EP3349877A1 - Système et procédé de filtration de gaz - Google Patents

Système et procédé de filtration de gaz

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Publication number
EP3349877A1
EP3349877A1 EP16770469.1A EP16770469A EP3349877A1 EP 3349877 A1 EP3349877 A1 EP 3349877A1 EP 16770469 A EP16770469 A EP 16770469A EP 3349877 A1 EP3349877 A1 EP 3349877A1
Authority
EP
European Patent Office
Prior art keywords
filter
gas
air
target gas
concentration
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP16770469.1A
Other languages
German (de)
English (en)
Inventor
Johan Marra
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips NV filed Critical Koninklijke Philips NV
Priority claimed from PCT/EP2016/071955 external-priority patent/WO2017046321A1/fr
Publication of EP3349877A1 publication Critical patent/EP3349877A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/30—Controlling by gas-analysis apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/72—Organic compounds not provided for in groups B01D53/48 - B01D53/70, e.g. hydrocarbons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/45—Gas separation or purification devices adapted for specific applications
    • B01D2259/4508—Gas separation or purification devices adapted for specific applications for cleaning air in buildings

Definitions

  • the invention relates to methods and apparatus for filtering gaseous pollutants from a gas to be filtered.
  • Air pollution sources are encountered both outdoors (e.g. from motor vehicles and industry) and indoors (from cooking, smoking, candle burning, incense burning, outgassing building/decoration materials, use of outgassing waxes, paints, polishes etc.).
  • the pollution level indoors is often higher than outdoors.
  • many people reside most of their time indoors and may thus be almost continuously exposed to unhealthy levels of air pollution.
  • HVAC heating, ventilation and air conditioning
  • activated carbon filters For removing polluting gases from air, use of often made of activated carbon filters which are capable of adsorbing/removing many volatile organic hydrocarbon gases (VOCs) and several inorganic gases (N0 2 , 0 3 , radon) from air.
  • the activated carbon material is usually present as granules that are contained in an air-permeable filter frame structure.
  • concentration can increase to well above the clean air guideline concentrations for formaldehyde (0.05 mg/m 3 at 8 hour exposure, 0.10 mg/m 3 at 1 hour exposure) when the room is poorly ventilated.
  • High ventilation conditions achieved by opening windows and doors are not always feasible due to outdoor weather conditions, an uncomfortable outdoor temperature, and/or safety considerations.
  • activated carbon For removing formaldehyde and/or small acidic gases (S0 2 , acetic acid, formic acid, HNO x ) from air, activated carbon as such is also not very effective. Instead, use can be made of impregnated filter materials capable of chemically absorbing these gases from air. Absorption can occur via acid-base interactions or through a chemical condensation reaction. Activated carbon granules can be used as the impregnation carrier, but also hydrophilic fibrous cellulose paper, glass-fiber sheet material, and porous ceramic honeycomb structures are suitable for this purpose.
  • US 2015/0202565 Al discloses an air purification system for indoor and in- vehicle air cleaning.
  • the system consists of particle filter, toxic chemical and odor absorber, particle and chemical pollutant gas sensors, and a smart control unit with internet-enabled data terminal connected with user's smart devices via Wi-Fi or cellular 3G and 4G LTE.
  • EP 1 402 935 Al a method and an arrangement are disclosed for monitoring the operational status of an apparatus for adsorbing pollutants from a source of polluted gas and desorbing said pollutants to an internal combustion engine.
  • an indoor air cleaner re-circulates the air in a given enclosure through a filter stack comprising the formaldehyde absorption filter.
  • formaldehyde absorption filters suffer from their limited lifetime.
  • the functionality of the formaldehyde absorption filter relies on the presence of a chemical impregnant, such as tris-hydroxymethyl-aminomethane, in the filter that is capable of absorbing formaldehyde gas via a chemical condensation reaction.
  • the 1-pass formaldehyde absorption efficiency of the filter is also found to depend on the relative humidity (RH) and on the state of filter loading with absorbed formaldehyde. Because the overall absorbed amount of formaldehyde in the filter depends on the details of the filter structure, the filter impregnation, and the filter's exposure history to air of varying relative humidity and formaldehyde levels, and wherein also the airflow through the filter is often allowed to vary in the course of time, it is difficult to predict the effectiveness of the absorption filter at any moment in time with respect to its ability to clean the air from formaldehyde gas.
  • Desirable would be a filter and filtering method suitable for removing gaseous pollutants from air, in particular formaldehyde, which prolongs the filter lifetime while also enabling sufficient filtering efficiency to be ensured over time in an energy-efficient manner and the signaling of moment at which the filter should be replaced for a fresh filter (i.e, the end of the filter life).
  • a filtration system for removing a target gaseous pollutant from a gas to be filtered in an indoor space, the filtration system comprising:
  • a sensor arrangement which comprises a gas sensor for sensing a concentration of a target gas in the indoor space;
  • an air cleaner which comprises a filter for filtering the target gas from the gas to be filtered, and a ventilation system for controllably driving air through the filter;
  • controller for controlling the ventilation system air flow setting, wherein the controller is adapted, based on current sensor arrangement signals, and a previous history of the sensor arrangement signals, and previous ventilation system air flow settings, to:
  • This system evaluates the use and performance of a gas filter, by monitoring over time the target gas concentration in the indoor space and the ventilation settings (e.g. fan speed). In this way, the loading of the filter with target gas resulting from the filtering is determined. This enables the filter end of life to be determined accurately.
  • the ventilation settings e.g. fan speed
  • the sensor arrangement further comprises a temperature sensor, and a relative humidity sensor. This allows for a more accurate control of the filtration system.
  • the filter comprises a reversible absorption filter or a reversible adsorption filter.
  • the controller is further adapted to:
  • the user may be notified of whether filter regeneration is taking place or whether air filtering is taking place. This allows the user to take appropriate action, e.g. ventilating the room.
  • the user interface may be a display which is part of the filtration system.
  • the filtration system may comprise wireless components configured to notify a user wirelessly, for example via a device of the user, for example a smartphone.
  • the controller may aim to maintain both the target gas concentration in the indoor space and the target gas concentration at the filter exit to be within desired levels. This enables the filter regeneration to be controlled for example by keeping the ventilation system running even when the target gas concentration in the indoor space is below a desired minimum level.
  • the historical (partial) filter regenerations are also evident from the previous history so that the end of filter life determination takes account of previous filter use as well as previous filter regenerations.
  • the periodic regeneration of the reversible filter takes place through target gas desorption and this can be allowed to take place under conditions of high indoor space ventilation with outdoor air, as characterized by a low indoor target gas concentration.
  • the gas filter instead cleans the indoor air, namely when the gas sensor system senses an elevated indoor gas concentration.
  • the system may operate in an automatic mode with a minimized expense of energy, to continuously aim to obtain a sufficiently low indoor target gas concentration while retaining as much as possible a sufficient functionality of the gas filter. This enables an extended functional life of the gas filter, thereby reducing or even avoiding the need for filter replacement.
  • the controller may further be adapted to switch off the ventilation system when it is determined that:
  • the filter has reached its end of life; or the gas sensor reading is below a first threshold and the determined
  • concentration of the target gas in the air flow exiting the air cleaner is below a second threshold.
  • the gas filter When the gas filter has reached the end of its life, its filtering performance towards the target gas has become too low to be acceptable and the air cleaner comprising the gas filter should not be used any longer.
  • the gas sensor reading and the determined target gas concentration exiting the gas filter are both low, air filtering is not needed and filter regeneration is not needed, so that energy can be saved by turning off the ventilation system comprised in the air cleaner.
  • the controller may be further adapted to:
  • the controller may be further adapted to:
  • the controller may be further adapted to:
  • This third threshold may be a maximum permitted level, which indicates that the degree of filter loading with target gas has exceeded a maximum level above which the filter has become unable to effectively remove the target gas from the air in the indoor space. The gas filter should then no longer be used.
  • the controller may be further adapted to:
  • Additional ventilation with outdoor air wherein a low (or zero) target gas concentration is present, may be desired at times of high concentration of the target gas in the indoor space, or to make the filter regeneration more effective.
  • the gas sensor may comprise a formaldehyde sensor, and the reversible gas filter then comprises a reversible absorption formaldehyde filter.
  • the invention may however also be applied to reversible adsorption filters, such as activated carbon or zeolite adsorption filters, and these may be used for the filtering of volatile organic compounds (VOCs).
  • VOCs volatile organic compounds
  • the gas sensor comprises a formaldehyde sensor, wherein the target gas is formaldehyde, wherein the filter comprises a reversible formaldehyde filter, and wherein the degree of filter loading ⁇ ( ⁇ ) with
  • ⁇ represents the absorbed amount of formaldehyde gas
  • (j) c represents the airflow rate at the pertaining ventilation system air flow setting
  • RH represents the relative humidity in the indoor space
  • T represents the temperature in the indoor space
  • c gas represents the concentration of a target gas in the indoor space
  • Z( c (t.),i?H(t.),r(t.),r(t._ 1 ),c gai (t ! ) represents the formaldehyde concentration in the air exiting the filter.
  • Examples in accordance with another aspect of the invention provide a method of controlling a filtration system for removing a target gaseous pollutant from a gas to be filtered in an indoor space, comprising:
  • the air cleaner comprising a filter for filtering the target gas from the gas to be filtered, and the ventilation system for controllably driving air through the absorption filter
  • control of the ventilation system comprises, based on current sensed values, and a previous history of the sensed values, and previous ventilation system air flow settings:
  • the filter comprises a reversible absorption filter or a reversible adsorption filter, and the method further comprises:
  • the method may comprise a step of notifying the user of whether filter regeneration is taking place or whether air filtering is taking place, for example via a user interface. This allows the user to take appropriate action, e.g. ventilating the room or not.
  • the notification may be displaying a message on a display of the filtration system or wirelessly transmitting a message to a device of the user, e.g. a smartphone.
  • the method also enables the lifetime to be maximized by controlling filter usage and regeneration over time.
  • the method may further comprise steps to make the determinations as outlined above, as well as temperature and/or relative humidity sensing steps.
  • the method may be implemented by a computer program comprising code means for implementing an algorithm.
  • Fig. 1 shows a gas filtration system
  • Fig. 2 shows a gas filtration method
  • the invention provides a gas filtration system which has a gas sensor for sensing a concentration of a target gas, a temperature sensor and a relative humidity sensor.
  • An air cleaner is controlled by a controller which makes use of the current sensor signals as well as the previous history of the sensor signals and the previous air cleaner flow settings. In this way, it becomes possible to determine a degree of filter loading with the target gas, and thereby determine when the filter has reached its end of life. If a reversible filter is used, the concentration of the target gas in the air flow exiting the air cleaner can be determined (if the ventilation system (e.g. the fan) comprised in the air cleaner is turned on). It can thus be determined when filter regeneration is taking place and when air filtering is taking place, and the end of life determination takes into account previous regeneration cycles.
  • the ventilation system e.g. the fan
  • This system evaluates the use of a gas filter, by monitoring over time the target gas concentration, the relative humidity, the temperature, and the air cleaner settings.
  • the controller may aim to maintain both the target gas concentration in the indoor space and the gas concentration at the filter exit to be within desired levels. It provides an accurate determination of the end of life of the filter and in some examples also providing controlled filter regenerations when needed and when the indoor air quality conditions are suitable for that purpose.
  • the invention is of particular interest for removing formaldehyde gas from an indoor space, and an example will now be given of a reversible gas filtration system specifically for formaldehyde gas.
  • Fig. 1 shows the gas filtration system 10. It comprises a sensor arrangement 12, which comprises a gas sensor 14 for sensing a concentration of formaldehyde gas in the indoor space (c gas ), a temperature sensor 16 for providing a temperature reading (T) and a relative humidity sensor 18 for providing a relative humidity reading (RH).
  • a sensor arrangement 12 which comprises a gas sensor 14 for sensing a concentration of formaldehyde gas in the indoor space (c gas ), a temperature sensor 16 for providing a temperature reading (T) and a relative humidity sensor 18 for providing a relative humidity reading (RH).
  • pre-set average values are used for temperature and relative humidity instead of sensed values.
  • An air cleaner 20 comprises a reversible absorption filter 22 for filtering the formaldehyde from the air and a ventilation system 24, such as a fan, for controllably driving air through the filter 22.
  • a controller 26 controls the ventilation system air flow setting ⁇ 0 . At the simplest level, there is only on/off control. However, more preferably, there is control of the air flow rate through the filter.
  • the controller 26 receives the current sensor signals (RH, T, c gas ) and the previous history of the sensor arrangement signals and the previous ventilation system air flow settings ( ⁇ 0 ). It stores this historical data, and uses it to determine various parameters discussed below. The controller implements an algorithm to provide the data analysis.
  • the controller controls an output device 28 which is used to deliver information about the filtration system and the air quality in the room.
  • the output device issues recommendations about the desired room ventilation level with outdoor air.
  • the output device may be a part of the system, or it may be a remote device such as a smartphone or tablet of the user of the system, to which signals are sent (wirelessly) by the controller.
  • the filtration system enables, whenever needed, the periodic (partial) regeneration of the formaldehyde absorption filter through desorption of formaldehyde under conditions of high ventilation with outdoor air and thus a low indoor formaldehyde concentration level.
  • the desorbed formaldehyde gas is thereby displaced from the indoor space to outdoors by the ventilation air.
  • the formaldehyde concentration in outdoor air is usually very low if not zero. Applying a high ventilation level with outdoor air is feasible when the outdoor air temperature is at a comfortable level, and when acceptable outdoor weather conditions exist. Under low ventilation conditions, the filtration system is enabled to clean the indoor air from the formaldehyde emitted from indoor sources in case the formaldehyde gas sensor system senses an elevated indoor concentration.
  • the filtration system is configured such that, in an automatic mode, it operates such as to aim for a sufficiently low indoor formaldehyde concentration at all times, while at the same time retaining a sufficient functionality of the absorption filter.
  • a further aim is that these actions are carried out at the expense of a minimized amount of energy. This enables the automatic and sustainable realization of a long or even indefinite functional life of the gas absorption filter.
  • the system is for example to be placed in a room to clean the air therein from formaldehyde whenever the need arises.
  • the system can be based on known sensors and filter designs, for example as disclosed in WO 2013/008170 and US 6071479.
  • the formaldehyde sensor is capable of selectively measuring the ambient formaldehyde gas concentration c gas over the course of time.
  • the air cleaner 20 comprises a formaldehyde absorption filter 22 wherein formaldehyde is reversibly absorbed from air.
  • Reversible absorption means that the filter removes formaldehyde from the air in the room via absorption when a relatively high formaldehyde concentration is present in the air under the condition that only a relatively small amount of absorbed formaldehyde gas is already absorbed in the filter. This can happen when the ventilation level in the room is low.
  • the filter releases formaldehyde gas back to the air when a relatively low formaldehyde concentration is present in the air while a relatively large amount of absorbed formaldehyde is already present in the filter. This can happen when the room is well ventilated, for example when at least one of its windows is open.
  • the desorbed formaldehyde is thereby readily displaced from indoors to outdoors together with the ventilation air so that it does not lead to a marked increase in the indoor formaldehyde concentration.
  • the absorption reversibility is akin to a chemical equilibrium between two species, in this case the non-absorbed formaldehyde concentration (c gas ) in air and the amount of formaldehyde (r(c gas )) that can be absorbed in the filter at the concentration c gas in air.
  • the gas concentration c gas is expressed in the unit “g/m 3 "
  • the absorbed amount r(c gas ) is expressed in the unit "g" (gram).
  • the chemical equilibrium constant Cf determines the equilibrium partitioning of the species between the absorbed state (T(c gas )) and the non- absorbed state (c gas ) according to:
  • the unit of Cf is therefore "m 3 ".
  • the chemical equilibrium constant Cf is the analogue of the capacitance of an electrical capacitor where Cf represents the ratio of the charge Q on the capacitor plates and the voltage drop V between the capacitor plates. As such, Cf may also be considered to represent the filter capacitance for formaldehyde. At equilibrium, a higher c gas allows a higher value of r(c gas ) to be reached.
  • a reversible formaldehyde absorption filter is disclosed in US 6 071 479. It features a corrugated paper structure wherein the porous paper material is impregnated with a mixture of a base (KHCO3), a humectant (Kformate), and an organic amine (Tris-hydroxymethyl-amino methane (Tris)).
  • a base KHCO3
  • Kformate a humectant
  • Tris Tris-hydroxymethyl-amino methane
  • the filter impregnation is carried out with an aqueous impregnant solution comprising:
  • KHCO3 at a concentration preferably chosen in the 5 - 15% w/w range
  • Kformate at a concentration preferably chosen in the 5 - 20% w/w range; Tris at a concentration preferably chosen in the 5 - 25% w/w range.
  • a fixed volume Vi mp of the impregnant solution is incorporated in the filter's paper structure per unit filter volume, followed by drying.
  • the absorption filter capacitance Cf is proportional to Vimp, the relative humidity, and the filter volume.
  • Cf becomes also dependent on ⁇ .
  • the filter can alternatively have a parallel-plate structure, a honeycomb structure, or a granular structure.
  • a formaldehyde absorption filter may be considered of thickness L and filter face area Amter that is impregnated with a volume Vi mp of impregnant solution of a certain fixed composition per unit filter volume.
  • n is a process parameter depending, amongst others, on RH, T and ⁇
  • ⁇ 0 (a fresh absorption filter)
  • the process parameter "n" can therefore be determined from the measurement of Cexit downstream from a fresh filter according to:
  • the reversible absorption filter turns into an irreversible absorption filter from which no desorption is possible.
  • Filter regeneration is then no longer possible, and the process parameter "n" becomes a function of ⁇ .
  • acidic gases e.g., S0 2 , FiNO x , carboxylic acids
  • alkaline gases e.g., NH 3 , organic amines
  • the above-mentioned reversible formaldehyde absorption filter acts as an irreversible alkaline-impregnated filter towards acidic gases.
  • the parameters RH, T and c gas are obtained at any time as input data from the formaldehyde sensor and the RH,T sensor system.
  • the flow rate ⁇ through the filter is obtained at any time from the recorded airflow settings of the air cleaner 20.
  • the algorithm enables the delivery of various messages to the user.
  • an air quality reading indication for example with three levels 1 (good) to 3 (poor)
  • the controller provides electronic feedback to the air cleaner to control/change its ON/OFF status and to set its airflow rate ⁇ in order to optimally meet the requirements of clean indoor air and the availability of a sufficiently functional gas absorption filter at all times at the expense of only a minimized energy consumption.
  • the algorithm comprises a decision protocol that involves the use of several pre-defined formaldehyde concentrations. These are defined as:
  • Ci n ,mm 0.05 mg/m 3 .
  • Cin,ma X a high indoor formaldehyde concentration, which can, for example, be set at about 5 times the value of Ci n , m i n . At c gas > Ci n , max , extra ventilation with outdoor air is recommended.
  • air cleaner ON This indicates that the gas filter output is in an acceptable concentration range, and indeed is lower than at the input. There is a medium concentration in the indoor space with a medium air quality (level 2) so the air cleaner is used. if Cexit, min ⁇ Cexit ⁇ C e xit,max
  • air cleaner ON This indicates that the gas filter output is in an acceptable concentration range, but higher than (or equal to) that at the input.
  • Filter regeneration can take place by keeping the air cleaner on, in order to reduce c ex it-
  • the top of each cell has a cell number.
  • the algorithm moves between cells in the manner explained below.
  • the left column represents clean air in the space
  • the middle column represents medium air pollution
  • the right column represents poor quality air.
  • the top row represents a clean air filter
  • the middle row represents a partially loaded filter
  • the bottom row represents a filter that is highly loaded with absorbed gas.
  • the aim of the algorithm is to move to cell 1 if possible, which corresponds to low concentration in the indoor space and a regenerated filter.
  • Cell 3 proceeds to cell 2 which proceeds to cell 1. This takes place because the air cleaning reduces the pollution level over time.
  • Cell 6 proceeds to cell 8 when the initial air cleaning has taken effect.
  • Cell 11 moves to cell 10 and to cell 9 if the user follows the advice of increasing the ventilation with outdoor air.
  • the air cleaner is turned off because the filter is recognized to emit an unacceptably high formaldehyde concentration with c ex it ⁇ Cexit,max.
  • the filter itself becomes an unacceptable pollution source. It is then also ensured that the air cleaner remains switched off with the recommendation to replace the filter.
  • the air cleaner can be switched off in order to save energy.
  • the above decision protocol is made only on the basis of the indoor formaldehyde pollution level and the status of the formaldehyde absorption filter. It is recognized that the formaldehyde pollution level is only part of the overall indoor air pollution problem.
  • Fig. 2 shows a method of controlling a filtration system for removing a target gaseous pollutant from a gas to be filtered in an indoor space.
  • the system makes use of a ventilation system of an air cleaner which comprises a reversible absorption filter for filtering the target gas from the air, and the ventilation system is for controllably driving air through the absorption filter.
  • the method comprises:
  • step 30 sensing a concentration of a target gas in the indoor space, a temperature in the indoor space and the relative humidity in the indoor space.
  • step 32 determining a degree of filter loading with the target gas, and thereby determining a concentration of the target gas in the air flow exiting the air cleaner if the ventilation system of the air cleaner is turned on;
  • step 34 determining when filter regeneration is taking place and when air filtering is taking place
  • step 36 determining when the filter has reached its end of life. In dependence on the different determinations, information is provided to the user in step 38, in the form of messages, alerts, or advisory information.
  • the ventilation system of the air cleaner is controlled in step 40.
  • the above example is based on a reversible formaldehyde filter.
  • the invention may be applied to other reversible filters.
  • an activated carbon filter or a zeolite filter may be used for adsorbing volatile organic hydrocarbon gases (VOCs) from air.
  • VOCs volatile organic hydrocarbon gases
  • the required gas sensor is then a VOC sensor capable a sensing (a range of) VOCs that can be adsorbed on and desorbed from the activated carbon or zeolite adsorbents.
  • VOC sensors are a photo-ionization detector (PID) and a metal- oxide semiconductor (MOS) sensor.
  • PID photo-ionization detector
  • MOS metal- oxide semiconductor
  • irreversible absorption filters may also be used. Filter regeneration through gas desorption is then no longer possible, but, with a suitable gas sensor, the approach described above can still be used to detect accurately the end of filter life. Status messages and smart ventilation control in the context of filter regeneration are then no longer relevant.
  • the general tracking algorithm for a reversible filter used for calculating c ex it, also applies to the irreversible filter, but of course the details of the function Z will be different.
  • the decision protocol in the Table above with cells 1 - 11 still holds but, Cexit ⁇ c gas in all cases for an irreversible filter, so that the events in cells 4, 5, 9, and 10 will never occur. The other events are still possible and the relayed status messages,
  • the described reversible formaldehyde filter for example acts simultaneously as an irreversible absorption filter for acidic gases. Status messages concerning the degree of filter loading and the end-of- filter life with respect to acidic gases can thus still be given.
  • the invention is of interest for indoor air cleaners, ventilation or HVAC (heating, ventilation and air conditioning systems) and other air handling units.
  • HVAC heating, ventilation and air conditioning systems
  • other air handling units In the case of an HVAC system, the ventilation recommendations explained above may be implemented automatically.
  • controllers can be implemented in numerous ways, with software and/or hardware, to perform the various functions required.
  • a processor is one example of a controller which employs one or more microprocessors that may be programmed using software (e.g., microcode) to perform the required functions.
  • a controller may however be implemented with or without employing a processor, and also may be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions.
  • controller components that may be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).
  • ASICs application-specific integrated circuits
  • FPGAs field-programmable gate arrays
  • a processor or controller may be associated with one or more storage media such as volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM.
  • the storage media may be encoded with one or more programs that, when executed on one or more processors and/or controllers, perform at the required functions.
  • Various storage media may be fixed within a processor or controller or may be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Disinfection, Sterilisation Or Deodorisation Of Air (AREA)
  • Ventilation (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

L'invention concerne un système de filtration (10) destiné à retirer un polluant gazeux cible d'un gaz à filtrer dans un espace intérieur, le système de filtration (10) comprenant : un dispositif de capteur (12), qui comprend un capteur de gaz (14) destiné à détecter une concentration d'un gaz cible dans l'espace intérieur ; un épurateur d'air (20) qui comprend un filtre (22) destiné à filtrer le gaz cible du gaz à filtrer, et un système de ventilation (24) destiné à entraîner de manière contrôlée l'air à travers le filtre (22), le filtre (22) comprenant un filtre d'absorption réversible ou un filtre d'adsorption réversible ; et un dispositif de commande (26) destiné à commander les paramètres de flux d'air du système de ventilation, le dispositif de commande (26) étant conçu, sur la base des signaux actuels du dispositif de capteur et d'un historique précédent des signaux du dispositif de capteur et des réglages précédents de flux d'air du système de ventilation, pour : déterminer un degré de chargement du filtre (22) avec le gaz cible ; déterminer à partir du degré de chargement du filtre (22) avec le gaz cible une concentration du gaz cible dans le flux d'air quittant l'épurateur d'air (20) ; et déterminer quand une régénération du filtre (22) a lieu et quand une filtration d'air a lieu à partir de la concentration déterminée du gaz cible dans le flux d'air quittant l'épurateur d'air (20). L'invention concerne en outre un procédé de commande d'un système de filtration destiné à retirer un polluant gazeux cible d'un gaz à filtrer dans un espace intérieur.
EP16770469.1A 2015-09-17 2016-09-16 Système et procédé de filtration de gaz Withdrawn EP3349877A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP2015185612 2015-09-17
PCT/EP2016/071955 WO2017046321A1 (fr) 2015-09-17 2016-09-16 Système et procédé de filtration de gaz

Publications (1)

Publication Number Publication Date
EP3349877A1 true EP3349877A1 (fr) 2018-07-25

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