Composite coagulant for flue gas desulfurization waste liquid treatment and its preparation method and application

Abstract

The invention provides a composite coagulant for treating flue gas desulfurization wastewater as well as a preparation method and application of the composite coagulant. The composite coagulant is prepared from poly aluminum chloride and cationic polyacrylamide, wherein the mass of the cationic polyacrylamide is 3-6% of the mass of the poly aluminum chloride. According to the invention, the poly aluminum chloride forms a series of hydrolytic hydroxyl ions with positive charges in water and has relatively strong ability of adsorbing charge neutrality and compressing an electric double layer and is conductive to promotion of elimination of colloid stability in water; the cationic polyacrylamide has a ring and chain structure and also has a hydrophilic group to realize very strong ability of adsorption bridging; the advantages of net fishing and bridging can be fully developed by use of a relatively small dosage, based on the elimination of colloid stability, and the removal rate of suspended particulate matters in the flue gas desulfurization wastewater is increased through sufficient adsorption of the suspended particulate matters. The results of the embodiments indicate that the composite coagulant provided by the invention can realize up to 95-99% of removal rate of the suspended particulate matters in the flue gas desulfurization wastewater.

Description

technical field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a composite coagulant for flue gas desulfurization waste liquid treatment and a preparation method and application thereof. Background technique

[0002] Nowadays, sulfur dioxide and acid rain pollution have become major environmental problems. The petrochemical industry will produce a large amount of sulfur-containing flue gas during the deep processing of sulfur-containing crude oil. As an important industry that emits sulfur dioxide and causes acid rain pollution, if no measures are taken, it will not only cause serious harm to the atmospheric environment, but also restrict the development of the power system. Catalytic cracking sulfur-containing flue gas is mainly treated by wet method. Among them, in the wet desulfurization, the sodium-alkali method is more commonly used, resulting in a large amount of fine suspended solids (2-5 μm catalyst dust accounts...

Examples

preparation example Construction

[0024] In the present invention, the method for preparing polyaluminum chloride preferably includes: mixing aluminum slag containing aluminum oxide with hydrochloric acid solution, performing hydrolysis and polymerization reactions, and obtaining polyaluminum chloride.

[0025] In the present invention, the mass content of aluminum oxide in the aluminum slag is preferably 15-40%, more preferably 20-30%. The present invention uses aluminum slag containing aluminum oxide as a raw material, which not only can realize the recycling of aluminum slag resources, but also helps to reduce the preparation cost of coagulant, thereby reducing the treatment cost of the flue gas desulfurization wastewater; The direct discharge of aluminum slag causes environmental pollution. The present invention has no special requirements on the source of the aluminum slag, and the aluminum slag well known to those skilled in the art can be used; in the embodiment of the present invention, the aluminum sl...

Embodiment 1

[0051] The aluminum slag provided by an aluminum profile processing factory in Jiangsu is screened and ground, and the undersize is obtained after being screened through a 10-mesh screen. The Al in the undersize is 2 o 3 The content is 20wt%, and the ratio of material to liquid is 1mL: 1g, add 4mol / L hydrochloric acid, stir at 80°C at a speed of 180r / min for 1h; then mature the stirred liquid at 45°C for 30h . Add cationic polyacrylamide, an organic polymer additive, to the cured feed liquid at a temperature of 85°C and under stirring conditions, wherein the amount of cationic polyacrylamide added is 3% of the mass of polyaluminum chloride, and the amount of cationic polyacrylamide The molecular weight is 6 million, the ionicity is 30%, and the stirring is continued for 30 minutes to obtain a composite coagulant.

[0052] According to the various indicators listed in the national standard GB / T22627-2008 of industrial grade polyaluminum chloride, the feed liquid after aging t...

Embodiment 2

[0054] The aluminum slag provided by an aluminum profile processing factory in Jiangsu is screened and ground, and the undersize is obtained after being screened through a 10-mesh screen. The Al in the undersize is 2 o 3 The content is 20wt%, and the ratio of material to liquid is 2mL: 1g, add 5.5mol / L hydrochloric acid, stir at 85°C at a speed of 240r / min for 1.5h; then mature the stirred liquid at 55°C Processing 40h. Add cationic polyacrylamide, an organic polymer additive, to the cured feed solution at a temperature of 75°C and under stirring conditions, wherein the amount of cationic polyacrylamide added is 4% of the mass of polyaluminium chloride, and the amount of cationic polyacrylamide The molecular weight is 8 million, the ionicity is 40%, and the stirring is continued for 60 minutes to obtain a composite coagulant.

[0055] According to the various indicators listed in the national standard GB / T22627-2008 of industrial grade polyaluminum chloride, the feed liquid ...

technical field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a composite coagulant for flue gas desulfurization waste liquid treatment and a preparation method and application thereof. Background technique

[0002] Nowadays, sulfur dioxide and acid rain pollution have become major environmental problems. The petrochemical industry will produce a large amount of sulfur-containing flue gas during the deep processing of sulfur-containing crude oil. As an important industry that emits sulfur dioxide and causes acid rain pollution, if no measures are taken, it will not only cause serious harm to the atmospheric environment, but also restrict the development of the power system. Catalytic cracking sulfur-containing flue gas is mainly treated by wet method. Among them, in the wet desulfurization, the sodium-alkali method is more commonly used, resulting in a large amount of fine suspended solids (2-5 μm catalyst dust accounts...

Examples

preparation example Construction

[0024] In the present invention, the method for preparing polyaluminum chloride preferably includes: mixing aluminum slag containing aluminum oxide with hydrochloric acid solution, performing hydrolysis and polymerization reactions, and obtaining polyaluminum chloride.

[0025] In the present invention, the mass content of aluminum oxide in the aluminum slag is preferably 15-40%, more preferably 20-30%. The present invention uses aluminum slag containing aluminum oxide as a raw material, which not only can realize the recycling of aluminum slag resources, but also helps to reduce the preparation cost of coagulant, thereby reducing the treatment cost of the flue gas desulfurization wastewater; The direct discharge of aluminum slag causes environmental pollution. The present invention has no special requirements on the source of the aluminum slag, and the aluminum slag well known to those skilled in the art can be used; in the embodiment of the present invention, the aluminum sl...

Embodiment 1

[0051] The aluminum slag provided by an aluminum profile processing factory in Jiangsu is screened and ground, and the undersize is obtained after being screened through a 10-mesh screen. The Al in the undersize is 2 o 3 The content is 20wt%, and the ratio of material to liquid is 1mL: 1g, add 4mol / L hydrochloric acid, stir at 80°C at a speed of 180r / min for 1h; then mature the stirred liquid at 45°C for 30h . Add cationic polyacrylamide, an organic polymer additive, to the cured feed liquid at a temperature of 85°C and under stirring conditions, wherein the amount of cationic polyacrylamide added is 3% of the mass of polyaluminum chloride, and the amount of cationic polyacrylamide The molecular weight is 6 million, the ionicity is 30%, and the stirring is continued for 30 minutes to obtain a composite coagulant.

[0052] According to the various indicators listed in the national standard GB / T22627-2008 of industrial grade polyaluminum chloride, the feed liquid after aging t...

Embodiment 2

[0054] The aluminum slag provided by an aluminum profile processing factory in Jiangsu is screened and ground, and the undersize is obtained after being screened through a 10-mesh screen. The Al in the undersize is 2 o 3 The content is 20wt%, and the ratio of material to liquid is 2mL: 1g, add 5.5mol / L hydrochloric acid, stir at 85°C at a speed of 240r / min for 1.5h; then mature the stirred liquid at 55°C Processing 40h. Add cationic polyacrylamide, an organic polymer additive, to the cured feed solution at a temperature of 75°C and under stirring conditions, wherein the amount of cationic polyacrylamide added is 4% of the mass of polyaluminium chloride, and the amount of cationic polyacrylamide The molecular weight is 8 million, the ionicity is 40%, and the stirring is continued for 60 minutes to obtain a composite coagulant.

[0055] According to the various indicators listed in the national standard GB / T22627-2008 of industrial grade polyaluminum chloride, the feed liquid ...