DESC:FIELD
The present disclosure relates to a field of air pollution control. Particularly, the present disclosure relates to a system and a process for the treatment of an off-gas stream.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used, indicates otherwise.
Off gas: The term ‘off-gas’, also known as ‘exhaust gas’ or ‘waste gas’ refer to gases that are produced as a byproduct of an industrial process. Off-gas typically contains a variety of compounds, such as chemical by-products, solvents or malodorous compounds. In industries, these volatile organic compounds (VOCs), carbon monoxide (CO) and hydrocarbons (HC) are emitted by many industrial processes. The off-gases formed at refineries often contain components such as mercaptans, diolefins, olefins, CO2, CO, hydrocarbons, H2S, various organic sulfur species and the like, all of which are harmful to the environment and subject to increasingly stricter regulations.
Odorous compound: The term ‘odorous compound’ or ‘odorant’ or ‘odor-causing compound’ refer to the compounds such as hydrogen sulphide, mercaptans, ammonia, amines, aromatic hydrocarbons and the like causing bad odor.
Sleeve: The term ‘sleeve’ refers to a cylindrical enclosure that can be used to hold a lamp.
Demister pad: The term ‘demister pad’ refers to typically a mesh or fibrous mat made of materials like stainless steel, polypropylene, or other corrosion-resistant materials that is used to remove liquid mist or droplets from a gas stream in industrial processes.
Wire mist eliminator: The term ‘wire mist eliminator’ refers to a type of industrial equipment used to separate and remove mist or fine droplets from gases or air streams, particularly in processes where condensation or aerosol formation occurs. It typically consists of a series of fine wire mesh or fibers arranged in a grid or pack.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
In recent years, due to exponential population growth, the global production of materials has increased significantly. Therefore, along with the production, the by-products such as solid, liquid and gaseous wastes are also generated, leading to a wide array of technical, regulatory and environmental concerns for waste management.
Various processes in an industry lead to the generation of off-gases having an unpleasant odor. The odor is mainly caused by the presence of sulphur compounds, nitrogen compounds, hydrocarbons and the like. In industrial waste treatment, the assessment and selection of waste treatment technologies aim at minimizing waste toxicity and volume. Thus, there should be an optimal balance of treatment efficiency and cost up to final disposal.
The presently available technologies for air emissions/off-gas treatment are bio-filtration, high energy destruction, membrane separation, non-thermal plasma, oxidation, scrubbers, and vapor phase carbon adsorption. Conventionally, scrubbing or incineration techniques are implemented to control or reduce the odor. Another conventional approach is to chemically neutralize the odor-causing compounds present in such gases. Despite the removal of harmful gases using conventional technologies up to a certain limit, the vent gases from these gas treatment units contain odorous components. Furthermore, the smell is reportedly severe during the winter season when the atmospheric temperature is comparatively lower, and also when the air movement is lesser.
A conventional process for reducing odor from refinery off-gas stream comprises contacting the refinery off-gas stream at a predetermined flow rate with an adsorbent, in the presence of steam and UV radiations, at a predetermined temperature and at a predetermined pressure to obtain an off-gas stream having reduced concentration of odorous compounds. However, this process is not capable of removing odorant when at high concentration.
There is, therefore, felt a need for a system and a process for the treatment of an off-gas stream, that overcomes the above-mentioned limitations or at least provides a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide a system for the treatment of an off-gas stream.
Another object of the present disclosure is to provide a system for the treatment of an off-gas stream obtained from various processes.
Still another object of the present disclosure is to provide a system for the treatment of an off-gas stream that is efficient.
Yet another object of the present disclosure is to provide a system for the treatment of an off-gas stream that requires easy and minimal maintenance.
Still another object of the present disclosure is to provide a system for the treatment of an off-gas stream that can be easily integrated with the existing set ups.
Yet another object of the present disclosure is to provide a process for the treatment of an off-gas stream.
Still another object of the present disclosure is to provide an economical process for the treatment of an off-gas stream.
Yet another object of the present disclosure is to provide an environment-friendly process for the treatment of an off-gas stream.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
In an aspect, the present disclosure provides a system for the treatment of an off-gas stream, the system comprises:
at least one duct configured to collect at least one pre-treated off-gas stream from at least one pre-treatment unit;
at least one flow creating unit selected from
a blower fluidly connected with the at least one duct; and
an ejector fluidly connected with an outlet pipe,
configured to create a flow within the system;
at least one filtering unit placed downstream to the at least one duct configured to remove contaminants, oil and water from the pre-treated off-gas stream; and
a plurality of photo-catalytic reactor elements in fluid communication with each other, configured to receive a filtered off-gas stream and further configured to remove the odor from the filtered off-gas stream to obtain a treated gas stream at the outlet pipe.
In accordance with the present disclosure, the at least one photo-catalytic reactor element comprises a cylindrical vessel configured to hold:
a finned cartridge coated with a catalyst selected from group IV B transition metal oxide; and
at least one ultraviolet lamp placed axially within a cylindrical quartz sleeve and supported on an end flange.
In accordance with the present disclosure, the plurality of the photo-catalytic reactor elements is in electronic communication with a power supply unit to supply power to at least one ultra-violet lamp.
In accordance with the present disclosure, the plurality of photo-catalytic reactor elements is in electronic communication with at least one temperature indicator; the temperature indicator is connected to an interlock triggering safe shut down of the system.
In accordance with the present disclosure, the plurality of the photo-catalytic reactor elements is placed in at least one stack.
In accordance with the present disclosure, the pre-treatment unit comprises at least one of the following:
a scrubbing unit configured to receive an off-gas stream and further configured to remove the gases selected from odorants, hydrogen sulfide and carbon dioxide from the off-gas stream; and
an adsorbent canister configured to receive an off-gas stream, optionally placed downstream to the scrubbing unit, and further configured to remove hydrocarbon vapors from the off-gas stream.
In accordance with the present disclosure, the scrubbing unit comprises at least one scrubbing fluid selected from the group consisting of hydrogen peroxide, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), diisopropanolamine (DIPA), methyldiethanolamine (MDEA), and N,N-diethylethanolamine (DEEA).
In accordance with the present disclosure, the adsorbent canister contain a material selected from the group consisting of activated charcoal, zeolite, silica gel, and activated alumina.
In accordance with the present disclosure, the filtering unit contains a filtering medium selected from the group consisting of super-hydrophobic polyurethane foam, cotton, adsorbent, demister pad, and wire mist eliminator.
In accordance with the present disclosure, the at least one filtering unit is fluidly connected with a boot, the boot is configured to collect contaminants, oil and water.
In accordance with the present disclosure, the filtering unit is in electronic communication with at least two pressure transmitters and at least one differential pressure indicator for monitoring a pressure drop across the filtering unit.
In accordance with the present disclosure, the filtering unit is in communication with a level transmitter and a level indicator.
In accordance with the present disclosure,
the blower is configured to provide an additional pressure required to encounter any pressure drop in the duct; and
the ejector is configured to create vacuum to facilitate downstream flow of the treated gas stream.
In accordance with the present disclosure, the treated gas stream is vented out through the outlet pipe at a height in the range of 7 meters to 10 meters.
In accordance with the present disclosure, a source of the off-gas stream is selected from the group consisting of wet air oxidation plant, fish meal processing industry, poultry waste, municipal sewage treatment plant, and an odourous gas containing a compound selected from volatile organic compound, sulfurous compound, nitrous compound and a mixture thereof.
In another aspect, the present disclosure provides a process for the treatment of an off-gas stream, the process comprising the following steps:
passing a pre-treated gas stream through a duct at a first predetermined temperature to obtain a channelized stream;
filtering the channelized stream in at least one filtering unit at a second predetermined temperature to obtain a filtered stream; and
feeding the filtered stream to a plurality of photo-catalytic reactor elements, operating at a third predetermined temperature in the presence of ultraviolet light having a predetermined wavelength followed by treating the filtered stream for a predetermined time period to obtain a treated gas stream at an outlet pipe.
In accordance with the present disclosure, the treated gas stream has odorous compounds at a concentration of less than 1 ppm.
In accordance with the present disclosure, the pre-treated gas stream is obtained by at least one of the following steps:
passing the off-gas stream to at least one scrubbing unit at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(g) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes; and
treating the off-gas stream in an adsorbent canister at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(g) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes;
wherein the adsorbent canister optionally receives a pre-treated gas stream from the scrubbing unit.
In accordance with the present disclosure, the first predetermined temperature is in the range of 22 oC to 200 oC.
In accordance with the present disclosure, the second predetermined temperature is in the range of 22 oC to 200 oC.
In accordance with the present disclosure,
the third predetermined temperature is in the range of 22 oC to 200 oC;
the predetermined wavelength is in the range of 100 nm to 400 nm; and
the predetermined time period is in the range of 5 minutes to 20 minutes.
In accordance with the present disclosure, the off-gas stream has odorous compounds at a concentration in the range of 80 ppm to 300 ppm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
A process and a system for the treatment of an off-gas stream of the present disclosure will now be described with the help of the accompanying drawing, in which:
Fig. 1 illustrates a block diagram of the system for the treatment of an off-gas stream, in accordance with the present disclosure;
Fig. 2 illustrates a process flow diagram of the system for the treatment of an off-gas stream, in accordance with the present disclosure;
Fig. 3a illustrates an elevation view of an arrangement of the photocatalytic reactor elements, in accordance with an embodiment of the present disclosure;
Fig. 3b illustrates a plan view of an arrangement of the photocatalytic reactor elements, in accordance with an embodiment of the present disclosure;
Fig. 4a illustrates an element of the photocatalytic reactor, in accordance with an embodiment of the present disclosure; and
Fig. 4b illustrates a side view of the element of the photocatalytic reactor, in accordance with the present disclosure.
LIST OF REFERENCE NUMERALS
1000 – System for the treatment of an off-gas stream
F1 – Feed 1
F2 – Feed 2
100 – pre-treatment unit
10 – scrubbing unit
20 – adsorbent canister
30 – treated stream
200 – duct
300 – flow creating unit
302 – blower
304 – ejector
400 – filtering unit
402, 404 – pressure transmitters
406 – differential pressure indicator
408 – boot
410 - level transmitter
412 - level indicator
500 – photo-catalytic reactor elements
502 – cylindrical vessel
504 - catalyst coated finned cartridge
506 – ultra-violet lamp
508 – cylindrical quartz sleeve
510 – end flange
512 – Nipple
514 – “O” ring
516 – Quartz
518 – cable
520 – compression nut set
522 – gland
524 – cable (Teflon and silicon)
526 – lamp holder
550 – temperature indicator
552 – pressure indicator
700 – power supply unit
DETAILED DESCRIPTION
The present disclosure relates to a system and a process for the treatment of an off-gas stream.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawings.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, specific processes specific apparatus structures, and unique techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
When an element is referred to as being “mounted on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
Terms such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
In recent years, due to exponential population growth, the global production of materials has increased significantly, leading to a wide array of technical, regulatory and environmental considerations for waste management.
The conventional deodoring units such as H2S scrubber and reaction chamber used in the Wet Air Oxidation (WAO) plant are known to cause odor not only in the vicinity of Wet Air Oxidation (WAO) unit but also in the neighborhood. The smell becomes severe during the winter season when the atmospheric temperature is low and the air movement is less.
In an aspect, the present disclosure provides a system and a process for the treatment of an off-gas stream. The system and the process have been described with the help of drawings as disclosed in Fig. 1 to Fig. 4.
In accordance with the present disclosure, the off-gas can include the odor-causing compounds selected from hydrogen sulphide, mercaptans, ammonia, amines, and aromatic hydrocarbons.
As shown in Fig. 1 and Fig. 2, the system (1000) for the treatment of an off-gas stream comprises at least one pre-treatment unit (100), at least one duct (200), at least one flow creating unit (300 – not shown in figure), at least one filtering unit (400), and a plurality of photo-catalytic reactor elements (500).
In accordance with the present disclosure, a source of the off-gas stream is selected from the group consisting of wet air oxidation plant, fish meal processing industry, poultry waste, municipal sewage treatment plant and an odourous gas containing a compound selected from volatile organic compound, sulfurous compound, nitrous compound and a mixture thereof. In an embodiment, a source of the off-gas stream is a neutralization tank (F1) and reaction chamber (F2) of a wet air oxidation (WAO) plant.
In accordance with the present disclosure, the pre-treatment unit (100) comprises at least one of the following: a scrubbing unit (10) and an adsorbent canister (20). The scrubbing unit (10) is configured to receive an off-gas stream and further configured to remove the gases selected from odorants, hydrogen sulfide and carbon dioxide from the off-gas stream. The adsorbent canister (20) is configured to receive an off-gas stream and further configured to remove hydrocarbon vapours from the off-gas stream.
In accordance with the present disclosure, the scrubbing unit (10) comprises at least one scrubbing fluid selected from the group consisting of hydrogen peroxide, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), diisopropanolamine (DIPA), methyldiethanolamine (MDEA), and N,N-diethylethanolamine (DEEA). In an exemplary embodiment, the scrubbing unit (10) comprises hydrogen peroxide as a scrubbing fluid.
In accordance with the present disclosure, the adsorbent canister (20) contain a material selected from the group consisting of activated charcoal, zeolite, silica gel, and activated alumina. In an exemplary embodiment, the adsorbent canister (20) contain activated charcoal.
As shown in Fig. 2, the off-gas from a neutralization tank (F1) of the WAO plant contains hydrogen sulphide and other odorants. In an embodiment, these odorants from the neutralization tank off-gas are treated by using a scrubbing unit (10).
In an embodiment, the pre-treatment unit (100) comprises at least one adsorbent canister (20), optionally placed downstream to the scrubbing unit (10), configured to remove odorants, hydrogen sulfide, carbon dioxide and hydrocarbon vapors from the off-gas stream.
In an embodiment, as shown in Fig. 2, the off-gas from the reaction chamber (F2) of the WAO plant is treated in the at least one adsorbent canister (20), after treating in the scrubbing unit (10).
Although the pre-treated off-gas stream brought down the hydrogen sulphide concentration to a safe limit, this stream still contains odorous components.
In accordance with the present disclosure, at least one duct (200) is configured to collect at least one pre-treated off-gas stream from at least one pre-treatment unit (100).
In accordance with the present disclosure, the flow creating unit (300) is selected from a blower (302) and an ejector (304), which are configured to create a flow within the system.
In accordance with the present disclosure, the blower (302) in fluid communication with the at least one duct (200) configured to provide an additional pressure required to encounter any pressure drop in the duct (200).
In accordance with the present disclosure, the ejector (304) is fluidly connected with an outlet pipe (30), configured to create vacuum to facilitate downstream flow of the treated gas stream at an outlet pipe (30). The flow across the reactor can be either forced through a blower upstream of the photo-catalytic reactor or through an ejector/vacuum pump placed downstream of the photo-catalytic reactor. In case of blowers, the pressure is positive and in case of the ejector, the pressure is negative in the latter case.
In accordance with the present disclosure, at least one filtering unit (400) is placed downstream to the at least one duct (200). The at least one filtering unit (400) is configured to remove contaminants, oil and water from the pre-treated off-gas stream.
Generally, in the WAO equipment, in order to aspirate air and prevent vacuum build up, the suction from the vent is open to the atmosphere. The vents and the collection section of the WAO equipment are covered with a hood to prevent rain water entering into the system. In an embodiment, the blower (300) which is downstream to the vent of the WAO equipment is configured to provide an additional pressure head required to encounter any pressure drop in the duct (200). In another embodiment, any water ingression into the system as well as the oily contaminants present in the vent gas from WAO equipment are removed from the off gas stream by passing the off gas through the filter.
In accordance with the present disclosure, the filtering unit (400) contains a filtering medium selected from the group consisting of super-hydrophobic polyurethane foam, cotton, adsorbent, demister pad and wire mist eliminator. In an exemplary embodiment, the filtering medium is super-hydrophobic polyurethane foam.
The filtering medium prevents any amount of water and hydrocarbon from being carried downstream. The superhydrophobic polyurethane foam and cotton repels water from passing through which in turn tends to coalesce and collect in downstream the boot (408). The adsorbent also adsorbs the hydrocarbon oils present in the off gas stream.
In accordance with the present disclosure, the at least one filtering unit (400) is fluidly connected with a boot (408), wherein the boot (408) is configured to collect contaminants, oil and water.
In an embodiment, the filtering unit (400) is place at the lowest point in the system. Free moisture blocks the catalyst surface and removes the catalyst coating over the surface. Hence, free moisture is removed in the filtering unit. However, if there is any saturated water condensation in the photocatalytic reactor, placing the filtering unit at the lowest point ensures that the condensed water flows back and free drains to the filtering unit.
In accordance with the present disclosure, the filtering unit (400) is in electronic communication with at least two pressure transmitter (402, 404) and at least one differential pressure indicator (406) for monitoring any pressure drop across the filtering unit (400).
In an embodiment, the pressure transmitter (402) is placed upstream to the filtering unit (400), and the pressure transmitter (404) is placed downstream to the filtering unit (400).
In accordance with the present disclosure, the filtering unit (400) is in electronic communication with a level transmitter (410) and a level indicator (412) to ensure the proper draining of the filtered water.
In an embodiment, the level transmitter (410) also has an interlock that will trip the system in case the water level reaches a point nearing a break through condition.
The filtering unit (400) eliminates the free moisture present in the off-gas stream. The presence of free moisture in the feed stream of the photocatalytic reactor affect the treatment efficiency.
In accordance with the present disclosure, a plurality of photo-catalytic reactor elements (500) are in fluid communication with each other, configured to receive a filtered off-gas stream. The plurality of the photo-catalytic reactor elements (500) are further configured to remove the odor from the filtered off-gas stream to obtain a treated gas stream at the outlet pipe (30).
In accordance with the present disclosure, the plurality of the photo-catalytic reactor elements (500) are placed in at least one stack and fluidly connected to each other in series, providing a unique geometric structure and design of the photo-catalytic reactor elements. In an exemplary embodiment, total eight photo-catalytic reactor elements (500) are arrange in two stacks.
In an embodiment, the photo-catalytic reactor elements (500) has a count in the range of 20 to 30. In another embodiment, the photo-catalytic reactor element (500) has a count of 24.
In an embodiment, the photocatalytic reactor elements (500) comprising twenty-four photo-catalytic reactor elements arranged in series as shown in Fig. 3a and Fig. 3b. Fig. 3a illustrates an elevation view of the photocatalytic reactor elements (500) in accordance with an embodiment of the present disclosure. Fig. 3b illustrates a plan view of the photocatalytic reactor elements (500) in accordance with an embodiment of the present disclosure. The photocatalytic reactor elements (500) are stacked in layers wherein the last element in the lower layer is connected to the first element in the upper layer.
In accordance with the present disclosure, as shown in Fig. 4a and Fig. 4b, the at least one photocatalytic reactor element (500) comprises cylindrical vessel (502) configured to hold: a finned cartridge (502) coated with a catalyst and at least one ultra-violet lamp (506).
In accordance with the present disclosure, the catalyst is selected from group IV B transition metal oxide. In an embodiment, the catalyst is selected from the group consisting of titanium oxide (TiO2), zirconium oxide (ZrO2), and hafnium oxide (HfO2).
In accordance with an embodiment, the system of the present disclosure can be used for any inlet concentration of an off-gas stream, and the size of the photocatalytic reactor – mainly surface area of catalyst, and radiation intensity can be accordingly calculated. For a given odorant concentration, flow rate can be either be scaled up or scaled down to any quantity, corresponding to the surface area of catalyst and radiation intensity.
In accordance with the present disclosure, the surface area is computed (scaled up or scaled down) for different odour composition, odorous off-gas stream flow rate and radiation flux.
In accordance with an embodiment of the present disclosure, the photo-catalytic reactor has the catalyst coating with a surface area in the range of 3 m2 to 4 m2 for radiation intensity of 150 W/m2 and flow rate of 16 Nm3/h with 300 ppm odorants. In accordance with the present disclosure, the at least one ultraviolet lamp (506) is placed axially within a cylindrical quartz sleeve (508) and supported on an end flange (510).
The ultraviolet lamp (506) and the finned cartridge (504) are further assembled with a nipple (512), an “O” ring (514), a quartz (516), cable (518), compression nut set (520), gland (522), Teflon and silicon cables (524), and lamp holder (526).
In accordance with the present disclosure, the plurality of the photo-catalytic reactor elements (500) are in electronic communication with a power supply unit (700) to supply power to at least one ultra-violet lamp (506).
In accordance with the present disclosure, the plurality of photocatalytic reactor elements (500) are in electronic communication with at least one temperature indicator (550). The temperature indicator (550) is connected to an interlock triggering safe shut down of the system. The nitrogen gas is purged to cut off oxygen in case of emergency such as electrical fire, fire, explosion and other causes. The system of the present disclosure is equipped with instrumentation and control for auto shut down in case of any undesired condition in the reactor.
In accordance with the present disclosure, each photocatalytic reactor (500) has two ultraviolet lamps (506) of power in the range of 12 W to 150 W depending in the odor concentration and reduction efficiency. In an embodiment, UV-C light is used to efficiently remove the odor from the off-gas stream.
The photocatalytic reactor elements (500) are placed in a compact and space efficient manner.
In accordance with present disclosure, an element of the photo-catalyst reactor can be isolated and opened for inspection or catalyst coating.
In accordance with the present disclosure, the catalyst activity decreases step by step while the operation duration increases. The odorant conversion across the reactor elements (500) is monitored continuously, once the conversion falls below the acceptable odor threshold value, the catalyst is recoated.
In accordance with the present disclosure, the catalyst is coated on the finned cartridge over the internal surface of the photocatalytic reactor at a thickness in the range of 0.5 mm to 1.5 mm. In an exemplary embodiment, the catalyst is coated on the finned cartridge at a thickness of 1 mm.
The odorous components present in the filtered off-gas stream are removed in by a UV photocatalytic reaction with metal-oxide catalyst.
The system of the present disclosure requires minimal modifications to integrate with the existing systems such as WAO plant and the like.
In an embodiment, a hydrocarbon analyzer is placed in vicinity to the reaction chamber (F2) vent.
In another embodiment, an additional pressure transmitter (552) is provided downstream to the photocatalytic reactor elements (500). The pressure transmitter (552) is used for safe operations. If there is any choking or combustion or explosion inside the system, the pressure transmitter will indicate the rise in the pressure.
In an embodiment, the system for the treatment of an off-gas stream of the present disclosure is designed to remove odorants at 100 ppm vol from ~16 Nm3/h vent gas from the WAO reaction chamber and H2S scrubber with an on stream factor of 8000 h/year.
In an embodiment, the hydrogen sulphide content is monitored through a detector placed near the photocatalytic reactor outlet pipe (30).
In accordance with the present disclosure, the treated gas stream is vented out through the outlet pipe (30) at a height in the range of 7 meters to 10 meters. In an exemplary embodiment, the treated gas stream is vented out through the outlet pipe (30) at a height of 8 meters.
The system of the present disclosure is capable to remove the odorant having high concentration in the range of 80 ppm vol to 300 ppm vol, and reduce it to a concentration of less than 1 ppm vol. 1 ppm vol of the odorant disperse completely within 500 m radius beyond which the concentration is below the odor threshold limit.
The reaction kinetics depends on surface area of the catalyst, UV-C radiation intensity and residence time. The reaction rate follows Langmuir-Hinshelwood kinetics:
r_A= (-k_(c .) k_(LH.) c_A)/(?1+k?_(LH.) c_A )
Thus, at steady state flow rate of the odorous gas, integration from the mole balance and Plug Flow Reactor design equation (Chemical Reaction Engineering principle) yields surface area necessary for a desired conversion as a logarithmic (or exponential) relation to ratio of inlet and outlet odorous components concentration as below:
S.A.=?_0 {1/(k_c.k_LH ) ln(C_(A in)/C_(A out) )+ (C_(A out)-C_(A in) )/k_c }
Each element of the reactor is designed to maximize both the surface area and UV-C illumination over it. The number of elements are arrived based on the surface area (S.A.) calculated based on the equation above.
In a nutshell, there is a direct/exponential relation between the element number and the percentage of odor removal.
In an embodiment, the system for the treatment of an off-gas stream is adapted for remote monitoring and controlling.
In another aspect, the present disclosure provides a process for the treatment of an off-gas stream. The process comprising the following steps:
A pre-treated gas stream through a duct (200) at a first predetermined temperature to obtain a channelized stream.
In accordance with the present disclosure, the pre-treated gas stream is obtained by at least one of the following steps:
The off-gas stream is passed to at least one scrubbing unit (10) at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(g) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes to obtain the pre-treated gas stream.
In an exemplary embodiment, the off-gas stream is passed to at least one scrubbing unit (10) at 50 oC and 7.5 millibar(g) for 15 minutes to obtain the pre-treated gas stream.
The off-gas stream is treated in an adsorbent canister (20) at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(g) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes to obtain the pre-treated gas stream.
In an exemplary embodiment, the off-gas stream is treated in an adsorbent canister (20) 50oC at 7.5 millibar(g) to 1 bar(g) for 15 minutes to obtain the pre-treated gas stream.
In an embodiment, the adsorbent canister (20) optionally receives a pre-treated gas stream from the scrubbing unit (10).
In accordance with the present disclosure, the first predetermined temperature is in the range of 22 oC to 200 oC. In an exemplary embodiment, the first predetermined temperature is 35 oC. As the off-gas stream is not cooled during the process, the first predetermined temperature can vary based on the feed stream temperature.
In accordance with an embodiment of the present disclosure, the pre-treated gas stream is passed through the duct at a flow rate is in the range of 15 kg/hr to 30 kg/hr. In an exemplary embodiment, the pre-treated gas stream is passed through the duct at a flow rate is 21 kg/hr.
The channelized stream is filtered in at least one filtering unit (400) at a second predetermined temperature to obtain a filtered stream.
In accordance with the present disclosure, the second predetermined temperature is in the range of 22 oC to 200 oC. In an exemplary embodiment, the second predetermined temperature is 35 oC. As the off-gas stream is not cooled during the process, the second predetermined temperature can vary based on the feed stream temperature.
In accordance with the present disclosure, the filtered stream is fed to a plurality of photo-catalytic reactor elements (500), operating at a third predetermined temperature in the presence of ultraviolet light having a predetermined wavelength followed by treating the filtered stream for a predetermined time period to obtain a treated gas stream at an outlet pipe (30).
In accordance with the present disclosure, the third predetermined temperature is in the range of 22 oC to 200 oC. In an exemplary embodiment, the third predetermined temperature is 35 oC. As the off-gas stream is not cooled during the process, the third predetermined temperature can vary based on the feed stream temperature.
In accordance with the present disclosure, the predetermined wavelength is in the range of 100 nm to 400 nm. In an exemplary embodiment, the predetermined wavelength is in the range of 100 nm to 280 nm, using the UV-C.
In accordance with the present disclosure, the predetermined time period is in the range of 5 minutes to 20 minutes. In an exemplary embodiment, the predetermined time period is 10 minutes.
In accordance with the present disclosure, the off-gas stream has odorous compounds at a concentration in the range of 80 ppm to 300 ppm. In an exemplary embodiment, the off-gas stream has odorous compounds at a concentration of 100 ppm.
In accordance with the present disclosure, the treated stream (30) has odorous compounds at a concentration of less than 1 ppm. The treated stream (30) can be vented into the atmosphere. In an embodiment, a vent from the photocatalytic reactor elements (500) to the atmosphere is at a minimum height of 8 meters. In another embodiment, a hydrogen sulphide analyzer is placed in vicinity to the vent from the photocatalytic reactor elements (500). The minimum height of the vent at the outlet pipe (30) is arrived based on height required to disburse and dilute the 1 ppm odorant to less than odor threshold limit detected by humans of a specific odorous compound at ground level within a predetermined distance from the photo-catalytic reactor.
The process of the present disclosure is simple, cost-effective, and environment friendly.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the experiments should not be construed as limiting the scope of embodiments herein.
EXPERIMENTAL DETAILS
Example 1: Process for the treatment an off-gas stream in accordance with the present disclosure
Pre-treatment of an off-gas stream were performed by following options:
Option 1: Pre-treatment of an off-gas stream in a scrubbing unit
An off-gas stream from a neutralizer tank (F1) of WAO plant was treated in at least one scrubbing unit (10) at 50 oC and at 7.5 millibar(g) for 15 minutes to obtain a pre-treated gas stream.
Option 2: Pre-treatment of an off-gas stream in an adsorbent canister
An off-gas stream was treated in an adsorbent canister (20) at 50 oC and 7.5 millibar(g) for 15 minutes to obtain a pre-treated gas stream.
Option 3: Pre-treatment of an off-gas stream in a scrubbing unit and an adsorbent canister
An off-gas stream from a neutralizer tank (F1) of WAO plant was treated in at least one scrubbing unit (10) at 50 oC and at 7.5 millibar(g) for 15 minutes to obtain a first pre-treated gas stream. The first pre-treated gas stream was further treated in an adsorbent canister (20) at 50oC and 7.5 millibar(g) for 15 minutes to obtain a pre-treated gas stream.
The pre-treated gas stream so obtained was further treated in two mode operations: (i) a blower mode and (ii) an ejector mode to maintain a constant flow rate throughout the system.
The pre-treated gas stream from the scrubbing unit and the adsorbent canister were combined and passed through a duct (200) at 35 oC (ambient temperature). The blower mode and the ejector mode was operated at the ambient temperature (35 oC) throughout the system.
In the blower mode, to maintain the flow rate of 21 kg/hour in the system the pressure at blower suction was -2.5 millibar(g) and the pressure at the blower discharge was 7900 mmWCg pressure (0.77 bar(g)). The pressurized stream then passes through a filtering unit with a pressure at filter suction of 0.77 bar(g) and the pressure at filter discharge was 0.088 bar(g). The filtered stream then passed through the photocatalytic reactor chamber at a discharge pressure of 0.05 bar(g). The so obtained treated stream has an odorant content of < 1 ppm vol.
The blower used had a capacity Q=16.2 m3/hr and power P=572 W. The filter has diameter d=0.21 m, and length l=0.67 m, the photocatalytic reactors utilize power P=48.20±0.10 W, and had surface area of 80.8 m3.
In the ejector mode, the blower mode was not operated. The initial pressure at the filter suction was -0.005 bar(g), and the pressure at the filter discharge was maintained at -0.0150 bar(g). The filtered stream then passed through the photocatalytic reactor chamber at a discharge pressure of -0.02 bar(g). The so obtained treated stream has a concentration of odorous compounds of <1 ppm vol.
The details for the blower mode and ejector mode are given in Table 1.
Table 1
Parameters Units Blower mode Ejector mode
Flow Nm3/h 16.20 16.20
Temperature at Neutralisation tank/ H2S scrubber °C 40 to 60 40 to 60
Pressure at Neutralisation tank/ H2S scrubber Millibar(g) 5 to 10 5 to 10
Temperature at blower suction °C 30 to 50 Not applicable
Pressure at blower suction Millibar(g) -2.5 Not applicable
Odorant at blower/filter suction ppm vol 100 100
Temperature at blower discharge °C 35 to 100* -
Pressure at blower discharge Bar(g) 0.77 Not applicable
Pressure at Filter suction Bar(g) 0.77 -0.005
Temperature at Filter suction °C 30 to 50* 30 to 50*
Temperature at Filter discharge °C 30 to 50* 30 to 50*
Pressure at Filter discharge Bar(g) 0.088 -0.0150
Pressure at photocatalytic reactors discharge Bar(g) 0.05 -0.02
Temperature at photocatalytic reactors discharge (4) °C 30 to 50* 35 to 50*
Odorant at photocatalytic reactor ppm vol <1 <1
*Temperatures at the blower and the photocatalytic reactor were less than neutralization tank and H2S scrubber because atmospheric air was also sucked along with their odorous vent by blowers
Mass flow rate at the blower suction, blower discharge, filter discharge and the photocatalytic discharge was maintained at 21 kg/hr in the blower mode and ejector mode. Air flow rate at the blower suction, blower discharge, filter discharge and the photocatalytic discharge was maintained at 16.2 Nm3/hr in the blower mode and ejector mode.
Vent to atmosphere was kept at a minimum height of 8 meters, filter was placed at the lowest point, hydrocarbon (HC) analyzer was placed close to the photocatalytic reactor chamber vent. Each stack of the photocatalytic reactor S1, S2, S3 had 4x2 reactor elements. Hydrogen sulphide (H2S) analyzer was placed close to photocatalytic reactor chamber vent.
Efficiency of the system in accordance with the present disclosure
Multiple trials were performed for the treatment of an off-gas stream by using the system of the present disclosure. The results for the efficiency of the system are as provided in Table 2.
Table 2
Sr.
No. Odorants H2S COS MeSH EtSH DMS CS2 2-PropSH 1-PropSH Thio-phene Total sulfur components
1 System inlet 1.80 3.25 6.66 4.70 0.45 0.45 0.18 0.00 0 17.49
System oulet 1.30 1.20 0.85 0.70 0.25 0.05 0.00 0.06 0.00 4.41
% Reduction 74.79
2 System inlet 0.04 1.30 2.55 3.89 2.92 0.11 0.15 0.25 0.02 11.23
System oulet 0.03 0.42 0.33 0.45 0.62 0.03 0.03 0.06 0.00 1.97
% Reduction 82.46
3 System inlet 0.00 1.45 1.22 1.35 1.64 0.05 0.05 0.04 0 5.80
System oulet 0.00 0.25 0.18 0.20 0.16 0.01 0.01 0.00 0.00 0.81
% Reduction 86.03
4 System inlet 0.03 2.25 2.89 4.56 3.66 0.15 0.14 0.22 0.02 13.92
System oulet 0.02 0.59 0.46 0.52 0.66 0.03 0.03 0.06 0.00 2.37
% Reduction 82.97
5 System inlet 0.01 1.42 1.58 2.56 2.22 0.07 0.06 0.09 0 8.01
System oulet 0.00 0.20 0.32 0.46 0.25 0.02 0.02 0.03 0.00 1.30
% Reduction 83.77
6 System inlet 0.02 1.95 3.96 4.88 0.02 0.08 0.25 0.09 0 11.25
System oulet 0.01 0.57 0.52 0.75 0.00 0.03 0.01 0.00 0.00 1.89
% Reduction 83.20
7 System inlet 0.82 1.85 3.26 3.33 0.02 0.08 0.15 0.02 0 9.53
System oulet 0.43 0.92 0.04 0.04 0.00 0.01 0.00 0.00 0.00 1.44
% Reduction 84.89
8 System inlet 0.02 2.58 3.66 4.33 0.62 0.42 0.87 0.09 0.00 12.59
System oulet 0.00 0.64 0.35 0.25 0.15 0.15 0.05 0.02 0.00 1.61
% Reduction 87.21
9 System inlet 0.09 3.99 4.55 4.95 0.44 0.33 0.66 0.12 0.00 15.13
System oulet 0.03 0.42 0.32 0.33 0.25 0.19 0.09 0.05 0.00 1.68
% Reduction 88.90
10 System inlet 0.04 2.45 3.41 4.12 0.45 0.38 1.21 0.33 0.00 12.39
System oulet 0.02 0.51 0.22 0.15 0.19 0.22 0.15 0.06 0.00 1.52
% Reduction 87.73
11 System inlet 0.03 3.98 5.21 6.44 0.59 0.55 1.85 0.54 0.00 19.19
System oulet 0.00 0.78 0.33 0.21 0.28 0.35 0.22 0.11 0.00 2.28
% Reduction 88.15
12 System inlet 0.02 3.11 4.15 4.22 0.45 0.42 0.65 0.18 0.00 13.20
System oulet 0.00 0.52 0.22 0.18 0.25 0.26 0.19 0.05 0.00 1.67
% Reduction 87.35
13 System inlet 0.10 3.36 2.18 1.98 0.11 0.08 0.12 0.08 0.00 8.01
System oulet 0.01 0.33 0.11 0.10 0.00 0.03 0.00 0.00 0.00 0.58
% Reduction 92.76
14 System inlet 0.05 3.88 3.48 2.88 0.08 0.15 0.19 0.11 0.02 10.84
System oulet 0.02 0.42 0.28 0.18 0.02 0.05 0.11 0.08 0.00 1.16
% Reduction 89.30
15 System inlet 0.03 3.22 3.28 2.44 0.07 0.12 0.15 0.08 0.02 9.41
System oulet 0.01 0.35 0.26 0.21 0.04 0.07 0.07 0.05 0.00 1.06
% Reduction 88.74
16 System inlet 0.01 3.66 4.98 5.55 0.42 0.36 1.41 0.25 0.00 16.64
System oulet 0.00 0.64 0.32 0.25 0.27 0.32 0.23 0.13 0.00 2.16
% Reduction 87.02
17 System inlet 0.05 1.96 3.56 3.33 0.11 0.28 0.15 0.02 0.00 9.46
System oulet 0.02 0.59 0.33 0.32 0.05 0.12 0.01 0.00 0.00 1.44
% Reduction 84.78
18 System inlet 0.05 1.55 3.36 3.02 0.15 0.25 0.19 0.03 0.00 8.60
System oulet 0.02 0.45 0.48 0.28 0.08 0.09 0.03 0.00 0.00 1.43
% Reduction 83.37

Effluent summary:
Oily water
The oily water was collected from moisture filter. Normally, there was no free water from the off gas. However, atmospheric air can possibly contain traces of water due to rain or other weather conditions. Oily water is routed to closed drain in WAO unit.
Solid waste
Catalyst coated tubes at the end of life
The catalyst activity decreased step by step with the increase in operation duration. The odorant conversion across the unit was monitored continuously, once the conversion falls below the acceptable odor threshold value, the catalyst was recoated.
Filtering disposal
The feed filters were equipped with disposal Superhydrophobic PU Foam and cotton, once plugged, the cotton was disposed to hazardous waste bin of WAO.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a system for the treatment an off-gas stream that:
is easy and safe to operate;
has a compact design;
is simple and cost-effective; and
requires minimal modifications to integrate in various existing set ups such as WAO plant and the like;
and
a process for the treatment of an off-gas stream that:
is simple to perform;
is cost-effective;
is environment-friendly; and
reduces the odorous components in the gases to less than 1 ppm vol.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Any discussion of materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1) A system (1000) for the treatment of an off-gas stream, said system comprises:
• at least one duct (200) configured to collect at least one pre-treated off-gas stream from at least one pre-treatment unit (100);
• at least one flow creating unit (300) selected from
(i) a blower (302) fluidly connected with said at least one duct (200); and
(ii) an ejector (304) fluidly connected with an outlet pipe (30),
configured to create a flow within said system (1000);
• at least one filtering unit (400) placed downstream to said at least one duct (200) configured to remove contaminants, oil and water from said pre-treated off-gas stream; and
• a plurality of photo-catalytic reactor elements (500) in fluid communication with each other, configured to receive a filtered off-gas stream and further configured to remove the odor from said filtered off-gas stream to obtain a treated gas stream at said outlet pipe (30).
2) The system as claimed in claim 1, wherein said at least one photo-catalytic reactor element (500) comprises a cylindrical vessel (502) configured to hold:
• a finned cartridge (504) coated with a catalyst selected from group IV B transition metal oxide; and
• at least one ultraviolet lamp (506) placed axially within a cylindrical quartz sleeve (508) and supported on an end flange (510).
3) The system as claimed in claim 1, wherein said plurality of the photo-catalytic reactor elements (500) is in electronic communication with a power supply unit (700) to supply power to at least one ultra-violet lamp (506).
4) The system as claimed in claim 1, wherein said plurality of photo-catalytic reactor elements (500) is in electronic communication with at least one temperature indicator (550); said temperature indicator (550) is connected to an interlock triggering safe shut down of the system.
5) The system as claimed in claim 1, wherein said plurality of the photo-catalytic reactor elements (500) is placed in at least one stack.
6) The system as claimed in claim 1, wherein said pre-treatment unit (100) comprises at least one of the following:
(i) a scrubbing unit (10) configured to receive an off-gas stream and further configured to remove the gases selected from odorants, hydrogen sulfide and carbon dioxide from said off-gas stream; and
(ii) an adsorbent canister (20) configured to receive an off-gas stream, optionally placed downstream to said scrubbing unit (10), and further configured to remove hydrocarbon vapors from said off-gas stream.
7) The system as claimed in claim 6, wherein
• said scrubbing unit (10) comprises at least one scrubbing fluid selected from the group consisting of hydrogen peroxide, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), diisopropanolamine (DIPA), methyldiethanolamine (MDEA), and N, N-diethylethanolamine (DEEA); and
• said adsorbent canister (20) contain a material selected from the group consisting of activated charcoal, zeolite, silica gel, and activated alumina.
8) The system as claimed in claim 1, wherein said filtering unit (400) contains a filtering medium selected from the group consisting of super-hydrophobic polyurethane foam, cotton, adsorbent, demister pad, and wire mist eliminator.
9) The system as claimed in claim 1, wherein said at least one filtering unit (400) is fluidly connected with a boot (408), said boot (408) is configured to collect contaminants, oil and water.
10) The system as claimed in claim 1, wherein said filtering unit (400) is in electronic communication with at least two pressure transmitters (402, 404) and at least one differential pressure indicator (406) for monitoring a pressure drop across said filtering unit (400).
11) The system as claimed in claim 1, wherein said filtering unit (400) is in communication with a level transmitter (410) and a level indicator (412).
12) The system as claimed in claim 1, wherein
• said blower (302) is configured to provide an additional pressure required to encounter any pressure drop in said duct (200); and
• said ejector (304) is configured to create vacuum to facilitate downstream flow of said treated gas stream.
13) The system as claimed in claim 1, wherein said treated gas stream is vented out through said outlet pipe (30) at a height in the range of 7 meters to 10 meters.
14) The system as claimed in claim 1, wherein a source of said off-gas stream is selected from the group consisting of wet air oxidation plant, fish meal processing industry, poultry waste, municipal sewage treatment plant and an odorous gas containing a compound selected from volatile organic compound, sulfurous compound, nitrous compound and a mixture thereof.
15) A process for the treatment of an off-gas stream, said process comprising the following steps:
i) passing a pre-treated gas stream through a duct (200) at a first predetermined temperature to obtain a channelized stream;
ii) filtering said channelized stream in at least one filtering unit (400) at a second predetermined temperature to obtain a filtered stream; and
iii) feeding said filtered stream to a plurality of photo-catalytic reactor elements (500), operating at a third predetermined temperature in the presence of ultraviolet light having a predetermined wavelength followed by treating said filtered stream for a predetermined time period to obtain a treated gas stream at an outlet pipe (30).
16) The process as claimed in claim 15, wherein said treated gas stream has odorous compounds at a concentration of less than 1 ppm.
17) The process as claimed in claim 15, wherein said pre-treated gas stream is obtained by at least one of the following steps:
• passing said off-gas stream to at least one scrubbing unit (10) at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(g) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes; and
• treating said off-gas stream in an adsorbent canister (20) at a temperature in the range of 22 oC to 100 oC at a pressure in the range of 1 millibar(b) to 1 bar(g) for a time period in the range of 1 minute to 30 minutes;
wherein said adsorbent canister (20) optionally receives a pre-treated gas stream from said scrubbing unit (10).
18) The process as claimed in claim 15, wherein said first predetermined temperature is in the range of 22 oC to 200 oC.
19) The process as claimed in claim 15, wherein said second predetermined temperature is in the range of 22 oC to 200 oC.
20) The process as claimed in claim 15, wherein
• said third predetermined temperature is in the range of 22 oC to 200 oC;
• said predetermined wavelength is in the range of 100 nm to 400 nm; and
• said predetermined time period is in the range of 5 minutes to 20 minutes.
21) The process as claimed in claim 15, wherein said off-gas stream has odorous compounds at a concentration in the range of 80 ppm to 300 ppm.

Dated this 22nd Day of March 2025

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI