USRE19791E - Apparatus for treating gases - Google Patents

Description

Dec. 17, 1935. A. B. RAY 7 Re. 19,791

APPARATUS FOR TREATING GASES Original Filed Feb. '7, 1928 '1 ATTORNEYS.

Reissued Dec. 17, 19 35 j 1 Re.

mana'rus FOR TREATING GASES Arthur B. Ray, Bayside, N. Y., assignor to Nany, Inc., a corporation 'tional Carbon Compa New York Original No. 1,820,030, dated All!! 25, 1931,

Serial No. 252,654, February 7,1928.

Application for reissue August 12, 193$,Serlal No.

This invention relates to apparatus -for treatin gases to remove substances therefrom.

The substances to be removed are usually in a gaseous and vapor state, and mixed with the gas 4 Claims. (01. 1am) to be treated. In certaininstances substances may. be removed from gases and recovered because of their valuable nature, such as solvents 1 used in industrial processes which va rize in air; and in other instances substances are removed from gases because they are injurious, odoriterous, and objectionable.

It is particularly desirable to treat air discharged i'rom meatpacking houses, where the waste material from butchered anlmals is treated ior commercial disposal, because the air be- "comes contaminated with objectionable odors.

Much progress has been made in the abatement of the more serious of the. stenches which were emitted. In this manner, one or the principal sources of atmosphere contamination is-removed to a great extent. Some of the fixed gaseous odors, however, still escape from the rendering apparatus into'theisurrounding room. Also, materials of objectionable-odor are still handled in open vessels, as when the oiIal is being macerated,

washed, and charged into the rendering kettles, and when the cooked material is discharged from" the kettles. In this manner, the very large volumesoi air which pass through. the work rooms become contaminated with a relatively small but oil'ensiv'e content of odorii'erous substances.

The use of closed vessels ion the more objectionable stench-producing operations brought about so much improvement that, for a time, there was a tendency to tolerate the less serious stenches still emitted. As sanitary standards have been raised, however, and, as residence districts have drawn closer to existing plants of this character, the necessity for more complete stench abatement has become acute. No means has heretofore been available for this purpose, primarily becauseot the large volumes or air which must be deodorized to render a plantquite unobjectionable.

.Inaccordance with the present invention, the substances are removed from the gases by contacting the latter with granular activated carbon.

,Although I do not wish to be limited thereto, I

preieroo employ the activated carbon materials of the apparatus now tobe described.

described in the U. S. patents to Newcomb K. Chaney No. 1,497,543 and No. 1,497,544, both dated June 10, 1924, and I prefer to use the more active 01' the materials which are there described.

In order toprocess the large volumes of air discharged from ameat packing plant in an apparatus of reasonable size, it is apparent that the air must flow through the deodcrizing apparatus at highveiocity. To force the air at high velocity through beds of granular carbon' requires high pressures and large expediture of power unless the carbon beds are very thin. Thin carbon beds in conjunction with a high air velocity reduce the time of contact 01' the air with the carbon to a very small interval, and it was questionable whether, under economically Ieasible conditions, theair wouldbe sufliciently deodorized. In this connection the low concentration of odoriferous substances in the air entering the purifying apparatus is less significant than the much lower concentration of residual odors which must be attained in the air leaving the apparatus. The concentrations of the substances dealt with are infinitesimal as compared with the concentrations of gasoline, solvent vapors and other materials remaining in gases. after they have been passed through activated carbon 'in prior processes. Even where activated carbon is used in gasmasks, the velocity of the air through the carbon does not approach that necessary in the deodorization of the air from certain sections of meat packing houses. Nevertheless, I have been able to completely deodorize contaminated air from packing houses with-great success by; the use i Reference is to be made to the accompanying drawing in which the single figure is a top view or fa suitable odor-removing apparatus with one end cut awayto show the interior construction.

In this drawing I show-an enclosed vessel, such as a steel tank I, the interior of which is divided into a number of compartments solely by thin vertical layers 2 of activated carbon held in place by any suitable means, such as perforated metal plates. screens, or permeable material in sheetlike form, a face of each bed being exposed to the face oi an adjacent bed. The odor-laden air is passed by a' suitable blower into the air duct 3 and thence through the inlet valves 4 into the interior of the tank. The outlet valves 5 on the opposite side of the tankare so arranged with reference to the inlet valves that all of the air must pass through one or more layers oi activated carbon before it isflnally released tothe atnosphere. Preferably the air passes through but one layer of carbon. Suitable openings 6 are provided on the top and bottom of each of the carbon containers for charging and discharging as desired.

After the carbon has been in service for several months and its deodorizing power has become nearly exhausted, one bed of carbon at a time may be removed from the tank and revivified. During this time the necessary valves leading to and from the proper section of the tankare closed so that no odor-laden air can escape to the atmosphere. After one batch of carbon has been revivified it is again placed in the tank and another batch is removed for reviviflcation. so that the continuous operation of the deodorizingprocess is not hindered. A satisfactory method of revivifying the carbon is to heat it with steam to a temperature of about 300 C. If objectionable materials are driven out of the carbon by the steam, they may be partially condensed and passed'with the water condensate into the sewer or burned.

The particular location of the apparatus in the plant is a matter of convenience, but it is advisable to place it so that the carbon maybe removed when necessary for revivifying with the least possible effort. The discharge holes for the respective beds are so arranged that the carbon may be passed from the vertical containers by gravity directly into the revivifying tank, or onto a suitable conveyor for transferring it to said tank; The apparatus of my invention may of course be used in conjunction with other odor abatement apparatus. For example, in cases where spray chambers are already in use, my apparatus may be used in series with it, and the exhaust air from the spray chamber passed directly' into contact with the carbon where the deodorizing operation is completed. By previously sprayingtthe air with water it appears that ammonia, dust, and possibly some of the volatile odoriferous compounds are removed and the active life of the carbon may thus be considerably prolonged. v

While convenient for some purposes, it is not absolutely necessary to enclose the carbon beds in a metal container, since the main object of the apparatus is to insure passage of the odorladen air through the activated carbon. For instance, the thin vertical beds of cabon may be placed in a brick chamber or an ordinary room and all of the air from the work rooms passed into this chamber or treating room, and thence by suitable dampers through the layers of activated carbon and into the atmosphere.

In determining the amount of activated carbon necessary for completely removing sub stances from a gas, such as in the deodorizing of air, consideration must be given to the volume of gas which it is necessary to treat per minute with a view to the fact that the thickness and area of the carbon bed will determine the power required to force the gas through it. I have found thatwith beds varying from 4 to 8 inches in thickness air may be passed through the beds at a linear velocity of to 100 feet per minute withoutexcessive pressure, and with complete removal of the substances.

In a particular application of the present in- The thickness of the carbon bed which.

the bed for eflfective removal of odors is approximately50 feet per minute. In order to obtain this velocity 9. total carbon bed area of about 600 square feet must be provided. With this total area divided into smaller beds and arranged as 5 already described, the pressure drop through the activated carbon will be approximately equivalent to 3 inches of water.

The ability of activated carbon to adsorb various gases, vapors and other substances is well 10 known, but under the conditions as described I believe that the actual adsorptive power of the carbon is not entirely responsible for the results obtained. It has been observed and is disclosed in the patents and literature that activated car- 15 bon acts as a catalyst in certain reactions, and the ease 'with which many odoriferous compounds may be oxidized has long been recognized.

I therefore believe that the remarkable efilciency of the carbon for the purpose in question, in 2 which the conditions for adsorption are decidedly unfavorable, may be attributed in some cases in part to its catalytic action by which the odoriferous material is actually oxidized and destroyed.

So far as I am aware my apparatus is the first 25 to be designed to meet the combination of requirements which includes the treatment of very large volumes of gas. in inexpensive equipment, a small expenditure of power, and substantially complete removal of a volatile impurity from the 30 gas. For such'purposes a bed of granular carbon of a thickness small in comparison with its area, and sufliciently small to permit the passage of gas .with a velocity of at least 50 feet per minute under a pressure equivalent to 3 inches of, water 35 has unique advantages. a While I have described my invention as being particularly adaptable for use in meat packing houses, it is to be understood that with slight modifications the same apparatus can be used 40 for practically any odor abatement purposes re- Y acter described comprising a tank, the interior 50 of which is separated into a plurality of compartments by means of thin vertical beds of activated carbon arranged in spaced relation therein, inlet valves forthe air to be treated connected with alternate compartments, the air admitted into the alternate compartments dividing and flowing through adjacent beds of carbon, outlet valves connectedwith the remaining compartments, and means provided for individually charging and discharging each of said carbon beds by gravity. 2. In a system for preventing the dissemination of odors in large volumes of air; the combination of a container, a plurality of thin vertical beds of activated carbon arranged in spaced relation I opposite side thereof, said valves being connected to the compartments in a manner whereby the air admitted into alternate compartments divides and flows through adjacent beds of carbon before being released to the atmosphere, and means provided for individually charging and, discharging each carbon bed by gravity.

3. Apparatus for removingan odoriterous substance from air comprising a container, a pinrality of thin vertical beds of activated carbon arranged in spaced relation in said container with a face of each bed exposed to the face of an adjacent bed, means for admitting air containing the substance into alternate spaces formed between said carbon beds, the air admitted into the alternate spaces dividing and flowing through adjacent beds of carbon, means for discharging air from the spaces between those spaces into which air is admitted, and means provided for individually charging and discharging each of said carbon beds by gravity.

4. Apparatus for removing odoriierous subinto the inlet chambers, the air admitted to such inlet chambers dividing and flowing through adjacent carbon beds, means for discharging deodorized air from the outlet chambers, and means provided for individually charging and discharging each of said carbon beds by gravity.

ARTHUR B. RAY.

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