Capture – Separate and Recover – CO2

Development of chemical absorption technology

Process flow

Process flow

Chemical absorption is a technology to capture CO2 from blast furnace gas (BFG): an alkaline aqueous solution, or absorbent, such as amine, selectively absorbs CO2 when contacting blast furnace gas (BFG) containing CO2 in an absorption tower, and then the CO2-laden absorbent releases CO2 after heating in a regeneration tower.
Development of chemical absorption, though suitable for capturing large amount of CO2 from gases at ordinary pressure, has just been launched aiming at applying to steelmaking process, and several technical issues need to be solved. This project will address the following technical issues, incorporating an evaluation pilot plant with the capacity of approximately 30t-CO2/day into a real steelmaking plant:

  • Reduction of energy consumption – development of new absorbent solutions and effective utilization of energies from steelmaking processes.
  • Quantification of effects of CO2 capturing technologies on steelmaking processes

The developed absorbents have been commercialized for industrial application as by NIPPON STEEL ENGINEERING CO., LTD.; Energy-Saving CO2 Absorption Process (ESCAP™).

CO2 capture bench test plant (1t-CO2/d)

Development of novel chemical absorbents with the aid of experimental and computational methods

New chemical absorbents, by which a CO2 capture system can be operated with lower CO2 capture energy, are developed by means of joint experimental and computational methods such as quantum chemistry and statistical data processing.

1. Design new absorbents by computational chemistry

2. Synthesize new absorbents

Apparatus for gas – liquid equilibrium
Apparatus for absorption – diffusion measurement

3. Evaluate CO2 capture performance by experimental methods

Development of Physical Adsorption Technology

Physical adsorption method is a technology that can separate and recover carbon dioxide with low energy consumption, though requiring a simple system configuration. With the physical adsorption method, adsorbents, first of all, selectively adsorb CO2 with the help of the van der Waals force working between the molecules of fluid and the surface of the adsorbents, and then release the adsorbed CO2 under a reduced pressure, consequently allowing CO2 capture – separation and recovery – with high purity at high recovery rates. This is the first attempt in Japan to apply this technology to a processing on a very large scale, i.e., capture – separation and recovery – of CO2 from blast furnace gas.

* You can see the figure enlarged.

By selecting the most suitable CO2 adsorbent in the laboratory test, the target recovery rate was obtained.

* You can see the figure enlarged.

In this project, an evaluation plant with a capacity of 3 t-CO2/day was constructed in the steelworks. Efforts were made to further reduce energy consumption and to develop a scale-up process.

Bird’s-eye view drawing of bench test plant(ASCOA*-3)

*Advanced Separation system by Carbon Oxides Adsorption