Particle Size Analysers

Greenbank Terotech, in partnership with their Joint Venture R&D company GAIM Ltd, have developed the Greenbank StackMaster technology for on-line, non-intrusive measurement of particulate in stack flue gas. The technology has been developed from a need to measure particulate density and size distribution at any desired location in the stack real time. Measured parameters are the particle size distribution giving % particles in customer required size ranges and a particulate density expressed as mg/m3.

Greenbank StackMaster captures multiple images per second and rapidly determines the number of particles and the particle size distribution. Calibration is required for the specific set up location and densities to be used in calculations. The system rapidly calculates the mg/m3 from the number of particles measured, their size and the known volume of interrogation from the laser and CCD alignment. The particle size outputs as % and mg/m3 are outputted as 4-20mA. The system then repeats the process. A 4-20mA signal of MW load is taken from the plant so that the system shuts down when not in use.

The main benefits of the StackMaster are:

• Reduction in stack manual sampling costs and frequency
• Real time alarm for poor precipitator performance
• Identify poor milling / classification by adjusting mill loadings
• Include in any boiler optimisation strategy
• Allows future identification of particulate matter by size, such as PM10
• No need for constant recalibration of opacity monitors
• I/O and plant interface is via NI Field-point PLC controllers
• ISO-Kinetic
• No material handling
• Low maintenance with only 2 static optical devices located outside the stack

Laser System

The laser system is designed to comply with BS EN 60825-1 and BS EN 60101-1. All covers are interlocked, so that the laser cannot be run if any cover is removed. The laser comes with a solenoid driven safety shutter. All optical equipment is located physically outside the stack but can measure at almost any point along the diameter desired inside the stack. A pulsed laser beam is spread through a lens to give a pseudo sheet of laser light in the chimney.

Sensors / Optical Equipment

• Laser with optics fully enclosed for parallel beam laser sheet including mounting
• Laser generator / local control in IP65 cabinet
• Electrical interlocks for local ports of entry into the stack.
• Mounting and high resolution rapid CCD camera
• Optional industrial compressor fan for air cleaning curtain for optical equipment

Industrial Vision System & PLC Enclosure

• IP65 cabinet with LED indicators on cabinet for laser on / off
• Rapid control with trigger for synch with laser
• PLC type compact vision system for rapid analysis, complete with Greenbank StackMaster software.
• Power supplies and control for laser
• 4-20mA outputs for mg/m3 and particle size
• 4-20mA input for boiler load MW
• 110 VAC for control cabinet / laser control
• Optional 415 VAC 3 phase for local air compressor
• Better than BS6069 that applies to variance of dust