USRE20046E - Process for treating sewage or - Google Patents

Description

y 1936. H. J. HARTLEY Re. 20,046

PROCESS FOR TREATING SEWAGE OR SIMILAR MATERIAL,

Original Filed Aug. 17, 1934 Air INVENTOR fl Ifi M I BY ATTORNEY Reissued July 28, 1936 MAT Henry J. Hartley, Hastings-upon-the-Hudson,

N. Y., asslgnor to Nichols Engineering and Research Corporation, New York, N. Y., a corporation of Delaware Original No. 2,015,052, dated September 17, 1935, Serial No. 740,250, August 17, 1934. Application for reissue June 3, 1936, Serial No. 83,316 Claims. (01. 110-15) Preferably, the material to be treated is ground in suitable manner to break up the large pieces My invention relates to processes for treating sewage, or the like material, the invention being particularly adapted to the treatment .of sewage.

In accordance with the invention, the gaseous products resulting from combustion of such material are withdrawn from'the furnace chamber after passage through the combustion zone thereof to thereby greatly decrease or substantially eliminate the noxious or objectionable odors in said gaseous products of combustion.

Various other objects, advantages and characteristics ofmy invention will become apparent from the following description.

My invention resides in the process, process steps, system, and features of the character hereinafter described and claimed.

For an understanding of my invention and for A an illustration of one of the forms my'apparatus may take, for carrying out the invention, refer ence is to be had to the accompanying-drawing, in which:

The figure is a vertical sectional view, partly in elevation, of a furnace arrangement as constructed and arranged in accordance with my invention.

As shown on the drawing, F represents any suitable furnace or combustion chamber such, for example, as a multiple hearth furnace of the Herreshoif type. As is well understood,'a furnace of this character comprises a plurality of superposed hearths surrounded and supported by the usual furnace wall structure. As illustrated, the hearth arrangement is such that a plurality of hearths l and 2 are provided, a'hearth 2 being disposed between each pair of hearths I, each hearth -i being provided with a central opening la, each hearth 2 being provided withone or more outer openings 2a, and all of the hearths being secured in and supported by-the furnace wallstructure 3.

Extending axially through the center oii-the wall structure 3 is a suitably journalled, vertical rotatable shaft 4 which may be provided with radially extending rabble arms 5 utilizable for rabbling the material over each of the hearths in succession down through the furnace. As

disclosed in Herreshoff U. S. Letters Patent No.

976,175, November 22, 1910, the'central shaft 4 and the rabble arms .5 may define conduits through which a cooling medium is adapted to circulate. In other respects, the usual design of furnaces of this general type may befollowed and if desired, the furnace arrangement may be of the general type disclosed in U. S. Letters Patent No. 1,669,925, May 15, 1928.

andthen filtered to remove such quantities of moisture as may readily be disposed ofin that manner. Upon completion of this operation,the.

material may befed intoa hopper 6 from which a screw conveyor I, or equivalent, serves to transportthe material so that it drops down through a conduit 8 which terminates interiorly of the furnace F From the conduit 8, the material falls upon the uppermost hearth I' and is rabbled inwardly by the teeth on the upper rabble arm 5 so that said material passes downwardly through the opening la of the upper hearth and thereby reaches the uppermost hearth 2. On the hearth last named, the material is rabbled outwardly by therabble arm which coacts therewith, the mate'rial eventually dropping from said hearth 2 through the openings 2a at theedge thereof. In this manner, the material to be treated or in- .,cinerated is rabbled alternately inwardly and outwardly across the superposed hearths of the furnace, the material dropping through the inner opening of one hearth to the' next lower hearth and, after passage there'acro'ss, dropping .through the openings at the periphery thereof so as to reach the periphery of the hearth therebeneath.

The material, as it passes downwardly through the furnace, is first driedand then incinerated, the operation last noted occurring principally in the lower area of the furnace. It will be understood that air is necessarily supplied to the interior-of the furnace for the purpose of supporth ing combustion. In accordance with my invention, such air is admitted into the furnace at or adjacent the top thereof and withdrawn from said furnace in the region of the bottom thereof, the air, therefore, passing downwardly through the furnace in the same general direction as is taken by the descending sewage materialunder treatment.

The arrangement for causing the air to move downwardly through the furnace in the manner last described may be of any suitable character. To this end and as herein shown, a pipe or condult 9 is so positioned that it opens into the top 1 I and to be discharged to the atmosphere, if desired. The products ofcombustion which are nace chamber and this is maintained during continued operation of the fan I I.

With the furnacein operation, combustion of the descending sewage material proceeds on one or more of the lower furnace hearths. Ordinarily, the gases evolved from the material under treatment would rise through the furnace but, as stated above, the fan It establishes a downdraft stream of air. Therefore, this'air s'tream together with the evolved gases necessarily passes through the above noted combustion zone and it is in this zone that the temperature is at a maximum interiorly of the furnace chamber.

It results, therefore, due to the high temperature obtaining in said combustion zone and further due to the presence of atmospheric air which previously had entered the furnace chamber that the hydrocarbon content of the gases evolved by heat treatment of the sewage material are largely or substantially entirely burned. Accordingly, the gaseous material which passes to the atmosphere through the conduit I is largely or substantially free from noxious gases which, if present, would cause annoyance to persons in the vicinity.

I From the viewpoint-30f eificlency and economy, it is desirable for the hot gases passing from the furnace chamber to be brought into heat-exchanging relation with respect 'to the stream of air passing toward-and into said furnace. This feature of the invention is illustrated on the drawing which shows a long section of the inlet pipe 9 as disposed interiorly of a corresponding section of the outlet pipe II). By virtue of this relation, it is obvious that the gases passing to the top of the-furnace chamber by way of the pipe 8 are pre-heated by the hot gases passing through the pipe [0. In lieu of a heat-exchange arrangement of the character shown. it is to be understood that any other suitable type of arrangement may be utilized for accomplishing this hearths on whichpccurs the principal combus-' tion of thesewagematerial. Under such conditions, it will be understood that the invention is not to be limited-to the passage of atmospheric airv from the pipe I, or equivalent,'into the top of the furnace chamber. As well, .under some circumstances, this air may be introduced into said furnace chamber nearer the middle thereof although it will be understood that it is advantageous for such air to pass along a path of extended length while in contact with the sewage material so as to more effectively dry the same.

As shown on the drawing, one or more gas or oil nozzles l2, or equivalent, may be associated with the furnace chamber so as to supply addi- V 'tional heat above the lower hearth or hearths.

The heat obtained from these sources may be utilized at any time when the furnace is to be placedin'operaticn and, under some circumstances. it may be desirable to utilize such heat some chamber.

sources intermittently or continuously so as to obtain such number of heat units in the combustion zone as may 'be required to efliciently bum the sewage material and maintain the temperature of such zone sufliciently high to eliminate the hydrocarbon vapors of the gaseous products of combustion which are passed therethrough. It will be understood that any other suitable heat source may be substituted for those described immediately above and, further, it will be understood that such'heat sources may be disposed either interiorly or exteriorly of the furnace chamber as desired. 7 I

As shown, the shaft 4 carries a lower gear l3 with which meshes a second gear l4 operated by a suitable motor I! or other equivalent device. With the motor l5 operating, the sewage material descending through the pipe 8 passes along a circuitous path downward through vthefumace Such material is temporarily retained on eachofthe hearths while being advanced thereacross, the material, on each hearth I being moved toward the shaft 4 and, on each hearth i,

spectivehearths 2. As a result, the sewage mate-,

rial is dried in an effective manner in the upper furnace regions and as such material descends through the furnace, it becomes progressively.

drier. bustion of the dried material is completed and, under proper operating conditions, it results that such material becomes principally an ash by the time it reaches the lower hearth from which it may be removed through a suitable conduit l8 or the like. v

Under some circumstances, it'may be desirable to treat the moist material on the upper On one or more of the lower hearths, comhearth or hearths with one stream of air, preheated or otherwise, and to treat the dry and burning material on the lower hearths with anremains substantially odorless and hence may lbe passed to the-atmosphere without obj'ction. The second'named stream of air becomes, odorladen, however, and it is this air stream which is that my novel process is especially advantageous,

useful and efficient because depending principally or entirely upon the heat generated by combustion of the sewage material for the elimination of noxious odors from the hydrocarbon gases. The expense of the complete operation is substantially decreased while, at the same time, the amount of equipment is decreased in comparison with the equipment required by prior art arrangements for accomplishing the same end. 15

respect to certain particular preferred examples which give satisfactory. results, it will be under-- While the invention has been described with stood by those skilled in the art after understanding the invention, that various changes and downwardly through a plurality of superposed zoneswhile first drying and then burning themodiflcations may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new anddesired to be secured by Letters Patent is:

1; The process .of treating sewage or similar.

material, which comprises passing said material same, temporarily retaining said material in each of a plurality of said zones, moving said material horizontally through each or said zones by the application of a series of successive rabbling impulses thereto, passing a stream of-air downwardly through said zones along the path of travel of the material at each of said zones successively, whereby the'gaseous products of combustion produced with said air are made substan- -[tially free of noxious odors in passing through the lower of said zones where burning occurs, discharging said products of combustion from the lowermost zone by suction, and subjecting said air prior toits introduction to the uppermost zone ,to heat interchanging relationship with the exit gases from said lowermost zone.

,2. The process of incinerating sewage mate-' rial to form an ash and evolved gases free ofnoxious odor, which comprises first treating the material to remove therefrom a substantial portion'ofthe moisture content thereof, then -passing. said material downwardly through a plurality of superposed zones whilefirst drying and then burning the same, temporarily retaining said material in horizontal layers at each of said zones while periodicallyagitatihg and advancing it through each zone and gradually from zone to zone, said drying being effected by introducing a stream of preheated air into contact with the material at the zones of drying, and passing said stream of air downwardly from said drying zones along the path of travel of the material through the zbnes-of burning, whereby the gases evolved from the drying material and thegaseous products of combustion are heated at the zones of 4 burning, to a high temperature for the substan-.

tial elimination of noxious odors therefrom.

3. The process of inclnerating sewage material to form an ash and evolved gases free of noxious odor, which comprises first-treating the material to remove therefrom a substantial portion of the moisture content thereof, then passing said material in' succession through a plura'lity of'superpo'sed zones, themat erial being admitted into the top zone and passed downwardly from zone to zone, drying the materialdurlng its passage through an upper zone or zones, and burning the material during its passage through lower zones, temporarily retaining said material in substantially horizontal layare at each of said zones-while periodically agitating it and gradually advancing it through each zone and causing it to drop from zone to zone,

said drying being effected by introducing a stream of preheated air into contact with the material at said upper zoneor zones of drying,

passing said of air through thedrying zone or zones in extended contact with said layers and then into-and through the lower zones of burning, whereby the'gases and vapors evolved from the drying'material'as well as the gaseous products of combustion evolved at the burning zones are ,heated-in the zones of buming, to. a high temperature for substantial elimination of noxious odors therefrom, and preheating said stream of air .for introduction at said zone or zones of drying by bringing such air into heat interchanging "relationship with the hot gaseous products from the burning zones. 4. The process of incinerating sewage material to form an ash and evolved gases free of noxious odor, which comprises first treating the material to remove therefrom a substantial portion of the moisture content thereof, then passing said material in succession through a pluralityof' superposed zones, the material being admitted into the zone, drying the material during 'its passage through an upper zone or zones, and burning the material during its passage through lower zones,

temporarily retaining said material in s'ubstan- 2 tially horizontal layers at each of said zones while periodically agitating it and gradually advancing 20. 'top zone and passed downwardly from zone to it. through each zone and causing it to -drop from a zone to zone, said drying being effected by introducing a stream of preheated air into contact with 30 the material at said upper zone or zones of'drying, and passing said stream of, airthrough the drying zone or zones in extended contact with said' layers and then into and through the lower zones of burning, whereby the gases and vapors evolved from the drying material as well as the gaseous products of combustion evolved at a burning zones are heated in-the zones of burning,- to a high temperature for substantial elimination of noxious odors therefrom. v

5. The process of incinerating sewage material to form an ash and evolvedgas'es free of noxious odor, which comprises first treating the'mate q rial to remove therefrom ansubstantial portion of the moisture content thereof, then passing said material in succession through a plurality of superposed zones, thematerial being. admitted into the top zone and passed downwardly from zone to zone, drying the material during its passage through an upper zone or zones, and burning the material during its passage. through lower zones, temporarily retaining said material as a-- layer at each of said zones while periodically agitating it and while it is gradually'advanced through each zone, said drying bein'geffected by introducing a stream of preheated air into extended contact with said. layers of material at stream of air from the drying zone or zones intoand through the lower zones of burning, the gase- 60 f ous products of combustion and vapors evolved from the'material being then withdrawn through substantially the hottest burning zone, to insure of their being subi'e'ctedbefore their exit, to a.

high temperature for substantial elimination of 5-.

obnoxious odors therefrom, and preheating said stream of air prior to its introduction into the zone or zones of drying by bringing such air into heat interchanging relationship with the hot withdrawn gases andvapors.

HENRY J. HARTLEY- said zone .or zones of drying, then passing -said-

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