ECD CA900 Sulfide Analyser
Oil and gas engineers tasked with accurately measuring hydrogen sulfide (H2S) levels in both production and refining operations will want to know more about the all-in-one CA900 Sulfide Analyser from Electro-Chemical Devices (ECD).
The ECD CA900 Sulfide Analyser is an all-in-one analyzer for the continuous measurement of sulfide ions in aqueous media, which are typically encountered at drilling production sites and in refinery operations, as well as in chemical plants. Other applications include municipal drinking water and wastewater effluent treatment, pulp/paper plants and tanneries.
The feature of ECD’s design is its reagent consumption, which has been minimized. With a focus on efficiency, the CA900 Sulfide Analyzer requires less than 7-8 litres per month providing ten samples per hour, or the same quantity will last five months at two samples per hour. By setting the analysis cycle, Users save on reagent cost and disposal fees while also minimizing technician labor time and maintaining timely measurements.
The science of Hydrogen sulfide gas is interesting. It dissolves in water and gives it that “rotten egg” odor. It exists in acidic water as a dissolved gas, at values above 7pH, Bisulfide ions (HS) are the predominant form of sulfide. At very high pH values (> pH 13), sulfide ions (S-2) are present and measurable.
The ECD CA900 uses an advanced, reliable sulfide ion selective electrode (ISE) sensing technology to measure the total amount of sulfide present in the sample. This measurement must be made at the high pH levels where S-2 is present. In order to achieve this high level of S-2, potassium hydroxide (KOH) is added to raise the sample level to around pH 13 (a pH electrode measures the actual pH level).
Sulfide and bisulfide co-exist in a pH dependent equilibrium with the ratio of each dependent on the pH. The sulfide ISE sensor measures the sulfide present in the sample and the pH measurement infers what percentage the sulfide represents. The analyzer then calculates and displays the total sulfide present.
The resulting highly caustic sample, is then neutralized with HCl, and the pH is measured and displayed to verify the neutralization. The neutralization of KOH is accomplished with HCl and produces potassium chloride (KCl) salt and water. Through this neutralization, the sample can be disposed of as waste or returned to the water supply.
ECD’s CA900 Sulfide Analyzer measures S-2 over a wide range from: 0.02 to 500 mg/l (0.02 to 500 ppm) over a temperature range of -5 to 50°C. The sample cycle rate is user changeable with a minimum cycle rate of 6 minutes per cycle time. The analyzer’s full-featured design also comes with four 4-20 analog outputs and four configurable relays (SPDT 15A 250VAC).
The CA900 Sulfide Analyzer is easy to start up and maintain. First connect the sample feed line, reagent lines and drain line to the analyzer. Mount both the sensors (S-2 and pH) in the flow cell. Next connect the two outputs (representing Total Sulfide and pH), and supply switched 110/220 VAC line power. Prime the peristaltic pumps and start the measurement cycle.
An integral touch screen display and 4-20 mA outputs, the S-2 Analyzer will indicate the total sulfide and the neutralized pH value. A digital display indicates the S-2 measurement, holding them until the next measurement cycle. The same sample and hold applies to the 4-20 mA output values that are captured during the measurement cycle.
With a user-friendly menu structure and touchscreen interface users can easily access information or customizing analysis routines. The CA900 Analyser can be web-enabled as a powerful internet of things (IoT) tool for remote in-plant monitoring and interfacing with personal handheld devices such as controllers, mobile phones, tablets, laptops and computers.
The CA900 line of Analsyers from ECD also includes Fluoride and Alkalinity. All the CA900 range analysers are built from the same base chassis and with ECD water Expertise and design sophistication.
For further information contact Peter Sims peter.s@ams-ic.com.au peter.s@ams-ic.com.au at AMS Instrumentation & Calibration Pty Ltd Head Office