• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Process and apparatus for the determination of the total organic substance content of gases by a flame ionization detector, respectively comprising the steps and means for allowing components of the gas to be analyzed to diffuse through a pore-free polymeric membrane having a permeability coefficient that exceeds 10-7 Ncm3.cm/sec.cm2.Hgcm. related to the total organic substance contained in the gas, leading the gas components into a flame of another gas that contains hydrogen, passing the burning hydrogen-containing gas along one side of the membrane at a flow rate of max. 25 cm3/min., simultaneously pumping the gas to be analyzed on the other side of the membrane at a volumetric flow of at least tenfold of that of the other gas, diffusing the organic substances to be determined through the membrane, subsequently leading the organic substances that have diffused through the membrane, in admixture with the other gas, into the flame ionization detector, and determining the total organic substances therein.
    公开号:SU890993A3
    申请号:SU772557601
    申请日:1977-12-22
    公开日:1981-12-15
    发明作者:Ностициуш Золтан；Олах Карой；Патонаи Габор；Лангер Карой；Соммер Ференц；Гашпар Дьюла；Палмай Дьердь；Секей Дьердь；Вайта Жофиа
    申请人:Чепел Мювек Хира Даштехникаи Гелдьяра (Инопредприятие)；
    IPC主号:
    专利说明:

    Determine hydrocarbons in the entire concentration range from O to 100. Another disadvantage of instruments operating on the principle of flame ionization detection is that they are also sensitive to the flow rate of the gas sample. The closest to the technical essence of the invention is a method for determining the content of organic substances in gases using a flame ionization detector, including supplying a chamber with a membrane permeable to the components to be detected by the membrane of the analyzed mixture and supplying, together with a combustible gas, the components diffused through the membrane to the detector 2. It is necessary to create a measuring device insensitive to the flow rate of the sample, if the component to be detected is brought to the detector due to its diffusion through emfranu. At the same time, the test gas is passed through an infrared, calorimetric or other analyzer on one side of the membrane, passing only the component to be detected, while on the other side of the membrane a carrier gas flowing at a constant rate is passed. This device eliminates the ingress of water vapor and solid particles into the detector, as well as other interfering components. At the same time, by selecting the appropriate membrane, it is possible to create the conditions under which only the following component will get into the carrier gas. Maintaining a constant temperature in the cell in which the membrane is located provides the conditions under which the concentration of the component to be determined in the carrier gas is proportional to its concentration in the gas being analyzed. In this way, a dilution is created in which, for example, the content of the component to be detected in the clean air used as the carrier gas is proportional to its content in the flue gases. When determining organic substances using a flame ionization detector, this method cannot be used, since it does not give the possibility of determining the total amount of organic substances in the gas sample, which was proportional to the number of carbon atoms. Another disadvantage of this method is that the system works stably only if the permeability of the membrane is constant, and any factor that changes its permeability interferes. For this reason, the membrane must be thermostatically controlled, and must be replaced in the face of contamination or aging. In such cases, the measuring system needs to be re-calibrated. In addition, the membrane used has a different permeability with respect to various organic substances. In the case of a cumulative definition of several components, this means that the proportionality factor for the individual components, despite the fact that the amounts of the determined components in the carrier gas and will be proportional to their content in the analyzed gas, will be excellent and, therefore, the ratio of components in the carrier gas will differ from their ratio in the analyzed gas. The aim of the invention is to develop a method in which the advantages of infrared and flame ionization methods would be combined and with which it would be possible to determine with high sensitivity the content of organic substances in gases in the concentration range from 0 to 100% by volume. It is necessary to determine the total content of organic substances in gases using a flame ionization detector in such a way that the ratio of organic substances in the combustible gas entering the detector corresponds to their initial ratio in the sample and that the signal generated in the detector does not depend on velocity fluctuations within the measurement error The purpose of the invention is to expand the measurement range of organic substances in gases. The goal is achieved in order. That the combustible gas is passed along the membrane at a speed not exceeding 25 cm / min, the analyzed mixture, passing through the discharge on the other side of the membrane, is passed at a volumetric rate exceeding the volumetric rate of combustible gas not less than 10 times, the membrane is used with an area the surface is not more than 10 cm-made of silicone rubber with a thickness of not more than 2 μm. It is preferable to supply no more than 1/10 of the combustible gas introduced into the detector to the membrane. Combustible gas is passed along the membrane at a constant rate. A device for carrying out the proposed method may consist of a source of combustible gas containing hydrogen, or a hydrogen generator, for example, an electrolytic hydrogen generator, a sampler for sampling gas, a pump for moving the analyzed gas, and a flame ionization detector. It should also include a diffusion chamber divided by the membrane into two parts, one part of this chamber should be connected to the sampler and divided into two parts by a non-porous polymer membrane with a permeability coefficient for all detectable organic substances above 10 cm / sec. - see mercury source, and another part of the diffusion chamber is connected to a source of combustible gas and a flame ionization detector. A characteristic feature of the invention is that when diffused through the membrane in the gas sample, detectable substances in the detector are supplied to the hydrogen being burned, the resulting signal is proportional to the partial pressure of the organic substances in the gas being analyzed and also when using the corresponding membrane and proper selection of the flow rate, measure e1 (e on both sides of the membrane the partial pressures of organic substances can be set to approximately the same Fig. 1 is a schematic diagram of a conventional flame ionization method; Fig. 2 is a conventional flame ionization detection scheme, another variant. 6 In a flame ionization detector (see Fig. 1), going out through a small the nozzle 1 hydrogen or combustible hydrogen-containing gas (a mixture of hydrogen or helium hydrogen) is burned in air L. The resulting flame 2 is located between two electrodes 3 (it is advisable that the nozzle itself be one of the electrodes). A constant voltage of 100–200 V is applied to the electrodes from the voltage source. The current flowing in the circuit is measured with a current-measuring device 5. In the case of pure hydrogen-gas and air, the current can be less than 1 pA. Hydrogen is supplied either from a cylinder or obtained from water by electrolysis. Clean air plays a smaller role. Normal air (room air) can usually be used. When injected into the flame of 2 organic substances of the analyzed gas, the current increases due to ionization (sensitivity is a few pA / ppm of organic matter). In the case of inorganic gases, ionization does not occur. A simpler detector design has been developed (see Fig. 2) in which hydrogen or a combustible gas containing hydrogen is not mixed in the pipeline with the analyzed gas G, and this latter is fed together with air L to the flame 2. Combustion occurs due to the oxygen of the analyzed gas, it is impossible to directly detect samples of gas that does not contain oxygen or that contains it in small quantities, such as exhaust gases. In addition, the sensitivity of the method as well as infrared is not proportional to the number of carbon atoms in the compound. Sensitivity per carbon atom for various hydrocarbons determined using infrared and flame ionization methods, the sensitivity of n-hexane was adopted at 100, is given in the table.
    thirty
    methane
    103
    propane
    450
    ten
    103
    120
    The measured signal in the case of applying the PID as shown in FIG. 1 within 5% is proportional to the number of carbon atoms in the compound, whereas with the other two methods significant deviations are observed. For determining the content of organic substances in gases containing various organic compounds, only the flame ionization detector according to the scheme in FIG. 1. A disadvantage of flame ionization detectors in comparison with NIA methods is, however, the dependence of the arising signal (current value) on the gas flow rate, which therefore needs to be stabilized. In this case, the gas sample entering the detector passes through the pump, which can lead to a change in the gas composition.
    For organic matter in a cell, the following material balance can be recorded: the flow of organic matter coming from the gas sample paBQH to the outgoing flow of organic matter (in the sample gas + in hydrogen).
    If there is no pore in the membrane, i.e. organic matter can pass through it only due to diffusion, then in steady state the flow of organic matter along with hydrogen is equal to the flow of organic matter diffusing through the membrane, which is proportional to the difference in the partial pressures of organic matter on both sides of the membranes, hence the partial pressure of organic substances in hydrogen, depending on the partial pressure of it in the gas sample can be expressed by the following formula:
    R. one
    890993
    8 Continuation of the table
     А-Р and k 1
    where a is the surface of the membrane, cm; E is the thickness of the membrane, cm; P - the so-called permeability coefficient,
    Sok7sm5.7sm pt7st7 Organic matter combined for couples - a membrane that shows how much of it organic matter diffuses for 1 s through the membrane with a surface 1 and a thickness of 1 cm at a difference of partial pressures of 1 tM mercury. Art.
    3ts, Od - volumetric sample rates
    g of hydrogen and gas, cm / sec, partial pressure of organic matter in gaseous hydrocarbon
    and in the gas sample in front of the membrane, cm Hg.
    R - gas constant -, T - absolute temperature. It follows from the equation that at given temperature and bulk velocity of hydrogen, the partial pressure of organic matter from the hydrogen side depends on the flow rate of the sample gas and the permeability coefficient of the membrane. If the permeability of the membrane is large for all the organic substances present in the gas sample (gt is significantly less than 1) and the volumetric rate of the gas sample is 10 times greater than
    0 is the volumetric rate of hydrogen, i.e. Zn / Ld 0.1, then the partial pressure of organic substances from hydrogen strontium was; em more than 90 their partial pressure in the gas sample, i.e. the partial pressures on both sides of the membrane are approximately equal (P x RD).
    权利要求:
    Claims (2)
    [1]
     1. Patterson O.S., Henein N.A. Enussions form Combustion Engines
    89099312
    and cheir Control Am. Arbor Science Pu. bD. Inc. Ann Arbor, 1972, 305.0.
    [2]
    2. Patent of England f, 144b637, cl. G 1 N, pub. 1975 (prototype)
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    同族专利:
    公开号 | 公开日
    YU306077A|1982-10-31|
    HU177965B|1982-02-28|
    DE2757699B2|1981-02-26|
    ATA741977A|1984-07-15|
    AT377365B|1985-03-11|
    PL111961B1|1980-09-30|
    DE2757699C3|1981-10-29|
    US4201550A|1980-05-06|
    YU39832B|1985-04-30|
    PL203194A1|1978-07-31|
    DD133718A5|1979-01-17|
    DE2757699A1|1978-07-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2991158A|1957-11-20|1961-07-04|Harley John|Apparatus for the analysis and/or detection of substances by gas chromatography|
    US3455092A|1965-12-06|1969-07-15|Varian Associates|Gas analyzer inlet system for gaseous state materials|
    US3398505A|1965-12-06|1968-08-27|Varian Associates|Dual stage membrane gas separators with variable conductance means for varying their throughput|
    GB1098533A|1966-12-19|1968-01-10|Shell Int Research|Improvements in or relating to apparatus for detecting hydrocarbons|
    US3545931A|1968-08-28|1970-12-08|Monsanto Co|Ammonia analysis system|
    US3674435A|1970-06-05|1972-07-04|Environment One Corp|Low concentration constituent of gaseous mixture selective converter and detector|
    US3762878A|1971-04-19|1973-10-02|Beckman Instruments Inc|Apparatus for analyzing ambient air|
    GB1446637A|1973-01-02|1976-08-18|Dnyasciences Corp|Gas testing apparatus and method|
    US3926561A|1974-05-13|1975-12-16|Meloy Lab|Gas analysis employing semi-permeable membrane|FR2443676B1|1978-12-06|1984-08-31|Yanagimoto Seisakusho Co Ltd|
    US4311669A|1980-08-21|1982-01-19|The Bendix Corporation|Membrane interface for ion mobility detector cells|
    US5255553A|1989-11-17|1993-10-26|Orbisphere Laboratories Neuchatel Sa|Method and apparatus for determining specific thermal conductivity parameters of gases|
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    AUPM707494A0|1994-07-26|1994-08-18|Crc For Waste Management And Pollution Control Limited|A method and apparatus for environmental monitoring of low concentration levels of organic compounds|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    HU76CE1114A|HU177965B|1976-12-23|1976-12-23|Method and apparatus for detecting total organic material content lf gases by means of flame ionization detector|
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