Watanabe Laboratory

TEL : 022-795-7384
MAIL : noriaki.watanabe.e6@tohoku.ac.jp

Environmental and Energy Engineering, Department of Mechanical and Aerospace Engineering, School of Engineering
Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies
We conducted various research in energy resources, environmental sciences, and engineering. They include environmental risk
assessments, geosciences and geoengineering in light of energy resource production, and geo-informatics for a sustainable future.
Recently, our work has focused on the sustainable and profitable production of petroleum and geothermal energy, as well as CO2
sequestration and mineralization.

Domestic and international conferences

Various joyful events

Carbon Recycle CO2 Geothermal Power GenerationExperiment System

New fracturing method combining CO2 & water injection
CO2Water

Multidirectional fracturing of rock using shear thickening fluid

CO2&Water

Hydraulic fracturing
Fracture nucleation improves thepermeability only in a certain direction.
How does the fracturing manner changeby the shear thickening fluid (STF)?

(Wu et al., 2020，Int. J. Hydrogen Energy)High flow rate and narrow fracture width
Increase in viscosity
CO2 & water fracturing
mechanism

pore water in rocks inhibits
fractures opening and propagation

We have produced multidirectional
fractures and larger aperture fractures,
which improve rock permeability.

• Is it effective in thepresence of pore water?
• Does it work on porous
volcanic rocks?

open and propagate
the fracture(SiO₂ + Ethylene glycol)

Possible mechanism of STF fracturing

andesitic lapilli tuff
Water SaturatedDry

水pressurize
CO2

CO2
fracture formation

CO2 & water fracturing is still effective with thepre-existing pore water and is particularly
effective in porous volcanic rocks.

GraniteEnhanced CO2 geological storage and mineralization
using biodegradable chelating agents
CCS, in which CO2 is injected into underground rocks and fixed as acarbonate mineral, has been attracting attention in recent years.
𝑪𝒂𝟐+ + 𝑪𝑶𝟑 𝟐− = 𝑪𝒂𝑪𝑶𝟑← Carbonate
minerals

Pore→

In order to utilize reservoirs in the mostefficient, safe, and secure manner,
we invented a method to promote CO2
geological storage and mineral fixation.
[patent application2023-51335]

Chelatingagent injector
into rock 。

BeforeModeling of accelerated mineral dissolution forenhanced CO2 geological storage and mineralization using
biodegradable chelating agents
Challenges of CO2 geological storage and mineralization in basaltic rocks:
Porosity, pore connectivity, permeability and reactivity of basalts are not always high enoughNew approach for enhanced CO2 geological storage and mineralization

After

What is the applicability to basaltic volcanic sandstone containing clay minerals?

Challenge: Clay minerals clogging channels and poor permeability
1st step:
accelerated mineral dissolution modelingRocks that have undergone clayey alterationand oxidative alteration
Contains the clay mineral montmorilloniteBiodegradable chelating agent GLDA
dissolves minerals to improve permeability

Montmorillonite dissolved in GLDA
Confirmation of pore formation

Solution of GLDA with high concentration of NaHCO3CO2 gas
Ca-GLDA ❷GLDA ❸
CO2 capture andNaHCO3 Ca carbonation Na+

room temperature
pH 8pH adjustinghigher temperature(<100 C)

residual solids

room temperature
pH 8

CaCO3

CCUS 【Carbon dioxide Capture, Utilizationand Storage】 → CO2 mineralization
CO2 mineralization assisted by chelating agents· Low cost: industrial waste utilization, chelating
agent recycling, low to moderate temperature· High returns: valuable products (e.g., CaCO3)· Environmentally friendly: without wastewater❶ Minerals dissolution enhanced in chelating
agents even at neutral to alkaline conditions
e.g., 45 g CO2 /1 kg fly ash(GLDA-Na4)❷ Morphologies of CaCO3 can be controlled❶ Ca extraction
CaSiO3 + H2-GLDA2– +2H+ → Ca-GLDA2– + H4SiO4❷ Ca carbonation
Ca-GLDA2− + HCO3- + H+ → CaCO3 ↓ + H2-GLDA2−❸ pH recovery CO2 capture
CO2 + H2O → H+ + HCO3-❶+❷+❸

Mg 2+ + OH −Complexformation

𝑹 = 𝑲([𝐗]𝐭𝐨𝐭𝐚𝐥,𝐬𝐚𝐭 − 𝐗 𝐭𝐨𝐭𝐚𝐥 )Dissolution is driven by the difference in concentration

MgOH +CaSiO3 + CO2 + H2O → CaCO3 + H4SiO4Aragonite (CaCO3)

GLDA

MgY 2−

Long-term mineraldissolution modelling ispossible!

A T-swing process for enhanced CO2 capture and storage
using recyclable chelating agent

Ca extraction

Y: GLDAMg 2+ + Y 4−

Aids in thedissolution ofminerals!

❶Mg：

4Mg 2+ + 4OH −Mg 4 (OH)4 2−

Permeability UP！

Ca-basedindustrial waste

Kinetics

Equilibrium

water100 h