Separating device for cellulose ether production

Abstract

The utility model discloses a separation device for cellulose ether production in the technical field of cellulose ether production, which comprises a storage tank, a drain pipe externally connected to the bottom of the storage tank, a discharge valve arranged on the drain pipe, a densimeter arranged on the drain pipe and used for detecting contents in the drain pipe, and a first guide pipe and a second guide pipe connected to the drain pipe. In the flowing direction of contents in the drainage pipe, the connecting point of the first guide pipe and the drainage pipe is located behind the densimeter, the connecting point of the second guide pipe and the drainage pipe is located behind the densimeter, a first valve is arranged on the first guide pipe, and a second valve is arranged on the second guide pipe. The density difference of solvent and water is utilized, the densimeter for detecting contents in the drainage pipe is arranged on the drainage pipe to detect the density of liquid so as to determine whether the liquid in the drainage pipe is water or solvent, accurate water distribution is achieved, the water distribution effect is improved, the situation that the water content in the solvent is too high, and product quality is affected can be avoided, and production efficiency is improved. The energy consumption increase caused by excessive water separation of the solvent is also avoided.

Description

Technical Field

[0001] This utility model relates to the field of cellulose ether production technology, and in particular to a separation device for cellulose ether production. Background Technology

[0002] Hydroxypropyl methylcellulose ether (hereinafter referred to as HPMC) is a non-ionic cellulose ether widely used in construction, medicine, food, daily chemical industry, ceramics and many other fields. The traditional production process of HPMC usually adopts the solvent method. Cotton or wood cellulose powder is added to a mixed solvent of toluene and isopropanol (toluene about 70-90%, isopropanol about 10-30%), and sodium hydroxide is added for alkalization. Then, an etherifying agent (chloromethane and propylene oxide) is added to carry out the etherification reaction. After the reaction is completed, the mixed solvent is recovered and recycled to obtain crude HPMC product. The crude HPMC product is then filtered and washed, and the washed product is dried and pulverized to obtain the finished HPMC product.

[0003] Recycled solvents typically contain a significant amount of water and require settling and dehydration before reuse. Incomplete dehydration leads to excessively high water content in the solvent, reducing the alkali concentration in the HPMC production process and consequently affecting HPMC product quality. Since the recycled water separated from the solvent contains a small amount of solvent, distillation is necessary to recover the solvent components. Excessive dehydration increases energy consumption.

[0004] Currently, the most common method for solvent water separation in HPMC production processes is to separate water from the bottom outlet pipe of the storage tank after settling. The pipe is equipped with a discharge valve and a sight glass or sampling port. The completeness of water separation is determined by observing the appearance of the solvent or by taking a sample. This method requires manual intervention, resulting in a low level of automation. Furthermore, the solvent tank area is typically a major hazard source, and frequent manual operation may increase safety risks. Alternatively, excessive water separation can be used to ensure effective separation, but this carries away solvent, increasing energy consumption in the recycled water distillation process. Utility Model Content

[0005] To address the technical problem of poor water separation efficiency in existing devices, this invention provides a separation device for cellulose ether production that improves automation and enhances water separation efficiency.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A separation device for the production of cellulose ethers includes a storage tank with a drain pipe connected to the bottom of the tank. The drain pipe is equipped with a discharge valve and a density meter for detecting the contents of the drain pipe. A first conduit and a second conduit are connected to the drain pipe. Along the flow direction of the contents of the drain pipe, the connection point between the first conduit and the drain pipe is located after the density meter, and the connection point between the second conduit and the drain pipe is located after the density meter. A first valve is installed on the first conduit, and a second valve is installed on the second conduit.

[0008] Furthermore, it also includes a return pipe, a pump body, and a condenser. One end of the return pipe is connected to the drain pipe, and the other end is connected to the top of the storage tank. The pump body is installed on the drain pipe. Along the flow direction of the contents of the drain pipe, the connection point between the return pipe and the drain pipe is located after the pump body. A switch valve is installed on the return pipe. The return pipe includes a first section pipe and a second section pipe. The condenser is located between the first section pipe and the second section pipe. Both the first section pipe and the second section pipe are connected to the condenser.

[0009] Furthermore, the discharge valve, the first valve, the second valve, and the on / off valve are all electric valves.

[0010] Furthermore, the densitometer is an insertion type, and a buffer device for controlling the flow rate is installed on the drain pipe.

[0011] Furthermore, the density meter is a tubular density meter.

[0012] Furthermore, a thermometer is installed on the storage tank.

[0013] The beneficial effects of this utility model are:

[0014] This solution utilizes the density difference between solvent and water by installing a density meter on the drain pipe to detect the density of the liquid inside, thus determining whether the liquid in the drain pipe is water or solvent. This enables automated control of the water separation process, achieving accurate water separation, improving the water separation effect, and preventing excessive water content in the solvent from affecting product quality. It also avoids increased energy consumption caused by excessive solvent water separation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the separation device for cellulose ether production according to this utility model;

[0016] The markings in the diagram are as follows: 1-Storage tank, 2-Drain pipe, 3-Discharge valve, 4-Density meter, 5-First conduit, 6-Second conduit, 7-First valve, 8-Second valve, 9-Return pipe, 10-Condenser, 11-Pump body, 12-Switch valve, 13-Thermometer. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the present invention will be further described below with reference to the accompanying drawings.

[0018] First, it should be stated that the technical solutions of the embodiments of this application are clearly and completely described. The described embodiments are only some of the embodiments of this application, and not a limitation of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] In the description of this utility model, it should be understood that the terms "first", "second", "upper", "lower", "left", "right", "inner", "outer", "axial" or "radial" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and are not intended to indicate or imply that the device or element referred to must have a specific orientation structure and operation. Therefore, they should not be construed as limitations on this utility model.

[0020] It should be noted that, in this utility model, unless otherwise explicitly specified and limited, the terms "connection" and "fixation," etc., should be interpreted broadly. For example, "fixation" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Reference Figure 1 This utility model provides a separation device for the production of cellulose ethers.

[0022] In an embodiment of this solution, the separation device for cellulose ether production includes a storage tank 1, a drain pipe 2 connected to the bottom of the storage tank 1, a discharge valve 3 installed on the drain pipe 2, a densitometer 4 for detecting the contents of the drain pipe 2 installed on the drain pipe 2, a first conduit 5 and a second conduit 6 connected to the drain pipe 2, and along the flow direction of the contents of the drain pipe 2, the connection point between the first conduit 5 and the drain pipe 2 is located after the densitometer 4, the connection point between the second conduit 6 and the drain pipe 2 is located after the densitometer 4, a first valve 7 is installed on the first conduit 5, and a second valve 8 is installed on the second conduit 6.

[0023] Furthermore, it also includes a return pipe 9, a pump body 11, and a condenser 10. One end of the return pipe 9 is connected to the drain pipe 2, and the other end is connected to the top of the storage tank 1. The pump body 11 is installed on the drain pipe 2. Along the flow direction of the contents of the drain pipe 2, the connection point between the return pipe 9 and the drain pipe 2 is located after the pump body 11. A switch valve 12 is installed on the return pipe 9. The return pipe 9 includes a first section pipe and a second section pipe. The condenser 10 is located between the first section pipe and the second section pipe. Both the first section pipe and the second section pipe are connected to the condenser 10.

[0024] The working process of one embodiment is as follows:

[0025] The solvent inside storage tank 1 is cooled down. The recovered solvent is usually at a relatively high temperature, which may range from 50 to 100°C depending on the actual process. Since the solubility of water in the solvent increases with increasing temperature, excessively high solvent temperatures are not conducive to water separation. Therefore, the solvent needs to be cooled before water separation.

[0026] First, open the discharge valve 3 and start the pump body 11. After the pump body 11 is running normally, open the switch valve 12. The solvent is pumped through the pump body 11 to the condenser 10, and after cooling, it returns to the storage tank 1. The condenser 10 can use circulating water, chilled water, or other cooling methods. The structure of the condenser 10 can be plate type, tubular type, or other structures. There are no special limitations here, as long as it can achieve the purpose of cooling the solvent. As the solvent circulates and cools, the temperature value of the solvent inside the storage tank 1 measured by the thermometer 13 gradually decreases. When the temperature value reaches the set value, the cooling of the solvent ends. Close the switch valve 12 and the pump body 11, and the solvent begins to settle.

[0027] Then, after a period of settling, the water and solvent separate into layers quite thoroughly. The upper layer in storage tank 1 is mainly a mixture of toluene and isopropanol, while the lower layer is mainly water. The required settling time depends on the solvent temperature and the alcohol content in the solvent, and needs to be determined based on the actual process conditions.

[0028] Finally, the solvent is separated into water. The discharge valve 3 is opened, and the pump 11 is started. After the pump 11 is running normally, the first valve 7 is opened. The recovered water is transported to the recovery water tank via the pump 11 and the first conduit 5. During the separation process, the density meter 4 continuously monitors the liquid density in the drain pipe 2. The recovered water (mainly water, containing a small amount of alcohol and trace amounts of toluene) has a density close to 1 g / mL, and the solvent (approximately 70-90% toluene, approximately 10-30% isopropanol, methanol, and other alcohols, and a small amount of water) has a density of approximately 0.85-0.9 g / mL.

[0029] At the beginning of the water separation, the density value of the liquid measured by the hydrometer 4 is relatively high. In the later stage of water separation, the liquid is a mixture of recycled water and solvent. At this time, the liquid density measured is between the densities of the two. After the water separation is complete, the liquid density measured is the solvent density. At this time, the water separation ends, the first valve 7 is closed, the second valve 8 is opened, and the solvent is transported to the solvent tank through the second conduit 6.

[0030] In one specific embodiment, the operation steps are as follows:

[0031] First, the solvent inside the storage tank 1 is cooled down. The solvent temperature is 72℃ and needs to be cooled down. The discharge valve 3 is opened and the pump body 11 is turned on. After the pump body 11 is running normally, the switch valve 12 is opened. The solvent is transported to the condenser 10 through the pump body 11. After being cooled, it returns to the storage tank 1. The condenser 10 is cooled by circulating water.

[0032] As the solvent circulates and cools, the temperature of the solvent inside the storage tank 1 is measured by thermometer 13 and gradually decreases. When the temperature reaches 35°C, the cooling of the solvent ends. The switch valve 12 and pump body 11 are closed, and the solvent begins to settle. After 2 hours of settling, the solvent has finished settling.

[0033] Finally, the solvent is separated into water. The discharge valve 3 is opened and the pump body 11 is started. After the pump body 11 is running normally, the first valve 7 is opened. The recycled water is transported to the recycled water tank through the pump body 11 and the first conduit 5. During the water separation process, the density meter 4 continuously detects the liquid density in the drain pipe 2.

[0034] At the beginning of the water separation, the density of the liquid measured by the hydrometer 4 is 0.98 g / ml. In the later stage of water separation, the liquid is a mixture of recycled water and solvent, and the liquid density measured at this time is 0.90-0.95 g / ml. After the water separation is complete, the liquid density is measured to be 0.87 g / ml. At this time, the water separation ends, the first valve 7 is closed, the second valve 8 is opened, and the solvent is transported to the solvent tank through the second conduit 6.

[0035] The densitometer 4 can be a pipe-type densitometer, which can accurately measure liquid density without a buffer device. Alternatively, an insertion-type densitometer can be used, in which case a buffer device to control the liquid flow rate needs to be installed on the drain pipe 2 to ensure that the liquid flow rate meets the measurement requirements of the insertion-type densitometer. This buffer device can be a buffer valve, a liquid flow controller, or a regulating valve; no specific limitation is made, as long as it achieves the purpose of controlling the liquid flow rate. Besides the pipe-type and insertion-type densitometers mentioned above, other types of densitometers 4 can also be used, as long as they can measure the liquid density in real time.

[0036] In the embodiments of this solution, the discharge valve 3, the first valve 7, the second valve 8, and the switch valve 12 are preferably electric valves. In addition, manual shut-off valves, pneumatic valves, or other mechanical valves can also be selected.

[0037] In an embodiment of this solution, a thermometer 13 is installed on the storage tank 1.

Claims

1. A separation device for the production of cellulose ethers, comprising a storage tank (1), a drain pipe (2) connected to the bottom of the storage tank (1), and a discharge valve (3) provided on the drain pipe (2), characterized in that: A density meter (4) for detecting the contents of the drain pipe (2) is installed on the drain pipe (2). A first conduit (5) and a second conduit (6) are connected to the drain pipe (2). Along the flow direction of the contents of the drain pipe (2), the connection point of the first conduit (5) and the drain pipe (2) is located after the density meter (4), and the connection point of the second conduit (6) and the drain pipe (2) is located after the density meter (4). A first valve (7) is installed on the first conduit (5), and a second valve (8) is installed on the second conduit (6).

2. The separation apparatus for cellulose ether production as described in claim 1, characterized in that: It also includes a return pipe (9), a pump body (11) and a condenser (10). One end of the return pipe (9) is connected to the drain pipe (2) and the other end is connected to the top of the storage tank (1). The pump body (11) is installed on the drain pipe (2). Along the flow direction of the contents of the drain pipe (2), the connection point between the return pipe (9) and the drain pipe (2) is located after the pump body (11). A switch valve (12) is installed on the return pipe (9). The return pipe (9) includes a first section pipe and a second section pipe. The condenser (10) is located between the first section pipe and the second section pipe. Both the first section pipe and the second section pipe are connected to the condenser (10).

3. The separation device for cellulose ether production as described in claim 2, characterized in that: the discharge... Valve (3), first valve (7), second valve (8) and switch valve (12) are all electric valves.

4. The separation apparatus for cellulose ether production as described in claim 1, characterized in that: density The meter (4) is an insertion type density meter, and the drain pipe (2) is equipped with a buffer device to control the flow rate.

5. The separation apparatus for cellulose ether production as described in claim 1, characterized in that: density The meter (4) is a pipe-type density meter.

6. The separation apparatus for cellulose ether production as described in any one of claims 1-5, characterized in that: A thermometer (13) is installed on the storage tank (1).

Images