Breakthrough measuring particles in high-temperature chimneys

Researchers at the Korea Institute of Machinery and Material (KIMM) have developed a technology to enable real-time measurement of PM10 and PM2.5 inside high-temperature environments such as power plants and incinerators. 

Acquiring data in real-time has hitherto been difficult because of the extreme conditions within chimneys, specifically high temperatures and dense particle concentrations.

The research team lead, by Dr. Bangwoo Han, head of the Department of Urban Environment Research at KIMM, were looking for a more efficient way of monitoring particles than the two prevalent methods: 

The light transmission method, in which quantities of Total Suspended Particles (TSP) are measured by assessing the reduction in light intensity after it passes through dust particles in the chimney, are best suited for the real-time measuring of particle concentration but are not particularly accurate as TSPs are typically anything that is 50 microns or less.

The gravimetric method, in which particle mass concentration is determined by weighing filters before and after a sampling period, is more accurate but takes too long to be considered ‘real-time’.

The KIMM team have developed a technology that transforms the harsh conditions inside chimneys into an ambient environment with room temperature and low particle concentration, enabling accurate measurement.

The team developed four distinct technologies which have enabled them to manage emissions from chimneys based on particle size (PM10 and PM2.5) rather than on the total suspended particles. These are:

Iso-kinetic inlet: This inlet decelerates the velocity of the exhaust gases entering the measurement device, enabling precise measurements of fine particles.

Constant sampling and dilution: The team has engineered an automatic control which ensures that a consistent volume of exhaust gas is sampled, regardless of variations such as pressure and temperature changes within the chimney.

Droplet separation: This avoids the formation of condensation droplets by keeping the temperature of the device sufficiently high.

Prevention of loss of particles on inner surfaces: This reduces particle adhesion loss by injecting air into a porous metal tube.

The effectiveness of this real-time fine particle monitoring approach has been confirmed during a six-month demonstration period at a number of domestic power plants and incinerators.

Dr. Bangwoo Han said: ‘We have developed a first-of-its-kind technology that allows for the accurate determination of both the concentration and size distribution of fine particles from chimneys in real time. Based on the concentration data of fine particles measured in the fields, we will strive to establish a comprehensive management system for fine particle emission sources.’