Carbon dioxide analyzer

The gas-polymer-matrix model for sorption and transport of gases in polymers is consistent with the physical evidence that 1) there is only one population of sorbed gas molecules in polymers at any pressure, 2) the physical properties of polymers are perturbed by the presence of sorbed gas, and 3) the perturbation of the polymer matrix arises from gas-polymer interactions. Rather than treating the gas and polymer separately, as in previous theories, the present model treats sorption and transport as occurring through a gas-polymer matrix whose properties change with composition. Simple expressions for sorption, diffusion, permeation and time lag are developed and used to analyze carbon dioxide sorption and transport in polycarbonate. 

The material to be analyzed is pyrolyzed in an inert gas at 1100°C in the presence of carbon the carbon monoxide formed, if any, is either analyzed directly by chromatography or analyzed as carbon dioxide after oxidation by CuO. The CO2 is detected by infra-red spectrometry or by gas phase chromatography. 

A flame-ionization, total hydrocarbon analyzer determines the THC, and the total carbon content is calculated as methane. Other methods include catalytic combustion to carbon dioxide, which may be deterrnined by a sensitive infrared detector of the nondispersive type. Hydrocarbons other than methane and acetylene are present only in minute quantities and generally are inert in most appHcations. 

Commercial Hquid sodium alumiaates are normally analyzed for total alumiaa and for sodium oxide by titration with ethylene diaminetetraacetic acid [60-00-4] (EDTA) or hydrochloric acid. Further analysis iacludes the determiaation of soluble alumiaa, soluble siHca, total iasoluble material, sodium oxide content, and carbon dioxide. Aluminum and sodium can also be determiaed by emission spectroscopy. The total iasoluble material is determiaed by weighing the ignited residue after extraction of the soluble material with sodium hydroxide. The sodium oxide content is determiaed ia a flame photometer by comparison to proper standards. Carbon dioxide is usually determiaed by the amount evolved, as ia the Underwood method. 

A variety of instmments are available to analyze carbon monoxide in gas streams from 1 ppm to 90%. One group of analyzers determines the concentration of carbon monoxide by measuring the intensity of its infrared stretching frequency at 2143 cm . Another group measures the oxidation of carbon monoxide to carbon dioxide electrochemically. Such instmments are generally lightweight and weU suited to appHcations requiring portable analyzers. Many analyzers are equipped with alarms and serve as work area monitors. 

Molecular Weight EPA Method 3 is used to determine carbon dioxide and oxygen concentrations and dry molecular weight of the stack-gas stream. Depending on the intended use of the data, these values can be obtained with an integrated sample (see Fig. 25-28) or a grab sample (see Fig. 25-29). In addition, the instrumental analyzer... 

With the grab sampling technique, a samphng probe is placed at the center of the stack, and a sample is drawn direcfly into an Orsat analyzer or a Fyrite-type combustion-gas analyzer. The sample is then analyzed for carbon dioxide and oxygen content. With these data, the diy molecular weight of the gas stream can then be calculated. 

The instrumental analyzer procedure, EPA Method 3A, is commonly used for the determination of oxygen and carbon dioxide concentrations in emissions from stationary sources. An integrated continuous gas sample is extracted from the test location and a portion of the sample is conveyed to one or more instrumental analyzers for determination of O9 and CO9 gas concentrations (see Fig. 25-30). The sample gas is conditioned prior to introduction to the gas analyzer by removing particulate matter and moisture. Sampling is conducted at a constant rate for the entire test run. Performance specifications and test procedures are provided in the method to ensure reliable data. 

When the operating conditions are uniform and steady (there are no fluctuations in flow rate or in concentration of CO in the gas stream), the continuous sampling method can be used. A sampling probe is placed in the stack at any location, preferably near the center. The sample is extracted at a constant sampling rate. As the gas stream passes through the sampling apparatus, any moisture or carbon dioxide in the sample gas stream is removed. The CO concentration is then measured by a nondispersive infrared analyzer, which gives direct readouts of CO concentrations. 

Carbon monoxide and carbon dioxide can be measured using the FTIR techniques (Fourier transform infrared techniques see the later section on the Fourier transform infrared analyzer). Electrochemical cells have also been used to measure CO, and miniaturized optical sensors are available for CO 2 monitoring. 

Gases analyzed include hydrocarbons, carbon monoxide, carbon dioxide, sulfur dioxide, sulfur trioxide, nitrogen oxides (also nitrous oxide, N2O), hydrogen chloride, hydrogen cyanide, ammonia, etc. 

The flue gases analyzed will be one or more of carbon dioxide, carbon monoxide and oxygen. If carbon dioxide alone is measured, it is possible to draw erroneous conclusions, as the level will peak at stoichiometric and reduce in both the excess air and air deficiency regions. It is essential to measure another flue gas to obtain a reliable assessment of burner performance. 

Braune and Strassman8 measured the concentration of iodine in gaseous carbon dioxide at pressures up to 50 atm from 32° to 98°C. They passed the carbon dioxide over an excess of solid iodine and analyzed the effluent mixtures. Their pressures were too low to find the saturation vapor pressures or to show whether or not critical end points were formed. 

Effects of Cold Gas Recycle and Approach to Equilibrium. Product gases resulting from various CGR ratios were analyzed (Table XI). For the experiments tabulated, a decrease in the cold recycle ratio resulted consistently in increases in the product gas concentrations of water vapor, hydrogen, and carbon dioxide and a decrease in methane concentration. These trends may be noted in experiment HGR-12 as the CGR ratio decreased from 8.7 1 to 1.2 1, in experiment HGR-13 as it increased from 1.0 1 to 9.1 1, and in experiment HGR-14 as it decreased from 3.0 1 to 1.0 1. These trends indicate that the water-gas shift reaction (CO + H20 —> C02 + H2) was sustained to some degree. Except for the 462-hr period in experiment HGR-14, the apparent mass action constants for the water-gas shift reaction (based on the product gas compositions in Table XI) remained fairly constant at 0.57-1.6. These values are much lower than the value of 11.7 for equilibrium conversion at 400°C. In... 

NOTE Pure condensate, for all practical purposes, does not conduct electricity (very pure condensate has an electrical conductivity of perhaps 0.1 to 0.05 pS/cm), and any impurities in the steam are reflected in an increase in conductivity. For the highest precision conductivity measurement testing, any volatile materials present such as ammonia (NH3) and carbon dioxide (C02) must be removed. Equipment such as a Larson-Lane Analyzer (which condenses the steam and passes it through an acid-regenerated cation resin) is employed to remove NHy while C02 is removed by reboiling. 

Tadaki and Maeda (Tl) examined the desorption of carbon dioxide from water in a bubble-column and analyzed the experimental results under the assumption that while the gas phase moves in piston flow, the liquid undergoes axial mixing that can be characterized by the diffusion model. (Shulman and Molstad, in contrast, assumed piston flow for both phases.) Only poor agreement was obtained between the theoretical model and the experimental... 

Let s see how to analyze the data, which are the initial mass of the compound and the masses of the water and carbon dioxide produced in the combustion of the compound. In the presence of excess oxygen, each carbon atom in the compound ends up in one molecule of carbon dioxide. Therefore, we can write... 

The zeolite fixed into the reactor ijras dried by carbon dioxide at 623K fw lb. The CHO dissolved into methanol (SO ma %) was si lied by a micio f der at constant flow tate to e poiator. The vapor diluted by carbon dioxide P0mol%) was fed to flie tssiAor. The n ctor effluent was collected at prescribed time intervals to and analyzed by a gas chromah aph equipped glass with column (40m). 

Compounds that do not decompose cleanly into their elements must be analyzed by other means. Combustion analysis is particularly useful for determining the empirical formulas of carbon-containing compounds. In combustion analysis, an accurately known mass of a compound is burned in a stream of oxygen gas. The conditions are carefully controlled so that all of the carbon in the sample is converted to carbon dioxide, and all of the hydrogen is converted to water. Certain other elements present in the sample are also converted to their oxides. 

The electrolytes Na", and Cl are second only to glucose in being the most frequently run hospital tests. Many clinical chemistry analyzers now contain an ISE module for electrolyte analysis. Most commonly the module will consist of a Na -glass electrode, a valinomycin/PVC electrode, a Ag/AgCl pellet or a quaternary ammonium ion/PVC electrode and a reference electrode. A selective electrode for the bicarbonate ion continues to elude workers in the field. An indirect measurement of HCOf must be made. The sample is usually reacted with acid to evolve carbon dioxide gas which is measured with a traditional Severinghaus type CO2 electrode. Alternatively, the sample is treated with base to convert HCO to CO3 and a carbonate ion-selective electrode is used In this manner, the complete primary electrolyte profile is obtained electrochemically. 

Carbon dioxide fugacity fcOi- CO2 fugacity (/coa) of ore fluids is estimated based on CO2 concentration of fluid inclusions analyzed. By using equilibrium constant of the reaction, C02(g) + H2O = H2CO3, and assuming uh20 to be unity, /CO2 can be estimated. 

The photodegradation of para-aramid in an 0 atmosphere allows the differentiation between the accelerated experimental photooxidative conditions from its usual daylight exposure effects. This study illustrated an estimation of the rates of photooxidation of a commercial para-aramid product (i.e., DuPont s Kevlar-29 woven fabric) based on the oxygen-18-labelled carbon dioxide ( CC and CC ) decarboxylated from the sample. The oxygen-18-labelled atoms, which are inserted in the macromolecules, were analyzed for the photodegradation processes. This technique also allows the radial l O-distribution measurement from the fiber surface toward the fiber center. 

Since many new substances of interest are very poorly soluble in water, the assessment of the pKa in aqueous solution can be difficult and problematic. Potentiometry can be a quick technique for such assessment, provided the solubility of the substance is at least 100 pM. (Solutions as dilute as 10 pM can still be analyzed, but special attention must be given to electrode calibration, and ambient carbon dioxide must be excluded.) If the substance is soluble to only 1-10 pM and possesses a pH-sensitive UV chromophore, then spectrophotometry can be applied. CE methods may also be useful since very small sample quantities are required, and detection methods are generally quite sensitive. 

Clinical chemistry, particularly the determination of the biologically relevant electrolytes in physiological fluids, remains the key area of ISEs application [15], as billions of routine measurements with ISEs are performed each year all over the world [16], The concentration ranges for the most important physiological ions detectable in blood fluids with polymeric ISEs are shown in Table 4.1. Sensors for pH and for ionized calcium, potassium and sodium are approved by the International Federation of Clinical Chemistry (IFCC) and implemented into commercially available clinical analyzers [17], Moreover, magnesium, lithium, and chloride ions are also widely detected by corresponding ISEs in blood liquids, urine, hemodialysis solutions, and elsewhere. Sensors for the determination of physiologically relevant polyions (heparin and protamine), dissolved carbon dioxide, phosphates, and other blood analytes, intensively studied over the years, are on their way to replace less reliable and/or awkward analytical procedures for blood analysis (see below). 

The sample handling system is diagrammed in Figure 3. As shown, the concentrations of oxygen, carbon monoxide, and carbon dioxide were on a dry basis because the water was removed. The water vapor analyzer did not function properly because condensation occurred in the instrument when water vapor was too high, often exceeding 20 percent. By using some approximations in the calculations, we did not need the exact concentration of water. 

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