A circulating spray system for ethylene glycol

Abstract

The present invention belongs to the technical field of polyester production equipment and discloses a circulating spray system for ethylene glycol. The system comprises a spray pipe, a scraper condenser, a downpipe, a liquid seal tank, a circulation pipe I, a circulation pipe II, a jacketed spray pipe, a conical cap distribution plate I, an external pipe I, and an external pipe II. The scraper condenser comprises a horizontal cylinder, a vertical cylinder, and a conical cap distribution plate II. The conical cap distribution plate II is located inside the vertical cylinder. The output end of the spray pipe is inserted into the vertical cylinder, with the orifice of the output end of the spray pipe facing the top of the conical cap distribution plate II. The conical cap distribution plate I is located above the conical cap distribution plate II. The jacketed spray pipe is sleeved on the spray pipe. One end of the circulation pipe I and the circulation pipe II are respectively connected to the liquid seal tank, and the other end is respectively connected to the input end of the spray pipe. The present invention can clean the spray pipe, the jacketed spray pipe, and the inner pipe of the circulation pipe between valves a and b and the spray pipe online to avoid blockage.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester production equipment and relates to a circulating spraying system for ethylene glycol. Background Art

[0002] During the polyester production process, the exhaust gas generated by the polycondensation reaction needs to be extracted through a vacuum system. However, this exhaust gas contains a large amount of entrained substances. As the temperature of the vacuum system decreases, some of these substances will precipitate and accumulate on the walls of the vacuum system pipes. This can easily cause blockage in the vacuum system pipes and is difficult to handle. In severe cases, it may even lead to forced shutdown. Therefore, before the exhaust gas enters the vacuum system, it usually passes through a scraper condenser to remove as much condensable gas and entrained substances as possible, and then allows the non-condensable gas to enter the vacuum system, thus solving the problem of vacuum system pipe blockage.

[0003] The specific method of removing condensable substances from the scraper condenser is to spray ethylene glycol, so that the ethylene glycol and the gaseous substances flow in an interlaced manner and absorb the condensable gas and capture the entrained substances. The used ethylene glycol is filtered and then circulated and sprayed through a circulation pump. However, among the captured substances, smaller substances are not easy to be removed, especially powder-like substances. These substances remain in the ethylene glycol, causing the ethylene glycol to gradually "become dirty" and increasing the possibility of blockage in the ethylene glycol circulation system pipeline.

[0004] In order to solve the above problems, the literature (Process Improvement of Vacuum System of Polyester Plant [J], Synthetic Fiber, 2009 (6): 46-48.) provides a circulating spray system of ethylene glycol, such as Figure 1 As shown, the ethylene glycol circulation spraying system includes a scraper condenser, a downpipe, a liquid seal tank 46, a buffer tank 47, a spray pipe 1, a circulation pipe I, a circulation pipe II, a circulation pipe III, a circulation pipe IV, a circulation pipe V, a feeding pipe, an overflow pipe, a production pipe I, a production pipe II, a switching pipe I, and a switching pipe II;

[0005] The scraper condenser includes a horizontal cylinder 45, a vertical cylinder 12, a connecting plate II 9, and a conical cap distribution plate II 6. The vertical cylinder 12 is fixedly connected to the upper part of the horizontal cylinder 45, and the two are connected; a gas phase port is provided at the upper part of the horizontal cylinder 45, and a discharge port is provided at the lower part of the horizontal cylinder 45; the conical cap distribution plate II is an umbrella-shaped structure, and a cone is provided on the top of the conical cap distribution plate II 6. The conical cap distribution plate II 6 is located inside the vertical cylinder 12, with the concave surface of the conical cap distribution plate II 6 facing downward, and the conical cap distribution plate II 6 is fixedly connected to the vertical cylinder 12 through the connecting plate II 9; a through hole I is provided on the circumferential surface of the vertical cylinder 12, and the output end of the spray pipe 1 is inserted into the interior of the vertical cylinder 12 through the through hole I, and the orifice of the output end of the spray pipe 1 is aligned with the cone; a vacuum suction port is provided on the top of the vertical cylinder 12, and the vacuum system is connected to the vacuum suction port;

[0006] The discharge port of the scraper condenser is connected to the liquid seal tank 46 through a downpipe; the liquid seal tank 46 is used to receive the circulating ethylene glycol and filter it;

[0007] One end of the circulation pipe 1 is connected to the bottom of the liquid seal tank 46, and the other end is connected to the input end of the spray pipe 1. Along the direction from the liquid seal tank 46 to the spray pipe 1, the circulation pipe 1 is sequentially provided with a valve s 41, a filter 1 38, a pump 1 36, a valve n 32, a plate heat exchanger 1 30, and a valve b 14. The pump 1 36 is used to transport the ethylene glycol in the liquid seal tank 46 to the spray pipe 1; the plate heat exchanger 1 30 is used to cool the ethylene glycol.

[0008] One end of circulation pipe II is connected to the bottom of liquid seal tank 46, and the other end is connected to the input end of spray pipe 1. Along the direction from liquid seal tank 46 to spray pipe I1, circulation pipe II is equipped with valve r 40, filter II 39, pump II 37, valve q 35, plate heat exchanger II 31, and valve a 13. Pump II 37 is used to transport ethylene glycol in liquid seal tank 46 to spray pipe 1; plate heat exchanger II 31 is used to cool the ethylene glycol.

[0009] Assume that there is a connection point A 52 on the circulation pipe I between pump I 36 and valve n 32, and a connection point B 53 on the circulation pipe I between valve n 32 and plate heat exchanger I 30; assume that there is a connection point C 54 on the circulation pipe II between pump II 37 and valve q 35, and a connection point D 55 on the circulation pipe II between valve q 35 and plate heat exchanger II 31; one end of switching pipe I is connected to connection point A 52, the other end of switching pipe I is connected to connection point D 55, and switching pipe I is provided with valve o 33; one end of switching pipe II is connected to connection point B 53, the other end of switching pipe I is connected to connection point C 54, and switching pipe II is provided with valve p 34;

[0010] Assume that there is a connection point E 56 on the circulation pipe I between the plate heat exchanger I 30 and the valve b 14, and a connection point F 57 between the plate heat exchanger II 31 and the valve a 13. One end of the production pipe I is connected to the connection point E 56, and the other end is connected to the outside world. Along the direction from the connection point E 56 to the outside world, the production pipe I is provided with valves k 27 and m 29 in sequence. The input end of the production pipe II is connected to the connection point F 57, and the output end of the production pipe II is connected to the production pipe I between valves k 27 and m 29. The production pipe II is provided with a valve l 28.

[0011] Assume that there is a connection point G 58 on the circulation pipe II between valve r 40 and filter II 39, and a connection point H 59 on the circulation pipe II between connection point F 57 and valve a13; one end of the circulation pipe III is connected to connection point G 58, and the other end is connected to connection point H 59; a jacketed heat exchanger 44 is provided on the circulation pipe III; jacketed heat exchanger 44 is used to heat ethylene glycol; a valve u 43 is provided on the circulation pipe III between jacketed heat exchanger 44 and connection point G 58, and a valve w 49 is provided on the circulation pipe III between jacketed heat exchanger 44 and connection point H 59;

[0012] Assume that a connection point I 60 is provided on circulation pipe I between valve s 41 and filter I 38, and a connection point J 61 is provided between connection point E 56 and valve b14; one end of circulation pipe IV is connected to connection point I 60, and the other end is connected to circulation pipe II between valve u 43 and jacketed heat exchanger 44; circulation pipe IV is provided with valve t 42; one end of circulation pipe V is connected to connection point J 61, and the other end is connected to circulation pipe III between valve w 49 and jacketed heat exchanger 44; circulation pipe V is provided with valve x 50;

[0013] Assume that there is a connection point K62 on the circulation pipe III between valve w49 and the jacketed heat exchanger 44, a connection point L63 on the production pipe I between valve k27 and valve m29, and a connection point M64 on the production pipe I between valve m29 and the discharge outlet of the production pipe I; one end of the feed pipe is connected to the connection point K62, and the other end of the feed pipe is connected to the connection point L63; the buffer tank 47 is set on the feed pipe; one end of the overflow pipe is connected to the buffer tank 47, and the other end is connected to the connection point M64 (the other end of the overflow pipe can also be directly connected to the outside world).

[0014] When there is too much ethylene glycol in the liquid seal tank 46 (ethylene glycol vapor in the tail gas is captured and falls into the circulation system), the total amount of ethylene glycol in the circulation system is kept stable by controlling the opening and closing of valves k 27, l 28, and m 29.

[0015] The spray pipe 1, scraper condenser, downpipe, liquid seal tank 46 and circulation pipe I form a glycol spray system; the spray pipe 1, scraper condenser, downpipe, liquid seal tank 46 and circulation pipe II form another glycol spray system; during normal use, only one glycol spray system is in use, and the other glycol spray system is on standby; in order to prevent accidents, in addition to using two sets of glycol spray systems, the switching pipe I and switching pipe II are also designed to prevent the problem of partial pipeline damage causing the inability to spray glycol.

[0016] When online cleaning of circulation pipe I is required, the valve is controlled so that circulation pipe I, circulation pipe IV, a part of circulation pipe III, and circulation pipe V form an online cleaning circulation system, thereby achieving cleaning of circulation pipe I, while circulation pipe II is still participating in ethylene glycol spraying; when online cleaning of circulation pipe II is required, the valve is controlled so that circulation pipe II and circulation pipe III form an online cleaning circulation system, thereby achieving cleaning of circulation pipe II, while circulation pipe I is still participating in ethylene glycol spraying; as described above, online cleaning of circulation pipes I and II can be achieved;

[0017] During the online cleaning process, ethylene glycol in the circulating pipe that is participating in the spraying can be introduced into the circulating pipe that is being cleaned online through the replenishing pipe, so that the circulating pipe that is being cleaned online can be further filled with ethylene glycol (when ethylene glycol overflows from the buffer tank 47 through the overflow pipe, it is filled).

[0018] However, the glycol circulation spraying system provided in this document has a fatal problem. Only circulation pipes I and II can be cleaned, while the inner pipe of spray pipe 1, the inner pipe of circulation pipe II between valve a 13 and the spray pipe, and the inner pipe of circulation pipe I between valve b 14 and the spray pipe cannot be cleaned. As a result, particles that cannot be filtered by the filter and some substances dissolved in ethylene glycol will slowly precipitate and adhere to the inner pipe of spray pipe I, reducing the pipe diameter and affecting the flow rate and spraying effect.

[0019] Therefore, it is of great significance to study a circulating spray system of ethylene glycol to solve the above problems. Summary of the Invention

[0020] The purpose of the present invention is to solve the problems existing in the prior art and provide a circulating spraying system for ethylene glycol.

[0021] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0022] A glycol circulation spray system includes a spray pipe, a scraper condenser, a downpipe, a liquid seal tank, a circulation pipe I, and a circulation pipe II. The scraper condenser includes a horizontal cylinder and a vertical cylinder. The output end of the spray pipe is inserted into the vertical cylinder. One end of the circulation pipe I and the circulation pipe II are respectively connected to the liquid seal tank, and the other end is respectively connected to the input end of the spray pipe. The circulation pipe I is provided with a valve s, a pump I, and a plate heat exchanger I. The circulation pipe II is provided with a valve r, a pump II, and a plate heat exchanger II. The valve s is located between the plate heat exchanger I and the liquid seal tank, and the valve r is located between the plate heat exchanger II and the liquid seal tank. The glycol circulation spray system also includes a jacketed spray pipe, an additional pipe I, and an additional pipe II.

[0023] The jacketed spray pipe is sleeved on the spray pipe; one end of the jacketed spray pipe is sealed and connected to the spray pipe, and the other end is inserted into the interior of the vertical cylinder;

[0024] Assume that there is a connection point N between the spray pipe and the plate heat exchanger I on the circulation pipe I; one end of the external pipe I is connected to the jacketed spray pipe, and the other end is connected to the connection point N; a valve b is provided on the circulation pipe I between the connection point N and the spray pipe;

[0025] Assume that there is a connection point O between the spray pipe and the plate heat exchanger II on the circulation pipe II; one end of the external pipe II is connected to the connection point O, and the other end is used to pass hot ethylene glycol above 120°C; a valve f is provided on the external pipe II.

[0026] When the interior of the spray pipe needs to be cleaned, valves are controlled to allow cold ethylene glycol (the plate heat exchanger can also cool the glycol) to continue spraying within the vertical cylinder through the jacketed spray pipe. Hot ethylene glycol, then above 120°C, is then allowed to pass through the spray pipe and spray within the vertical cylinder, effectively cleaning the interior of the spray pipe. Because the top of the scraped condenser's vertical cylinder is connected to the vacuum system, hot glycol readily evaporates under vacuum when sprayed, preventing the capture of condensable gases and entrained matter. Therefore, the present invention positions the cold glycol spray point above the hot glycol spray point, allowing the cold glycol to cover the hot glycol, condensable gases, and entrained matter within the vertical cylinder, thereby preserving the spraying effect and achieving online cleaning of the spray pipe interior.

[0027] As the preferred technical solution:

[0028] As described above, a circulating spray system for ethylene glycol has a vacuum suction port on the top of the vertical cylinder, which is used to connect to the vacuum system; a discharge port is provided at the bottom of the horizontal cylinder, which is connected to the liquid sealing tank through a lower liquid pipe; the liquid sealing tank is used to receive and filter ethylene glycol.

[0029] The ethylene glycol circulating spray system as described above further comprises a cone-shaped distribution plate I and a cone-shaped distribution plate II;

[0030] The cone-shaped distribution plate II is located inside the vertical cylinder. The output end of the spray pipe is inserted into the vertical cylinder, with the orifice of the output end of the spray pipe facing the top of the cone-shaped distribution plate II. The cone-shaped distribution plate II is used to evenly spray the ethylene glycol sprayed from the spray pipe into the vertical cylinder.

[0031] The conical cap type distribution plate I is located above the conical cap type distribution plate II; a through hole II is provided on the conical cap type distribution plate I, and the output end of the spray pipe passes through the through hole II and is fixedly connected to the through hole II.

[0032] The ethylene glycol circulating spray system as described above further comprises an additional pipe III, an additional pipe IV, an additional pipe V and an atomizing nozzle;

[0033] Assume that there is a connection point P between the spray pipe and the plate heat exchanger II on the circulation pipe II; one end of the external pipe III is connected to the jacket spray pipe, and the other end is connected to the connection point P; a valve a is provided on the circulation pipe II between the connection point P and the spray pipe;

[0034] Assume that there is a connection point Q between the spray pipe and the plate heat exchanger I on the circulation pipe I; one end of the external pipe IV is connected to the connection point Q, and the other end is used to pass hot ethylene glycol above 120°C; a valve e is provided on the external pipe IV;

[0035] The external pipe I is provided with a valve d, and the external pipe III is provided with a valve c;

[0036] The atomizing nozzle is located inside the vertical cylinder and above the conical cap distribution plate I. One end of the external tube V is inserted into the vertical cylinder and connected to the atomizing nozzle. The other end of the external tube V is used to introduce fresh ethylene glycol I. A valve y is provided on the external tube V.

[0037] When cleaning the inner wall of the jacket spray pipe, hot glycol flows through the jacket spray pipe, while cold glycol flows through the spray pipe. At this point, the hot glycol sprays above the cold glycol, preventing it from effectively covering the hot glycol. Therefore, valve y needs to be opened to allow fresh glycol I to enter the vertical cylinder for spraying, thereby covering the hot glycol. Furthermore, fresh glycol I can reduce the concentration of impurities in the recycled glycol, thereby reducing adverse effects such as scaling.

[0038] When there are additional pipes I, II, III and IV, hot ethylene glycol can be introduced into the circulation pipe I to clean the interior of the spray pipe (in this case, the cold ethylene glycol in the circulation pipe II goes to the jacket spray pipe), or hot ethylene glycol can be introduced into the circulation pipe II to clean the interior of the spray pipe (in this case, the cold ethylene glycol in the circulation pipe I goes to the jacket spray pipe); similarly, hot ethylene glycol can be introduced into the circulation pipe I to clean the interior of the jacket spray pipe (in this case, the cold ethylene glycol in the circulation pipe II goes to the spray pipe), or hot ethylene glycol can be introduced into the circulation pipe II to clean the interior of the jacket spray pipe (in this case, the cold ethylene glycol in the circulation pipe I goes to the spray pipe).

[0039] In the above-mentioned ethylene glycol circulating spraying system, a connection point R is provided on the external pipe I between the valve d and the spraying pipe, one end of the external pipe III is connected to the connection point R, and the other end is connected to the connection point P.

[0040] The ethylene glycol circulating spray system as described above further comprises an additional pipe VI, an additional pipe VII and an additional pipe VIII;

[0041] The end of external tube II not connected to connection point O and the end of external tube IV not connected to connection point Q are connected to one end of external tube VI via a tee, and external tubes VII and VIII are connected to the other end of external tube VI via a tee. External tube VII is provided with a valve g, and external tube VIII is provided with a valve h. The end of external tube VII not connected to external tube VI is used to introduce hot ethylene glycol at 170°C to 180°C, and the end of external tube VIII not connected to external tube VI is used to introduce fresh ethylene glycol II.

[0042] A mixer is provided on the external pipe VI, which is used to mix hot ethylene glycol at 170°C to 180°C and fresh ethylene glycol II into hot ethylene glycol at 120°C to 140°C; a thermometer is provided on the mixer, which is used to detect the temperature inside the mixer;

[0043] During the polyester polymerization process, hot ethylene glycol at 170℃~180℃ will be produced as a by-product. In order to recycle it, hot ethylene glycol at 170℃~180℃ is introduced. However, if the hot ethylene glycol is too hot and is directly introduced, it will have an adverse effect on the pipeline. Therefore, fresh ethylene glycol II is added to neutralize and cool it down. A large amount of fresh ethylene glycol can be introduced first, and then the proportion of fresh ethylene glycol II added can be gradually reduced to gradually increase the temperature of the hot ethylene glycol in the mixer from a lower temperature to 120℃~140℃.

[0044] The ethylene glycol circulating spray system as described above further comprises a connecting plate I, a connecting plate II, an expanding pipe, a fixing ring and a plurality of fixing plates;

[0045] The fixing ring is sleeved on the jacket spray pipe and is fixedly connected to the jacket spray pipe; the fixing ring is fixedly connected to the inner wall of the vertical cylinder through the connecting plate I to better fix the jacket spray pipe;

[0046] The cone-shaped distribution plate II is fixedly connected to the inner wall of the vertical cylinder through the connecting plate II to better fix the cone-shaped distribution plate II;

[0047] One end of the jacketed spray pipe inserted into the interior of the vertical cylinder is fixedly connected to the small end of the expansion pipe, and the large end of the expansion pipe faces the top of the conical cap distribution plate 1. The expansion pipe and the conical cap distribution plate 1 are used in conjunction to spray ethylene glycol to form a better liquid curtain;

[0048] The fixing plate is located inside the jacket spray pipe, the fixing plate is fixedly connected to the outer wall of the spray pipe, and there is a gap between the fixing plate and the inner wall of the jacket spray pipe;

[0049] The fixing plate is used to support the jacketed spray pipe. The reason why it is not directly fixed to the inner wall of the jacketed spray pipe is that when the temperature difference between the spray pipe and the ethylene glycol flowing in the jacketed spray pipe is large, the pipe will expand and contract greatly due to the temperature, and a direct fixed connection will cause damage to the pipe.

[0050] In the above-mentioned ethylene glycol circulating spraying system, a cone is provided on the top of the conical cap distribution plate II, and the cone is inserted into the spray pipe from the orifice at the output end of the spray pipe; the design of the cone allows the ethylene glycol sprayed toward the spray pipe to form a better liquid curtain.

[0051] In the above-described ethylene glycol circulation spraying system, along the direction from the liquid seal tank 46 to the spray pipe, the circulation pipe 1 is sequentially provided with a valve s, a filter 1, a pump 1, a valve n, a plate heat exchanger 1, and a valve b; the pump 1 is used to transport the ethylene glycol in the liquid seal tank to the spray pipe; the plate heat exchanger 1 is used to cool the ethylene glycol;

[0052] Along the direction from the liquid seal tank to the spray pipe I, the circulation pipe II is sequentially provided with valve r, filter II, pump II, valve q, plate heat exchanger II, and valve a; pump II is used to transport the ethylene glycol in the liquid seal tank to the spray pipe; plate heat exchanger II is used to cool the ethylene glycol.

[0053] The ethylene glycol circulating spraying system as described above further comprises a switching pipe I, a switching pipe II, a production pipe I and a production pipe II;

[0054] Assume that there is a connection point A on circulation pipe I between pump I and valve n, and a connection point B on circulation pipe I between valve n and plate heat exchanger I; assume that there is a connection point C on circulation pipe II between pump II and valve q, and a connection point D on circulation pipe II between valve q and plate heat exchanger II; one end of switching pipe I is connected to connection point A, the other end of switching pipe I is connected to connection point D, and switching pipe I is provided with valve o; one end of switching pipe II is connected to connection point B, and the other end is connected to connection point C; switching pipe II is provided with valve p;

[0055] Assume that there is a connection point E on the circulation pipe I between the plate heat exchanger I and the valve b, and that there is a connection point F on the circulation pipe II between the plate heat exchanger II and the valve a; one end of the production pipe I is connected to the connection point E, and the other end is connected to the outside world; along the direction from the connection point E to the outside world, valves k and m are sequentially provided on the production pipe I; the input end of the production pipe II is connected to the connection point F, and the output end of the production pipe II is connected to the production pipe I between valves k and valves m; and a valve l is provided on the production pipe II;

[0056] When there is too much ethylene glycol in the liquid seal tank (ethylene glycol vapor in the exhaust gas is captured and falls into the circulation system), valves k, l, and m are controlled to maintain a stable flow in the circulation system. The design of switching pipes I and II prevents the problem of being unable to spray ethylene glycol due to partial pipeline damage.

[0057] The ethylene glycol circulating spray system as described above further comprises a circulating pipe III, a circulating pipe IV and a circulating pipe V;

[0058] Assume that a connection point G is provided on circulation pipe II between valve r and filter II, and a connection point H is provided on circulation pipe II between connection point F and valve a. One end of circulation pipe III is connected to connection point G, and the other end is connected to connection point H. A jacketed heat exchanger is provided on circulation pipe III; the jacketed heat exchanger is used to heat hexylene glycol. A valve u is provided on circulation pipe III between the jacketed heat exchanger and connection point G, and a valve w is provided on circulation pipe III between the jacketed heat exchanger and connection point H.

[0059] Assume that there is a connection point I between valve s and filter I on circulation pipe I, and a connection point J between connection point E and valve b; one end of circulation pipe IV is connected to connection point I, and the other end is connected to the area between valve u and the jacketed heat exchanger on circulation pipe II; circulation pipe IV is provided with a valve t; one end of circulation pipe V is connected to connection point J, and the other end is connected to the area between valve w and the jacketed heat exchanger on circulation pipe III; circulation pipe V is provided with a valve x;

[0060] When online cleaning of the circulation pipe I is required, the valve is controlled so that the circulation pipe I, the circulation pipe IV, a part of the circulation pipe III, and the circulation pipe V form an online cleaning circulation system, thereby achieving the cleaning of the circulation pipe I, while the circulation pipe II is still participating in the ethylene glycol spraying; when online cleaning of the circulation pipe II is required, the valve is controlled so that the circulation pipe II and the circulation pipe III form an online cleaning circulation system, thereby achieving the cleaning of the circulation pipe II, while the circulation pipe I is still participating in the ethylene glycol spraying; as set up above, the online cleaning of the circulation pipes I and II can be achieved.

[0061] The ethylene glycol circulating spray system as described above further includes a buffer tank, a feeding pipe and an overflow pipe;

[0062] Assume that there is a connection point K between valve w and the jacketed heat exchanger on the circulation pipe III, a connection point L between valves k and valve m on the production pipe I, and a connection point M between valve m and the outlet of the production pipe I. One end of the feed pipe is connected to the connection point K, and the other end is connected to the connection point L. The buffer tank is installed on the feed pipe; one end of the overflow pipe is connected to the buffer tank, and the other end is connected to the connection point M. The feed pipe is also equipped with a valve v. When the liquid in the buffer tank overflows, the valve v is closed, and the addition of ethylene glycol is stopped.

[0063] During the online cleaning process of the circulation pipe I and the circulation pipe II, the ethylene glycol in the circulation pipe that is being sprayed can be introduced into the circulation pipe that is being cleaned online through the replenishing pipe, so that the circulation pipe that is being cleaned online can be further filled with ethylene glycol (when ethylene glycol overflows from the buffer tank 47 through the overflow pipe, it is filled).

[0064] In the above-mentioned ethylene glycol circulating spraying system, the connection point N is located between the valve b and the connection point Q, the connection point Q is located between the connection point N and the connection point E; the connection point O is located between the connection point H and the connection point F; and the connection point P is located between the spray pipe and the connection point H.

[0065] The ethylene glycol circulating spraying system as described above further comprises a flow meter I, a flow meter II, a valve i and a valve j;

[0066] Valve i and flowmeter I are set on the circulation pipe I; flowmeter I is located between the connection point Q and valve i, and valve i is located between the connection point N and flowmeter I;

[0067] Valve j and flow meter II are set on the circulation pipe II; flow meter II is located between valve j and connection point O, and valve j is located between connection point H and connection point O;

[0068] Flowmeter I and flowmeter II are used to detect the spray flow of the spray pipe and the jacket spray pipe during cleaning, respectively. Valve i and valve j are used to adjust the flow rate according to the corresponding flowmeter.

[0069] Beneficial effects:

[0070] (1) The present invention can control the cold ethylene glycol to cover the hot ethylene glycol and the condensable gas and entrained matter by controlling the valve, thereby achieving the purpose of online cleaning inside the spray pipe without reducing the spraying effect.

[0071] (2) The present invention can control the hot ethylene glycol to flow into the circulation pipe I and the circulation pipe II through the external pipe I, the external pipe II, the external pipe III and the external pipe IV, so as to achieve online cleaning of the interior of the spray pipe, the jacketed spray pipe, the circulation pipe I and the circulation pipe II. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 A schematic diagram of a prior art ethylene glycol circulation spraying system;

[0073] Figure 2 Schematic diagram of the ethylene glycol circulation spraying system of the present invention;

[0074] Figure 3 It is a partial schematic diagram of the ethylene glycol circulation spraying system of the present invention;

[0075] Figure 4 This is a cross-sectional view of the jacketed spray pipe of the present invention after being sleeved on the spray pipe;

[0076] Figure 5 Schematic diagram of the cooperation between the cone-hat type distribution plate I and the cone-hat type distribution plate II of the present invention;

[0077] Among them, 1- spray pipe, 2- jacketed spray pipe, 3- external pipe I, 4- fixed plate, 5- cone-shaped distribution plate I, 6- cone-shaped distribution plate II, 7- cone, 8- connecting plate I, 9- connecting plate II, 10- expansion pipe, 11- fixed ring, 12- vertical cylinder, 13- valve a, 14- valve b, 15- valve c, 16- valve d, 17- valve e, 18- valve f, 19- temperature gauge, 20- mixer, 21- valve g, 22- valve h, 23- valve i, 24- valve j, 25- flow meter I, 26- flow meter II, 27- valve k, 28- valve l, 29- valve m, 30- plate heat exchanger I, 31- plate heat exchanger II, 32- valve n, 33- valve o, 34- valve p, 35- valve q, 36-pump I, 37-pump II, 38-filter I, 39-filter II, 40-valve r, 41-valve s, 42-valve t, 43-valve u, 44-jacketed heat exchanger, 45-horizontal cylinder, 46-liquid seal tank, 47-buffer tank, 48-valve v, 49-valve w, 50-valve x, 51-valve y, 52-connection point A, 53-connection point B, 54-connection point C, 55-connection point D, 56-connection point E, 57-connection point F, 58-connection point G, 59-connection point H, 60-connection point I, 61-connection point J, 62-connection point K, 63-connection point L, 64 connection point M, 65-connection point N, 66-connection point O, 67-connection point P, 68-connection point Q, 69-connection point R. DETAILED DESCRIPTION

[0078] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0079] A glycol circulation spray system, such as Figures 2 to 5 As shown, it includes a spray pipe 1, a scraper condenser, a downpipe, a liquid seal tank 46, a circulation pipe I, a circulation pipe II, a jacketed spray pipe 2, a conical cap distribution plate I 5, an additional pipe I 3, an additional pipe II, an additional pipe III, an additional pipe IV, an additional pipe V, an atomizing nozzle, an additional pipe VI, an additional pipe VII, an additional pipe VIII, a connecting plate I 8, a connecting plate II 9, an expanding pipe 10, a fixing ring 11, a plurality of fixing plates 4, a switching pipe I, a switching pipe II, a production pipe I, a production pipe II, a circulation pipe III, a circulation pipe IV, a circulation pipe V, a buffer tank 47, a feeding pipe and an overflow pipe;

[0080] The scraped surface condenser comprises a horizontal cylinder 45, a vertical cylinder 12 and a conical cap type distribution plate II 6;

[0081] A vacuum suction port is provided on the top of the vertical cylinder 12, and the vacuum suction port is used to connect to the vacuum system;

[0082] A discharge port is provided at the lower portion of the horizontal cylinder 45; the discharge port is connected to a liquid seal tank 46 via a lower liquid pipe; the liquid seal tank 46 is used to receive and filter ethylene glycol;

[0083] like Figures 3 to 5 As shown, a cone is provided on the top of the cone-shaped distribution plate II 6, and the cone-shaped distribution plate II 6 is fixedly connected to the inner wall of the vertical cylinder 12 through the connecting plate II 9;

[0084] The cone-shaped distribution plate I 5 is located above the cone-shaped distribution plate II 6, and a through hole II is provided on the cone-shaped distribution plate I 5;

[0085] The output end of the spray pipe 1 is inserted into the vertical cylinder 12 and passes through the through hole II, where it is fixedly connected. The orifice of the output end of the spray pipe 1 faces the top of the conical cap distribution plate II 6, and the cone is inserted into the spray pipe 1 through the orifice of the output end of the spray pipe 1. The conical cap distribution plate II 6 is used to evenly spray the ethylene glycol sprayed from the spray pipe 1 into the vertical cylinder 12.

[0086] The jacketed spray pipe 2 is sleeved on the spray pipe 1; one end of the jacketed spray pipe 2 is sealed with the spray pipe 1, and the other end is inserted into the interior of the vertical cylinder 12 and fixedly connected to the small end of the expansion pipe 10, and the large end of the expansion pipe 10 faces the top of the conical cap distribution plate 15;

[0087] The fixing plate 4 is located inside the jacket spray pipe 2, and the fixing plate 4 is fixedly connected to the outer wall of the spray pipe 1, and there is a gap between the fixing plate 4 and the inner wall of the jacket spray pipe 2;

[0088] The fixing ring 11 is sleeved on the jacket spray pipe 2 and is fixedly connected to the jacket spray pipe 2; the fixing ring 11 is fixedly connected to the inner wall of the vertical cylinder 12 through the connecting plate I8;

[0089] The atomizing nozzle is located inside the vertical cylinder 12 and above the conical cap distribution plate 15. One end of the external tube V is inserted into the vertical cylinder 12 and connected to the atomizing nozzle. The other end of the external tube V is used to introduce fresh ethylene glycol I. A valve y 51 is provided on the external tube V.

[0090] like Figure 2 、 Figure 3 As shown, one end of the circulation pipe I and the circulation pipe II are respectively connected to the liquid seal groove 46, and the other end is respectively connected to the input end of the spray pipe 1;

[0091] Along the direction from liquid seal tank 46 to spray pipe 1, circulation pipe 1 is sequentially provided with valve s 41, filter 1 38, pump 1 36, valve n 32, plate heat exchanger 1 30, flowmeter 1 25, valve i 23, and valve b 14. Pump 1 36 is used to transport ethylene glycol in liquid seal tank 46 to spray pipe 1; plate heat exchanger 1 30 is used to cool ethylene glycol.

[0092] Along the direction from liquid seal tank 46 to spray pipe I1, circulation pipe II is sequentially equipped with valve r 40, filter II 39, pump II 37, valve q 35, plate heat exchanger II 31, flowmeter II 26, valve j 24, and valve a 13. Pump II 37 is used to transport ethylene glycol in liquid seal tank 46 to spray pipe 1; plate heat exchanger II 31 is used to cool the ethylene glycol.

[0093] Assume that on circulation pipe I, there is a connection point A 52 between pump I 36 and valve n 32, and on circulation pipe I, there is a connection point B 53 between valve n 32 and plate heat exchanger I 30; on circulation pipe II, there is a connection point C 54 between pump II 37 and valve q 35, and on circulation pipe II, there is a connection point D 55 between valve q 35 and plate heat exchanger II 31; one end of switching pipe I is connected to connection point A 52, and the other end of switching pipe I is connected to connection point D 55, and switching pipe I is provided with valve o 33; one end of switching pipe II is connected to connection point B 53, and the other end is connected to connection point C 54, and switching pipe II is provided with valve p 34;

[0094] Assume that a connection point E 56 is provided on circulation pipe I between plate heat exchanger I 30 and valve b 14, and a connection point F 57 is provided on circulation pipe II between plate heat exchanger II 31 and valve a 13. One end of production pipe I is connected to connection point E 56, and the other end is connected to the outside world. Valve k 27 and valve m 29 are provided on production pipe I in sequence, extending from connection point E 56 to the outside world. The input end of production pipe II is connected to connection point F 57, and the output end of production pipe II is connected to production pipe I between valves k 27 and m 29. Valve l 28 is provided on production pipe II.

[0095] Assume that a connection point G 58 is provided on circulation pipe II between valve r 40 and filter II 39, and a connection point H 59 is provided on circulation pipe II between connection point F 57 and valve a 13. Circulation pipe III is connected to connection point G 58 at one end and to connection point H 59 at the other end. A jacketed heat exchanger 44 is provided on circulation pipe III; jacketed heat exchanger 44 is used to heat hexylene glycol. A valve u 43 is provided on circulation pipe III between jacketed heat exchanger 44 and connection point G 58, and a valve w 49 is provided on circulation pipe III between jacketed heat exchanger 44 and connection point H 59.

[0096] Assume that on circulation pipe I, there is a connection point I 60 between valve s 41 and filter I 38, and a connection point J 61 between connection point E 56 and valve b14. Circulation pipe IV has one end connected to connection point I 60 and the other end connected between valve u 43 and jacketed heat exchanger 44 on circulation pipe II. Circulation pipe IV is provided with valve t 42. Circulation pipe V has one end connected to connection point J 61 and the other end connected between valve w 49 and jacketed heat exchanger 44 on circulation pipe III. Circulation pipe V is provided with valve x 50.

[0097] Assume that a connection point O 66 is located on the circulation pipe II between the spray pipe 1 and the plate heat exchanger II 31; one end of the external pipe II is connected to the connection point O 66, and the other end is connected to one end of the external pipe VI via a tee; a valve f 18 is provided on the external pipe II;

[0098] Assume that a connection point P67 is located on circulation pipe II between spray pipe 1 and plate heat exchanger II 31. A connection point R69 is located on external pipe I3 ​​between valve d16 and spray pipe 1. One end of external pipe III is connected to connection point R69 and the other end is connected to connection point P67. A valve c15 is located on external pipe III. A valve a13 is located on circulation pipe II between connection point P67 and spray pipe 1.

[0099] A mixer 20 is provided on the external pipe VI. The mixer 20 is used to mix hot ethylene glycol at 170°C to 180°C and fresh ethylene glycol II into hot ethylene glycol at 120°C to 140°C. A thermometer 19 is provided on the mixer 20 to detect the temperature inside the mixer 20.

[0100] External tube VII and external tube VIII are connected to the other end of external tube VI via a tee. External tube VII is provided with a valve g 21, and external tube VIII is provided with a valve h 22. The end of external tube VII not connected to external tube VI is used to introduce hot ethylene glycol at 170°C to 180°C, and the end of external tube VIII not connected to external tube VI is used to introduce fresh ethylene glycol II.

[0101] A connection point N 65 is provided on the circulation pipe I between valve b 14 and connection point Q 68. One end of an additional pipe I 3 is connected to the jacketed spray pipe 2, and the other end is connected to connection point N 65. A valve d 16 is provided on the additional pipe I 3.

[0102] Assume that a connection point Q68 is located on the circulation pipe I between the spray pipe 1 and the plate heat exchanger I30. One end of the external pipe IV is connected to the connection point Q68, and the other end is connected to one end of the external pipe VI via a tee. A valve e17 is provided on the external pipe IV.

[0103] Valve i 23 and flow meter I 25 are provided on the circulation pipe I; flow meter I 25 is located between connection point Q 68 and valve i 23, and valve i 23 is located between connection point N 65 and flow meter I 25;

[0104] Connection point Q 68 is located between connection point N 65 and connection point E 56;

[0105] Connection point O 66 is located between connection point H 59 and connection point F 57; connection point P 67 is located between spray pipe 1 and connection point H 59;

[0106] Valve j 24 and flow meter II 26 are provided on circulation pipe II; flow meter II 26 is located between valve j 24 and connection point O 66, and valve j 24 is located between connection point H 59 and connection point O 66;

[0107] Assume that there is a connection point K62 between valve w49 and jacketed heat exchanger 44 on circulation pipe III, a connection point L63 between valve k27 and valve m29 on production pipe I, and a connection point M64 between valve m29 and the discharge outlet of production pipe I on production pipe I; one end of the feed pipe is connected to connection point K62, and the other end is connected to connection point L63; buffer tank 47 is arranged on the feed pipe; one end of the overflow pipe is connected to buffer tank 47, and the other end is connected to connection point M64; valve v48 is also provided on the feed pipe.

[0108] The use process of the above device is as follows: Figure 2 As shown, during the polyester production process, the tail gas generated by the polycondensation reaction will pass through the scraper condenser to remove the condensable gas and entrained matter, so that only the non-condensable gas enters the vacuum system through the vacuum suction port. During this process, as the scraper condenser is used for a long time, small substances are not easy to be removed and will adhere to the spray pipe 1, the jacketed spray pipe 2 and the inner tube of the circulation pipe. At this time, the above-mentioned device is required to clean them.

[0109] Due to the presence of the additional pipes I 3, II, III, and IV, both hot and cold ethylene glycol can be introduced into the circulation pipes I and II of the present invention. Therefore, only some usage scenarios are described below as examples:

[0110] When the inner tube of the spray pipe 1 needs to be cleaned, first close valves r 40, t 42, and u 43, then open valve d 16 and close valve b 14 at the same time, allowing the cold ethylene glycol in the circulation pipe I to enter the jacketed spray pipe 2 and spray out from the large end of the expansion pipe. Then open valve h 22 to pass fresh ethylene glycol II into the mixer 20, then open valve f 18, j 24, and a 13 to pass fresh ethylene glycol II into the circulation pipe II and the spray pipe 1 and spray out from the output end of the spray pipe 1, then open valve g Hot ethylene glycol at a temperature of 170°C to 180°C is introduced into the mixer 21, so that the temperature of the hot ethylene glycol in the mixer 20 gradually rises from a relatively low temperature to 120°C to 140°C, ensuring that the cold ethylene glycol can cover the hot ethylene glycol and the condensable gas and entrained matter. The sprayed ethylene glycol, condensed gas and entrained matter then pass through the discharge port of the horizontal cylinder 45 and enter the liquid seal tank 46, where they are filtered and then recycled. In this way, online cleaning of the interior of the spray pipe 1 and the circulation pipe II can be achieved without reducing the spraying effect.

[0111] When the inner tube of the jacket spray pipe 2 needs to be cleaned, first ensure that cold ethylene glycol is circulated and sprayed normally from the spray pipe 1 through the circulation pipe I via the valve b 14, then close the valve r 40, valve t 42, valve u 43, and valve a 13, and then open the valve h22 to pass fresh ethylene glycol II into the mixer 20, then open the valve f 18, valve j 24, and valve c 15, and pass the fresh ethylene glycol II into the circulation pipe II and the jacket spray pipe 2 and spray it out from the large end of the expansion pipe, then open the valve g 21 to pass hot ethylene glycol at a temperature of 170℃~180℃ so that the temperature of the hot ethylene glycol in the mixer 20 gradually rises from a lower temperature to 120℃~140℃, and at the same time open the valve y 51, allowing fresh ethylene glycol I to enter the vertical cylinder 12 for spraying, thereby covering the hot ethylene glycol, and then the sprayed ethylene glycol, condensed gas and entrained matter enter the liquid seal tank 46 after passing through the discharge port of the horizontal cylinder 45 and are filtered and then continued to be recycled. In this way, the online cleaning of the jacket spray pipe 2 and the circulation pipe II can be achieved without reducing the spraying effect.

Claims

1. A circulation spraying system for ethylene glycol, comprising a spray pipe (1), a scraper condenser, a downpipe, a liquid seal groove (46), a circulation pipe I and a circulation pipe II; the scraper condenser comprises a horizontal cylinder (45) and a vertical cylinder (12); the output end of the spray pipe (1) is inserted into the vertical cylinder (12); one end of the circulation pipe I and the circulation pipe II are respectively connected to the liquid seal groove (46), and the other end is respectively connected to the input end of the spray pipe (1); the circulation pipe I is provided with a valve s (41), a pump I (36) and a plate heat exchanger I (30); the circulation pipe II is provided with a valve r (40), a pump II (37) and a plate heat exchanger II (31); the valve s (41) is located between the plate heat exchanger I (30) and the liquid seal groove (46), and the valve r (40) is located between the plate heat exchanger II (31) and the liquid seal groove (46); the characteristic is that The ethylene glycol circulation spraying system further comprises a jacketed spraying pipe (2), an external pipe I (3), an external pipe II, a cone-shaped distribution plate I (5), a cone-shaped distribution plate II (6), a connecting plate I (8), a connecting plate II (9), an expanding pipe (10), a fixing ring (11) and a plurality of fixing plates (4); The jacketed spray pipe (2) is sleeved on the spray pipe (1); one end of the jacketed spray pipe (2) is sealedly connected to the spray pipe (1), and the other end is inserted into the interior of the vertical cylinder (12); Assume that a connection point N (65) is provided between the spray pipe (1) and the plate heat exchanger I (30) on the circulation pipe I; one end of the external pipe I (3) is connected to the jacketed spray pipe (2), and the other end is connected to the connection point N (65); a valve b (14) is provided on the circulation pipe I between the connection point N (65) and the spray pipe (1); Assume that a connection point O (66) is provided between the spray pipe (1) and the plate heat exchanger II (31) on the circulation pipe II; one end of the external pipe II is connected to the connection point O (66), and the other end is used to introduce hot ethylene glycol above 120° C.; a valve f (18) is provided on the external pipe II; The cone-shaped distribution plate II (6) is located inside the vertical cylinder (12); the output end of the spray pipe (1) is inserted into the vertical cylinder (12), and the orifice of the output end of the spray pipe (1) faces the top of the cone-shaped distribution plate II (6); the cone-shaped distribution plate II (6) is used to evenly spray the ethylene glycol sprayed from the spray pipe (1) inside the vertical cylinder (12); The cone-shaped distribution plate I (5) is located above the cone-shaped distribution plate II (6); a through hole II is provided on the cone-shaped distribution plate I (5); the output end of the spray pipe (1) passes through the through hole II and is fixedly connected to the through hole II; The fixing ring (11) is sleeved on the jacket spray pipe (2) and fixedly connected to the jacket spray pipe (2); the fixing ring (11) is fixedly connected to the inner wall of the vertical cylinder (12) through the connecting plate I (8); The cone-shaped distribution plate II (6) is fixedly connected to the inner wall of the vertical cylinder (12) via the connecting plate II (9); One end of the jacketed spray pipe (2) inserted into the interior of the vertical cylinder (12) is fixedly connected to the small end of the expansion pipe (10), and the large end of the expansion pipe (10) faces the top of the cone-shaped distribution plate I (5); The fixing plate (4) is located inside the jacketed spray pipe (2), the fixing plate (4) is fixedly connected to the outer wall of the spray pipe (1), and a gap exists between the fixing plate (4) and the inner wall of the jacketed spray pipe (2).

2. The ethylene glycol circulation spraying system according to claim 1, characterized in that: A vacuum suction port is provided at the top of the vertical cylinder (12), which is used to connect to a vacuum system; a discharge port is provided at the bottom of the horizontal cylinder (45), which is connected to a liquid sealing tank (46) through a lower liquid pipe; and the liquid sealing tank (46) is used to receive and filter ethylene glycol.

3. The ethylene glycol circulation spraying system according to claim 2, characterized in that: The ethylene glycol circulation spraying system also includes an additional pipe III, an additional pipe IV, an additional pipe V and an atomizing nozzle; Assume that a connection point P (67) is provided between the spray pipe (1) and the plate heat exchanger II (31) on the circulation pipe II; one end of the external pipe III is connected to the jacket spray pipe (2), and the other end is connected to the connection point P (67); a valve a (13) is provided on the circulation pipe II between the connection point P (67) and the spray pipe (1); Assume that a connection point Q (68) is provided between the spray pipe (1) and the plate heat exchanger I (30) on the circulation pipe I; one end of the external pipe IV is connected to the connection point Q (68), and the other end is used to pass hot ethylene glycol above 120° C.; a valve e (17) is provided on the external pipe IV; The external pipe I (3) is provided with a valve d (16), and the external pipe III is provided with a valve c (15); The atomizing nozzle is located inside the vertical cylinder (12) and above the conical cap type distribution plate I (5); one end of the external tube V is inserted into the vertical cylinder (12) and connected to the atomizing nozzle, and the other end of the external tube V is used to introduce fresh ethylene glycol I; a valve y (51) is provided on the external tube V.

4. The ethylene glycol circulation spraying system according to claim 3, characterized in that: Assume that a connection point R (69) is provided on the external pipe I (3) between the valve d (16) and the spray pipe (1), one end of the external pipe III is connected to the connection point R (69), and the other end is connected to the connection point P (67).

5. The ethylene glycol circulation spraying system according to claim 4, characterized in that: The glycol circulation spraying system also includes an additional pipe VI, an additional pipe VII and an additional pipe VIII; The end of the external pipe II not connected to the connection point O (66) and the end of the external pipe IV not connected to the connection point Q (68) are connected to one end of the external pipe VI through a tee, and the external pipe VII and the external pipe VIII are connected to the other end of the external pipe VI through a tee; a valve g (21) is provided on the external pipe VII, and a valve h (22) is provided on the external pipe VIII; the end of the external pipe VII not connected to the external pipe VI is used to introduce hot ethylene glycol at 170° C. to 180° C., and the end of the external pipe VIII not connected to the external pipe VI is used to introduce fresh ethylene glycol II; The external pipe VI is provided with a mixer (20), which is used to mix hot ethylene glycol at 170° C. to 180° C. and fresh ethylene glycol II into hot ethylene glycol at 120° C. to 140° C.; the mixer (20) is provided with a thermometer (19), which is used to detect the temperature inside the mixer (20).

6. The ethylene glycol circulation spraying system according to claim 5, characterized in that: A cone is provided on the top of the cone-hat type distribution plate II (6), and the cone is inserted into the spray pipe (1) from the orifice at the output end of the spray pipe (1).

7. The ethylene glycol circulation spraying system according to claim 6, characterized in that: Along the direction from the liquid seal tank 46 to the spray pipe (1), the circulation pipe I is provided with a valve s (41), a filter I (38), a pump I (36), a valve n (32), a plate heat exchanger I (30) and a valve b (14) in sequence; the pump I (36) is used to transport the ethylene glycol in the liquid seal tank (46) to the spray pipe (1); the plate heat exchanger I (30) is used to cool the ethylene glycol; Along the direction from the liquid seal tank (46) to the spray pipe (1), the circulation pipe II is provided with a valve r (40), a filter II (39), a pump II (37), a valve q (35), a plate heat exchanger II (31), and a valve a (13) in sequence; the pump II (37) is used to transport the ethylene glycol in the liquid seal tank (46) to the spray pipe (1); and the plate heat exchanger II (31) is used to cool the ethylene glycol.

8. The ethylene glycol circulation spraying system according to claim 7, characterized in that: The ethylene glycol circulation spraying system also includes a switching pipe I, a switching pipe II, a production pipe I and a production pipe II; Assume that there is a connection point A (52) between the pump I (36) and the valve n (32) on the circulation pipe I, and a connection point B (53) between the valve n (32) and the plate heat exchanger I (30) on the circulation pipe I; assume that there is a connection point C (54) between the pump II (37) and the valve q (35) on the circulation pipe II, and a connection point D (55) between the valve q (35) and the plate heat exchanger II (31) on the circulation pipe II; one end of the switching pipe I is connected to the connection point A (52), the other end of the switching pipe I is connected to the connection point D (55), and the switching pipe I is provided with a valve o (33); one end of the switching pipe II is connected to the connection point B (53), and the other end is connected to the connection point C (54); the switching pipe II is provided with a valve p (34); Assume that a connection point E (56) is provided on the circulation pipe I between the plate heat exchanger I (30) and the valve b (14), and a connection point F (57) is provided on the circulation pipe II between the plate heat exchanger II (31) and the valve a (13); one end of the production pipe I is connected to the connection point E (56), and the other end is connected to the outside world; along the direction from the connection point E (56) to the outside world, a valve k (27) and a valve m (29) are provided on the production pipe I in sequence; the input end of the production pipe II is connected to the connection point F (57), and the output end of the production pipe II is connected to the production pipe I between the valve k (27) and the valve m (29); and a valve l (28) is provided on the production pipe II.

9. The ethylene glycol circulation spraying system according to claim 8, characterized in that: The glycol circulation spraying system also includes circulation pipe III, circulation pipe IV and circulation pipe V; Assume that a connection point G (58) is provided on the circulation pipe II between the valve r (40) and the filter II (39), and a connection point H (59) is provided on the circulation pipe II between the connection point F (57) and the valve a (13); one end of the circulation pipe III is connected to the connection point G (58), and the other end is connected to the connection point H (59); a jacket heat exchanger (44) is provided on the circulation pipe III; the jacket heat exchanger (44) is used to heat hexanediol; a valve u (43) is provided on the circulation pipe III between the jacket heat exchanger (44) and the connection point G (58), and a valve w (49) is provided on the circulation pipe III between the jacket heat exchanger (44) and the connection point H (59); Assume that a connection point I (60) is provided between valve s (41) and filter I (38) on circulation pipe I, and a connection point J (61) is provided between connection point E (56) and valve b (14); one end of circulation pipe IV is connected to connection point I (60), and the other end is connected to between valve u (43) and jacket heat exchanger (44) on circulation pipe II; circulation pipe IV is provided with valve t (42); one end of circulation pipe V is connected to connection point J (61), and the other end is connected to between valve w (49) and jacket heat exchanger (44) on circulation pipe III; circulation pipe V is provided with valve x (50).

10. The ethylene glycol circulation spraying system according to claim 9, characterized in that: The glycol circulation spraying system also includes a buffer tank (47), a feeding pipe and an overflow pipe; Assume that a connection point K (62) is provided on the circulation pipe III between the valve w (49) and the jacketed heat exchanger (44), a connection point L (63) is provided on the production pipe I between the valve k (27) and the valve m (29), and a connection point M (64) is provided on the production pipe I between the valve m (29) and the discharge port of the production pipe I; one end of the feed pipe is connected to the connection point K (62), and the other end is connected to the connection point L (63); the buffer tank (47) is provided on the feed pipe; one end of the overflow pipe is connected to the buffer tank (47), and the other end is connected to the connection point M (64).

11. The ethylene glycol circulation spraying system according to claim 10, characterized in that: The connection point N (65) is located between the valve b (14) and the connection point Q (68), and the connection point Q (68) is located between the connection point N (65) and the connection point E (56); the connection point O (66) is located between the connection point H (59) and the connection point F (57); and the connection point P (67) is located between the spray pipe (1) and the connection point H (59).

12. The ethylene glycol circulation spraying system according to claim 11, characterized in that: The glycol circulation spraying system also includes a flow meter I (25), a flow meter II (26), a valve i (23) and a valve j (24); Valve i (23) and flow meter I (25) are provided on circulation pipe I; flow meter I (25) is located between connection point Q (68) and valve i (23), and valve i (23) is located between connection point N (65) and flow meter I (25); Valve j (24) and flow meter II (26) are provided on circulation pipe II; flow meter II (26) is located between valve j (24) and connection point O (66), and valve j (24) is located between connection point H (59) and connection point O (66).

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