Methanol recovery device in sulfuric acid concentration process

Abstract

The utility model provides a methanol recovery device in a sulfuric acid concentration process, which is characterized in that a gas phase pipeline is connected with a separating tower, the top of the separating tower is connected with a top inlet of a condenser through a pipeline, a bottom outlet of the condenser is connected with a top inlet of a separator, a bottom outlet of the separator is connected with a filter I, and the filter I is connected with a collecting tank; and the collecting tank is connected to the chloromethane synthesis kettle. The heated gas phase separated from the sulfuric acid enters a separation tower, the flow of a circulating water outlet of a condenser I is adjusted, the temperature of a gas phase outlet of the condenser I is controlled, the reflux ratio is adjusted, condensate enters the top of the separation tower, and sulfuric acid mist in the gas phase is removed through washing; the alcohol-containing water flowing out of the tower kettle of the separation tower is collected in a circulating tank and is forcibly circulated and cooled by a pump and a cooler, and the insufficient part is supplemented by adding concentrated condensate water or fresh water. Organic tail gas is firstly subjected to separation and demisting, then is condensed by the condenser II and is demisted by the separator, and condensed crude methanol is collected in a collecting tank and is conveyed to the outside by a pump to be recycled.

Description

Technical Field

[0001] The utility model relates to a methanol recovery technology in a sulfuric acid concentration process, which is a method for recovering raw materials in a chloromethane synthesis process. Background Art

[0002] In the chloromethane synthesis process, qualified chloromethane products are obtained by using concentrated sulfuric acid to dry out toxic impurities in the chloromethane synthesis gas, thereby producing dilute sulfuric acid containing organic matter as a by-product. The concentrated sulfuric acid is recovered through sulfuric acid concentration. During the hydrolysis and evaporation concentration process of the dilute sulfuric acid, the organic matter overflows into the liquid phase due to heat. Certain measures can be taken to recover the methanol in the organic matter. Summary of the Invention

[0003] The purpose of this utility model is to separate organic matter absorbed in sulfuric acid and recover the methanol component while concentrating it. To address the above technical issues, the utility model provides a methanol recovery device for a sulfuric acid concentration process, wherein a gas phase pipeline is connected to a separation tower, the top of the separation tower is connected to the top inlet of a condenser via a pipeline, the bottom outlet of the condenser is connected to the top inlet of a separator, the bottom outlet of the separator is connected to a first filter, the first filter is connected to a collection tank, and the collection tank is connected to a methyl chloride synthesis reactor.

[0004] The condenser is at least two stages of condensation equipment connected in series.

[0005] The bottom of the first-stage condensing equipment in the condenser is connected to the separation tower; the bottom of the second-stage condensing equipment or other condensing equipment is connected to the filter via a pipeline.

[0006] The bottom of the separation tower is connected to the second filter, the bottom of the second filter is connected to the circulation tank, and the circulation tank is cooled by being connected to the cooler.

[0007] This utility model utilizes a separation tower, with alcohol-containing acidic wastewater recovered from the bottom of the tower for reuse, and organic components recovered from the top of the tower. Utilizing the difference in melting and boiling points, the organic components undergo secondary condensation to produce liquid crude methanol and gaseous dimethyl ether, among others. The crude methanol obtained in this utility model is returned to the chloromethane synthesis system for recycling, while the gaseous dimethyl ether and other components are sent to an off-site treatment facility. The gas phase separated from the sulfuric acid by heat enters the separation tower. The reflux ratio is adjusted by regulating the flow rate at the condenser's circulating water outlet and controlling the condenser's gas phase outlet temperature. The condensate enters the top of the separation tower, where it is scrubbed to remove sulfuric acid mist from the gas phase. The alcohol-containing water flowing from the bottom of the separation tower is collected in a circulation tank, forcedly circulated and cooled by a pump and cooler, and reused as a hydrolysis feedstock. Any shortfall is supplemented by adding concentrated condensed water or fresh water. The organic tail gas is first separated and demisted, then subjected to secondary condensation in the condenser and demisted in the separator. The condensed crude methanol is collected in a collection tank and pumped to an off-site treatment facility for recycling. The waste gas is then desulfurized and sent to an off-site treatment facility after sulfuric acid mist and water are removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a process flow chart of the utility model. DETAILED DESCRIPTION

[0009] A methanol recovery device in a sulfuric acid concentration process, wherein a gas phase pipeline is connected to a separation tower 1, the top of the separation tower 1 is connected to the top inlet of a condenser 2 via a pipeline, the bottom outlet of the condenser 2 is connected to the top inlet of a separator 3, the bottom outlet of the separator 3 is connected to a filter 4, the filter 4 is connected to a collection tank 5, and the collection tank 5 is connected to a chloromethane synthesis kettle.

[0010] The condenser 2 is a two-stage condensing device connected in series. The bottom of the first stage condensing device in the condenser 2 is connected to the separation tower 1; the bottom of the second stage condensing device is connected to the filter 4 through a pipeline.

[0011] The bottom of the separation tower 1 is connected to the filter 2 6 , the bottom of the filter 2 6 is connected to the circulation tank 7 , and the circulation tank 7 is cooled by being connected to the cooler 8 .

[0012] like Figure 1 As shown, dilute sulfuric acid is heated to 150°C, and the organic components in it enter the separation tower in gaseous form. In the tower, the feed gas phase and the liquid phase at the top of the tower undergo countercurrent heat and mass transfer, scrubbing and removing sulfuric acid mist. The condenser's circulating water level is adjusted, and the condenser's gas phase outlet temperature is maintained at 65°C. The reflux ratio is adjusted to ensure sufficient reflux liquid to completely remove the sulfuric acid mist. Wastewater with a low methanol content is recovered from the bottom of the separation tower, and diluted sulfuric acid is reused. Crude methanol gas and non-condensable dimethyl ether (DME) are recovered at the top of the tower. The DME exhaust gas absorption regulating valve is adjusted to maintain the pressure at the top of the separation tower at 0.02 MPa. The organic exhaust undergoes demisting, secondary condensation in the condenser, and demisting in the separator, completing the condensation and separation of the crude methanol. The crude methanol is collected in a collection tank and pumped offsite for recycling.

Claims

1. A methanol recovery device in a sulfuric acid concentration process, characterized in that: The gas phase pipeline is connected to the separation tower (1), the top of the separation tower (1) is connected to the top inlet of the condenser (2) through a pipeline, the bottom outlet of the condenser (2) is connected to the top inlet of the separator (3), the bottom outlet of the separator (3) is connected to the filter 1 (4), the filter 1 (4) is connected to the collection tank (5), and the collection tank (5) is connected to the chloromethane synthesis kettle.

2. The methanol recovery device in the sulfuric acid concentration process according to claim 1, characterized in that: The condenser (2) is composed of at least two stages of condensing equipment connected in series.

3. The methanol recovery device in the sulfuric acid concentration process according to claim 2, characterized in that: The bottom of the first-stage condensing device in the condenser (2) is connected to the separation tower (1); the bottom of the second-stage condensing device or other condensing devices is connected to the filter (4) via a pipeline.

4. The methanol recovery device in the sulfuric acid concentration process according to claim 1, characterized in that: The bottom of the separation tower (1) is connected to the second filter (6), the bottom of the second filter (6) is connected to the circulation tank (7), and the circulation tank (7) is cooled by being connected to the cooler (8).

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