Propane rectification system

Abstract

According to the propyl alcohol rectification system provided by the invention, heavy components such as propyl alcohol and propyl propionate in crude propyl alcohol can be separated through rectification of the propyl alcohol rectification tower and negative pressure rectification of the waste liquid rectification tower, so that the purposes of purifying and recovering the propyl alcohol are achieved, and the economic benefit is improved. Heat pump devices such as a heat pump compressor, a heat pump separator and a heat pump reboiler are also introduced into the system, so that the stability and the reliability of the operation of the rectifying tower are favorably maintained, and unstable production factors caused by fluctuation of energy supply are reduced. In addition, the heat pump device can recycle part of heat in the rectification process and reuse the heat, so that the energy consumption in the rectification process is remarkably reduced, and the energy utilization efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to rectification technical field relates to a propyl alcohol rectification system. BACKGROUND

[0002] In the propyl alcohol rectification process, the crude propyl alcohol in the rectification tower needs to be heated by steam, and the gas phase generated by rectification is generally condensed by air cooler and overhead condenser, and the heat is released into the atmosphere and taken away by circulating water, which causes obvious heat waste. In addition, propyl alcohol heavy component liquid is produced after propyl alcohol rectification, which contains propyl propionate, dimethyl triamyl ketone and other heavy components, and a large amount of propyl alcohol, which has great recycling value.

[0003] At present, the treatment method of crude propyl alcohol in China is to directly use incineration treatment as hazardous waste, which undoubtedly causes great waste of energy. However, the current way of purifying propyl alcohol is usually through rectification tower to recycle propyl alcohol, but this way has low efficiency. The existing patent discloses a method for continuous production of propyl alcohol-carboxylic acid propyl ester azeotropic mixture separation by extraction rectification, which realizes high-purity separation and recovery of propyl alcohol-carboxylic acid propyl ester mixture by using continuous production extraction rectification device, and realizes separation by using the characteristics that the relative volatility of the extractant to propyl alcohol-carboxylic acid propyl ester azeotrope is large. However, this method needs to select a suitable extractant, but it is not easy to find a suitable, efficient and economical solvent, which needs to consider many factors such as solubility, selectivity, boiling point, toxicity and corrosion resistance, and the recovery cost of the extractant is high; the introduction of the extractant in the rectification tower also increases the heat load in the process, resulting in relatively high energy consumption. UTILITY MODEL CONTENTS

[0004] Based on the above-mentioned technical problems to be solved, the purpose of the utility model is to provide a propyl alcohol rectification system.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0006] The utility model provides a propyl alcohol rectification system, which comprises a propyl alcohol rectification tower and a waste liquid rectification tower connected by a propyl alcohol rectification tower bottom pump, wherein,

[0007] The top of the propyl alcohol rectification tower is connected with a heat pump compressor and a propyl alcohol rectification tower top condenser respectively, and the heat pump compressor is further connected with the propyl alcohol rectification tower top condenser through a heat pump separator, a heat pump reboiler and a heat pump condensate tank in sequence;

[0008] The bottom of the propyl alcohol rectification tower is connected with the propyl alcohol rectification tower bottom pump and the heat pump reboiler respectively;

[0009] The top of the waste liquid rectification tower is connected with a waste liquid rectification tower top condenser, a waste liquid rectification tower reflux tank, a vacuum pump and a vacuum exhaust cooler in sequence.

[0010] The waste liquid rectification tower reflux tank is further connected with a waste liquid rectification tower reflux pump, an upper part of the waste liquid rectification tower and an upper part of the propanol rectification tower in sequence.

[0011] Preferably, the gas phase outlet of the heat pump separator is further connected with the inlet of the heat pump compressor.

[0012] Preferably, the propanol rectification tower top condenser is further connected with a propanol rectification tower reflux tank.

[0013] Preferably, the bottom of the propanol rectification tower is further connected with a propanol rectification tower reboiler.

[0014] Preferably, the bottom of the waste liquid rectification tower is connected with a waste liquid rectification tower reboiler and a waste liquid rectification tower bottom pump respectively.

[0015] Preferably, the steam pressure in the waste liquid rectification tower reboiler is 0.5 MPa and the steam temperature is 159℃.

[0016] Preferably, an anti-surge valve is arranged between the gas phase outlet of the heat pump separator and the heat pump compressor.

[0017] Preferably, the top temperature in the propanol rectification tower is 105℃ and the pressure is 0.03 MPa.

[0018] Preferably, when the propanol rectification tower is stabilized at a top temperature of 105℃ and a pressure of 0.03 MPa, the heat pump compressor is started.

[0019] Preferably, the bottom temperature in the waste liquid rectification tower is 97℃, the top temperature is 94℃ and the pressure is -10 kpa.

[0020] The present application has the following advantages:

[0021] (1) The bottom liquid of the propanol rectification tower contains part of propanol and heavy component liquid, which has great recycling value. The part of propanol and heavy component liquid is rectified by the waste liquid rectification tower under negative pressure, so that the propanol can be recycled, and the negative pressure operation can more flexibly adjust the process parameters, adapt to different composition and concentration of propanol waste liquid, and improve the adaptability and operation flexibility of the device.

[0022] (2) Part of the propanol liquid produced by the waste liquid rectification tower enters the stripping section from the middle upper part of the waste liquid rectification tower, so that the light component impurities can be more effectively separated, the energy input required in the stripping section is relatively reduced, and the energy consumption of the rectification process is reduced; the other part is taken out as a product and enters the middle upper part of the propanol rectification tower, so that the propanol rectification tower can recycle propanol.

[0023] (3) The outlet pipeline of the waste liquid rectification column reflux pump is also reserved with an external delivery port, so that the relatively low-purity propanol product can be directly collected, the demand for low-purity propanol in the market is met, and the timeliness and flexibility of product supply are improved.

[0024] (4) The heat pump devices such as the heat pump compressor, the heat pump separator and the heat pump reboiler are introduced into the system, which helps to maintain the stability and reliability of the rectification column operation, reduces the production instability factors caused by energy supply fluctuations. In addition, the heat pump devices can also recover part of the heat in the rectification process and reuse it, thereby significantly reducing the energy consumption of the rectification process and improving the energy utilization efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The structure schematic diagram of the propanol rectification system provided in the application is shown in the figure;

[0026] Symbol representation:

[0027] 1-propanol rectification column, 2-waste liquid rectification column, 3-heat pump compressor, 4-heat pump separator, 5-propanol rectification column overhead condenser, 6-waste liquid rectification column overhead condenser, 7-propanol rectification column reflux tank, 8-waste liquid rectification column reflux tank, 9-vacuum pump, 10-vacuum exhaust cooler, 11-propanol rectification column reboiler, 12-waste liquid rectification column reboiler, 13-heat pump reboiler, 14-heat pump condensate tank, 15-waste liquid rectification column reflux pump, 16-propanol rectification column bottom pump, 17-waste liquid rectification column bottom pump, 18-anti-surge valve. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Please refer to the drawings Figure 1 , the drawings Figure 1 show a propanol rectification system provided in the embodiments of the present application, which comprises a propanol rectification column 1 and a waste liquid rectification column 2 connected by a propanol rectification column bottom pump 16. The propanol rectification column 1 is a component for rectifying crude propanol, and the waste liquid rectification column 2 is a component for rectifying the kettle bottom liquid rectified out of the propanol rectification column 1.

[0030] Specifically, the top of the propanol rectifying column 1 is connected with the heat pump compressor 3 and the propanol rectifying column top condenser 5 respectively, the heat pump compressor 3 is further connected with the propanol rectifying column top condenser 5 through the heat pump separator 4, the heat pump reboiler 13 and the heat pump condensate tank 14 in sequence, and the propanol rectifying column top condenser 5 is further connected with the propanol rectifying column reflux tank 7, and the gas phase outlet of the heat pump separator 4 is further connected with the inlet of the heat pump compressor 3. Meanwhile, the bottom of the propanol rectifying column 1 is connected with the propanol rectifying column bottom pump 16 and the heat pump reboiler 13 respectively. In addition, the bottom of the propanol rectifying column 1 is further connected with the propanol rectifying column reboiler 11.

[0031] Under the conditions of the top temperature of 100℃, the bottom temperature of 106℃ and the pressure of 0.02 Mpa, the propanol rectifying column 1 carries out the rectification treatment on the crude propanol, and the gas phase propanol is obtained at the top and the tower bottom liquid is obtained at the bottom. The gas phase propanol enters the heat pump compressor 3 and the propanol rectifying column top condenser 5 through two pipelines respectively. The propanol rectifying column top condenser 5 carries out the condensation treatment on the gas phase propanol, and the obtained liquid phase propanol enters the propanol rectifying column reflux tank 7 with the temperature of 50℃ and the pressure of 0.015 Mpa. The heat pump compressor 3 carries out the pressurization treatment on the gas phase propanol, and then enters the heat pump separator 4 to protect the heat pump compressor 3 through the heat pump separator 4, wherein the inlet steam amount of the heat pump compressor 3 is 58000 kg / h, and the inlet pressure is 0.115 MPa. The heat pump separator 4 separates out 99.5% liquid phase propanol. The pressurized gas phase propanol enters the heat pump compressor 3 again through the heat pump separator 4 with the temperature of 150℃ and the pressure of 0.35 Mpa for compression; the other part enters the shell inlet of the heat pump reboiler 13 through the heat pump separator 4 to exchange heat with the liquid phase material discharged from the tower bottom of the propanol rectifying column 1. The heat-exchanged gas phase propanol enters the heat pump condensate tank 14 for condensation, and the obtained condensate is 99.5% propanol. The condensate is discharged, and the uncondensed gas phase propanol enters the propanol rectifying column top condenser 5 for condensation treatment, and the obtained liquid phase propanol enters the propanol rectifying column reflux tank 7.

[0032] In the embodiment of the present application, the pipelines between the propanol rectifying column 1 and the heat pump compressor 3 and the propanol rectifying column top condenser 5 are respectively provided with adjusting valves. When the propanol rectifying column 1 runs stably and the top temperature is 105℃ and the pressure is 0.03 MPa, the heat pump compressor 3 is started. The heat pump compressor 3 pressurizes the gas phase propanol to 0.3 MPa and then discharges it into the heat pump separator 4.

[0033] In addition, the gas phase outlet of the heat pump separator 4 and the heat pump compressor 3 are provided with an anti-surge valve 18, so as to re-enter part of the gas phase propanol into the heat pump compressor 3 for compression, so as to adjust the working state of the heat pump compressor 3 and prevent surge.

[0034] The tower bottom liquid containing impurities is obtained from the propanol rectifying column 1, and the tower bottom liquid is discharged through the pipeline with the flow rate of 5 m3 / h of the propyl alcohol rectification tower bottom pump 16 enters the middle of the waste liquid rectification tower 2. The top of the waste liquid rectification tower 2 is connected with the waste liquid rectification tower top condenser 6, the waste liquid rectification tower reflux tank 8, the vacuum pump 9, the vacuum exhaust cooler 10 in sequence, and the waste liquid rectification tower reflux tank 8 is also connected with the waste liquid rectification tower upper part, the propyl alcohol rectification tower upper part in sequence through the waste liquid rectification tower reflux pump 15. The bottom of the waste liquid rectification tower 2 is connected with the waste liquid rectification tower reboiler 12 and the waste liquid rectification tower bottom pump 17 respectively.

[0035] The column still liquid entering the waste liquid rectification tower 2 is subjected to negative pressure rectification treatment under the condition that the column still temperature is 97℃, the top temperature is 94℃, and the pressure is-10kpa, and the top obtains propyl alcohol vapor, and the column still obtains waste liquid. In the embodiment of the present application, the pressure of the waste liquid rectification tower 2 is stabilized at-10kpa, which can reduce the boiling point of propyl alcohol, reduce thermal decomposition and side reactions in the negative pressure rectification process, reduce energy consumption, and improve separation efficiency.

[0036] The propyl alcohol vapor obtained at the top is condensed to 30-40℃ through the waste liquid rectification tower top condenser 6, and the condensed propyl alcohol liquid and uncondensed gas enter the waste liquid rectification tower reflux tank 8 with a temperature of 40℃ and a pressure of-10kpa. The propyl alcohol liquid in the waste liquid rectification tower reflux tank 8 is pumped out by the waste liquid rectification tower reflux pump 15 with a flow rate of 17m 3 / h of the propyl alcohol rectification tower bottom pump 16 enters the middle of the waste liquid rectification tower 2. The top of the waste liquid rectification tower 2 is connected with the waste liquid rectification tower top condenser 6, the waste liquid rectification tower reflux tank 8, the vacuum pump 9, the vacuum exhaust cooler 10 in sequence, and the waste liquid rectification tower reflux tank 8 is also connected with the waste liquid rectification tower upper part, the propyl alcohol rectification tower upper part in sequence through the waste liquid rectification tower reflux pump 15. The bottom of the waste liquid rectification tower 2 is connected with the waste liquid rectification tower reboiler 12 and the waste liquid rectification tower bottom pump 17 respectively.

[0037] The uncondensed gas entering the waste liquid rectification tower reflux tank 8 is pumped out by the vacuum pump 9 with a flow rate of 700m 3 / h into the vacuum exhaust cooler 10. The vacuum exhaust cooler 10 cools the uncondensed gas, and the condensed liquid returns to the waste liquid rectification tower reflux tank 8, and the gas that has not been condensed is incinerated.

[0038] The column still obtained waste liquid is partially pumped into the waste liquid rectification tower reboiler 12, and the other part is pumped into the waste liquid rectification tower bottom pump 17 with a flow rate of 3m 3 / h. The waste liquid rectification tower reboiler 12 is subjected to reboiling treatment under the condition that the steam pressure is 0.5MPa and the steam temperature is 159℃, and then reenters the waste liquid rectification tower 2. The waste liquid entering the waste liquid rectification tower bottom pump 17 is a heavy component, and part of the waste liquid is discharged.

[0039] The working process of the propanol rectification system provided by the embodiments of the present application is as follows:

[0040] S01: The crude propanol is introduced into the propanol rectification column 1, and is subjected to rectification treatment at a column top temperature of 105 DEG C and a pressure of 0.03 MPa. When the propanol rectification column 1 is stable and the column top temperature is 105 DEG C and the pressure is 0.03 MPa, the heat pump compressor 3 is started to make the gaseous propanol produced by rectification enter the heat pump compressor 3 and the propanol rectification column top condenser 5 respectively.

[0041] S02: The heat pump compressor 3 pressurizes the gaseous propanol to 0.3 MPa, and then the gaseous propanol enters the shell side inlet of the heat pump reboiler 13 through the heat pump separator 4, and exchanges heat with the liquid phase material discharged from the column bottom of the propanol rectification column 1. The gaseous propanol after heat exchange enters the heat pump condensate tank 14 for condensation, and the condensate is discharged. The gaseous propanol which is not condensed and the gaseous propanol discharged from the column top of the propanol rectification column 1 are condensed by the propanol rectification column top condenser 5, and the liquid phase propanol formed by condensation is discharged into the propanol rectification column reflux tank 7, wherein the propanol purity of the liquid phase propanol can reach 99.84%.

[0042] S03: The column bottom liquid obtained from the column bottom of the propanol rectification column 1 enters the middle part of the waste liquid rectification column 2 through the propanol rectification column bottom pump 16, and is subjected to negative pressure rectification treatment at a column bottom temperature of 97 DEG C, a column top temperature of 94 DEG C and a pressure of -10 kpa, and propanol vapor is obtained at the column top and waste liquid is obtained at the column bottom.

[0043] S04: The propanol vapor is condensed to 30-40 DEG C by the waste liquid rectification column top condenser 6, and the condensed liquid propanol and the uncondensed gas both enter the waste liquid rectification column reflux tank 8. The liquid propanol in the waste liquid rectification column reflux tank 8 enters the upper part of the waste liquid rectification column 2 through the waste liquid rectification column reflux pump 15, and the other part is taken out as a product to enter the middle and upper part of the propanol rectification column 1, so as to further rectify the propanol rectification column 1 and recover propanol. The uncondensed gas in the waste liquid rectification column reflux tank 8 is pumped to the vacuum exhaust cooler 10 by the vacuum pump 9 at a pressure of -10 kpa. The uncondensed gas is cooled by the vacuum exhaust cooler 10, the condensed liquid returns to the waste liquid rectification column reflux tank 8, and the gas which is still not condensed is incinerated.

[0044] S05: The waste liquid obtained from the column bottom of the waste liquid rectification column 2 is partially introduced into the waste liquid rectification column reboiler 12 at a steam pressure of 0.5 MPa and a steam temperature of 159 DEG C, and is re-introduced into the waste liquid rectification column 2 after reboiling heat exchange; the other part is discharged into the waste liquid rectification column bottom pump 17 and then is discharged.

[0045] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A propanol distillation system, characterized in that, include: The propanol distillation column (1) and the waste liquid distillation column (2) are connected by a bottom pump (16) of the propanol distillation column, wherein, The top of the propanol distillation column (1) is connected to a heat pump compressor (3) and a propanol distillation column top condenser (5). The heat pump compressor (3) is also connected to the propanol distillation column top condenser (5) in sequence through a heat pump separator (4), a heat pump reboiler (13), and a heat pump condensate tank (14). The bottom of the propanol distillation column (1) is connected to the bottom pump (16) of the propanol distillation column and the heat pump reboiler (13). The top of the waste liquid distillation column (2) is connected in sequence to the waste liquid distillation column top condenser (6), the waste liquid distillation column reflux tank (8), the vacuum pump (9), and the vacuum exhaust cooler (10). The waste liquid distillation tower reflux tank (8) is also connected in sequence to the waste liquid distillation tower reflux pump (15), the upper part of the waste liquid distillation tower (2), and the upper part of the propanol distillation tower (1).

2. The propanol distillation system according to claim 1, characterized in that, The gas phase outlet of the heat pump separator (4) is also connected to the inlet of the heat pump compressor (3).

3. The propanol distillation system according to claim 1, characterized in that, The condenser (5) at the top of the propanol distillation column is also connected to the reflux tank (7) of the propanol distillation column.

4. The propanol distillation system according to claim 1, characterized in that, The bottom of the propanol distillation column (1) is also connected to the propanol distillation column reboiler (11).

5. The propanol distillation system according to claim 1, characterized in that, The bottom of the waste liquid distillation column (2) is connected to the waste liquid distillation column reboiler (12) and the waste liquid distillation column bottom pump (17).

6. The propanol distillation system according to claim 5, characterized in that, The steam pressure in the reboiler (12) of the waste liquid distillation tower is 0.5 MPa and the steam temperature is 159°C.

7. The propanol distillation system according to claim 1, characterized in that, An anti-surge valve (18) is provided between the gas phase outlet of the heat pump separator (4) and the heat pump compressor (3).

8. The propanol distillation system according to claim 1, characterized in that, The temperature at the top of the propanol distillation column (1) is 105℃ and the pressure is 0.03MPa.

9. The propanol distillation system according to claim 8, characterized in that, When the propanol distillation column (1) stabilizes at a top temperature of 105°C and a pressure of 0.03 MPa, the heat pump compressor (3) is started.

10. The propanol distillation system according to claim 1, characterized in that, The temperature of the bottom of the waste liquid distillation column (2) is 97°C, the temperature of the top of the column is 94°C, and the pressure is -10 kPa.

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