Scholarly article on topic 'Numerical Analysis of Storage Potentials for CO2 Micro-bubble Storage (CMS)'

Numerical Analysis of Storage Potentials for CO2 Micro-bubble Storage (CMS) Academic research paper on "Earth and related environmental sciences"

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Abstract of research paper on Earth and related environmental sciences, author of scientific article — Takashi Hitomi, Takeshi Sasakura, Masayuki Yamaura, Masanori Tozawa, Masahiko Tagami, et al.

Abstract For geological storage, as the small-scale distributed emission systems, CO2 micro-bubble storage (CMS) system may be suitable. To validate the feasibility of the CMS system, a numerical analysis was carried out. For the injection method and the targeted depth defined above, a unit comprising an injection well and four water pumping wells was modeled, The study showed a possibility of stable storage of CO2 in solution under the conditions of temperature, pressure and water chemistry at depths of 300 to 500 m, as long as full dissolution of CO2 gas with micro-bubbles is ensured.

Academic research paper on topic "Numerical Analysis of Storage Potentials for CO2 Micro-bubble Storage (CMS)"

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Energy Procedia 37 (2013) 5970- 5977

GHGT-11

Numerical Analysis of Storage Potentials for CO2 Micro-bubble Storage (CMS)

Takashi Hitomi1*, Takeshi Sasakura2, Masayuki Yamaura3, Masanori Tozawa4 Masahiko Tagami5, Kenichiro Suzuki1, Hiroshi Wada6

1 Obayashi Corporation, 2-15-2, Kounan, Minato-ku, Tokyo, 108-8502, Japan

2 Kajima Corporation, 2-19-1, Tobitakyu, Chofu-shi, Tokyo, 182-0036, Japan)

3 Dia Consultants Co. Ltd., 1-7-4, Iwamoto-cho, Chiyoda-ku, Tokyo, Tokyo, 101-0032, Japan

4 Asano Taiseikiso Engineering Co. Ltd., 3-43-3, Sendagi. Bunkyo-ku, 113-0022, Tokyo, Japan

5 Kawasaki Geological Engineering Co. Ltd., 2-11-15, Mita, Minato-ku, Tokyo, 108-8337 Japan

6 Engineering Advancement Association of Japan (ENAA),3-18-29, Toranomon, Minato-ku, Tokyo,105-0001, Japan

Abstract

For geological storage, as the small-scale distributed emission systems, CO2 micro-bubble storage (CMS) system may be suitable. To validate the feasibility of the CMS system, a numerical analysis was carried out. For the injection method and the targeted depth defined above, a unit comprising an injection well and four water pumping wells was modeled, The study showed a possibility of stable storage of CO2 in solution under the conditions of temperature, pressure and water chemistry at depths of 300 to 500 m, as long as full dissolution of CO2 gas with micro-bubbles is ensured.

© 2013 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of GHGT

Keywords: CO2 storage, Numerical Analysis, Combined Injection System ;

1. Introduction

CCS (Carbon Dioxide Capture & Storage) is investigated as a measure against global warming. The

current standard concept of CCS is as follows: CO2 collected from effluent gas in the supercritical state is pressed into the lower retention layer of a stratum becoming the cover layer of depth greater than GL-800 m (the sand layer) and accumulated. However, separation, collection and transportation of CO2 is

expensive. In addition, it can easily rise to the surface again because of its high buoyancy in the super-

critical state. However, when it is dissolved in groundwater, the dissolution water becomes heavier than groundwater, so that the CO2 is isolated in a stable state underground. However, if CO2 is dissolved in water at the surface and then injected, it is very inefficient and requires a large quantity of water.[1]

1876-6102 © 2013 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of GHGT doi: 10.1016/j .egypro .2013.06.524

This report describes the following results. The characteristics of the microbubbles, which can be easily dissolved in groundwater, are used. An existing deep saltwater aquifer is considered as the retention layer. The feasibility retaining CO2 underground were estimated by numerical analysis of a model area were analyzed.

2. Study of CO2 behavior in groundwater

2.1. Control by combination method of infusion well and pumping well

The basic concept is a combined system of injection well and plural pumping wells placed planarly around a injection well. Fig. 1 shows a concept diagram.

Injection Well

Pumping Well

Storage Area

Fig. 1 Conception diagram of system

The advantages of this method are as follows. (1) Advections are created by putting a injection well and a pumping well together, enabling retention in the planned domain. In addition, for superficial control of the CO2 retention, examination is enabled by placing plural pumping wells. (2) The behavior of the CO2 after injection is determined by analyzing groundwater sampled from the pumping well. From the dissolution form and the solubility of the CO2 at a point in time, the retention state, and revision and prediction of the maximum stockpile are enabled. (3) A wide area of groundwater flow in the domain is required. (4) When groundwater flow exists, control of the CO2 retention position is enabled by controlling the pumping quantity of each pumping well. In addition, about the regional groundwater flow, as a coefficient of permeability, 1x10-7m/s in survey results of in Tono area and 0.3m/month (1.16*10-7m/s) in result of the measurement at the original position with the Osaka Zone water tray is observed. In this model area, the coefficient of permeability is thought at the same level. The groundwater moves around 30m in the period of around 15 years, it was thought that the influence of the regional groundwater flow was small.

2.2. Evaluation of storage possibility per unit

Most small- and medium-sized sources discharge 10,000-100,000 tons of CO2 per year. In this report, the assumed CO2 retention was 10,000 tons per year, and the model analysis was based on this value. Fig. 2 shows the flow of the analysis evaluation. We focused on the Okinawa area(Model A).

Site Selection

Estimation of Storage Possibility 1 "

Setting of site condition

Investigation of Structure and Properties of Storage Layer (Including Caprock)

Setting of Injection Rate

Setting of CO2 Meltability ^Component of Solvent Groundwater *Storage Depth

*Temperature of Storage Depth

Design of Storage Unit (Well Hydraulics) *Number/Aperture Diameter of Injection well

*Number/Aperture Diameter of Puming well ^Clearance of Ingection and Pumping Well ^Expansion Approach

Verification of Design Condition • Minute Analysis

FEM/FDM/LBM etc...

Fig. 2 Flow of analysis evaluation

The quality of water was found for a mean value of 2010 data of the Nishihara water purification plant entrance adjacent in the model area. Table 2 shows the quality of water in the model area.

Table-2 Quality of water in model area

Items mean value

Temperature^) 23.9

pH 7.0

Calcium / Magnesium (hardness) 28

Alkalinity 21

Conductivity *4(S/m) 151

Chloride ion (mg/l) 26.3

Chloride ion (mg/l) 13.6

Manganese and the compound chloride (mg/l) 0.014

Boron (mg/l) 0.016

Aluminum (mg/l) 0.0013

Ferrum (mg/l) 0.08

There was only one point of underground temperature data in Okinawa, and data are plotted as show in -Fig. 3. For the ground temperature incline, 1.45/100m, the earth surface temperature was 27.8 degrees Celsius. The representative characteristics of this value are future problems. Fig. 4 shows the results that demanded CO2 solubility using phreeqc from temperature incline data and ingredient data. The results for the Gulf of Osaka area(Model B) were put in the figure for reference.

Temperature (Celsius)

0 20 40 60 80

Fig. 3 Estimation of ground temperature incline

C02 cancentratiQn(g>kgw) 0 10 20 30 40 50 eo

■£ 300 o.

♦ "l L,

■ -♦- Area of Model A

- ♦ Area of Model B

Fig-4 Prediction of CO2 solubility in model area Based on these values, retention characteristics per unit were evaluated. The formulas are as follows.

Q= ln(R / r0) 1 <r

2jRCkD

' 1 R'

qi ln—

Qs = RcxAx<I>xH (3)

Q expresses the quantity of injection (m3/s) from the injection well, Rc expresses the decreasing rate of the water cycle effect by geologic inhomogeneity, k expresses the water permeance coefficient (m/s) of the injection layer, D expresses the stratum thickness (m) of the injection layer, s expresses the waterside difference (m), R expresses the influence radius (m), r0 expresses the well radius (m), qi expresses the pumping quantity (m3/s) from pumping well i, ri express the horizontal distance (m) from pumping well i to the at the waterside calculation spot, and n expresses the number (book) of the pumping well. A: Area (m2); H: Sum of layer thickness to store CO2 of (m); (p: Ave rage porosity of storage; [CO2]: concentration of CO2 (t/m3H2O).

With these formulas, the necessary injection hydraulic head difference is calculated, the hydraulic head fall of the injection position by the pumping well is calculated, and then the necessary injection pressure at the injection well was calculated. Fig. 5 shows a concept diagram of the water head difference.

Hydraulic Head Rising

Table 3 shows five cases of calculation conditions and results. Fig. 6 shows a hydraulic head distribution map for well diameter changed as Case-1. Fig. 7 shows a hydraulic head distribution map for separation distance of an infusion well and the pumping well for 200m and 300m. Fig. 8 shows a comparison where the lapse rate is low, because the geological structure is uncertain and investigations are insufficient.

Table-3 Cases of calculation conditions and results

Case Decreasing Ratio Well Diameter [mm] Clearance M Injection Water (tCOz/y) Pumping Necessary Well Injection Number Head (m] Influence Radius of Injection fml Influence Injection Radius of Water Pumping (m3/min fml 1 Pumping Water (m3/min]

1 1.0 116 200 1 4 95 286 66 0.42 0.42

2 1.0 143 200 1 4 99 278 66 0.42 0.42

3 1.0 143 200 2 4 200 609 119 0.84 0.85

4 1.0 143 300 2 4 200 576 119 0.84 0.85

5 0.6 | 146 200 1 4 160 498 66 0.42 0.42

From these results, the following things may be said about water cycle properties. Decreasing rate in the case of 1.0, the injection pressure (hydraulic head difference) necessary to ensure a water cycle for retention of more than 10,000 t-CO2/ year at 200 m estrangement distance is around 95-99 m. For a decreasing rate of 0.6, the necessary injection pressure increases to 1.6 times, and the necessary injection pressure (hydraulic head difference) increases to around 160 m.

It was assumed that this calculation result is 10,000 t-CO2 per year. However, from a comparison between Case 2 and Case 3, for double the water filling amount, necessary injection pressure becomes double. In consideration of the stability of the injection layer and the well, the necessary injection hydraulic head set the constant value of around 100m, it is necessary to increase units. The groundwater for water cycles can be ensured by pumping, but, it cannot be ensured with a decrease in decreasing rate in four pumping wells. By increasing the well diameter to 200 mm as these measures, the pumping quantity is increased, and sufficient circulation water is ensured.

Dis:ancGi from Injection Wsll (m) Fig. 6 Hydraulic head distribution map in Case-1

Distance from Injection Well (m) Fig. 7 Hydraulic head distribution map for clearance of 200m and 300m.

Distance from Injection Wall (m) Fig. 8 Comparison for low lapse rate

3. Conclusions

An existing aquifer is considered as the retention layer for CO2 storage. The injection method was considered as combined system of injection well and plural pumping wells placed planarly around a injection well. Using this method and at the assumed model area, the feasibility retaining CO2 underground were estimated by numerical analysis of a model area, and the behavior of CO2 injected in the stratum was analyzed.

Acknowledgements

This study received a subsidy of Keirin by JKA Foundation has been enforced by General ENAA Foundation. We write it down here and show gratitude.

References

[1] 1]Suzuki, K., Miida, H., Wada, H., Horikawa, S., Ebi, T., and Inaba, K.: Feasibility Study on CO2 Micro-Bubble Storage (CMS), GHGT-11, 2012

[2]Shidahara, T., Okumura, T, Miida, H., Shimoyama, M., Matsushita, N., Yamamoto, T., and Ogawa, T.: Storage potential and economic feasibility for CO2 microbubble storage (CMS) in Japan, GHGT-11, 2012

[3] Koide K., Maeda K.,Current Status of the Regional Hydrogeological Study Project in the Tono Area (II), PNC technical review , No.12(2001),pp.107-122 (in Japanese)