Urotropine concentration device

Abstract

The utility model belongs to the technical field of separation devices, and particularly relates to a urotropine concentration device which comprises a falling film evaporator, a circulating evaporation tank connected with the falling film evaporator, a plate heat exchanger connected with the bottom of the circulating evaporation tank, a delivery pump connected with the bottom of the plate heat exchanger and connected with the upper portion of the circulating evaporation tank. A sprayer and a plurality of falling film pipes are arranged in the falling film evaporator, the top of the falling film evaporator is connected with a negative pressure pump, a heat exchange sleeve is arranged outside the falling film evaporator, a plurality of baffle plates are obliquely arranged in the heat exchange sleeve, and a stirrer is arranged in the circulating evaporation tank. The problems of high energy consumption, low efficiency and high decomposition risk in urotropine concentration are solved by controlling the temperature in the vacuum falling film evaporation and circulating evaporation processes.

Description

Technical Field

[0001] This utility model belongs to the field of separation device technology, specifically relating to a hexamethylenetetramine concentration device. Background Technology

[0002] Urotropine is produced by the condensation reaction of formaldehyde and ammonia (or liquid ammonia). It has a cage-like structure, is a white crystalline powder or colorless, lustrous crystals, is easily soluble in water, and its aqueous solution is weakly alkaline. It decomposes to produce formaldehyde. Urotropine has a wide range of applications, including the production of synthetic resins, the pharmaceutical industry, the rubber and textile industries, and can also be used as a synthetic framework.

[0003] Typical traditional process steps include condensing formaldehyde solution and ammonia water in a reactor, followed by evaporation and concentration, crystallization, centrifugation and drying. Concentration is a high-energy-consuming and clog-prone step in the production of hexamethylenetetramine. Efficient and anti-scaling concentration technology is key. Traditional hexamethylenetetramine concentration processes, such as single-effect evaporation, have problems such as high energy consumption, low efficiency and difficulty in temperature control. Single-effect evaporation requires continuous steam input, and energy consumption accounts for 30%-40% of the production cost. When concentrating low-concentration solutions, the heat transfer coefficient decreases, the evaporation rate is slow, and high temperature can easily lead to the decomposition of hexamethylenetetramine to generate byproducts such as trimethylamine. Utility Model Content

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a hexamethylenetetramine concentration device that achieves dual-effect concentration, improves the concentration efficiency of hexamethylenetetramine, and reduces reaction energy consumption.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] The hexamethylenetetramine concentration device of this utility model includes a falling film evaporator, a circulating evaporator connected to the falling film evaporator, a plate heat exchanger connected to the bottom of the circulating evaporator, a feed pump connected to the bottom of the plate heat exchanger, the feed pump connected to the upper part of the circulating evaporator, a sprayer and several falling film tubes installed inside the falling film evaporator, a negative pressure pump connected to the top of the falling film evaporator, a heat exchange jacket installed outside the falling film evaporator, several baffles installed at an incline inside the heat exchange jacket, and a stirrer installed inside the circulating evaporator.

[0007] in:

[0008] The sprayer is connected to a raw material pipeline and is located above the falling film pipe.

[0009] The angle between the baffle plate and the heat exchange jacket in the vertical direction is 10-20°.

[0010] The falling film tubes are all vertically arranged inside the falling film evaporator, and the sidewalls of the falling film tubes are connected to each other.

[0011] The falling film tube has several through holes spaced apart on its sidewall.

[0012] The agitator includes a side scraper and a bottom stirring plate, and a motor is connected to the top of the agitator through the circulating evaporator.

[0013] The circulating evaporator is provided with a steam outlet at the top, which is connected to the upper part of the heat exchange jacket. A vacuum pump is installed between the steam outlet and the heat exchange jacket.

[0014] A demister is installed at the steam outlet.

[0015] The circulating evaporator is equipped with a discharge pipe at the bottom.

[0016] The plate heat exchanger is provided with a heat exchange shell on its outer side.

[0017] The falling film tube is made of graphite-modified material.

[0018] The beneficial effects of this utility model are:

[0019] This invention solves the problems of high energy consumption, low efficiency, and high decomposition risk in hexamethylenetetramine concentration by controlling the temperature during vacuum falling film evaporation and circulating evaporation. The surface area of ​​the hexamethylenetetramine reaction liquid continuously increases in the falling film evaporator, which can promote rapid evaporation of water. Furthermore, the structure of the falling film tube can also enable the rapid separation of evaporated water from the reaction liquid. During the circulating evaporation process, the stirrer can prevent hexamethylenetetramine from crystallizing on the inner wall of the circulating evaporator, which would affect the hexamethylenetetramine yield. The secondary steam during evaporation can also be used for heat exchange in the falling film evaporator, realizing full utilization of thermal energy. Concentration at low temperature can also prevent the decomposition of hexamethylenetetramine, thus combining high efficiency, economy, and environmental protection.

[0020] This invention effectively solves the two core problems of scaling and thermal decomposition in the concentration process of hexamethylenetetramine, ensuring continuous and stable production, high product purity, and low operating energy consumption. Compared with traditional single-effect evaporation, this invention reduces steam consumption from 1.5t / t to about 0.9t / t, concentration time from 10h to about 5h, and product purity from 99.0% to about 99.5%. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the falling film tube structure of this utility model. Figure 1 ;

[0023] Figure 3 This is a schematic diagram of the falling film tube structure of this utility model. Figure 2 ;

[0024] Figure 4 This is a schematic diagram of the heat exchanger structure of this utility model;

[0025] In the diagram: 1. Falling film evaporator; 2. Circulating evaporator; 3. Plate heat exchanger; 4. Feed pump; 5. Agitator; 6. Negative pressure pump; 7. Sprayer; 8. Falling film tube; 9. Heat exchange jacket; 10. Raw material pipeline; 11. Discharge pipeline; 12. Vacuum pump; 13. Baffle plate; 201. Steam outlet; 202. Demister screen; 301. Heat exchange shell; 501. Scraper; 502. Agitator plate; 801. Through hole. Detailed Implementation

[0026] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0027] Example 1

[0028] like Figure 1-4 As shown, the hexamethylenetetramine concentration device includes a falling film evaporator 1, a circulating evaporator 2 connected to the falling film evaporator 1, a plate heat exchanger 3 connected to the bottom of the circulating evaporator 2, a feed pump 4 connected to the bottom of the plate heat exchanger 3, the feed pump 4 connected to the upper part of the circulating evaporator 2, a sprayer 7 and several falling film tubes 8 installed inside the falling film evaporator 1, a negative pressure pump 6 connected to the top of the falling film evaporator 1, a heat exchange jacket 9 installed outside the falling film evaporator 1, several baffles 13 installed at an incline inside the heat exchange jacket 9, and a stirrer 5 installed inside the circulating evaporator 2.

[0029] The sprayer 7 is connected to the raw material pipe 10 and is located above the falling film pipe 8.

[0030] The angle between the baffle plate 13 and the heat exchange jacket 9 in the vertical direction is 10-20°.

[0031] Several falling film tubes 8 are vertically arranged inside the falling film evaporator 1, and the side walls of the falling film tubes 8 are connected to each other.

[0032] Several through holes 801 are provided at intervals on the side wall of the falling film tube 8.

[0033] The agitator 5 includes a side scraper 501 and a bottom stirring plate 502, and a motor is connected to the top of the agitator 5 through the circulating evaporator 2.

[0034] The top of the circulating evaporator 2 is provided with a steam outlet 201, which is connected to the upper part of the heat exchange jacket 9. A vacuum pump 12 is provided between the steam outlet 201 and the heat exchange jacket 9.

[0035] A demister 202 is installed at the steam outlet 201.

[0036] The bottom of the circulating evaporator 2 is equipped with a discharge pipe 11.

[0037] A heat exchange shell 301 is provided on the outside of the plate heat exchanger 3.

[0038] Working principle and process:

[0039] The reaction solution containing hexamethylenetetramine is transported to the falling film evaporator 1 and evenly sprayed onto the top of several falling film tubes 8 by sprayer 7. Hot water is added to the heat exchange jacket 9, with a pressure of 0.5 MPa inside. The hot water flows through the heat exchange jacket 9 via baffles 13, cascading in the same direction. The baffles 13 enhance the heat transfer efficiency of the heat exchange jacket 9 to the falling film evaporator 1, causing the temperature inside the evaporator 1 to continuously rise from 50-60℃ to 65-70℃. The negative pressure pump 6 is activated to continuously reduce the internal pressure of the falling film evaporator 1 to -0.05 MPa. The reaction solution flows continuously through the falling film tubes 8 at a velocity of 1.2 m / s, and the water inside the reaction solution is continuously separated and... The vapor is removed by evaporation under the action of the negative pressure pump 6. The through hole 801 on the falling film tube 8 can promote the separation of the evaporated water from the reaction liquid. The vapor rises continuously and is drawn out by the negative pressure pump 6. Then, the reaction liquid flowing to the bottom of the falling film evaporator 1 is transported to the circulating evaporator 2. The reaction temperature is raised from 65-70℃ to 80℃ by the plate heat exchanger 3. The motor is turned on so that the stirrer 5 is stirred at a speed of 300rpm. The vacuum pump 12 continuously draws out the vapor evaporated in the circulating evaporator 2 and transports it to the heat exchange jacket 9 for falling film evaporation. The vacuum pump 12 reduces the pressure in the circulating evaporator 2 to -0.08MPa, further improving the evaporation effect. The concentrated hexamethylenetetramine solution can be discharged through the discharge pipe 11.

Claims

1. A hexamethylenetetramine concentration apparatus, comprising a falling film evaporator (1), characterized in that, The falling film evaporator (1) is connected to the circulating evaporator (2). The bottom of the circulating evaporator (2) is connected to the plate heat exchanger (3). The bottom of the plate heat exchanger (3) is connected to the feed pump (4). The feed pump (4) is connected to the upper part of the circulating evaporator (2). The falling film evaporator (1) is equipped with a sprayer (7) and several falling film tubes (8). The top of the falling film evaporator (1) is connected to a negative pressure pump (6). The outside of the falling film evaporator (1) is equipped with a heat exchange jacket (9). Several baffles (13) are inclined inside the heat exchange jacket (9). The circulating evaporator (2) is equipped with a stirrer (5).

2. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, The sprayer (7) is connected to the raw material pipeline (10), and the sprayer (7) is located above the falling film pipe (8).

3. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, The angle between the baffle (13) and the heat exchange jacket (9) in the vertical direction is 10-20°.

4. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, Several falling film tubes (8) are vertically installed inside the falling film evaporator (1), and the side walls of the several falling film tubes (8) are connected to each other.

5. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, Several through holes (801) are provided at intervals on the side wall of the falling film tube (8).

6. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, The agitator (5) includes a scraper (501) on the side and a stirring plate (502) at the bottom. The top of the agitator (5) is connected to a motor through the circulating evaporator (2).

7. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, The top of the circulating evaporator (2) is provided with a steam outlet (201), which is connected to the upper part of the heat exchange jacket (9). A vacuum pump (12) is provided between the steam outlet (201) and the heat exchange jacket (9).

8. The hexamethylenetetramine concentration apparatus according to claim 7, characterized in that, A demister (202) is installed at the steam outlet (201).

9. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, The bottom of the circulating evaporator (2) is equipped with a discharge pipe (11).

10. The hexamethylenetetramine concentration apparatus according to claim 1, characterized in that, A heat exchange shell (301) is provided on the outside of the plate heat exchanger (3).

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