A case history from Toray Fine Chemicals (TFC) in Chiba, Japan demonstrates how the company has added wireless pressure gauges for continuous monitoring of blower discharge pressure and achieved very notable cost savings and safety improvements. These steps can be emulated in many applications where blowers are used.
TFC produces DMSO (dimethyl sulfoxide) and polysulfide polymer, and also produces acrylic polymer. At TFC, wastewater discharged from factory manufacturing processes is biologically treated at the wastewater treatment process plant before being sent to public bodies of water. A typical blower used in a wastewater treatment process is an aeration blower that sends oxygen into the aeration tank. At TFC, six blowers are also used for biological treatment equipment other than general aeration tanks.
The operation state of the six blowers is monitored continuously by using the signal (ON/OFF) from the operation circuit, which is detected by the monitoring system. Like aeration blowers, if these blowers are stopped the supply of oxygen is stopped and the processing of waste liquid sludge becomes anaerobic, generating toxic hydrogen sulfide and phosphorous. Therefore, when the blower stops abnormally due to some cause, it is critical to restore oxygen supply immediately to avoid toxic releases.
Malfunction of the aeration blower can be determined early by operation monitoring of the pump and trend management of dissolved oxygen in the aeration tank. However, for the six blowers of this biological treatment facility, it was difficult to detect malfunction as the blowers could only be monitored through manual rounds.
The company considered various continuous monitoring methods. Monitoring of load current requires significant rework such as adding new measurement equipment into the existing control panel and other related installations to send output back to the operator station. Monitoring of blower discharge flow rate requires large-scale construction work to install a flow meter for the discharge piping with large diameter. On the other hand, continuous monitoring of the discharge pressure of the blowers using the existing process connection of pressure gauges was a viable option.
TFC installed Rosemount™ Wireless Pressure Gauges (WPGs), replacing the existing mechanical pressure gauges to measure the discharge pressure of the blowers. Previously, it was difficult to detect malfunction as it was just the ON/OFF status monitoring of the blower or by periodic manual rounds to visually inspect for any detached or breakage of belts. With the addition of WPGs, the discharge pressure was continuously monitored at the operator station with minimal manual rounds and early detection of blower malfunctioning.
With continuous monitoring and trending of blower discharge pressure, TFC is now able to prevent the generation of toxic gas by early detection of blower malfunctioning which would impact the supply of oxygen to the biological treatment facility. Blower discharge pressure trending can also be used to detect and confirm membrane clogging issues.
Through the choice of wireless, the total instrument and installation costs were reduced by approximately 50 percent when compared to analog/wired instrumentation. There was no additional mechanical gauge needed for field checks. And, there were no more mechanical gauge failures due to high vibration of the blower, hence the measurement was reliable and maintenance-free. TFC estimates savings of ¥450,000 yen ($3,957 USD)/day per single blower failure.
Do you use blowers in your application? Would wireless pressure gauges work better for you?