Filter system for removing ammonium chloride in the synthesis of butylamine hydrochloride

Abstract

The utility model relates to medical intermediate synthetic equipment technical field discloses a kind of filter systems of exempting from to wash out ammonium chloride in the synthesis process of butylamidine hydrochloride, including filter and counterflow pulse backwash tank, filter includes the filter upper end socket, filter body and filter lower end socket of detachable connection each other;Annular clearance is left on the inner wall of filter and is equipped with metal sintered filter screen, and inside is equipped with pressure filtration purging nitrogen insertion pipe.Counterflow pulse backwash tank is equipped with air inlet control valve, backwash control valve and liquid level meter, and connect with butylamidine hydrochloride methanol supernatant storage tank after through flowmeter, liquid discharge control valve, and signal connection is carried out with air inlet control valve, liquid discharge control valve and backwash control valve of liquid level meter, to realize liquid level interlock control.The utility model realizes the online production process of efficient filtration, backwash and full-closed beating, deslagging, and does not need manual disassembly and washing, eliminates the environmental protection safety hidden danger of methanol volatilization.

Description

Technical Field

[0001] This utility model belongs to the technical field of pharmaceutical intermediate synthesis equipment, specifically relating to a filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride. Background Technology

[0002] Butyramidine hydrochloride, CAS Registry No.: 3020-81-3, belongs to the aliphatic amidine hydrochloride class. It is readily soluble in water and methanol, but sparingly soluble in acetone and alkane solvents. Its aqueous solution is weakly acidic. It can undergo cyclization, acylation, and alkylation reactions, and is a core intermediate raw material in fine chemical and veterinary drug synthesis. Butyramidine hydrochloride is a key intermediate in the anticoccidial raw material amproline hydrochloride, and is an essential raw material in the industry chain. Amproline is widely used for the prevention and control of coccidiosis in livestock and poultry such as chickens, ducks, and rabbits. It has the characteristics of low toxicity and low likelihood of inducing drug resistance, and is a mainstream veterinary drug for large-scale farming.

[0003] The ammonolysis method for amidine nitrile alcohols was first developed by fine chemical laboratories in Europe and America in 1940. In the 1950s, foreign pharmaceutical companies first achieved pilot-scale production of butamidine hydrochloride to support anticoccidial drugs for livestock and poultry. The core reaction mechanism was included in authoritative organic synthesis journals such as Heterocycles, laying the foundation for the industry's basic process framework. The mainstream industry approach uses n-butadiene-nitrile (NBR) as the starting material. Dry hydrogen chloride gas is introduced into the NBR system at low temperature, causing the nitrile group to undergo addition to form an intermediate of butadiene-iminomethyl ether hydrochloride. Then, a saturated ammonia-methanol solution is prepared and added dropwise to the intermediate system at low temperature. Ammonolysis is then performed under pressure, and the imino ether undergoes a substitution reaction with ammonia to form butadiene. Hydrochloric acid in the system is simultaneously salted. Finally, post-treatment purification is carried out. The ammonolysis reaction solution is placed in a "three-in-one" filter to remove a large amount of the byproduct ammonium chloride. The methanol solution of butadiene-imino ether hydrochloride obtained by filtration is sent to a butadiene-imino ether hydrochloride crystallization kettle for evaporation to recover methanol. The concentrated butadiene-imino ether hydrochloride methanol solution is then filtered again to remove a small amount of ammonium chloride.

[0004] In the secondary filtration process for removing ammonium chloride during the post-processing purification stage, due to the small amount of ammonium chloride, "three-in-one" filters cannot be used. Only bag filters or sintered rod filters can be used. However, these filters need to be disassembled and cleaned after failure, resulting in a poor operating environment. Furthermore, due to the presence of a large amount of volatile methanol gas, safety and environmental protection are difficult to guarantee. This is also one of the most environmentally challenging processes in the production of this product. Therefore, improvements to the existing technology are necessary. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride that is simple in structure and easy to use.

[0006] To solve the above-mentioned technical problems, this utility model provides a filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride, comprising: a filter and a countercurrent pulse backwash tank. The filter includes an upper filter head, a filter body, and a lower filter head that are detachably connected from top to bottom. A sintered metal filter screen is provided around the inner wall of the filter, and the sintered metal filter screen is fixedly connected to the inner wall of the filter with an annular gap. A pressure filter purging nitrogen insertion pipe is provided inside the filter, and the bottom opening of the lower filter head is a slag discharge port. The lower outlet of the pressure filter purging nitrogen insertion pipe is directly opposite the slag discharge port. The countercurrent pulse backwash tank is equipped with an upper drain port, an air inlet control valve at the top, and a backwash control valve at the bottom. A level gauge is installed on the tank body. The filter is connected to the backwash control valve. The upper drain port is connected to the butamidine methanol clear liquid storage tank through a flow meter and a drain control valve. The level gauge is connected to the air inlet control valve, the drain control valve, and the backwash control valve as signals to achieve interlocked level control.

[0007] This invention represents an improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride: The lower part of the side wall of the filter body is provided with a second drain and backflush port; The filter's lower end cap is funnel-shaped, and the lower part of the side wall is provided with a first drain and backflush port; The sintered metal filter screen includes a second sintered metal filter screen surrounding the inner wall of the filter body and a first sintered metal filter screen surrounding the inner wall of the lower end cap of the filter; one end of the first drain and backflushing port is connected to the annular gap between the first sintered metal filter screen and the lower end cap of the filter, and one end of the second drain and backflushing port is connected to the annular gap between the second sintered metal filter screen and the filter body; the other ends of the first drain and backflushing port and the second drain and backflushing port are connected to the backflushing control valve through a tee.

[0008] As a further improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model: The upper end cap of the filter is connected to the filter body through a first flange, and the filter body is connected to the lower end cap of the filter through a second flange. A slag discharge valve is provided below the slag discharge port, and the slag discharge port and the slag discharge valve are connected through a third flange.

[0009] As a further improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model: The filter head is equipped with a spray valve, a nitrogen valve, a feed valve, a first pressure gauge, and a safety valve. A sprayer is installed inside the filter head, which is fixedly connected to the filter head and then connected to the methanol storage tank via a methanol transfer pump after passing through the spray valve.

[0010] As a further improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model: Nitrogen gas is connected to the inner cavity of the counter-current pulse backwash tank through the inlet control valve, and to the inner cavity of the filter through the nitrogen gas valve; The butamidine hydrochloride methanol solution storage tank is connected to the filter cavity via a butamidine hydrochloride methanol solution delivery pump and a feed valve.

[0011] As a further improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model: The gap between the second metal sintered filter screen and the inner wall of the filter body is 5-10 mm; The gap between the first metal sintered filter screen and the inner wall of the lower end cap of the filter is 5-10mm.

[0012] As a further improvement to the filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model: The filter upper end cap has a transmission screw at its top center. The lower end of the transmission screw is fixedly connected to the filter upper end cap, and the upper part passes through the end of the horizontally bent section of the L-shaped support and is threadedly connected to the opening and closing handwheel. At the same time, the opening and closing handwheel is rotatably connected to the L-shaped support and is axially limited. A transverse support arm is fixedly connected to the outer side wall of the filter body, and the vertical support section of the L-shaped support is pivotally connected to the transverse support arm via a rotating shaft.

[0013] The beneficial effects of this utility model are mainly reflected in: 1. Strong corrosion resistance: The main components and internal filter screen are made of 2205 duplex steel, which can effectively resist the strong acid and high concentration of chloride ions in the butamidine hydrochloride synthesis system. Moreover, no water is needed for cleaning during use, which greatly extends the service life of the filter and filter screen.

[0014] 2. High-efficiency filtration and backwashing: By setting a sintered metal filter screen in the filter body and the lower end of the filter with a gap of 5-10mm behind it, and in conjunction with the drain and backwash port and the countercurrent pulse backwash tank, it can not only efficiently intercept solid ammonium chloride slag, but also use the clear liquid generated by filtration as the backwash medium. Under the pressure of pressurized nitrogen, a strong pulse impact force is formed from the outside to the inside, which can instantly peel off the solid ammonium chloride attached to the inside of the filter screen, so that the filtration flow can be efficiently restored online without disassembly and shutdown.

[0015] 3. Closed-loop circulation without disassembly and cleaning: High-pressure nitrogen purging is used to dry the filter cake, followed by atomized methanol spraying from a sprayer to wash the solid ammonium chloride into a slurry. The resulting free-flowing ammonium chloride-methanol slurry is then sealed and forced into an external ammonium hydrolysis reactor through a slag discharge valve. This achieves zero leakage of volatile gases such as methanol during the entire slag discharge process, eliminating the need for manual disassembly and cleaning of the filter. This completely eliminates the safety and environmental hazards associated with traditional bag or sintered rod filters, such as easy failure, high manual cleaning risks, and harsh production environments.

[0016] 4. The countercurrent pulse backwash tank is equipped with a level gauge with remote signal transmission function, and is linked with the air inlet control valve, liquid discharge control valve and backwash control valve. It can automatically control the pulse backwash time according to the liquid level in the tank. Attached Figure Description

[0017] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of a filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to this utility model. Figure 2 for Figure 1 A magnified front view of the non-disassembly and cleaning ammonium chloride removal filter in the middle; Figure 3 for Figure 1 A magnified lateral view of the ammonium chloride removal filter that does not require disassembly and cleaning. Figure 4 for Figure 1 A magnified top view of the ammonium chloride removal filter that does not require disassembly and cleaning. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0020] Example 1: A filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride, such as... Figure 1 ~ Figure 4 As shown, the system includes a non-disassembly and cleaning ammonium chloride filter (hereinafter referred to as the filter), and a filter backwashing passage, a methanol passage, and a butamidine-methanol hydrochloride passage connected to the filter. The filter backwashing passage includes a counter-current pulse backwash tank 43, a drain control valve 46, a flow meter 47, and a butamidine-methanol hydrochloride clear liquid storage tank 48, all connected in sequence to the filter. The butamidine-methanol hydrochloride passage includes a butamidine-methanol hydrochloride solution transfer pump 50 and a butamidine-methanol hydrochloride solution storage tank 49, all connected in sequence to the filter. The methanol passage includes a methanol transfer pump 52 and a methanol storage tank 51, all connected in sequence to the filter.

[0021] The filter is a sealed container, consisting of an upper filter head 2, a filter body 1, and a lower filter head 3 from top to bottom. The upper filter head 2, filter body 1, and lower filter head 3 are all made of 2205 duplex stainless steel and are connected sequentially to form a sealed container.

[0022] The filter body 1 is a cylindrical shape with openings at the top and bottom, and a filter mounting lug 13 is fixedly welded to the middle of its side wall. A transverse support arm 141 is welded to the outside of the side wall of the filter body 1. One end of the transverse support arm 141 is welded and fixed to the filter body 1, and the filter top end cap 2 is connected to the other end of the transverse support arm 141 through an L-shaped support member 14.

[0023] The L-shaped support member 14 includes a vertical support section and a horizontal bending section. The other end of the horizontal support arm 141 is pivotally connected to the lower end of the vertical support section of the L-shaped support member 14 via a pivot shaft, allowing the L-shaped support member 14 to rotate around the pivot shaft. A transmission screw 22 is vertically fixed at the top center of the filter upper end cap 2. The upper part of the transmission screw 22 passes through the end of the horizontal bending section of the L-shaped support member 14 and is threadedly connected to the disc-shaped opening and closing handwheel 15. The opening and closing handwheel 15 is rotatably connected to the L-shaped support member 14 and axially limited. Specifically, for example, a connecting bushing is integrally formed at the bottom of the opening and closing handwheel 15. This connecting bushing passes through the mounting hole at the end of the horizontal bending section of the L-shaped support member 14 and achieves axial fixation and rotational engagement with the L-shaped support member 14 through a thrust bearing and a shaft elastic retaining ring (or lock nut). The transmission screw 22 is driven to rise and fall by rotating the opening and closing handwheel 15. The L-shaped support 14 provides a reaction force fulcrum, which drives the filter upper end cap 2 to rise or fall in the vertical direction. After being raised, the L-shaped support 14 can be pushed horizontally to rotate around the pivot axis to realize the translational opening and closing of the filter upper end cap 2.

[0024] A sintered metal filter screen, comprising a first sintered metal filter screen 5 and a second sintered metal filter screen 4, is provided around the inner wall of the filter body 1. The second sintered metal filter screen 4 is spot-welded to the side wall within the filter body 1. The upper and lower ends of the second sintered metal filter screen 4 (near the first flange 6 and the second flange 8) are sealed and fixedly connected to the inner wall of the filter body 1. For example, the upper and lower ends of the second sintered metal filter screen are folded and then fully welded to the filter body 1 to achieve sealing and fixation, preventing ammonium chloride solids from passing through the gap between the second sintered metal filter screen 4 and the filter body 1, thus preventing filtration failure. A 5mm to 10mm annular gap is left between the second sintered metal filter screen 4 and the inner wall of the filter body 1. A second drain and backflushing port 36 is provided at the lower part of the side wall of the filter body 1, and the second drain and backflushing port 36 is connected to the annular gap between the second sintered metal filter screen 4 and the inner wall of the filter body 1.

[0025] The lower end cap 3 of the filter is a funnel-shaped structure with openings at both the top and bottom. Inside the lower end cap 3, a first sintered metal filter screen 5 is fixed to the side wall by spot welding. The upper and lower ends of the first sintered metal filter screen 5 (near the second flange 8 and the third flange 18) are fully welded to the inner wall of the lower end cap 3 to achieve sealing and fixation, preventing ammonium chloride solids from passing through the gap between the first sintered metal filter screen 5 and the lower end cap 3 and causing filtration failure. A 5mm to 10mm annular gap is also left between the first sintered metal filter screen 5 and the inner wall of the lower end cap 3. A first drain and backflushing port 37 is opened at the lower part of the side wall of the lower end cap 3, and the first drain and backflushing port 37 is connected to the annular gap between the first sintered metal filter screen 5 and the lower end cap 3. The annular gap is used to create a fully enclosed clear liquid collection channel. During countercurrent backwashing, this annular gap allows the high-pressure backwash liquid to be applied evenly to the entire surface of the sintered mesh, forming a scouring pressure field from the outside in without dead angles, which significantly improves the peeling efficiency of the material trapped on the filter screen surface.

[0026] The second metal sintered filter screen 4 and the first metal sintered filter screen 5 are made of 2205 duplex steel.

[0027] The filter upper end cap 2 is connected to the top of the filter body 1 via a first flange 6, and the bottom of the filter body 1 is connected to the filter lower end cap 3 via a second flange 8. The bottom opening of the filter lower end cap 3 is a slag discharge port 38, and a slag discharge valve 16 is provided below the slag discharge port 38. The slag discharge port 38 and the slag discharge valve 16 are connected via a third flange 18.

[0028] The first flange 6, the second flange 8, and the third flange 18 can all adopt conventional flange connection structures in the field, such as upper and lower flange structures. An O-ring silicone seal is set between the two mating flange faces and bolted to form a detachable sealed connection between the upper end cap 2 of the filter and the filter body 1, the filter body 1 and the lower end cap 3 of the filter, and the lower end cap 3 and the slag discharge valve 16.

[0029] The filter head 2 is a round cap with a series of interfaces, including: a sprayer installation port (with a spray valve 31 installed), a nitrogen inlet port (with a nitrogen valve 32 installed), a feed inlet (with a feed valve 33 installed), a pressure gauge installation port (with a first pressure gauge 34 installed), and a safety valve installation port (with a safety valve 35 installed). The first pressure gauge 34 is used to monitor the pressure in the filter, and the safety valve 35 is used to prevent the pressure in the filter from exceeding the preset pressure. A sprayer 21 is fixedly installed inside the filter head 2. The liquid inlet pipe of the sprayer 21 is connected to the methanol storage tank 51 through the spray valve 31 and the methanol transfer pump 52. Methanol in the methanol storage tank 51 is used to clean the solid filter residue inside the filter online through the methanol transfer pump 52. The methanol is atomized and sprayed by the sprayer 21, which can quickly wash and slurry the retained solid ammonium chloride online, making it into a slurry with excellent fluidity. The feed valve 33 is connected to the butamidine hydrochloride methanol solution storage tank 49 via the butamidine hydrochloride methanol solution transfer pump 50, so as to introduce butamidine hydrochloride methanol solution into the filter body 1.

[0030] A nitrogen purging tube 12 is installed inside the filter. The upper end of the nitrogen purging tube 12 is detachably connected to the outlet of the nitrogen valve 32. For example, the upper end of the nitrogen purging tube 12 is inserted into the outlet of the nitrogen valve 32, and the two are sealed and fixed by a rubber ring. After the filter upper end cap 2 is raised, the nitrogen purging tube 12 can be pulled out and removed to facilitate the outward movement of the filter upper end cap 2. The nitrogen purging tube 12 is connected to an external nitrogen generator or nitrogen source through the nitrogen valve 32 and the air inlet pipe to introduce nitrogen into the bottom of the filter. The upper part of the nitrogen purging tube 12 is vertical, and the lower part is bent along the inner wall of the filter lower end cap 3, with the lower end opening facing the slag discharge port 38. The slag discharge valve 16 is connected to the upper feed port of the external ammonolysis reactor (or ammonolysis reaction liquid storage tank) through a pipe to form a fully closed loop.

[0031] The first drain and backwash port 37 and the second drain and backwash port 36 serve as both discharge ports for the filtered clear liquid and backwash ports for the second sintered metal filter screen 4 and the first sintered metal filter screen 5, enabling online backwashing, improving filtration performance, and extending the filtration cycle. The specific pathways for draining and backwashing are as follows: The countercurrent pulse backwash tank 43 has an upper drain port 40 at the top, an air inlet (with an air inlet control valve 42 installed on it) and a pressure gauge mounting port (with a second pressure gauge 44 installed on it) at the top, and a liquid inlet (with a backwash control valve 39 installed on it) at the bottom. A level gauge 45 is installed on the tank body. The level gauge 45 can be a conventional level detection device in the art, such as a magnetic float level gauge with signal remote transmission function, used to monitor the liquid level in the countercurrent pulse backwash tank 43. The second drain and backwash port 36 and the first drain and backwash port 37 are connected to a tee through pipelines, and then merged into one line, which is connected to the inner cavity of the countercurrent pulse backwash tank 43 through the backwash control valve 39. The upper drain port 40 is connected to the drain control valve 46, the flow meter 47, and the butamidine methanol hydrochloride clear liquid storage tank 48 in sequence through pipelines. The intake pipe of the intake control valve 42 is connected to an external nitrogen generator or nitrogen source. Nitrogen is connected to the inner cavity of the backwash tank 43 through the intake control valve 42. The intake control valve 42, the drain control valve 46, and the backwash control valve 39 are all automatic control valves, which can be solenoid valves, pneumatic valves, or electric valves. For example, in a preferred embodiment, the control terminals of the intake control valve 42, the drain control valve 46, and the backwash control valve 39 are all connected to the output terminal of a programmable logic controller (PLC). The input terminal of the PLC is connected to the signal output terminal of the level gauge 45. The valves automatically open and close according to the level signal fed back by the level gauge 45 to achieve automatic level interlock control.

[0032] The operation process of removing ammonium chloride without disassembly and washing according to this utility model is as follows: 1. Forward filtration and clear liquid collection: Used for solid-liquid separation of butamidine hydrochloride methanol solution, intercepting solid ammonium chloride, and collecting clear filtrate.

[0033] Close the slag discharge valve 16, the air inlet control valve 42, the nitrogen valve 32, and the spray valve 31; open the backwash control valve 39, the liquid discharge control valve 46, and the feed valve 33; start the butamidine hydrochloride methanol solution transfer pump 50.

[0034] The concentrated butamidine hydrochloride-methanol solution enters the filter through the feed valve 33. Under pressure, the solid ammonium chloride byproduct is trapped inside the second metal sintered filter screen 4 and the first metal sintered filter screen 5. The filtered butamidine hydrochloride-methanol solution passes through the second metal sintered filter screen 4 and the first metal sintered filter screen 5, collects in the annular gap behind the screen, and flows out through the first drain and backflushing port 37 and the second drain and backflushing port 36. It then enters the countercurrent pulse backflushing tank 43 through the backflushing control valve 39. When the liquid level of the butamidine hydrochloride-methanol solution is higher than the upper drain port 40, it overflows from the upper drain port 40, passes through the flow meter 47 and the drain control valve 46, and is finally collected in the butamidine hydrochloride-methanol solution storage tank 48. Meanwhile, the countercurrent pulse backwash tank 43 always retains a full level of butamidine methanol hydrochloride solution (liquid level up to the upper drain port 40).

[0035] 2. Backwashing stage with countercurrent pulses: After a period of production and use, when solid ammonium chloride accumulates on the surfaces of the second metal sintered filter screen 4 and the first metal sintered filter screen 5, causing the flow meter 47 to display a clear liquid flow rate lower than the set threshold, the butamidine hydrochloride methanol solution delivery pump 50 is turned off.

[0036] Close the feed valve 33, backwash control valve 39, and drain control valve 46.

[0037] Open the air intake control valve 42 to introduce compressed nitrogen into the countercurrent pulse backwash tank 43 to increase the pressure. When the second pressure gauge 44 detects that the pressure inside the tank reaches 0.65 MPa, quickly open the backwash control valve 39 to perform pulse backwashing. The clarified filtrate stored in the countercurrent pulse backwash tank 43, driven by high-pressure nitrogen, is flushed in the reverse direction along the first drain and backwash port 37 and the second drain and backwash port 36 into the annular gap between the second metal sintered filter screen 4, the first metal sintered filter screen 5 and the inner wall of the filter, forming a strong pulse pressure from the outside to the inside, peeling off the solid ammonium chloride adhering to the second metal sintered filter screen 4 and the first metal sintered filter screen 5, and quickly restoring the filter screen throughput. When the liquid level gauge 45 reaches the set value, the air intake control valve 42 and the backwash control valve 39 are closed through the control signal to stop backwashing, thereby realizing the control of the backwashing time through the signal output of the liquid level gauge 45.

[0038] After backwashing is complete, return to step 1 for forward filtration and clear liquid collection.

[0039] 3. Stages of filter pressing, pulping, and slag removal without disassembly and washing: When excessive ammonium chloride solids accumulate in the filter and the backwashing in step 2 cannot restore the flow rate, online slag removal is performed: (1) Nitrogen desiccation: Close the slag discharge valve 16 and the feed valve 33. Open the nitrogen valve 32, the liquid discharge control valve 46 and the backwash control valve 39. Introduce 0.65MPa high-pressure nitrogen into the filter through the nitrogen insertion pipe 12. Directional jetting directly blows up the residual butamidine hydrochloride methanol solution precipitated at the bottom of the filter lower end cap 3. Under the action of high-pressure nitrogen, after passing through the second metal sintered filter screen 4 and the first metal sintered filter screen 5, the butamidine hydrochloride methanol clear liquid enters the butamidine hydrochloride methanol clear liquid storage tank 48 for recovery after passing through the first liquid discharge and backwash port 37, the second liquid discharge and backwash port 36, the backwash control valve 39, the countercurrent pulse backwash tank 43, and the liquid discharge control valve 46. When the flow meter 47 shows no liquid outflow, close the nitrogen valve 32 to complete the nitrogen desiccation.

[0040] (2) Spraying and slurrying: Close the slag discharge valve 16, feed valve 33, backwash control valve 39, and liquid discharge control valve 46; open the spray valve 31 and start the methanol delivery pump 52 to atomize and spray the methanol in the methanol storage tank 51 onto the surface of the solid ammonium chloride inside the filter through the sprayer 21; then open the nitrogen valve 32 to spray nitrogen gas at a pressure of 0.65 MPa from the bottom of the filter lower head 3 through the filter press purging nitrogen insertion pipe 12 to perform bottom blowing pneumatic bubbling and stirring of the solid ammonium chloride and methanol liquid inside the filter, quickly dispersing the solid ammonium chloride and mixing it evenly with the methanol to form a free-flowing ammonium chloride-methanol slurry. After slurrying is completed, close the spray valve 31, the nitrogen valve 32, and stop the methanol delivery pump 52.

[0041] (3) Closed-loop slag discharge: Open the slag discharge valve 16 and reopen the nitrogen valve 32. At the same time, the feed valve 33, spray valve 31, and backwash control valve 39 are closed. Under the assistance of internal nitrogen positive pressure, the ammonium chloride methanol slurry is directly pressed into the ammonium hydrolysis reactor through the slag discharge port 38 and pipeline. After being combined with the ammonium hydrolysis reaction liquid, it is sent to the "three-in-one" equipment for large-scale filtration and drying of ammonium chloride. There is no methanol gas leakage during the entire slag discharge process, and there is no need to disassemble the filter. Thus, the filtration of ammonium chloride is achieved.

[0042] Finally, it should be noted that the above examples are merely a few specific embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride, characterized in that: The filter includes a filter and a counter-current pulse backwash tank (43). The filter includes a filter upper end cap (2), a filter body (1), and a filter lower end cap (3) that are detachably connected from top to bottom. A sintered metal filter screen is provided around the inner wall of the filter. The sintered metal filter screen is fixedly connected to the inner wall of the filter and leaves an annular gap. A filter press purging nitrogen insertion pipe (12) is provided inside the filter. The bottom opening of the filter lower end cap (3) is a slag discharge port (38). The lower end outlet of the filter press purging nitrogen insertion pipe (12) is directly opposite the slag discharge port (38). The upper part of the countercurrent pulse backwash tank (43) is provided with an upper drain port (40), an air inlet control valve (42) is installed at the top, a backwash control valve (39) is installed at the bottom, and a level gauge (45) is installed on the tank body; the filter is connected to the backwash control valve (39), and the upper drain port (40) is connected to the butamidine methanol clear liquid storage tank (48) through the flow meter (47) and the drain control valve (46); the level gauge (45) is connected to the air inlet control valve (42), the drain control valve (46) and the backwash control valve (39) for signal connection to realize the level interlock control.

2. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 1, characterized in that: The filter body (1) has a second drain and backflush port (36) on the lower side wall. The filter lower end cap (3) is funnel-shaped, and the lower part of the side wall is provided with a first drain and backflush port (37). The sintered metal filter screen includes a second sintered metal filter screen (4) surrounding the inner wall of the filter body (1) and a first sintered metal filter screen (5) surrounding the inner wall of the filter lower end cap (3); one end of the first drain and backflushing port (37) is connected to the annular gap between the first sintered metal filter screen (5) and the filter lower end cap (3), and one end of the second drain and backflushing port (36) is connected to the annular gap between the second sintered metal filter screen (4) and the filter body (1); the other end of the first drain and backflushing port (37) and the second drain and backflushing port (36) are connected to the backflushing control valve (39) through a tee.

3. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 2, characterized in that: The filter upper end cap (2) is connected to the filter body (1) through the first flange (6), the filter body (1) is connected to the filter lower end cap (3) through the second flange (8), and a slag discharge valve (16) is provided below the slag discharge port (38). The slag discharge port (38) and the slag discharge valve (16) are connected through the third flange (18).

4. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 3, characterized in that: The filter head (2) is equipped with a spray valve (31), a nitrogen valve (32), a feed valve (33), a first pressure gauge (34), and a safety valve (35); a sprayer (21) is provided inside the filter head (2), the sprayer (21) is fixedly connected to the filter head (2), and after passing through the spray valve (31), it is connected to the methanol storage tank (51) through the methanol transfer pump (52).

5. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 4, characterized in that: Nitrogen gas is connected to the inner cavity of the counter-current pulse backwash tank (43) through the inlet control valve (42) and to the inner cavity of the filter through the nitrogen valve (32); The butamidine hydrochloride methanol solution storage tank (49) is connected to the filter cavity through the butamidine hydrochloride methanol solution transfer pump (50) and the feed valve (33).

6. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 5, characterized in that: The gap between the second metal sintered filter screen (4) and the inner wall of the filter body (1) is 5-10 mm; The gap between the first metal sintered filter screen (5) and the inner wall of the filter lower end cap (3) is 5-10 mm.

7. The filtration system for removing ammonium chloride without disassembly and washing during the synthesis of butamidine hydrochloride according to claim 6, characterized in that: The filter upper end cap (2) is provided with a transmission screw (22) at the top center. The lower end of the transmission screw (22) is fixedly connected to the filter upper end cap (2), and the upper part passes through the end of the horizontal bend section of the L-shaped support (14) and is threadedly connected to the opening and closing handwheel (15). At the same time, the opening and closing handwheel (15) is rotatably connected to the L-shaped support (14) and is axially limited. The filter body (1) is fixedly connected to a transverse support arm (141) on the side wall, and the vertical support section of the L-shaped support member (14) is pivotally connected to the transverse support arm (141) via a rotating shaft.

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