PID controllers integrated in the adsorption air purification processes

2850T multifunction controller performs Multiloop PID control, encrypted Data recording of critical process values, plant interlocks and sequences. It also provides remote access to the control system and to the recorded data in protected environment

The air purification process with activated carbon is called adsorption and is based on the properties of activated carbon to treat most of the Volatile Organic Compounds –V.O.C.

Activated carbon filters / absorbers are also used to protect air quality, for example, in the sectors: of removal / recovery of solvents or solvent mixtures (e.g. VOC emission from painting),

The process involves two distinct cycles:

Filtration:  In this stage, the activated carbon, containing the pollutant to be absorbed, is passed through by the gaseous fluid.

Regeneration: Here filters are cleaned and dried using steam and air.

The steam is generated by an afterburner, fed with stripped VOC solvents, in this way the complete purification process has a limited energy consumption.

• These plants are subject to checks by the pollution authority about gas emissions in atmosphere.
• The value of the continues gas emission monitored by a gas analyzer has to be recorded and archived.

For the control of the plant, should be considered the 3 main phases which needs to be activated automatically or manually:

• Filtration: for about 5 days (40 hours) operations
• Regeneration of filters: about 5 hours
• Filters drying: about 30 minutes

At the end of the drying phase, the plant is ready for a new cycle

Few PID control loops required (Figure 1) :

• Flow of gaseous fluid with VOC for crossing the activated carbon filter
• Boiler temperature for steam generation
• Water tank Level for steam generation
• Steam Flow in the filters

Require remote access to the control system for service and monitoring purpose

Multifunction PID controllers 2850T

Core functions required for the application

• Precise and pre-configured multiloop loop PID control
• Logic interlocks and Math functions
• Custom graphic interface
• Data monitoring and encrypted recording (Archiving)
• Graphic display, process mimics, local visualization and operator interface
• Menu driven configurator tool
• Quick set up and easy configuration to suit the application
• Ethernet VNC Remote access

The Multifunction 2850T controller proved to be the perfect fit for the purpose, combining the functions of PID controller, process variable recorder and the capability to perform logical sequences.

In this application, the 2850T is configured to perform the following:

• 4 nos of PID Control loops with analog and valve positioned output
• Auto–Manual bump less transfer
• Management of the process alarms
• 15 sensitive variables are monitored and archived (smoke temperatures, flow rates, operating hours, etc.) to declare and evaluate the quality of the fumes discharged into the atmosphere
• The export of archived data, in historical files in encrypted format which guarantees the integrity of the information saved during various purification cycles. (Figure 2)
• Logic control (Figure 3) to perform the start of the regeneration cycle either automatically (as per a daily or weekly production schedule) or manually depending on the amount of treated product is combined with the safety and plant shut down sequences
• The Ethernet base VNC connection (Figure 4) enable remote access to the 2850T for maintenance purpose and remote monitoring and recording of the data