Convection region sootblowing optimisation
is achieved by adding a device for real-time furnace exit
gas temperature (FEGT) measurement, measuring existing plant
parameters related to heat transfer distribution, then initiating
sootblower operations based on section by section heat transfer
surface cleanliness factors. Cleanliness factors (CF's)
are used to provide the input for sootblowing optimisation.
CF¹s are defined as the ratio of the section's actual heat
transfer coefficient to the heat transfer coefficient that
would occur if the section were 100% clean. The cleanliness
factors for heat transfer sections, such as the economizer
and reheater, are determined based on plant information
and calculations performed on the sootblower control system
platform.
The required plant information
is read from the station PLC/DCS OR LAN communication highway.
The plant provides signals on the PLC/DCS OR LAN communication
highway for each heat transfer section and for selected
overall plant operating conditions. For each section where
a cleanliness factor is desired, the fluid-side cold and
hot temperatures are required. The overall plant conditions
required include load, excess oxygen level, feedwater flow,
spray flows, coal mass rate (or CEM volumetric gas flow),
and economiser gas outlet temperature.
The following illustration shows
a sample display from the Boiler Cleaning Management System:
click to enlarge
Furnace exit gas temperature is
measured using SpectraTemp™.This is an optical-based
temperature measurement device that allows it to be used
from start-up to full load.
BMS/ASI currently have over 75
Boiler Cleaning Management Systems installed in the USA,
UK and Germany.
The financial and operational improvements
that have been achieved by these systems have resulted in
attractive pay back periods.
Some customers have found that
by using the system they have been able to run continuously
at full load whereas previously this has been impossible
due to operational constraints.
