Monitoring, continuous

If there are hydrocarbons present in the formation that is being drilled, they will show in the cuttings as oil stains, and in the mud as traces of oil or gas. The gas in the mud is continuously monitored by means of a gas detector. This is often a relatively simple device detecting the total combustible gas content. The detector can be supplemented by a gas chromatograph, which analyses the composition of the gas. 

Sensors on the tree allow the control module to transmit data such as tubing head pressure, tubing head temperature, annulus pressure and production choke setting. Data from the downhole gauge is also received by the control module. With current subsea systems more and more data is being recorded and transmitted to the host facility. This allows operations staff to continuously monitor the performance of the subsea system. 

The specific results of well over 1 year of continued monitoring will be discussed in a second paper. It is pointed out here that the AEBIL monitoring system installed in the power plant for the above monitoring purposes has efficiently and continuedly performed during this time interval, with no instrumentation reliability problems. 

In the majority of practical finite element simulations the mesh generation is conducted in conjunction with an interactive graphics tool to allow feedback and continuous monitoring of the computational grid. 

The short-term exposure of humans, animals, and plants to gaseous pollutants is more severe than that for pollutants in other matrices. Since the composition of atmospheric gases can show a substantial variation over a time, the continuous monitoring of atmospheric gases such as O3, CO, SO2, NH3, H2O2, and NO2 by in situ sampling is important. 

A second approach to gravimetry is to thermally or chemically decompose a solid sample. The volatile products of the decomposition reaction may be trapped and weighed to provide quantitative information. Alternatively, the residue remaining when decomposition is complete may be weighed. In thermogravimetry, which is one form of volatilization gravimetry, the sample s mass is continuously monitored while the applied temperature is slowly increased. 

Environmental Applications Although ion-selective electrodes find use in environmental analysis, their application is not as widespread as in clinical analysis. Standard methods have been developed for the analysis of CN , F , NH3, and in water and wastewater. Except for F , however, other analytical methods are considered superior. By incorporating the ion-selective electrode into a flow cell, the continuous monitoring of wastewater streams and other flow systems is possible. Such applications are limited, however, by the electrode s response to the analyte s activity, rather than its concentration. Considerable interest has been shown in the development of biosensors for the field screening and monitoring of environmental samples for a number of priority pollutants. 

Automated analyzers may be used for continuous monitoring of ambient poUutants and EPA has developed continuous procedures (23) as alternatives to the referenced methods. Eor source sampling, EPA has specified extractive sampling trains and analytical methods for poUutants such as SO2 and SO [7446-11-9] sulfuric acid [7664-93-9] mists, NO, mercury [7439-97-6], beryUium [7440-41-7], vinyl chloride, and VOCs (volatile organic compounds). Some EPA New Source Performance Standards requite continuous monitors on specified sources. 

Continuous monitoring for the presence of fluorine gas in the workplace may be accompHshed using detectors available from Mine Safety Apphances (Pittsburgh, Pa.) or FIT (Exton, Pa.). 

A iridine traces in aqueous solution can be determined by reaction with 4-(p-nitroben25l)pyridine [1083-48-3] and potassium carbonate [584-08-7]. Quantitative determination is carried out by photometric measurement of the absorption of the blue dye formed (367,368). Alkylating reagents interfere in the determination. A iridine traces in the air can be detected discontinuously by absorption in Folin s reagent (l,2-naphthoquinone-4-sulfonate) [2066-93-5] (369,370) with subsequent chloroform extraction and hplc analysis of the red dye formed (371,372). The detection limit is ca 0.1 ppm. Nitrogen-specific thermal ionisation detectors can be used for continuous monitoring of the ambient air. 

Direct rea ding. a instmments Continuous monitors Pumps—sorbent sampler Detector tubes Passive badges... 

Waste Gas Streams. Several methods of decomposing phosgene in waste gas streams are used. The outlet gas from the phosgene decomposition equipment is continuously monitored for residual phosgene content to ensure complete decomposition. 

The pilot plant must also be carehiUy designed so that its control and safety systems are "fad-safe" and any unexpected equipment or utdity fadure brings the unit into a safe and de-energized condition. Unexpected or rapid process changes, if they can herald or lead to dangerous conditions (eg, mnaway exothermic reaction), should be continuously monitored by appropriate instmmentation and suitable automatic action provided (1,55—67). 

Miniature Continuous Monitor, Tech. Bull, MDA Scientific, Inc. Park Ridge, lU., Dec. 1974. 

Protective measures iavolve prompt detection and adequate ventilation. Continuous monitoring is recommended to signal an evacuation alarm if the workplace concentration exceeds 70 mg/m (50 ppm) and a warning alert if it is present at 15—70 mg/m (10—50 ppm). 

The Reich test is used to estimate sulfur dioxide content of a gas by measuring the volume of gas required to decolorize a standard iodine solution (274). Equipment has been developed commercially for continuous monitoring of stack gas by measuring the near-ultraviolet absorption bands of sulfur dioxide (275—277). The deterrnination of sulfur dioxide in food is conducted by distilling the sulfur dioxide from the acidulated sample into a solution of hydrogen peroxide, foUowed by acidimetric titration of the sulfuric acid thus produced (278). Analytical methods for sulfur dioxide have been reviewed (279). 

Submerged culture oxidizers can also be operated on a continuous basis. Continuous monitoring of ethanol and acetic acid concentrations, temperature, and aeration rates permit control of feed and withdrawal streams. Optimum production, however, is achieved by semicontinuous operation because the composition of vinegar desired in the withdrawal stream is so low in ethanol that vigorous bacterial growth is impeded. Bacterial... 

The purified ziac solution is fed to the electrolyte recirculating stream at a rate that holds the composition of the electrolyte constant, commonly ranging from 100—200 g H2SO4 and 45—70 g Zn/L. Continuous monitoring of the density and conductivity of the spent acid aids ia control. This is important siace the range of acidity is narrow for maximum current efficiency at any given current density. 

Thermal-Conductivity Analyzer. The thermal-conductivity analy2er operates on the principle that the loss of heat from a hot wire by gaseous conduction to a surface at a lower temperature varies with the thermal conductivity of the gas, and is virtually independent of pressure between 1.3 kPa (10 mm Hg) and 101 kPa (1 atm). This technique is frequently used in continuous monitors for tritium in binary gas mixtures for immediate detection of process change. 

There are important economic consequences of a process being out of control for example, product waste and customer dissatisfaction. Hence, statistical process control does provide a way to continuously monitor process performance and improve product quahty. A typic process may go out of control due to several reasons, including... 

All scales reqmre continuous monitoring to assure that the desired set weight is maintained and does not drift off because of changes in product bulk-density or flow characteristics. Microprocessors can perform this task automatically. 

NAAQS. Continuous monitoring is also required for other CAA pollutants for which the EPA or the state determines that monitoring is necessary. The EPA or the state may exempt any CAA pollutant from these monitoring requirements if the maximum air-quahty impact of the emissions increase is less than the values in Table 25-6 or if present concentrations of the pollutant in the area that the new source would affect are less than the Table 25-6 values. The EPA or the state... 

For LOCs of 5 percent and greater, the O9 concentration should not exceed 60 percent of the LOC, but with continuous monitoring the O9 may be kept 2 percent below the LOC (NFPA 69, 1992). Neutronics, Inc., of Exton, Pennsylvania, supplies an inerting control system that has had wide apphcation in many industries. 

From this it can be seen that vibration is the universal manifestation that something is wrong. Therefore, many units are equipped with instruments that continuously monitor vibration. Numerous new instruments for vibration analysis have become available. Frequency can be accurately determined and compared with computations, and by means of oscilloscopes the waveform and its harmonic components can be analyzed. Such equipment is a great help in diagnosing a source of trouble. 

VACUUM RADIATING DESORPTION AND INFRARED SPECTROMETRY (VRDIR) FOR CONTINUOUS MONITORING OF SUSPENDED PARTICULATE ORGANIC MATTERS IN ATMOSPHERE... 

Uranium and thorium are the first members of natural radioactive chain which makes their determination in natural materials interesting from geochemical and radioecological aspect. They are quantitatively determined as elements by spectrophotometric method and/or their radioisotopes by alpha spectrometry. It is necessary to develop inexpensive, rapid and sensitive methods for the routine researches because of continuous monitoring of the radioactivity level. 

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