CN205067439U - VOCs concentration on -line monitoring device - Google Patents
VOCs concentration on -line monitoring device Download PDFInfo
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- CN205067439U CN205067439U CN201520712031.XU CN201520712031U CN205067439U CN 205067439 U CN205067439 U CN 205067439U CN 201520712031 U CN201520712031 U CN 201520712031U CN 205067439 U CN205067439 U CN 205067439U
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Abstract
The utility model relates to a VOCs concentration on -line monitoring device, including gas sampling unit, gas analysis unit, VOCs real -time detection unit and control and data processing unit, its innovation point lies in: the gas sampling unit includes the sampling pipe, the gas analysis unit is written into the subassembly including deciding buret, first control valve, gas chromatograph and carrier gas, the sampling pipe, decide buret, gas chromatograph and carrier gas and be written into the subassembly and put through mutually with the first control valve respectively, the VOCs real -time detection unit includes second control valve and gas detector, the second control valve is put through with gas detector mutually, control is the industrial computer with the data processing unit, gas chromatograph, gas detector, first control valve, second control valve and carrier gas be written into the subassembly respectively with industrial computer electrical connection. The utility model has the advantages of to the mist of the unknown, carry out gaseous composition analysis, ration calculation and real -time on -line monitoring.
Description
Technical field
The utility model relates to a kind of on-Line Monitor Device, is specifically related to a kind of VOCs concentration on-line monitoring device.
Background technology
VOCs is the english abbreviation of volatile organic matter (VolatileOrganicCompounds), according to the World Health Organization (WHO) (WTO) to its definition, refer to that boiling point, at 50 DEG C ~ 260 DEG C, and is the type organic be present in vapour form in air to fusing point at normal temperatures lower than room temperature.
VOCs comprises alkanes, arene, esters of gallic acid, aldehydes etc., anthropogenic discharge is mainly derived from the partial combustion process in productive life and relates to the industrial circle of organic products volatilization loss process, such as petrochemical industry, coatings for furniture industry, printing and dyeing industry etc.The main harm that VOCs causes is mainly manifested in three aspects: part has toxicity and carcinogenicity, can jeopardize the health of human body, such as benzene, toluene, formaldehyde, can cause very major injury to human body; Participation photo-chemical smog reacts, and forms ozone, Peroxyacetyl nitrate etc.; Participate in the formation of secondary particulate in air, closely related with the concentration abnormality of PM2.5.Therefore, administer and monitor very important to the VOCs discharge in commercial production.
Two kinds are mainly contained at present: hydrogen flameionization detector (flameionizationdetector, FID) and photoionization detector (PhotoionizationDetector, PID) for the detecting device detected VOCs concentration.Hydrogen flameionization detector FID is that the flame that generates with hydrogen and air burning is for the energy, when organic gas enters hydrogen flame, at high temperature produce chemi-ionization, all response is had to nearly all volatile organic compound, almost equal to the relative response of all hydrocarbon compounds (carbon number >=3).Photoionization detector PID is bombarded gas molecule in ionization chamber by the ultraviolet light with particular radiation energy (as 10.6eV), the organic gas contained in gas is ionized into the ion of positively charged and electronegative electronics, electric current is formed under electric field action, outputed signal after method, the field such as its production and transport at inflammable and explosive material, chemical material leakage, environmental emergency accident, trace measurement is widely used.In gas analysis field, gas chromatograph (GasChromatography, GC) is conventional analytical instrument, each component of mixed gas can be carried out being separated, measuring.VOCs detecting device, in conjunction with vapor-phase chromatography, as the detecting device of gas chromatograph, can carry out qualitative and quantitative analysis to mixed gas VOCs.
An important parameter of photoionization detector PID is correction coefficient CF, also known as response coefficient RF.Gas with various has different correction coefficient CF, and characterize the sensitivity that photoionization detector PID measures specific gas, CF value is lower, and sensitivity is higher.The CF value difference of different VOCs gas is larger, therefore photoionization detector PID is difficult to accurate quantitative analysis when measuring the gas of unknown component, in addition for the VOCs gas that some ionization potential is higher, the ultraviolet light of conventional 10.6eV cannot make it ionize, and need use high-octane uviol lamp.And hydrogen flameionization detector FID is typical mass flow rate sensitive detector, to almost all organism all can to respond and response coefficient is more stable, the total organic carbon amount (TOC) or the total hydrocarbon amount (THC) that quantitatively detect gas have good effect.Photoionization detector FID direct-reading method and gas chromatography-hydrogen flameionization detector (gaschromatography-flameionizationdetection is mainly contained at present for the method for VOCs being carried out to quantitative measurment, GC-FID) method, hydrogen flameionization detector FID direct-reading method is for measuring total hydrocarbon amount, and gas chromatography-hydrogen flameionization detector GC-FID method is except can obtaining VOCs total amount, also quantitative measurment can be carried out to wherein specific component.Owing to needing to consume the gases such as hydrogen in hydrogen flameionization detector FID use procedure, it will be too frequent that continuous use gas cylinder is changed, when carrying out gas chromatographic analysis simultaneously, need to carry out enrichment to meet the requirement of measurement sensistivity, current hydrogen flameionization detector FID or gas chromatography-hydrogen flameionization detector GC-FID is mainly used in offline inspection, online gas chromatography-photoionization detector (gaschromatography-PhotoionizationDetector, GC-PID) GC-PID monitoring system also only can periodic sampling, but can not Real-Time Monitoring.
Photoionization detector PID is compared with hydrogen flameionization detector FID, and it is lightweight, volume is little, highly sensitive, fast response time, does not simultaneously need carrier gas or combustion gas, long service life and essential safety, is applicable to carry out real time on-line monitoring.And gas chromatography-photoionization detector GC-PID and gas chromatography-hydrogen flameionization detector GC-FID is similar, also can carry out VOCs total amount to measure and specific components content measurement, but its gaseous sample does not need through enrichment, can direct injected, decrease the error introduced in pre-concentration process.Though real-time detection can be realized using photoionization detector PID as the on-line monitoring system of detecting device, and for the pure gas of Known Species or the mixed gas of known component and ratio thereof, the testing result of photoionization detector PID can calculate the content of VOCs total amount accurately and wherein a certain or a certain class gas.But for the gas of component the unknown, the testing result of photoionization detector PID can only provide the total amount of VOCs roughly to be estimated, can not detect by accurate quantitative analysis.
At present, for the mixed gas of unknown component, especially switch the application scenario changed with production technology in component, good solution be there is no to the real time on-line monitoring of VOCs and quantitative test.
Summary of the invention
The purpose of this utility model is: provide a kind of mixed gas for unknown component, can carry out the VOCs concentration on-line monitoring device of Analysis On Gaseous Constituents, quantitatively calculating and real time on-line monitoring, to overcome the deficiencies in the prior art.
In order to achieve the above object, the technical solution of the utility model is: a kind of VOCs concentration on-line monitoring device, and comprise gas sampling cell, gas analysis unit, the real-time detecting unit of VOCs and control and data processing unit, its innovative point is:
Described gas sampling cell comprises sampling pipe;
Described gas analysis unit comprises quantity tube, the first operation valve, gas chromatograph and carrier gas and is loaded into assembly, and described sampling pipe, quantity tube, gas chromatograph and carrier gas are loaded into assembly and are connected with the first operation valve respectively;
The real-time detecting unit of described VOCs comprises the second operation valve and detector, and described second operation valve and detector are connected;
Described control and data processing unit are industrial computers, and described gas chromatograph, detector, the first operation valve, the second operation valve and carrier gas are loaded into assembly and are electrically connected with industrial computer respectively.
In technique scheme, described gas sampling cell also comprises gas treatment equipment and T-valve, and sampling pipe is connected by gas treatment equipment and T-valve; Described gas treatment equipment has two kinds of frame modes, a kind of mode comprises split type and the moisture separator connected by pipeline and clarifier, sampling pipe and moisture separator are connected, first valve port of clarifier and T-valve is connected, another kind of mode is the clarifier that dries of integrated form, and sampling pipe is connected by the first valve port of dry clarifier and T-valve.
In technique scheme, one end mouth of pipe of described quantity tube and the first valve port of the first operation valve are connected, and the 4th valve port of the other end mouth of pipe of quantity tube and the first operation valve is connected, second valve port of the first operation valve and the import of gas chromatograph are connected, the outlet that 3rd valve port of the first operation valve and carrier gas are loaded into assembly is connected, 5th valve port of the first operation valve and the second valve port of T-valve are connected, 6th valve port of the first operation valve and the air intake opening of asepwirator pump are connected, and the exhausr port of asepwirator pump is connected with air.
In technique scheme, described carrier gas is loaded into assembly and comprises the carrier gas tank, the first stop valve, the first reduction valve, first flow variable valve and the spinner-type flowmeter that are connected successively, the outlet of described spinner-type flowmeter is the outlet that carrier gas is loaded into assembly, and the 3rd valve port of the outlet of spinner-type flowmeter and the first operation valve is connected.
In technique scheme, the real-time detecting unit of described VOCs also comprises detector periodic calibrating assembly, first valve port of described second operation valve and the 3rd valve port of T-valve are connected, second valve port of the second operation valve and the import of detector are connected, and the 3rd valve port of the second operation valve and the outlet of detector periodic calibrating assembly are connected.
In technique scheme, described detector periodic calibrating assembly comprises air bottle at zero point, standard gas distributing bottle, second stop valve, 3rd stop valve, second reduction valve and second adjustable valve, described zero point, air bottle was connected by the import of the second stop valve and the second reduction valve, standard gas distributing bottle is connected by the import of the 3rd stop valve and the second reduction valve, the outlet of the second reduction valve and the import of second adjustable valve are connected, the outlet of second adjustable valve is the outlet of detector periodic calibrating assembly, and the outlet of second adjustable valve is connected with the 3rd valve port of the second operation valve.
In technique scheme, described control and data processing unit are the industrial computers with man-machine interface, and described gas chromatograph and detector are electrically connected respectively by RS485 or RS232 and control and data processing unit.
In technique scheme, what store in described carrier gas tank is purify air or nitrogen.
The good effect that the utility model has is: the utility model comprises gas sampling cell, gas analysis unit, the real-time detecting unit of VOCs and control and data processing unit; Described gas sampling cell comprises sampling pipe; Described gas analysis unit comprises quantity tube, the first operation valve, gas chromatograph and carrier gas and is loaded into assembly, and described sampling pipe, quantity tube, gas chromatograph and carrier gas are loaded into assembly and connect with the first operation valve respectively; The real-time detecting unit of described VOCs comprises the second operation valve and detector, and described second operation valve and detector are connected; Described control and data processing unit are industrial computers, and described gas chromatograph, detector, the first operation valve, the second operation valve and carrier gas are loaded into assembly and are electrically connected with industrial computer respectively; Wherein, the gas chromatograph of gas analysis unit is used for analyzing the component of the gas to be measured in the quantity tube of quantitative sampling and ratio; The detector of the real-time detecting unit of VOCs can carry out in real time gas to be measured, continuous print is measured, and the gas composition obtained according to chromatographic and ratio thereof, can carry out quantitative accurately to the real-time testing result of detector.The utility model can carry out real time on-line monitoring to the VOCs concentration of industrial discharge, qualitative and quantitative analysis can be carried out to the composition of the gas to be measured of unknown component, not only can detect VOCs total amount, and the content of wherein specifically a certain or a certain class component can be obtained, and realize the object of real time on-line monitoring.
Accompanying drawing explanation
Fig. 1 is the on-Line Monitor Device schematic diagram of the first VOCs concentration of the utility model;
Fig. 2 is the on-Line Monitor Device schematic diagram of the utility model the second VOCs concentration
Fig. 3 is that quantity tube determines volume sampling process structural representation;
Fig. 4 is gas chromatography-photoionization detector GC-PID gas analysis procedure structure schematic diagram;
Fig. 5 is photoionization detector PID Real-Time Monitoring procedure structure schematic diagram;
Fig. 6 is photoionization detector PID periodic calibration procedure structure schematic diagram.
Embodiment
Below in conjunction with accompanying drawing and the embodiment that provides, the utility model is further described, but is not limited thereto.
As shown in Fig. 1,2,3,4,5,6, a kind of VOCs concentration on-line monitoring device, comprises gas sampling cell 1, gas analysis unit 2, the real-time detecting unit 3 of VOCs and controls and data processing unit 4,
Described gas sampling cell 1 comprises sampling pipe 1-1;
Described gas analysis unit 2 comprises quantity tube 2-1, the first operation valve 2-2, gas chromatograph 2-3 and carrier gas and is loaded into assembly 2-4, and described sampling pipe 1-1, quantity tube 2-1, gas chromatograph 2-3 and carrier gas are loaded into assembly 2-4 and are connected with the first operation valve 2-2 respectively;
The real-time detecting unit 3 of described VOCs comprises the second operation valve 3-1 and detector 3-2, and described second operation valve 3-1 and detector 3-2 is connected;
Described control and data processing unit 4 are industrial computers, and described gas chromatograph 2-3, detector 3-2, the first operation valve 2-2, the second operation valve 3-1 and carrier gas are loaded into assembly 2-4 and are electrically connected with industrial computer respectively.
As shown in Fig. 2,3,4,5,6, described gas sampling cell 1 also comprises gas treatment equipment and T-valve 1-4, and sampling pipe 1-1 is connected by gas treatment equipment and T-valve 1-4; Described gas treatment equipment has two kinds of frame modes, a kind of mode comprises the split type and moisture separator 1-2 connected by pipeline and clarifier 1-3, sampling pipe 1-1 and moisture separator 1-2 is connected, the first valve port 4a of clarifier 1-3 and T-valve 1-4 is connected, another kind of mode is the clarifier that dries of integrated form, and sampling pipe 1-1 is connected by the first valve port 4a of dry clarifier and T-valve 1-4.The moisture separator 1-2 of described gas sampling cell 1 is gas-liquid separator, and described clarifier 1-3 is soot dust granule filtrator.
The entrance of described T-valve 1-4 is pretreated gas to be measured, exports and is connected by controlling to carry out the real-time detecting unit 3 of switching and gas analysis unit 2 or VOCs with data processing unit 4.
As Fig. 3, 4, 5, shown in 6, for the ease of quantitative sampling, one end mouth of pipe of described quantity tube 2-1 and the first valve port 2a of the first operation valve 2-2 are connected, and the 4th valve port 2d of the other end mouth of pipe of quantity tube 2-1 and the first operation valve 2-2 is connected, the second valve port 2b of the first operation valve 2-2 and the import of gas chromatograph 2-3 are connected, the outlet that the 3rd valve port 2c of the first operation valve 2-2 and carrier gas are loaded into assembly 2-4 is connected, the 5th valve port 2e of the first operation valve 2-2 and the second valve port 4b of T-valve 1-4 is connected, the 6th valve port 2f of the first operation valve 2-2 and the air intake opening 5-2 of asepwirator pump 5 is connected, the exhausr port 5-1 of asepwirator pump 5 is connected with air.
As shown in Fig. 3,4,5,6, for the ease of being loaded into gas to be measured, described carrier gas be loaded into assembly 2-4 comprise be connected successively carrier gas tank 2-4-1, the first stop valve 2-4-2, the first reduction valve 2-4-3, first flow variable valve 2-4-4 and spinner-type flowmeter 2-4-5, the outlet of described spinner-type flowmeter 2-4-5 is the outlet that carrier gas is loaded into assembly 2-4, and the 3rd valve port 2c of the outlet of spinner-type flowmeter 2-4-5 and the first operation valve 2-2 is connected.
As shown in Fig. 3,4,5,6, the real-time detecting unit 3 of described VOCs also comprises detector periodic calibrating assembly 3-3, the first valve port 1a of described second operation valve 3-1 and the 3rd valve port 4c of T-valve 1-4 is connected, the second valve port 1b of the second operation valve 3-1 and the import of detector 3-2 are connected, and the 3rd valve port 1c of the second operation valve 3-1 and the outlet of detector periodic calibrating assembly 3-3 are connected.
As shown in Figure 6, in order to ensure the accuracy of detection of detector, need to detector periodic calibrating, described detector periodic calibrating assembly 3-3 comprises air bottle 3-3-1 at zero point, standard gas distributing bottle 3-3-2, second stop valve 3-3-3, 3rd stop valve 3-3-4, second reduction valve 3-3-5 and second adjustable valve 3-3-6, described zero point, air bottle 3-3-1 was connected by the import of the second stop valve 3-3-3 and the second reduction valve 3-3-5, standard gas distributing bottle 3-3-2 is connected by the import of the 3rd stop valve 3-3-4 and the second reduction valve 3-3-5, the outlet of the second reduction valve 3-3-5 and the import of second adjustable valve 3-3-6 are connected, the outlet of second adjustable valve 3-3-6 is the outlet of detector periodic calibrating assembly 3-3, and the outlet of second adjustable valve 3-3-6 is connected with the 3rd valve port 1c of the second operation valve 3-1.What store in described carrier gas tank 2-4-1 is purify air or nitrogen.
The utility model is for the ease of communication, and described control and data processing unit 4 are the industrial computers with man-machine interface, and described gas chromatograph 2-3 and detector 3-2 is electrically connected respectively by RS485 or RS232 and control and data processing unit 4.
Gas chromatograph 2-3 of the present utility model can select the gas chromatography-hydrogen flameionization detector GC-FID using hydrogen flameionization detector FID as detecting device, also the gas chromatography using photoionization detector PID as detecting device-photoionization detector GC-PID(can be selected preferentially to select this kind, the product G CRAE1000 of Hua Rui group of the U.S. can be selected); Detector 3-2 can select photoionization detector PID(preferentially to select this kind, the product RAEGuard2 of Hua Rui group of the U.S. can be selected), also Pulsed Discharge Helium ionized gas detecting device PDHID (pulseddischargeheliumionizationdetector, PDHID) can be selected.
Utility model works process: the utility model is when technique starts, first quantity tube is utilized to sample air flue emission gasometry, then the gaseous sample in quantity tube is loaded into gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID by carrier gas) in, carry out component and concentration analysis, testing result is transferred to by RS485 communication mode and controls and data processing unit 4, after stratographic analysis completes, the air flue emission gas of sampling sends into Real-Time Monitoring detector 3-2(photoionization detector PID) in detect, analysis is carried out quantitative according to stratographic analysis result, control the final concentration of emission in real time obtaining VOCs with data processing unit 4.Except technique start time, in production, process, also gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID can regularly be utilized) again the component of emission gases, ratio are analyzed, analysis result when starting with technique is compared and is corrected, and by recalibrating, revised gas composition and proportion grading result be used for detector 3-2(photoionization detector PID) quantitative test of testing result in real time.
Below the concrete enforcement of each step is described:
Step a, gas sample;
Described gas sample step is sampled the mixed gas to be measured of air flue emission by the sampling pipe 1-1 of gas sampling cell 1;
The utility model sampling pipe 1-1 adopts Teflon material (PTFE), and it has heat-resisting quantity, moisture resistance, the feature of anti-organic solvent, can not impact VOCs to be measured.Gas-liquid separator is for separating of the steam contained in gas to be measured, avoid fluent meterial to enter detecting device and cause measuring error or instrument damage, smoke filter avoids the gas circuit of checkout equipment to shorten life-span or damage because of blocking for separating of the solid particulate matter composition in gas to be measured.
Step b, gas composition are separated and Concentration Testing;
Described gas composition separation is by the quantity tube 2-1 of the gaseous sample insufflation gas analytic unit 2 in sampling pipe 1-1 in step a with concentration detecting step and carries out quantitative sampling, then assembly 2-4 is loaded into by advanced promoting the circulation of qi body Component seperation in the gas chromatograph 2-3 of the gas loading gas analysis unit 2 in quantity tube 2-1 by the carrier gas of gas analysis unit 2, the ratio A shared by the component N of the mixed gas in quantity tube 2-1 and each component is determined by gas chromatograph 2-3, and this analysis result is delivered to control with in data processing unit 4, then by controlling with data processing unit 4 according to following formula, ask for the average correction coefficient CF of mixed gas
ɑ v value and average molar mass M
ɑ v ,
Wherein, A
ithe ratio that i-th kind of gas is corresponding,
CF
ithe correction coefficient that i-th kind of gas is corresponding,
M
iit is the molal weight that i-th kind of gas is corresponding;
Due to detector 3-2(photoionization detector PID) detection sensitivity is high, can detect and be low to moderate 10ppb or the lower gas componant of content, therefore gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) gaseous sample do not need through adsorption tube enrichment-Thermal desorption step, the utility model selects the mode of quantity tube quantitative sampling, gather gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) analysis gaseous sample, general quantity tube volume is 1 ~ 5mL, as far as possible little when meeting sensitivity measure demand.
The utility model the gas circuit of quantitative sampling process connect with the position of solenoid valve as shown in Figure 3.The gas of air flue emission is through sampled point, carried by Teflon (PTFE) sampling pipe 1-1, after completing by steam trap, smoke filter the particle-removing thing that dewaters, by asepwirator pump 5, gas to be measured is sucked quantity tube through T-valve 1-4 and the first operation valve 2-2, now, one end mouth of pipe of quantity tube 2-1 is by the entrance of the first operation valve 2-2 as the gas to be measured after purification, the other end mouth of pipe is then as the outlet of gas to be measured, air is disposed to via asepwirator pump 5, after this step completes, be the gaseous sample of unit volume in quantity tube.
Gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) Component seperation be connected with the gas circuit of Concentration Testing process with solenoid valve position as shown in Figure 5.By step 1) to step 2) transition need the spool position of switching first operation valve 2-2, now, one end mouth of pipe of quantity tube 2-1 is connected with the gas vent that carrier gas is loaded into assembly 2-4 by the first operation valve 2-2, the other end mouth of pipe and gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) gas access be connected, open the first stop valve 2-4-2, it is through the first reduction valve 2-4-3, first flow variable valve 2-4-4, after spinner-type flowmeter 2-4-5, carrier gas enters quantity tube 2-1, the sample gas promoted in quantity tube 2-1 with certain flow velocity is loaded into gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) chromatographic column in, through chromatographic column be separated after be loaded into gas chromatograph 2-3(gas chromatography-photoionization detector GC-PID) in detector 3-2(photoionization detector PID) detect.Because detector 3-2 is provided as photoionization detector PID, carrier gas can use pure air or nitrogen.After stratographic analysis completes, close the first stop valve 2-4-2.
Step c, VOCs on-line real-time measuremen;
Described VOCs on-line real-time measuremen step detects in the detector 3-2 of the real-time real-time detecting unit 3 of VOCs detected of mixed gas feeding to be measured of air flue emission, the correction coefficient CF value of described detector 3-2 is set to 1, then by the volumetric concentration C by detector 3-2 real-time detecting mixing gas
1deliver to and control with in data processing unit 4;
The gas circuit connection of photoionization detector PID on-line real-time measuremen process and solenoid valve position are as shown in Figure 5.By step 2) to step 3) transition need the spool position of switch three-way valve 1-4, flue gas to be measured after purification is connected with the real-time detecting unit of VOCs based on photoionization detector PID by T-valve 1-4, by the second operation valve 3-1, flue gas to be measured but not demarcate gas enter photoionization detector PID, the correction coefficient CF value of photoionization detector PID is set to 1, the real-time testing result of photoionization detector PID is extremely controlled and data processing unit by RS485 communications.
The calculating of the real-time concentration of emission of steps d, VOCs exports;
It is by the average correction coefficient CF controlling to obtain according to step b with data processing unit (4) mixed gas that the calculating of the real-time concentration of emission of described VOCs exports step
avvalue and average molar mass M
av, and the volumetric concentration C of the mixed gas obtained according to step C
1, the real-time concentration of emission of analytical calculation VOCs:
The real-time emission gases volumetric concentration C of VOCs,
C=C
1×CF
ɑv （PPM）；
VOCs real-time emission gases mass volume ratio concentration X,
X=M
ɑv ×C/22.4（mg/m
3）；
The real-time emission gases volumetric concentration C of i-th kind of gas composition in VOCs
i,
C
i=C×A
i（ppm）；
I-th kind of gas composition real-time emission gases mass volume ratio concentration X in VOCs
i,
X
i=X×A
i(mg/m
3)。
Described control and data processing unit 4 are by industrial computer and related peripheral module composition, switch and the electrical control of equipment component for the solenoid valve in on-line monitoring and instrumental calibration process, and realization carries out data processing to the measurement result of gas analysis unit and the real-time detecting unit of VOCs.Its software comprises solenoid valve and actuating of relay logic control, gas chromatographic analysis, in real time testing result quantitative test three main modular, is furnished with human-computer interaction interface.The real-time testing result of photoionization detector PID is shown to user by the man-machine interface of industrial computer, and is exceeding effluent standard limit value alarm.
The embodiment that the photoionization detector PID that the utility model adopts detector 3-2 demarcates, and detailed process is:
Photoionization detector PID adopts 2 modes of demarcating to carry out instrument calibration, and namely Zero calibration and calibrating gas are demarcated.First, zero gas is used to demarcate zero point; Then, select the calibrating gas of concentration known to carry out calibrating gas demarcation, Zero calibration need carry out before calibrating gas is demarcated.Within general 3 ~ 6 months, once need demarcate photoionization detector PID, to ensure the accuracy measured.
To detector 3-2 adopt photoionization detector PID carry out timing signal, first by the gas circuit of system connect with solenoid valve position as shown in Figure 6.By the second operation valve 3-1 in Fig. 6, by zero point air or calibrating gas send into photoionization detector PID through the second reduction valve 3-3-5 and second adjustable valve 3-3-6, select the gas entering photoionization detector PID to be zero gas or gas by the opening and closing controlling the second stop valve 3-3-3 and the 3rd stop valve 3-3-4.
Carry out timing signal, first the second stop valve 3-3-3 of zero gas air bottle 3-3-1 is opened, operational light ionized gas detecting device PID carries out Zero calibration, after completing, close the second stop valve 3-3-3, then open the 3rd stop valve 3-3-4, operational light ionized gas detecting device PID Engage of standard gas calibration point is demarcated, after demarcation completes, closedown the 3rd stop valve 3-3-4, now completes the instrument calibration of a detector 3-2.
Photoionization detector (the PhotoionizationDetector that the utility model adopts, PID) based on photoionization technology, by the ultraviolet light with particular radiation energy (being generally 10.6eV), gas molecule is ionized into the ion of positively charged and electronegative electronics, positive ion and electronics move and form electric current under electric field action, amplify output current signal through transmitter.The gas that can be detected by photoionization detector PID, its ionization potential need lower than the energy of uviol lamp.Major part carbon containing class organic compound is as aromatics (benzene series), ketone, aldehydes, alcohols etc., and the inorganics such as ammonia, arsenic, selenium can be detected by photoionization detector PID, air, methane, common poison gas (CO, HCN, SO
2), nonvolatile gas etc. can not detect by photoionization detector PID.Photoionization detector PID fast response time, highly sensitive, be environmental protection, trace measurement and detect the powerful tool of the aspects such as pollution in real time.
An important parameter of photoionization detector PID is correction coefficient CF, and gas with various has different correction coefficient, and characterize the sensitivity that photoionization detector PID measures specific gas, CF value is lower, and sensitivity is higher.The instrument that calibrated gas (CF=1.00, conventional isobutylene) was calibrated, namely CF value measurement result being multiplied by corresponding gas to be measured obtains actual concentrations (correction coefficient also by arranging instrument obtains actual concentrations).For the pure gas of Known Species or the mixed gas of known component and ratio thereof, the content of VOCs total amount accurately and wherein a certain or a certain class gas can be calculated by the testing result of photoionization detector PID.And for the gas of component the unknown, the testing result of photoionization detector PID can only provide the total amount of VOCs roughly to be estimated, can not accurate quantitative analysis.
Photoionization detector PID and vapor-phase chromatography (GasChromatography, GC) are combined, is the gas chromatography-photoionization detector GC-PID measuring each gas composition and concentration thereof.Vapor-phase chromatography, is by the chromatography of gas as mobile phase.The chief component of gas chromatograph is that chromatographic column and detecting device are formed, after adding from chromatographic column one end for the sample be separated, analyze, different samples is because have different physics and chemistry character, there is different interactions from specific tubing string filling material (Stationary liquid) and driven with different speed by carrier gas, flow out from chromatographic column end through different retention times, detect its content by detecting device, produce corresponding signal, and be converted into electric signal output.The effect of Stationary liquid is separated different components in the chromatography column, and different components is flowed out from the end of post after different retention times.Other affects material and flows out the flow velocity that the order of post and the factor of retention time comprise carrier gas, temperature etc.Thus, utilize gas chromatograph, qualitative and quantitative analysis can be carried out to gas composition and concentration.Highly sensitive due to photoionization detector PID, the VOCs gas of extremely low concentration can be detected, therefore GC-FID is different from gas chromatography-hydrogen flameionization detector, does not need to carry out enrichment (pre-concentration) to gas to be measured using photoionization detector PID as the gas chromatography of detecting device-photoionization detector GC-PID.But gas chromatograph is used for off-line analysis, instead of on-line monitoring, its analytical cycle is relatively long simultaneously, cannot realize the Real-Time Monitoring to industrial discharge.
In sum, the utility model has following feature:
1) a kind of method gas chromatograph component analysis and on-line checkingi device being detected fast combination is proposed, gas chromatography is utilized to obtain component and the ratio of unknown mixed gas, for carrying out analyzing and processing to the measurement result of photoionization detector PID on-line checkingi device.Present method solves photoionization detector PID detecting device different to gas with various response, be difficult to the problem of accurate quantitative analysis, achieve and real-time, online quantitative detection is carried out to the mixed gas of unknown component, and mixed gas is without the need to enrichment, avoid the error introduced in pre-concentration process;
2) native system can not only provide the real-time online testing result of VOCs total amount, also can provide the content of wherein specifically a certain or a certain class gas componant;
3) high ionization current potential component is contained as formaldehyde for emission, the occasion of methylene chloride, photoionization detector PID in gas chromatography in native system-photoionization detector GC-PID adopts the uviol lamp of 11.7eV as light source, ensure that detectable gas covers nearly all VOCs, and the photoionization detector PID of on-line monitoring adopts the uviol lamp of 10.6eV, working stability, long service life, utilize it can respond the testing result of gas, in conjunction with the analysis result of gas chromatography-photoionization detector GC-PID, its content that can not respond gas and VOCs total amount can be provided,
4) combination of operation valve (six-way valve), T-valve, stop valve is utilized, achieve quantity tube sampling, gas chromatography-photoionization detector GC-PID gas chromatographic analysis, photoionization detector PID on-line real time monitoring, photoionization detector PID instrumental calibration four kinds of mode of operations automatic, switch fast, coordinate gas pre-service device and flow control device, define complete air-channel system, be convenient to automatically control;
5) method that proposed component analysis is combined with on-line checkingi is not only confined to photoionization detector PID or gas chromatography-photoionization detector GC-PID, in different application scenarios, according to different object gas and the requirement to measurement sensistivity, the photoionization detector PID that other detecting devices can be selected to substitute the photoionization detector PID in gas chromatograph and detect in real time, realizes the real time on-line monitoring to mixed gas.
For different application scenarios, different gas to be measured and concentration, based on design proposal and the basic boom of native system, select corresponding detecting device, such as the detecting device of the detecting device of gas chromatograph and detection is in real time replaced by electron capture detector (ECD) ECD, flame ionization ditector FID etc., the gas of the different kind that can meet the different needs, measure.The method that native system provides is applicable to the on-line real time monitoring to unknown mixed gas, and is not only confined to photoionization detector PID.
Claims (8)
1. a VOCs concentration on-line monitoring device, comprises gas sampling cell (1), gas analysis unit (2), the real-time detecting unit of VOCs (3) and controls and data processing unit (4), it is characterized in that:
Described gas sampling cell (1) comprises sampling pipe (1-1);
Described gas analysis unit (2) comprises quantity tube (2-1), the first operation valve (2-2), gas chromatograph (2-3) and carrier gas and is loaded into assembly (2-4), and described sampling pipe (1-1), quantity tube (2-1), gas chromatograph (2-3) and carrier gas are loaded into assembly (2-4) and are connected with the first operation valve (2-2) respectively;
The real-time detecting unit of described VOCs (3) comprises the second operation valve (3-1) and detector (3-2), and described second operation valve (3-1) and detector (3-2) are connected;
Described control and data processing unit (4) are industrial computers, and described gas chromatograph (2-3), detector (3-2), the first operation valve (2-2), the second operation valve (3-1) and carrier gas are loaded into assembly (2-4) and are electrically connected with industrial computer respectively.
2. VOCs concentration on-line monitoring device according to claim 1, it is characterized in that: described gas sampling cell (1) also comprises gas treatment equipment and T-valve (1-4), sampling pipe (1-1) is connected by gas treatment equipment and T-valve (1-4); Described gas treatment equipment has two kinds of frame modes, a kind of mode comprises split type and the moisture separator (1-2) connected by pipeline and clarifier (1-3), sampling pipe (1-1) and moisture separator (1-2) are connected, clarifier (1-3) is connected with first valve port (4a) of T-valve (1-4), another kind of mode is the clarifier that dries of integrated form, and sampling pipe (1-1) is connected by first valve port (4a) of dry clarifier and T-valve (1-4).
3. VOCs concentration on-line monitoring device according to claim 2, it is characterized in that: one end mouth of pipe of described quantity tube (2-1) and first valve port (2a) of the first operation valve (2-2) are connected, and the 4th valve port (2d) of the other end mouth of pipe of quantity tube (2-1) and the first operation valve (2-2) is connected, second valve port (2b) of the first operation valve (2-2) and the import of gas chromatograph (2-3) are connected, the outlet that 3rd valve port (2c) of the first operation valve (2-2) and carrier gas are loaded into assembly (2-4) is connected, 5th valve port (2e) of the first operation valve (2-2) and second valve port (4b) of T-valve (1-4) are connected, 6th valve port (2f) of the first operation valve (2-2) and the air intake opening (5-2) of asepwirator pump (5) are connected, the exhausr port (5-1) of asepwirator pump (5) is connected with air.
4. VOCs concentration on-line monitoring device according to claim 1, it is characterized in that: described carrier gas is loaded into assembly (2-4) and comprises the carrier gas tank (2-4-1), the first stop valve (2-4-2), the first reduction valve (2-4-3), first flow variable valve (2-4-4) and the spinner-type flowmeter (2-4-5) that are connected successively, the outlet of described spinner-type flowmeter (2-4-5) is the outlet that carrier gas is loaded into assembly (2-4), and the 3rd valve port (2c) of the outlet of spinner-type flowmeter (2-4-5) and the first operation valve (2-2) is connected.
5. VOCs concentration on-line monitoring device according to claim 2, it is characterized in that: the real-time detecting unit of described VOCs (3) also comprises detector periodic calibrating assembly (3-3), first valve port (1a) of described second operation valve (3-1) and the 3rd valve port (4c) of T-valve (1-4) are connected, second valve port (1b) of the second operation valve (3-1) and the import of detector (3-2) are connected, and the 3rd valve port (1c) of the second operation valve (3-1) and the outlet of detector periodic calibrating assembly (3-3) are connected.
6. VOCs concentration on-line monitoring device according to claim 5, it is characterized in that: described detector periodic calibrating assembly (3-3) comprises air bottle at zero point (3-3-1), standard gas distributing bottle (3-3-2), second stop valve (3-3-3), 3rd stop valve (3-3-4), second reduction valve (3-3-5) and second adjustable valve (3-3-6), described air bottle at zero point (3-3-1) is connected by the import of the second stop valve (3-3-3) with the second reduction valve (3-3-5), standard gas distributing bottle (3-3-2) is connected by the import of the 3rd stop valve (3-3-4) with the second reduction valve (3-3-5), the outlet of the second reduction valve (3-3-5) and the import of second adjustable valve (3-3-6) are connected, the outlet of second adjustable valve (3-3-6) is the outlet of detector periodic calibrating assembly (3-3), and the outlet of second adjustable valve (3-3-6) is connected with the 3rd valve port (1c) of the second operation valve (3-1).
7. VOCs concentration on-line monitoring device according to claim 1, it is characterized in that: described control and data processing unit (4) are the industrial computers with man-machine interface, described gas chromatograph (2-3) and detector (3-2) are electrically connected respectively by RS485 or RS232 and control and data processing unit (4).
8. VOCs concentration on-line monitoring device according to claim 4, is characterized in that: what store in described carrier gas tank (2-4-1) is purify air or nitrogen.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105136958A (en) * | 2015-09-15 | 2015-12-09 | 顾金华 | VOC (Volatile Organic Compound) concentration online monitoring device |
| CN108007699A (en) * | 2017-12-28 | 2018-05-08 | 清华大学 | A kind of modular pollutant of vehicle exhaust on-board emission test platform |
| CN108007699B (en) * | 2017-12-28 | 2023-09-29 | 清华大学 | Modularized vehicle-mounted emission test platform for tail gas pollutants of motor vehicle |
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| WO2023050825A1 (en) * | 2021-09-30 | 2023-04-06 | 深圳市普瑞美泰环保科技有限公司 | Vocs concentration measurement method and device, and readable storage medium |
| CN114252496A (en) * | 2022-03-01 | 2022-03-29 | 河北沃茵环保科技有限公司 | VOCs online automatic monitoring system |
| CN114252496B (en) * | 2022-03-01 | 2022-05-17 | 河北沃茵环保科技有限公司 | VOCs online automatic monitoring system |
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