Remote Gas Flow Monitoring in a BioDigester

CLEVELAND - Aug. 2, 2021 - PRLog -- Compact Data Logger Aids Wastewater Treatment Company

CAS supplied the remote gas flow monitoring data logging solution for a wastewater treatment company looking to optimize its operation. In the natural gas industry, it's a well-established technique to produce biogas by aerobic or anaerobic "digestion," starting from various biodegradable materials. The gas obtained this way consists of 60-70% methane, and can be used to fuel the digester's boiler and electric generator engines.

The plant's Utilities Director decided that the ideal way to increase yields was to monitor and record the biodigester's gas flow. For example, immediately after feeding the digester, there was usually a strong momentary increase in gas production, but there were also seasonal variations since cold temperatures inhibit production.

Installation

The installed monitoring system consists of an industrial data logger connected to two gas flow meter sensors. The key factors are the installation environment and the properties of the gas to be measured.

1. A compact, self-contained weatherproof logger was required due to the need to be able to deploy it outside. The loggers needed to have an internal battery for power since AC power was not readily available at the site. It also needed to have cellular communications capability since neither Ethernet nor WiFi was available. For this project, the dataTaker DT90L was chosen because it offered an IP67 rated enclosure and operated over a temperature range of -40 to +70C.

2. The gases were mainly composed of methane and carbon dioxide (CO2), but hydrogen sulfide (H2S) and wet vapor were also present. Since these can have corrosive effects, technicians had to use specific gas flow sensors: in this case, two BFM mass flow meters. The flow meters were connected to the DT90's 4-20 mA analog inputs. One monitored the digester output and another measured the methane used by the boiler. Each flow meter had two 4-20 mA outputs: one for the gas flow and another for the temperature.

Standalone Operation and AlarmTransmission

This data logger, housed in a rugged 160 x 100 x 80 mm powder-coated aluminum enclosure, has a powerful 32-bit CPU with 16 MB of non-volatile storage for up to 500,000 measurements that provides for extended autonomous data logging capability.

Benefits

The DT90L data logger has both the necessary durability and a small footprint for this deployment. With eight channels and the internal 4G modem, it's a cost-effective device. The rugged, weatherproof construction plus the internal battery allow it to be deployed in a harsh, remote environment. Meanwhile, the Cloud service enables remote monitoring and mimic generation.

For more information on the dataTaker DT90L, or to find the ideal solution for your application-specific needs, contact a CAS DataLogger Application Specialist at (800) 956-4437 or visit us at https://www.dataloggerinc.com

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