Novel operation method of process condensate stripping tower

Abstract

The invention discloses a novel operation method of a process condensate stripping tower, which specifically comprises the following steps: opening a first gate valve and a second gate valve, and establishing a process condensate heat exchanger tube pass and a process condensate stripping tower liquid level to 20-30% by using desalted water; opening a gate valve, a fourth gate valve and a sixth gate valve, establishing a process condensate heat exchanger tube stroke and a process condensate stripping tower liquid level to 50%-60% by using desalted water, opening a seventh gate valve, introducing superheated steam into the process condensate stripping tower for tower heating, temperature rising and pressure rising, introducing superheated steam into the process condensate stripping tower for tower heating, temperature rising and pressure rising, and then introducing superheated steam into the process condensate stripping tower for tower heating, temperature rising and pressure rising; after the low-change gas-water separator contains the process condensate, the process condensate pump is started to input the condensate into the process condensate stripping tower. The process pipeline and operation are improved, the start-up time of the process condensate stripping tower is shortened, discharge of unqualified process condensate is completely eradicated, and water pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of thin-walled parts processing, in particular to a novel operating method of a process condensate stripping tower. Background Art

[0002] The current low-gas classifier of the synthetic ammonia unit separates a large amount of impurities in the process condensate. In addition to dissolved CO2 (3000mg / L), it also contains ammonia (1000mg / L), methanol (20mg / L), formaldehyde (5mg / L), methylamine (5mg / L), etc. generated by high-low-gas side reactions. Methanol is toxic, methylamine is neutral, and formic acid and formaldehyde are reducing agents. The discharge of this part of the condensate to the ground will cause excessive ammonia nitrogen in the external drainage and pollute the water body. Superheated steam should be used for stripping treatment to remove the trace ammonia, formaldehyde, methylamine, carbon dioxide and alcohol gas dissolved in the process condensate, and enter the process steam for reuse. The conductivity of the water at the outlet of the stripping tower is ≤10μs / cm. The qualified process condensate is sent to the desalted water station after heat recovery and mixed with semi-desalted water, and enters the mixed bed for further treatment into desalted water for use in high and medium pressure boilers; it is beneficial in terms of comprehensive utilization and elimination of three wastes.

[0003] In normal production, the total amount of process condensate is about 25,000 kg / hr, which is sent to the 01E0103 series heat exchanger by the process condensate pump 01P0304 through the liquid level control valve LV-304B. The liquid level control valve LV-304B and its split pair LV-304A are closed when the air source fails. Both valves are equipped with hand wheels. If the process condensate pump jumps or LV-304B is closed, the liquid level control valve LV-304A will open and discharge the process condensate to the return ditch.

[0004] The process condensate at a temperature of about 80°C delivered by pump 01P0304 is preheated by the process condensate after gas stripping on the shell side in the process condensate heat exchanger 01E0103 tube pass to a temperature of 220°C, as measured by the local temperature gauge TI-101, and then the condensate is evenly distributed through a tower top distributor. The process condensate stripping tower 01T0101 has two beds, each with a liquid distribution tray. Each bed is filled with stainless steel rings, which are supported on a stainless steel gas injection plate at the bottom of the bed. The stainless steel ring packing is held in place by a fixed grid. A 15mm high wire mesh demister is provided at the top of the tower to remove droplets entrained by medium-pressure steam. After the stripping gas leaves the tower, it is combined with the process steam through the gas stripping steam flow control valve FV-109 and sent to the 01B0101 feed system. The bottom liquid outlet of 01T0101 is equipped with a vortex preventer. The bottom liquid level of 01T0101 is regulated by controlling the valve LV-101 on the shell outlet pipeline of heat exchanger 01E0103 to adjust the liquid level of the gas stripping tower. Valve LV-101 is closed for gas source failure and is equipped with a hand wheel for maintenance and manual operation.

[0005] The 25000kg / hr stripping condensate at the outlet of the stripping tower at about 250℃ is indicated by TIA-101 on the DCS and provides a low temperature alarm. After leaving the tower, the condensate is cooled to about 110℃ in the shell of the process condensate heat exchanger 01E0103, enters the process condensate water cooler 01E0104 to exchange heat with circulating water, and further cools the temperature to 40℃ before being sent to the boundary desalted water terminal. The conductivity is monitored and recorded by the online analyzer AR-104. When the conductivity exceeds the standard, an over-standard alarm will be issued, the high conductivity interlock solenoid valve XY-104A will be opened, the valve XV-104A will be opened to discharge the over-standard stripping condensate to the sewer, and the valve XV-104B will be closed to cut off the condensate going to the desalted water terminal.

[0006] The current process condensate stripping tower start-up operation is as follows:

[0007] (1) Construction of process condensate stripping tower:

[0008] Start a process condensate pump according to the regulations, slowly turn down LV-304A, open LIC-304B to add liquid to the process condensate stripping tower T0101 to 50%~60%. Open the stop valves before and after LIC-101 during inspection, and open the root valve before XV-104A. The master control opens LIC-101 to control the liquid level of the process condensate stripping tower at 50%~60%, manually open XV-104A, and the water is discharged at XV-104A. Adjust LIC-304A to control the liquid level of the low-temperature gas-water separator.

[0009] (2) Process condensate stripping tower warming tower:

[0010] Lead the steam to the process condensate stripping tower, drain it along the way until it is qualified, and then close it. Open the top of the process condensate stripping tower to vent, open the small bypass valve for steam inlet, and slowly send steam in to warm the tower.

[0011] (3) Boosting the pressure of the process condensate stripping tower: After warming up the tower for a period of time, slowly open the main steam valve entering the tower, close the auxiliary valve, and gradually close the tower top vent valve to boost the pressure of the process condensate stripping tower. The boosting rate is 0.4Mpa / h.

[0012] (4) When the process condensate temperature TI-161 at the outlet of the process condensate stripping tower reaches about 200℃, close the tower top to vent. When the pressure of the process condensate stripping tower is raised to the same as the steam pressure entering the first stage furnace, open the FIC-109 root valve during inspection, and the master control slowly opens FIC-109 to send steam to the first stage furnace. And timely track and adjust FIC-105 to control the water-carbon ratio of the first stage furnace.

[0013] (5) After the system is stable, close LIC-304A and slowly send all the process condensate into the process condensate stripping tower. Use LIC-304B to control the liquid level of the low-temperature gas-water separator.

[0014] (6) Put online analysis into use and adjust the steam volume of FIC-109. After the water quality is qualified (conductivity <10us / cm), the root valve of XV-104B is opened for inspection, and the master control closes XV-104A and opens XV-104B. The qualified process condensate is sent to the desalted water station.

[0015] The device is easy to operate. When starting up, add process condensate to the stripping tower to establish a normal liquid level, then introduce a small amount of medium-pressure steam, and increase the pressure of the stripping tower PI-104 to 2.5MPa at a pressure increase rate of 0.5-0.8MPa / h. After the process condensate temperature TI-161 at the stripping tower outlet reaches about 200°C, the medium-pressure saturated steam can be incorporated into the process steam system. After the conductivity of the condensate out of the tower is qualified (≤10μS / cm), it can be used as conversion jacket water or sent to the desalted water station. During the entire process, the condensate stripping tower is heated, heated and pressurized, and it takes 3-4 hours to start up. During this period, unqualified condensate needs to be sent to the sewage treatment station, increasing the cost of sewage treatment.

[0016] Therefore, we propose a novel operation method for the process condensate stripping column. Summary of the invention

[0017] The object of the present invention is to provide a novel operation method of a process condensate stripping tower, which solves the problems raised in the background technology.

[0018] To achieve the above object, the present invention provides the following technical solution: a novel operation method of a process condensate stripping tower, comprising the following method steps:

[0019] Step 1: 4 to 5 hours before the 01S0301A low-temperature steam-water separator produces process condensate, open the valve on the pipeline connecting a ￠10 0Cr 18Ni9 pipeline from the desalted water main pipe to the 01E0103 process condensate heat exchanger's shower double valve until the process condensate stripping tower liquid level reaches 20% to 30%, close the desalted water valve, and ensure that the process condensate heat exchanger is filled with desalted water;

[0020] Step 2: Open the desalted water main pipe and connect a ￠10 0Cr 18Ni9 pipeline to the valve on the pipeline of the double valve between the process condensate pump 01P0304 and the process condensate heat exchanger 01E0103. The desalted water enters the process condensate stripping tower through the process condensate heat exchanger. When the liquid level of the process condensate stripping tower reaches 50% to 60%, close the desalted water valve to ensure that the process condensate heat exchanger is full of desalted water and the liquid level of the process condensate stripping tower is 50% to 60%.

[0021] Step 3: Open the seventh gate valve to introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure;

[0022] Step 4: Introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure;

[0023] Step 5: After there is process condensate in the low-temperature gas-water separator, start the process condensate pump to input condensate into the process condensate stripping tower.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. After ensuring that there is process condensate in the low-temperature gas-water separator, the process condensate pump can be directly started to send the condensate to the process condensate stripping tower, and the condensate leaving the process condensate stripping tower is qualified.

[0026] 2. Eliminate the discharge of unqualified process condensate and reduce environmental pollution.

[0027] 3. Reduce the amount of condensate that does not meet the process requirements and send it to the sewage treatment plant, thereby reducing the cost of sewage treatment.

[0028] 4. Make the operation safer and more reliable, and ensure that the process condensate heat exchanger is not damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 The present invention is a flow chart of a novel operation method of a process condensate stripping tower.

[0031] In the figure:

[0032] 1-01S0301A Low-temperature gas-water separator is used to separate the process condensate in low-temperature gas.

[0033] 2-01P0304 process condensate pump is used to pressurize the process condensate and send it to the process condensate stripping tower.

[0034] 3-01E0103 process condensate heat exchanger is used to exchange heat between process condensate at 80℃ on the tube side and 200℃ on the shell side, thereby increasing the inlet temperature of process condensate to the tower.

[0035] 4-01T0101 process condensate stripping tower is used to make countercurrent contact between superheated steam and process condensate, conduct mass transfer and heat conversion in the packing layer, and strip out CO2, ammonia, methanol, formaldehyde, methylamine, etc. in the process condensate to produce qualified process condensate.

[0036] 5-01E0104 process condensate water cooler is used to cool the process condensate at 80℃ to 40℃.

[0037] 6-The first gate valve is used to control the amount of desalted water added to the process condensate heat exchanger (tube side).

[0038] 7-the second gate valve and 8-the third gate valve are used to discharge the condensate from the process condensate heat exchanger (tube side).

[0039] 9-The fourth gate valve is used to control the amount of desalted water added to the process condensate heat exchanger (shell side).

[0040] 10-the fifth gate valve and 11-the sixth gate valve are used to discharge the condensate from the process condensate heat exchanger (shell side).

[0041] 12-The seventh gate valve is used to control the amount of superheated steam added to the process condensate stripping tower. DETAILED DESCRIPTION

[0042] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0043] Example

[0044] See also Figure 1 , a novel method for operating a process condensate stripping tower, comprising the following equipment:

[0045] It includes sequentially connected 1-01S0301A low-transformation gas-water separator, 2-01P0304 process condensate pump, 3-01E0103 process condensate heat exchanger, 4-01T0101 process condensate stripping tower, 5-01E0104 process condensate water cooler, 6-first gate valve, 7-second gate valve, 8-third gate valve, 9-fourth gate valve, 10-fifth gate valve, 11-sixth gate valve, 12-seventh gate valve;

[0046] in:

[0047] The outlet of 01S0301A low-temperature gas-water separator 1 is connected to 01P0304 process condensate pump 2;

[0048] 01P0304 process condensate pump 2 is connected to 01E0103 process condensate heat exchanger tube 3;

[0049] 01E0103 process condensate heat exchanger tube 3 is connected to 01T0101 process condensate stripping tower 4;

[0050] The process condensate stripping tower 4 is connected to the shell side 3 of the 01E0103 process condensate heat exchanger;

[0051] 01E0103 process condensate heat exchanger shell side 3 is connected to 01E0104 process condensate water cooler 5;

[0052] The first gate valve 6 pipeline is connected to the pipeline between the second gate valve 7 and the third gate valve 8;

[0053] The pipeline of the fourth gate valve 9 is connected to the pipeline between the fifth gate valve 10 and the sixth gate valve 11;

[0054] The seventh gate valve 12 pipeline is connected to the 01T0101 process condensate stripping tower 4.

[0055] The specific operations are as follows:

[0056] 1. 4 to 5 hours before the 01S0301A low-temperature steam-water separator produces process condensate, open the valve on the pipeline from the desalted water main pipe to the double valve of the 01E0103 process condensate heat exchanger until the liquid level of the process condensate stripping tower reaches 20% to 30%, then close the desalted water valve to ensure that the process condensate heat exchanger is filled with desalted water.

[0057] 2. Open the desalted water main pipe and connect a ￠10 0Cr 18Ni9 pipeline to the valve on the pipeline of the double valve between the process condensate pump 01P0304 and the process condensate heat exchanger 01E0103. The desalted water enters the process condensate stripping tower through the process condensate heat exchanger. When the liquid level of the process condensate stripping tower reaches 50% to 60%, close the desalted water valve to ensure that the process condensate heat exchanger is full of desalted water and the liquid level of the process condensate stripping tower is at 50% to 60%.

[0058] 3. Open the seventh gate valve to introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure.

[0059] 4. Introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure.

[0060] 5. After there is process condensate in the low-temperature gas-water separator, start the process condensate pump to input condensate into the process condensate stripping tower.

[0061] In summary, the start-up of the process condensate stripping tower must have a certain liquid level at the bottom of the stripping tower to play the role of liquid seal before adding superheated steam to warm the tower and increase the temperature and pressure. If there is no liquid seal, after the steam is passed, the steam will enter the process condensate heat exchanger (shell side), causing the heat exchanger to be heated on one side, the process condensate heat exchanger to deform, the tube sheet to crack, and the heat exchanger to be damaged. The present invention is to add desalted water to the process condensate stripping tower 4 to 5 hours before the low-transformation separator produces process condensate, establish the process condensate stripping tower liquid level at 50% to 60%, play the role of liquid seal, and then pass steam to the steam tower to warm the tower. After the temperature and pressure are qualified, after the low-transformation gas-water separator has process condensate, the process condensate pump can be directly started to send the condensate to the process condensate stripping tower, and the qualified condensate after stripping is sent to the desalted water station. This method prevents the discharge of unqualified process condensate and reduces water pollution.

[0062] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0063] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A novel method for operating a process condensate stripping tower, characterized in that: The method comprises the following steps: Step 1: 4 to 5 hours before the 01S0301A low-temperature steam-water separator produces process condensate, open the valve on the pipeline connecting a ￠10 0Cr 18Ni9 pipeline from the desalted water main pipe to the 01E0103 process condensate heat exchanger's shower double valve until the process condensate stripping tower liquid level reaches 20% to 30%, close the desalted water valve, and ensure that the process condensate heat exchanger is filled with desalted water; Step 2: Open the desalted water main pipe and connect a ￠10 0Cr 18Ni9 pipeline to the valve on the pipeline of the double valve between the process condensate pump 01P0304 and the process condensate heat exchanger 01E0103. The desalted water enters the process condensate stripping tower through the process condensate heat exchanger. When the liquid level of the process condensate stripping tower reaches 50% to 60%, close the desalted water valve to ensure that the process condensate heat exchanger is full of desalted water and the liquid level of the process condensate stripping tower is 50% to 60%. Step 3: Open the seventh gate valve to introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure; Step 4: Introduce superheated steam into the process condensate stripping tower to warm the tower and increase the temperature and pressure; Step 5: After there is process condensate in the low-temperature gas-water separator, start the process condensate pump to input condensate into the process condensate stripping tower.

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