Integrated Multi-pollutant Control | Non-Thermal Plasma

Non-Thermal Plasma Technology for Multi-Pollutant Control

What is Non-Thermal Plasma?
Non-thermal plasma is a low energy discharge state of gaseous molecules. Its energy intensity is low so that the temperatures of the molecules and their excited species do not increase, however the excited radicals and ions may undergo chemical reactions. In emission control applications, pollutants are converted to harmless/useful chemicals.

Non-thermal Plasma Technology at CanmetENERGY
At CanmetENERGY we are developing non-thermal plasma technology using Plasma Corona Radical Shower (PCRS) to control multiple pollutants, namely SO2, NOx and Hg, from stationary combustion sources. By economic evaluation, this technology is far less expensive than controlling multiple pollutants with a suite of conventional pollution reduction technologies such as wet scrubbers and selective catalytic reduction (SCR).
Currently, most of the plasma technologies being developed employ wire-cylinder discharge geometry and an ammonia (NH3) reagent introduced into the flue gases. The reduction of SO2, NOx and Hg pollutant species can be over 90%, and the electrical consumption of the technology can be as high as 3% of the power plant’s production capacity. PCRS is a newer non-thermal plasma technology that employs a different geometric configuration in the reaction chamber, along with better control of the NH3 injection. In this process, ammonia is fed into the reaction chamber through hollow electrodes, resulting in higher NH3 concentrations within the plasma corona. Initial testing of PCRS shows promise of improved plasma performance with substantially reduced electricity consumption (<1% of production capacity).

We aim to develop the laboratory-scale PCRS technology into robust and economically optimized industrial solutions for controlling SO2, NOx, and Hg emissions. Our focus is to obtain the most relevant data possible to address practical concerns of industrial users. We have built a fully-customized test facility to simulate industrial flue conditions at an economical scale (coal combustion producing flue gas at a rate of 53 m3/h). The PCRS test facility includes a gravimetric pulverized coal feeder, 150,000 Btu/hr pulverized coal-fired furnace, air heaters, bag house, heat-exchanger, plasma reactor and a high efficiency electrostatic precipitator.

The PCRS test facility is primarily used to investigate the effects of variations in:

• Fuel characteristics
• Furnace operating parameters
• Emissions measurement (PM, SO2, NOx, Hg)
• Flue gas properties and composition
• PCRS operating parameters (reagent concentrations, voltage levels and profiles, electrode geometry, rapping sequences)

In the course of this work we have developed more efficient electrodes with star-shaped discharge elements and preliminary results showed that over 95% of SO2 can be removed from the flue gas.
Non-thermal Plasma Consortium
CanmetENERGY is forming a consortium with industry, government and academic partners to ensure that the resultant technology develops in a way that is optimized for industrial applications and maximum environmental benefit. Consortium members will have input into the testing process and design in order to address individual application issues. The consortium will also enable members to share and benefit from considerable expertise across sectors.