Process for treating waste from a pithead power plant and for sequestrating carbon dioxide discharged therefrom

Patent metadata

Field	Value
Publication number	US-10052668-B1
Application number	US-201715689980-A
Country	US
Kind code	B1
Filing date	Aug 29, 2017
Priority date	Apr 26, 2017
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A process for treating waste from a pithead power plant and sequestrating carbon dioxide discharged therefrom is provided. A mixed material of solid waste from the power plant, cement and a mixing liquid is filled into a depleted coal mine and compacted. A hydrating liquid is then injected into the filler after compaction to cause hydration. After that, carbon dioxide discharged from the power plant is injected to mineralize the carbon dioxide, thereby achieving carbon dioxide sequestration and reinforcement of the depleted coal mine. The invention utilizes abundant basic oxides present in the solid waste, and the fact that calcium hydroxide and tobermorite present in the hydrated cement chemically react with the injected carbon dioxide to produce stable carbonates in solid, and thus simultaneously achieves carbon dioxide sequestration, treatment of solid waste, and reinforcement of a depleted coal mine.

First claim

What is claimed is:

1. A process for treating waste from a pithead power plant and sequestrating carbon dioxide discharged therefrom, comprising steps of:
(A) mixing solid waste from the pithead power plant with cement and a mixing liquid to produce a mixed material;
(B) filling the mixed material produced in step (A) into a depleted coal mine and performing a compaction operation;
(C) injecting a hydrating liquid into the filler after compaction to cause hydration; and
(D) injecting carbon dioxide discharged from the pithead power plant into the filler after hydration and then closing the mine to mineralize the carbon dioxide, thereby achieving carbon dioxide sequestration and reinforcement of the depleted coal mine.

2. The process of claim 1 , wherein the solid waste in said step (A) comprises one or more of slag, ash, coal gangue, and architectural waste.

3. The process of claim 2 , wherein, in step (A), a mass ratio of the solid waste to the cement is 3/1 to 2.

4. The process of claim 1 , wherein, in said step (A), a mass ratio of the solid waste to the cement is 3/1 to 2.

5. The process of claim 4 , wherein, in said step (A), a water-cement ratio of the mixed material is 0.2 to 0.25.

6. The process of claim 1 , wherein a compaction pressure as used in said step (B) is 30 to 50 MPa.

7. The process of claim 6 , wherein a porosity of the filler after compaction in said step (B) is 0.3 to 0.45.

8. The process of claim 1 , wherein a porosity of the filler after compaction in said step (B) is 0.3 to 0.45.

9. The process of claim 8 , wherein an injection amount of the hydrating liquid in said step (C) is 40% to 60% of a pore volume of the filler.

10. The process of claim 9 , wherein a hydrating time in said step (C) is 25 to 35 days.

11. The process of claim 1 , wherein a hydrating time in said step (C) is 25 to 35 days.

12. The process of claim 1 , wherein, in said step (D), the carbon dioxide is injected under a constant pressure.

13. The process of claim 12 , wherein, in said step (D), the carbon dioxide is reinjected every 3 to 5 years during the mine closure.

14. The process of claim 1 , wherein, in said step (D), the carbon dioxide is reinjected every 3 to 5 years during the mine closure.

Assignees

• Univ Tsinghua

Inventors

• Jiang Peixue
• Xu Ruina
• He Di

Classifications

• C04B2111/00019

  Carbon dioxide sequestration · CPC title

• C04B2111/00017

  Aspects relating to the protection of the environment · CPC title

• C04B40/0231

  Carbon dioxide hardening · CPC title

• B09B1/008 Primary

  Subterranean disposal, e.g. in boreholes or subsurface fractures · CPC title

• B09B3/0041

  Operations & Transport · mapped topic