Chemical looping gasification method for iron-rich sludge

Patent metadata

Field	Value
Publication number	US-12503659-B2
Application number	US-202519176118-A
Country	US
Kind code	B2
Filing date	Apr 10, 2025
Priority date	Apr 10, 2024
Publication date	Dec 23, 2025
Grant date	Dec 23, 2025

Abstract

A chemical looping gasification method for iron-rich sludge is provided, in which the iron-rich sludge is sequentially subjected to pressure filtration and crushing to obtain an iron-rich sludge particle with a moisture content of 40-50%. The iron-rich sludge particle and an iron-based oxygen carrier are subjected to a chemical looping gasification reaction in a fluidized bed reactor to form a sludge ash as a supplementary oxygen carrier. The chemical looping gasification is then performed with the supplementary oxygen carrier, the oxygen carrier and unreacted iron-rich sludge particle, while the iron-rich sludge gasification process, the produced syngas is rich in hydrogen and could be used as fuel.

First claim

What is claimed is:

1 . A chemical looping gasification method for iron-rich sludge, comprising:
subjecting a to-be-processed iron-rich sludge sample to pressure filtration and crushing to produce a first iron-rich sludge particle with a moisture content of 40-50% and a diameter of 0.5-1 mm; performing a chemical looping gasification of the first iron-rich sludge particle with an iron-based oxygen carrier and in a fluidized bed reactor to obtain a sludge ash as a supplemental oxygen carrier; performing the chemical looping gasification with the supplemental oxygen carrier, the iron-based oxygen carrier and unreacted first iron-rich sludge particle; and switching an intake atmosphere of the fluidized bed reactor to air, subjecting the sludge ash to crushing, floatation and discharging, and regenerating the iron-based oxygen carrier and the supplemental oxygen carrier to complete one cycle of chemical looping gasification.

2 . The method of claim 1 , wherein the iron-based oxygen carrier is selected from the group consisting of a copper-iron spinel oxygen carrier, a perovskite oxygen carrier, a sludge-ash oxygen carrier and a combination thereof.

3 . The method of claim 2 , wherein a chemical formula of the copper-iron spinel oxygen carrier is CuFe 2 O 4 , and a chemical formula of the perovskite oxygen carrier is CaMn 0.5 Fe 0.5 O 3-δ .

4 . The method of claim 2 , wherein the copper-iron spinel oxygen carrier is prepared through steps of:
subjecting red mud to crushing, drying and sieving to obtain a red mud powder; wherein a particle size of the red mud powder is less than 75 μm, and the drying is performed at 105° C. for 4 h; mixing the red mud powder, copper oxide and water to form a mixture; wherein the mixture has a moisture content of 10-15%, and a weight ratio of the red mud powder to the copper oxide is 17:3; and subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the copper-iron spinel oxygen carrier.

5 . The method of claim 4 , wherein the step of subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the copper-iron spinel oxygen carrier comprises:
pelletizing the mixture to form a pellet blank with a particle size of 0.5-1 mm; air-drying the pellet blank at 20-30° C. for 24-48 h to obtain an air-dried pellet blank; and oven-calcining the air-dried pellet blank through a predetermined drying program to obtain the copper-iron spinel oxygen carrier; wherein the predetermined drying program is performed through steps of: heating an oven at a heating rate of 5° C./min to 350° C. and holding the oven at 350° C. for 2 h; and heating the oven at a heating rate of 5° C./min to 900° C., and holding the oven at 900° C. for 6 h.

6 . The method of claim 2 , wherein the perovskite oxygen carrier is prepared through steps of:
subjecting red mud, manganese sand and calcium hydroxide together to crushing, drying and sieving to obtain a red mud powder, a manganese sand powder and a calcium oxide powder, wherein the red mud powder, the manganese sand powder and the calcium oxide powder each have a particle size of less than 75 μm, and the drying is performed at 105° C. for 4 h; mixing the red mud powder, the manganese sand powder, the calcium oxide powder and water to form a mixture; wherein the mixture has a moisture content of 10-15%, and a weight ratio of the red mud powder to the manganese sand powder to the calcium oxide powder is 36:38:26; and subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the perovskite-type oxygen carrier.

7 . The method of claim 6 , wherein the step of subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the perovskite-type oxygen carrier comprises:
pelletizing the mixture to form a pellet blank having a particle size of 0.5-1 mm; air-drying the pellet blank at 20-30° C. for 24-48 h to obtain an air-dried pellet blank; and oven-calcining the air-dried pellet blank through a predetermined drying program to obtain the perovskite-type oxygen carrier; wherein the predetermined drying program is performed through steps of: heating an oven at a heating rate of 5° C./min to 350° C., and holding the oven at 350° C. for 2 h; and heating the oven at a heating rate of 5° C./min to 850° C., and holding the oven at 850° C. for 6 h.

8 . The method of claim 2 , wherein the sludge-ash oxygen carrier is prepared through steps of:
crushing an iron-rich sludge material followed by drying at 105° C. for 4 h to obtain a second iron-rich sludge particle; subjecting the second iron-rich sludge particle to ashing and sieving to obtain a sludge ash powder with a particle size of less than 75 μm; mixing the sludge ash powder with water to form a mixture; and subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the sludge-ash oxygen carrier.

9 . The method of claim 8 , wherein the step of subjecting the mixture to pelletization, air-drying and oven-calcination to obtain the sludge-ash oxygen carrier comprises:
pelletizing the mixture to form a pellet blank having a particle size of 0.5-1 mm; air-drying the pellet blank at 20-30° C. for 24-48 h to obtain an air-dried pellet blank; and oven-calcining the air-dried pellet blank through a predetermined drying program to obtain the sludge-ash oxygen carrier; wherein the predetermined drying program is performed through steps of: heating an oven at a heating rate of 5° C./min to 350° C., and holding the oven at 350° C. for 2 h; and heating the oven at a heating rate of 5° C./min to 850° C., and holding the oven at 850° C. for 6 h.

Assignees

• Univ Shandong Science & Tech

Inventors

• Wang Cuiping
• Wang Kun
• Cui Weiwei
• Yao Sheng
• Li Jie
• Yuan Xiaoying
• Chang Guozhang

Classifications

• C10J2300/0946

  Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale · CPC title

• C02F11/122

  using filter presses (C02F11/123 takes precedence) · CPC title

• C10J3/463

  in stationary fluidised beds · CPC title

• B01J35/40

  characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77) · CPC title

• B01J37/0063

  Granulating · CPC title