Refined alcohol pre-rectifying tower process device utilizing low-grade heat energy
By adding an extractor and pressure detector to the pre-distillation column to maintain negative pressure operation, and by utilizing low-grade heat sources and low-temperature condensation, combined with heat exchangers and pressurized distillation columns, the problem of wasted heat and cold sources in existing technologies is solved, achieving energy saving and consumption reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 新疆心连心能源化工有限公司
- Filing Date
- 2025-06-30
- Publication Date
- 2026-05-19
AI Technical Summary
The existing alcohol pre-distillation column process consumes low-pressure steam at the bottom and a large amount of circulating water at the top under normal operating pressure, resulting in waste of heat and cold sources.
By adding an extractor and pressure detector to the pre-distillation column to maintain negative pressure operation, and by using a low-grade heat source and low-temperature condensation, combined with a heat exchanger and a pressurized distillation column, the consumption of steam and cooling water is reduced.
It effectively reduces the steam consumption and cooling water usage of the pre-distillation column, improves energy efficiency, and reduces operating costs.
Smart Images
Figure CN224252131U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of crude alcohol process equipment, and is a process equipment for a refined alcohol pre-distillation tower that utilizes low-grade thermal energy. Background Technology
[0002] The existing pre-distillation process for crude alcohol uses low-pressure steam (such as 0.5 MPa steam) as the heat source for the reboiler at the bottom of the column. The crude alcohol undergoes multiple partial vaporizations and condensations within the pre-distillation column, and the light components and acidic media in the crude alcohol are removed in gaseous form at the top of the column. The gaseous phase at the top of the column is condensed through a multi-stage circulating water heat exchanger, and the condensate is used as top reflux. The uncondensed gaseous phase is discharged to the flare system.
[0003] Under normal operating pressure, the boiling points of crude alcohol and light component impurities in the existing pre-distillation column are relatively high. The reboiler at the bottom of the pre-distillation column needs to provide a heat source with a high temperature, and the gas phase (light components) at the top of the column with a high temperature needs to provide a large amount of circulating water for condensation and cooling. Therefore, the existing pre-distillation column process consumes low-pressure steam at the bottom of the column and consumes a large amount of circulating water at the top of the column, resulting in a waste of heat and cold sources. Summary of the Invention
[0004] This invention provides a process device for a pre-distillation column of refined alcohol that utilizes low-grade thermal energy, overcoming the shortcomings of the prior art. It can effectively solve the problem that existing pre-distillation columns of refined alcohol consume low-pressure steam at the bottom and a large amount of circulating water at the top under normal operating pressure, resulting in waste of heat and cold sources.
[0005] The technical solution of this utility model is achieved through the following measures: a pre-distillation tower process device for refined alcohol utilizing low-grade thermal energy, comprising a pre-distillation tower, a separator, and a first reboiler. The upper inlet of the pre-distillation tower is fixedly connected to a crude alcohol feed pipeline. The top outlet of the pre-distillation tower is fixedly connected to the inlet of the separator, and a first gas phase pipeline is fixedly connected to it. A condenser is installed on the first gas phase pipeline. The bottom outlet of the separator is fixedly connected to the upper inlet of the pre-distillation tower, and a condensate reflux pipeline is fixedly connected to it. The top outlet of the separator is fixedly connected to a second gas phase pipeline. The bottom outlet of the pre-distillation tower is fixedly connected to the bottom inlet of the first reboiler, and a first reflux feed pipeline is fixedly connected to the top outlet of the first reboiler and the lower inlet of the pre-distillation tower. An extractor and a valve are sequentially installed on the second gas phase pipeline, and a pressure detector is installed at the top of the pre-distillation tower.
[0006] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:
[0007] The above also includes a second reboiler, with a second reflux discharge line fixedly connected between the bottom outlet of the pre-distillation column and the bottom inlet of the second reboiler, and a second reflux feed line fixedly connected between the top outlet of the second reboiler and the lower inlet of the pre-distillation column.
[0008] The above also includes a heat exchanger and a pressurized distillation column. A heat exchanger is installed on the crude alcohol feed line. A first refined alcohol discharge line is fixedly connected between the heat source inlet of the heat exchanger and the bottom outlet of the pre-distillation column. A second refined alcohol discharge line is fixedly connected between the heat source outlet of the heat exchanger and the upper inlet of the pressurized distillation column. A third gas phase line is fixedly connected to the top outlet of the pressurized distillation column. A third refined alcohol discharge line is fixedly connected to the bottom outlet of the pressurized distillation column.
[0009] The first and second refined alcohol discharge pipelines are both equipped with heat tracing cables, and the outside of the heat tracing cables is provided with an insulation layer, which is made of rock wool or aluminum silicate fiber blanket.
[0010] The inlet and outlet of the first reboiler heat source are respectively fixedly connected to a low-grade heat source inlet pipeline and a low-grade heat source outlet pipeline, the inlet and outlet of the second reboiler heat source are respectively fixedly connected to a low-pressure steam inlet pipeline and a low-pressure steam outlet pipeline, and the inlet and outlet of the condenser cold source are respectively fixedly connected to a cooling water inlet pipeline and a cooling water outlet pipeline.
[0011] The pre-distillation column is equipped with a temperature detector at the bottom.
[0012] Both the condensate return line and the first refined alcohol discharge line are equipped with transfer pumps.
[0013] This utility model has a reasonable and compact structure and is easy to use. By adding an extractor and a pressure detector to the second gas phase pipeline, the operating pressure of the pre-distillation column is maintained under negative pressure. Under negative pressure, the operating temperature of the pre-distillation column will be greatly reduced. As a result, the heat source of the first reboiler at the bottom of the pre-distillation column only needs to be a low-grade heat source of 60°C, which greatly reduces the steam consumption of the pre-distillation column process. At the same time, it reduces the consumption of cooling water in the condenser at the top of the pre-distillation column. Attached Figure Description
[0014] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0015] Appendix Figure 1 The codes in the diagram are as follows: 1 for pre-distillation column, 2 for separator, 3 for first reboiler, 4 for crude alcohol feed line, 5 for first vapor phase line, 6 for condenser, 7 for condensate reflux line, 8 for second vapor phase line, 9 for first refined alcohol discharge line, 10 for first reflux feed line, 11 for first reflux discharge line, 12 for extractor, 13 for valve, 14 for pressure detector, 15 for second reboiler, 16 for second reflux feed line, 17 for second reflux discharge line, 18 for heat exchanger, 19 for pressurized distillation column, 20 for second refined alcohol discharge line, 21 for third vapor phase line, 22 for third refined alcohol discharge line, 23 for temperature detector, and 24 for transfer pump. Detailed Implementation
[0016] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.
[0017] Unless otherwise specified, all equipment and devices used in this invention are existing and commonly known in the art. For example, the pre-distillation column, extractor 12, heat exchanger 18, condenser 6, and pressure detector 14 are existing and commonly known equipment.
[0018] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.
[0019] The present invention will be further described below with reference to the embodiments and accompanying drawings:
[0020] Example 1: As shown in the attached document Figure 1 As shown, the pre-distillation tower process unit for refined alcohol utilizing low-grade thermal energy includes a pre-distillation tower 1, a separator 2, and a first reboiler 3. The upper inlet of the pre-distillation tower 1 is fixedly connected to a crude alcohol feed line 4. The top outlet of the pre-distillation tower 1 is fixedly connected to the inlet of the separator 2 via a first gas phase line 5. A condenser 6 is installed on the first gas phase line 5. The bottom outlet of the separator 2 is fixedly connected to the upper inlet of the pre-distillation tower 1 via a condensate reflux line 7. The top outlet of the separator 2 is fixedly connected to a second gas phase line 8. The bottom outlet of the pre-distillation tower 1 is fixedly connected to the bottom inlet of the first reboiler 3 via a first reflux discharge line 11. The top outlet of the first reboiler 3 is fixedly connected to the lower inlet of the pre-distillation tower 1 via a first reflux feed line 10. An extractor 12 and a valve 13 are sequentially installed on the second gas phase line 8. A pressure detector 14 is installed at the top of the pre-distillation tower 1.
[0021] In this invention, by adding an extractor 12 and a pressure detector 14 to the second gas phase pipeline 8, the operating pressure of the pre-distillation column 1 is maintained at a negative pressure (-30 kPa and below). Under negative pressure conditions, the operating temperature of the pre-distillation column 1 will be significantly reduced, decreasing by about 60°C from approximately 72°C to 73°C. With this reduced operating temperature, the original first reboiler 3 at the bottom of the pre-distillation column 1 used low-pressure steam (e.g., 0.5 MPa steam) as a heat source; now, only a low-grade heat source at 60°C is needed. This greatly reduces the steam consumption of the pre-distillation column 1 process and also reduces the consumption of cooling water in the condenser 6 at the top of the pre-distillation column 1.
[0022] The above-mentioned process unit for the pre-distillation column of refined alcohol utilizing low-grade heat energy can be further optimized and / or improved according to actual needs:
[0023] Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, it also includes a second reboiler 15, a second reflux discharge line 17 is fixedly connected between the bottom outlet of the pre-distillation column 1 and the bottom inlet of the second reboiler 15, and a second reflux feed line 16 is fixedly connected between the top outlet of the second reboiler 15 and the lower inlet of the pre-distillation column 1.
[0024] During use, the second reboiler 15 serves as a backup. When the extractor 12 malfunctions and the unit cannot operate under negative pressure, the second reboiler 15 at the bottom of the pre-distillation column 1 is used. The second reboiler 15 uses low-pressure steam as a heat source to ensure the normal operation of the pre-distillation column 1.
[0025] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, it also includes a heat exchanger 18 and a pressurized distillation column 19. The crude alcohol feed line 4 is equipped with a heat exchanger 18. The heat source inlet of the heat exchanger 18 is fixedly connected to the bottom outlet of the pre-distillation column 1 by a first refined alcohol discharge line 9. The heat source outlet of the heat exchanger 18 is fixedly connected to the upper inlet of the pressurized distillation column 19 by a second refined alcohol discharge line 20. The top outlet of the pressurized distillation column 19 is fixedly connected to a third gas phase line 21. The bottom outlet of the pressurized distillation column 19 is fixedly connected to a third refined alcohol discharge line 22.
[0026] During use, by adding a heat exchanger 18, the low-temperature crude alcohol raw material is effectively exchanged with the high-temperature refined alcohol coming out of the bottom of the pre-distillation column 1, which further saves energy consumption; the refined alcohol coming out of the bottom of the pre-distillation column 1 is sent to the pressurized distillation column 19 for further processing by the first refined alcohol discharge pipeline 9 and the second refined alcohol discharge pipeline 20.
[0027] Example 4: It differs from Example 3 in that, as shown in the attached document... Figure 1 As shown, both the first refined alcohol discharge pipeline 9 and the second refined alcohol discharge pipeline 20 are equipped with heat tracing cables, and both heat tracing cables are provided with an insulation layer on the outside. The insulation layer material is rock wool or aluminum silicate fiber blanket.
[0028] During use, the insulation layer installed on the first refined alcohol discharge pipeline 9 and the second refined alcohol discharge pipeline 20 can reduce heat loss, improve energy utilization efficiency, and save operating costs.
[0029] As needed, the inlet and outlet of the first reboiler 3 are fixedly connected to a low-grade heat source inlet pipeline and a low-grade heat source outlet pipeline, respectively; the inlet and outlet of the second reboiler 15 are fixedly connected to a low-pressure steam inlet pipeline and a low-pressure steam outlet pipeline, respectively; and the inlet and outlet of the condenser 6 are fixedly connected to a cooling water inlet pipeline and a cooling water outlet pipeline, respectively.
[0030] During operation, the first reboiler 3 uses a low-grade heat source at a temperature of about 60℃ as the heat source, and the second reboiler 15 uses low-pressure steam as the heat source to ensure the normal operation of the pre-distillation column 1.
[0031] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, a temperature detector 23 is installed at the bottom of the pre-distillation column 1.
[0032] During use, temperature detector 23 can monitor the bottom temperature of pre-distillation column 1 in real time to ensure the normal operation of the unit.
[0033] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1 As shown, both the condensate return line 7 and the first refined alcohol discharge line 9 are equipped with a transfer pump 24.
[0034] If necessary, the extractor 12 can be a fan.
[0035] Depending on the needs, the pipelines and equipment of the alcohol pre-distillation tower process unit utilizing low-grade heat energy may also be equipped with conventional valves, thermometers, and pressure gauges known and commonly used in the field, according to production requirements.
[0036] The above technical features constitute the embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
[0037] The process of using this utility model is as follows: First, close valve 13 and open the extractor 12 to evacuate the device. When the pressure detector 14 detects that the pressure at the top of the pre-distillation column 1 is maintained at -30kPa or below, the operating temperature of the pre-distillation column 1 drops significantly, from about 72℃ to 73℃ to about 60℃.
[0038] Then, crude alcohol is fed into pre-distillation column 1 via crude alcohol feed line 4, and the first reboiler 3 is heated using low-grade heat energy at about 60°C. The crude alcohol in pre-distillation column 1 is distilled, and the gas phase (light component) at the top of the column is sent to condenser 6 for cooling. The cooled gas phase is condensed and separated in separator 2. The uncondensed gas phase is sent to the subsequent flare treatment via second gas phase line 8, and the condensate at the bottom of separator 2 is sent to pre-distillation column 1 for reflux.
[0039] Finally, the higher-temperature refined alcohol at the bottom of the pre-distillation column 1 is sent to the heat exchanger 18 to exchange heat with the lower-temperature crude alcohol. After heat exchange, the refined alcohol is sent to the pressurized distillation column 19 through the second refined alcohol outlet pipeline 20 for subsequent processes.
Claims
1. A pre-distillation column process device for alcohols utilizing low-grade thermal energy, characterized in that... The system includes a pre-distillation column, a separator, and a first reboiler. The upper inlet of the pre-distillation column is fixedly connected to a crude alcohol feed line. A first vapor phase line is fixedly connected between the top outlet of the pre-distillation column and the inlet of the separator, with a condenser installed on the first vapor phase line. A condensate reflux line is fixedly connected between the bottom outlet of the separator and the upper inlet of the pre-distillation column. A second vapor phase line is fixedly connected between the bottom outlet of the pre-distillation column and the bottom inlet of the first reboiler. A first reflux feed line is fixedly connected between the top outlet of the first reboiler and the lower inlet of the pre-distillation column. An extractor and a valve are sequentially installed on the second vapor phase line. A pressure detector is installed at the top of the pre-distillation column.
2. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 1, characterized in that... It also includes a second reboiler, with a second reflux discharge line fixedly connected between the bottom outlet of the pre-distillation column and the bottom inlet of the second reboiler, and a second reflux feed line fixedly connected between the top outlet of the second reboiler and the lower inlet of the pre-distillation column.
3. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 1 or 2, characterized in that... It also includes a heat exchanger and a pressurized distillation column. A heat exchanger is installed on the crude alcohol feed line. A first refined alcohol discharge line is fixedly connected between the heat source inlet of the heat exchanger and the bottom outlet of the pre-distillation column. A second refined alcohol discharge line is fixedly connected between the heat source outlet of the heat exchanger and the upper inlet of the pressurized distillation column. A third gas phase line is fixedly connected to the top outlet of the pressurized distillation column. A third refined alcohol discharge line is fixedly connected to the bottom outlet of the pressurized distillation column.
4. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 3, characterized in that... Both the first and second refined alcohol discharge pipelines are equipped with heat tracing cables, and the outer side of the heat tracing cables is provided with an insulation layer, which is made of rock wool or aluminum silicate fiber blanket.
5. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 2 or 4, characterized in that... The inlet and outlet of the first reboiler heat source are fixedly connected to a low-grade heat source inlet pipeline and a low-grade heat source outlet pipeline, respectively. The inlet and outlet of the second reboiler heat source are fixedly connected to a low-pressure steam inlet pipeline and a low-pressure steam outlet pipeline, respectively. The inlet and outlet of the condenser cold source are fixedly connected to a cooling water inlet pipeline and a cooling water outlet pipeline, respectively.
6. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 3, characterized in that... The inlet and outlet of the first reboiler heat source are fixedly connected to a low-grade heat source inlet pipeline and a low-grade heat source outlet pipeline, respectively. The inlet and outlet of the second reboiler heat source are fixedly connected to a low-pressure steam inlet pipeline and a low-pressure steam outlet pipeline, respectively. The inlet and outlet of the condenser cold source are fixedly connected to a cooling water inlet pipeline and a cooling water outlet pipeline, respectively.
7. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 4 or 6, characterized in that... A temperature detector is installed at the bottom of the pre-distillation column; and / or a transfer pump is installed on the condensate reflux line and the first refined alcohol discharge line.
8. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 3, characterized in that... A temperature detector is installed at the bottom of the pre-distillation column; and / or a transfer pump is installed on the condensate reflux line and the first refined alcohol discharge line.
9. The pre-distillation column process apparatus for alcohols utilizing low-grade thermal energy according to claim 5, characterized in that... A temperature detector is installed at the bottom of the pre-distillation column; and / or a transfer pump is installed on the condensate reflux line and the first refined alcohol discharge line.