Drainage device for torch system of methanol-to-olefin device

Abstract

The utility model discloses a drainage device for a torch system of a methanol-to-olefin device, which comprises a torch and vent gas entering the torch for combustion through a liquid separation tank and a water-sealed tank, and is characterized by further comprising a condensate pump and a waste water collecting tank, a condensate outlet at the bottom of the liquid separation tank is connected with a condensate discharge pipe, and a condensate outlet at the bottom of the water-sealed tank is connected with a waste water collecting tank. A condensate outlet at the bottom of the water-sealed tank is connected with a condensate discharge pipe, and the condensate discharge pipe is provided with a condensate pump and is connected to a wastewater collection tank; wastewater in the wastewater collecting tank is conveyed to the boiler for incineration, and gas-phase materials on the top of the tank are conveyed to the ultralow-emission combustion device for incineration. The device provided by the utility model can keep the liquid levels of the water-sealed tank and the liquid separation tank stable when the MTO device is started / stopped and under abnormal conditions, and ensures the safe operation of a torch facility.

Description

Technical Field

[0001] This utility model relates to a methanol-to-olefins (MTO) plant, specifically to a flare system drainage device for a methanol-to-olefins plant, which controls the stability of flare system drainage during start-up and shutdown. Background Technology

[0002] In a methanol-to-olefins (MTO) unit, a flare system is installed as a supporting safety facility, consisting of one high-pressure flare system and one low-pressure flare system. The high-pressure flare system handles emissions from the butanol and octanol units, the MTO unit, and the tank farm under emergency conditions, while the low-pressure flare system handles emissions from the butanol and octanol tank farm. The flare system ensures that vented air generated during start-up, shutdown, normal operation, and emergency situations can be vented and combusted in a timely, safe, and reliable manner. After entering the flare unit through the pipe gallery, the vented air enters the high-pressure separator for separation. The separated vented air then enters the water seal tank, where a water seal of a certain height isolates the flare system from the upstream units, ensuring the safety of the upstream units.

[0003] The MTO unit experiences significant system fluctuations during start-up and shutdown. The composition of the vented air at the front end is complex, and the vented air emission volume fluctuates greatly. During the emission process, condensate forms in the flare separator, while gaseous materials burn at the top of the flare. Liquid materials condense in the flare separator and water seal tank. When the liquid levels in these tanks are high, they are manually discharged by gravity through pipelines to the flare wastewater tank. Large fluctuations in the liquid levels in the flare separator and water seal tank cause significant vibration in the flare pipelines, which can severely impact the safe operation of the flare. Furthermore, the waste liquid contains organic matter, and the condensate discharged into the flare wastewater tank has a strong, difficult-to-eliminate odor, posing safety and environmental risks. Summary of the Invention

[0004] The purpose of this invention is to provide a drainage device for the flare system of a methanol-to-olefins (MTO) unit, which can solve the problem caused by fluctuations in the amount of vented air during the start-up / shutdown of the MTO unit, maintain stable liquid levels in the flare water seal tank and separator tank during start-up / shutdown, ensure normal operation of the flare facilities, and at the same time treat waste liquid pollution and eliminate odors from the flare system.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A flare system drainage device for a methanol-to-olefins (MTO) plant includes a flare, through which vented air enters the flare for combustion via a separator and a water seal tank. The device further includes a condensate pump and a wastewater collection tank. The condensate outlet at the bottom of the separator is connected to a condensate discharge pipe, and the condensate outlet at the bottom of the water seal tank is also connected to the condensate discharge pipe. The condensate discharge pipe is equipped with a condensate pump and connected to the wastewater collection tank. Wastewater in the wastewater collection tank is sent to a boiler for incineration, and gaseous material at the top of the tank is sent to an ultra-low emission combustion device (CEB) for incineration.

[0007] Furthermore, the separator is equipped with baffles and wire mesh to improve the liquid removal effect.

[0008] Furthermore, the condensate pump is a metering pump, which can control the outlet flow rate of the condensate pump, thereby controlling the liquid level in the separator.

[0009] Furthermore, bypass pipelines are added to the inlet and outlet of the condensate pump, which can be used to purge and collect the material inside the pipeline.

[0010] Furthermore, a check valve is installed at the outlet of the condensate pump on the condensate discharge pipe.

[0011] Furthermore, the device includes a flare wastewater tank, a condensate outlet at the bottom of the separator is connected to the flare wastewater tank, and a condensate outlet at the bottom of the water seal tank is connected to the flare wastewater tank.

[0012] Beneficial Effects: This utility model's methanol-to-olefins (MTO) flare system drainage device ensures stable liquid levels in the flare water seal tank and separator tank during MTO unit start-up / shutdown, normal operation of the flare facility, and environmental control of odors around the flare. The device discharges waste liquid from the flare separator tank and water seal tank to a newly added wastewater collection tank via a condensate pump. When high liquid levels in the flare separator tank and water seal tank require discharge, a new discharge process is implemented, pumping condensate to the wastewater collection tank. The waste liquid in the collection tank is then sent to the boiler for incineration, while the vapor phase at the top of the collection tank is collected and sent to an ultra-low emission combustion device for incineration. This device ensures stable liquid levels in the water seal tank and separator tank during MTO unit start-up / shutdown and in abnormal situations, guaranteeing safe operation of the flare facility. Effective collection of flare condensate results in no odor at the flare site, achieving environmental compliance. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the drainage device of the flare system in the methanol-to-olefins unit of this utility model.

[0014] Among them, 1 is the separator, 2 is the water seal tank, 3 is the flare head, 4 is the flare wastewater pool, 5 is the condensate pump, 6 is the wastewater collection tank, 7 is the check valve, 8 is the separator drain valve, 9 is the water seal tank drain valve, 10 is the condensate drain valve, 11 is the condensate pump bypass valve, 12 is the separator bottom valve, 13 is the water seal tank inner cylinder bottom valve, 14 is the water seal tank outer cylinder bottom valve, 15 is the water seal tank inner and outer cylinder connecting valve, and 16 is the separator water seal tank connecting valve. Detailed Implementation

[0015] The technical solution of this utility model will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of this utility model.

[0016] like Figure 1 The methanol-to-olefins (MTO) unit flare system drainage device includes the in-use flare 3, separator 1, water seal tank 2, and flare wastewater pool 4. Air is released through separator 1 and water seal tank 2 into the flare head 3 for combustion. Condensate generated during the discharge process flows naturally to the flare wastewater pool 4 under gravity. Water seal tank 2 isolates the flare system from upstream units through a water seal of a certain height, ensuring the safety of the upstream units. Water seal tank 2 is a level-controlled water seal tank, comprising inner and outer cylinders, each drained by a bottom valve. The device also includes a condensate pump 5 and a wastewater collection tank 8. The bottom valve 12 of the separator 1 is connected to the separator discharge valve 8, which is connected to the condensate discharge pipe. The bottom valve 13 of the inner cylinder and the bottom valve 14 of the outer cylinder of the water seal tank 2 are connected to the water seal tank discharge valve 9, which is connected to the condensate discharge pipe. The condensate discharge pipe is equipped with a condensate pump 5, which is connected to the wastewater collection tank 6 via a check valve 7 and the condensate discharge valve 10. The wastewater in the wastewater collection tank 6 is sent to the boiler for incineration, and the gaseous material on the top of the tank is sent to the ultra-low emission combustion device CEB for incineration.

[0017] The condensate pump 5 can be a metering pump, which can control the outlet flow rate of the condensate pump and ultimately control the liquid level of the separator 1, ensuring the stability of the liquid level of the separator 1.

[0018] In a preferred embodiment, a baffle and a wire mesh are provided inside the separator 1 to improve the liquid removal effect.

[0019] In a preferred embodiment, a bypass pipeline is added to the inlet and outlet of the condensate pump 5, and a condensate pump bypass valve 11 is installed on the bypass pipeline. Its function is to prevent the material in the pipeline from freezing in winter, and to purge and collect the material in the pipeline through this bypass pipeline, so as to keep the inlet and outlet pipelines of the condensate pump 5 free of material residue.

[0020] The drainage process of the flare system before and after adopting this utility model is as follows:

[0021] 1) When the liquid level of the original separator tank 1 is high and needs to be discharged, it is discharged to the flare wastewater pool 4 through the bottom valve 12 of the separator tank. When the liquid level of the water seal tank 2 is high and needs to be discharged, it is discharged to the flare wastewater pool 4 through the bottom valve 13 of the inner cylinder of the water seal tank, the bottom valve 14 of the outer cylinder of the water seal tank, and the connecting valve 15 of the inner and outer cylinders of the water seal tank.

[0022] 2) As shown in the figure, through the optimization of this utility model, the discharge of condensate from the separator 1 is achieved by adding a separator discharge valve 8, a condensate pump 5, and a wastewater collection tank 6. When the separator 1 is at a high liquid level and needs to be discharged, the separator water seal tank connecting valve 16 is closed, the separator bottom valve 12, the separator discharge valve 8, and the condensate discharge valve 10 are opened, the condensate pump 5 is started to discharge to the wastewater collection tank 6, and the stroke knob of the condensate pump 5 is adjusted to control the liquid level of the separator 1.

[0023] 3) As shown in the figure, the discharge of condensate from water seal tank 2 is achieved by adding water seal tank discharge valve 9. When water seal tank 2 is at a high liquid level and discharge is required, close the water seal tank connecting valve 16 of the separator tank and close the inner and outer cylinder connecting valve 15 of the water seal tank to keep the flow from water seal tank 1 to flare sewage tank 4 closed. Open the bottom valve 13 of the inner cylinder of the water seal tank, the water seal tank discharge valve 9, and the condensate discharge valve 10. Start the condensate pump 5 to discharge to the wastewater collection tank 6. Adjust the stroke of the condensate pump 5 to control the liquid level of water seal tank 2.

Claims

1. A drainage device for a flare system of a methanol-to-olefins unit, comprising a flare, wherein venting air enters the flare for combustion via a separatory tank and a water seal tank, characterized in that, The device also includes a condensate pump and a wastewater collection tank. The condensate outlet at the bottom of the separator is connected to a condensate discharge pipe, and the condensate outlet at the bottom of the water seal tank is connected to a condensate discharge pipe. A condensate pump is installed on the condensate discharge pipe and connected to the wastewater collection tank. The wastewater in the wastewater collection tank is sent to a boiler for incineration, and the gaseous material on the top of the tank is sent to an ultra-low emission combustion device for incineration.

2. The drainage device for the flare system of a methanol-to-olefins unit according to claim 1, characterized in that, The separator is equipped with baffles and wire mesh.

3. The drainage device for the flare system of a methanol-to-olefins unit according to claim 1, characterized in that, The condensate pump is a metering pump.

4. The drainage device for the flare system of a methanol-to-olefins unit according to claim 1, characterized in that, Bypass lines were added to the inlet and outlet of the condensate pump.

5. The drainage device for the flare system of a methanol-to-olefins unit according to claim 1, characterized in that, A check valve is installed at the outlet of the condensate pump on the condensate discharge pipe.

6. The drainage device for the flare system of a methanol-to-olefins unit according to claim 1, characterized in that, The device includes a flare wastewater tank, a condensate outlet at the bottom of a separatory tank connected to the flare wastewater tank, and a condensate outlet at the bottom of a water seal tank connected to the flare wastewater tank.

Images