Real-time Gas Monitoring System Research Articles

A real-time gas monitoring system based on ion mobility spectrometry for workplace environmental measurements.

A volatile organic compounds (VOC) gas monitor was developed using an ion mobility spectrometer (IMS). It was designed for real-time monitoring in work environments, where gas chromatography/mass spectrometry (GC/MS) does not perform well. To evaluate the identification capability, response time, and quantitative accuracy of this device, experiments were conducted using methyl ethyl ketone. This is widely used in many factories, and its short-term exposure limit (STEL) has been set by the American Conference of Governmental Industrial Hygienists. Because the ionizable amount of methyl ethyl ketone has already been exceeded in STEL value of 300 ppm which belongs to the measurement range of interest in this study, this study estimated the peak shift amount rather than the peak intensity. Calibration curves with high accuracy were obtained in a range including 300 ppm which is the STEL of methyl ethyl ketone. The results of the experiment suggest that the device can be used for monitoring chemical substances in a work environment.

Infrared Hollow Optical Fiber Probe for Localized Carbon Dioxide Measurement in Respiratory Tracts.

A real-time gas monitoring system based on optical absorption spectroscopy is proposed for localized carbon dioxide (CO2) measurement in respiratory tracts. In this system, a small gas cell is attached to the end of a hollow optical fiber that delivers mid-infrared light with small transmission loss. The diameters of the fiber and the gas cell are smaller than 1.2 mm so that the probe can be inserted into a working channel of common bronchoscopes. The dimensions of the gas cell are designed based on absorption spectra of CO2 standard gases in the 4.2 μm wavelength region, which are measured using a Fourier-transform infrared spectrometer. A miniature gas cell that is comprised of a stainless-steel tube with slots for gas inlet and a micro-mirror is fabricated. A compact probing system with a quantum cascade laser (QCL) light source is built using a gas cell with a hollow optical fiber for monitoring CO2 concentration. Experimental results using human breaths show the feasibility of the system for in-situ measurement of localized CO2 concentration in human airways.

IJARCCE - Computer and Communication Engineering

A cost-effective, Automated Unified System for Liquefied Petroleum Gas (LPG) booking, leakage detection, real time gas monitoring system and automatic controlling of LPG regulator is proposed in this paper. The aim of this paper is to monitor for LPG leakage to avoid fire accidents providing house safety feature where security has been an important issue. The system detects the leakage of the LPG using gas sensor MQ6 and alerts the consumer about the gas leakage by sending SMS using GSM module and simultaneously activating the alarm and exhaust fan. The system additionally provides the automatically controlling of LPG regulator. To avoid the blast this system will disconnect the main power supply using relay. The additional advantage of the system is that it continuously monitors the level of the LPG present in the cylinder using weight sensor and automatically books the cylinder using a GSM module.

Real-time drill mud gas logging at the USDP-4 drilling, Unzen volcano, Japan

During the Unzen conduit drilling project USDP-4, the gas phase dissolved in the drill mud was continuously analyzed. Starting from the volcano's north flank an almost complete gas profile was achieved to the final depth of 1995.75 m in July 2004. Limitations were given due to the extremely difficult drilling conditions. The highly fractured rock formation led to loss of drill mud circulation in the shallow parts of the drill hole. Significant fluid inflow horizons did not occur above 800 m (drill string length). Starting from that depth on, invading fluids were detected with the real-time gas monitoring system. Major variations in the mud gas composition occurred only below a depth of 1000 m. Of major importance are fluid inflow zones with high 3He/ 4He at depths of 1555 m (7.3 R A), 1755.5 m (7.48 R A) and 1977.4 m (6.21 R A). These values indicate a significant influence of fluids with mantle signature. Furthermore, enhanced methane, radon and helium concentrations were also detected at specific depth. These detected major fluid- and gas inflow horizons may be able to explain magmatic degassing processes, related to the Unzen's eruption mechanism. This is generally true for the main fluid inflow zones and especially for the detected inflows at 1555 m, 1755.5 m and 1977.4 m. Furthermore, a correlation between lithology and gas composition was observed. Higher H 2S concentrations were detected while drilling in pyrite-rich rocks. Cracks and fissures as well as lithological changes are often correlated with increasing amounts of gas. Trends with depth, from a minor to a more magmatic influenced regime were observed together with a change in hydrothermal alteration of the surrounding rock. This corresponds with the magmatic conduit zone which was penetrated at a depth of 1600 m, and supports the model of a high influence of hydrothermal fluid, accelerating cooling and mineral alteration.

Low-Cost Real-Time Gas Monitoring Using a Laser Plasma Induced by a Third Harmonic Q-Switched Nd-YAG Laser

A gas plasma induced by a third harmonic Nd-YAG laser with relatively low pulsed energy (about 10 mJ) has favorable characteristics for gas analysis due to its low background characteristics, nevertheless a high power fundamental Nd-YAG laser (100-200 mJ) is widely used for laser gas breakdown spectroscopy. The air plasma can be used as a low-cost real-time gas monitoring system such that it can be used to detect the local absolute humidity, while a helium plasma can be used for gas analysis with a high level of sensitivity. A new technique using a helium plasma to improve laser ablation emission spectroscopy is proposed. Namely, the third harmonic Nd-YAG laser is focused at a point located some distance from the target in the 1-atm helium surrounding gas. By using this method, the ablated vapor from the target is excited through helium atoms in a metastable state in the helium plasma.