阅读说明：本技术 一种多级干燥去除液态氯甲烷中水分的装置及方法 (Device and method for removing moisture in liquid chloromethane through multistage drying ) 是由 蔡永胜 孟令东 张学贵 于 2020-12-18 设计创作，主要内容包括：本发明涉及一种多级干燥去除液态氯甲烷中水分的装置及方法,其特征在于：(1)将待干燥的氯甲烷打入氯甲烷储槽；(2)氯甲烷以20～30m～3/h打入一级循环干燥床上部,控制一级循环干燥床的温度在30～35℃,控制氯甲烷在一级循环干燥床和氯甲烷储槽之间循环,循环干燥60～120min后氯甲烷返回氯甲烷储槽；(3)一级干燥结束的氯甲烷以20～30m～3/h打入二级循环干燥床上部,控制二级循环干燥床的温度在30～35℃,氯甲烷经循环干燥床内的无水氯化钙干燥后经泵作用返回二级循环干燥床上部,控制氯甲烷在二级循环干燥床内自循环,循环干燥60～120min后氯甲烷送至成品罐区。本发明优点：氯甲烷中的含水量由0.1%～0.2%,降至0.05%以下,纯度由原来的≤99.00%提高至99.50%以上。(The invention relates to a device and a method for removing moisture in liquid chloromethane by multistage drying, which are characterized in that: (1) putting methyl chloride to be dried into a methyl chloride storage tank; (2) the methyl chloride is 20-30 m 3 Driving the mixture into the upper part of a primary circulating drying bed, controlling the temperature of the primary circulating drying bed to be 30-35 ℃, controlling methyl chloride to circulate between the primary circulating drying bed and a methyl chloride storage tank, and returning the methyl chloride to the methyl chloride storage tank after cyclic drying is carried out for 60-120 min; (3) the methyl chloride after the primary drying is 20-30 m 3 And/h, pumping the methyl chloride into the upper part of a secondary circulating drying bed, controlling the temperature of the secondary circulating drying bed to be 30-35 ℃, drying the methyl chloride by using anhydrous calcium chloride in the circulating drying bed, returning the methyl chloride to the upper part of the secondary circulating drying bed under the action of a pump, controlling the self-circulation of the methyl chloride in the secondary circulating drying bed, and conveying the methyl chloride to a finished product tank area after circularly drying for 60-120 min. The invention has the advantages that: the water content in the chloromethane is reduced to below 0.05 percent from 0.1 to 0.2 percent, and the purity is improved to above 99.50 percent from the original less than or equal to 99.00 percent.)

1. The device for removing moisture in liquid chloromethane by multistage drying is characterized by comprising the following equipment:

an outlet at the bottom of the methyl chloride storage tank is respectively connected with inlets at the upper parts of the first-stage circulating drying bed and the second-stage circulating drying bed through pipelines, an outlet at the lower part of the first-stage circulating drying bed is connected to the methyl chloride storage tank through a pipeline, and an outlet at the lower part of the second-stage circulating drying bed is connected to an inlet at the upper part of the second-stage circulating drying bed through a pipeline and a pump.

2. The apparatus for multistage drying and removal of water from liquid methyl chloride according to claim 1, wherein: and feeding tanks are arranged at the tops of the primary circulating drying bed and the secondary circulating drying bed.

3. The apparatus for multistage drying and removal of water from liquid methyl chloride according to claim 1, wherein: the upper parts of the first-stage circulating drying bed and the second-stage circulating drying bed adopt round seal heads, and the lower parts of the first-stage circulating drying bed and the second-stage circulating drying bed adopt conical seal heads.

4. The apparatus for multistage drying and removal of water from liquid methyl chloride according to claim 1, wherein: and the primary circulation drying bed and the secondary circulation drying bed are both provided with electric tracing bands.

5. The device for multistage drying and removal of water from liquid methyl chloride according to any one of claims 1 to 4, characterized in that: the desiccant required by the primary circulating drying bed and the secondary circulating drying bed is anhydrous calcium chloride.

6. A method for removing moisture in liquid chloromethane by multistage drying is characterized by comprising the following steps:

(1) putting methyl chloride to be dried into a methyl chloride storage tank;

(2) then, methyl chloride is added at a speed of 20-30 m³The water vapor is pumped into the upper part of the primary circulating drying bed, the temperature of the primary circulating drying bed is controlled to be 30-35 ℃, the methyl chloride is dried by anhydrous calcium chloride in the circulating drying bed and then returns to a methyl chloride storage tank, the methyl chloride is controlled to circulate between the primary circulating drying bed and the methyl chloride storage tank, and the methyl chloride returns to the methyl chloride storage tank after being dried for 60-120 min;

(3) the methyl chloride in the methyl chloride storage tank is controlled to be 20-30 m³And h, pumping the mixture into the upper part of a secondary circulating drying bed, controlling the temperature of the secondary circulating drying bed to be 30-35 ℃, drying the methyl chloride in the circulating drying bed through anhydrous calcium chloride, returning the methyl chloride to the upper part of the secondary circulating drying bed through the action of a pump, controlling the self-circulation of the methyl chloride in the secondary circulating drying bed, and conveying the methyl chloride to a finished product tank area after the methyl chloride is circularly dried for 60-120 min.

7. The method for removing moisture in liquid methyl chloride by multistage drying according to claim 6, wherein the method comprises the following steps: the water content of the chloromethane to be dried in the step (1) is 0.1-0.2%, and the purity is less than or equal to 99.00%.

8. The method for removing moisture in liquid methyl chloride by multistage drying according to claim 6, wherein the method comprises the following steps: the water content of the chloromethane obtained after drying in the step (2) is 0.06% -0.08%, and the purity is more than or equal to 99.40%.

9. The method for multistage drying of liquid methyl chloride to remove water according to any one of claims 6 to 8, wherein: the water content of the chloromethane obtained after drying in the step (3) is less than or equal to 0.05 percent, and the purity is more than or equal to 99.50 percent.

Technical Field

The invention belongs to the technical field of malt meal production, and relates to a device and a method for removing water in liquid chloromethane through multistage drying.

Background

The production process of maltol is divided into a Grignard working section, a chlorination working section, a sublimation working section, a crystallization working section and a drying working section; wherein, in the hydrolysis reaction in the chlorination working section, chloromethane is generated as a byproduct, and the liquid chloromethane still contains water (0.1-0.2 percent and the purity is less than or equal to 99.00 percent) and part of water-soluble impurities (such as methanol, dimethyl ether and the like) after primary impurity removal and recovery. At present, the methyl chloride is dried mainly by adopting a concentrated sulfuric acid drying method, the drying effect is good, but the problem that waste acid is difficult to treat cannot be solved well, and the recycling of the methyl chloride is severely restricted.

Disclosure of Invention

The invention aims to provide a device and a method for removing water in liquid methyl chloride by multistage drying in order to remove a small amount of water (1-2%) and part of water-soluble impurities (methanol, dimethyl ether and the like) in the liquid methyl chloride.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the device for removing moisture in liquid chloromethane by multistage drying is characterized by comprising the following equipment:

an outlet at the bottom of the methyl chloride storage tank is respectively connected with inlets at the upper parts of the first-stage circulating drying bed and the second-stage circulating drying bed through pipelines, an outlet at the lower part of the first-stage circulating drying bed is connected to the methyl chloride storage tank through a pipeline, and an outlet at the lower part of the second-stage circulating drying bed is connected to an inlet at the upper part of the second-stage circulating drying bed through a pipeline and a pump.

Furthermore, the top of the first-stage circulating drying bed and the top of the second-stage circulating drying bed are both provided with feeding tanks for filling anhydrous calcium chloride drying agents.

Furthermore, the upper parts of the first-stage circulating drying bed and the second-stage circulating drying bed adopt round end sockets, and the lower parts of the first-stage circulating drying bed and the second-stage circulating drying bed adopt conical end sockets.

Further, electric tracing bands are arranged on the primary circulation drying bed and the secondary circulation drying bed.

Furthermore, the desiccant required by the primary circulating drying bed and the secondary circulating drying bed is anhydrous calcium chloride.

A method for removing moisture in liquid chloromethane by multistage drying is characterized by comprising the following steps:

(1) putting methyl chloride (with water content of 0.1-0.2% and purity less than or equal to 99.00%) to be dried into a methyl chloride storage tank in advance;

(2) then, methyl chloride is added at a speed of 20-30 m³The water content of the methyl chloride is measured into the upper part of a primary circulating drying bed, the temperature of the primary circulating drying bed is controlled to be 30-35 ℃ (the water content and calcium chloride in the methyl chloride can form calcium chloride solution), the methyl chloride returns to a methyl chloride storage tank after being dried by a drying agent (anhydrous calcium chloride) in the circulating drying bed, the methyl chloride is controlled to circulate between the primary circulating drying bed and the methyl chloride storage tank, and the methyl chloride returns to the methyl chloride storage tank after being circularly dried for 60-120 min (the water content is 0.06-0.08%, and the purity is more than or equal to 99.40%);

(2) the methyl chloride is added at a rate of 20-30 m³The water content is measured in the upper part of a secondary circulating drying bed, the temperature of the secondary circulating drying bed is controlled to be 30-35 ℃, methyl chloride is dried by a drying agent (anhydrous calcium chloride) in the circulating drying bed and then returns to the upper part of the secondary circulating drying bed under the action of a pump, the self circulation of the methyl chloride in the secondary circulating drying bed is controlled, the methyl chloride is conveyed to a finished product tank area (the water content is less than or equal to 0.05 percent, and the purity is more than or equal to 99.50 percent) after the methyl chloride is circularly dried for 60-120 min.

The invention adopts two-stage circulation drying, and during the first-stage drying, the methyl chloride circulates between the first-stage circulation drying bed and the methyl chloride storage tank, so that most of water (0.04-0.012%) in the methyl chloride can be quickly removed, and meanwhile, the drying agent can be utilized to the greatest extent, and the replacement time of the catalyst is prolonged; and during secondary drying, the methyl chloride subjected to primary drying is continuously and circularly dried in a secondary circulating drying bed, and a small amount of residual moisture in the methyl chloride is further removed, so that the water content in the dichloromethane is reduced to below 0.05%, and the drying agent in the secondary drying bed can be reused in the primary circulating drying bed, so that the drying agent is fully utilized.

The invention has the advantages that:

1. after the drying of the primary circulating drying bed, the water content in the chloromethane is reduced to 0.06% -0.08%, and after the drying of the secondary circulating drying bed, the water content in the chloromethane is reduced to below 0.05%, and the purity is improved to above 99.50%;

2. the anhydrous calcium chloride is used as a drying agent, so that the drying agent is more environment-friendly, and the problem that a large amount of waste acid cannot be treated due to the adoption of concentrated sulfuric acid for drying can be avoided.

Drawings

FIG. 1 is a schematic diagram of an apparatus for multistage drying to remove moisture from liquid methyl chloride.

Detailed Description

The invention is further illustrated with reference to fig. 1:

a device for removing moisture in liquid methyl chloride through multistage drying comprises the following equipment:

the upper parts of the first-stage circulating drying bed and the second-stage circulating drying bed adopted by the invention are both provided with round seal heads, and the lower parts of the first-stage circulating drying bed and the second-stage circulating drying bed are provided with conical seal heads; electric tracing bands are arranged on the primary circulating drying bed and the secondary circulating drying bed for temperature control, feeding tanks (used for filling catalysts) are arranged at the tops of the primary circulating drying bed and the secondary circulating drying bed, and the catalysts filled in the primary circulating drying bed and the secondary circulating drying bed are anhydrous calcium chloride particles;

an outlet at the bottom of the methyl chloride storage tank is connected to the upper part of the first-stage circulating drying bed through a pipeline and a No. 1 circulating pump, the other part of the outlet is connected to the upper part of a feeding tank at the top of the first-stage circulating drying bed, and an outlet at the lower part of the first-stage circulating drying bed is connected to an inlet of the methyl chloride storage tank through a pipeline;

and an outlet at the bottom of the methyl chloride storage tank is connected to the upper part of the second-stage circulating drying bed through a pipeline and a 2# circulating pump, the other part of the outlet is connected to the upper part of a feeding tank at the top of the second-stage circulating drying bed, and an outlet at the lower part of the second-stage circulating drying bed is connected to the 2# circulating pump through a pipeline so as to realize self circulation.

A method for removing water in liquid chloromethane by multistage drying comprises the following specific implementation steps:

example 1

(1) The chloromethane to be dried is 18.0m³(the water content is 0.1 percent, and the purity is 98.97 percent) into a chloromethane storage tank;

(2) subsequently, the circulation pump # 1 was turned on to supply 25.0m of methyl chloride³The volume of the water is measured into the upper part of the primary circulating drying bed, the temperature of the primary circulating drying bed is controlled to be 32.5 ℃, the chloromethane is dried by anhydrous calcium chloride in the circulating drying bed and then returns to a chloromethane storage tank, the chloromethane is controlled to circulate between the primary circulating drying bed and the chloromethane storage tank, and the chloromethane returns to a chloromethane tank (containing water) after being dried circularly for 80.0minAmount 0.07%, purity 99.45%);

(3) the 2# circulation pump was turned on and the methyl chloride was added at 25.0m³The amount of the methyl chloride per hour is added into the upper part of a secondary circulating drying bed, the temperature of the secondary circulating drying bed is controlled to be 32.5 ℃, the methyl chloride is dried by a drying agent (anhydrous calcium chloride) in the circulating drying bed and then returns to the upper part of the secondary circulating drying bed under the action of a 2# circulating pump, the self-circulation of the methyl chloride in the secondary circulating drying bed is controlled, and the methyl chloride is conveyed to a finished product tank area (the water content is 0.025 percent and the purity is 99.73 percent) after being circularly dried for 80.0 min.

Example 2

(1) The chloromethane to be dried is 18m³(the water content is 0.12 percent, and the purity is 98.95 percent) into a chloromethane storage tank;

(2) then the circulation pump # 1 is turned on and the chloromethane is circulated at 25m³The water content of the methyl chloride is added into the upper part of the primary circulating drying bed, the temperature of the primary circulating drying bed is controlled to be 33.2 ℃, the methyl chloride returns to a methyl chloride storage tank after being dried by anhydrous calcium chloride in the circulating drying bed, the methyl chloride is controlled to circulate between the primary circulating drying bed and the methyl chloride storage tank, and the methyl chloride returns to the methyl chloride tank after being circularly dried for 85min (the water content is 0.06 percent, and the purity is 99.46 percent);

(3) the 2# circulation pump was turned on and the methyl chloride was added at 25m³The amount of the methyl chloride per hour is added into the upper part of a secondary circulating drying bed, the temperature of the secondary circulating drying bed is controlled to be 32.5 ℃, the methyl chloride is dried by a drying agent (anhydrous calcium chloride) in the circulating drying bed and then returns to the upper part of the secondary circulating drying bed under the action of a 2# circulating pump, the self-circulation of the methyl chloride in the secondary circulating drying bed is controlled, and the methyl chloride is conveyed to a finished product tank area (the water content is 0.04 percent and the purity is 99.72 percent) after being circularly dried for 100 min.

Example 3

(1) The chloromethane to be dried is 18m³(the water content is 0.15 percent, and the purity is 98.93 percent) into a chloromethane storage tank;

(2) then the circulation pump # 1 was turned on and the methyl chloride was added at 30m³The volume of the chlorine dioxide/h is added into the upper part of the primary circulating drying bed, the temperature of the primary circulating drying bed is controlled at 30 ℃, the chloromethane is dried by anhydrous calcium chloride in the circulating drying bed and then returns to a chloromethane storage tank, and the chloromethane is controlled to be arranged in the primary circulating drying bed and the chloromethaneCirculating among the methane storage tanks, and returning the methyl chloride to the methyl chloride tank after circulating and drying for 60min (the water content is 0.08 percent, and the purity is 99.43 percent);

(3) the 2# circulation pump was turned on and the methyl chloride was added at 25m³The amount of the methyl chloride per hour is added into the upper part of a secondary circulating drying bed, the temperature of the secondary circulating drying bed is controlled to be 31.5 ℃, the methyl chloride is dried by a drying agent (anhydrous calcium chloride) in the circulating drying bed and then returns to the upper part of the secondary circulating drying bed under the action of a 2# circulating pump, the self-circulation of the methyl chloride in the secondary circulating drying bed is controlled, and the methyl chloride is conveyed to a finished product tank area (the water content is 0.04 percent and the purity is 99.69 percent) after being circularly dried for 60 minutes.

When the drying performance of the primary circulating drying bed cannot meet the drying requirement, a new drying agent is filled in time, when the drying performance of the secondary circulating drying bed cannot meet the drying requirement, the new drying agent is filled in the primary drying bed, the original secondary drying bed is adjusted to be the primary drying bed for use, the original primary drying bed is adjusted to be the secondary drying bed for use, new calcium chloride is refilled after the calcium chloride saturated in the original secondary drying bed is completely consumed, and the drying sequence is adjusted back again.