COOPERATIVE EMISSION REDUCTION METHOD FOR SINTERING USING ENERGY-CARRYING COMPOSITE GAS MEDIUM

Abstract

A cooperative emission reduction method for sintering using an energy-carrying composite gas is disclosed. A surface of a sintered material is divided into an ignition section, a heat preservation section, a middle section, a flue gas heating section, and a machine tail section from a machine head to a machine tail of a sintering machine; according to flue gas components, temperature characteristics, and heat requirements of different sections, a hot exhaust gas is introduced to the ignition section for ignition, a hot exhaust gas is introduced to the heat preservation section and a hydrogen-rich gas is cascadingly sprayed synchronously, cascaded spraying of water vapor is coupled based on spraying of a hydrogen-rich gas in the middle section, and the high-temperature flue gas in the machine tail section and the flue gas in the ignition section and/or the heat preservation section are circulated to the heating section.

Claims

1. A cooperative emission reduction method fora sintering using an energy-carrying composite gas medium, comprising: introducing energy-carrying composite gas mediums with different compositions and heats to a surface of a sintered material of different sections in a sintering machine according to different flue gas components, temperature characteristics, and heat requirements of the different sections in the sintering machine to replace conventional air for the sintering, to achieve energy consumption reduction and emission reduction.

2. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 1, wherein the surface of the sintered material in the sintering machine is divided into an ignition section, a heat preservation section, a middle section, a flue gas heating section, and a machine tail section from a machine head to a machine tail.

3. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 2, wherein the ignition section occupies a region of 1-2 air boxes of the machine head of the sintering machine; the heat preservation section occupies a region of ⅙-¼ of a total length of the sintering machine; the middle section is a region from an end of heat preservation to a start of a flue gas heating up; the flue gas heating section is a region from the start of the flue gas heating up to the flue gas reaching a highest temperature; and the machine tail section is a region of 2-3 air boxes at the machine tail of the sintering machine.

4. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 1, wherein A first hot exhaust gas is introduced to the surface of the sintered material in the ignition section for an ignition; a composite gas of a second hot exhaust gas and a first hydrogen-rich gas is introduced to the surface of the sintered material in the heat preservation section; a composite gas of a second hydrogen-rich gas and water vapor is introduced to the surface of the sintered material in the middle section; and a high-temperature flue gas of the machine tail section and a flue gas of the ignition section and/or the heat preservation section are introduced to the surface of the sintered material in the flue gas heating section.

5. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 4, wherein the first hot exhaust gas with a temperature of 250-350° C. and an oxygen content of no less than 20% is introduced to the surface of the sintered material in the ignition section; the second hot exhaust gas with a temperature of 200-300° C. and an oxygen content of no less than 20% is introduced to the surface of the sintered material in the heat preservation section, and the first hydrogen-rich gas is sprayed in a manner of cascade spraying at the same time; the second hydrogen-rich gas is sprayed on the surface of the sintered material in the middle section, and the water vapor with a temperature of no less than 120° C. and a pressure of no less than 0.2 MPa is sprayed in the manner of cascade spraying at the same time; and a mixed gas of the high-temperature flue gas of the machine tail section and the flue gas of the ignition section and/or the heat preservation section with a temperature of no less than 120° C., an oxygen content of no less than 17%, and a CO.sub.2 content and a water vapor content of no greater than 4% is introduced to the surface of the sintered material in the flue gas heating section.

6. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 5, wherein the first hydrogen-rich gas is sprayed on the surface of the sintered material in the heat preservation section in the manner of cascade spraying, and a concentration in volume percent of the first hydrogen-rich gas uniformly decreases from 0.50-0.6% to 0.2-0.30% in a running direction of the sintering machine.

7. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 6, wherein the first hydrogen-rich gas is a hydrocarbon gas with a molecular weight of no less than 16.

8. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 5, wherein the water vapor is sprayed on the surface of the sintered material in the middle section in the manner of cascade spraying, and a concentration in volume percent of the water vapor uniformly increases from 0.3-0.4% to 0.7-0.9% in a running direction of the sintering machine; and the second hydrogen-rich gas with a concentration in volume percent of 0.2-0.5% is sprayed on the surface the a sintered material in the middle section.

9. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 8, wherein the second hydrogen-rich gas is a gas containing a hydrocarbon gas and/or a hydrogen gas.

10. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 5, wherein the first hot exhaust gas and the second hot exhaust gas are middle- or low-temperature exhaust gases produced by cooling sintered ore, or middle- or low-temperature exhaust gases produced by combusting a blast furnace gas or a converter gas.

11. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 2, wherein A first hot exhaust gas is introduced to the surface of the sintered material in the ignition section for an ignition; a composite gas of a second hot exhaust gas and a first hydrogen-rich gas is introduced to the surface of the sintered material in the heat preservation section; a composite gas of a second hydrogen-rich gas and water vapor is introduced to the surface of the sintered material in the middle section; and a high-temperature flue gas of the machine tail section and a flue gas of the ignition section and/or the heat preservation section are introduced to the surface of the sintered material in the flue gas heating section.

12. The cooperative emission reduction method for the sintering using the energy-carrying composite gas medium according to claim 3, wherein A first hot exhaust gas is introduced to the surface of the sintered material in the ignition section for an ignition; a composite gas of a second hot exhaust gas and a first hydrogen-rich gas is introduced to the surface of the sintered material in the heat preservation section; a composite gas of a second hydrogen-rich gas and water vapor is introduced to the surface of the sintered material in the middle section; and a high-temperature flue gas of the machine tail section and the flue gas of the ignition section and/or the heat preservation section are introduced to the surface of the sintered material in the flue gas heating section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a schematic diagram of a cooperative emission reduction method for sintering using an energy-carrying composite gas according to the present invention.

[0032] In FIG. 1: 1 represents an ignition cover; 2 represents a heat preservation cover; 3 represents a circulation gas cover; 4 represents a feeding trough; 5 represents a grate bar; 6 represents a chimney; 7 represents a dust collector I; 8 represents an air box; and 9 represents a dust collector II.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The optimal embodiment for implementing the present invention

[0034] The optimal implementation of the present invention

IMPLEMENTATIONS OF THE PRESENT INVENTION

[0035] The following examples are to further illustrate the present invention, but not to limit the scope of the present invention.

Example 1

[0036] A material was prepared according to a mass ratio of 59.81% of blended iron ore, 4.42% of dolomite, 5.38% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 3.85% of coke powder (the chemical composition of the sintered ore was 56.26% of TFe, 1.80% of R, 1.80% of MgO, and 10.83% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, a hot exhaust gas (with a temperature of 250° C. and an O.sub.2 content of 20.90%) of a ring cooler was introduced to an ignition cover of an ignition section (accounting for 2/24 of the length of the sintering machine) for hot air ignition. A hot exhaust gas (with a temperature of 200° C. and an O.sub.2 content of 20.90%) was introduced to a heat preservation cover of a heat preservation section (accounting for ⅙ of the length of the sintering machine) for heat preservation, a natural gas was sprayed into the heat preservation cover cascadingly, and the concentration uniformly decreases from 0.60% to 0.3% in the length direction of the sintering machine. 0.3% of a natural gas was sprayed to a middle section (accounting for 5/12 of the length of the sintering machine), water vapor (with a temperature of 120° C. and a pressure of 0.2 MPa) was sprayed cascadingly, and the concentration uniformly increases from 0.40% to 0.90% in the length direction of the sintering machine. A flue gas was introduced from air boxes No. 23 and No. 24 in a machine tail section of the sintering machine and air boxes in the ignition section and the heat preservation section. After being dedusted by a dust collector II, the flue gas was circulated to a circulation gas cover of the heating section (air boxes No. 17 to No. 22). The flue gas that enters a material surface has a temperature of 150° C., an O.sub.2 content of 17.80%, a CO.sub.2 content of 3.5%, and a water vapor content of 4.0%. Compared with conventional air sintering, by using a cooperative emission reduction technology for sintering using an energy-carrying composite gas, 10.71% of coke powder, 15% of CO.sub.2, 40% of CO, 30% of NO.sub.x, 7% of SO.sub.x, and 50% of dioxin can be reduced.

Example 2

[0037] A material was prepared according to a mass ratio of 59.81% of blended iron ore, 4.42% of dolomite, 5.38% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 3.85% of coke powder (the chemical composition of the sintered ore was 56.26% of TFe, 1.80% of R, 1.80% of MgO, and 10.83% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, a hot exhaust gas (with a temperature of 350° C. and an O.sub.2 content of 20.0%) of a ring cooler and a blast furnace gas was introduced to an ignition cover of an ignition section (accounting for 1/24 of the length of the sintering machine) for hot air ignition. A hot exhaust gas (with a temperature of 300° C. and an O.sub.2 content of 20.0%) was introduced to a heat preservation cover of a heat preservation section (accounting for ¼ of the length of the sintering machine) for heat preservation, a natural gas was sprayed into the heat preservation cover cascadingly, and the concentration uniformly decreases from 0.50% to 0.20% in the length direction of the sintering machine. 0.2% of a natural gas was sprayed to a middle section (accounting for ⅓ of the length of the sintering machine), water vapor (with a temperature of 134° C. and a pressure of 0.3 MPa) was sprayed cascadingly, and the concentration uniformly increases from 0.30% to 0.70% in the length direction of the sintering machine. A flue gas was introduced from air boxes No. 22 to No. 24 in a machine tail section of the sintering machine and air boxes in the ignition section and the heat preservation section. After being dedusted by a dust collector II, the flue gas was circulated to a circulation gas cover of the heating section (air boxes No. 16 to No. 21). The flue gas that enters a material surface has a temperature of 160° C., an O.sub.2 content of 18.0%, a CO.sub.2 content of 3.3%, and a water vapor content of 3.6%. Compared with conventional air sintering, by using a cooperative emission reduction technology for sintering using an energy-carrying composite gas, 10.71% of coke powder, 16% of CO.sub.2, 43% of CO, 32% of NO.sub.x, 8% of SO.sub.x, and 55% of dioxin can be reduced.

Example 3

[0038] A material was prepared according to a mass ratio of 60.03% of blended iron ore, 4.44% of dolomite, 5.37% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 3.62% of coke powder (the chemical composition of the sintered ore was 56.29% of TFe, 1.80% of R, 1.80% of MgO, and 10.81% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, a hot exhaust gas (with a temperature of 300° C. and an O.sub.2 content of 20.40%) of a ring cooler and a blast furnace gas was introduced to an ignition cover of an ignition section (accounting for 2/24 of the length of the sintering machine) for hot air ignition. A hot exhaust gas (with a temperature of 250° C. and an O.sub.2 content of 20.40%) was introduced to a heat preservation cover of a heat preservation section (accounting for ¼ of the length of the sintering machine) for heat preservation, a natural gas was sprayed into the heat preservation cover cascadingly, and the concentration uniformly decreases from 0.60% to 0.30% in the length direction of the sintering machine. 0.50% of a mixed gas of a natural gas and a hydrogen gas (a volume ratio of 5:1) was sprayed to a middle section (accounting for ⅓ of the length of the sintering machine), water vapor (with a temperature of 144° C. and a pressure of 0.4 MPa) was sprayed cascadingly, and the concentration uniformly increases from 0.30% to 0.80% in the length direction of the sintering machine. A flue gas was introduced from air boxes No. 23 and No. 24 in a machine tail section of the sintering machine and air boxes in the ignition section. After being dedusted by a dust collector II, the flue gas was circulated to a circulation gas cover of the heating section (air boxes No. 17 to No. 22). The flue gas that enters a material surface has a temperature of 120° C., an O.sub.2 content of 17.0%, a CO.sub.2 content of 4%, and a water vapor content of 4%. Compared with conventional sintering, by using a cooperative emission reduction technology for sintering using an energy-carrying composite gas, 16.07% of coke powder, 20% of CO.sub.2, 45% of CO, 35% of NO.sub.x, 10% of SO.sub.x, and 60% of dioxin can be reduced.

Comparative Example 1

[0039] A material was prepared according to a mass ratio of 59.36% of blended iron ore, 4.39% of dolomite, 5.40% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 4.31% of coke powder (the chemical composition of the sintered ore was 56.19% of TFe, 1.80% of R, 1.80% of MgO, and 10.88% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, and conventional air sintering was performed after conventional air ignition (an ignition cover accounting for 2/24 of the length of the sintering machine). In this case, the proportion of coke powder was 4.31%.

Comparative Example 2

[0040] A material was prepared according to a mass ratio of 59.36% of blended iron ore, 4.39% of dolomite, 5.40% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 4.31% of coke powder (the chemical composition of the sintered ore was 56.19% of TFe, 1.80% of R, 1.80% of MgO, and 10.88% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, a hot exhaust gas (with a temperature of 350° C. and an O.sub.2 content of 20.90%) of a ring cooler was introduced to an ignition cover of an ignition section (accounting for 2/24 of the length of the sintering machine) for hot air ignition, and conventional air sintering was then performed. Compared with conventional sintering, by using hot air ignition, 0% of coke powder, 1.5% of CO.sub.2, 1.5% of CO, 1.5% of NO.sub.x, 0.5% of SO.sub.x, and 1.5% of dioxin can be reduced.

Comparative Example 3

[0041] A material was prepared according to a mass ratio of 59.48% of blended iron ore, 4.40% of dolomite, 5.39% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 4.19% of coke powder (the chemical composition of the sintered ore was 56.21% of TFe, 1.80% of R, 1.80% of MgO, and 10.87% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, conventional air ignition (an ignition cover accounting for 2/24 of the length of the sintering machine) was used, and 0.5% of water vapor was sprayed to the middle of the sintering machine (at ⅓-⅗ of the length of the sintering machine). Compared with conventional sintering, after the water vapor was injected, 2.68% of coke powder, 4% of CO.sub.2, 8% of CO, 4% of NO.sub.x, 2% of SO.sub.x, and 25% of dioxin can be reduced.

Comparative Example 4

[0042] A material was prepared according to a mass ratio of 59.59% of blended iron ore, 4.41% of dolomite, 5.39% of limestone, 3.46% of quicklime, 13.85% of sintering-returned ore, 9.23% of blast furnace-returned ore, and 4.08% of coke powder (the chemical composition of the sintered ore was 56.22% of TFe, 1.80% of R, 1.80% of MgO, and 10.86% of CaO). A total area of a sintering machine was 450 m.sup.2, with a total of 24 air boxes. After being uniformly mixed and granulated, the raw material was distributed on a sintering trolley, conventional air ignition (an ignition cover accounting for 2/24 of the length of the sintering machine) was used, and 0.40% of a natural gas was sprayed to the middle and front of the sintering machine (at ⅙-½ of the length of the sintering machine). Compared with conventional sintering, after the natural gas was injected, 5.36% of coke powder, 8% of CO.sub.2, 9% of CO, 13% of NO.sub.x, 4% of SO.sub.x, and 8% of dioxin can be reduced.