Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Reexamination Certificate
1998-10-20
2001-01-30
Wong, Edna (Department: 1741)
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
C204S158200, C588S253000, C095S273000, C096S016000, C422S024000, C422S121000, C422S124000, C422S186300, C250S437000, C250S438000, C055S307000
Reexamination Certificate
active
06179969
ABSTRACT:
This is a natural stage application of PCT/DK97100182 filed Apr. 23, 1997.
TECHNICAL FIELD
The invention concerns a procedure for removal and/or destructions of organic substances in contaminated air.
BACKGROUND ART
Organic substances in the form of vapours or particles are to a large extend created as undesired secondary products in connection with many production processes within the industry. As examples can be mentioned preparation and use of lacquer and paint, cereal and feedstuff, metal and plastic, tar and asphalt, tanneries, incinerating plants, bio-gas plants, market gardens, agriculture and also large parts of the food industry.
Today severe demands are made to the hygienic and health conditions regarding the work spots/sites as well as to the surrounding milieu. The organic substances mentioned are, however, more or less injurious to health, and furthermore many of them have a foul smell. It will therefore normally not be allowed to leak air contaminated with such organic substances to the surroundings. Purification of the air must take place before that.
This purification normally takes place by filtering he contaminated air in, for example, grease filters and carbon filters. Mechanical filters of this type are, however, rather expensive in use, since they need to be cleaned at short intervals and frequently have to be replaced. Furthermore, the filters cannot fulfill the high hygienic standard, which, for example, is required within the food industry, and to this can be added that filters, which, as an example, are filled with grease, must be considered as extremely flammable.
Furthermore, it is known technology to use ozone for removing especially foul smell from air contaminated with organic substances. The ozone is normally created in an electric arc in the form of the so-called corona-ozone, whereby there as a unfortunate side effect is created NOX, which is damaging the environment and health injuring to human beings.
In other cases different chemicals for decomposing and destroying the organic substances are added to the contaminated air. The chemicals can, however, themselves contribute to contamination of the air, and the same applies to those products which are created by the chemical reactions purifying the air.
SUMMARY OF THE INVENTION
The object of the invention is to provide a procedure of the type mentioned in the opening paragraph, which is capable of eliminating the problems connected to the currently available methods for removal of the organic substances and/or foul smell in the contaminated air.
The novelty and uniqueness of the invention, that the contaminated air is set into a streaming condition; that the created air stream is brought to change direction at least once; that the air stream is cooled off; that secondary air and/or oxygen is added to the air stream; that the air stream is radiated with ultra-violet light; that the air continues to stream for a predetermined interval of time; and that the air stream is let out into the surroundings.
Organic substances in the form of larger particles are initially separated by this method at that stage where the air stream changes direction. Then the air is relieved of particles, which otherwise could restrain the processes in the succeeding process steps.
By cooling off contaminated air, which derives from a hot continuous process, it is attained that water in the form of saturated vapour and organic substance condensate and thereby separate the air released from these vapours more easily can be processed in the succeeding steps of the process.
The oxygen supplied in the form of the oxygen content in a secondary air stream or as pure oxygen serves the sole purpose of securing, that the contaminated air sufficiently is provided with oxygen to create ozone to the necessary extent, when the air is radiated with the ultra-violet light. Since the ozone is created at a low temperature and by means of ultra-violet light, no secondary product, as previously mentioned, in the form of dangerous NOX created by corona effect, will emerge.
Certain organic substances are oxidized by the ozone in a so-called cold combustion and are thereby transformed into carbon dioxide, but many organic molecules can not be oxidized in this way. The ultra-violet light, which radiates the oxygen molecules and thereby creates ozone, will, however, at the same time influence the organic substances with a photo light effect, which splits the organic molecules, which normally would be difficult for the ozone to oxidize into molecules more easy to oxidize by ozone. Thereby is obtained that it is possible to oxidize a larger amount of the content of organic substances in the contaminated air than by means of ozone alone.
The oxidation process does not occur instantaneously, and therefore the air stream is brought to continue as long as the oxidation process of the organic substances takes, before the purified air is being released into e.g. the open air.
When the contaminated air is warmer than the supplied secondary air and/or oxygen, this secondary air advantageously can be used for cooling off the air, before it is radiated by the ultra-violet light.
Furthermore the best effect is obtained by using short wavelength ultra-violet light for the radiation.
The invention also concerns a filter device for removing and/or destroying organic substances in contaminated air, which comprises a house and a least one ventilator for sending the air stream through the house, in which there, in open connection with each other are; a first chamber with an opening, which is connected to a source of contaminated air; a second chamber with a number of metal sheets placed across the main direction of the air current which sheets are to bring the air current to change direction at least one time; a third chamber with a number of perforated tubes, as in secondary air source; a fourth chamber with a number of lamps for radiating the air current with ultra-violet light and; a fifth chamber with a volume allowing the air current, at predetermined interval of time, to stay in the chamber, and which has an opening through which the purified air is released to the surroundings.
By means of this construction the procedure according to the invention can be carried through efficiently and economically. The chambers can, for example, be built vertically on top of each other with the fifth chamber at the top. The air current, which is generated by the ventilator, is then successively passing the various chambers and thereby run through the processes which finally result in purified air being released into open air.
The ventilator can in principle be inserted any place at all in the air current, but it is most expedient to place the ventilator after the fifth chamber and connect its opening with the suction side of the ventilator.
The air passing through the ventilator is thereby purified air only, which prevents the build-up of a coating of organic substances from contaminated air in the ventilator, which would reduce the efficiency of the ventilator.
From the source of contamination the contaminated air streams into the first chamber via its inlet. It is important that the air is distributed equally in the succeeding chambers for the processes to run at their optimum. For this purpose, according to the invention, there can advantageously be placed one or more distribution sheets in the first chamber, preferably somewhere behind the inlet opening of the air.
In the second chamber the air is met by a number of de-cindering sheets forcing the air to sudden change of direction at least one time. Thereby organic particles and water drops are removed from the air.
The sheets are by an expedient embodiment placed in at least two rows across the main direction of the air current in such a way, that the sheets in each row are placed at a mutual interval, and each interval is placed opposite a sheet in the adjoining row.
The lamps for radiating the air, which streams through the fourth chamber, with short wavelength ultra-violet light, can according to the invention be h
Jimco A/S
Pennie & Edmonds LLP
Wong Edna
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