Exploration of Detection Technology about Arsenic Content in Natural Gas and Application

Abstract

Although volatile arsenides in natural gas are usually in trace amounts, the service life of a catalyst in natural gas processing can still be shorten by them. Environmental pollution is caused by distribution of As into the atmosphere through gas burning. Health and safety issues happen for workers in close contact with unprocessed gas during exploration and handling. As an important part of natural gas product quality inspection, the technology of arsenic content detection in natural gas needs to break through immediately. We confirmed the feasibility of the two solutions as the adsorption of arsenic through choosing an arsenic adsorbent in natural gas and exploring multi-stage, circulating, and subsequent instrument methods. We selected concentrated nitric acid and silver nitrate solution as the adsorbents and tested the solutions by inductively coupled plasma mass spectrometry (ICP−MS). The results were obtained that the highest absorption efficiency of silver nitrate solution was 98.7%, the average of which was 80.31%, of which concentrated nitric acid could be up to 45%. Detection was also taken in the gas production plant using the methods mentioned above. Moreover, sandstone gas from fields of different provinces was also collected to be detected in the laboratory. We could draw the conclusion from the data that the two absorbents could reach the minimum detection value of the instrument in both gas field and the laboratory. The method of silver nitrate solution was better, and concentrated nitric acid should be used when detecting high H 2 S gas. Some wells were of higher arsenic content than the safety standard line, in which proper treatment should be taken.

Arsenic metabolism in technical biogas plants: possible consequences for resident microbiota and downstream units

“…Even in the most contaminated plants included in this study, the total As content in the gas phase was in the pg NL −1 range and thus well below the critical limits for an addition to the gas grid, e.g. in the UK (< 1 ppm, respectively 0.1 µg NL −1 ) (Bright et al 2011), but also below the safety standard of the arsenic concentration in natural gas (62.5 ng NL −1) given by Xu et al (2015). The values measured do, however, approach the value, which according to these authors may already cause problems with machinery such as blocked valves, namely 0.01–63.0 pg NL −1 .…”

“…Moreover, some authors have presented evidence that volatile As species in natural gas may cause problems in technical appliances. Xu et al (2015) mentioned an international safety standard for the As concentration in natural gas of 62.5 ng NL −1 , as higher levels presumably already pose a threat to machinery. Delgado-Morales et al (1994) described blocked valves and pipelines in a New Mexican gas field caused by the formation of solid As compounds, later identified as tri- and dialkyl arsine sulfides, while others reported on catalyst failure due to As poisoning (Merryfield et al 1985).…”

Arsenic release to the environment from hydrocarbon production, storage, transportation, use and waste management

“…There are several approaches for separation, which often include use of solvents, hot water extractions (Jacobs and Filby, 1983) or acid digestions (Bicalho et al, 2017). Extracting volatile As species from natural gas is particularly challenging (Puri and Irgolic, 1989;Delgado-Morales et al, 1994b;Krupp et al, 2007;Xu et al, 2015;Cachia et al, 2017). Extraction methods include use of adsorption tubes or solutions (silver nitrate or nitric acid) to take up the volatile species such as trimethylarsine (TMA) from natural gas prior to analysis.…”

“…Most papers on methods focus on analyzing As in specific hydrocarbon sources, such as crude oil (Puri and Irgolic, 1989;Hardaway et al, 2004;Sánchez et al, 2013), oil sands (Bicalho et al, 2017), gasoline, diesel and naphtha (Brandão et al, 2006), and natural gas (Irgolic et al, 1991;Delgado-Morales et al, 1994b;Krupp et al, 2007;Xu et al, 2015;Cachia et al, 2017;Freije-Carrelo et al, 2017). As there are dozens of papers on analysis of As species in different hydrocarbon products, the reader is directed to these papers in addition to reviews (e. g., Nadkarni, 1991;Cassella et al, 2002;Sánchez et al, 2013) for more information.…”

Instrumental Setup for Simultaneous Total and Speciation Analysis of Volatile Arsenic Compounds in Gas and Liquefied Gas Samples

“…Methods for total As analysis are usually based on collection of the sample in different filters or solvents, such as mixed-cellulose ester filter or acid solutions. , Indirect methods are also often employed for total analysis of other metalloids or metals. For example, ISO 6978–1:2003 and ISO 6978–2:2003 methods for total analysis of mercury in natural gas require the use of chemisorption on iodine impregnated silica gel or collection on supported gold sorbent, respectively.…”