Device for recovering methanol from methanol-containing hydrochloric acid

Abstract

The utility model provides a device for recovering methanol from methanol-containing hydrochloric acid, which realizes the full utilization of raw materials in the production process of chloromethane, avoids the generation of waste liquid, protects the environment and reduces the production and operation cost of chloromethane. The condenser is arranged at the top of the methanol recovery tower, and an outlet of the condenser is connected with a methanol output pipe; a cold phase inlet of the feed preheater is connected with a methanol-containing hydrochloric acid feed pipe, a cold phase outlet is connected with a feed port of the methanol recovery tower, a hot phase inlet is connected with an outlet of the methanol recovery tower, and a hot phase outlet is connected with an inlet of the diluted hydrochloric acid cooler; an outlet of the diluted hydrochloric acid cooler is connected with an inlet of the diluted hydrochloric acid buffer tank through a cooler hydrochloric acid discharge pipe; an outlet of the diluted hydrochloric acid buffer tank is connected with an inlet of a diluted hydrochloric acid delivery pump; an outlet of the diluted hydrochloric acid delivery pump is connected with a hydrochloric acid output pipe; an inlet of the reboiler is connected with an outlet of the methanol recovery tower, and an outlet of the reboiler is connected with an inlet of the methanol recovery tower.

Description

Technical Field

[0001] The utility model relates to a device for recovering methanol from hydrochloric acid containing methanol, which is used in the production of methyl chloride. Background Art

[0002] Methanol chlorination has been widely used in the production of methyl chloride. However, in the production process of methyl chloride, methanol-containing hydrochloric acid waste liquid is inevitably produced, and direct discharge of methanol-containing hydrochloric acid waste liquid will cause environmental pollution and lead to waste of raw materials. Utility Model Content

[0003] The purpose of the utility model is to overcome the above-mentioned shortcomings in the prior art and to provide a device for recovering methanol from methanol-containing hydrochloric acid with a reasonable structural design, thereby achieving full utilization of raw materials in the production process of methyl chloride, avoiding the generation of waste liquid, protecting the environment, and reducing the cost of methyl chloride production and operation.

[0004] The technical scheme adopted by the utility model to solve the above-mentioned problem is: a device for recovering methanol from hydrochloric acid containing methanol, characterized in that it comprises a methanol recovery tower, a condenser, a reboiler, a feed preheater, a dilute hydrochloric acid cooler, a dilute hydrochloric acid buffer tank and a dilute hydrochloric acid delivery pump; the condenser is arranged on the top of the methanol recovery tower, and the outlet of the condenser is connected with a methanol output pipe; the cold phase inlet of the feed preheater is connected with a hydrochloric acid feed pipe containing methanol, the cold phase outlet is connected with the feed inlet of the methanol recovery tower, the hot phase inlet is connected with the outlet of the methanol recovery tower, and the hot phase outlet is connected with the inlet of the dilute hydrochloric acid cooler; the outlet of the dilute hydrochloric acid cooler is connected with the inlet of the dilute hydrochloric acid buffer tank through the hydrochloric acid discharge pipe of the cooler; the outlet of the dilute hydrochloric acid buffer tank is connected with the inlet of the dilute hydrochloric acid delivery pump, and the outlet of the dilute hydrochloric acid delivery pump is connected with the hydrochloric acid output pipe; the inlet of the reboiler is connected with the outlet of the methanol recovery tower, and the outlet of the reboiler is connected with the inlet of the methanol recovery tower.

[0005] The condenser described in the utility model is connected with a condenser circulating water feeding pipe and a condenser circulating water discharging pipe, and a circulating water regulating valve is arranged on the condenser circulating water discharging pipe.

[0006] The utility model provides a pressure gauge on the methanol output pipe.

[0007] The utility model provides a thermometer and a liquid level gauge on the methanol recovery tower.

[0008] The utility model provides a methanol-containing hydrochloric acid regulating valve on a methanol-containing hydrochloric acid feed pipe.

[0009] A circulating water inlet pipe and a circulating water return pipe are arranged on the dilute hydrochloric acid cooler of the utility model.

[0010] The utility model provides a dilute hydrochloric acid regulating valve on the hydrochloric acid discharge pipe of the cooler.

[0011] The utility model has a dilute hydrochloric acid regulating valve installed on a hydrochloric acid output pipe.

[0012] The utility model reboiler is connected with a steam feed pipe and a condensed water discharge pipe.

[0013] The utility model provides a steam regulating valve on the steam feed pipe and a drain valve on the condensate discharge pipe.

[0014] Compared with the prior art, the utility model has the following advantages and effects:

[0015] 1. The device uses the principle of different boiling points of methanol and dilute hydrochloric acid to distill and separate the methanol-containing hydrochloric acid waste liquid generated in the production of methyl chloride. Methanol with a concentration of 98% is obtained at the top of the tower, and dilute hydrochloric acid with a concentration of 17% is obtained at the bottom of the tower. The separated methanol and hydrochloric acid can be directly used as raw materials to participate in the production of methyl chloride again, which can improve the utilization rate of raw materials;

[0016] 2. The device recovers methanol through a condenser. The recovered methanol can be used as a raw material to react with hydrogen chloride to further generate methyl chloride, thereby improving the utilization rate of methanol;

[0017] 3. The device recovers dilute hydrochloric acid through the reboiler, feed preheater and dilute hydrochloric acid cooler arranged at the bottom of the methanol recovery tower, and the recovered dilute hydrochloric acid has a high concentration;

[0018] 4. The feed preheater in the device exchanges heat between the raw material and the tower bottom discharge, making full use of thermal energy, reducing energy consumption and achieving the purpose of energy saving;

[0019] 5. The device runs smoothly, is highly efficient and energy-saving, realizes the full utilization of raw materials in the production process of chloromethane, avoids the generation of waste liquid, reduces the cost of chloromethane production and operation, and protects the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and through examples. The following examples are provided to explain the present invention, but the present invention is not limited to the following examples.

[0022] The embodiment of the utility model comprises a methanol recovery tower 1, a condenser 2, a reboiler 3, a feed preheater 4, a dilute hydrochloric acid cooler 5, a dilute hydrochloric acid buffer tank 6 and a dilute hydrochloric acid delivery pump 7.

[0023] The condenser 2 is arranged at the top of the methanol recovery tower 1. The condenser circulating water feed pipe 23 and the condenser circulating water discharge pipe 22 are respectively connected to the side of the condenser 2, and a circulating water regulating valve 31 is arranged on the condenser circulating water discharge pipe 22. A thermometer 25 and a liquid level gauge 26 are arranged on the methanol recovery tower 1. The outlet of the condenser 2 is connected to the methanol output pipe 21, and a pressure gauge 30 is arranged on the methanol output pipe 21.

[0024] The cold phase inlet at the bottom of the feed preheater 4 is connected to a methanol-containing hydrochloric acid feed pipe 8, on which a methanol-containing hydrochloric acid regulating valve 28 is provided; the cold phase outlet at the top of the feed preheater 4 is connected to the feed port on the side of the methanol recovery tower 1 through a methanol recovery tower feed pipe 9. The hot phase inlet on the side of the feed preheater 4 is connected to the outlet of the methanol recovery tower 1 through a methanol recovery tower hydrochloric acid discharge pipe 14, and the hot phase outlet on the side of the feed preheater 4 is connected to the inlet of the dilute hydrochloric acid cooler 5 through a preheater hydrochloric acid discharge pipe 15.

[0025] The dilute hydrochloric acid cooler 5 is respectively provided with a circulating water inlet pipe 19 and a circulating water return pipe 20. The outlet of the dilute hydrochloric acid cooler 5 is connected to the inlet of the dilute hydrochloric acid buffer tank 6 through the cooler hydrochloric acid discharge pipe 16, and a dilute hydrochloric acid regulating valve 27 is installed on the cooler hydrochloric acid discharge pipe 16. The outlet of the dilute hydrochloric acid buffer tank 6 is connected to the inlet of the dilute hydrochloric acid delivery pump 7 through the buffer tank hydrochloric acid discharge pipe 17, and the outlet of the dilute hydrochloric acid delivery pump 7 is connected to a hydrochloric acid output pipe 18, and a dilute hydrochloric acid regulating valve 29 is installed on the hydrochloric acid output pipe 18.

[0026] The inlet at the bottom of the reboiler 3 is connected to the outlet at the bottom of the methanol recovery tower 1 through a liquid phase reflux pipe 10, and the outlet at the top of the reboiler 3 is connected to the inlet of the methanol recovery tower 1 through a gas phase reflux pipe 11. A steam feed pipe 12 and a condensed water discharge pipe 13 are connected to the side of the reboiler 3, a steam regulating valve 24 is provided on the steam feed pipe 12, and a steam trap 32 is provided on the condensed water discharge pipe 13.

[0027] The feed preheater 1, condenser 2, reboiler 3, feed preheater 4 and dilute hydrochloric acid cooler 5 are all made of graphite material, which reduces the acid corrosion of hydrochloric acid to the equipment, increases the life of the equipment, and realizes the long-term operation of the device.

[0028] The operation process of the utility model is as follows:

[0029] When the equipment is in operation, the methanol-containing hydrochloric acid, after the flow rate is adjusted by the methanol-containing hydrochloric acid regulating valve 28, enters the feed preheater 4 through the methanol-containing hydrochloric acid feed pipe 8, and the temperature of the methanol-containing hydrochloric acid rises from room temperature to 90°C. The heated methanol-containing hydrochloric acid enters the methanol recovery tower 1 through the methanol recovery tower feed pipe 9, and the methanol-containing hydrochloric acid completes the distillation operation in the methanol recovery tower 1. The recovered methanol is initially condensed to a concentration of 98.5% through the condenser 2 and directly enters the chloroform reactor through the methanol output pipe 21 to participate in the chloroform generation reaction. The tower bottom liquid is reboiled and vaporized through the reboiler 3 and then re-enters the methanol recovery tower 1. When the hydrochloric acid concentration in the tower bottom reaches 17%, the hydrochloric acid enters the feed preheater 4 through the methanol recovery tower hydrochloric acid discharge pipe 14 and is initially cooled to 70°C. The hydrochloric acid after initial cooling enters the dilute hydrochloric acid cooler 5 through the preheater hydrochloric acid discharge pipe 15 and is further cooled to 45°C. After cooling, the hydrochloric acid enters the dilute hydrochloric acid buffer tank 6 for buffering through the hydrochloric acid discharge pipe 16 of the cooler, and then enters the dilute hydrochloric acid delivery pump 7 through the hydrochloric acid discharge pipe 17 of the buffer tank to complete pressurization. The pressurized hydrochloric acid enters the tank area for storage through the hydrochloric acid output pipe 18. The condenser 2 and the dilute hydrochloric acid cooler 5 absorb the heat of methanol and hydrochloric acid respectively through circulating water, and the reboiler 3 completes the reboiling and vaporization of the tower bottom liquid through steam. According to the temperature of the methanol recovery tower 1, the opening degree of the steam regulating valve 24 is adjusted so that the temperature of the methanol recovery tower 1 is above the boiling point of methanol, and is monitored by the thermometer 25 on the methanol recovery tower 1. According to the pressure of the methanol output pipe 21, the opening degree of the circulating water regulating valve 31 is adjusted so that the pressure of methanol can be higher than 0.2 MPaG, and is monitored by the pressure gauge 30 on the methanol output pipe 21. According to the liquid level of the methanol recovery tower 1, the opening degree of the liquid level regulating valve 27 is adjusted so that the liquid level of the methanol recovery tower 1 is at a normal level, and is monitored by the liquid level gauge 26 on the methanol recovery tower 1. The output hydrochloric acid flow rate is controlled by adjusting the opening degree of the dilute hydrochloric acid regulating valve 29 on the hydrochloric acid output pipe 18.

[0030] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the utility model. Any equivalent changes or simple changes made based on the structure, features and principles described in the concept of the utility model patent are included in the protection scope of the utility model patent.

Claims

1. A device for recovering methanol from methanol-containing hydrochloric acid, characterized in that: The invention comprises a methanol recovery tower, a condenser, a reboiler, a feed preheater, a dilute hydrochloric acid cooler, a dilute hydrochloric acid buffer tank and a dilute hydrochloric acid delivery pump; the condenser is arranged at the top of the methanol recovery tower, and the outlet of the condenser is connected with a methanol output pipe; the cold phase inlet of the feed preheater is connected with a methanol-containing hydrochloric acid feed pipe, the cold phase outlet is connected with the feed inlet of the methanol recovery tower, the hot phase inlet is connected with the outlet of the methanol recovery tower, and the hot phase outlet is connected with the inlet of the dilute hydrochloric acid cooler; the outlet of the dilute hydrochloric acid cooler is connected with the inlet of the dilute hydrochloric acid buffer tank through the hydrochloric acid discharge pipe of the cooler; the outlet of the dilute hydrochloric acid buffer tank is connected with the inlet of the dilute hydrochloric acid delivery pump, and the outlet of the dilute hydrochloric acid delivery pump is connected with the hydrochloric acid output pipe; the inlet of the reboiler is connected with the outlet of the methanol recovery tower, and the outlet of the reboiler is connected with the inlet of the methanol recovery tower.

2. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: The condenser is connected with a condenser circulating water feed pipe and a condenser circulating water discharge pipe, and a circulating water regulating valve is arranged on the condenser circulating water discharge pipe.

3. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: A pressure gauge is provided on the methanol output pipe.

4. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: A thermometer and a liquid level gauge are provided on the methanol recovery tower.

5. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: A methanol-containing hydrochloric acid regulating valve is arranged on the methanol-containing hydrochloric acid feed pipe.

6. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: The dilute hydrochloric acid cooler is equipped with a circulating water inlet pipe and a circulating water return pipe.

7. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: A dilute hydrochloric acid regulating valve is installed on the hydrochloric acid discharge pipe of the cooler.

8. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: A dilute hydrochloric acid regulating valve is installed on the hydrochloric acid output pipe.

9. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 1, characterized in that: The reboiler is connected with a steam feed pipe and a condensed water discharge pipe.

10. The device for recovering methanol from methanol-containing hydrochloric acid according to claim 9, characterized in that: A steam regulating valve is provided on the steam feed pipe, and a steam trap is provided on the condensate discharge pipe.

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