Linde Gases has announced that its innovative nitrogen oxides (NOx) emissions removal technology, LoTOx™, is now available for the power industry.

LoTOx (low temperature oxidation) is a highly cost effective alternative to selective catalytic reduction (SCR) technology and will be made available initially to US power companies through URS Corporation, Linde’s exclusive licensee for the power industry in North America.

NOx, mainly consisting of nitric oxide (NO) and nitrogen dioxide (NO2), is among the major pollutants listed under the Clean Air Act by the US Environmental Protection Agency (EPA) and is also rigorously monitored by the EU and China. NOx undergoes chemical and photochemical reactions in the atmosphere and reacts with volatile organic compounds (VOCs) in the presence of sunlight to form smog, acid rain and ground level ozone. The effect is significant, particularly in warm weather, and represents not only an environmental threat, but a considerable health hazard, especially to those with lung diseases.

NOx deriving from stationary combustion sources makes a major contribution to total global emissions and the largest output is from coal fired boilers, particularly those involved in power generation. In response, environmental authorities are tightening legislation governing NOx emissions, examples of which include the US EPA’s Clean Air Interstate Rule (CAIR) and Regional Haze and the EU’s Large Combustion Plant Regulations.

Technology for removal of high levels of NOx has primarily existed, until recently, in the form of either selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR).  Both technologies, however, have limitations. These include potential compromise of the catalyst when treating dirty gas steams, process disruption, plant shut-down or lower levels of performance in NOx removal.

LoTOx is a selective, low temperature oxidation technology, which works on “dirty” exhaust gas streams by injecting ozone into the flue gas to oxidise NOx into water soluble and reactive nitric pentoxide (N2O5), which can then safely be disposed of or sold as a valuable by-product.

The LoTOx process is applied just before or within the existing flue gas desulphurisation (FGD) scrubbing system, enabling the removal of NOx and other pollutants such as SOx, mercury, particulate matter and other acid gases, adding to its multi-pollutant control capabilities Additionally, as LoTOx is a post-combustion solution that treats the flue gas at the end of the customer’s process, it does not interfere with the combustion system, resulting in easier, less disruptive retrofits.

”LoTOx has already gained a reputation within other heavy combustion industries for delivering SCR-like performance while bypassing some of its limitations in relation to dirty flue gases,” said Steve Finley, Head of Environmental Solutions, Chemicals & Environment, Linde.

“It is also a cost effective alternative for power plants with high NOx removal requirements and highly flexible for handling more stringent regulations in the future –It is the only post combustion NOx control technology of its kind and we are delighted to make it available to the power industry.”