Increasingly stringent air quality requirements have led to expanded use of wet scrubber systems to control air emissions. Chlorine storage facilities and chemical process plants are frequently required to scrub exhaust gas streams to remove halogen and acid gases.  Unfortunately, monitoring reactive gas concentrations in moisture saturated air streams presents problems for standard diffusion sensors. Condensing water in these air lines can quickly blind diffusion sensors, rendering them inoperable.

ATI’s Series B12 Wet Gas System was developed to meet the need for reliable measurements in wet scrubber outlets for other gas streams that might be saturated with water vapor. Systems have been developed for monitoring strong oxidants (chlorine, bromine, chlorine dioxide, or ozone), acid gases (HCl or HF), and hydrogen.

The basic B12 Wet Gas System consists of a loop-powered 2-wire transmitter and a corrosion resistant sensor specifically engineered to operate at 100% RH. Sensors are designed for direct insertion into vent stacks, or may be used in a flowcell if sample can be pumped to the sensor.  When remote display and alarm relay functions are required, the B12 Wet Gas Transmitters can be connected to ATI's B14 Alarm Receiver System. This system will provide direct digital display of gas concentration, plus 3 alarm setpoints, remote alarm reset input, and retransmitted 4-20 mA output. Or, the B12 transmitter may be used separately and tied directly to the users' DCS, PLC, or other equipment. Either way, the B12 is an excellent solution to a difficult monitoring problem.

The Gas Transmitter for the detection of ________ (Specify Gas) shall be provided to monitor the gas concentration in wet 100% moisture saturated atmosphere in the __________ (Specify Location). Each gas transmitter shall be housed in a NEMA 4X enclosure and available with an optional LCD display to indicate either PPM or % gas. An explosion proof transmitter enclosure can be provided for hazardous locations. The transmitter shall provide a 4-20 mA analog signal proportional to the gas range and be loop powered, 12 to 28 VDC.

The sensor shall be designed for either direct insertion into a vent stack or for use in a flowcell where sample pumping may be required. The sensor shall connect to the transmitter via a 25 foot 5-conductor cable with quick disconnect connector. The sensor shall be electrochemical, polarographic with a special membrane to isolate the electrodes from the gas stream and allow gas to diffuse into the sensor resulting in a reaction between the electrodes and resulting in signal to be amplified by the transmitter. A precision RTD shall continuously compensate for effects of temperature and provide a feedback signal to the transmitter circuit.

Optional associated equipment:

Model B14 Receiver and alarm module (see specification sheet TS/B14)

Model A21 Gas Sample Pumping System (see specification TS/A21)