Descaling device for methanol-to-olefin stripping water heat exchanger

Abstract

The utility model discloses a descaling device for a methanol-to-olefin stripping water heat exchanger, which comprises a stripping water heat exchanger and is characterized by further comprising a heavy fraction hydrocarbon buffer tank and a methanol ground tank, the heavy fraction hydrocarbon buffer tank is connected with a stripping water inlet of the stripping water heat exchanger through a pipeline, and the methanol ground tank is connected with the stripping water inlet of the stripping water heat exchanger through a pipeline. And a stripping water outlet of the stripping water heat exchanger is connected with the methanol ground tank through a pipeline. According to the descaling device for the methanol-to-olefin stripping water heat exchanger, the byproduct heavy fraction hydrocarbon of an MTO device is conveyed to the stripping water heat exchanger, is cleaned and then is discharged to a methanol ground tank, and the heavy fraction hydrocarbon is used for dissolving scales in the stripping water heat exchanger, so that the effects of improving the heat exchange efficiency of equipment and reducing the energy consumption of the device are achieved.

Description

Technical Field

[0001] This utility model belongs to the field of methanol-to-olefins (MTO) technology, specifically relating to a descaling device for a methanol-to-olefins stripping water heat exchanger. Background Technology

[0002] Methanol-to-olefins (MTO) is a process that uses methanol as a raw material to produce low-carbon olefins (ethylene and propylene). In a fluidized bed reactor, methanol reacts with the active sites of a catalyst to generate reaction gases containing ethylene and propylene as the target products. The reaction process produces side reactions, generating small amounts of heavy olefins and oxides as byproducts.

[0003] In the MTO process, the target product is washed with water and alkali to wash off oxides in the reaction gas and neutralize organic acids. The wash water is then separated from the heavy distillate hydrocarbons in the by-products by passing through equipment such as a water washing tower and an oil-water separator before being sold externally. Part of the wastewater is discharged directly, while the other part is stripped to reduce oxides in the wastewater before being discharged to the sewage treatment plant.

[0004] After being treated with alkaline washing and other methods, oxides and other byproducts from the MTO reaction easily accumulate as polycyclic aromatic hydrocarbons on poorly flowing surfaces of the heat exchanger in the wastewater stripping section, leading to decreased heat exchange efficiency. Stripping water heat exchangers are prone to blockage due to these polycyclic aromatic hydrocarbon byproducts, requiring frequent emptying, replacement, and core flushing. Furthermore, the compact internal structure of U-tube heat exchangers makes high-pressure water flushing ineffective. Summary of the Invention

[0005] The purpose of this invention is to provide a descaling device for a methanol-to-olefins stripping water heat exchanger, which solves the problems of scaling, clogging, and difficulty in cleaning the stripping water heat exchanger. It uses self-produced by-product heavy distillate hydrocarbons as a solvent for descaling, without increasing additional expenses, and improves the maintenance effect of the heat exchanger.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this utility model is as follows:

[0007] A descaling device for a methanol-to-olefins stripping water heat exchanger includes a stripping water heat exchanger, characterized in that it further includes a heavy distillate hydrocarbon buffer tank and a methanol ground tank, wherein the heavy distillate hydrocarbon buffer tank is connected to the stripping water inlet of the stripping water heat exchanger via a pipeline, and the stripping water outlet of the stripping water heat exchanger is connected to the methanol ground tank via a pipeline.

[0008] Furthermore, a heavy distillate hydrocarbon transfer valve is installed on the connecting pipe between the heavy distillate hydrocarbon buffer tank and the stripping water inlet of the stripping water heat exchanger, through which the heavy distillate hydrocarbons are transported to the stripping water heat exchanger.

[0009] Furthermore, a heavy distillate hydrocarbon discharge valve is installed on the connecting pipe between the stripping water outlet of the stripping water heat exchanger and the methanol tank, through which heavy distillate hydrocarbons in the stripping water heat exchanger are discharged to the methanol tank.

[0010] Preferably, the heavy distillate hydrocarbons enter the stripping water heat exchanger from the bottom and are discharged to the methanol tank from the top.

[0011] Furthermore, in the stripping water heat exchanger, stripping water enters the heat exchanger through a stripping water inlet valve 1 and a stripping water inlet valve 2, and after heat exchange, the stripping water flows out of the heat exchanger through a stripping water outlet valve 1 and a stripping water outlet valve 2.

[0012] To restore the heat exchange efficiency of the stripping water heat exchanger, based on the physicochemical properties of the heavy distillate hydrocarbons produced by the MTO unit, this utility model provides a descaling device for the stripping water heat exchanger. The device utilizes the heavy distillate hydrocarbons to dissolve the scale on the stripping water heat exchanger. By changing the process flow, a process is added from the heavy distillate hydrocarbons to the stripping water heat exchanger and from the stripping water heat exchanger to the methanol underground tank. The heavy distillate hydrocarbons are transported to the stripping water heat exchanger, cleaned, and then discharged to the methanol underground tank, and finally discharged through the original methanol underground tank.

[0013] Beneficial effects: The descaling device for the methanol-to-olefins (MTO) stripping water heat exchanger of this utility model uses heavy distillate hydrocarbons, a byproduct of the MTO unit, to dissolve the scale inside the stripping water heat exchanger, thereby further improving the heat exchange efficiency of the equipment and reducing the energy consumption of the unit. Attached Figure Description

[0014] Figure 1 This utility model presents a structural diagram of a descaling device for a methanol-to-olefins stripping water heat exchanger.

[0015] In the diagram, 1-stripping water heat exchanger, 2-heavy distillate hydrocarbon buffer tank, 3-methanol ground tank, 4-heavy distillate hydrocarbon transfer valve, 5-heavy distillate hydrocarbon discharge valve, 6-stripping water inlet valve, 7-stripping water inlet valve, 8-stripping water outlet valve, 9-stripping water outlet valve. Detailed Implementation

[0016] The specific embodiments of this utility model will be described in detail below. However, it should be noted that the scope of protection of this utility model is not limited by these specific embodiments, but is determined by the claims.

[0017] like Figure 1As shown, the descaling device for the methanol-to-olefins (MTO) stripping water heat exchanger utilizes heavy distillate hydrocarbons, a byproduct of MTO, to dissolve scale or blockages in the stripping water heat exchanger. The device includes a stripping water heat exchanger 1, a heavy distillate hydrocarbon buffer tank 2, and a methanol ground tank 3. The stripping water heat exchanger 1 is a device that requires maintenance or chemical cleaning to improve its heat exchange efficiency. The stripping water heat exchanger 1 originally has a first stripping water inlet valve 6 and a second stripping water inlet valve 7 at its inlet, and a first stripping water outlet valve 8 and a second stripping water outlet valve 8 at its outlet. In the device, the heavy distillate hydrocarbon buffer tank 2 is connected to the stripping water inlet of the stripping water heat exchanger 1 via a pipeline, and the stripping water outlet of the stripping water heat exchanger 1 is connected to the methanol tank 3 via a pipeline. A heavy distillate hydrocarbon delivery valve 4 and a heavy distillate hydrocarbon discharge valve 5 are respectively installed before and after the stripping water heat exchanger 1. Heavy distillate hydrocarbons are transported into the stripping water heat exchanger 1 through the heavy distillate hydrocarbon delivery valve 4, and discharged into the methanol tank 3 through the heavy distillate hydrocarbon discharge valve 5. The heavy distillate hydrocarbon delivery valve 4 controls the flow rate of heavy distillate hydrocarbons entering the stripping water heat exchanger 1; the heavy distillate hydrocarbon discharge valve 5 controls the flow rate of heavy distillate hydrocarbons discharged after the stripping water heat exchanger 1 is washed. After the stripping water inlet and outlet valves 6 and 7 of the stripping water heat exchanger 1 are closed, the original stripping water heat exchange process is isolated. First, the heavy distillate hydrocarbon discharge valve 5 is opened to equalize the pressure of the heavy distillate hydrocarbon entering the stripping water heat exchanger 1. Then, the heavy distillate hydrocarbon delivery valve 4 is opened for flushing and liquefaction washing. The hydrocarbon is then discharged to the methanol tank 3 through the heavy distillate hydrocarbon discharge valve 5.

[0018] The stripping water heat exchanger 1 is a shell-and-tube heat exchanger. Stripping water or heavy distillate hydrocarbons flow through the shell side, enter the stripping water heat exchanger 1 from the bottom, and exit from the top.

Claims

1. A descaling device for a methanol-to-olefins stripping water heat exchanger, comprising a stripping water heat exchanger (1), characterized in that, It also includes a heavy distillate hydrocarbon buffer tank (2) and a methanol ground tank (3). The heavy distillate hydrocarbon buffer tank (2) is connected to the stripping water inlet of the stripping water heat exchanger (1) through a pipeline, and the stripping water outlet of the stripping water heat exchanger (1) is connected to the methanol ground tank (3) through a pipeline.

2. The descaling device for a methanol-to-olefins stripping water heat exchanger according to claim 1, characterized in that, The heavy distillate hydrocarbon buffer tank (2) is connected to the stripping water heat exchanger (1) and a heavy distillate hydrocarbon delivery valve (4) is installed on the connecting pipe.

3. The descaling device for a methanol-to-olefins stripping water heat exchanger according to claim 1, characterized in that, A heavy distillate hydrocarbon discharge valve (5) is installed on the connecting pipe between the stripping water outlet of the stripping water heat exchanger (1) and the methanol tank (3).

4. The descaling device for a methanol-to-olefins stripping water heat exchanger according to claim 1, characterized in that, In the stripping water heat exchanger (1), stripping water enters through the stripping water inlet through the first stripping water inlet valve (6) and the second stripping water inlet valve (7), and after heat exchange, the stripping water flows out through the stripping water outlet through the first stripping water outlet valve (8) and the second stripping water outlet valve (9).

5. The descaling device for a methanol-to-olefins stripping water heat exchanger according to claim 1, characterized in that, The heavy distillate hydrocarbons enter the stripping water heat exchanger (1) from the bottom and are discharged from the top to the methanol tank (3).

Images