Effects of interfering gases in electrochemical sensors NH

Electrochemical sensors used for toxic gas measurement. In this paper construction EC sensor and principle of operation has been described. The results of research on the influence of interfering gases on the readings of detectors containing ammonia and nitric oxide (IV) electrochemical sensors are presented. Span gases were used in the tests: 100 ppm CO, 25 ppm H2S, 25 ppm NH3, 10 ppm NO, 25 ppm NO2, 10 ppm Cl2, 10 ppm HCN, 10 ppm HCl, 2% vol. H2, 2.5% by volume CH4, 0.35% by volume of C5H12. The conducted research indicates that the presence of chlorine, hydrogen chloride, hydrogen cyanide, carbon monoxide and saturated hydrocarbons in the atmosphere does not affect the work of the ammonia electrochemical sensor. In the case of this sensor, there was a significant cross effect in relation to hydrogen sulphide and hydrogen. The administration of these substances indicated the presence of ammonia outside the measuring range (200 ppm). In the measurements using the NO2 sensor, in most cases negative interference was found. The test results indicate that the measurements made with electrochemical sensors may be subject to error in the presence of interfering gases. The results obtained may be both understated and overstated

Liquidation of ammonia clouds using a mobile turbine rescue and firefighting system

Given its extensive industrial use and chemical properties ammonia is a source of serious hazards in the event of its uncontrolled releases. The mobile turbine rescue and fire-fighting system (MTSRG), equipped with a special SO3-W aircraft turbine with 10 kN power and water efficiency of 6 m3/min, can be used to liquidate spatial gas clouds by diluting them with combustion gases and sorption on the surface of the produced water microdroplets. The publication presents calculations related to the effectiveness of the system during the uncontrolled release of ammonia from a pressure vessel. To estimate the performance of this system, use was made of water stream droplet size research, kinetics studies of ammonia sorption, SO3-W turbine parameters at a safe working distance, as well as results of ammonia concentration simulation using the ALOHA program. A combined simulation carried out for a rupture of DN100 pipe supplying liquid ammonia to spherical tank with a diameter of 16.6 m and filled in 70% showed that it is theoretically possible to reduce the ammonia concentration by as much as 95.75% while the vehicle is operating at a working distance of 60 meters from the rupture. The exhaust gases together with the entrained air contribute mainly to the reduction of the concentration of ammonia through the mechanism of dilution (91.6%). Water mist generated by the vehicle is theoretically responsible for the reduction of ammonia concentration by only 4.15%

Czy można w prosty sposób zidentyfikować polimer?

Plastics are raw materials that play a very important role in our lives. We can find them in medical devices, cell phones, clothes, cars, furniture, cutlery, plates, toys, bottles etc. Their diversity and quantity mean that we have no awareness of which substances we use. The aim of the research was to develop a scheme allowing the simple identification of the most commonly used synthetic polymers. Hazards occurring during their use and burning under uncontrolled conditions were also determined.Tworzywa sztuczne to surowce odgrywające bardzo istotną rolę w naszym życiu. Możemy je znaleźć w wyrobach medycznych, telefonach komórkowych, ubraniach, samochodach, meblach, sztućcach, talerzach, zabawkach, butelkach itp. Ich różnorodność i ilość sprawia, że nie mamy świadomości z jakich substancji korzystamy. Celem badań było opracowanie schematu pozwalającego na prostą identyfikację najczęściej stosowanych polimerów syntetycznych. Określono także zagrożenia występujące podczas ich użytkowania i spalania w niekontrolowanych warunkach

Study of water curtain effectiveness to fight against vapours of methyl acetate during uncontrolled release

The paper presents results of studies concerning the effectiveness of water curtains in eliminating airborne vapours of methyl acetate. It was found that for methyl acetate the determined effectiveness of water curtains was 13.57 times lower than that of ammonia. In practical terms the absorption rate of methyl acetate vapours equalled to the absorption rate set out for ethanol, but was much lower than for methanol. The obtained results have pointed to the efficiency of water curtains in incidents that comprise uncontrolled release of methyl acetate

Wchłanianie preparatów do ochrony drewna przez sorbenty naturalne o różnym stopniu rozdrobnienia

The growing demand for the impregnated wood products increases the production of wood preservatives, which can more likely be released into the environment. The vast majority of wood preservatives are the poisonous substances for the living organisms. Due to their properties, these measures may pose a threat to the environment and human health in the event of uncontrolled release. Their entry into the environment may take place at the stage of production, storage, transport or during various technological processes related to the wood processing. Threats associated with their uncontrolled release must be removed by the Fire Service specialized units of chemical and ecological rescue . The aim of the research was to analyze the impact of the degree of fragmentation of selected natural sorbents on the sorption of wood preservatives. A sorbent with a smaller grain size showed better sorption properties compared to the same sorbent with the larger grains due to the fact that it absorbed a larger total surface.Rosnące zapotrzebowanie na impregnowane wyroby z drewna powoduje wzrost produkcji środków ochrony drewna, co wiąże się z większym prawdopodobieństwem wystąpienia możliwości uwolnienia tych środków do środowiska. Zdecydowana większość środków przeznaczonych do ochrony drewna są to substancje trujące dla organizmów żywych. Z uwagi na swoje właściwości środki te, w przypadku niekontrolowanego uwolnienia, mogą stwarzać zagrożenie zarówno dla środowiska, jak i dla zdrowia człowieka. Przedostanie się ich do środowiska może nastąpić na etapie produkcji, magazynowania, transportu lub w czasie trwania różnych procesów technologicznych związanych z obróbką drewna. Zagrożenia związane z ich niekontrolowanym uwolnieniem muszą być usuwane przez specjalistyczne jednostki ratownictwa chemicznego i ekologicznego PSP. Celem badań była analiza wpływu stopnia rozdrobnienia wybranych sorbentów naturalnych na sorpcję środków ochrony drewna. Sorbent o mniejszym rozmiarze ziaren wykazywał lepsze właściwości sorpcyjne w porównaniu do tego samego sorbentu o większych ziarnach z uwagi na to, że chłonął większą powierzchnią całkowitą

Influence of Micro- and Macrostructure of Atomised Water Jets on Ammonia Absorption Efficiency

Ammonia has a very wide range of applications. Its worldwide production exceeds 230 million tonnes per year. Due to its properties, ammonia causes a serious threat to human life and health when released uncontrolled into the environment. Research carried out in the word shows that this substance may be effectively neutralised by absorption in water. The aim of research described in this paper is to determine the influence of key parameters of the micro- and macrostructure of water streams on the course of the ammonia absorption process. During the studies, different types of water nozzles were used, with similar efficiency and supply pressure, but characterised by different parameters of the micro- and macrostructure of the produced stream. The experiments were divided into two stages. In the first one, the macro- and microparameters of the streams were measured, while in the second one, the changes in ammonia concentration were established during delivering spray jet generation by different nozzles. Among the basic parameters of the macrostructure, the spray angle and liquid distribution in the jet (spray intensity) were determined, while for the microstructure, the droplet size distribution and mean droplet diameters were measured. Ammonia concentration was measured by means of a photoionisation detector (PID). In order to evaluate the absorption efficiency of different water spray jets, the apparent absorption rate (kp) and the half-time of concentration reduction (t½) in the kinetic range were established. The study has confirmed that atomised water jets are an effective method for neutralising ammonia released into the environment. The research has a practical aspect and shows that the structure of atomised water streams influence the course of the absorption process. Increasing the spray angle in a conical stream leads to an improvement in the quality of water atomisation and helps increase ammonia absorption. Moreover, it was also observed that for the absorption of spatial ammonia clouds, use should be made of nozzles generating streams with full spray cones and high uniformity of spray and dispersion

Use of special mobile devices to identify hazardous substances on the incident site

Postęp cywilizacji prowadzi często do powstawania zagrożeń związanych z wyciekiem substancji niebezpiecznych. W celu zabezpieczenia miejsca zdarzenia angażowana jest Państwowa Straż Pożarna. Ratownicy przybywający na miejsce zdarzenia nie mają świadomości, z jaką substancją mają do czynienia. Z tego względu bardzo ważny jest aspekt identyfikacji nieznanych substancji zarówno pod względem jakościowym, jak i ilościowym. Celem niniejszych badań była ocena możliwości wykorzystania dwóch mobilnych urządzeń analitycznych stosowanych przez Państwową Straż Pożarną do identyfikacji wybranych substancji niebezpiecznych. W warunkach laboratoryjnych przygotowano cztery substancje, czyli alkohol metylowy, amoniak, epichlorohydrynę oraz proszek czyszczący, które następnie identyfikowano przy pomocy dwóch mobilnych urządzeń analitycznych − StreetLab Mobile i Mobile IR, które to urządzenia wykorzystują odpowiednio spektroskopię Ramana i podczerwień (IR). W przypadku alkoholu metylowego oraz epichlorohydryny oba urządzenia wykryły analizowaną substancję. W przypadku amoniaku, a także proszku czyszczącego, żadne z zastosowanych urządzeń nie wykryło analizowanej substancji. Urządzenie StreetLab w przypadku amoniaku wykrył kwas 4-hydroksyfenoksyoctowy. Zaobserwowano, iż w przypadku wysokiego rozcieńczenia próbek brak jest możliwości ich identyfikacji, co było pokazane na przykładzie 25% roztworu amoniaku do wody.The progress of civilization often leads to incidences of leakage of dangerous substances which involve the State Fire Service to secure the incident site. However, rescuers arriving at the spot are unaware of what substance was splatted. For this reason, it is important to identify the unknown substance both qualitatively and quantitatively. The aim of the research was to assess the possibility of using two mobile analytical devices used by the State Fire Service to identify selected hazardous substances. In the laboratory conditions 4 substances were prepared, i.e. methyl alcohol, ammonia, epichlorohydrin, cleaning powder, which were then identified with two mobile devices, i.e. StreetLab Mobile and Mobile IR, which use the Raman spectroscopy and the infrared (IR). In case of methyl alcohol and epichlorohydrin, both devices detected the substance. In case of ammonia, as well as in the cleaning powder, none of the tested devices detected them. What is more, the StreetLab detected 4-hydroxyphenoxyacetic acid instead of ammonia. Both devices, which use the phenomenon of the Raman spectroscopy and the infrared IR, are used to analyze unknown compounds in chemical and ecological rescue in the State Fire Service. It was observed that in case of high dilution of samples both devices were not able to identify the tested substance or the results were incorrect. Moreover, the lack of detection of high-dilution samples was observed, as exemplified by the comparison of 25% solution of ammonia to water

The application of stand-off infrared detection to identify air pollutants

Fourier-transform infrared spectroscopy (FT-IR) enables the passive detection and identification of chemical agent clouds from distances. It can be used for the monitoring of large spaces and protection of industrial installations outside buildings. The aim of the study was show the possibilities and limitations of passive FT-IR. In studies done by the Faculty of Fire Safety Engineering at the Main School of Fire Service were used spectrometer RAPID (Remote Air Pollution Infrared Detector), Bruker Daltonics Company. Hazardous substances such as acetone, methanol, ammonia was identified on-line from several observation points at 25 m, 50 m and 75 m. The tests were carried out at various meteorological conditions. The results indicate that remote infrared detection allows detecting hazardous chemical agents in the atmosphere from a distance. Nevertheless, meteorological and terrain conditions have a big impact on the measurement results. During measurements, the detector indicated the presence of other substances. Moreover, it was found that under cloudy and windy weather, remote detection is not possible

Influence of Micro- and Macrostructure of Atomised Water Jets on Ammonia Absorption Efficiency

Ammonia has a very wide range of applications. Its worldwide production exceeds 230 million tonnes per year. Due to its properties, ammonia causes a serious threat to human life and health when released uncontrolled into the environment. Research carried out in the word shows that this substance may be effectively neutralised by absorption in water. The aim of research described in this paper is to determine the influence of key parameters of the micro- and macrostructure of water streams on the course of the ammonia absorption process. During the studies, different types of water nozzles were used, with similar efficiency and supply pressure, but characterised by different parameters of the micro- and macrostructure of the produced stream. The experiments were divided into two stages. In the first one, the macro- and microparameters of the streams were measured, while in the second one, the changes in ammonia concentration were established during delivering spray jet generation by different nozzles. Among the basic parameters of the macrostructure, the spray angle and liquid distribution in the jet (spray intensity) were determined, while for the microstructure, the droplet size distribution and mean droplet diameters were measured. Ammonia concentration was measured by means of a photoionisation detector (PID). In order to evaluate the absorption efficiency of different water spray jets, the apparent absorption rate (kp) and the half-time of concentration reduction (t½) in the kinetic range were established. The study has confirmed that atomised water jets are an effective method for neutralising ammonia released into the environment. The research has a practical aspect and shows that the structure of atomised water streams influence the course of the absorption process. Increasing the spray angle in a conical stream leads to an improvement in the quality of water atomisation and helps increase ammonia absorption. Moreover, it was also observed that for the absorption of spatial ammonia clouds, use should be made of nozzles generating streams with full spray cones and high uniformity of spray and dispersion

Evaluation of the microstructure of water jet produced by a full cone spiral nozzle

Strumienie rozproszone są powszechnie wykorzystywane m.in. do gaszenia, chłodzenia oraz absorpcji substancji niebezpiecznych. W celu zoptymalizowania procesu, w którym wykorzystywane są rozpylacze, niezbędna jest wiedza na temat mikroi makrostruktury wytwarzanych przez nie strumieni. Parametry mikrostruktury strumienia rozpylonego, takie jak średnia średnica kropel czy widmo rozpylenia są uzależnione zarówno od cech konstrukcyjnych dysz, jak również ilości i ciśnienia przepływającej cieczy W artykule przedstawiono wyniki badania mikrostruktury strugi generowanej przez wirową dyszę spiralną TF 6 NN o pełnym stożku zraszania. Badania były przeprowadzone przy różnych ciśnieniach zasilania i w czterech punktach strefy zraszania. Wybór tych punktów był poprzedzony wyznaczeniem rozkładów intensywności zraszania. Do określenia średnich średnic powierzchniowych kropel i widma rozpylenia wykorzystano metodę fotoelektryczną, zaś intensywność zraszania wyznaczono metodą kubełkową. Na podstawie przeprowadzonych badań udowodniono, że w strefie zraszania występują istotne dysproporcje w parametrach mikrostrukturalnych strumienia. Wykazano, że największa ilość wody wypływająca z badanej dyszy jest kierowana do głównego pierścienia zraszania, gdzie występują największe średnie średnice kropel. Zmiana ciśnienia zasilania dyszy nie powoduje istotnych zmian parametrów strugi w centralnej części strefy zraszania. W tym obszarze widmo rozpylenia, intensywność zraszania i średnia średnica kropel, niezależnie od ciśnienia zasilania, były zbliżone. Ponadto udowodniono, że w strefie położonej bezpośrednio pod dyszą odnotowuje się największy stopień rozpylenia strugi.Dispersed streams are widely used for such purposes as extinguishing, cooling and absorbing hazardous substances. In order to optimise the process in which atomisers are used, it is necessary to understand the micro- and macrostructure of the jets they produce. The parameters of a spray jet microstructure, such as the average droplet diameter or the spray spectrum, are dependent on both the design features of the nozzles and the quantity and the pressure of flowing liquid. This paper presents the results of a study of the microstructure of a jet generated by the vortex spiral nozzle TF 6 NN with a full sprinkling cone. The research was executed at various supply pressures and in four points of the spray zone. The selection of these points was preceded by the determination of spray intensity distributions. The photoelectric method was used to determine the mean surface diameters of droplets and the spray spectrum, while the spray intensity was established using the bucket method. On the basis of the performed tests it has been proven that significant disproportions in the microstructural parameters of the spray occur in the sprinkling zone. It was shown that the tested nozzle directs the largest amount of water to the main spray ring, where the largest average droplet diameters occur. Changing the nozzle supply pressure does not cause significant changes in the spray parameters in the central part of the spray zone. In this area, the spray spectrum, spray intensity and mean droplet diameter were similar regardless of the supply pressure. Moreover, it has been proven that in the zone located directly under the nozzle there is the highest degree of spray jet atomisation