CA1119983A - Enriched fuel making and sewage treating process - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Particulate coke and raw sewage are mixed and conveyed as a slurry through series connected, pressure sealed chambers into which super-heated steam is injected to convert the mixture into a molten mass depleted of noxi-ous gases and volatiles. The molten mass is compacted while exposed to reactive hydrogen gas to form an enriched solid fuel log.

Description

This invention relates to the treatment of sewage and enrichment of solid fuels, and is related to the subject matter in my prior U.S. Patent No. 4,02~,040.
~ ccording to my prior patent, the treatment of sewage and various hydrocarbon solids is dealt with in connection with the production of various petrochemical products. In general, steam is mixed with the raw feed under controlled temperature and pressure conditions effecting release of gases and volatiles therefrom, and a solid residue recovered.
The prior art also discloses apparatus utilized in such processes~
including the conveyance of slurries by bottom-mounted augers through horizontally elongated chambers into which steam is injected. Such prior apparatus and processes have been utilized for disti]ling hydrocarbons from granula~ materials such as wood or extraction of oil from oil shale and sand. The treatment of solid fuels such as coal and coke is also disclosed, including its hydrogenation and the removal of sulphur compounds therefrom.
The use of such apparatus and methods as aforementioned for enrichment of low energy content, solid fuels by treatment with raw sewage has not been fairly taught until now, and it is therefore an important object of the present invention to provide apparatus of the aforementioned type specifically adapted for the simultaneous treatment of raw sewage and enrichment of so]id fuels. The foregoing objective is especially important in vlew of the present awareness of ecological deterioration caused by untreated sewage and the need for alternatlve sources of fuel.
It :Ls therefore another object of the present invention to provide an economical method of making an enriched Euel from relatively inexpensive and waste materials.
Broadly, the present invention provides a method oE treating raw sewage and enriching a relatively low energy content solid fuel, ~0 comprising the steps of: grinding said solid fuel into particles; mixing said particles with the raw sewage to form a slurry; mixing the slurry during movement with super-heated steam until volatile by-products are evolved therefrom, leav.ing a liquid depleted mass; exposing said mass to a reactive gas other than steam; and compacting said mass into a solid fuel product.
In one embodiment of the present invention, a relatively low energy content fuel such as particulate coke is mixed with raw sewage to form a slurry that is conveyed through series connected chambers maintained at desired temperature and pressure conditions by injection of super-heated steam into the chambers. The slurry is conveyed through the cham~rs by bottom mounted augers having clearance from the walls of the chamber to accommodate mixing and agitation as well as collection of evolved gases and volatiles that are removed and passed through a condenser for recovering non-noxious f].uids~ .

~ 0~- \ -la-including oil, gas and water. A liq~id deple~ed residue is then ¢onduc~ed from the mlxing chambers into a packing unit into whlch reactive hydroge~ gas is injected. The residue or mass introduced into the packing unit ls compacted in order to form a solid fuel log. A packing ~Dlt such as tha~ disclosed in my prior U~S. Paten~ ~o. 4,028,040, aforemen~ioned, may be utili~-ed for this purpoqe.
Figure 1 is a si~plified block diagram illustrati~g the ~ethod of the present invention.
Figure 2 is a block dlsgram showing the arrangement of apparatus for c~rrying out ~he method.
Flgure 3 i8 a side eleva~ional ~iew with parts broken away and shown in sec~ion of certain components of ~he apparatu~ diaBra~med in Figure 2, Y18ure 4 i8 ~ transverse section view taken substantially through a plane indicated by section line 4-4 in Figure 3.
Referring now to the drawings in detail, Figure 1 diagramma~ically depicts the method of the present inve~tion which i~volve~ coke frol~ a suit-able source 10 and raw sewage ~rom a source 12 that are mixed within a slurry mixer generally referred to by re~erence numeral 14. The coke i8 ground by a grinder 16 i~to particulate for~ prior to being mixed with the raw sew~ge ior the purpose o~ the prese~ inven~ion. SupRr-heated steam from a ~ource 18 ls supplied to the ~ixer 14 ln order to es~abli~h predetermlned temperature and pre~3ure conditions within the mlxer necessary to effect conv~r~ion of the sewage into a ~orm capable of ultim~tely enriching the coke arld releasing non-~oxiou~ 8aRes ~nd volatiies. The actual temperature and pressure condi~ions will depend on the content o the sew~ge and i~8 establishment by control over the superheated steam is well within the capabilitie3 of those skilled in the art. A liquid-deple~ed re~idue or m3,83 iS accordingly dlscharged fro~ the ~nixer lnto a compactor stage 20 into which a reactlve gas such a3 hydrogen is injected from source 22. The mass ~upplied to the compactor 20 i~ in a mnlte~
state and i8 converted into a solid fuel lvg by compaction and cooling as dis-closed for example i~ my prior U.S, Patent No. 4,028,040, aforementioned.

As shown i~ Figure 2, the ~lurry ~ixer stage 14 includes ~hree mix-ing units 243 26 a~d 2B, interconnec~ed so as ~o e~ble feed oi the slurry ln serles therethrough. A co~tinuous feeder 3G into which the partlculate coke and 3ewage is charged, ~uppl~es the slurry to the firs~ mi~ing u~it 24. The slurry is conveyed horizontally through the mixing unit 24 from one axial end at inlet 32 to the other axial end at ou~let 34, from whiGh the slurry is gravitationally discharged into the second mixing unit 26. The slurry is con-veyed in the opposite direction through the second mlxing unit and discharged gravitationally into the third mixi~g unit 28 from which a molten re~idue is discharged at final outlet 36 in~o the packing unit 20 as aforementioned. The fuel log product is obtained from the packing unit 20 while volat~les are dis-charged therefrom. The non-noxiou~ gases evolvad fro~ the ~lurry wlthin ~he mixing units i~ collected thxough a gas outlet 38 and pa~sed throu~h a ~on-denser 40 to discharge a condensate in the form of water and hydrocarbon fl~id~.
As re clearly seen in Figures 3 and 4, each of the mixing u~lts 24, 26 an~ 28 are si~ilar in cons~ruction and operation to each other, except for the direc~ions of feed. The uppermost and lowermost mixing unit~ 24 and 28 are operative through auger-type devices 40 to pull the slurry through horizon~al pre~sure sealed chambers. The auger de~ices 40 are driven by speed synchronized electric motors 42 connected to tubular auger shafts 44 on ~hich the spiral flights 46 of the ~uger devices are mounted. The ~uper-heated 3te~m is introduced i~to the chamber or mixing ~ones ~hrough openings 48 formed within the tubular shat~ 44. As will be ob~erved from Figure 4, the tubular sha~t ~ is rotatably mounted in eccentric relation to the longitudinal axin of ~he uni~ housing and the auger fligh~s 46 mounted thereon are dimen-sioned so a~ to provide ~uf1cient clearance 50 ad~acent the bottom of the chamber to enable the rota~ing auger device to adequate}y mi~ and agitate the ~lurry 52 being fed through the chamber. The clearance above the auger device 40 i8 ~u~cient to enable forma~ion of a gas spa e 54 within which ~he non-noxiou3 gas and volatiles are collected and removed through the g~s outlet 38 as aforementioned. The foregoing relationship of the auger device to tha mix-i~g chamber e~ables the slurry to be acted upon by ~he super-heated ~eam and under the pre~ailing tempera~ure and pressure conditions to evenl:ually dis-charge fro~ ~he inal unit 38 a suitable molten mass or residue.

The reaction of the molten mass wi~& the hydrogan gas within the packing un$t 20 has been found to produce under compact:Lon pres~ure ~ solid fuel log that is free of se~age contamination and has a significan~ly higher en~rgy content than ~he cok~ introdu¢ed into the process.

Claims (7)

The embodiments of the invention, in which an exclusive property or privilege is claimed, are defined as follows:

1. A method of treating raw sewage and enriching a relatively low energy content solid fuel, comprising the steps of: grinding said solid fuel into particles; mixing said particles with the raw sewage to form a slurry;
mixing the slurry during movement with super-heated steam until volatile by-products are evolved therefrom, leaving a liquid depleted mass; exposing said mass to a reactive gas other than stream; and compacting said mass into a solid fuel product.

2. The method of claim 1 wherein said low energy content solid fuel is coke.

3. The method of claim 2 wherein said reactive gas is hydrogen.

4. The method of claim 1 wherein said reactive gas is hydrogen.

5. The method of claim 1, wherein said slurry is conducted through a plurality of pressure sealed zones in series during mixing; physically agitating the slurry during movement through said zones; and cooling the com-pacted mass upon formation of the solid fuel product.

6. The process of claim 5, wherein said slurry is conveyed through the zones by forced feed flow.

7. The process of claim 5 wherein said volatile by products are water vapor and hydrocarbon gases.