The importance of oxides of nitrogen (NOx) handling is ever increasing to address global environmental emission targets and regulations. For handling of NOx gases, our leading-edge technologies enable you to comply with all environmental standards worldwide.
KBR offers its proprietary PLINKE NOx absorption technology for maximum yields and lowest environmental emissions. Nitrous gases from vent streams are recovered as nitric acid in a highly efficient cooled-tray absorption tower without consumption of chemicals. This technology normally uses only water and atmospheric air. After treatment, effluent gases comply with all environmental standards for NOx worldwide.
“Our proprietary NOx absorption technology offers maximum yields and lowest environmental emissions.”
If other compounds beside NOx need to be treated, we cooperate with other companies to supply a full-scope solution to our clients. Our absorption technology is especially suitable for high NOx concentration and for offgas volume flows up to a few thousand normal cubic meters per hour.
High-Pressure NOx Absorption
A mixture of NOx containing gas and air is compressed to 6 barg (about 90 psig) using proven liquid ring compressors and fed into the absorption tower, which is equipped with special internals for high-efficiency cooling and mass transfer. KBR's proprietary PLINKE tray design minimizes tower volume, resulting in smaller plot plan and lower capital investment. NOx is recovered as nitric acid at about 50–60 wt% concentration. This technology can be applied on vent gases with high NOx content and strong environmental standards for the effluent gas. KBR has built such systems worldwide, both as stand-alone units and paired with PLINKE technology plants.
Medium-Pressure NOx Absorption
Similarly to the high-pressure system, NOx-containing gas and air are compressed using liquid ring compressors, but pressure is kept around 3–5 barg (about 45–75 psig). The absorption tower can be a tray tower, similar to the one used in the high-pressure system or a packed column. Because of the medium pressure, the absorption tower is larger than the one used in the high-pressure absorption process. This technology can be applied on vent gases with high NOx content and moderate environmental standards, and additional oxidizers may be used to achieve strong environmental standards.
Low-Pressure NOx Absorption
A mixture of NOx-containing gas and air is compressed to only 2 barg (about 30 psig) by standard blowers and fed into a packed column. Because of the low operating pressure, the absorption tower is larger than the high- and medium-pressure technologies. Usually oxidizers are used in order to achieve sufficient NOx removal. Preferred application is on vent gas with low NOx content and moderate environmental standards.
For gas streams with very low NOx content, the technologies above may not be economically viable. Caustic washing removes NOx as nitrates, which are subsequently treated in the waste water treatment facility.