First Oxygen Concentration Control System for Ifrit Once-Through Boilers

Sep. 29, 2009

First Oxygen Concentration Control System for Ifrit Once-Through Boilers

Tokyo, September 29, 2009 — Kawasaki Thermal Engineering Co., Ltd. today announced the launch of the industry’s first system that controls oxygen concentrations in once-through boiler emissions. The system will be sold as an option on Kawasaki’s Ifrit line of large gas-fired once-through boilers starting in September.

The large-size Ifrit once-through boilers feature:
(1) superior control systems equivalent to those for large-size boilers generating high quality vapor.
(2) outstanding efficiency and a compact design.
Since its launch in 2000, the Ifrit series of boilers’ unrivalled steam pressure stability, high efficiency and quick start-up capability have made it the perfect solution for everything from industrial heating to cogeneration back up systems.

Equipped with an oxygen sensor, the system constantly monitors the oxygen concentration in exhaust emissions and controls the amount of air used for combustion. This new sensor enables the system to automatically maintain an optimal air-fuel ratio relevant to outdoor ambient temperatures. Conventional oxygen sensors are unable to provide optimal control of oxygen concentrations since their response is too slow for the once-through boiler’s quick start-up and excellent capacity to adapt to pressure changes. These deficiencies were stumbling blocks to applying an oxygen concentration control system to once-through boilers. Kawasaki’s use of a quick-response oxygen sensor and the development of a predictive control technique to respond to boiler load variations is a major breakthrough in once-through boiler technology. The new oxygen sensor boasts a sensor degradation diagnosis function that automatically adjusts sensor accuracy to eliminate the need for sensor calibration and cut maintenance costs. The new system will enable Ifrit users to save approximately 300,000 yen annually in fuel costs and reduce CO2 emissions by about 5.5 tons below pre-installation levels.*1

Revisions to Japan’s energy conservation law in 2008 make regular adjustment and recording of air-fuel ratio a requirement for small once-through boilers which had been previously exempt from the law. Kawasaki will aggressively market the new system as a solution that eliminates the need for regular manual adjustment of air-fuel ratios.

Working against a backdrop of growing environmental concerns, Kawasaki has made significant progress in boosting both the environmental performance and energy efficiency of Ifrit boilers. Kawasaki is hard at work protecting the environment via the development and sales of systems and equipment with superior energy efficiency and environmental performance in response to market needs.

*1. Based on calculations for model number IF-6000AGE (rated evaporation 6 t/h), operating 7,200 hours/year with an average load factor of 60% at a fuel cost of 100 yen/m3 N and 1.5% difference in oxygen concentration.