WO2014073004A2

WO2014073004A2 - Carbondioxide removal system

Info

Publication number: WO2014073004A2
Application number: PCT/IN2013/000689
Authority: WO
Inventors: Manish MONGA
Original assignee: Airef Engineers Pvt. Ltd.
Priority date: 2012-11-08
Filing date: 2013-11-08
Publication date: 2014-05-15
Also published as: WO2014073004A4; WO2014073004A3

Abstract

The present invention relates to a system and method for removing carbon dioxide particles in a closed environment of high carbon dioxide concentration. The invention describes an improved method for removing carbon dioxide from a re-circulating gas stream by means of a carbon dioxide adsorbent resin in a closed habitat environment.

Description

"CARBONDIOXIDE REMOVAL SYSTEM

FIELD OF THE INVENTION

The present invention relates to a method and system for removing carbon dioxide (C0₂) particles in a closed environment of high carbon dioxide concentration. More particularly/ this invention relates to an improved method for removing carbon dioxide from a re-circulating gas stream by means of a carbon dioxide adsorbent resin, wherein the said gas stream is derived from a breathable atmosphere in a closed habitat environment.

BACKGROUND OF THE INVENTION

It is well known that indoor level of carbon dioxide concentration is usually higher due to the carbon dioxide exhaled by the occupants. An increase in carbon dioxide concentration may cause harm to human metabolism, especially when rooms are poorly ventilated. The situation can be more worst if large number of occupants is present in a closed environment. Thus a significant amount of effort has been directed for the development of processes which could capture and dump the removed carbon dioxide into an ambient environment.

Various carbon dioxide removal systems which continuously or cyclically capture carbon dioxide and dump into an ambient environment have seen substantial development in recent years. Carbon dioxide removal (CDR) method involves various technologies which remove carbon dioxide from the enclosed space or closed environment. Various technologies that have been used for CDR involve bio-energy with carbon capture and storage, direct air capture, solvent absorption, membrane gas absorption etc. The common methods used for carbon dioxide removal are:

a) Selective permeable membrane;

b) Absorption; and

c) Adsorption.

Membranes like aromatic polyamide are used to remove carbon dioxide, however have its own limitation. In majority of membrane separation techniques, membrane saturation leads to gas losses. Further, the operating cost of the membrane capture system is too high due to regular maintenance of membrane. In addition to that, such membranes are not stable in response to thermal and pressure variation, which makes method ineffective in common practice. Aqueous amines are used for carbon dioxide removal by adsorption techniques.

However issues are there with aqueous amine utilization i.e. its lifetime, susceptibility to degradation through oxidation and corrosion problems.

Adsorption is considered to be one of the more promising ways for efficient capture of Carbon dioxide from surrounding atmosphere. Processes like adsorption of carbon dioxide on phenolic resin based carbon spheres, activated carbons, amine surface^ bonded silica gel, amine functionalized mesoporous silica and amine-enriched fly ash carbon sorbents are used for carbon dioxide removal. Conventional methods for carbon dioxide removal have certain limitations. They do not work in environments where the ambient atmosphere has carbon dioxide partial pressure above the acceptable values in the suit breathing atmosphere. Moreover they are not suited for very large number of occupants in a closely spaced habitat environment and are not of regenerative type. Therefore, there is a need for new improved method and system for removing carbon dioxide from a re-circulating gas stream from a breathable atmosphere in a closed habitat environment such as space suit, space station or cave.

OBJECT OF THE INVENTION

Accordingly, it is the main object of this invention to provide a method and system for carbon dioxide removal. Yet another object of this invention is to provide an improved method and system for removing carbon dioxide from a re-circulating gas stream by means of a carbon dioxide adsorbent resin.

Yet another object of this invention is to provide a method and system for removing C0₂ from a re-circulating gas stream by means of a CO2 adsorbent bed, wherein the gas stream is derived from a breathable atmosphere in a closed habitable environment. .

Yet another object of this invention is to provide an improved method and system for removing carbon dioxide in a closed habitat environment.

Yet another object of this invention is to provide a regenerative carbon dioxide removal system.

Yet another object of this invention is to provide a system and method of carbon dioxide removal for a group of 100-200 or more than 200 persons in a closed habitat environment. Yet another object of this invention is to provide a system and method of carbon dioxide removal where regeneration and flushing is done by stream. Still another object of this invention is to provide a system for desorbing the carbon dioxide from the saturated beds with minimum wastage of energy.

SUMMARY OF THE INVENTION

The present invention provides a system and method comprising of one or more filter beds filled with resin particles which selectively extract C02from the habitat exhaust gas stream. The complete assembly comprises of at least five filter beds. Each filter bed is filled with certain amount of resin. Out of five, two filter beds operate in parallel adsorption mode for initially, while the other two beds during that period are either idle or in regeneration mode. The fifth bed is used for the adsorption of byproduct generated during the process. The regeneration period of the beds is 10-20 minutes with a saturated steam passed from inlet valve connected in each filter resin bed and at a pressure of 0.1-0.2 bar. The beds, after an hour of adsorption, are put on regeneration automatically, one after the other, while the bed regenerated earlier are shifted on adsorption mode. This operation is on continuous basis till the desired level of carbon dioxide is achieved in the enclosed space. BRIEF DESCRIPTION OF THE DRAWINGS Many aspects of the invention can be better understood with reference to the one of more drawings. The components in the drawings are not necessarily to scale, emphasis instead is being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views.

FIG.lisa schematic view of a CO2 removal system of this invention;

FIG. 2 is a schematic view of a working model of C0₂ removal system in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. However, the invention is not limited to the following embodiments, but can be modified in various forms. The embodiments are provided to complete the disclosure of the invention and to completely notify the scope of the invention to those skilled in the art.

As shown in FIG. 1, four parallel filter resin beds 3, 4, 5, 6 are connected to various air inlet valves 8, 9, 10, 11 and air outlet valves 12, 13, 14, 15 respectively. Further, the filter resin beds 3, 4, 5, 6 are also connected with steam inlet valves 16, 17, 18, 19 and steam outlet valves 20, 21, 22, 23 respectively. The air inlet valves 8, 9, 10, 11 are connected with blower 1. The air outlet valves 12, 13, 14, 15 originated from the respective filter resin beds are connected to another filter resin bed 7 through the blower V, which further leads to air outlet vent 28. The steam inlet valves 16, 17, 18, 19 are connected with boiler 2. The steam outlet valves 20, 21, 22, 23 are connected to constant temperature bath 26. The constant temperature bath 26 maintains the ideal temperature for separation of C02 and steam and overflow of it is connected to water reservoir 27. Further, the constant temperature bath 26 is connected to carbon dioxide outlet vent 29 for releasing adsorbed C0₂ into ambient environment.

As shown in Fig-2, the working model of C0₂ removal system comprises of Beds 1, 2, 3, 4 filled with Amine adsorbent resin. Bed 5 is a resin to absorb amine by-product in the air stream. Two blowers (blower 1 and blower 2) are provided in the system for the C02 adsorption beds and two blowers (blower 3 & blower-4) are provided for amine adsorption. The inlet of the blowers is connected to cooling coils to provide cold air to the beds. In the initial cycle Beds 1, 2 in adsorption with blower 1 and blower 3 in working condition, valves A-l, A-3, A-5, A-7, A-8, A-9, A-15 and A-16 are open. In this stage the air from the surrounding passes through the cooling coil and enters Beds 1 and 2 for C02adsorption. The air from the Bed 1 and Bed 2 picks up some amine and enters into Bed 5 through the blower 3 in working condition and passes the air through the Bed 5 for amine adsorption. The adsorption cycle of Beds 1 and 2 take place for 60 minutes and then are saturated with Carbon Dioxide and needs to be regenerated. |n the regeneration cycle the Bed 1 and Bed 2 are subjected to the steam with low pressure, the beds are sprayed with steam for approximately 15 minutes each. During the Bed 1 and Bed 2 regeneration mode Bed 3 and Bed 4 are in adsorption mode, again for an hour. The regeneration is carried out using a boiler of suitable size, the boiler is custom designed to meet the requirement of low pressure steam. The boiler has a two stage pressure reducing valve to reduce the pressure of store steam at 11 kg/cm² to 0.4-0.2 kg/cm², the first pressure reducing valve reduces the pressure from 11 kg/cm² to 4 kg/cm² arid the second pressure reducing valve reduces the pressure from 4 kg/cm² to 0.4-0.2 kg/cm². During the Bed 1 and Bed 2 regeneration and simultaneous adsorption of Bed 3 and Bed 4 valve A-l, A-3, A-5, A-7, A-8, A-9, A-10 close, valve A-2, A-4, A-6, A-ll, A- 12, A-13 and A-

14 open, also for regeneration of Bed 1 and Bed 2 the steam inlet valves to the Bed 1> S-l, S-2 and S-3 are open for 15 minutes for Bed 1 regeneration and steam inlet valves to the Bed 2 S-l, S-4 and S-5 are open for next subsequent 15 minutes for Bed 2 regeneration, the cycle repeats where in again Bed 1 and Bed 2 are operated in adsorption mode and Bed 3 and Bed 4 are in regeneration mode. During the regeneration mode the steam with high content of Carbon Dioxide goes to a constant temperature bath, a constant temperature bath is a mild steel tank filled with water. A cooling coil and immersion, heaters are installed in the constant temperature bath a temperature of 85-90 °C is maintained in the tank by automatically controlling the chilled water flow and operation of heaters. The temperature is maintained as the steam entering the constant temperature bath condenses and pure Carbon Dioxide is exhaust to ambient. A vacuum pump is installed in the exhaust pipeline over the constant temperature bath; the vacuum pump is responsible for exhausting the pure Carbon Dioxide to the ambient.

SPECIFIC MODE FOR CARRYING OUT THE INVENTION

The air inlet valves and air outlet valves of the filter resin beds are disc type valves, on /off type, automatically operated and compatible with all existing state of the art controlling devices. The air inlet and outlet valves remain in open position during the adsorption mode, thus allowing the passage through the resin bed. During the regeneration mode they are closed to disallow traces of steam entering the airline.

The steam inlet and the outlet valves are ball valves, on/off type, automatic in operation and fully compatible with all existing state of the art controlling devices. They remain open in the regeneration mode, whereas they are closed in the adsorption mode.

Initially all the valves are in closed position. At the start of the operation two filter resin beds say 3 and 4 are connected online by opening air inlet valves 8, 9 and air outlet valves 12, 13. Blower 1 draws air from an enclosed space into these beds. Filter resin beds 3 and 4 remain in adsorption mode for an hour.

Filter resin beds3 and 4 are then put offline by the closing valves 8, 9 and 12, 13. Filter resin beds 5 and 6 are now put online by opening their respective air inlet 10, 11 and ^' outlet valves 14, 15. Now beds 5 and 6 are on adsorption mode for an hour.

The saturated beds 3 and 4 are regenerated one after the other each for 10-15 minutes duration by passing saturated steam from the boiler 2 at a pressure of 01-0.2 bar. Bed 3 is first put on regeneration mode by opening valves 16 and 20. Steam enters the bed through valves 16, washes the resin bed and desorption of carbon dioxide is carried out. The steam/hot water along with C02 are collected in a constant temperature bath 26.

After 10-15 minutes the regeneration of bed3 is stopped by closing valves 16 and 20. Bed 4 is now on the regeneration for the next 10-15 minutes by opening valves 17 and 21. The valves 17 and 21 are closed after the regeneration is completed in the stipulated period of 10-1_.5 minutes. Beds 3 and 4 after regeneration are on idle state · for nearly 30-40 minutes. Beds5 and 6 already on adsorption mode get saturated after an hour and are then put offline. The fresh regenerated beds3 and 4 ready for adsorption are put online, Beds 5 and 6 are now regenerated, each for 10-15 minutes duration one after the other. During the adsorption cycle, air passes the beds 3, 4, 5, 6. through valves 12, 13, 14, 15 for C0₂ adsorption but enters filter resin bed 7 for the adsorption of byproducts before being finally released. Thus the said process goes on continuous basis by proper sequential operation of the valves.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is designed to remove excess carbon dioxide generated by human ' beings in an enclosed space. The present invention provides a system and method comprising of at least four bedded assembly for arresting Carbon Dioxide with a fifth bed for removing excessive ammonia in the air stream.

The four beds for removing carbon dioxide comprise of a porous polymer structure coated with amine. The fifth bed comprise of a porous structure coated with a chemical for arresting excessive amine in the air stream. The entire system comprises one or more Cooling coils for cooling down the air, one or more Centrifugal blowers for movement of air, Stainless steel beds (3, 4, 5, 6) for arresting Carbon Dioxide, Stainless steel bed (7) for arresting the pungent smell due to the content of ammonia present in the filtered air from C0₂ beds containing amine based resin, a Boiler for supplying steam to Beds 3, 4, 5, 6, an Isolation valves for controlling the process, a constant temperature bath for maintaining a desired temperature for Carbon Dioxide exhaust, and a vacuum pump for Carbon Dioxide exhaust.

The five bed system of present invention is designed to remove Carbon Dioxide from the enclosed space for at least 200 people on continuous basis where fresh air is not available. It also captures the amine by-product from the filtered air coming put from the C0₂ resin beds. The present C0₂ adsorption system is specifically designed for at least 200 occupants on the regenerative principle. The process of regeneration is by steam at a predefined temperature and pressure, thus having an adequate and optimum efficiency and results; Introduction of an additional bed containing resins which captures the pungent smell due to the traces of amine content present in the filtered air after the air rich in C0₂ content has passed through the amine bed for C0₂ filtration. The present system is designed and constructed to operate on continuous basis fully automatically without any human intervention and centrally controlled by a dedicated Building Management System comprising of high end Programmed Logic Controller (PLC) and precision sensors.

The resin used in the present invention is solid amine specially treated primary amine structure covering the surface of the spherical granules of an ion exchange resin, polystyrene based. Carbon dioxide is bounded to the amines physico-chemically under the ambient atmospheric conditions and is discharged again by means of applied energy. The specific features of these amine-based resins are the simple handling, long time stability of the material, and the purity of the discharged C0₂.ln addition to that, no corrosive liquids/vapors leave the unit, hence a potential contamination of the surrounding atmosphere caused by the conventional system itself is eliminated. Hence_; the resin selected for the present invention has distinct advantages over the conventional carbon dioxide removing media.

The final system developed is a fully automatic system different valve and sensors are installed in the system for process control and data monitoring. The simultaneous adsorption and desorption takes place in the system, the system remain online at all times. A PLC (Programmed Logic Controller) is installed in the system to sequentially operate the valves for subsequent adsorption and desorption cycle continuously on automatic basis. The system works on the time logic of 60 minutes of two beds in adsorption cycle and simultaneously 15-20 minutes of steam, injection for third bed in regeneration consecutively followed by 15-20 minutes of steam injection for fourth bed in regeneration. This logic is loaded into the controller and the system operates as a standalone unit. The adsorption process is represented down as under: Amine +H20 -> (Amine-H20) (Amine-H20) + C02 -> (Amine-H2C03)

During regeneration process the steam breaks the amine-carbon dioxide binding according to the following reaction:

(Amine-H2C03) + Heat -> Amine + H20 + C02

Calculation for equipment selection:

A flow of 1000 LPM gives an average difference of 2800 ppm in an hour.

Percentage of carbon dioxide adsorbed = 0.28%

Quantity of carbon dioxide adsorbed in a total airflow

Of 1000 LPM = 0.28% of 1000 LPM

= 2.8 LPM

Hence, carbon dioxide adsorbed in an hour = 2.8 LPM * 60 MIIM

= 168 LITERS = 0.168 M3

As per ASHRAE standards, C02 produced by a person doing moderate exercise and light work is at the rate of 12.2 ML/SEC.

C02 produced by 200 persons in an hour = 12.2 MLx 3600x 200

= 8.8 M3

Volume of resin filled in a bed height of 190mm and effective diameter of 370 mm

= (/l/4) x D² X H

= (/1/4) x 0.37 ² x 0.190 = 0.0195 M3

= 19.5 LITER say 20 LTRS.

Now,

Two beds operating together, each containing 20 LTRS, adsorb 0.168 M3 of carbon dioxide.

Hence, volume of resin required in each bed to adsorb 8.8 3 of carbon dioxide = 20 LTRS x 8.8 M3

0.168 M3

= 1050 LTRS

Flow rate for the bed height of 190 mm, diameter370mm = 1000 LPM

Removal of C02 from the absorber beds = 2800 PPM

= 0.28%.

In order to maintain the required level of carbon dioxide in an enclosed space, carbon dioxide adsorbed by the beds on time average basis should be equal to the rate of C0₂ emission by 200 persons.

Therefore, average difference of 2800 ppm should be equal to 8.8 M3/HR of carbon dioxide produced by 200 persons.

Thus, 0.28% of airflow 8.8 M3/HR

Total air flow for the actual system 8.8 M3/HR x 100

0.28

3142 CMH

1850 CFM Hence, a flow of 1850 CFM through two beds, each containing 1050 liters of resin shall adsorb 2800 ppm of carbon dioxide on time average basis for an hour, in order to maintain a required level of carbon dioxide in an enclosed space occupied by 200 persons.

Existing flow in the pilot system system = 1000 LP M

= 35 CFM

Scale up of the flow in the actual system = 1850 CFM

35 CFM = 52.85

Now,

QA = /l/4 x DA² x VA = 1850 CFM

QP = /1/4 x DP ² x VP = 35 CFM

Where, DA = diameter of the actual bed,

DP = diameter of the pilot bed = 0.370 MTR

VA = velocity through the actual bed and

VP = velocity through the pilot bed.

The height of the actual bed and air velocity through it should remain the same as in the pilot plant to maintain the similar pressure drop.

Hence, VA = VP.

Therefore, (DA² / DP ²) = 52.85

DA = 52.85 ^½ x DP

= 7.26 x 0.370

= 2.68 MTR

Now, height of the actual bed, LA = 0.190 MTR.

Volume of the actual bed =71/4 x DA² x LA

= /l/4 x 2.68² x 0.190

= 1.072 M3 = 1072 LTRS. If the actual bed diameter, DA is revised to 2.5 MTR (DAR) instead of 2.68 MTR calculated above, then for the same volume, equivalent height (LAR) can be calculated as under:

/1/4 x DAR² x LAR = 1.072 M3.

Thus, LAR = 1.072 M3 x 4

(2.5 MTR) ²x3.142

= 0.218 MTR

= 218 MM = 8.6 INCHES.

If the height calculated above, 8.6 inches is approximated to 10 inches (250 mm), then the volume of each bed can be evaluated as under:

Volume of the bed = /1/4 x DAF² x LAF, where DAF =2.50 MTR

LAF =0.250 MTR

, = 71/4 x 2.50 ² x 0.250

= 1.227 M3 = 1227 LITERS

Say, 1250 LITERS

Hence, the resin volume in each bed is also 1250 liters.

The final data of the resin bed for the actual system can be summarized as under:

Bed diameter = 2.5 MTR.

Bed Height = 0.250 MTR

Resin Volume in each bed = 1250 LTR.

EQUIPMENTS:

The equipment selection was based upon the final design calculation. Brief descriptions of some of the key equipment are given as under: a. RESIN BEDS:

The pilot scheme incorporated cylindrical shaped beds; however for one of sites actual system bed were designed of square construction due to the site constrains involved in it. It however did not comprise on the operating parameters such as velocity of the air, friction drop etc. In fact the designed beds had uniform air distribution to have the maximum contact area with the resin.

The remaining design of the beds for the actual system remains quite similar to the pilot beds. The air inlet was from the bottom whereas its outlet from the top. Similarly, steam inlet to the bed is from the top whereas the drain from the bottom. The resin is held between the pair of stainless steel wire mesh to facilitate the passage of air through the bed. Weld mesh is provided to support, the lower mesh. The body of the beds is constructed of stainless steel SS 304, 16 swg. BLOWER:

The blower selection was very critical, as it was in case of the pilot plant. Pressure drop and the airflow were to govern the selection of the blower. Airflow required for the system was 1850 cfm, however the pressure drop had to be carefully considered for the selection of the blower. The above design calculation was based upon the bed height of 190 mm against a pressure drop of 105 mm of WC. However, this pressure drop measured was for a relatively dry resin, it is of the order of 170-210 mm of WC for wet resin. Moreover, the increased bed height of 250 mm would result in a higher-pressure drop. Eventually, the blower selected should be commensurate to meet the design, parameters in the most critical condition.

Thus the blower selected for the actual system has the following specification: Air flow : 2500 CFM

Static pressure :450 MM of WG. Type : SISW, Backward Curved.

Installed Motor : 11 KW.

A relatively higher static pressure fan was selected to cater for the pressure drop in pipeline also. Two numbers blower were selected. One working and the other as standby. BOILER:

A 100 KW boiler, capable to produce approximately 100 kg of steam in twenty * minutes at a pressure of 0.2 barg was selected for steam heating of the resin beds required for the regeneration cycle.

The boiler cum accumulator selected has an approximate water storage capacity of 1000 liters, complete with quenching tank, feed water tank, feed water pumps, pressure reducing stations and other requisite controls. Both the boiler cum accumulator and the quenching tank are fabricated of 10 mm shell and 12 mm dish end, material carbon steel Grade 2002> suitable for a steam pressure of 11 barg. Controls such as pressure switch, thermostat, safety valve, level controls etc. have been incorporated to make the system functional and automatic in operation. Water supply to the boiler is supplemented by a feed water tank, capacity approximate 1000 liters is cylindrical in shape with flat ends, fabricated out of 3 mm stainless steel, Grade SS 304. The feed water is also accomplished with all the requisite controls such as valve, float switches, strainer. The quenching tank is also fitted with requisite controls and comprises of perforated pipe to spurge the superheated steam coming from the boiler. The steam then released from the quenching tank is in a saturated state and is feeded to the resin beds for regeneration. AUTOMATIC BUTTER FLY VALVES:

These valves have been installed at the air inlet and outlet of the individual bed to allow or disallow the air passage through it, as and when required. The valves shall be remain in open position during the adsorption cycle of the bed while remain closed in the regeneration cycle. These valves are pneumatically operated having double acting actuator, solenoid valve and limit switch and is BMS compatible. The salient specifications of the valves are as under:

Size : 300 mm NB

Body : WCB

Disc : SS 316

Shaft : SS

Seat : RTFE

AUTOMATIC BALL VALVES:

These valves are installed at the steam inlet and outlet of the bed and are also used for ON/OFF application. They remain in open position when the regeneration of the respective resin bed is carried out with steam, while in close position when the beds are in adsorption.

They are also pneumatically operated having double acting actuator, solenoid valve and limit switch for BMS compatibility. These valves are a two-piece construction, full bore, CS body, SS316 ball and stem, PTFE seats with flanged connection. The maker of the valves is Danfoss.

80 mm NB size has been considered for the steam inlet pipe to the bed while 65 mm NB size for the steam outlet.

COOLING COIL:

Two sets of cooling coil have been incorporated in the actual system, at the outlet of each blower to cool the air before it enters the resin bed. The brief specifications of the cooling coil are as under:

Face area : 1100 mm x 600 mm.

Coil size : 12 mm

Row deep 6

HEAT EXCHANGER:

During the regeneration of the resin beds, all the steam does not condenses in the resin bed. A part of it comes out through the bypass line along with the desorbed carbon dioxide. This steam is made to pass through the heat exchanger before it reaches the constant temperature bath.

The heat exchanger used is a shell and tube type having the following basic specifications:

Tube diameter, type : 10 mm, plain copper tubes.

Number of tubes : 80

Number of baffles : 6

Shell : MS, 8 mm thick.

CONSTANT TEMPERATURE BATH:

The condensed steam coming out of the heat exchanger along with the desorbed carbon dioxide is collected in a tank called as constant temperature bath. Here, a constant temperature of around 85-90 °C is maintained with set of heaters, 4.5 KW x 2 numbers and cooling coil, 15mm diameter with 25 turns. The carbon dioxide present in the condensate is separated at this constant temperature.

The height as well as the diameter of the tank are 1000mm and are fabricated out 3mm MS sheet, inside epoxy painted. i. LT PANEL:

An electrical panel is definitely required wherein all the feeders of the electrical parts such as motor, heater etc are housed. A BMS panel separately installed monitors and controls the operating parameters through the hardware communication system.

It should be noted that the remaining structure and working mechanism of the C0₂ removal system is similar to that existing in prior arts and as such no further description shall be given.

It should be understood that the embodiments described above are merely exemplary and that modifications may be made thereto without departing from the scope of the present invention. For example, the C0₂ removal system of the present invention is shown in accordance with the current working model of the system. However, the working model may be modified in accordance with the requirements.

It is to be understood that the present invention is not to be limited to just the preferred embodiment disclosed, but that the invention described herein is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the claims hereafter.

Claims

CLAIMS We claim:

1. An automatic regenerative system for carbon dioxide (C0₂) removal comprising:

a. a first and second group of at least two sorbent beds each and a third group of at least one sorbent bed;

b. a heat exchange system;

c. at least one blower for air movement;

d. at least one boiler for supplying steam to the said first and second group of sorbent beds;

e. isolation valves for controlling the process;

f. a constant temperature bath for maintaining a desired temperature for C0₂ exhaust;

g. a vacuum pump for C0₂ exhaust; and

h. a direct digital control for sequential operation;

wherein:

the said heat exchange system comprises cooling coilsfor cooling down the air;

the said first group of sorbent beds absorbs C0₂ and the second group of sorbent beds desorbs CO2 at a given time, and alternately the said first group of sorbent beds desorbs CO2 and the second group of sorbent beds absorbs CO2;

the said third group of the sorbent beds arrests the byproducts of the sorption process; the said system is completely automatic with no human intervention required to function; and

the said direct digital control comprises of high end Programmed Logic Controller (PLC) and precision sensors.

2. The system for C0₂ removal as claimed in claim 1 wherein, the said sorbent bed is made from material selected from the non limiting group of metals like iron, Aluminium, Copper, or alike, or metal alloys like brass, stainless steel, or alike.

3. The system for C0₂ removal as claimed in claim 1 wherein, the said sorbent bed comprises a surface of spherical polystyrene based ion exchange resin covered by specially treated solid amine.

4. The system for C0₂ removal as claimed in claim 1 wherein, the said sorbent bed of first and second group comprise of a porous polymer structure coated with amine and the said sorbent bed of third group comprises of a porous structure coated with a chemical for arresting excessive amine in the air stream.

5. The system for C0₂ removal as claimed in claim 1 wherein, the said sorbent beds have shapes selected from the non limiting group of spherical, cylindrical, square, rhomboid, trapezoid or alike.

6. The system for C0₂ removal as claimed in claim 1 wherein, the steam generated from the said boiler is fed to resin beds for regeneration process. -,

7. The system for C0₂ removal as claimed in claim 1 wherein, the said isolation valves are installed at the air inlet and outlet of the individual bed to allow or disallow the air passage through it, as and when required, wherein the said valves remain in open position during the adsorption cycle of the bed while remain closed in the regeneration cycle.

8. A method for removing carbon dioxide from a gas stream, the method comprising: a. controllably supplying the gas stream to the first and second groups of sorbent beds containing solid amine sorbent allowing C0₂ absorption and removal from the process air stream;

b. altering the pressure of the sorbent beds by blower to facilitate step a. above; c. heating the sorbent bed that is desorbing C0₂ and cooling the sorbent bed that is absorbing C0₂;

d. removing G0₂ from the sorbent bed desorbing C0₂ as a C0₂ gas stream; and e. removing the byproducts of any of the above steps through sorbent bed comprising of a porous structure coated with a chemical for arresting excessive amine;

wherein: the said supply is controlled by isolation valves to allow absorption and regeneration process to complete in an effective manner; the said method comprises direct digital control through high end Programmed Logic Controller (PLC) and precision sensors; and the process of regeneration is by steam at a predefined temperature and pressure to suit the optimum regeneration process.

9. The method of removing carbon dioxide as claimed in claim 7, wherein the said cycle of sorption of C0₂ at the said first and second group of sorbent beds ranges from 50 - 70 minutes.

10. The method of removing carbon dioxide as claimed in claim 7, wherein the said regeneration process ranges from 5 - 25 minutes.