Patent ID: 8247463
Filing Date: 2012-08-21
Classification: B01D,B01J,C01B,C01C,C07C,Y02C,Y02P

Abstract:
1. A parallel process of coproducing methanol and ammonia using natural gas, liquid petroleum gas, butane or naphtha as a raw material, comprising the steps of: introducing a first feedstream containing the raw material into a first reformer and performing steam-reforming of the first feedstream to form a first synthesis gas containing carbon monoxide, carbon dioxide and hydrogen; reacting the first synthesis gas at a methanol synthesis pressure to form a mixture containing synthesized methanol and unreacted first synthesis gas in a methanol synthesis step; condensing and gas-liquid separating the mixture containing synthesized methanol and unreacted first synthesis gas; recovering hydrogen in a gas portion of the condensed and gas-liquid separated mixture which is rich in hydrogen from the unreacted first synthesis gas; introducing a second feedstream containing the raw material into a primary reformer and performing steam-reforming of the second feedstream to form a second synthesis gas containing methane, carbon monoxide, carbon dioxide and hydrogen; reforming unreformed methane remaining in the second synthesis gas with oxygen contained in air in a secondary reformer by partially combusting the second synthesis gas to provide the heat of reaction for the further reforming of the methane and form a crude synthesis gas containing carbon monoxide; converting the carbon monoxide in the crude synthesis gas into carbon dioxide; removing and recovering carbon dioxide from the crude synthesis gas; subjecting the crude synthesis gas to a final purification by methanating traces of carbon monoxide and carbon dioxide remaining in the crude synthesis gas and separating a purge gas therefrom; and synthesizing ammonia from the finally purified crude synthesis gas at an ammonia synthesis pressure; and comprising the additional steps of: adding the gas portion of the condensed and gas-liquid separated mixture which is rich in hydrogen to the crude synthesis gas contained carbon monoxide; cooling the first synthesis gas; separating and removing condensed water from the cooled first synthesis gas; mixing the cooled first synthesis gas with the water separated and removed therefrom with carbon dioxide obtained by pre-compressing the carbon dioxide obtained in the carbon dioxide removing and recovering step to form a mixed synthesis gas; compressing the mixed synthesis gas to the methanol synthesis pressure; and supplying the compressed mixed synthesis gas for methanol synthesis in the methanol synthesis step.