CN205295238U - Heavy hydrocarbon , heavy oil and heavy -oxygen -enriched water's separator among MTO process - Google Patents

Abstract

The utility model discloses a separation device for heavy hydrocarbons, heavy oil and oxygen-enriched water in the MTO process, which comprises a buffer tank at the inlet of the product gas compressor section, a heavy hydrocarbon flash tank and an oil-water separator; wherein the inlet of the product gas compressor section is The bottom discharge port of the buffer tank is connected with the feed port of the heavy hydrocarbon flash tank, and the flash liquid discharge port at the bottom of the heavy hydrocarbon flash tank is connected with the feed port of the oil-water separator; the top of the heavy hydrocarbon flash tank The gas phase discharge port of the first section of the compressor is connected to the product gas inlet of the first-stage inlet buffer tank; the oil-water separator is respectively provided with an oil phase discharge port and a water phase discharge port, and the oil phase discharge port is connected with the C6 product storage tank, and the water phase The phase outlet is connected with the oxide stripping tower. The device realizes the recovery and utilization of heavy hydrocarbons, heavy oils and oxides in the MTO process, which can save resources and reduce production costs. At the same time, it can also avoid the accumulation of heavy hydrocarbons and oxides in the system and prevent the blockage of the quench tower.

Description

Separation device for heavy hydrocarbon, heavy oil and oxygen-enriched water in MTO process

technical field

The utility model relates to chemical equipment, in particular to a separation device for heavy hydrocarbon, heavy oil and oxygen-enriched water in the MTO process.

Background technique

At present, in the methanol-to-olefins (MTO) process, the oxygen-enriched water containing heavy hydrocarbons at the bottom of the buffer tank at the first stage of the product gas compressor and the oxygen-enriched water at the top of the separation tower containing polymethylbenzene oils are directly oxidized. Under the current process conditions, it is difficult for heavy oil to be effectively treated through the stripper, resulting in a large amount of oil in the stripping water at the bottom of the oxide stripper, and the oil will continue to grow over time. Continuously accumulating in the system, the water quality of the oxide stripping tower continues to deteriorate, which directly affects the stable operation of the oxide absorption tower and the quench tower as downstream stripping water users, and then affects the long-term operation of the entire MTO unit.

Contents of the invention

The purpose of the utility model is to provide a separation device for heavy hydrocarbon, heavy oil and oxygen-enriched water in the MTO process. The device changes the process flow, adds a heavy oil flash tank to recover some heavy hydrocarbons, and adds an oil-water separation system to recover oily substances, which is conducive to improving the water quality of the oxide stripper and avoiding the long-term accumulation and circulation of heavy hydrocarbons and oxides in the system , which is conducive to the long-term stable operation of the MTO device.

The purpose of this utility model is achieved by the following measures:

A separation device for heavy hydrocarbons, heavy oil and oxygen-enriched water in the MTO process, including a buffer tank at the inlet of a product gas compressor, characterized in that the separation device also includes a heavy hydrocarbon flash tank and an oil-water separator; wherein The bottom outlet of the buffer tank at the inlet of the product gas compressor is connected to the feed port of the heavy hydrocarbon flash tank through the buffer tank discharge pump, and the flash liquid outlet at the bottom of the heavy hydrocarbon flash tank is passed through the heavy hydrocarbon flash tank. The discharge pump of the steamer is connected with the feed port of the oil-water separator;

The gas phase discharge port on the top of the heavy hydrocarbon flash tank is connected to the product gas inlet of the buffer tank at the first section of the compressor through a return pipeline; the oil-water separator is respectively provided with an oil phase discharge port and a water phase discharge port, and the oil phase The discharge port is connected with the C6 product storage tank, and the water phase discharge port is connected with the oxide stripping tower.

The gas phase discharge port at the top of the oil-water separator is connected to the product gas inlet of the first-stage inlet buffer tank of the compressor through a pipeline.

The inlet buffer tank of the first section of the compressor is equipped with a remote liquid level gauge, and a liquid level control valve for the inlet buffer tank is installed behind the discharge pump of the buffer tank.

The heavy hydrocarbon flash tank is provided with a remote liquid level gauge, and the heavy hydrocarbon flash tank discharge pump is provided with a liquid level control valve for the heavy hydrocarbon flash tank.

A reboiler is also provided at the bottom of the heavy hydrocarbon flash tank.

A water-cooled heat exchanger is also arranged on the connecting pipeline between the discharge pump of the heavy hydrocarbon flash tank and the feed port of the oil-water separator; The parallel pipeline branch is used to combine the water in the upper part of the separation tower into the oil-water separator.

The oxygen-enriched water containing heavy hydrocarbons in the inlet buffer tank of the MTO product gas compressor enters the heavy oil flash tank through the buffer tank outlet pump under liquid level control, and is heated by low-pressure steam (LLPS) to partially vaporize and flash out The light components of the gas phase are returned to the inlet buffer tank of the product gas compressor for recovery. The liquid phase is pressurized by the discharge pump of the heavy oil flash tank, cooled by a water-cooled heat exchanger, and then enters the oil-water separation tank. After oil-water separation, the oil product is sent to the C6 product storage tank together with the C6 product of the OCP unit under liquid level control. The water phase containing oxides is sent to the oxide stripping tower under interface control for oxide recovery, and the light components in the gas phase in the oil-water separation tank are returned to the first-stage inlet buffer tank of the product gas compressor through the top gas outlet pipeline for recovery.

Beneficial effect:

The utility model can realize the recovery and utilization of heavy hydrocarbons, heavy oils and oxides in the MTO process, can save resources and reduce production costs. The separate treatment of heavy hydrocarbons and oxygen-enriched water produced by the MTO process can also avoid the accumulation of heavy hydrocarbons and oxides in the system, prevent the blockage of the quench tower, and help improve the absorption effect of the oxide absorption tower.

Description of drawings

Fig. 1 is a structural schematic diagram of a separation device for heavy hydrocarbons, heavy oil and oxygen-enriched water in an MTO process of the present invention. Among them, 1 is the inlet buffer tank of the product gas compressor section, 2 is the discharge pump of the buffer tank, 3 is the liquid level control valve, 4 is the heavy hydrocarbon flash tank, 5 is the reboiler, 6 is the flow control device, and 7 is the flow rate Control device, 8 is the heavy hydrocarbon flash tank discharge pump, 9 is the liquid level control valve, 10 is the water-cooled heat exchanger, 11 is the oil-water separator, 13 is the pressure control device, 14 is the C6 product storage tank, 15 is The oxide stripping tower, 16 is a separation tower.

detailed description

A separation device for heavy hydrocarbons, heavy oil and oxygen-enriched water in the MTO process, including a buffer tank 1 at the inlet of the product gas compressor section, a heavy hydrocarbon flash tank 4, and an oil-water separator 11; wherein the buffer tank at the inlet of the product gas compressor section The bottom discharge port of 1 is connected with the feed port of the heavy hydrocarbon flash tank 4 through the buffer tank discharge pump 2, and a remote liquid level gauge LIC is also set on the product gas compressor section inlet buffer tank 1, which will control The signal is transmitted to the liquid level control valve 3 behind the buffer tank discharge pump 2 to control the liquid level in the buffer tank 1 at the inlet of the first section of the compressor; the flash liquid outlet at the bottom of the heavy hydrocarbon flash tank 4 passes through the heavy hydrocarbon The flash tank discharge pump 8 is connected to the feed port of the oil-water separator 11; a remote liquid level gauge LIC is also set on the heavy hydrocarbon flash tank 4, and the control signal is transmitted to the heavy hydrocarbon flash tank discharge The liquid level control valve 9 of the heavy hydrocarbon flash tank 4 arranged after the pump 8 . The top of the heavy hydrocarbon flash tank 4 is provided with a gas return pipeline for returning the gas phase components in the heavy hydrocarbon flash tank 4 to the product gas compressor section inlet buffer tank 1, and the gas return pipeline is connected with the oil-water separator 11 The gas outlet pipeline provided at the top merges into the inlet pipeline of the separation tower product gas and then merges into the first section of the inlet buffer tank 1 of the product gas compressor; a pressure control device 13 is also arranged on the top gas outlet pipeline of the oil-water separator 11, so that The oil-water separator is respectively provided with an oil phase outlet and a water phase outlet, the oil phase outlet is connected to the C6 product storage tank 14, and the water phase outlet is connected to the oxide stripper 15. The heavy hydrocarbon flash tank 4 is also provided with a reboiler 5, the reboiler 5 has a low-pressure steam inlet and a low-pressure condensate outlet, and the low-pressure condensate flow is controlled by a flow control device 6 . A water-cooled heat exchanger 10 is also arranged on the connecting pipeline between the discharge pump 8 of the heavy hydrocarbon flash tank and the feed port of the oil-water separator 11, and a parallel pipeline branch is set before the water-cooled heat exchanger 10. The pipeline is used to combine the water in the upper part of the separation tower 16 into the oil-water separator 11, and a flow control device 7 is arranged on the pipeline branch; the water-cooled heat exchanger 10 is provided with a circulating water return pipeline and a circulating water upper water pipeline .

When the separation device for heavy hydrocarbons, heavy oil and oxygen-enriched water in the MTO process described in the utility model is working, the product gas from the separation tower is compressed in the four-stage centrifugal type with an inter-stage cooler and an inter-stage buffer tank. The compressor is compressed step by step from 250kpa to about 3000kpa, and the interstage fluid of the compressor is cooled and flashed in the interstage cooler and interstage buffer tank respectively, thereby removing most of the water and heavy hydrocarbons. The inter-stage condensate, including water and some liquid hydrocarbons, is sent back to the first-stage inlet buffer tank 1 of the product gas compressor after passing through the inter-stage buffer tank, and the oxygen-enriched water containing heavy hydrocarbons in the liquid Under position control, the heavy oil enters the heavy oil flash tank 4 through the discharge pump 2 of the buffer tank, and is partially vaporized by heating with low-pressure steam (LLPS), and the low-pressure condensate is controlled by the flow control device 6 . The gas phase light components flashed out are returned to the buffer tank 1 at the inlet of the first section of the product gas compressor for recovery. The liquid phase is pressurized by the discharge pump 8 of the heavy oil flash tank, and then enters the oil-water separation tank 11 after being cooled by the water-cooled heat exchanger 10 under the control of the liquid level control valve 9 of the heavy hydrocarbon flash tank. After oil-water separation, the oil product is sent to the C6 product storage tank 14 together with the C6 product of the OCP unit under liquid level control. The water phase containing oxides is sent to the oxide stripping tower 15 under interface control to recover oxides, and the light components in the gas phase in the oil-water separation tank 11 are returned to the buffer tank 1 at the inlet of the first stage of the product gas compressor through the top outlet pipeline. Recycle.

Claims (7)

1. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a MTO technical process, including one section of inlet buffer (1) of gas product compressor, it is characterized in that, described segregation apparatus also includes heavy hydrocarbon flash tank (4) and oil water separator (11); Wherein the bottom discharge mouth of one section of inlet buffer (1) of gas product compressor is connected with the charging aperture of heavy hydrocarbon flash tank (4), and the flash liquid discharging opening of described heavy hydrocarbon flash tank (4) bottom is connected with the charging aperture of oil water separator (11);

The gas phase discharging opening at described heavy hydrocarbon flash tank (4) top is connected to the gas product import of one section of inlet buffer (1) of compressor by reflux line; Described oil water separator (11) is respectively provided with oil phase discharging opening and aqueous phase discharging opening, and oil phase discharging opening is connected with C6 product storage tank (14), and aqueous phase discharging opening is connected with oxide stripper (15).

2. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 1, it is characterized in that, the gas phase discharging opening at described oil water separator (11) top is connected to the gas product import of one section of inlet buffer (1) of compressor by pipeline.

3. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 1, it is characterised in that described heavy hydrocarbon flash tank (4) bottom is additionally provided with reboiler (5).

4. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 1, it is characterized in that, the connection pipeline between described heavy hydrocarbon flash tank discharging pump (8) and the charging aperture of oil water separator (11) is additionally provided with water-cooled heat exchanger (10).

5. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 4, it is characterized in that, on described connection pipeline, water-cooled heat exchanger (10) front arrange a parallel pipeline branch road for by knockout tower (16) upper water interflow in oil water separator (11).

6. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 1, it is characterized in that, one section of inlet buffer (1) of described compressor arranges far transmission level meter, after surge tank discharging pump (2), is provided with the fluid level control valve (3) of inlet buffer (1).

7. the segregation apparatus of heavy hydrocarbon, heavy oil and heavy-oxygen-enriched water in a kind of MTO technical process according to claim 1, it is characterized in that, described heavy hydrocarbon flash tank (4) arranges far transmission level meter, after heavy hydrocarbon flash tank discharging pump (8), is provided with the fluid level control valve (9) of heavy hydrocarbon flash tank (4).