Waterway monitoring device for reactor for preparing ethylene glycol from natural gas

Abstract

The utility model belongs to the technical field of circulating water monitoring, and particularly relates to a waterway monitoring device for a natural gas-to-ethylene glycol reactor, a shell pass outlet of the reactor is connected with a water return pipe, a pH detector I is used for detecting the pH value of water in the water return pipe, a pH detector II is used for detecting the pH values of circulating water and water in a pool, and a regulating valve I is mounted on the water return pipe; the water return pipe is connected with a circulating water neutralizing pipe, the circulating water neutralizing pipe is provided with a regulating valve II, the circulating water neutralizing pipe, the cooler, the alkali liquor supplementing pipe and the cooler are all connected with a circulating water neutralizing tank, the circulating water neutralizing tank, the preheater and the deaerator are sequentially connected, the alkali liquor supplementing pipe is provided with a regulating valve III, and the deaerator is provided with a regulating valve II. And a valve I is mounted on a pipeline between the deaerator and the boiler water supply pipeline of the steam drum. The system can prevent oxalic acid from circulating in the system to corrode more equipment, and can also realize circulation of reactor shell pass water, so that slow shutdown of the system is realized, emergency shutdown of the system is avoided, and the service life of a catalyst is further ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of circulating water monitoring, and in particular relates to a waterway monitoring device for a natural gas to ethylene glycol reactor. Background Art

[0002] In the process of natural gas to ethylene glycol, the drum and reactor are both important large-scale equipment. Therefore, they must be monitored in real time during daily production. In addition, due to the high system pressure and the corrosiveness of the raw materials in ethylene glycol production, once the reactor tubes leak, the raw materials will enter the circulating water system, generating oxalic acid that corrodes the equipment, causing economic losses, and even causing emergency shutdowns in severe cases, thus affecting the life of the catalyst. Utility Model Content

[0003] The utility model aims to provide a waterway monitoring device for a natural gas to ethylene glycol reactor, so as to solve the problem that circulating water corrodes equipment when reactor tubes leak.

[0004] In order to achieve the above-mentioned purpose, the scheme of the utility model is as follows: a waterway monitoring device for a natural gas to ethylene glycol reactor, comprising a steam drum and a reactor, wherein the bottom outlet of the steam drum is connected to the shell side inlet of the reactor, the shell side outlet of the reactor is connected to a return pipe, the end of the return pipe away from the reactor is connected to the steam drum, and further comprising a pH detector I, a pH detector II, a cooler, a circulating water neutralization tank, an alkali solution replenishment pipe, a preheater and a deaerator, wherein the pH detector I is used to detect the pH value of water in the return water pipe, and the pH detector II is used to detect the pH value of water in the circulating water neutralization tank; a regulating device is installed on the return water pipe. Valve Ⅰ, a circulating water neutralization pipe is connected to the return pipe, a regulating valve Ⅱ is installed on the circulating water neutralization pipe, the end of the circulating water neutralization pipe away from the return pipe is connected to the inlet of the cooler, the outlet of the alkali solution replenishing pipe and the cooler are both connected to the circulating water neutralization tank, the outlet of the circulating water neutralization tank is connected to the inlet of the preheater, the outlet of the preheater is connected to the inlet of the deaerator, the outlet of the deaerator is connected to the boiler feed water pipeline of the steam drum, a water pump Ⅱ is installed on the pipeline between the circulating water neutralization tank and the preheater, a regulating valve Ⅲ is installed on the alkali solution replenishing pipe, and valve Ⅰ is installed on the pipeline between the deaerator and the boiler feed water pipeline of the steam drum.

[0005] The working principle and beneficial effect of this scheme are as follows: in this scheme, when the reactor tubes leak, the raw material dimethyl oxalate enters the shell side of the reactor and contacts with water to be hydrolyzed to generate oxalic acid, the pH detector I detects that the pH value of the water in the return pipe is reduced, the regulating valve I is closed, the regulating valve II is opened, the water in the shell side of the reactor flows into the circulating water neutralization pipe and contacts with the alkali solution in the circulating water neutralization tank after cooling, thereby neutralizing the circulating water, and the pH detector II is used to detect the pH value of the circulating water in the circulating water neutralization tank, and the neutralized circulating water is heated and deoxygenated and then sent back to the drum to realize the recycling of the reactor shell side water. In this way, this scheme can not only avoid oxalic acid from circulating in the system and corroding more equipment, but also realize the circulation of the reactor shell side water, thereby taking the reaction heat out of the reactor, realizing the slow shutdown of the system, avoiding the emergency shutdown of the system, and thus ensuring the service life of the catalyst.

[0006] Optionally, a circulating water detection pipe is connected to the return water pipe, a cooling sleeve is provided on the outer sleeve of the circulating water detection pipe, and a pH value detector I is installed on the circulating water detection pipe; the end of the circulating water detection pipe away from the return water pipe is connected to branch pipe I and branch pipe II, and regulating valve IV is installed on branch pipe I and branch pipe II; a valve II is installed on the pipeline between the circulating water neutralization tank and the preheater, the end of branch pipe I away from the circulating water detection pipe is connected to the pipeline between valve II and the preheater, and the end of branch pipe II away from the circulating water detection pipe is connected to the circulating water neutralization tank.

[0007] There is a steam-water mixture in the return water pipe. In order to avoid the influence of steam on pH detector I, this scheme connects the circulating water detection pipe to the return water pipe, and uses a cooling sleeve to cool the steam-water mixture in the circulating water detection pipe, so that the steam is converted into liquid, avoiding the influence of steam on pH detector I, and improving the accuracy of the detection result. In addition, in this scheme, when there is no leakage in the reactor tube, the reactor shell water flows into the preheater through the branch pipe I, and then flows back to the steam drum through the deaerator, realizing the recycling of the reactor shell water for detecting pH value; and when there is a leakage in the reactor tube, the reactor shell water flows into the circulating water neutralization tank through the branch pipe II, realizing the recycling of the reactor shell water for detecting pH value.

[0008] Optionally, a reverse osmosis water purifier is provided between the circulating water neutralization tank and the preheater, and the water in the circulating water neutralization tank flows into the preheater after being purified by the reverse osmosis water purifier.

[0009] In this solution, a reverse osmosis water purifier is used to remove oxalates (oxalate ions and sodium salt ions) in the circulating water after neutralization, thereby achieving water purification.

[0010] Optionally, a controller is also included, and pH detector I, pH detector II, regulating valve I, regulating valve II, regulating valve III, regulating valve IV and water pump II are all electrically connected to the controller. The controller controls the opening and closing of regulating valve I, regulating valve II and regulating valve IV according to the signal transmitted from pH detector I. The controller controls the opening of regulating valve III and the operation of water pump II according to the signal transmitted from pH detector II.

[0011] In this solution, the controller controls the operation of each regulating valve and water pump II according to the received signal, thereby realizing the rapid line change of the reactor shell side water so that it can quickly flow into the correct pipeline.

[0012] Optionally, a regulating valve V is installed on the pipeline between the circulating water neutralization tank and the preheater, and the regulating valve V is electrically connected to the controller. The controller controls the opening and closing of the regulating valve V according to the signal transmitted from the pH detector II.

[0013] In this scheme, the regulating valve V is controlled by the controller and is opened after the pH value in the circulating water neutralization tank reaches the standard, so that the water pump II can work to pump the neutralized circulating water to the preheater.

[0014] Optionally, a stirrer for stirring is provided in the circulating water neutralization tank.

[0015] In this solution, the agitator stirs the circulating water and alkali solution in the circulating water neutralization tank to fully mix the circulating water and the alkali solution, thereby accelerating the acid-base neutralization speed.

[0016] Optionally, the steam outlet of the steam drum is connected to a by-product steam pipe, and a regulating valve VI is installed on the by-product steam pipe.

[0017] In this scheme, when the reactor tubes leak, the regulating valve VI is closed to cut off the by-product steam pipe to prevent the steam in the steam network from flowing into the steam drum.

[0018] Optionally, a regulating valve VII is installed on the boiler feed water pipeline of the steam drum.

[0019] In this scheme, the flow rate of the boiler feed water pipeline is adjusted by regulating valve VII, and the boiler feed water is reduced or even stopped when leakage occurs in the reactor tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a waterway monitoring device for a natural gas to ethylene glycol reactor in Embodiment 1 of the utility model;

[0021] Figure 2 This is a structural schematic diagram of a water channel monitoring device for a natural gas to ethylene glycol reactor in Example 2 of the utility model. DETAILED DESCRIPTION

[0022] The following is further described in detail through specific implementation methods:

[0023] The marks in the drawings of the specification include: steam drum 1, reactor 2, pH detector I3, pH detector II4, cooler 5, circulating water neutralization tank 6, alkali solution replenishment pipe 7, reverse osmosis water purifier 8, preheater 9, deaerator 10, water pump I11, return pipe 12, regulating valve I13, circulating water neutralization pipe 14, regulating valve II15, regulating valve III16, agitator 17, water pump II18, regulating valve V19, valve I20, regulating valve VII21, by-product steam pipe 22, regulating valve VI23, circulating water detection pipe 24, cooling sleeve 25, branch pipe I26, branch pipe II27, regulating valve IV28, valve II29.

[0024] Embodiment 1

[0025] This embodiment is basically Figure 1 As shown: A waterway monitoring device for a natural gas to ethylene glycol reactor, comprising a steam drum 1, a reactor 2, a pH detector Ⅰ3, a pH detector Ⅱ4, a cooler 5, a circulating water neutralization tank 6, an alkali solution supplementary pipe 7, a reverse osmosis water purifier 8, a preheater 9, a deaerator 10 and a controller, the bottom outlet of the steam drum 1 is connected to the shell side inlet of the reactor 2, and a water pump Ⅰ11 is installed on the pipeline between the steam drum 1 and the shell side inlet of the reactor 2. The shell side outlet of the reactor 2 is connected to a return pipe 12, and the end of the return pipe 12 away from the reactor 2 is connected to the steam drum 1, and a regulating valve Ⅰ13 is installed on the return pipe 12.

[0026] The pH detector I3 is used to detect the pH value of the water in the return pipe 12, and the pH detector II4 is used to detect the pH value of the water in the circulating water neutralization tank 6. The return pipe 12 is connected to the circulating water neutralization pipe 14, and the circulating water neutralization pipe 14 is installed with a regulating valve II 15. The end of the circulating water neutralization pipe 14 away from the return pipe 12 is connected to the inlet of the cooler 5, and the outlets of the alkali liquid replenishment pipe 7 and the cooler 5 are both connected to the circulating water neutralization tank 6, and the alkali liquid replenishment pipe 7 is installed with a regulating valve III 16; the circulating water neutralization tank 6 is provided with a stirrer 17 for stirring, and the outlet of the circulating water neutralization tank 6 is connected to the inlet of the reverse osmosis water purifier 8, and the outlet of the reverse osmosis water purifier 8 is connected to the inlet of the preheater 9, and the outlet of the preheater 9 is connected to the inlet of the deaerator 10, and the outlet of the deaerator 10 is connected to the boiler feed water pipeline of the drum 1. A water pump II 18 and a regulating valve V 19 are installed on the pipeline between the circulating water neutralization tank 6 and the reverse osmosis water purifier 8. A valve I 20 is installed on the pipeline between the deaerator 10 and the boiler feed water pipeline of the drum 1. The valve I 20 can be a one-way valve, a manual valve or an electric control valve. In this embodiment, the valve I 20 is a one-way valve that guides water to the boiler feed water pipeline; a regulating valve VII 21 is installed on the boiler feed water pipeline of the drum 1. The steam outlet of the drum 1 is connected to a by-product steam pipe 22, and a regulating valve VI 23 is installed on the by-product steam pipe 22.

[0027] The pH detector I3, pH detector II4, regulating valve I13, regulating valve II15, regulating valve III16, regulating valve V19, regulating valve VI23 and water pump II18 are all electrically connected to the controller, and the controller controls the opening and closing of regulating valve I13, regulating valve II15 and regulating valve VI23 according to the signal transmitted from the pH detector I3, and controls the opening of regulating valve III16 and regulating valve V19 and the operation of water pump II18 according to the signal transmitted from the pH detector II4. In this embodiment, the controller is a PLC or a 51 single chip microcomputer.

[0028] When the device is in operation, boiler feed water is injected into the drum 1 through the boiler feed water pipeline, the water pump I11 is started, and water enters the shell side of the reactor 2, taking the heat released by the reaction in the tube side of the reactor 2 out of the reactor 2, and the shell side water of the reactor 2 absorbs heat and is vaporized, and returns to the drum 1 through the return pipe 12, becomes by-product steam and enters the steam network through the by-product steam pipe 22. During the process, the pH detector I3 detects the pH value of the water in the return pipe 12 in real time. When the reactor 2 tubes leak, the raw material dimethyl oxalate enters the shell side of the reactor 2 and contacts water to be hydrolyzed to generate oxalic acid, and the oxalic acid enters the return pipe 12 together with the steam-water mixture, and the pH detector I3 detects that the pH value decreases, and the pH detector I3 transmits the signal to the controller, and the controller controls the regulating valve I13 and the regulating valve VI23 to be closed immediately, and controls the regulating valve II15 to be opened immediately, so that the shell side water of the reactor 2 flows into the cooler 5 through the circulating water neutralization pipe 14, and enters the circulating water neutralization tank 6 after cooling.

[0029] At the same time, the alkali solution replenishing pipe 7 adds alkali solution (such as sodium hydroxide solution) to the circulating water neutralization tank 6. Under the action of the agitator 17, the shell side water of the reactor 2 (i.e., circulating water) quickly contacts the alkali solution to achieve acid-base neutralization. During the neutralization process, the pH detector II4 detects the pH value of the water in the circulating water neutralization tank 6 in real time, and transmits the signal to the controller. The controller controls the opening of the regulating valve III16 to adjust the flow rate of the alkali solution. When the pH value of the water in the circulating water neutralization tank 6 reaches the standard, the controller controls the regulating valve V19 to open, and controls the water pump II18 to start, and pumps the circulating water in the circulating water neutralization tank 6 to the reverse osmosis water purifier 8. After removing oxalate ions, sodium salt ions, etc., the circulating water enters the preheater 9 for heating, and then is sent to the deaerator 10 for deoxygenation, and finally sent to the steam drum 1 for recycling, thereby realizing water circulation. In addition, when the shell side water (circulating water) of reactor 2 returns to drum 1, the boiler feed water flow rate is adjusted by regulating valve VII21, thereby reducing or even stopping the boiler water supply.

[0030] To sum up, in this embodiment, once the reactor 2 tubes leak, the shell side water of the reactor 2 immediately enters the circulating water neutralization pipe 14 line, reacts with the alkali solution in the circulating water neutralization tank 6 for neutralization, and then returns to the steam drum 1 after water purification, heating and deoxygenation, so as to realize the recycling of water, avoid the circulation of oxalic acid in the system and corrode more equipment, realize the slow shutdown of the system, avoid the emergency shutdown of the system, and thus ensure the service life of the catalyst.

[0031] Embodiment 2

[0032] The difference between this embodiment and the first embodiment is that: Figure 2 As shown, in this embodiment, a circulating water detection pipe 24 is connected to the return water pipe 12, a cooling sleeve 25 is provided on the outer sleeve of the circulating water detection pipe 24, and a pH value detector I is installed on the circulating water detection pipe 24. The end of the circulating water detection pipe 24 away from the return water pipe 12 is connected to a branch pipe I 26 and a branch pipe II 27, and a regulating valve IV 28 is installed on both the branch pipe I 26 and the branch pipe II 27. A valve II 29 is installed on the pipeline between the reverse osmosis water purifier 8 and the preheater 9, and the end of the branch pipe I 26 away from the circulating water detection pipe 24 is connected to the pipeline between the valve II 29 and the preheater 9, and the end of the branch pipe II 27 away from the circulating water detection pipe 24 is connected to the circulating water neutralization tank 6. The regulating valve IV 28 is electrically connected to the controller, and the controller controls the opening and closing of the regulating valve IV 28 according to the signal transmitted by the pH detector I 3. In this embodiment, the valve II 29 can be a one-way valve, a manual valve, or an electrically controlled valve. In this embodiment, the valve II 29 is a one-way valve that guides water to the preheater 9.

[0033] When the device is in operation, boiler feed water is injected into the drum 1 through the boiler feed water pipeline, the water pump I11 is started, and the water enters the shell side of the reactor 2, taking the heat released by the reaction in the tube side of the reactor 2 out of the reactor 2, and the water in the shell side of the reactor 2 absorbs heat and is vaporized, and a part of the steam-water mixture returns to the drum 1 through the return pipe 12, becomes by-product steam and is incorporated into the steam network, and the other part of the steam-water mixture enters the circulating water detection pipe 24, and after being cooled by the cooling sleeve 25, the steam is converted into liquid, thereby avoiding the steam from affecting the pH detector I3 and improving the accuracy of the detection result. In addition, the circulating water after detection flows into the preheater 9 through the branch pipe I26, is deoxygenated by the deaerator 10 after heating, and is finally sent back to the drum 1, so as to realize the recycling of this part of the detection water.

[0034] When a leak occurs in the reactor 2 tube array, the pH detector Ⅰ3 detects a decrease in pH value, and the pH detector Ⅰ3 transmits a signal to the controller. The controller controls the regulating valve Ⅰ13 and the regulating valve Ⅵ23 to close, and controls the regulating valve Ⅱ15 to open, switching the flow route of the shell side water of the reactor 2. At the same time, the regulating valve Ⅳ28 on the branch pipe Ⅰ26 is closed, and the regulating valve Ⅳ28 on the branch pipe Ⅱ27 is opened. The detection water flows into the circulating water neutralization tank 6 through the branch pipe Ⅱ27 for neutralization, thereby realizing the recycling of the detection water.

[0035] In summary, compared with Example 1, this embodiment not only avoids the corrosion of more equipment by oxalic acid circulating in the system, realizes slow shutdown of the system, and ensures the service life of the catalyst, but also avoids the influence of steam on pH detection, thereby improving the accuracy of pH detection results.

[0036] The above is only an embodiment of the utility model, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the utility model, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the utility model. The specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A waterway monitoring device for a natural gas to ethylene glycol reactor, comprising a steam drum and a reactor, wherein the bottom outlet of the steam drum is connected to the shell side inlet of the reactor, the shell side outlet of the reactor is connected to a return pipe, and the end of the return pipe away from the reactor is connected to the steam drum, characterized in that: It also includes a pH detector I, a pH detector II, a cooler, a circulating water neutralization tank, an alkali solution replenishing pipe, a preheater and a deaerator. The pH detector I is used to detect the pH value of the water in the return water pipe, and the pH detector II is used to detect the pH value of the water in the circulating water neutralization tank; a regulating valve I is installed on the return water pipe, a circulating water neutralization pipe is connected to the return water pipe, a regulating valve II is installed on the circulating water neutralization pipe, one end of the circulating water neutralization pipe away from the return water pipe is connected to the inlet of the cooler, the outlets of the alkali solution replenishing pipe and the cooler are both connected to the circulating water neutralization tank, the outlet of the circulating water neutralization tank is connected to the inlet of the preheater, the outlet of the preheater is connected to the inlet of the deaerator, the outlet of the deaerator is connected to the boiler feed water pipeline of the steam drum, a water pump II is installed on the pipeline between the circulating water neutralization tank and the preheater, a regulating valve III is installed on the alkali solution replenishing pipe, and a valve I is installed on the pipeline between the deaerator and the boiler feed water pipeline of the steam drum.

2. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 1, characterized in that: The return water pipe is connected to a circulating water detection pipe, a cooling sleeve is arranged outside the circulating water detection pipe, and a pH value detector I is installed on the circulating water detection pipe; the end of the circulating water detection pipe away from the return water pipe is connected to branch pipe I and branch pipe II, and regulating valve IV is installed on branch pipe I and branch pipe II; valve II is installed on the pipeline between the circulating water neutralization tank and the preheater, the end of branch pipe I away from the circulating water detection pipe is connected to the pipeline between valve II and the preheater, and the end of branch pipe II away from the circulating water detection pipe is connected to the circulating water neutralization tank.

3. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 1 or 2, characterized in that: A reverse osmosis water purifier is arranged between the circulating water neutralization tank and the preheater, and the water in the circulating water neutralization tank flows into the preheater after being purified by the reverse osmosis water purifier.

4. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 2, characterized in that: It also includes a controller, and pH detector I, pH detector II, regulating valve I, regulating valve II, regulating valve III, regulating valve IV and water pump II are all electrically connected to the controller. The controller controls the opening and closing of regulating valve I, regulating valve II and regulating valve IV according to the signal transmitted from pH detector I. The controller controls the opening of regulating valve III and the operation of water pump II according to the signal transmitted from pH detector II.

5. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 4, characterized in that: A regulating valve V is installed on the pipeline between the circulating water neutralization tank and the preheater. The regulating valve V is electrically connected to the controller. The controller controls the opening and closing of the regulating valve V according to the signal transmitted from the pH detector II.

6. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 1 or 5, characterized in that: A stirrer for stirring is arranged in the circulating water neutralization tank.

7. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 1, characterized in that: The steam outlet of the steam drum is connected with a by-product steam pipe, and a regulating valve VI is installed on the by-product steam pipe.

8. The waterway monitoring device for a natural gas to ethylene glycol reactor according to claim 1, characterized in that: A regulating valve VII is installed on the boiler feed water pipeline of the steam drum.

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