Maleic anhydride production system with low solvent consumption

Abstract

The invention relates to the technical field of maleic anhydride production, in particular to a maleic anhydride production system with low solvent consumption. Comprising a maleic anhydride reactor, the maleic anhydride reactor is connected with a switching cooler through a first gas cooler, the switching cooler is sequentially connected with an absorption tower, a desorption tower, a light component tower and a finished product tower, and a solid phosphorus intercepting device is arranged at the bottom in the switching cooler. Phosphorus is intercepted at the position of the switching cooler, the motion route of reaction gas is limited through the side baffles and the upper baffle, gas resistance is adjusted through the forming positions of side baffle punched holes and the forming density of different heights, the top side baffle is not provided with punched holes, and the bottom side baffle is not provided with side baffles. The Pall ring packing on the upper, middle and lower layers can be fully utilized. The pressure drop required by the device is as small as possible, every 10-20 stainless steel Pall rings with the diameter of 5-15 mm are adopted as a group and are connected in series through a stainless steel rope, and high-speed reaction gas is prevented from being blown to an absorption tower.

Description

Technical Field

[0001] The invention relates to the technical field of maleic anhydride production, and in particular to a maleic anhydride production system with low solvent consumption. Background Art

[0002] The main process synthesis routes of maleic anhydride are benzene oxidation and n-butane oxidation. Before 2015, maleic anhydride produced by benzene oxidation was the mainstream in my country. After 2015, the production route using n-butane as raw material gradually increased due to its low raw material cost and environmental advantages. After 2020, the benzene oxidation method was basically eliminated. The n-butane method for producing maleic anhydride uses n-butane as raw material, and catalytic oxidation is used in a tubular reactor under the action of vanadium phosphorus oxygen catalyst to prepare maleic anhydride in the gas phase n-butane state. The reaction gas containing maleic anhydride produced in the reactor enters the downstream post-processing unit, which includes a series of distillation towers and solvent washing and regeneration equipment such as absorption, analysis, and product refining. In the post-processing unit, an organic solvent with high boiling point, low viscosity, good chemical stability, and weak affinity with water is generally used to absorb the maleic anhydride in the reaction gas, and then sent to the desorption tower for decompression and separation, and then distilled to obtain refined anhydride. The commonly used solvents at present are diisobutyl hexahydrophthalate (DIBE) and dibutyl phthalate (DBP), and the proportion of maleic anhydride units using DBP solvent process exceeds 70%.

[0003] The core of maleic anhydride production process is the reaction process. Its main principle is that the raw material n-butane and air are fully mixed in a certain proportion and then enter the reactor. High-temperature heat release and gas-solid phase oxidation reaction occur in the tube array filled with a certain amount of catalyst with VPO as the main component to generate maleic anhydride.

[0004] When n-butane passes through the reactor, about 80-88% of n-butane participates in the reaction, and the side reactions mainly convert into CO, CO2 and H2O. In addition to CO, CO2 and H2O, a small amount of acetic acid, acrylic acid, tar and other substances are also generated in the reactor.

[0005] The air at normal temperature and pressure is compressed by the blower unit and then heated to 160°C by the air heater. The n-butane in the n-butane buffer tank is heated to 125-135°C. The superheated n-butane gas is mixed with air through a mixer and enters the tube-type fixed bed reactor; the reaction gas enters the tube side and undergoes oxidation reaction under the action of the catalyst, and the co-catalyst trimethyl phosphate (TMP) is added during the reaction. The reaction product gas after the reaction is cooled to 130-160°C by a gas cooler and a switching cooler and then sent to the post-processing unit. The post-processing unit uses solvents such as DBP to absorb, extract and separate the maleic anhydride product.

[0006] The n-butane oxidation reaction itself will generate a large amount of water. Since maleic anhydride is easily soluble in DBP, while DBP is insoluble in water, maleic anhydride is absorbed by DBP solvent in the absorption tower, and most of the water carried is stripped out in the absorption tower. However, when DBP solvent is in a water environment and there is an acidic substance as a catalyst, DBP will decompose into phthalic anhydride and n-butanol, and the strong acid phthalic acid produced by the reaction of phthalic anhydride and water further promotes the decomposition of DBP. Therefore, it is very important to eliminate the acidic substances in the absorption tower from the source.

[0007] The catalyst used in the production of maleic anhydride by oxidation of n-butane is a vanadium phosphorus oxygen catalyst. The phosphorus in the catalyst is very easy to be lost at a reaction operating temperature of about 420°C for a long time. Therefore, the current maleic anhydride devices are all adding trimethyl phosphate to the reaction system as a means of supplementing phosphorus. A set of 50,000 tons / year maleic anhydride devices add about 24 tons of trimethyl phosphate each year. After the phosphorus element falls off the vanadium phosphorus oxygen catalyst, it reacts with the oxygen in the reaction gas at 420°C to generate phosphorus pentoxide. The reaction gas is cooled from the reactor to 265°C through the first gas cooler. During this cooling process, the phosphorus pentoxide in the reaction gas reacts with water to generate metaphosphoric acid. The reaction gas continues to be cooled to 155°C through the switching cooler. During this cooling process, the metaphosphoric acid reacts with water to generate pyrophosphoric acid. The reaction gas carries pyrophosphoric acid into the absorption tower and is cooled to less than 100°C. The pyrophosphoric acid reacts with water to generate phosphoric acid, which is a medium-strong acid. In the water environment, with phosphoric acid as the catalyst, the rate at which the DBP solvent in the absorption tower decomposes into phthalic anhydride and n-butanol increases greatly, ultimately causing an increase in DBP consumption. In severe cases, the presence of a large amount of phthalic anhydride in the DBP solvent causes the solvent water washing centrifuge to operate abnormally, ultimately leading to unplanned shutdowns.

[0008] Therefore, how to prevent the phosphorus element lost from the catalyst at high temperature from entering the absorption tower from the reaction system is the key to reducing DBP solvent consumption. Summary of the invention

[0009] The present invention provides a maleic anhydride production system with low solvent consumption in order to solve the problem of excessive solvent consumption caused by loss of phosphorus element in the catalyst.

[0010] In order to solve the above problems, the technical solution of the present invention is:

[0011] The low solvent consumption maleic anhydride production system of the present invention comprises a maleic anhydride reactor, which is connected to a switching cooler via a first gas cooler, and the switching cooler is sequentially connected to an absorption tower, a decomposition tower, a light component tower, and a finished product tower, wherein a solid phosphorus interception device is arranged at the bottom of the switching cooler.

[0012] Phosphoric acid has a melting point of 42.3°C and a freezing point of 21.1°C. It becomes anhydrous at 150°C, becomes pyrophosphoric acid when heated to 215°C, and becomes metaphosphoric acid when heated to 300°C. It will be converted into gaseous phosphorus pentoxide when it exceeds 340°C. Therefore, within 340°C, phosphorus exists in solid or liquid form. At the same time, since the pressure after the reactor is about 195KPa, the saturation temperature of water is 120°C at this time, and water above this temperature is in a gaseous overheated state. Therefore, the temperature range in which phosphorus in the reaction gas is solid and other substances are gaseous or liquid is required to be 150°C-340°C. The inlet of the switching cooler is 260°C and the outlet is 158°C, so removing phosphorus in the switching cooler is the best choice.

[0013] Furthermore, the solid phosphorus interception device includes a side baffle, which is vertically arranged in a three-sided surrounding shape corresponding to the reaction gas outlet direction of the switching cooler. The top of the side baffle is obliquely connected to the upper baffle, and the upper baffle is inclined to close the space above the reaction gas outlet. Ball ring fillers are stacked on the side of the side baffle away from the reaction gas outlet.

[0014] The function of the upper baffle is to prevent the reaction gas from directly passing over the ball ring packing and overflowing from the reaction gas outlet.

[0015] Furthermore, the ball ring fillers are stainless steel ball rings with a diameter of 5-15 mm, and 10-20 of them are packed in series with stainless steel ropes in a group, and the height of the ball ring fillers submerges the upper edge of the side baffle.

[0016] Considering that the device requires the pressure drop to be as small as possible, stainless steel ball rings with a diameter of 5-15mm are used. In order to prevent them from being blown to the absorption tower by high-speed reaction gas, every 10-20 ball rings are connected in series with stainless steel ropes. The use of ball rings of this size can ensure the interception of solid pyrophosphoric acid while keeping the pressure drop acceptable.

[0017] Furthermore, the bottom of the side baffle is fixed by the inner walls on both sides of the switching cooler, and the bottom does not contact the bottom of the switching cooler.

[0018] Furthermore, punching holes are provided in the middle and lower parts of the side baffle, and the punching area is smaller than the size of the ball ring.

[0019] A punched baffle is welded to the lower head of the switching cooler outlet. The opening in the lower middle part of the baffle allows the reaction gas flow to pass through. The area of ​​the triangular hole of the opening should be smaller than the size of the ball ring to prevent the ball ring from being blown away through the opening.

[0020] Furthermore, the density of the punching holes increases from top to bottom.

[0021] Preferably, the punching hole is an equilateral triangle.

[0022] As the reaction gas moves from top to bottom, the packing layer becomes thicker and thicker, and the resistance gradually increases. In order to make the packings in the upper, middle and lower layers all play the filtering and capturing functions, the resistance of the middle packing layer is adjusted by adjusting the opening density. The upper side baffle is not perforated to artificially increase the resistance, and there is no side baffle at the bottom. The layer-by-layer adjustment greatly improves the filtering effect of the ball ring packing.

[0023] Working principle:

[0024] Normal butane and air enter the maleic anhydride reactor and react to generate maleic anhydride under the action of vanadium phosphorus oxygen catalyst. A co-catalyst trimethyl phosphate is added during the reaction. The reaction gas generated after the reaction is initially cooled in the first gas cooler and then enters the switching cooler for cooling through the reaction gas inlet. The reaction gas enters the bottom of the switching cooler and, under the blocking action of the upper baffle, passes through the ball ring packing area surrounded by three side baffles to filter and intercept the solid pyrophosphoric acid in the reaction gas from top to bottom. The reaction gas moves to the reaction gas outlet through the punching holes of the side baffles and the gap at the bottom, exits the switching cooler through the reaction gas outlet, and then passes through the absorption tower, the analysis tower, the light component tower, and the finished product tower in sequence to become maleic anhydride finished product.

[0025] The beneficial effects of the present invention are as follows:

[0026] (1) The present invention selects to intercept phosphorus element at the switching cooler position, and limits the movement route of the reaction gas by setting the side baffles and the upper baffles. The resistance to the movement of the reaction gas is adjusted by the opening position of the punching holes of the side baffles and the opening density at different heights. The top side baffle is not punched, and the bottom side baffle is not provided, so as to adjust the movement resistance of the reaction gas, so that the ball ring fillers of the upper, middle and lower layers can be fully utilized, thereby improving the filtration efficiency.

[0027] (2) The present invention takes into account the requirement for the pressure drop to be as small as possible and adopts a stainless steel ball ring with a diameter of 5-15 mm. To prevent the ball ring from being blown to the absorption tower by the high-speed reaction gas, each group of 10-20 ball rings is connected in series with a stainless steel rope. The use of ball rings of this size can ensure the interception of solid pyrophosphoric acid while keeping the pressure drop acceptable.

[0028] (3) The present invention welds a punched baffle plate at the lower head of the switch cooler outlet. The lower opening in the baffle plate allows the reaction gas flow to pass through. The area of ​​the triangular hole of the opening is smaller than the size of the ball ring to prevent the ball ring from being blown away through the opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1It is a structural schematic diagram of the maleic anhydride production system with low solvent consumption of the present invention;

[0031] Figure 2 A side view of a switching cooler of the present invention;

[0032] Figure 3 A top view of the bottom of the cooler is switched for the present invention;

[0033] Figure 4 It is a structural schematic diagram of the upper baffle of the present invention;

[0034] Figure 5 It is a structural schematic diagram of the side baffle of the present invention;

[0035] In the figure: 1, maleic anhydride reactor; 2, first gas cooler; 3, switching cooler; 4, absorption tower; 5, analysis tower; 6, light component tower; 7, finished product tower; 8, upper baffle; 9, side baffle; 901, punching; 10, reaction gas inlet; 11, reaction gas outlet; 12, ball ring packing. DETAILED DESCRIPTION

[0036] The present invention is explained in an understandable manner in conjunction with the embodiments below. The various embodiments in this specification are described in a progressive manner, and the same and similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0037] In one embodiment, Figure 1-5 As shown, a maleic anhydride production system with low solvent consumption includes a maleic anhydride reactor 1, which is connected to a switching cooler 3 through a first gas cooler 2, and the switching cooler 3 is sequentially connected to an absorption tower 4, a desorption tower 5, a light component tower 6, and a finished product tower 7, and a solid phosphorus interception device is arranged at the bottom of the switching cooler 3. Three switching coolers 3 are arranged in parallel, and can be switched for use when the filler needs to be replaced and cleaned.

[0038] Phosphoric acid has a melting point of 42.3°C and a freezing point of 21.1°C. It becomes anhydrous at 150°C, becomes pyrophosphoric acid when heated to 215°C, and becomes metaphosphoric acid when heated to 300°C. If it exceeds 340°C, it will be converted into gaseous phosphorus pentoxide. Therefore, within 340°C, phosphorus exists in solid or liquid form. At the same time, since the pressure after the reactor is about 195KPa, the saturation temperature of water is 120°C at this time, and water above this temperature is in a gaseous overheated state. Therefore, the temperature range in which phosphorus in the reaction gas is solid and other substances are gaseous or liquid is required to be 150°C-340°C. The inlet of the switching cooler 3 is 260°C and the outlet is 158°C, so removing phosphorus in the switching cooler 3 is the best choice.

[0039] It can be understood that the solid phosphorus interception device includes a side baffle 9, which is vertically arranged in a three-sided surrounding shape corresponding to the direction of the reaction gas outlet 11 of the switching cooler 3. The top of the side baffle 9 is obliquely connected to the upper baffle 8, and the upper baffle 8 is inclined to close the space above the reaction gas outlet 11. Ball ring fillers 12 are stacked on the side of the side baffle 9 away from the reaction gas outlet 11.

[0040] The function of the upper baffle 8 is to prevent the reaction gas from directly passing over the ball ring packing 12 and directly overflowing from the reaction gas outlet 11 .

[0041] It can be understood that the ball ring packing 12 is a stainless steel ball ring with a diameter of 5-15 mm, and each group of 10-20 is filled in series with stainless steel ropes, and the height of the ball ring packing 12 submerges the upper edge of the side baffle 9. Considering that the device requires the pressure drop to be as small as possible, a stainless steel ball ring with a diameter of 5-15 mm is used. In order to prevent the high-speed reaction gas from blowing to the absorption tower 4, each group of 10-20 ball rings is connected in series with stainless steel ropes. The use of ball rings of this size can ensure that the solid pyrophosphoric acid is intercepted while the pressure drop is acceptable.

[0042] It can be understood that the bottom of the side baffle 9 is fixed by the inner walls on both sides of the switching cooler 3, and the bottom does not contact the bottom of the switching cooler 3.

[0043] It can be understood that the middle and lower parts of the side baffle 9 are provided with punching holes 901, and the area of ​​the punching holes 901 is smaller than the size of the ball ring.

[0044] A baffle with punched holes 901 is welded at the lower head of the outlet of the switching cooler 3. The opening in the lower middle part of the baffle allows the reaction gas flow to pass through. The area of ​​the triangular hole of the opening should be smaller than the size of the ball ring to prevent the ball ring from being blown away through the opening.

[0045] It can be understood that the density of the punching holes 901 increases from top to bottom.

[0046] As the reaction gas moves from top to bottom, the packing layer becomes thicker and thicker, and the resistance gradually increases. In order to make the packings in the upper, middle and lower layers all play the filtering and capturing functions, the resistance of the middle packing layer is adjusted by adjusting the opening density. The upper side baffle 9 is not perforated to artificially increase the resistance. The side baffle 9 is not provided at the bottom. The filtering effect of the ball ring packing 12 is greatly improved by adjusting layer by layer.

[0047] Working principle:

[0048] The n-butane heated to 130±5°C and the air preheated to 160°C (the molar concentration of n-butane in the air is 1.6-2.1%, and the air velocity is 1700-2100 m / h) enter the maleic anhydride reactor 1, and react to generate maleic anhydride under the action of the vanadium phosphorus oxygen catalyst produced by Clariant. The co-catalyst trimethyl phosphate (1.0-3.0 ppm volume fraction) is added during the reaction. The reaction product gas after the reaction is initially cooled to 250°C by the first gas cooler 2, and then enters the switching cooler 3 through the reaction gas inlet 10 to be cooled to 135-160°C. The reaction gas enters the bottom of the switching cooler 3, and under the blocking effect of the upper baffle 8, passes through the ball ring packing 12 area surrounded by three side baffles 9, and solid pyrophosphorus in the reaction gas is removed from top to bottom. The acid is filtered and intercepted, and the reaction gas moves to the reaction gas outlet 11 through the punching hole 901 of the side baffle 9 and the gap at the bottom, and then enters the absorption tower 4. The top temperature of the absorption tower 4 is 70-78°C and the pressure is 20-30Kpa. The DBP solvent enters from the top of the absorption tower 4 and contacts with the reaction gas in countercurrent to absorb the maleic anhydride product in the reaction gas. The remaining air and by-products enter the RTO incineration system at the rear from the top of the tower; the maleic anhydride-rich solvent at the bottom of the absorption tower 4 enters the analysis tower 5. The analysis tower 5 adopts negative pressure operation, the pressure is controlled at -95KPa, and the bottom temperature of the analysis tower 5 is controlled at 185-198°C. Under this condition, the solvent and the maleic anhydride product are separated, the maleic anhydride product is extracted from the top of the tower, and the solvent is extracted from the bottom of the tower. The maleic anhydride product extracted from the top of the analytical tower 5 enters the light component tower 6. The light component tower 6 adopts negative pressure operation, and the pressure is controlled at about -85KPa. The temperature at the bottom of the tower is controlled at 140-150°C. Under this condition, the light component impurities in the maleic anhydride are removed from the bottom of the tower, and the crude maleic anhydride product is extracted from the bottom of the light component tower 6; the crude maleic anhydride extracted from the bottom of the light component tower 6 is transferred to the middle of the finished product tower 7. The pressure of the finished product tower 7 is controlled at about -89KPa, and the temperature at the bottom of the tower is controlled at 130-140°C. Under this condition, the light component impurities in the crude maleic anhydride are further removed from the bottom of the tower, and the heavy component impurities in the crude maleic anhydride are removed from the bottom of the tower. The product maleic anhydride is extracted from the middle of the finished product tower 7 to obtain the maleic anhydride product.

[0049] Specifically, n-butane heated to 130±5°C and air preheated to 160°C (the molar concentration of n-butane in air is 1.8% and the air velocity is 1900 m / h) enter maleic anhydride reactor 1, and react to generate maleic anhydride under the action of vanadium phosphorus oxygen catalyst produced by Clariant. Trimethyl phosphate (2.0 ppm volume fraction) is added as a co-catalyst during the reaction. The reaction product gas is initially cooled to 250°C by the first gas cooler 2, and then enters the switching cooler 3 through the reaction gas inlet 10 to be cooled to 147.5±12.5°C. The reaction gas enters the bottom of the switching cooler 3, and under the blocking action of the upper baffle 8, passes through the ball ring packing 12 area surrounded by three side baffles 9, and solid pyrophosphoric acid in the reaction gas is subjected to the treatment from top to bottom. After filtration and interception, the reaction gas moves to the reaction gas outlet 11 through the punching holes 901 of the side baffle 9 and the gap at the bottom, and then exits the switching cooler 3 through the reaction gas outlet 11, and then enters the absorption tower 4. The top temperature of the absorption tower 4 is 74±4°C, and the pressure is 25±5Kpa. The DBP solvent enters from the top of the absorption tower 4, contacts with the reaction gas in countercurrent, and absorbs the maleic anhydride product in the reaction gas. The remaining air and by-products enter the RTO incineration system at the rear from the top of the tower; the maleic anhydride-rich solvent at the bottom of the absorption tower 4 enters the analysis tower 5, and the analysis tower 5 adopts negative pressure operation, the pressure is controlled at -95KPa, and the bottom temperature of the analysis tower 5 is controlled at 191.5±6.5°C. Under this condition, the solvent and the maleic anhydride product are separated, the maleic anhydride product is extracted from the top of the tower, and the solvent is extracted from the bottom of the tower. The maleic anhydride product extracted from the top of the analysis tower 5 enters the light component tower 6. The light component tower 6 adopts negative pressure operation, and the pressure is controlled at about -85KPa. The temperature at the bottom of the tower is controlled at 145±5°C. Under this condition, the light component impurities in the maleic anhydride are removed from the bottom of the tower, and the crude maleic anhydride product is extracted from the bottom of the light component tower 6; the crude maleic anhydride extracted from the bottom of the light component tower 6 is transferred to the middle of the finished product tower 7. The pressure of the finished product tower 7 is controlled at about -89KPa, and the temperature at the bottom of the tower is controlled at 135±5°C. Under this condition, the light component impurities in the crude maleic anhydride are further removed from the bottom of the tower, and the heavy component impurities in the crude maleic anhydride are removed from the bottom of the tower. The product maleic anhydride is extracted from the middle of the finished product tower 7 to obtain the maleic anhydride product.

[0050] Example 1

[0051] Using the above low solvent consumption maleic anhydride production system:

[0052] The φ5 ball ring is used. The ball ring is loosely stacked and connected in series by steel wire ropes. 15 balls are grouped. The interception plate is a punched steel plate. The punched holes are isosceles triangles with a side length of 3 cm. The number of holes reaches the reaction product flow rate of 2m / s. After production and use, it was found that the upper ball ring intercepted more reaction by-products and catalyst powder. The upper ball ring was not damaged. The middle and lower ball rings also intercepted a small amount of tar and other by-products and the shape was intact. The system pressure drop slowly increased from 10kpa at the beginning to 50kpa and could not run. The entire continuous production time can last for 45 days. The rich solvent of the absorption and analysis system of the maleic anhydride unit was tested and analyzed. The system contained 0.2% phthalic anhydride, 0.04PPm phosphorus content, and 7kg / t DBP solvent consumption. This shows that this scheme has a good interception effect on the catalyst phosphorus element and by-product tar in the reaction system, greatly reducing the DBP solvent consumption, and can maintain a long period of production operation. The upper ball ring and the middle and lower ball ring structures were not broken, and the subsequent absorption and analysis solvent system did not find any broken metal fragments.

[0053] Comparative Example 1

[0054] The same as Example 1, except that φ3 ball rings are used, the ball rings are loosely stacked, the interception plate is a punched steel plate, the punching is φ2 circular, and the number of openings reaches the reaction product flow rate of 3m / s. After production use, it was found that the upper ball ring intercepted more reaction by-products and catalyst powders, and the upper ball ring was more broken, while the middle and lower ball rings were relatively clean and intact in shape. After running for 5 days, the system pressure drop rose from the initial 10kPa to 50kPa and could not run, and the equipment was forced to be opened for cleaning. The operation time of this solution is short, and it cannot guarantee continuous long-term production operation.

[0055] Comparative Example 2

[0056] The same as Example 1, the difference is that φ7 ball rings are used, the ball rings are loosely stacked, the interception plate is a punched steel plate, the punching is φ4 circular, and the number of openings reaches the reaction product flow rate of 1m / s. After production and use, it was found that the upper ball ring intercepted more reaction by-products and catalyst powder, the upper ball ring was more damaged, the middle and lower ball rings also intercepted a small amount of tar and other by-products and the shape was intact, the system pressure drop slowly rose from the initial 10kpa to 50kpa and could not run, and the entire continuous production time could last for 60 days. The rich solvent of the absorption and analysis system of the maleic anhydride device was analyzed and the system contained 0.4% phthalic anhydride, 0.07PPm phosphorus content, and 12kg / t DBP solvent consumption. Compared with the production state without adding interception measures, the solvent system contained 0.6% phthalic anhydride, 0.15PPm phosphorus content, and 18kg / t DBP solvent consumption. It shows that this scheme has a certain interception effect on the catalyst phosphorus element and by-product tar in the reaction system, and has a certain effect on reducing DBP solvent consumption. The upper ball ring was damaged to a certain extent, which might be caused by the upper air flow disturbance causing the ball rings to collide with each other. A small amount of broken metal fragments entered the subsequent absorption and analysis solvent system through the φ4 hole of the interception plate, causing the circulation pump inlet to be blocked.

[0057] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A maleic anhydride production system with low solvent consumption, characterized in that: The invention comprises a maleic anhydride reactor (1), wherein the maleic anhydride reactor (1) is connected to a switching cooler (3) via a first gas cooler (2), and the switching cooler (3) is sequentially connected to an absorption tower (4), a desorption tower (5), a light component tower (6), and a finished product tower (7), and a solid phosphorus interception device is arranged at the bottom of the switching cooler (3).

2. The low solvent consumption maleic anhydride production system according to claim 1, characterized in that: The solid phosphorus interception device comprises a side baffle (9), the side baffle (9) being vertically arranged in a three-sided surrounding shape corresponding to the direction of the reaction gas outlet (11) of the switching cooler (3), the top of the side baffle (9) being obliquely connected to the upper baffle (8), the upper baffle (8) being obliquely closed to the space above the reaction gas outlet (11), and a ball ring filler (12) being stacked on the side of the side baffle (9) away from the reaction gas outlet (11).

3. The low solvent consumption maleic anhydride production system according to claim 2, characterized in that: The ball ring fillers (12) are stainless steel ball rings with a diameter of 5-15 mm, and 10-20 of them are packed in series using stainless steel ropes.

4. The low solvent consumption maleic anhydride production system according to claim 3, characterized in that: The height of the ball ring packing (12) is such that it submerges the upper edge of the side baffle (9).

5. The low solvent consumption maleic anhydride production system according to claim 4, characterized in that: The bottom of the side baffle (9) is fixed by the inner walls on both sides of the switching cooler (3), and the bottom does not contact the inner bottom of the switching cooler (3).

6. The low solvent consumption maleic anhydride production system according to claim 2, characterized in that: The middle and lower parts of the side baffle (9) are provided with punching holes (901).

7. The low solvent consumption maleic anhydride production system according to claim 6, characterized in that: The punching hole (901) has an area smaller than the size of the ball ring.

8. The low solvent consumption maleic anhydride production system according to claim 7, characterized in that: The density of the punching holes (901) increases from top to bottom.

9. The low solvent consumption maleic anhydride production system according to claim 8, characterized in that: The punching hole (901) is an equilateral triangle.

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