We started researching the CN lime firing process to contribute further to carbon neutrality (CN) in the field of lime shaft kilns, in which we have a high domestic share.

Lime shaft kilns, which produce quicklime that is mainly an auxiliary raw material for steelmaking, discharge CO₂ in the lime firing process. However, no measures for that have been established and this has been a big issue for operators who own lime shaft kilns.

This CN lime firing process recovers CO₂ in high concentration.

The concentration of CO₂ generated in a lime shaft kiln is approx. 20%, because it is diluted with combustion flue gas and oxygen/nitrogen in cooling air. In order to utilize recovered CO₂ effectively, its concentration needs to be increased. This process extracts cooling air out of the kiln before sending it to the thermal storage shaft, and uses oxygen instead of combustion air. This increases the flue gas concentration significantly to approx. 90% without using a large CO₂ separator.

We will establish this method within this fiscal year and we plan to study how to utilize recovered CO₂ jointly with outside institutions that have knowledge of advanced technologies, such as methanation and hydrogen utilization.

The Agency for Natural Resources and Energy has a subsidy program (*1) that recently adopted the small-sized lime handling parallel flow regenerative (PFR) kiln, which is a derivative product of our PFR kiln (*2), and this project joined the list of energy-saving best available technologies (BAT) to replace existing rotary kilns. This process can also be installed in this small-sized lime handling PFR kiln.

Under the banner of “Green & Smart” (green: technological innovation to promote decarbonization, smart: making products smart using the latest technology), Steel Plantech is developing and supplying products and services incorporating the latest technologies.

Regarding lime shaft kilns, the “green” part will be establishing this process while the “smart” part is already underway with the utilization of “Spco-CLOUD” of the Smart Products “S-Series” (*3) to analyze the operation data. In this way, we started activities to support more efficient operations.

Steel Plantech will further promote “Green & Smart” and continue to provide technologies that contribute to people, society, and environment, which are our corporate mission and managing principles.

*1: FY2022 Subsidies for the Support Program to Promote Investments in Advanced Energy Conservation
With the goal of achieving carbon neutrality in 2050, the Agency for Natural Resources and Energy identifies advanced technologies with high energy-saving potential from the market, and grants subsidies to them intensively. When a business operator installs equipment that is eligible for this program, they can receive the subsidy if they meet certain energy-saving requirements. Our lime shaft kiln was adopted as an advanced equipment/system in this program. (This public offering ended on Thursday, June 30, 2022.)

*2: Parallel flow regenerative (PFR) kiln
The parallel flow regenerative (PFR) kiln combines a parallel flow firing kiln and a regenerative kiln that recovers sensible heat of combustion flue gas and cooling air to ensure both stable product quality and high thermal efficiency at a high level.

*3: Smart Products “S-Series”
These are products that are being developed in response to customers’ needs, such as ensuring factory safety and saving labor using robots; improving operation and product quality by using images, AI, and big-data analyses; and providing operation support service based on process analysis.
As of July 2022, 19 products (such as Spco-CLOUD, Spco-ROBO KNIGHT, Spco-MOLD VIEW, and Spco-COUNT) have been placed in the market. We aim to centrally integrate operation rooms, which used to be installed at each plant, and make systems smarter, such as achieving remote operation and one-man operation.