초록 ▼

The utilization amount of steam generated by heat recovery tends to decrease in a production process of an organic acid when the concentration of an organic acid solution obtained in a step of collecting an organic acid with a solvent such as water becomes high. The purpose of the invention is to fi

The utilization amount of steam generated by heat recovery tends to decrease in a production process of an organic acid when the concentration of an organic acid solution obtained in a step of collecting an organic acid with a solvent such as water becomes high. The purpose of the invention is to find an advantageous method for effectively utilizing reaction heat and contribute to global environmental preservation and saving product costs. The present invention provides a production method of an organic acid comprising carrying out a gas-phase catalytic oxidation reaction of raw material gas at the temperature from 250° C. to 450° C., recovering at least a part of reaction heat and/or heat generated in combustion of a waste as high pressure steam at a pressure of 1 MPaG or higher, supplying at least a part of the high pressure steam to a back pressure steam turbine connected with a blower to drive the blower, and supplying at least a part of discharged gas from the back pressure steam turbine, low pressure steam A at a pressure lower than 1 MPaG, to an absorption type refrigerator to utilize the low pressure steam A as a heat source of the absorption type refrigerator.

대표청구항 ▼

What is claimed is: 1. A production method of an organic acid comprising the steps of; carrying out a gas-phase catalytic oxidation reaction of raw material gas with molecular oxygen at a temperature from 250° C. to 450° C.; collecting gas of an organic acid, a product of the gas-phase ca

What is claimed is: 1. A production method of an organic acid comprising the steps of; carrying out a gas-phase catalytic oxidation reaction of raw material gas with molecular oxygen at a temperature from 250° C. to 450° C.; collecting gas of an organic acid, a product of the gas-phase catalytic oxidation reaction with a liquid medium to produce an organic acid solution; cooling the organic acid solution by using cold water obtained in an absorption refrigerator to crystallize the organic acid; recovering at least a part of reaction heat generated in the gas-phase catalytic oxidation reaction and/or heat generated in combustion of a waste from the production of the organic acid as high pressure steam at a pressure of 1 MPaG or higher; supplying at least a part of the high pressure steam to a back pressure steam turbine connected with a blower which supplies the molecular oxygen to drive the blower; and supplying at least a part of discharged gas from the back pressure steam turbine, low pressure steam A at a pressure lower than 1 MPaG, to the absorption refrigerator to utilize the low pressure steam A as a heat source of the absorption refrigerator. 2. The production method of an organic acid according to claim 1, further comprising, supplying at least a part of the low pressure steam A to a condensing steam turbine of a power generator to obtain electric power. 3. The production method of an organic acid according to claim 1, wherein heat from a reactor for the gas-phase catalytic oxidation reaction is recovered by a heat medium, and the high pressure steam at a pressure of 1 MPaG or higher is produced by using the heat medium after recovering the heat from the reactor. 4. The production method of an organic acid according to claim 1, wherein, the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium to produce an organic acid solution containing 80 mass % or more of the organic acid. 5. The production method of an organic acid according to claim 1, wherein the organic acid is (meth)acrylic acid. 6. A production method of an organic acid comprising the steps of; carrying out a gas-phase catalytic oxidation reaction of raw material gas with molecular oxygen at a temperature from 250° C. to 450° C.; collecting gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, with a liquid medium to produce an organic acid solution; cooling the organic acid solution by using cold water obtained in an absorption refrigerator to crystallize the organic acid; recovering at least a part of reaction heat generated in the gas-phase catalytic oxidation reaction and/or heat generated in combustion of a waste from the production of the organic acid as low pressure steam B at a pressure lower than 1 MpaG; and supplying at least a part of the low pressure steam B to the absorption refrigerator to utilize the low pressure steam B as a heat source of the absorption refrigerator. 7. The production method of an organic acid according to claim 6, further comprising, supplying at least a part of the low pressure steam B to a condensing steam turbine of a power generator to obtain electric power. 8. The production method of an organic acid according to claim 6, wherein, the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium to produce an organic acid solution containing 80 mass % or more of the organic acid. 9. The production method of an organic acid according to claim 6, wherein the organic acid is (meth)acrylic acid. 10. A production method of an organic acid comprising the steps of; carrying out a gas-phase catalytic oxidation reaction of raw material gas with molecular oxygen at a temperature from 250° C. to 450° C.; collecting gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, with a liquid medium to produce an organic acid solution; cooling the organic acid solution by using cold water obtained in an absorption refrigerator to crystallize the organic acid; recovering at least a part of reaction heat generated in the gas-phase catalytic oxidation reaction and/or heat generated in combustion of a waste from the production of the organic acid as high pressure steam at a pressure of 1 MPaG or higher; supplying at least a part of the high pressure steam to a back pressure steam turbine connected with a blower which supplies the molecular oxygen to drive the blower; recovering at least a part of the reaction heat and/or the heat generated in combustion of the waste as low pressure steam B at a pressure lower than 1 MpaG; and supplying at least a part of the low pressure steam B and at least a part of discharged gas from the back pressure steam turbine, low pressure steam A at a pressure lower than 1 MPaG, to the absorption refrigerator to utilize the low pressure steam A and B as a heat source of the absorption refrigerator. 11. The production method of an organic acid according to claim 10, further comprising, supplying at least a part of the low pressure steam A and/or the low pressure steam B to a condensing steam turbine of a power generator to obtain electric power. 12. The production method of an organic acid according to claim 10, wherein heat from a reactor for the gas-phase catalytic oxidation reaction is recovered by a heat medium, and the high pressure steam at a pressure of 1 MPaG or higher is produced by using the heat medium after recovering the heat from the reactor. 13. The production method of an organic acid according to claim 10, wherein, the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium to produce an organic acid solution containing 80 mass % or more of the organic acid. 14. The production method of an organic acid according to claim 10, wherein the organic acid is (meth)acrylic acid. 15. The production method of an organic acid according to claim 4, wherein the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium at an absorbing column, and gas discharged from the absorbing column is recycled to the step of carrying out the gas-phase catalytic oxidation reaction. 16. The production method of an organic acid according to claim 15, wherein the gas discharged from the absorbing column is cooled by a condenser and then recycled to the step of carrying out the gas-phase catalytic oxidation reaction. 17. The production method of an organic acid according to claim 8, wherein the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium at an absorbing column, and gas discharged from the absorbing column is recycled to the step of carrying out the gas-phase catalytic oxidation reaction. 18. The production method of an organic acid according to claim 17, wherein the gas discharged from the absorbing column is cooled by a condenser and then recycled to the step of carrying out the gas-phase catalytic oxidation reaction. 19. The production method of an organic acid according to claim 13, wherein the gas of an organic acid, a product of the gas-phase catalytic oxidation reaction, is collected with a liquid medium at an absorbing column, and gas discharged from the absorbing column is recycled to the step of carrying out the gas-phase catalytic oxidation reaction. 20. The production method of an organic acid according to claim 19, wherein the gas discharged from the absorbing column is cooled by a condenser and then recycled to the step of carrying out the gas-phase catalytic oxidation reaction.