Air Water has been engaged from April in the producing verification of CO2-recycled green dry ice from waste gas (CO2 concentration of approx.10%) discharged from the woody biomass at Nihon Kaisui Ako Power Plant of the Air Water Group. Air Water realized to produce a dry ice of as good quality as the conventional product, accomplishing the target from the beginning. For the reason that the dry ice was produced from the gas discharged from woody biomass, it has an added value of “carbon neutral.”

Air Water is planning to go ahead toward industrialization including proposals for customer’s plants. To cope with the booming needs for recovery of low-purity CO2 such as from plant wastes, Air Water has developed a CO2 recycling device named “ReCO2 STATION.” It is expected to contribute to reducing emission of CO2 and also to make a new source of CO2 of local production and consumption.

In the “ReCO2 STATION,” as described in the chart, a set of facilities are housed compactly into a 40ft container from the intake of waste gas to the production of dry ice. Nanako Nishii in charge of the design and development of the equipment said, “No individual installation work is necessary saving the construction time as the necessary facilities are housed in the container. Furthermore, the scale (100 kg per day) of the demonstration model for verification to produce dry ice at this time corresponds to the production Equipment Class 2, which requires only notification to a prefectural office for operation. It means the hurdle for introduction is low.”

From a technological viewpoint, it is also a noticeable point that an efficient purification method of CO2 has been attained with less energy by the unique 2-stage PVSA in use of the adsorptive separation technology owned by the company. During the verification period taking about two months, they accumulated the data for an actual operation of equipment and produced a difficult dry ice pellet of 3 millimeter.

The pellets were really used for dry ice blast cleaning in the neighboring user’s plant, and proved that the products have the same quality and properties as those of the conventional products.

Regarding the development in the future, Air Water comments, “We are planning to install the model also in other plants to verify the product under different conditions of use.
We would like to promote actively the environmental value of the CO2 product from CO2 low-concentration waste gas, and develop our activities expanding the variation of output and concentration of CO2, so that we can meet user’s requirements. Especially, for such users as having a usage of dry ice in their own premises we wish to take advantage actively because one stop process can be possible from recycling to use of CO2 inside the premises.”