Rectifying tower reflux device

Abstract

The utility model relates to the technical field of rectifying towers, in particular to a rectifying tower reflux device, which is characterized in that on the basis of the existing rectifying tower equipment, a hot reflux pipeline is additionally arranged to convey hot oil at the tower bottom to the tower top from the tower bottom, so that the tower bottom and the tower top can be simultaneously heated, the heating rate of the rectifying tower is improved, and the energy consumption in the heating process is reduced. In addition, emergency situations such as power failure in the production process can be avoided, the temperature of the whole rectifying tower can be adjusted through a hot backflow pipeline under the similar situations, and safety accidents caused by negative pressure due to too fast local temperature rise are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of distillation columns, in particular to a reflux device for a distillation column. Background Art

[0002] Distillation columns are widely used in industrial fields such as chemical engineering and petroleum, separating mixtures by the different volatilities of substances among the mixtures.

[0003] In the production process of naphtha, the distillation column plays a crucial role. In naphtha production, the distillation column can separate the mixture obtained from the preliminary processing of crude oil according to different boiling ranges to obtain light component and heavy component products. To achieve efficient separation, the distillation column usually needs to precisely control operating conditions such as temperature, pressure, reflux ratio, etc., and cooperate with the tower structure design such as the type of tower plates and packing types. By reasonably using the distillation column, the quality and purity of naphtha products can be improved to meet the requirements of different industrial applications.

[0004] The naphtha material enters from the middle of the tower, and a reboiler is provided at the bottom of the tower. By heating, part of the liquid is vaporized, and the rising steam and the descending liquid conduct heat and mass transfer on the tower plates or packing. The concentration of the easily volatile component increases in the gas phase, and the concentration of the hardly volatile component increases in the liquid phase. A condensation reflux device is provided at the top of the distillation column to partially condense the rising steam into liquid, which is taken out as the top product, and the other part is refluxed into the tower to maintain the material balance and the mass and heat transfer process in the tower.

[0005] However, currently, only a reboiler is provided at the bottom of the distillation column, and the hot oil in the reboiler heats the entire distillation column from bottom to top. The heating of the hot oil in the reboiler is a process that needs to be gradual. Therefore, for the entire distillation column, the heating rate is slow, it takes a long time, there is a lot of energy consumption waste, and there will also be uneven heat dispersion on different tower plates or packing layers in the distillation column, thus affecting the separation of naphtha light components and heavy component products.

[0006] For large-scale production, the distillation columns used are usually huge in volume and high in energy consumption. In case of sudden power outages or other emergencies at the site, a huge pressure difference will be formed between the inside and outside of the distillation column under the action of temperature. When the power is restored, the pressure inside the distillation column changes rapidly, posing a huge safety hazard to construction workers.

[0007] Therefore, there is an urgent need in the market for a reflux device for a distillation column that can increase the heating rate inside the distillation column, make the tower plates or packing inside the distillation column evenly heated, and can avoid the influence of the external environment on the distillation column, ensuring the safety of on-site construction workers, optimizing the operation and design of the distillation column, improving the heating efficiency and energy-saving effect of the distillation column, increasing the production efficiency, and reducing the production cost. Summary of the Utility Model

[0008] To solve the problems mentioned in the background art and overcome the above deficiencies, the present utility model provides the following technical solutions:

[0009] A rectification column reflux device, the main body of which is a rectification column tower body. A reboiler is provided at the bottom of the rectification column. The reboiler is connected to a hot reflux pipe to complete the hot reflux cycle. A condensation reflux device is provided at the top of the rectification column;

[0010] There are two output ports on the rectification column. The products separated by the rectification column are respectively output from the light component output port at the top of the tower and the heavy component output port at the bottom of the tower, and the products are cooled and then sent out.

[0011] The bottom of the rectification column is a reboiler. When the rectification column starts to work, the bottom reboiler is opened. The hot oil in the reboiler heats up and emits heat, which is conducted from bottom to top in sequence. During the heating-up process of the rectification column, it is necessary to carry out staged heating according to the setting. The heating-up speed per hour is usually 30 - 50 °C. The required temperature ranges at the top and bottom of the rectification column are between 180 °C and 220 °C. If you want to reach this temperature, it takes at least 3 hours to heat up.

[0012] If staged heating is not carried out and rapid heating is performed, a large amount of heat will be concentrated at the bottom of the rectification column and it is difficult to transfer heat upward. The trays or packing in each layer of the rectification column cannot be uniformly heated. At the same time, when the temperature is rapidly increased and is relatively high, it is easy to cause safety accidents.

[0013] Therefore, in order to increase the heating-up rate of the rectification column and enable the trays or packing in the rectification column to be uniformly heated, the applicant improves the existing rectification column process. A hot reflux pipeline is added at the bottom of the rectification column to pump out the hot oil at the bottom and pour it from the top of the rectification column. The hot oil flows down step by step along the trays and packing in the rectification column from the top. The hot gas generated by the heating of the reboiler at the bottom is transmitted step by step from the bottom upward, increasing the heating-up rate of the rectification column and ensuring that the trays and packing in the rectification column can be uniformly heated.

[0014] The heavy component product is sent out through a pipeline at the heavy component output port at the bottom of the rectification column. The pipeline is a heavy component output pipeline;

[0015] Further, a bottom product delivery pump is provided on the heavy component output pipeline near the rectification column end. Along the output direction of the heavy component output pipeline, a cooler is connected after the bottom product delivery pump, which is convenient for sending out the heavy component product from the rectification column and collecting it uniformly;

[0016] Further, a hot reflux pipeline is provided on the heavy component output pipeline. The input end of the hot reflux pipeline is connected to the heavy component output pipeline, and the output end of the hot reflux pipeline is connected to the top of the distillation column;

[0017] Further, the input end of the hot reflux pipeline is arranged between the bottom product delivery pump and the cooler on the heavy component output pipeline, and a switch valve is provided;

[0018] A light component output port is provided at the top of the distillation column and is connected to a light component output pipeline through the light component output port to send out the light component product in the distillation column;

[0019] Further, on the light component output pipeline, along the output direction of the light component output pipeline, a cooler, a reflux drum, and a top product delivery pump are sequentially connected from front to back;

[0020] Although the temperature of the light component output port at the top of the distillation column is lower than that of the heavy component output port at the bottom, the state and quality of the collected light component product still need to be sampled and detected, and it can be sent out only after passing the detection;

[0021] Further, a sampling and detection device is provided on the top product delivery pump. If the light component product is unqualified, it needs to be sent back to the distillation column for separation again, and a reflux port is provided at the top of the distillation column;

[0022] Further, a light component reflux pipeline is provided on the light component output pipeline, and the unqualified light component product is sent back to the top of the distillation column through the light component reflux pipeline;

[0023] Further, the input port end of the light component reflux pipeline is between the top product delivery pump of the light component output pipeline and the output port of the light component output pipeline, and the output port end of the light component reflux pipeline is connected to the reflux port at the top of the distillation column;

[0024] A cold reflux device is provided at the top of the distillation column. When the quality of the light component product does not meet the requirements, the cold reflux device needs to be opened to cool down the top of the distillation column, so that the light component product at the top of the distillation column is further separated to obtain a light component product that meets the quality, and is sent out again from the light component output pipeline;

[0025] Further, the input end of the hot reflux pipeline is connected to the heavy component output pipeline. The input end of the hot reflux pipeline is arranged between the bottom product delivery pump and the cooler on the heavy component output pipeline. The output end of the hot reflux pipeline is connected to the light component reflux pipeline, and then the output end of the light component reflux pipeline is connected to the top of the distillation column;

[0026] Further, the length of the hot reflux pipeline is from the outlet of the bottom product delivery pump to the top of the tower. The pipeline length is between 20 and 30 meters, and the pipe diameter is the same as that of the cold reflux pipeline.

[0027] In actual use, the rectification tower hot reflux device can be used in different scenarios. When the rectification tower is first used, the reboiler and the switch valve of the hot reflux pipeline are used simultaneously. The reboiler is used to heat the bottom of the tower and dissipate heat towards the top of the rectification tower. The hot oil at the bottom of the tower is led out by the hot reflux device and poured down from the top of the tower for heat dissipation from top to bottom. Since the temperature of the led-out hot oil gradually increases with the change of the reboiler temperature, the overall heating rate of the rectification tower becomes faster, and the trays or packings in the rectification tower can all be heated, enabling the trays or packings to be heated evenly. Since only the hot reflux device supplies heat to the top of the tower, after the hot oil is poured down, heat will be lost, and the reboiler at the bottom of the rectification tower is always in the working state. In this way, it can be ensured that the trays or packings at the top and bottom of the rectification tower are in different temperature ranges, and the temperature difference can separate different products. When discharging, the switch valve of the hot reflux pipeline is closed, and the separated light-component products and heavy-component products are respectively output along the light-component output pipeline at the top of the rectification tower and the heavy-component output pipeline at the bottom of the tower.

[0028] When the products produced in the light-component output pipeline at the top of the tower do not meet the quality requirements, the cold reflux device located at the top of the tower is opened to cool the top of the tower. The condensed products flow down step by step along the trays or packings and finally are output from the heavy-component output pipeline, and the obtained light-component products are output from the light-component output pipeline.

[0029] When a sudden power failure occurs at the operation site, the temperature in the rectification tower is very high, and a pressure difference is formed with the outside under the action of the temperature. If power is suddenly restored, the temperature difference in the rectification tower changes suddenly, and it is easy to cause safety accidents under the action of pressure. Therefore, when power is restored, the switch valve of the hot reflux pipeline is opened to lead out the hot oil at the bottom of the tower and pour it down from the top of the tower, reducing the temperature difference between the bottom and the top of the tower and at the same time reducing the temperature difference between the rectification tower and the outside, enabling the entire rectification tower to quickly return to the state of uniform heating, reducing the incidence of on-site operation accidents, and ensuring the safety of operation personnel.

[0030] Compared with the prior art, the beneficial effects of the present utility model are:

[0031] 1. By improving the existing rectification tower, a hot reflux pipeline is added. During the startup process, the hot oil at the bottom of the tower is pumped into the top of the tower through this pipeline, controlling the uniform increase of the top temperature of the tower, shortening the feeding and heating time of the rectification tower, and reducing the consumption of natural gas by at least 1 / 2. During the operation process, when a power failure accident occurs, the top temperature of the tower drops rapidly and it is easy to form a negative pressure inside the tower. After power is restored, by opening the hot reflux pipeline, the top temperature of the tower can rise quickly, slowing down the pressure impact inside the tower and improving the safe use performance of the rectification tower.

[0032] 2. The input and output ends of the thermal reflux pipeline are arranged on the heavy component output pipeline and the light component reflux pipeline of the original distillation column. It can be improved by using the original distillation column, which reduces the production cost. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the reflux device of the distillation column of the present utility model;

[0034] 1 - distillation column, 2 - cooler, 3 - bottom product delivery pump, 4 - top product delivery pump, 5 - reflux drum, 6 - light component output pipeline, 61 - light component reflux pipeline, 7 - heavy component output pipeline, 8 - thermal reflux pipeline. Detailed Embodiments

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0036] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0037] Embodiment 1

[0038] As Figure 1 shown, with the distillation column 1 as the main body, two product output pipelines are arranged on the distillation column 1, namely the light component output pipeline 6 that needs to be output from the top of the column, which outputs the light component products at the top of the column; the other is the heavy component output pipeline 7 located at the bottom of the column, which outputs the separated heavy component products.

[0039] At the beginning of the operation, since the working principle of the distillation column 1 is to separate products with different distillation points by using the temperature change on the trays or packing arranged in the distillation column 1, there is a temperature difference from the bottom to the top of the distillation column 1, where the bottom temperature is the highest and the top temperature is relatively low.

[0040] The traditional distillation column 1 is heated at the bottom by a reboiler. However, during the gradient heating process, a large amount of natural gas is consumed for energy supply. If we want to ensure that the trays or packing in the distillation column 1 can be evenly heated, we can only do so by extending the heating time.

[0041] Therefore, on the basis of the existing lines of the traditional distillation column 1, a hot reflux line 8 is provided on the heavy component output line 7 at the bottom of the column to guide the hot oil at the bottom of the column to the top of the column and pour it down from the top of the column to increase the temperature at the top of the column. During the pouring process, the trays or packing in the column can also be heated.

[0042] In this way, by simultaneously using the bottom reboiler and the method of pouring hot oil at the top, the distillation column 1 can be quickly heated up, which not only saves the energy consumption of natural gas, but also enables the trays or packing in the column to be evenly heated.

[0043] On the heavy component output line 7, along the output direction of the heavy component product, a bottom product delivery pump 3 and a cooler 2 are successively arranged. The input end of the hot reflux line 8 can be arranged between the bottom product delivery pump 3 and the cooler 2 on the heavy component output line 7. In this way, the hot oil at the bottom of the column can be pumped out by the bottom product delivery pump 3 on the heavy component output line 7, which is convenient for sending the hot oil along the hot reflux line 8 to the top of the column.

[0044] On the light component output line 6, along the conveying direction of the light component output line 6, a cooler 2, a reflux drum 5, and a top product delivery pump 4 are successively connected from front to back. Behind the top product delivery pump 4, a light component reflux line 61 is provided between the output port of the light component output line 6.

[0045] A sampling and detection device is provided on the top product delivery pump 4 to detect the light component product from the light component output line 6. After passing the detection, it is directly sent out along the light component line 6. If the detection is unqualified, it returns to the reflux port at the top of the distillation column 1 through the light component reflux line 61 and enters the distillation column 1 from the reflux port.

[0046] A cold reflux device is provided at the top of the distillation column 1. When the light component product that does not meet the quality requirements returns to the top of the distillation column 1 along the light component reflux line 61, the cold reflux device is opened to cool down the distillation column 1, so that the gas-liquid mixture is re-separated on different trays or packing. The obtained light component product enters the light component output line 6, and the heavy component product enters the heavy component output line 7 and is sent out separately.

[0047] Example 2

[0048] Combined with Figure 1 Example 1, when there is product output, the switch valve of the hot reflux line 8 needs to be closed, and the hot reflux process is no longer carried out. Only the products are transported in the heavy component output line 7 and the light component reflux line 61 associated with the hot reflux line 8. The distillation column 1 mainly maintains the temperature inside the distillation column 1 by the heat generated by the hot oil in the bottom reboiler.

[0049] However, during the operation process, in case of a power outage accident at the operation site, the temperature at the top of the tower is relatively lower than that at the bottom of the tower. Therefore, after losing the heat supply source, the temperature at the top of the tower drops relatively fast. In the rectification tower 1, due to the temperature difference, a negative pressure is generated with the outside. When the power supply is restored, on the one hand, the local temperature in the tower rises rapidly, which is likely to cause a rapid change in the tower pressure and easily lead to safety accidents. On the other hand, the temperature recovery at the top of the tower is relatively slow, which is not conducive to quickly resuming the operation state.

[0050] Therefore, in case of a similar situation, after power-on, the on-off valve of the hot reflux pipeline 8 can be opened to redirect the hot oil at the bottom of the tower to the top of the tower again, avoiding the pressure change caused by local temperature rise and quickly increasing the temperature at the top of the tower, so that the rectification tower 1 can quickly return to the state during product production.

[0051] During the operation process, in case of a power outage accident, the temperature at the top of the tower drops relatively fast and a negative pressure is easily formed inside the tower. After the power supply is restored, by opening the hot reflux pipeline, the temperature at the top of the tower can rise relatively fast, reducing the pressure impact inside the tower and improving the safe operation performance of the rectification tower.

[0052] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A rectification column reflux device, comprising a rectification column (1), characterized in that: The top of the rectifying column (1) is provided with a light component output pipeline (6), the bottom of the rectifying column (1) is provided with a heavy component output pipeline (7), a hot reflux pipeline (8) is arranged on the heavy component output pipeline (7), and the output end of the hot reflux pipeline (8) is connected to the top of the rectifying column (1).

2. The reflux device of a rectifying column according to claim 1, characterized in that: A bottom product external delivery pump (3) and a cooler (2) are sequentially connected on the heavy component output pipeline (7); the input end of the hot reflux pipeline (8) is arranged between the bottom product external delivery pump (3) and the cooler (2), and a switch valve is provided.

3. The reflux device of a rectifying column according to claim 1, characterized in that: A cooler (2), a reflux drum (5), and a top product external delivery pump (4) are sequentially connected on the light component output pipeline (6); a light component reflux pipeline (61) is arranged between the top product external delivery pump (4) and the output port of the light component output pipeline (6).

4. The reflux device of a rectifying column according to claim 3, characterized in that: The light component reflux pipeline (61) is connected to the output end of the hot reflux pipeline (8), and the output end of the light component reflux pipeline (61) is connected to the top reflux port of the rectifying column (1).

5. The reflux device of a rectification column according to claim 1, wherein: The hot reflux pipeline (8) extends from the outlet of the bottom product external delivery pump to the top of the column, and the pipeline length is between 20 and 30 meters, and the pipe diameter is the same as that of the cold reflux pipeline.

6. The reflux device of a rectifying column according to claim 3, characterized in that: A sampling and detection device is also provided on the top product external delivery pump (4) on the light component output pipeline (6).

Images