Cascade utilization system for high-quality condensed water

Abstract

The utility model discloses a high-quality condensed water cascade utilization system, and belongs to the technical field of petrochemical refining equipment. The system comprises a refining tower (7), a tower kettle of the refining tower (7) is connected with a reboiler (8) through a circulating pipeline, the reboiler (8) is connected with a low-temperature steam pipeline (1), and the low-temperature steam pipeline (1) is connected with a high-quality condensed water vapor generating assembly. According to the utility model, the high-quality condensed water is subjected to flash evaporation to obtain low-temperature steam by utilizing the flash evaporation tank, so that the flash evaporation tank is prevented from being repeatedly added, multiple purposes are realized, the equipment investment is reduced, the waste heat of the high-quality condensed water is supplemented to the low-temperature reboiler, and the use amount of the low-temperature steam is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of petrochemical refining equipment, and in particular relates to a cascade utilization system of high-quality condensate water for reboiling in a refining tower kettle. Background Art

[0002] In most of the current ethylene polymerization units, the bottoms of the light removal tower, heavy removal tower, C8 tower and C10 tower are heated by medium-pressure steam, which will produce condensate with a temperature of about 250°C (pressure-maintaining state). The usual practice is to directly merge this part of condensate into the condensate network. However, due to the high temperature and high pressure of these condensate, after directly entering the low-temperature condensate, the pressure will drop rapidly and flash steam will appear quickly, resulting in insufficient pipe filling, water hammer, and affecting safe operation; and if it is directly merged into the low-pressure steam heater, the efficiency of the heat exchanger will be reduced, affecting the heat transfer effect.

[0003] These high-temperature condensate waters are incorporated into the low-temperature condensate water system, which not only causes energy waste, but also increases the cooling load of the subsequent condensate water recovery system, requiring a larger cooling system and circulating water. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies in existing products and provide a high-quality condensate cascade utilization system for realizing reasonable utilization of waste heat.

[0005] In order to achieve the above-mentioned purpose, the utility model provides the following technical solution: a high-quality condensate cascade utilization system, comprising a refining tower, the kettle of the refining tower is connected to a reboiler through a circulation pipeline, the reboiler is connected to a low-temperature steam pipeline, and the characteristic is that a high-quality condensate steam generating component is connected to the low-temperature steam pipeline.

[0006] Specifically, the high-quality condensate steam generating assembly includes a high-quality condensate pipeline group, a flash tank and a steam pipeline. The high-quality condensate pipeline group is connected to the water inlet of the flash tank, and the steam outlet at the top of the flash tank is connected to the low-temperature steam pipeline through a steam pipeline; the condensate pipeline of the reboiler is connected back to the flash tank.

[0007] Specifically, the high-quality condensate water is condensate water with a temperature higher than 140° C. (maintaining pressure).

[0008] Specifically, the high-quality condensate water pipeline group is a parallel light removal tower condensate water pipeline, a heavy removal tower condensate water pipeline, a carbon eight tower condensate water pipeline and a carbon ten tower condensate water pipeline.

[0009] Specifically, the bottom of the flash tank is connected with a condensate discharge pipeline.

[0010] Preferably, a flow regulating valve is provided on the low-temperature steam pipeline.

[0011] Preferably, the light removal tower condensate water pipeline, the heavy removal tower condensate water pipeline, the carbon eight tower condensate water pipeline and the carbon ten tower condensate water pipeline are all provided with flow regulating valves.

[0012] Compared with the prior art, the beneficial effect of the high-quality condensate cascade utilization system of the utility model is as follows: the high-quality condensate produced by the preceding towers in the utility model enters the flash tank of the bottom heating system of the refining tower that needs low-temperature steam heating later through a pipeline, and the high-quality condensate is flashed after decompression using its own heat, and the flashed steam is returned to the reboiler inlet of the refining tower for heating the refining tower. The condensate after flashing absorbs heat due to vaporization, and its temperature drops to the saturation temperature under the current pressure. Through this system, the waste heat of high-quality condensate is utilized, the consumption of low-pressure steam is reduced, and the cooling load of the back-end system is reduced, which can reduce equipment investment and circulating water energy consumption.

[0013] In summary, the utility model uses a flash tank (low-temperature condensate tank) to flash the high-quality condensate produced by each tower into low-temperature steam, avoiding repeated addition of flash tanks, achieving multiple uses of one tank, reducing equipment investment, and also using the waste heat of the high-quality condensate to supplement the low-temperature reboiler, reducing the use of low-temperature steam and saving steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a high-quality condensate cascade utilization system of the utility model.

[0015] Among them: 1. Low-temperature steam pipeline 2. Light removal tower condensate pipeline 3. Heavy removal tower condensate pipeline 4. C8 tower condensate pipeline 5. C10 tower condensate pipeline 6. Condensate discharge pipeline 7. Refining tower 8. Reboiler 9. Flash tank. DETAILED DESCRIPTION

[0016] The following is combined with Figure 1 The embodiments of the present invention are described in more detail with reference to the accompanying drawings, so that a person skilled in the art can implement the present invention after reading the specification.

[0017] Refer to the attached Figure 1 :The utility model is a high-quality condensate cascade utilization system, comprising a low-temperature steam pipeline 1, a light-removal tower condensate pipeline 2, a heavy-removal tower condensate pipeline 3, a carbon-eight tower condensate pipeline 4, a carbon-ten tower condensate pipeline 5, a condensate discharge pipeline 6, a refining tower 7, a reboiler 8 and a flash tank 9. The kettle of the refining tower 7 is connected to the reboiler 8 through a circulation pipeline, and the reboiler 8 is connected to the low-temperature steam pipeline 1. The low-temperature steam pipeline 1 is provided with a flow regulating valve, which can be adjusted according to the gas supply situation of the flash tank.

[0018] The low-temperature steam pipeline 1 is connected to a high-quality condensate steam generating assembly, which can use high-quality condensate to replenish the low-temperature steam in the low-temperature steam pipeline 1, thereby reducing the amount of low-temperature steam used.

[0019] Specifically, the high-quality condensate steam generating component includes a high-quality condensate pipeline group, a flash tank 9 and a steam pipeline. The high-quality condensate pipeline group is a light-removal tower condensate pipeline 2, a heavy-removal tower condensate pipeline 3, a carbon-eight tower condensate pipeline 4 and a carbon-ten tower condensate pipeline 5 which are connected in parallel and each independently provided with a flow regulating valve. Each pipeline is connected to the water inlet of the flash tank 9 to introduce the high-quality condensate with a temperature higher than 140°C generated by the light-removal tower, the heavy-removal tower, the carbon-eight tower and the carbon-ten tower into the flash tank 9. In the flash tank 9, the high-quality condensate is flash evaporated after decompression using its own heat to obtain low-temperature steam. The low-temperature steam is replenished into the low-temperature steam pipeline 1 from the steam outlet at the top through the steam pipeline to heat the reboiler 8. The low-temperature steam is condensed by heat exchange in the reboiler 8, and the condensate returns to the flash tank 9 through the condensate pipeline of the reboiler 8. The bottom of the flash tank 9 is connected with a condensate discharge pipeline 6.

[0020] The above are one or more embodiments of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A high-quality condensate cascade utilization system, comprising a refining tower (7), the tower kettle of the refining tower (7) is connected to a reboiler (8) via a circulation pipeline, and the reboiler (8) is connected to a low-temperature steam pipeline (1), characterized in that: The low-temperature steam pipeline (1) is connected to a high-quality condensed water vapor generating component.

2. The high-quality condensate cascade utilization system according to claim 1 is characterized in that: The high-quality condensate steam generating assembly comprises a high-quality condensate pipeline group, a flash tank (9) and a steam pipeline, wherein the high-quality condensate pipeline group is connected to the water inlet of the flash tank (9), and the steam outlet at the top of the flash tank (9) is connected to the low-temperature steam pipeline (1) through a steam pipeline; the condensate pipeline of the reboiler (8) is connected back to the flash tank (9).

3. A high-quality condensate cascade utilization system according to claim 1 or 2, characterized in that: The high-quality condensed water is condensed water with a temperature higher than 140°C.

4. The high-quality condensate cascade utilization system according to claim 2 is characterized in that: The high-quality condensate pipeline group comprises a light-removal tower condensate pipeline (2), a heavy-removal tower condensate pipeline (3), a carbon eight tower condensate pipeline (4) and a carbon ten tower condensate pipeline (5) connected in parallel.

5. The high-quality condensate cascade utilization system according to claim 2 is characterized in that: The bottom of the flash tank (9) is connected to a condensate discharge pipeline (6).

6. The high-quality condensate cascade utilization system according to claim 2 is characterized in that: The low-temperature steam pipeline (1) is provided with a flow regulating valve.

7. The high-quality condensate cascade utilization system according to claim 4 is characterized in that: The light-removal tower condensate water pipeline (2), the heavy-removal tower condensate water pipeline (3), the carbon eight tower condensate water pipeline (4) and the carbon ten tower condensate water pipeline (5) are all provided with flow regulating valves.

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