Production device for preparing dichloropropanol through glycerol tower type chlorination

Abstract

The utility model relates to the technical field of dichloropropanol preparation through chlorination, in particular to a production device for preparing dichloropropanol through glycerol tower type chlorination. Comprising a first-stage reaction unit and a second-stage reaction unit, the first-stage reaction unit comprises a first-stage chlorination tower, a first-stage circulation kettle connected to the first-stage chlorination tower and a first-stage circulation heat exchanger connected between the first-stage chlorination tower and the first-stage circulation kettle, and a first-stage chlorination tower condenser is arranged at the top of the first-stage chlorination tower; the second-stage reaction unit comprises a second-stage chlorination tower, a second-stage circulation kettle connected to the second-stage chlorination tower, and a second-stage circulation heat exchanger connected between the second-stage chlorination tower and the second-stage circulation kettle; a second-stage chlorination tower condenser is arranged at the top of the second-stage chlorination tower; according to the utility model, a gas-phase material and a liquid-phase material can be mixed more uniformly, moisture can be efficiently and timely moved out of a reaction system, the positive reaction rate is high, the conversion rate of glycerol and hydrogen chloride is high, and the energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of preparing dichloropropane by chlorination, in particular to a production device for preparing dichloropropane by chlorination of glycerol tower. Background Art

[0002] The use of the glycerol method to produce epichlorohydrin has freed us from dependence on petroleum resources as raw materials, saved a large amount of petroleum resources, and reduced environmental pollution; it has made full use of crop biological resources, facilitated the recycling of resources and the sustainable development of the economy.

[0003] The glycerol process for producing epichlorohydrin uses glycerol and HCl as raw materials. A chlorination reaction occurs in the presence of a catalyst to produce dichloropropanol. The dichloropropanol then undergoes cyclization in the presence of an alkali to produce epichlorohydrin. Glycerol chlorination is a key focus of research in the glycerol process for producing epichlorohydrin.

[0004] The basic principle of producing dichloropropane by glycerol chlorination is that glycerol reacts with hydrogen chloride or hydrochloric acid to produce dichloropropane in the presence of a catalyst, carboxylic acid or its derivatives. The reaction equation is:

[0005]

[0006] The chlorination reaction is an exothermic, reversible reaction between glycerol and hydrogen chloride to produce water and dichloropropane. The chlorination of glycerol to dichloropropane is a reversible bimolecular nucleophilic substitution reaction, initially producing monochloropropanediol. The reaction proceeds at relatively low temperatures, but higher temperatures are required to convert monochloropropanediol to dichloropropane. Dichloropropane consists of two isomers: 1,3-dichloropropane and 2,3-dichloropropane.

[0007] The current industrial glycerol chlorination reaction has the following disadvantages: ① The chlorination reaction of glycerol with hydrogen chloride is a gas-liquid reaction, which requires sufficient contact between the gas and liquid; ② The residence time of the glycerol chlorination reaction is long, so a larger reactor volume is required; ③ The multi-reactor series process has high energy consumption and high equipment investment; ④ The utilization rate of HCl is low. Summary of the Invention

[0008] In view of the above situation, in order to overcome the defects of the prior art, the utility model provides a production device for preparing dichloropropane by glycerol tower chlorination, which has the advantages of easy and sufficient contact between HCl and glycerol, high HCl utilization rate, small number of equipment, small reactor volume and small floor space.

[0009] To achieve the above object, the utility model provides the following technical solution: a device for preparing dichloropropane by tower chlorination of glycerol, comprising two or more reaction units, each of which is provided with a chlorination tower;

[0010] The reaction unit includes a primary reaction unit and a secondary reaction unit.

[0011] The primary reaction unit includes a primary chlorination tower, a primary circulation kettle connected to the primary chlorination tower, a primary circulation heat exchanger connected between the primary chlorination tower and the primary circulation kettle, and a primary chlorination tower condenser is provided on the top of the primary chlorination tower;

[0012] The secondary reaction unit includes a secondary chlorination tower, a secondary circulation kettle connected to the secondary chlorination tower, a secondary circulation heat exchanger connected between the secondary chlorination tower and the secondary circulation kettle, and a secondary chlorination tower condenser is provided on the top of the secondary chlorination tower;

[0013] The primary circulation kettle is connected to the secondary circulation kettle, or is connected to the connecting pipe between the secondary circulation heat exchanger and the secondary circulation kettle;

[0014] Described secondary chlorination tower condenser is connected with the bottom of primary chlorination tower;

[0015] A raw material inlet is provided at the top of the first-level chlorination tower, a hydrogen chloride inlet is provided at the bottom of the second-level chlorination tower, and a distillate outlet is provided on the condenser of the second-level chlorination tower.

[0016] Furthermore, the bottoms of the primary chlorination tower and the secondary chlorination tower are both provided with liquid outlets, the liquid outlet of the primary chlorination tower is connected to the primary circulation kettle, and the liquid outlet of the secondary chlorination tower is connected to the secondary circulation kettle.

[0017] Furthermore, the primary circulation heat exchanger is connected to the middle of the primary chlorination tower, the secondary circulation heat exchanger is connected to the upper part of the secondary chlorination tower, and the primary chlorination tower condenser is provided with a tail gas outlet.

[0018] Furthermore, a primary circulation pump is provided between the primary circulation kettle and the primary circulation heat exchanger, and a secondary circulation pump is provided between the secondary circulation kettle and the secondary circulation heat exchanger.

[0019] Furthermore, the secondary circulation kettle is provided with a produced liquid discharge outlet.

[0020] Furthermore, the primary chlorination tower and the secondary chlorination tower include a shell, a gas inlet and a liquid outlet at the lower end of the shell, a gas outlet and a first liquid inlet at the upper end of the shell, and a second liquid inlet at the middle part of the shell.

[0021] Furthermore, the shell is provided with a packing section, a liquid distributor and a liquid collector in sequence from bottom to top. The second liquid inlet is located at the upper part of the liquid collector, and the packing section is 2 or more.

[0022] Furthermore, the reaction temperature of the first-stage chlorination tower and the second-stage chlorination tower is 100-140° C., the reaction pressure is -0.05-0.1 MPa, and the residence time is 6-12 hours.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The utility model can make the gas phase material and the liquid phase material mix more uniformly, the moisture can be removed from the reaction system efficiently and timely, the forward reaction rate is fast, the conversion rate of glycerol and hydrogen chloride is high, the energy consumption is reduced, the floor space is reduced, and the moisture of the product is removed during the reaction process, thereby improving the forward reaction rate and increasing the glycerol conversion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the connection structure of Example 1 of the utility model;

[0026] Figure 2 This is a schematic diagram of the internal structure of the chlorination tower of the utility model;

[0027] Figure 3 This is a schematic diagram of the connection structure of Example 3 of the present utility model;

[0028] Figure 4 This is a schematic diagram of the connection structure of Example 4 of the present utility model;

[0029] In the picture:

[0030] A first-stage chlorination tower 1, a first-stage liquid outlet 11, a raw material inlet 12, a shell 13, a gas inlet 14, a liquid outlet 15,

[0031] Gas outlet 16, first liquid inlet 17, second liquid inlet 18, packing section 19, liquid distributor 20, liquid collector 21, primary circulation kettle 2, primary circulation heat exchanger 3, primary chlorination tower condenser 4, tail gas outlet 41, primary circulation pump 5, secondary chlorination tower 6, secondary liquid outlet 61, hydrogen chloride inlet 62, secondary circulation kettle 7, produced liquid outlet 71, secondary circulation heat exchanger 8, secondary chlorination tower condenser 9, distillate outlet 91, secondary circulation pump 10. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Example 1:

[0034] Depend on Figure 1-2 As shown, a production device for preparing dichloropropane by glycerol tower chlorination includes a primary reaction unit and a secondary reaction unit.

[0035] The primary reaction unit includes a primary chlorination tower 1, a primary circulation kettle 2 connected to the primary chlorination tower 1, a primary circulation heat exchanger 3 connected between the primary chlorination tower 1 and the primary circulation kettle 2, a primary chlorination tower condenser 4 is provided on the top of the primary chlorination tower 1; a primary circulation pump 5 is further provided between the primary circulation kettle 2 and the primary circulation heat exchanger 3,

[0036] The first-level chlorination tower 1 is provided with a first-level liquid outlet 11 at the bottom, which is connected to a first-level circulation kettle 2. The first-level circulation heat exchanger 3 is connected to the middle of the first-level chlorination tower 1. The first-level chlorination tower condenser 4 is provided with an exhaust gas outlet 41. The first-level chlorination tower 1 is provided with a raw material inlet 12 at the top. The first-level chlorination tower 1 has a reaction temperature of 100 to 140°C, a reaction pressure of -0.05 to 0.1 MPa, a residence time of 6 to 12 hours, a raw material glycerin content of ≥80%, and a molar flow ratio of hydrogen chloride to glycerin of 2 to 3:1.

[0037] The secondary reaction unit includes a secondary chlorination tower 6, a secondary circulation kettle 7 connected to the secondary chlorination tower 6, a secondary circulation heat exchanger 8 connected between the secondary chlorination tower 6 and the secondary circulation kettle 7, a secondary chlorination tower condenser 9 is provided on the top of the secondary chlorination tower 6; and a secondary circulation pump 10 is also provided between the secondary circulation kettle 7 and the secondary circulation heat exchanger 8.

[0038] The secondary chlorination tower 6 has a secondary liquid outlet 61 at its bottom, which is connected to a secondary circulation kettle 7. A secondary circulation heat exchanger 8 is connected to the top of the secondary chlorination tower 6. A hydrogen chloride inlet 62 is provided at the bottom of the secondary chlorination tower 6. The secondary chlorination tower condenser 9 has a distillate outlet 91. A produced liquid outlet 71 is provided on the secondary circulation kettle 7. The reaction temperature in the secondary chlorination tower 6 is 100-130°C, the reaction pressure is atmospheric pressure to 0.1 MPa, the residence time is 6-12 hours, and the feedstock hydrogen chloride content is ≥90%.

[0039] The primary chlorination tower 1 and the secondary chlorination tower 6 are packed towers or plate towers, and the packings are Raschig rings, Pall rings, stepped rings, saddle rings, corrugated packings, etc.; the plate towers are sieve plate towers, bubble cap towers, etc. The primary circulation kettle 2 is connected to the secondary circulation kettle 7, and the secondary chlorination tower condenser 9 is connected to the bottom of the primary chlorination tower 1.

[0040] Primary reaction stage: Raw materials glycerin and catalyst (oxalic acid, adipic acid, chloroacetic acid, etc.) are sprayed into the raw material inlet 12 of the primary chlorination tower 1. After the reaction, they flow into the primary circulation kettle 2 from the liquid outlet. The primary circulation pump 5 heats the liquid material in the primary circulation kettle 2 through the primary circulation heat exchanger 3 and then adds it from the tower. After being evenly distributed by the distributor, it enters the packing section or enters the lower tower plate through the downcomer. The tower bottom is the hydrogen chloride tail gas from the secondary chlorination tower 6. The rising hydrogen chloride gas and the descending liquid form a countercurrent in the tower, so that the liquid material and hydrogen chloride are fully contacted. The chlorination reaction product is buffered by the primary circulation kettle 2 and overflows to the secondary circulation kettle 7. Unreacted hydrogen chloride rises to the first chlorination tower condenser 4 through the kettle top gas phase pipeline, and non-condensable gas is discharged to the tail gas outlet.

[0041] Secondary Reaction Stage: A secondary circulation pump 10 pumps the liquid material from the secondary circulation kettle 7 through the secondary circulation heat exchanger 8, then feeds it from the top of the tower. After being evenly distributed by a distributor, it enters the packing section or enters the lower tray via a downcomer. Hydrogen chloride (HCl) enters the secondary chlorination tower 6 through HCl inlet 62. The rising HCl gas and descending liquid form a countercurrent within the tower, ensuring full contact between the liquid material and HCl. The chlorination reaction product is buffered in the secondary circulation kettle and discharged through product outlet 71. Unreacted HCl and generated water are then transferred to the secondary chlorination tower condenser 9 via the overhead vapor phase line. Dichloropropanol, HCl, and water are discharged with the distillate, and unreacted HCl is returned to the primary chlorination tower 1. The secondary chlorination tower condenser 9 removes generated water promptly, increasing the forward reaction rate and glycerol conversion.

[0042] Reaction effect: Chlorination tower reaction temperature: 125℃, reaction pressure: normal pressure, distillate: 35% dichloropropanol, 30% hydrogen chloride, 35% water; produced liquid: 73% dichloropropanol, 18% monochloropropylene glycol, 4% glycerol, 5% catalyst.

[0043] Example 2:

[0044] The similarities between this embodiment and embodiment 1 are not repeated here, but the differences are as follows:

[0045] The primary chlorination tower 1 and the secondary chlorination tower 6 include a shell 13, a gas inlet 14 and a liquid outlet 15 at the lower end of the shell 13, a gas outlet 16 and a first liquid inlet 17 at the upper end of the shell 13, and a second liquid inlet 18 in the middle of the shell 13. The shell 13 is provided with a packing section 19, a liquid distributor 20, and a liquid collector 21 in order from bottom to top. The second liquid inlet 18 is located above the liquid collector 21, and the packing section is two or more.

[0046] Example 3:

[0047] The similarities between this embodiment and embodiment 1 are not repeated here, but the differences are as follows:

[0048] Depend on Figure 3 As shown, the primary circulation kettle is connected to the connecting pipes of the secondary circulation heat exchanger 8 and the secondary circulation pump 10.

[0049] Example 4:

[0050] The similarities between this embodiment and embodiment 3 are not repeated here, and the differences are as follows:

[0051] Depend on Figure 4 As shown, the process comprises a primary reaction unit, a secondary reaction unit, and a tertiary reaction unit. The tertiary reaction unit has the same composition as the secondary reaction unit, with hydrogen chloride entering from a tertiary reaction tower. The tertiary chlorination tower operates at a temperature of 100-140°C, a pressure of -0.05-0.1 MPa, a residence time of 6-12 hours, and a feedstock hydrogen chloride content of ≥90%.

[0052] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production device for preparing dichloropropane by glycerol tower chlorination, characterized in that: It includes 2 or more reaction units, each of which is equipped with a chlorination tower; The reaction unit includes a primary reaction unit and a secondary reaction unit. The primary reaction unit includes a primary chlorination tower, a primary circulation kettle connected to the primary chlorination tower, a primary circulation heat exchanger connected between the primary chlorination tower and the primary circulation kettle, and a primary chlorination tower condenser is provided on the top of the primary chlorination tower; The secondary reaction unit comprises a secondary chlorination tower, a secondary circulation kettle connected to the secondary chlorination tower, and a secondary circulation heat exchanger connected between the secondary chlorination tower and the secondary circulation kettle. A secondary chlorination tower condenser is provided on the top of the secondary chlorination tower.

2. The production unit for preparing dichloropropane by glycerol tower chlorination according to claim 1, wherein: The primary circulation kettle is connected to the secondary circulation kettle, or is connected to the connecting pipe between the secondary circulation heat exchanger and the secondary circulation kettle; The secondary chlorination tower condenser is connected to the bottom of the first-level chlorination tower; A raw material inlet is provided at the top of the first-level chlorination tower, a hydrogen chloride inlet is provided at the bottom of the second-level chlorination tower, and a distillate outlet is provided on the condenser of the second-level chlorination tower.

3. The production unit for preparing dichloropropane by glycerol tower chlorination according to claim 1, wherein: The bottoms of the primary chlorination tower and the secondary chlorination tower are both provided with liquid outlets. The liquid outlet of the primary chlorination tower is connected to the primary circulation kettle, and the liquid outlet of the secondary chlorination tower is connected to the secondary circulation kettle.

4. The production unit for preparing dichloropropane by glycerol tower chlorination according to claim 1, wherein: The primary circulation heat exchanger is connected to the middle of the primary chlorination tower, the secondary circulation heat exchanger is connected to the upper part of the secondary chlorination tower, and the primary chlorination tower condenser is provided with a tail gas outlet.

5. The production device for preparing dichloropropane by glycerol tower chlorination according to claim 1, wherein: A primary circulation pump is further provided between the primary circulation kettle and the primary circulation heat exchanger, and a secondary circulation pump is further provided between the secondary circulation kettle and the secondary circulation heat exchanger.

6. The production device for preparing dichloropropane by glycerol tower chlorination according to claim 1, characterized in that: The secondary circulation kettle is provided with a produced liquid discharge port.

7. The production device for preparing dichloropropane by glycerol tower chlorination according to claim 1, characterized in that: The primary chlorination tower and the secondary chlorination tower include a shell, a gas inlet and a liquid outlet at the lower end of the shell, a gas outlet and a first liquid inlet at the upper end of the shell, and a second liquid inlet at the middle part of the shell.

8. The production device for preparing dichloropropane by glycerol tower chlorination according to claim 7, characterized in that: The shell is provided with a packing section, a liquid distributor and a liquid collector in sequence from bottom to top, and the second liquid inlet is located at the upper part of the liquid collector; The number of the packing sections is 2 or more.

9. The production device for preparing dichloropropane by glycerol tower chlorination according to claim 1, characterized in that: The reaction temperature of the first-level chlorination tower and the second-level chlorination tower is 100-140° C., the reaction pressure is -0.05-0.1 MPa, and the residence time is 6-12 hours.

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