Efficient use of adsorbents for indoor air scrubbing

Abstract

Some embodiments of the disclosure correspond to, for example, a method for controlling a scrubber containing an adsorbent. The scrubber may be configured to cycle between scrubbing at least one pollutant/gas from a stream of gases with the pollutant/gas being adsorbed onto the adsorbent, and regenerating at least some of the adsorbent and thereby purging at least some of the one pollutant and/or first gas from the adsorbent via a regeneration gas flow. The method may include flowing a stream of gases through the scrubber, the scrubber including the adsorbent and adsorbing at least some of the one pollutant/gas from the stream of gases onto the adsorbent during an adsorption phase over a first time period. The method may also include purging at least a portion of the one pollutant/ gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and cycling therebetween. Some other embodiments of the disclosure, for example, include an air treatment assembly which includes an adsorbent for adsorbing at least on pollutant/gas from a flow of air in one direction, and purging at least some of the adsorbed pollut -ant/gas from the adsorbent with a regeneration air flow to regenerate the adsorbent.

What is claimed is: 
     
         1 . A method for controlling a scrubber containing an adsorbent, the scrubber configured to cycle between scrubbing at least one pollutant and/or first gas from a stream of gases with the at least one pollutant and/or first gas being adsorbed onto the adsorbent, and regenerating at least some of the adsorbent and thereby purging at least some of the at least one pollutant and/or first gas from the adsorbent via a regeneration gas flow, the method comprising:
 flowing a stream of gases through the scrubber, the scrubber comprising the adsorbent;   adsorbing at least some of the one pollutant and/or first gas from the stream of gases onto the adsorbent during an adsorption phase over a first time period;   purging a portion of the at least one pollutant and/or first gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and   cycling between the adsorption phase and the regeneration phase, wherein   one cycle comprises at least an adsorption phase followed by a regeneration phase,   one cycle period comprises the total time elapsed during one cycle,   the at least one pollutant and/or first gas purged from the adsorbent is carried away by the regeneration gas flow, and   a complete regeneration phase comprises a time period for removing substantially all of the pollutant and/or first gas from the adsorbent during the regeneration phase, and   a complete adsorption phase comprises a time period for substantially saturating all the adsorbent during the adsorption; and   limiting at least one of:   the duration of the first time period to a period of time which is less than the complete adsorption phase, and   the duration of the second time period to a period of time which is less than the complete regeneration phase.   
     
     
         2 . The method of  claim 1 , wherein the first time period comprises about 95% of a complete adsorption phase. 
     
     
         3 . The method of  claim 1 , wherein the first time period is about 90% of a complete adsorption phase. 
     
     
         4 . The method of  claim 1 , wherein the first time period is about 80% of a complete adsorption phase. 
     
     
         5 . The method of  claim 1 , wherein the first time period is about 50% of a complete adsorption phase. 
     
     
         6 . The method of  claim 1 , wherein the first time period is about 20% of a complete adsorption phase. 
     
     
         7 . The method of  claim 1 , wherein the first time period comprises about 20% to about 95% of a complete adsorption phase. 
     
     
         8 . The method of  claim 1 , wherein the second time period comprises about 95% of a complete regeneration phase. 
     
     
         9 . The method of  claim 1 , wherein the second time period is about 90% of a complete regeneration phase. 
     
     
         10 . The method of  claim 1 , wherein the second time period is about 80% of a complete regeneration phase. 
     
     
         11 . The method of  claim 1 , wherein the second time period is about 50% of a complete regeneration phase. 
     
     
         12 . The method of  claim 1 , wherein the second time period is about 20% of a complete regeneration phase. 
     
     
         13 . The method of  claim 1 , wherein the second time period comprises about 20% to about 95% of a complete regeneration phase. 
     
     
         14 . The method of  claim 1 , wherein:
 the regeneration phase is terminated upon a regeneration rate R(t r ) of the adsorbent being between about equal to and a predetermined amount less than a productivity p of the complete regeneration phase, wherein 
 productivity  
       
         
           
             
               p 
               = 
               
                 C 
                 
                   
                     T 
                     , 
                   
                 
               
             
           
         
       
        and
 C equals an amount of the pollutant and/or first gas adsorbed by the adsorbent from the stream of gases during one cycle and T is the duration of one cycle period. 
 
     
     
         15 . The method of  claim 1 , wherein:
 the regeneration phase is terminated upon a regeneration rate R(t r ) being between about equal to and about twice a productivity p of the complete regeneration phase, wherein   productivity            p   =     C       T   ,                  and   C equals an amount of the pollutant and/or first gas adsorbed by the adsorbent from the stream of gases during one cycle and T is the duration of one cycle period.   
     
     
         16 . The method of  claim 1 , wherein the pollutant and/or first gas is selected from the group consisting of: carbon dioxide, volatile organic compounds, sulfur oxides, radon, nitrous oxides and carbon monoxide. 
     
     
         17 . The method of  claim 1 , wherein the adsorbent comprises at least one of : an amine supported by a solid, activated carbon, clay, carbon fibers, silica, alumina, zeolites, molecular sieves, titanium oxide, polymer, porous polymers, polymer fibers and metal organic frameworks. 
     
     
         18 . The method of  claim 17 , wherein the supporting solid is at least one of silica, carbon, clay or metal oxide. 
     
     
         19 . The method of  claim 1 , wherein the adsorbent comprises granular solids or pelleted shaped solids. 
     
     
         20 . The method of  claim 1 , wherein the stream of gases comprises air from an enclosed environment, outdoor air, flue gases, or nitrogen with elevated levels of carbon dioxide or organic contaminants, relative to substantially unpolluted air. 
     
     
         21 . The method of  claim 1  wherein the one cycle may further comprise at least one of :
 (i) a first switchover phase prior to the regeneration phase, and (ii) a second switchover phase following the regeneration phase. 
 
     
     
         22 . The method of  claim 21 , wherein the second switchover phase comprises a period of time to bring the adsorbent to a temperature to adsorb the at least one pollutant and/or first gas during the adsorption phase. 
     
     
         23 . The method of  claim 21 , wherein the first switchover phase comprises a period of time to bring the adsorbent to a temperature to release the at least one pollutant and/or first gas from the adsorbent during the regeneration phase. 
     
     
         24 . The method of  claim 1 , wherein prior to streaming the regeneration gas flow the method further includes determining a level of an adsorption efficiency, wherein the adsorption efficiency at any point in time during the one cycle has a value of 1 - C in /C out , wherein C in  is the concentration of the pollutant in the incoming air flow and C out  is the concentration of the pollutant in an outgoing air flow, and wherein an initial adsorption efficiency value is the adsorption efficiency value at the beginning of the adsorption phase,
 wherein the adsorption efficiency value is less than the initial adsorption efficiency value, streaming of the regeneration gas flow over and/or through the adsorbent is performed. 
 
     
     
         25 . A system for controlling a scrubber, the system comprising:
 a scrubber containing an adsorbent, the scrubber configured to cycle between scrubbing at least one pollutant and/or first gas from a stream of gases with the at least one pollutant and/or first gas being adsorbed onto the adsorbent, and purging the at least one pollutant and/or first gas from the adsorbent via a regeneration gas flow;   means for flowing the stream of gases through the scrubber and over and/or through the adsorbent, wherein the adsorbent adsorbs at least one pollutant and/or first gas from the stream of gases during an adsorption phase over a first time period;   means for flowing the regeneration gas flow over the adsorbent for purging a portion of the pollutant and/or first gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and   means for cycling between the adsorption phase and the regeneration phase, wherein   one cycle comprises one adsorption phase followed by one regeneration phase,   one cycle period comprises the total time elapsed during one cycle;   the pollutant and/or first gas purged from the adsorbent is carried away by the regeneration gas flow,   a complete regeneration phase comprises a time period for removing substantially all of the pollutant and/or first gas from the adsorbent during the regeneration phase,   a complete adsorption phase comprises a time period for substantially saturating all the adsorbent during the adsorption, and   the duration of at least one of the following is limited:   the duration of the first time period to a period of time which is less than the complete adsorption phase, and   the duration of the second time period to a period of time which is less than the complete regeneration phase.   
     
     
         26 . The system of  claim 25 , wherein the means for cycling comprises a processor and a non-transitory machine-readable medium storing instructions having computer instructions operating thereon for controlling cycling between the adsorption and regeneration phases. 
     
     
         27 . A computer implemented method for controlling a scrubber containing an adsorbent, the scrubber configured to cycle between scrubbing at least one pollutant and/or first gas from a stream of gases with the at least one pollutant and/or first gas being adsorbed onto the adsorbent, and purging the at least one pollutant and/or first gas from the adsorbent via a purging gas flow, the method comprising:
 flowing a stream of gases through the scrubber, the scrubber comprising an adsorbent;   adsorbing at least one pollutant and/or first gas from the stream of gases onto the adsorbent during an adsorption phase over a first time period,   purging a portion of the at least one pollutant and/or first gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and   cycling between the adsorption phase and the regeneration phase, wherein   one cycle comprises one adsorption phase followed by one regeneration phase,   one cycle period comprises the total time elapsed during one cycle; 
 the at least one pollutant and/or first gas purged from the adsorbent is carried away by the regeneration gas flow, and
 a complete regeneration phase comprises a time period for removing substantially all of the pollutant and/or first gas from the adsorbent during the regeneration phase, 
 a complete adsorption phase comprises a time period for substantially saturating all the adsorbent during the adsorption; and 
 limiting at least one of: 
 the duration of the first time period to a period of time which is less than the complete adsorption phase, and 
 the duration of the second time period to a period of time which is less than the complete regeneration phase, 
 wherein at least one of the above is performed by at least one processor. 
 
     
     
         28 . A system for controlling a scrubber containing an adsorbent, the scrubber configured to cycle between scrubbing at least one pollutant and/or first gas from a stream of gases with the at least one pollutant and/or first gas being adsorbed onto the adsorbent, and purging the at least one pollutant and/or first gas from the adsorbent via a regeneration gas flow, the system comprising at least one processor and a non-transitory machine-readable medium storing instructions that, when executed by the at least one processor, perform the method comprising:
 flowing a stream of gases over and/or through the adsorbent, wherein the adsorbent adsorbs at least some of the at least one pollutant and/or first gas from the stream of gases during an adsorption phase over a first time period;   purging a portion of the at least one pollutant and/or first gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and   cycling between the adsorption phase and the regeneration phase, wherein   one cycle comprises one adsorption phase followed by one regeneration phase,   one cycle period comprises the total time elapsed during one cycle,   the at least one pollutant and/or first gas being purged from the adsorbent is carried away by the regeneration gas flow, and   a complete regeneration phase comprises a time period for removing substantially all of the at least one pollutant and/or first gas from the adsorbent during the regeneration phase,   a complete adsorption phase comprises a time period for substantially saturating all the adsorbent during the adsorption, and   limiting at least one of:   the duration of the first time period to a period of time which is less than the complete adsorption phase, and   the duration of the second time period to a period of time which is less than the complete regeneration phase.   
     
     
         29 . A method for reducing the level of at least one pollutant contained in indoor air from a human-occupied, enclosed environment, the method comprising:
 providing an air treatment assembly including at least one type of adsorbent, the adsorbent configured for capturing at least one pollutant entrained in an indoor air flow from the enclosed environment and regenerating upon exposure to a regenerating gas flow;   streaming the indoor air flow over and/or through the adsorbent in a first direction such that the adsorbent captures at least some of the at least one pollutant from the indoor air flow, wherein after being flowed over and/or through the adsorbent, the air flow comprises a scrubbed air flow; and   streaming the regeneration gas flow over and/or through the adsorbent in a second direction opposite to the first direction, such that the regeneration gas flow regenerates at least some of the adsorbent and purges at least some of the at least one pollutant from the adsorbent.   
     
     
         30 . The method of  claim 29  where there are at least two adsorbents such that the streaming indoor air flows through a first adsorbent and subsequently through a second adsorbent, and that as a result of the reversal of the flow direction during regeneration, substances purged from the first adsorbent do not flow across the second adsorbent. 
     
     
         31 . The method of  claim 29  where pollutants are released from the adsorbent during regeneration and may accumulate in the air treatment assembly or air conduits attached to it, and as a result of the reversal of the flow direction during regeneration, the released pollutants are substantially prevented from accumulating downstream from the adsorbent and accumulate substantially in sections of the air treatment assembly that are upstream from the adsorbent,
 the air treatment assembly comprising an inlet for indoor air flowing through the adsorbent; and 
 upstream the adsorbent being in greater proximity to the inlet than downstream the adsorbent. 
 
     
     
         32 . The method of  claim 29 , wherein the pollutant and/or first gas is selected from the group consisting of: carbon dioxide, volatile organic compounds, sulfur oxides, radon, nitrous oxides and carbon monoxide. 
     
     
         33 . The method of  claim 29 , wherein the adsorbent comprises at least one of an amine supported by a solid, activated carbon, clay, carbon fibers, silica, alumina, zeolites, molecular sieves, titanium oxide, polymer, porous polymers, polymer fibers and metal organic framework. 
     
     
         34 . The method of  claim 33 , wherein the supporting solid is at least one of silica, carbon, clay or metal oxide. 
     
     
         35 . The method of  claim 29 , wherein the adsorbent comprises granular solids or pelleted shaped solids. 
     
     
         36 . A computer implemented method for reducing the level of at least one pollutant contained in indoor air from an enclosed, human-occupied environment, the method comprising:
 streaming an indoor air flow over and/or through an adsorbent provided within an air treatment assembly in a first direction, the indoor air flow containing at least one pollutant from inside the enclosed environment, such that the adsorbent captures at least some of the at least one pollutant from the indoor air, wherein after being flowed over and/or through the adsorbent, the air flow comprises a scrubbed air flow;   determining a level of an adsorption efficiency, wherein the adsorption efficiency at any point in time during the one cycle has a value of 1 - C in C out , wherein C in  is the concentration of the pollutant in the incoming air flow and C out  is the concentration of the pollutant in an outgoing air flow, and wherein an initial adsorption efficiency value is the adsorption efficiency value at the beginning of the adsorption phase,   wherein the adsorption efficiency value is less than the initial adsorption efficiency value, and   streaming a regeneration air flow through the air treatment assembly and over and/or through the adsorbent in a second direction opposite to the first direction, such that the regeneration air flow regenerates at least some of the adsorbent and purges at least some of the at least one pollutant from the adsorbent,   wherein at least one of the above is performed by a processor.   
     
     
         37 . A system for reducing the level of at least one pollutant contained in indoor air from an enclosed, human-occupied environment, the method comprising:
 an air treatment assembly including an adsorbent, the adsorbent configured for capturing at least one pollutant entrained in an indoor air flow and regenerating upon exposure to a regenerating gas flow; and   streaming means for:
 streaming the indoor air flow over and/or through the adsorbent in a first direction, such that the adsorbent captures at least some of the at least one pollutant from the indoor air flow, and 
 streaming the regeneration air flow over and/or through the adsorbent in a second direction opposite to the first direction, such that the regeneration gas flow regenerates at least some of the adsorbent and purges at least some of the at least one pollutant from the adsorbent. 
   
     
     
         38 . A system for reducing the level of at least one pollutant contained in indoor air from an enclosed, human-occupied environment, the system comprising:
 an air treatment assembly including an adsorbent, the adsorbent configured for capturing at least one pollutant entrained in an indoor air flow and regenerating upon exposure to a regenerating gas flow;   streaming means for streaming the indoor air flow over and/or through the adsorbent in a first direction, and/or for streaming the regeneration gas flow over and/or through the adsorbent in a second direction opposite to the first direction;   at least one processor; 
 a non-transitory machine-readable medium storing instructions that, when executed by the at least one processor, perform the method comprising:
 streaming the indoor air over and/or through the adsorbent in the first direction such that the adsorbent captures at least some of the at least one pollutant from the indoor air; and 
 determining a level of an adsorption efficiency, wherein the adsorption efficiency at any point in time during the one cycle has a value of 1 - C in /C out , wherein C in  is the concentration of the pollutant in the incoming air flow and C out  is the concentration of the pollutant in an outgoing air flow, and wherein an initial adsorption efficiency value is the adsorption efficiency value at the beginning of the adsorption phase, wherein the adsorption efficiency value is less than the initial adsorption efficiency value, streaming of the regeneration gas flow over and/or through the adsorbent is performed. 
 
     
     
         39 . A method for reducing the level of at least one pollutant contained in indoor air from an enclosed, human-occupied environment, the method comprising:
 providing an air treatment assembly including an adsorbent, the adsorbent configured for capturing at least one pollutant entrained in an indoor air flow from the enclosed environment and regenerating upon exposure to a regenerating gas flow;   streaming the indoor air flow over and/or through the adsorbent in a first direction such that the adsorbent captures at least some of the at least one pollutant from the indoor air flow, wherein the streaming of the indoor air flow over and/or through the adsorbent comprises an adsorption phase; and   streaming the regeneration gas flow over and/or through the adsorbent in a second direction opposite to the first direction, such that the regeneration air flow regenerates at least some of the adsorbent and purges at least some of the at least one pollutant from the adsorbent, wherein the streaming of the regeneration gas flow over and/or through the adsorbent comprises a regeneration phase,   cycling between the adsorption phase and the regeneration phase, wherein   one cycle comprises an adsorption phase followed by a regeneration phase,   one cycle period comprises the total time elapsed during one cycle;   the at least one pollutant purged from the adsorbent is carried away by the regeneration gas flow, and   a complete regeneration phase comprises a time period for removing substantially all of the at least one pollutant from the adsorbent during the regeneration phase, and and   a complete adsorption phase comprises a time period for substantially saturating all the adsorbent during the adsorption; and   limiting at least one of:   the duration of the first time period to a period of time which is less than the complete adsorption phase, and   the duration of the second time period to a period of time which is less than the complete regeneration phase.   
     
     
         40 . The method of  claim 39 , wherein prior to streaming the regeneration gas flow the method further includes determining a level of an adsorption efficiency, wherein the adsorption efficiency at any point in time during the one cycle has a value of 1 - C in /C out , wherein C in  is the concentration of the pollutant in the incoming air flow and C out  is the concentration of the pollutant in an outgoing air flow, and wherein an initial adsorption efficiency value is the adsorption efficiency value at the beginning of the adsorption phase, wherein the adsorption efficiency value is less than the initial adsorption efficiency value, streaming of the regeneration gas flow over and/or through the adsorbent is performed. 
     
     
         41 . The method of  claim 40  wherein the adsorption efficiency value is at least about 20% less than the initial adsorption efficiency value. 
     
     
         42 . The method of  claim 40  wherein the adsorption efficiency value is at least about 30% less than the initial adsorption efficiency value. 
     
     
         43 . The method of  claim 40  wherein the adsorption efficiency value is at least about 50% less than the initial adsorption efficiency value. 
     
     
         44 . The method of  claim 40  wherein the adsorption efficiency value is at least about 80% less than the initial adsorption efficiency value.