““The 6th International Exhibition on Industrial Furnace, Thermal Technology, Equipment and Material” (organized quadrennially by Japan Industrial Furnace Manufacturers Association) of THERMOTEC 2013 was held in Tokyo from July 3 to 5, having 18,955 visitors for the three consecutive days (as reported by the organizer). A total of 198 (180 domestic and 18 overseas) participants exhibited in Japan’s only exhibition of industrial furnace and related equipment and largest in Asia. The number of participants from seven countries was record-high according to the organizer.

With regard to the exhibits related to industrial gases, the keenest attention was paid by visitors to the development of O2-enriched combustion technology for commercial use.

Tokyo Gas pointed out the characteristic advantage of the oxygen combustion causing less waste gas as oxygen concentration rises in burning air, resulting in higher energy-saving effects. The practical features include (i) waste gas is reduced to about one fourth owing to less or no nitrogen by O2 combustion; (ii) the combustion effect is enhanced with less heat taken by nitrogen; (iii) nitrogen causing NOx has been eliminated; and (iv) an extremely hot flame (about 2800℃) can be obtained easily.

In practical calculation with an exhaust gas temperature of 1000℃ for example, the waste gas loss in the combustion of pure oxygen proved to be 17% with the consumed fuel of 61.3% bringing an energy-saving effect of 38.7%, in comparison with the waste gas loss of 49.1% in the usual air combustion with the fuel consumption of 100%.　Furthermore, they introduced a high-efficiency oxygen generator HT-PSA as a part of technology to reduce oxygen production cost.

While a conventional oxygen PSA uses zeolite which absorbs nitrogen, it is a distinguishing point that HT-PSA employs an absorbent of Perovskite-type oxide which has higher selectivity than zeolite, absorbing only oxygen, according to the industrial energy technology group of Energy Solution Division of Tokyo Gas).

By means of pressure reduction with a vacuum pump, they say we can generate oxygen of higher concentration than 95% which has been impossible with the conventional PSA method.

In addition, as nitrogen-enriched gas is taken out at the same time, a dual production of oxygen-enriched and nitrogen-enriched gases turns out to be possible. It brings about another feature that the power consumption rate to produce oxygen is reduced to about half of the conventional PSA (0.2kWh/m3N), resulting in low-cost production of oxygen.

The development of the said equipment which is part of the project adopted as NEDO’s Innovative energy-saving technology development is now being carried out by Tokyo Gas in collaboration jointly with Kyuchaku Gijutsu Kogyo, the Miura Laboratory of KASTEC and JNC Engineering. A pilot-scale machine for O2 generation of 5m3N/H will be manufactured within this year, and medium and small machines will be put into market in 2016. Their ultimate plan is to respond to a large-scale demand for an O2 generation of 10,000m3N/h class.”