Device and method for purifying methanol-to-olefin device washing water

Abstract

The invention relates to the field of coal chemical wastewater treatment, in particular to a device and a method for purifying methanol-to-olefin device washing water. The method comprises the following steps: pumping out the washing water from the bottom of a washing tower, and sending to a granular-bed separator; enabling the washing water to run through the granular bed in a horizontal direction, intercepting particulate matters in water, and agglomerating microfine oil droplets in the water under the oil substance adsorbing and agglomerating actions of medium particles in the granular bed;performing settling separation on the agglomerated oil droplets under the action of gravity; after the granular bed adsorbs the particulate matters in the water till a saturated state, feeding wastewater from the bottom of the granular bed, mixing with gas, fluidizing the medium particles till a boiling state, releasing solid pollutants between bed layers, and sending the pollutants to a solid concentrating unit along with backwashing liquid. By the method, separation of catalyst particles and the oil substances from the washing water is achieved.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and relates to a purification device and a purification method for washing water of a methanol-to-olefins device. Background technique [0002] Methanol to Olefins, referred to as MTO (Methanol to Olefins), refers to the process of preparing low-carbon olefins through catalytic reactions using methanol as a raw material. The reaction is generally realized by a fluidized bed reactor, and the currently used catalyst is SAPO-34 molecular sieve. Part of the catalyst particles will be entrained in the reaction product gas, and some unreacted methanol, aldehydes, ethers, alkanes, aromatics and other by-products will enter the water system together. After the product gas is cooled and washed by the quenching tower, most of the catalyst particles remain in the quenching water, while organic by-products and a small amount of fine catalyst powder enter the washing tower and remain in the washing w...

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Problems solved by technology

[0005] In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a purification device and purification method for the washing water of a methanol-to-olefins plant, which realizes the purification of spent catalyst fine powder and oil waxes in the water-washing water of a methanol-to-olefins plant. The removal of substances is simple and effective, and it solves the problem of clogging of equipment and pipes in the washing water circulation system caused by the high content of oil wax and catalyst in the washing water of the current MTO device, and reduces the cost of heat exchangers, air coolers and water washing tower trays. The frequency of cleaning effectively prolongs the continuous operation period of the system

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