed openings to one of which is connected a cylindn'cal pipe 48 which ex tends through the furnace wall 14 and the other of which is closed by a plug 50 through which a nipple 52 extends. Nipple 52 is adjustable inwardly and outwardly of T 44. In a conventional installation jet i0 is located about 12 inches above fire bed 22 and is directed downwardly at a slight angle towards the fire bed.

Within casing 28 there is arranged a cartridge of chemical-s 54. Cartridge 54 is cast or molded and fashioned with corrugated or fluted side walls 56 and end walls 58 :at least one or both of which are preferably also fluted. The cartridge is formed with a central axially 1' extending bore 60 and in some cases may be provided with a plurality of smaller circumferentially spaced bores 62. The cartridge is fluted or corrugated on its side and end walls to provide a maximum surface of contact between the cartridge and the steam flowing into the casing 28 through the nipple 30. The fluted construction also pernnts the steam to flow around the surfaces of the cartridge, that is, the fluted construction spaces the cartridge from the inner faces of casing 28. The bores 60 and 62 are provided for permitting a portion of the steam to flow directly through the cartridge so that when steam is permitted to pass through casing 28 it flows through and around cartridge 54 and makes intimate and direct contact with the cartridge as it flows to the jets 40. The steam thus picks up minute solid particles of the cartridge. These chemical particles are carried by the steam, which mixes with the air flowing into the jet through inlet 46, and discharged into the furnace by the steam-air mixture through the outlets of jets 40 as a very fine dispersion.

The quantity of air flowing through each jet can be varied by adjusting the nipple 52 inwardly and outwardly and by controlling the size of inlet 46. The steam pressure at the jet can be adjusted by valves 26 and 42. The steam pressure required is, of course, dependent upon the size and shape of the fire box and the load on the boiler. After the air supply is initially adjusted to a desired amount in a particular installation, the quantity of air is increased or decreased in accordance with the change in the pressure of the steam flowing through the jet. In an average installation a steam pressure of about pounds per square inch is suflicient. Thus, it will be readily appreciated that the amount of steam diverted is relatively small. I have found that on an average installation the amount of steam that is diverted through the jets 40 amounts to about only 2% of the total steam generated.

A very important feature of the present invention which has contributed greatly to the commercial success of the method and apparatus disclosed herein has to do with the cartridge 54, its shape, its composition. and its durability. The cartridge, of course, contains chemicals which are known to reduce the temperature of combustion of soot particles. Such chemicals include chlorides, lead and zinc salts, and salts of other metals such as manganese, copper, etc. The effectiveness of such chemicals to reduce the combustion temperature of soot is discussed in Bulletin 360, Removal of Soot from Furnaoes and Flues by the Use of Salts or Compounds. a bulletin of the United States Department of the Interior, Bureau of Mines.

The provision of a cartridge composed of such ohemical s alone is not satisfactory, however. The cartridge must include a basic ingredient which will form a somewhat porous but sound mass which serves as a carrier for the particles of chemicals. The basic material of the cartridge must be capable of being molded into the desired shape and must also be capable of withstanding the pressure of the steam directed therethrough so that the cartridge after continued use will not disintegrate into small chunks and plug up the steam line. The only material with which I am familiar that possesses these necessary qualities is portland cement; and of the several Portland cements manufactured, I have found that the Portland cement sold under the trade name of Medusa produces the most durable cartridges. Several examples of cartridge compositions are as follows:

Example I 12 ounces of water 12 ounces of sodium chloride (rock salt) 22 ounces of Portland cement Example I] 4 Example III 3 ounces of magnesium dioxide 3 ounces of sulphur 10 ounces of water 2 pounds, 10 ounces of Portland cement Example IV 6 ounces of water 6 ounces of chloride bleach 12 ounces of potassium chloride 1 ounce of sodium chloride (rock salt) 22 ounces of Portland cement Example VI As an alternative of the composition stated in Example V, the Water and chloride bleach may be replaced by 5/11 gallons of ammonia. A cartridge formed of this composition is adaptable for use in installations where it is desired to eliminate objectionable odors.

I have found that a cartridge about 3 inches in diameter and about 6 inches in height is of a very convenient size. In a typical installation where the steam pressure in the casing containing the cartridge is between 10 and 20 pounds per square inch, a cartridge of this size will operate efficiently to substantially eliminate soot, smoke, fiyash and slag for a period of about 30 days or 200 firing hours. A cartridge of this size and having a composition as set forth in the above example weighs almost 3 pounds. After being in operation for about 30 days or 200 firing hours, the cartridge will have lost about 1 pound in weight. At such time, the cartridge should be removed from the casing 28 and replaced with another cartridge.

In this connection a casing 60 such as illustrated in Fig. 6 is desirable, since its construction facilitates removal and replacement of the cartridge. The casing 60 has its lower end closed by a cover plate 62 which is removably secured to the casing as by bolts 64. At its upper end casing 60 is formed with an inlet 66 to which the nipple 30 may be connected, and at its lower end the casing is formed with a radially extending outlet '68 with which the outlet nipple 34 is connected. With this arrangement it will be observed that, whenever it is necessary to replace a spent cartridge with a new one, cover plate 62 is removed and the nipples 39 and 34 need not be disconnected. In the form of easing illustrated in Fig. 3 the casing comprises an upper half and a lower half threaded together as at 29, and replacement of a cartridge in casing 28 necessitates uncoupling of the steam line at the units 32 and 36.

As pointed out above the cartridge 54 is very sound and durable but at the same time it is sufficiently porous to permit steam, say at a pressure from about 10 to 20 pounds per square inch, to permeate therethrough and thereby pick up tiny particles of chemicals dispersed throughout the mass of the cartridge. The porosity of the cartridge depends to a large extent on the proportions of water and portland cement in the mix, the more water and less cement, the greater the porosity.

In installations where a pressure of less than 10 pounds per square inch is employed, it is sometimes desirable to use a cartridge which is more porous than the cartridge used with higher pressures. For example, in installations where steam is not generated, I have found that moisture-ladened air may be blown through the cartridge in place of steam. This may be accomplished by employing a blower and directing the air through humidifying means so that the air picks up from about 3 to 5 gallons of water per hour. With an arrangement of this type the pressure at the jet 40 may be as low as ounces per square inch, and under such circumstances, the cartridge used is preferably provided with about 9 of the bores 60, 62 therethrough and is shaped in the form of a cube, for example, 4 inches square and 3 inches high, to provide a substantial frontal area for contact with the moist air directed through the casing.

The type of jet 40 employed need not necessarily be of the type illustrated in the drawing. The jet should, however, have an air inlet for mixing air with the fluid stream flowing from the casing. For example, I have found that, when steam is directed into the combustion chamber without being mixed with air through the jet, the steam issues from the jet in the nature of a rod-like stream which simply shoots over the fire bed. However, when air is permitted to mix with the steam issuing from nipple 52, the stream issuing from the nozzle is highly dispersed, produces a fog-like turbulent vapor, and provides a blanket coverage throughout the combustion chamber, fines, etc. of the furnace of boiler.

Numerous tests and installations have shown that the apparatus herein described produces new and unexpected results. The apparatus not only eliminates the formation of soot and smoke but actually cleans surfaces on which soot, flyash and slag have already formed. The results produced by this apparatus may be explained partly by the fact that with the jets 40 in operation there is always present in the distillation zone over the fire bed and in other parts of the furnace or boiler a very fine dispersion of chemicals together with an adequate supply of secondary air for completely burning the soot particles and tarry vapors as they rise from the fire bed and travel towards the stack. The chemical dispersion is in the nature of a colloidal suspension, and the chemicals are present in an amount and over an area throughout the furnace or boiler such that they automatically go into action to complete the burning of the combustibles in the fuel throughout a wide range of temperature.

As an example of the effectiveness of this apparatus for improving combustion and the results actually obtained, the apparatus was tested on five locomotives equipped with stokers of four different types. The inlet line 29 in each case was connected with saturated steam at a pressure of about 75 pounds per square inch and thro'ttled down to about 10 pounds per square inch through the valve 26. The jets 40, two to each casing 28, were positioned at the door end of the fire box about 12 inches above the fire bed. With the apparatus thus arranged the steam was brought up to operating pressure in about sixteen minutes as compared with the usual forty-five minutes to one hour normally required on these locomotives without the apparatus of this invention. This reduction in the time required to bring the steam up to operating pressure can be attributed to the more complete burning and higher efficiency obtained with this apparatus.

The elimination of soot produces a better heat transfer, and I have found that the chemical dispersion also results in a much clearer zone above the fire bed which increases substantially the rate at which the radiant heat travels to the surfaces being heated. With the jets turned off, these locomotives produced a No. 5 smoke, and the smoke was reduced from a No. 5 to a No. 1 within thirty seconds after the jets were turned on. After operation for about ten minutes with the jets on, the smoke issuing from the stack of the locomotives was hardly perceptible.

Thus, it will be seen that I have provided a relatively simple but highly effective means and method by which combustion in a furnace may be greatly improved. The apparatus of this invention eliminates the formation of soot and smoke and produces a substantial increase in the efficiency of the burning operation. Inaddition, the arrangement herein described actually tends to clean surfaces on which slag, soot and flyash have already accumulated. Thus, frequent blow-downs for soot removal are eliminated and shutting down of the boiler or furnace for removing deposits of slag and the like are likewise rendered unnecessary.

This application is a continuation-in-part of my prior application Serial No. 51,291, filed September 25, 1948, now abandoned.

I claim:

1. An apparatus for improving combustion in a furnace and the like comprising a casing having an inlet and an outlet and containing a removable and replaceable cartridge, means including a conduit for directing a stream of moisture-laden gas of the nature of steam into said case in g through said inlet and conduit means connected with said outlet of the casing and extending into the combustion chamber of the furnace, said cartridge comprising a solid but porous body of set Portland cement containing uniformly dispersed therethrough and in'tergrally bonded therein, chemicals adapted to lower the combustion ternperature of combnstibles in fuel which would go off in smoke .in the absence of said chemicals, said chemicals including substantial portions of materials giving the effect of chlorine containing compounds selected from the group consisting of sodium chloride, potassium chloride, potassium chlorate and sodium hypochlorite, said cartridge being predominantly Portland cement and containing a substantial portion in the nature of one eighth to one-half of said chemicals based on the total weight of Portland cement and chemicals, said cartridge and said casing being of relative size and disposition to force the moving gas to intimately contact a relatively large surface of said cartridge, whereby said chemicals will be exhausted gradually and dispensed effectively.

2. An apparatus for improving combustion in a furnace and the like comprising a casing having an inlet and an outlet and containing a removable and replaceable cartridge, means including a conduit for directing a stream of moisture-laden gas of the nature of steam into said casing through said inlet conduit means connected with said outlet of the casing and extending into the combustion chamber of the furnace, and means for mixing an excess quantity of secondary air with said stream of gas, said cartridge comprising a solid but porous body of set Portland cement containing uniformly dispersed therethrough and integrally bonded therein, chemicals adapted to lower the combustion temperature of combustibles in fuel which would go off in smoke in the absence of said chemicals, said chemicals including substantial portions of materials giving the effect of chlorine containing compounds selected from the group consisting of sodium chloride, potassium chloride, potassium chlorate and sodium hypochlorite, said cartridge being predominantly Portland cement and containing a substantial portion in the nature of one eighth to one-half of said chemicals based on. the total weight of chemicals and Portland cement, said cartridge and said casing being of relative size and disposition to force the moving gas to intimately contact a relatively large surface of said cartridge, whereby said chemicals will be exhausted gradually and dispensed eifectively.

3. The method of dispensing chemicals for reducing the temperature of soot combustion which comprises mixing said chemicals with at least an equal quantity of Portland cement and water, setting said mixture in the form of a solid cartridge having some porosity and relatively large surface areas available for contact by other materials, enclosing said cartridge in a flow line leading to a combustion chamber and flowing a moisture-laden gas of the nature of steam through said line in contact with said surface areas of said cartridge whereby said chemicals will be dispensed at an effective rate while being exhausted at an extremely slow rate of speed, said chemicals including substantial portions of materials giving the efmasts;

fect of chlorine containing compounds selected from the group consistingof sodium chloride, postassium chloride, potassium chlorate and sodium hypochlorite.

4. The method of burning the smoke which would otherwise be emitted from a furnace and the like including a combustion chamber, which'comprises the steps of preparing a gas and. feeding said gas into said combustion chamber, the preparation of said gas comprising. the steps of introducing moisture into said gas, passing said moistore-laden gas over a dispensing cartridge containing soot combustion aiding chemicals and mixing secondary gas with said first gas to provide a fine dispersion of said chemicals to be led into said combustion chamber, said cartridge being a solid but porous body of set Portland cementjcontaining uniformly dispersed therethrough and integrallybonded therein, chemicals adapted to lower the combustion temperature of combustibles in fuel which would go oil. in smoke in the absence of said chemicals, said chemicalsincluding substantial portions of materials giving the effect of chlorine containing compounds selected from the group consisting of sodium chloride, potassium chloride, potassium chlorate and sodium hypochlorite, said. cartridge being predominantly Portland cement and containing a substantial portion in the nature of oneeighthto one-half of said chemicals based on the total weight of Portland cement and chemicals, whereby said chemicals will be exhaustedgradually and dispensed effectively;

5. "A cartridge adapted for dispensing chemicals to be fed with steam and the like to a combustion chamber of afurnace and the like comprising a solid but porous body having a relativelarge exposed surface in relation to its size and weight, said body comprising set Portland cement containing uniformly dispersed therethrough and integrally bonded-therein, chemicals adapted to lower the combustion temperature of combustibles in fuel which would go off in smoke in the absence of said chemicals, said 8 chemicals including substantial portions of materials giving the effect of chlorine containing compounds selected from the group consisting of sodium chloride, potassium chloride, potassium chlorate and sodium hypochlorite, said cartridge being predominantly Portland cement and containing a substantial portion in the nature of oneeighth to one-half of said chemicals based on the total weight of Portland cement and chemicals, whereby said chemicals will be exhausted gradually and dispensed effectively.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Removal'of Soot From Furnaces and Flues by the Use of Salts or Compounds, Bulletin 360, 1932, U. S. Dept. of Interior, Bureau of Mines.

Treatment of Coal Surfaces, R. A. Sherman et a1. Bituminous Coal Research Inc. (Reprint from Coal Preparation, 2nd Ed., American Institute of Mining and Metallurgical Engineers).

Claims (1)

1. AN APPARATUS FOR IMPROVING COMBUSTION IN A FURNACE AND THE LIKE COMPRISING A CASING HAVING AN INLET AND AN OUTLET AND CONTAINING A REMOVABLE AND REPLACEABLE CARTRIDGE, MEANS INCLUDING A CONDUIT FOR DIRECTING A STREAM OF MOISTURE-LADEN GAS OF THE NATURE OF STREAM INTO SAID CASING THROUGH SAID INLET AND CONDUIT MEANS CONNECTED WITH SAID OUTLET OF THE CASING AND EXTENDING INTO THE COMBUSTION CHAMBER OF THE FURNACE, SAID CARTRIDGE COMPRISING A SOLID BUT POROUS BODY OF SET PORTLAND CEMENT CONTAINING UNIFORMLY DISPERSED THERETHROUGH AND INTERGRALLY BONDED THEREIN, CHEMICALS ADAPTED TO LOWER THE COMBUSTION TEMPERATURE OF COMBUSTIBLES IN FUEL WHICH WOULD GO OFF IN SMOKE IN THE ABSENCE OF SAID CHEMICALS, SAID CHEMICALS INCLUDING SUBSTANTIAL PORTIONS OF MATERIAL GIVING THE EFFECT OF CHLORINE CONTAINING COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF SODIUM CHLORIDE, POTASSIUM CHLORIDE, POTASSIUM CHLORATE AND SODIUM HYPOCHLORITE, SAID CARTRIDGE BEING PREDOMINANTLY PORTLAND CEMENT AND CONTAINING A SUBSTANTIAL PORTION IN THE NATURE OF ONE EIGHT TO ONE-HALF OF SAID CHEMICALS BASED ON THE TOTAL WEIGHT OF PORTLAND CEMENT AND CHEMICALS, SAID CARTRIDGE AND SAID CASING BEING OF RELATIVE SIZE AND DISPOSITION TO FORCE THE MOVING GAS TO INTIMATELY CONTACT A RELATIVELY LARGE SURFACE OF SAID CARTRIDGE, WHEREBY SAID CHEMICALS WILL BE EXHAUSTED GRADUALLY AND DISPENSED EFFECTIVELY.

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