“Since the incident at the Fukushima #1 Nuclear Power Plant broke out as a result of the Great East Japan Earthquake, what has become the mainstay power generation system is the thermal power plant. Thermal power plants which had been dormant were put back into operation, while plans for expansion have appeared everywhere. Corresponding to this, the demand for gas for use at thermal power plants is on the increase. Fewer types and a smaller amount of gas are used per facility compared to nuclear power plants. This is, however, an area which is attracting note by virtue of the fact that in a slump it is one of the few investment areas for industrial gas suppliers.

There are about 150 thermal power plants now in operation nationwide. Looking at the ratio of power output based on the fuel used shows that thermal power stations using LNG account for 54%, those using coal 27%, and those using oil 19%. LNG is the main type.

What gases are used by thermal power plants now in operation? For fuel the types of gas remain the same. The one used the most is ammonia for denitration. This could be said to be the gas most used at thermal power stations. LNG is a cleaner energy than coal or oil, and certainly there is no sulfur and smoke dust contained at all. During combustion, however, there is a reaction with the nitrogen in the air, resulting in the generation of nitrogen oxide (NOx), referred to as thermal NOx. This thermal NOx and ammonia (NH2) are made to undergo a reduction reaction, and are changed into nitrogen (N2) and water (H2O).

The amount of ammonia consumed at a 600,000 kW class power station is estimated to be 3.6 tons a day. The amount of ammonia in Japan put out for external sale on the market amounts to about 350,000 tons (2011 FY). Out of this about 60% is for denitration which comes out to around 210,000 tons. The amount used at thermal power stations comes out of this amount.

Because hydrogen is used to cool the heat generated in power generators, it can be used with all power generation systems, whether they be thermal or nuclear. The means of cooling the stator coil with hydrogen is known as “indirect hydrogen cooling.” “Water cooling” is also known as another method for cooling with water but hydrogen.

Surprisingly, carbon dioxide is also used. A power station needs an open inspection according to the time operated, or at least once ever 2 years. At these times the hydrogen is pushed out and cleared from the generator with carbon dioxide. No other gas is characterized by being inert and with a high specific weight than carbon dioxide. Although it is not used normally, the amount used each time is estimated to come to 500-1,000 kg.

Nitrogen is used for various applications such as for emergency purging and for preventing explosions. It appears that the supply method with a bundle of cylinders is used more because pressurization is required when used in emergencies. Nitrogen PSA is also used. Around 10,000 m3 is used a month but whether or not there is purging the amount used fluctuates greatly.

There are 21 thermal power plants already under construction. There are also a total of 16 getting ready for construction or planned. Vigorous investment is being made to secure a stable supply of electricity.

What is of note is that not only is the power generation capacity being expanded, but that also there is a tendency to bring the combined cycle system into LNG-fired thermal power generation to raise power generation efficiency. In contrast to Integrated Gasification Combined Cycle (IGCC), it appears that oxygen is not used but there is the potential that this will lead to use of nitrogen. Of course an increase is anticipated in the use of ammonia, carbon dioxide, and hydrogen.

When it comes to capital investment too, this means that an expansion in the demand for gas is expected for use at construction sites and at manufacturers of power generators. A special demand for gas is developing for use at thermal power stations.”