JP2022056759A - Distillation apparatus - Google Patents

Abstract

To provide a distillation apparatus where a raw material liquid containing a low-boiling point component having a boiling point of 20°C or lower at atmospheric pressure and a high-boiling point component having a boiling point of higher than 40°C at atmospheric pressure is distilled and the high-boiling point component and the low-boiling point component are separated with high energy efficiency.SOLUTION: In the distillation apparatus,: first tower top vapor is cooled in a heat recovery condenser and separated to a first condensate and first vapor; circulation water for the heat recovery condenser is evaporated and steam having a temperature of 102°C or higher and lower than 192°C is generated; the steam is compressed by a vapor compressor and temperature level is increased and supplied to a reboiler as compressed steam having a temperature of 110°C or higher and lower than 200°C and higher than the circulation water for the heat recovery condenser by 8°C or higher and 98°C or lower; and pressure control in a system is performed so as to ensure such conditions that the compressed steam has a temperature of 110°C or higher and lower than 200°C, the steam generated in the heat recovery condenser has a temperature of 102°C or higher and lower than 192°C, the temperature of the compressed steam generated in the heat recovery condenser is higher than the steam by 8°C or higher and 98°C or lower and the temperature of the tower bottom liquid of a first distillation tower is 105°C or higher and 195°C or lower.SELECTED DRAWING: Figure 1

Description

The present invention relates to a distillation apparatus, and more specifically, comprises a raw material liquid containing a low boiling point component having a boiling point of 20 ° C. or lower under atmospheric pressure in a smaller proportion than a high boiling point component having a boiling point of 40 ° C. or higher under atmospheric pressure. The present invention relates to a distillation apparatus for separating a high boiling point component and a low boiling point component by efficiently distilling with energy.

Since the distillation operation normally uses steam, its energy saving has been an issue for many years as a high energy consumption type device.

In recent years, energy-saving distillation that recovers heat from circulating water for capacitors (cooling water) used in capacitors for cooling vapor taken out from the top of a distillation column with a general-purpose heat pump and uses it as a heating source for reboilers. The device is being developed.

However, in many cases, a method of recovering heat from the circulating water for a condenser (cooling water) with a general-purpose heat pump and using it as a heating source for a reboiler cannot always obtain a sufficient energy saving effect.

Recently, a heat recovery condenser is provided in the middle of the distillation tower, and heat is pumped from the cooling water for the heat recovery condenser (cooling water used in the heat recovery condenser to raise the temperature) with a heat pump to reboiler (reboiler). A distillation apparatus has been proposed in which the efficiency of the heat pump is maximized by using it as a heat source for the bottom reboiler (see Patent Document 1).

According to the distillation apparatus of Patent Document 1, it is possible to efficiently operate the heat pump to realize a distillation apparatus having excellent energy saving.

Japanese Patent No. 6612936

By the way, in the distillation apparatus of Patent Document 1, as described above, the cooling water for the heat recovery capacitor (cooling water used in the heat recovery capacitor and raised in temperature) provided in the middle portion of the distillation tower is used as the heat source water. Heat is pumped from this heat source water by a heat pump and used as a heat source for the bottom reboiler. However, when the bottom temperature of the distillation tower rises, the degree of compression of the heat pump increases and the obtained COP (coefficient of performance) becomes small. Become.

Furthermore, when the bottom temperature of the distillation tower rises to nearly 100 ° C, it reaches a temperature that can be used as a heat source for the above-mentioned reboiler (bottom reboiler) in a heat pump that uses cooling water for a heat recovery capacitor as a heat source water. There is a problem that the temperature level cannot be raised and the distillation apparatus cannot be operated properly.

The present invention solves the above-mentioned problems, and is a raw material containing a low boiling point component having a boiling point of 20 ° C. or less under atmospheric pressure in a smaller proportion than a high boiling point component having a boiling point of more than 40 ° C. under atmospheric pressure. It is an object of the present invention to provide a distillation apparatus capable of distilling a liquid efficiently with energy to separate a high boiling point component and a low boiling point component.

In order to solve the above problems, the distillation apparatus of the present invention is used.
A first distillation column for distilling a raw material liquid containing a low boiling point component having a boiling point of 20 ° C. or less under atmospheric pressure in a smaller proportion than a high boiling point component having a boiling point of more than 40 ° C. under atmospheric pressure.
A reboiler for reheating the bottom liquid of the first distillation column having a temperature of 105 ° C. or higher and 195 ° C. or lower.
The first tower top vapor taken out from the top of the first distillation tower is cooled by circulating water for a heat recovery capacitor, and the first condensed liquid and the low boiling point component are contained in a higher proportion than the first condensed liquid. While separating into the first vapor containing the heat recovery capacitor, the circulating water for the heat recovery capacitor is evaporated by the heat energy of the first column top vapor to generate steam having a temperature of 102 ° C. or higher and lower than 192 ° C. With a heat recovery capacitor
The steam having a temperature of 102 ° C. or higher and lower than 192 ° C. generated by the heat recovery capacitor is compressed by electric power to raise the temperature level, and the reboiler has a temperature of 110 ° C. or higher and lower than 200 ° C. and the heat recovery. A steam compressor configured to supply steam as compressed steam with a temperature higher than that of circulating water for capacitors in the range of 8 ° C or higher and 98 ° C or lower.
A second distillation column in which the first vapor, which is a non-condensable component in the heat recovery capacitor, is brought into gas-liquid contact with the following second condensed liquid to be distilled.
A condenser that cools the second tower top vapor taken out from the top of the second distillation column with circulating chiller water for a condenser and separates it into a second condensed liquid and a distillate gas containing the low boiling point component as a main component. When,
A first reflux path for refluxing the first condensed liquid in the heat recovery condenser to the first distillation column as a reflux liquid for the first distillation column.
A second reflux path for refluxing a part of the second condensed liquid in the condenser to the second distillation column as a reflux liquid for the second distillation column is provided.
The temperature of the compressed steam is 110 ° C. or higher and lower than 200 ° C., the temperature of the steam generated by the heat recovery condenser is 102 ° C. or higher and lower than 192 ° C., and the temperature of the compressed steam is the temperature of the steam generated by the heat recovery condenser. In the system, the operating pressure is higher than the temperature in the range of 8 ° C. or higher and 98 ° C. or lower, and the temperature of the bottom liquid of the first distillation column is 105 ° C. or higher and 195 ° C. or lower. It is characterized by being configured to control the pressure of.

In the distillation apparatus of the present invention
The temperature of the compressed steam is 110 ° C or higher and lower than 200 ° C.
The temperature of the circulating water for the heat recovery condenser is 102 ° C or higher and lower than 192 ° C.
The temperature of the compressed steam is higher than the temperature of the steam generated by the heat recovery capacitor in the range of 20 ° C. or higher and 60 ° C. or lower, and
It is preferable that the temperature of the bottom liquid of the first distillation column is 105 ° C. or higher and 195 ° C. or lower.

Further, it is preferable that the concentration of the low boiling point component contained in the raw material liquid supplied to the first distillation column is 0.1 wt% or more and 20 wt% or less.

The distillation apparatus of the present invention is configured as described above, and in the heat recovery condenser, the first column top vapor is cooled by the circulating water for the heat recovery condenser, and the first condensate and the first condensate are more than the first condensate. While separating into the first vapor containing a high proportion of low boiling point components, the circulating water for the heat recovery capacitor is evaporated to generate steam with a temperature of 102 ° C or higher and lower than 192 ° C. The steam generated in the above steam is compressed by electric power to raise the temperature level, and the temperature is in the range of 110 ° C. or higher and lower than 200 ° C. and the temperature is 8 ° C. or higher and 98 ° C. or lower than the circulating water for the heat recovery capacitor. In addition to making it possible to supply as high compressed steam, the temperature of the compressed steam is 110 ° C or higher and lower than 200 ° C, the temperature of the steam generated by the heat recovery capacitor is 102 ° C or higher and lower than 192 ° C, and the temperature of the compressed steam is the heat recovery capacitor. The operating pressure is higher than the temperature of the steam generated in 1 in the range of 8 ° C. or higher and 98 ° C. or lower, and the temperature of the bottom liquid of the first distillation column is 105 ° C. or higher and 195 ° C. or lower. As described above, since the pressure in the system is controlled, the heat recovery capacitor can function as a steam generator such as a boiler, and the generated steam can be used as a general-purpose screw type, for example. By adiabatic compression by the steam compressor of the above, the temperature level is raised to the temperature of the bottom of the column or higher, and it can be effectively used as a heating source in the reboiler of the first distillation column.

That is, in the distillation apparatus of the present invention, the distillation column is provided with a first distillation column and a second distillation column, and the inside of the system of the distillation apparatus is kept in a pressurized state to form a tower of the second distillation column. A heat recovery capacitor for recovering heat from the top vapor of the first distillation column is provided so that the temperature of the top steam becomes a temperature that can be cooled by the chiller water cooled to a predetermined temperature by a general-purpose chiller device. It is arranged so that the circulating water for the heat recovery condenser (cooling water) is heated to a high temperature of 100 ° C. or higher to evaporate the circulating water for the heat recovery condenser (cooling water) and the vaporized steam. (Pressurized steam) is adiabatically compressed with a steam compressor to raise the temperature level and used as a heating source for the distiller. In other words, in the distillation apparatus of the present invention, the heat recovery capacitor functions as a steam generator such as a boiler, and the generated steam is adiabatically compressed by, for example, a general-purpose screw type steam compressor to compress the generated steam to the bottom of the tower. Since the temperature level is raised above the temperature so that it can be effectively used as a heating source in the reboiler of the first distillation column, it becomes possible to perform distillation with high energy saving efficiency.

Further, in the distillation apparatus of the present invention, water condensed by evaporating with a heat recovery condenser, being compressed by a steam compressor and used as a heating source for a reboiler (circulating water for a heat recovery condenser (cooling water)) is used. It is supplied to the heat recovery capacitor and circulated for use as cooling water. In this way, by using water as the heating / cooling medium, the degree of freedom in design, including the degree of freedom in selecting the model of the steam compressor, is improved compared to the case where a hydrocarbon-based substance is used as the heating / cooling medium. , It becomes possible to reduce the manufacturing cost of the distillation apparatus.

Further, in the distillation apparatus of the present invention, since water is used as a heating / cooling medium as described above, low boiling point components and high boiling point components (usually combustible substances such as hydrocarbons) contained in the raw material liquid are used. Compared to the case where the steam of (organic matter) is directly adiabatically compressed (that is, when it is configured as a self-steam compression type distillation apparatus), sparks are generated due to a contact accident of a rotating object such as a turbine blade, and the cause thereof. It is possible to reduce the risk of explosion accidents and improve safety.

Further, since the specific volume (m ³ / kg) of water vapor is smaller than that of hydrocarbon gas and the latent heat of vaporization is about 3 to 5 times larger, the steam compressor can be made smaller. ..

Further, steam used as a heating / cooling medium has a large specific heat and a small super heat as compared with a hydrocarbon gas, and is also excellent as a medium for compressing with a steam compressor to recover heat.

Further, the water condensed by the reboiler is sent to the heat recovery condenser again and becomes steam, resulting in infinite circulation of water. In this way, by using water as a heating / cooling medium, the degree of freedom in selecting the steam compressor is increased, and it becomes possible to reduce the equipment cost.

In the present invention, the first distillation column top vapor, which is the top vapor of the first distillation column, is guided to a heat recovery capacitor to recover heat. However, the first distillation column and the second distillation column are combined into one distillation. It is also possible to extract the vapor from the position between the first distillation column and the second distillation column (intermediate part of the distillation column) in the case of being configured as a column and guide it to the heat recovery capacitor.

In the present invention, the raw material liquid is limited to the raw material liquid in which the ratio of the low boiling point component is smaller than the ratio of the high boiling point component, because the ratio of the low boiling point component is smaller than the ratio of the high boiling point component. In distillation with the raw material liquid, the heat demand in the distillation tower is concentrated in the recovery section, so a heat recovery capacitor is added to the intermediate stage and the circulation is reduced to reduce the amount of return in the condenser at the top of the column. This is because the power can be reduced and the steam generated by the heat recovery capacitor can be adiabatically compressed by a steam compressor to be used as a heating source for the reboiler. On the contrary, in the case of the raw material liquid in which the ratio of the low boiling point component is larger than the ratio of the high boiling point component, the heat demand in the distillation column is concentrated in the concentrated portion, so that the present invention cannot be applied.
In the present invention, the energy saving effect becomes higher as the ratio of the low boiling point component of the raw material liquid is smaller than the ratio of the high boiling point component.

Further, the temperature of the compressed steam is 110 ° C. or higher and lower than 200 ° C., the temperature of the circulating water for the heat recovery condenser is 102 ° C. or higher and lower than 192 ° C., and the temperature of the compressed steam is 20 ° C. higher than the temperature of the steam generated by the heat recovery condenser. When the temperature is high in the range of 60 ° C. or lower and the temperature of the bottom liquid of the first distillation tower is 105 ° C. or higher and 195 ° C. or lower, the addition to the steam compressor is further reduced to further save energy. It is possible to provide a distillation apparatus having excellent properties.

Further, when the concentration of the low boiling point component contained in the raw material liquid supplied to the first distillation column is configured to be 0.1 wt% or more and 20 wt% or less, distillation is further performed with energy efficiency to obtain the high boiling point component. It becomes possible to realize a distillation apparatus capable of efficiently separating low boiling point components.

It is a flow sheet which shows the structure of the distillation apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be shown, and the features of the present invention will be described in more detail.

In this embodiment, a distillation apparatus for separating a raw material liquid containing 2 wt% of propane, which is a low boiling point component, and 98 wt% of benzene, which is a high boiling point component, to separate propane and benzene will be described as an example.

The distillation apparatus 100 according to the present embodiment is a distillation apparatus for which energy saving is improved by using a thermal compressor.

As shown in FIG. 1, the distillation apparatus 100 according to the present embodiment has a high boiling point of 2 wt% of propane, which is a low boiling point component having a boiling point of −42 ° C. under atmospheric pressure, and a boiling point of 80.1 ° C. under atmospheric pressure. It includes a first distillation column 1 for distilling a raw material liquid (supply liquid) containing 98 wt% of benzene as a component, and a reboiler 1a for reheating the bottom liquid of the first distillation tower. In this embodiment, a bubble tower is used as the first distillation column 1.

Further, in the distillation apparatus 100 according to the present embodiment, a liquid film drop type heat exchanger is used as the reboiler 1a.

In the distillation apparatus 100 according to the present embodiment, the raw material liquid is preheated to 150 ° C. by exchanging heat with the bottom liquid (163 ° C.) of the first distillation column in the preheater 41, and then the first distillation column. It is configured to be supplied to 1. As the preheater 41, a multi-tube heat exchanger is used.

Further, the distillation apparatus 100 according to the present embodiment is a heat recovery capacitor 11 that cools the first column top vapor at 123 ° C. taken out from the top of the first distillation column 1 with circulating water (cooling water) for a heat recovery capacitor. Is equipped with.

The heat recovery condenser 11 cools the first tower top vapor (123 ° C.) with circulating water (cooling water) for the heat recovery condenser, and cools the first condensed liquid and propane, which is a lower boiling point component than the first condensed liquid. Is separated into the first vapor containing a high proportion of water, and the circulating water for the heat recovery capacitor is evaporated by the heat energy of the first column top vapor so that steam having a temperature of 119 ° C can be generated. Has been done.

In the distillation apparatus 100 according to the present embodiment, a liquid film drop type heat exchanger is used as the heat recovery capacitor 11.

The first condensed liquid in the heat recovery condenser 11 is configured to be returned to the top of the first distillation column 1 as a reflux liquid for the first distillation column through the first reflux path 31.

Further, the distillation apparatus 100 includes a steam compressor 20 that uses electric power to compress steam having a temperature of 102 ° C. or higher and lower than 192 ° C. (119 ° C. in this embodiment) generated by the heat recovery condenser 11.

The steam compressor 20 raises the temperature level of the steam having a temperature of 102 ° C. or higher and lower than 192 ° C. (119 ° C. in the present embodiment) generated by the heat recovery condenser 11 described above, and heats the reboiler 1a. Is 110 ° C. or higher and lower than 200 ° C. (167 ° C. in the present embodiment), and the temperature is higher than the circulating water for the heat recovery compressor in the range of 8 ° C. or higher and 98 ° C. or lower (167 ° C.-119 ° C. = 48 in the present embodiment). It is configured to be able to be supplied as compressed steam (high ° C).

As the steam compressor 20, a general-purpose screw type steam compressor is used. As described above, the distillation apparatus 100 of the present embodiment is configured so that the temperature rise range is 48 ° C., which is not so large, and it is not necessary to increase the degree of compression so much. Therefore, a general-purpose screw type steam compressor. Can be used, and an increase in equipment cost can be suppressed.

When the temperature of the compressed steam is configured to be higher in the range of 20 ° C. or higher and 60 ° C. or lower than the temperature of the steam generated by the heat recovery condenser 11, the addition to the steam compressor 20 is further reduced. , It is possible to provide a distillation apparatus having more excellent energy saving.

The steam generated by the heat recovery capacitor 11 is configured to be supplied to the steam compressor 20 via the separator 21.

Further, the reboiler 1a is configured to supply steam having a temperature of 167 ° C. or higher as auxiliary steam.

Further, the distillation apparatus 100 takes out the first vapor, which is the non-condensed component in the heat recovery condenser 11, from the second distillation column 2 and the top of the second distillation column 2, at a temperature of 21.7 ° C. The second column top vapor is cooled by the circulating chiller water for a capacitor having a temperature of 7.4 ° C. cooled by the chiller unit 55, and contains the second condensed liquid and propane (low boiling point component) as main components. It is provided with a condenser 22 that separates into distillate gas.

In the present embodiment, as the second distillation column 2, a bubble tower is adopted as in the first distillation column 1.
As the capacitor 22, a multi-tube heat exchanger is used.

Further, the entire amount of the second condensed liquid condensed by the condenser 22 is returned to the top of the second distillation column 2 through the second reflux path 32.

Further, the circulating chiller water for the condenser used in the condenser 22 and whose temperature has risen to 12.4 ° C. is returned to the chiller unit 55, cooled to 7.4 ° C., and circulated to the condenser 22 again.

In this distillation apparatus 100, the temperature of the compressed steam compressed by the above-mentioned steam compressor 20 is 110 ° C. or higher and lower than 200 ° C. (167 ° C. in this embodiment), and the temperature of the steam generated by the heat recovery condenser 11 Is 102 ° C. or higher and lower than 192 ° C. (119 ° C. in the present embodiment), and the temperature of the compressed steam is higher than the temperature of the steam generated by the heat recovery capacitor 11 in the range of 8 ° C. or higher and 98 ° C. or lower (167 ° C. in the present embodiment). Operating pressure (the present embodiment) that ensures the condition that the temperature of the bottom liquid of the first distillation column 1 is 105 ° C. or higher and 195 ° C. or lower (163 ° C. in the present embodiment). The pressure in the system can be controlled so as to be 0.63 MPa).

That is, in the present embodiment, the pressure adjusting valve 60 is provided in the line for cooling with the condenser 22 and taking out the distillate gas at 15.4 ° C., so that the pressure in the system is maintained at 0.63 MPa. It is configured in.

In this embodiment, a raw material liquid supply pump for supplying the raw material liquid via the preheater 41 is provided in the system of the distillation apparatus 100 whose pressure is adjusted so as to be in a pressurized state of 0.63 MPa. However, in FIG. 1, the illustration of the raw material liquid supply pump is omitted.

However, when the raw material liquid is supplied from the previous process operated under a pressure of 0.63 MPa or more, it is not necessary to provide a raw material liquid supply pump.

In the distillation apparatus 100 configured as described above, a raw material liquid having a temperature of 100 ° C. containing 98 wt% of benzene, which is a high boiling point component, and 2 wt% of propane, which is a low boiling point component, is contained at a rate of 50,000 kg / h. It is supplied to the first distillation column 1 in a state of being preheated to 150 ° C. via the preheater 41.

Then, from the bottom of the first distillation column, a canned liquid having a temperature of 163 ° C. containing 99.99999 wt% of benzene, which is a high boiling point component, and 0.0001 wt% of propane, which is a low boiling point component, is 49000 kg / h. Collected at a rate.

Further, as the non-condensable gas that was not condensed by the condenser 22 that cools the second column top vapor of the second distillation column 2, the distillate gas having a temperature of 15.4 ° C. and a pressure of 0.63 MPa was 1000 kg / h. Collected at a rate. The distillate gas contains 0.01 wt% of benzene, which is a high boiling point component, and 99.99 wt% of propane, which is a low boiling point component.

Next, the features of the distillation apparatus 100 according to the present embodiment will be described in more detail.
The raw material liquid (a mixed liquid of 98 wt% benzene and 2 wt% propane) in the present embodiment is distilled at atmospheric pressure to obtain 99.99 wt% propane and 0.01 wt% benzene in the gas composition at the top of the tower, and the liquid composition at the bottom of the tower becomes 99.99 wt% propane and 0.01 wt% benzene. Considering the case of distilling to 0.0001 wt% propane and 99.99999 wt% benzene, if pressure loss is not taken into consideration, the column top temperature is about -42 ° C (boiling point of propane) and the column bottom temperature is about 80.1. It becomes ℃ (boiling point of benzene), the temperature difference becomes 122.1 ℃, and the temperature at the top of the column is too low, which is difficult to realize as an actual distillation apparatus.

On the other hand, when the operating pressure (internal pressure) of the distillation column is set to, for example, 0.63 MPa (pressurization), the column top temperature (top temperature of the second distillation column 2) is 21.7 ° C., which is a general-purpose chiller. Since it can be cooled with water, it can be realized as a practical distillation apparatus. The bottom temperature (top temperature of the first distillation column 1) under this condition (0.63 MPa) is 163 ° C.

Based on this idea, in the distillation apparatus 100 according to the present embodiment, the operating pressure (internal pressure) is set to 0.63 MPa.

Then, as described in the above embodiment, the design conditions are as follows.

(1) Design conditions (1-1) Raw material liquid (supply liquid) composition High boiling point component: Benzene 98 wt%
Low boiling point component: Propane 2 wt%
(1-2) Raw material liquid (supply liquid) Supply amount: 50,000 kg / h
(1-3) Operating pressure (internal pressure): 0.63 MPa
(1-4) Raw material liquid supply temperature to the first distillation column: 150 ° C.
(1-5) Distillate gas (distilled gas from the second distillation column) Composition Low boiling point component: Propane 99.99 wt%
High boiling point component: Benzene 0.01 wt%
(1-6) Composition of canned liquid (first distillation column bottom liquid) High boiling point component: benzene 99.99999 wt%
Low boiling point component: Propane 0.0001 wt%

(2) Next, the energy saving property of the distillation apparatus according to the above embodiment will be examined.
Here, in order to confirm the energy saving effect, the energy consumption of each of the "conventional steam type distillation apparatus" that uses the steam generated by the boiler as energy and the above-mentioned "distillation apparatus 100 according to the present embodiment" is obtained. rice field.
The energy consumption was calculated and evaluated in terms of primary energy.

(2-1) Energy consumption of conventional steam type distillation equipment ・ Steam heating amount: 1100kW
・ Chiller power: 135.9kW
・ Primary energy (converted as primary energy conversion coefficient: 2.57)
・ Primary energy = 1100kW + 135.9kW × 2.57
= 1449.3kW
(2-2) Energy consumption of distillation apparatus according to the embodiment of the present invention-Steam heating amount: 336.2 kW
・ Steam compressor power: 130.4kW
・ Chiller power: 20.8kW
・ Primary energy (converted as primary energy conversion coefficient: 2.57)
Primary energy = 336.2 kW + (130.4 + 20.8) kW x 2.57 = 724.8 kW

As described above, the energy consumption in terms of primary energy in the "conventional steam type distillation apparatus" is 1449.3 kW, whereas in the "distillation apparatus 100 according to the present embodiment", 724. It will be 8 kW.
Therefore, the primary energy reduction rate is
{(1449.3-724.8) /1449.3} × 100 = 50.0%
Therefore, according to the "distillation apparatus 100 according to the present embodiment", it can be seen that the energy consumption can be reduced to half of the energy consumption of the "conventional steam type distillation apparatus".

Next, although there are some overlaps with the above description, the characteristic configuration of the distillation apparatus 100 according to the present embodiment will be summarized and described.

As described above, the distillation apparatus 100 according to the present embodiment is configured as a two-column type distillation apparatus in which the distillation column is separated into two distillation columns, a first distillation column 1 and a second distillation column 2. ..

Then, the top vapor of the first distillation column 1 (first top vapor) is sent to the heat recovery condenser 11 and cooled by the circulating liquid for the heat recovery condenser, and the condensed liquid (first condensed liquid) is the first. It is refluxed to the top of the distillation column 1.

On the other hand, the circulating fluid (a part of the cooling water) for the heat recovery capacitor evaporates due to the heat energy of the first tower top vapor and is sent to the steam compressor 20. Therefore, the heat recovery capacitor 11 functions as a steam generator when viewed from the heat recovery steam side.

The temperature of the first tower top vapor supplied to the heat recovery capacitor 11 is 123 ° C., and the temperature of the steam generated by the heat recovery capacitor 11 is 119 ° C.

Both steam 777.8 kW supplied from the steam compressor 20 and steam 336.2 kW (535 kg / h) supplied as auxiliary steam (utility) are used for heating the reboiler 1a, and the total calorific value is total. Is 1114 kW.

The amount of heat recovered by the heat recovery condenser is 625 kW, while the amount of heat of the steam supplied from the steam compressor 20 is as large as 777.8 kW. This is because the desuperheat water is supplied and the condensed water in the reboiler is sent to the separator by a drain pump to recover the heat (see FIG. 1).

The steam drain condensed by the reboiler 1a is supplied to the separator 21 again and becomes steam.

In the distillation apparatus 100 according to the present embodiment, as shown in FIG. 1, the amount of heat supplied to the reboiler 1a as auxiliary steam becomes excessive, so that a predetermined amount of drain from the heat recovery condenser circulation pump goes out of the system. It is configured to balance the heat balance by being discharged.

Further, the condensed liquid (first condensed liquid) of the first column top vapor condensed by the heat recovery condenser 11 returns to the first distillation column 1 as a reflux liquid, and the 219.8 kW vapor that was not condensed by the heat recovery condenser 11 is , Will be sent to the bottom of the second distillation column 2 and supplied for distillation in the second distillation column 2.

Further, the top vapor of the second distillation column 2 is sent to the condenser 22, and the entire amount of the liquid condensed by the condenser 22 is returned to the second distillation column as a reflux liquid for the second distillation column.

Here, the amount of heat supplied to the first distillation column 1 is 844.8 kW, whereas the amount of heat supplied to the second distillation column 2 is the remaining amount of heat 219.8 kW condensed by the heat recovery capacitor 11. Become. Therefore, the amount of gas and liquid passing through the second distillation column 2 becomes smaller than the amount of gas and liquid passing through the first distillation column 1, and the second distillation column 2 can be miniaturized. Specifically, the diameter of the second distillation column 2 can be reduced to about half that of the first distillation column 1, and the equipment can be downsized and the equipment cost can be reduced.

The vapor that was not condensed by the condenser 22 was extracted as a distillate gas (refined gas) containing 99.99 wt% propane and 0.01 wt% benzene at a pressure of 0.63 MPa at a rate of 1000 kg / h. , Will be collected.

On the other hand, the bottom liquid of the first distillation column 1 is withdrawn from the can drain pump as a can drain containing 99.99999 wt% benzene and 0.0001 wt% propane, and is recovered.

The distillation apparatus 100 according to the present embodiment is configured as described above, and as a result, a raw material liquid containing a predetermined low boiling point component and a high boiling point component is energy-efficiently distilled to obtain a high boiling point component. It can be separated from low boiling point components.

In the distillation apparatus 100 according to the present embodiment, a foam column is adopted as the first distillation column 1 and the second distillation column 2, but the configuration of the first distillation column 1 and the second distillation column 2 is special. It is also possible to adopt other types of distillation columns, such as a filling column using an irregular filling.

Further, in the distillation apparatus 100 according to the present embodiment, a liquid film drop type heat exchanger is used for the reboiler 1a and the heat recovery condenser 11, but in the distillation apparatus of the present invention, the reboiler 1a and the heat recovery condenser 11 are used. There are no particular restrictions on the configuration of the above, and other types of heat exchangers can be used.

Further, in the distillation apparatus 100 according to the present embodiment, a multi-tube heat exchanger is used for the condenser 22 and the preheater 41, but in the distillation apparatus of the present invention, the configuration of the condenser 22 and the preheater 41 is special. It is also possible to use other types of heat exchangers without any restrictions.

Further, in the distillation apparatus 100 according to the present embodiment, a general-purpose screw type steam compressor is adopted as the steam compressor 20 to suppress an increase in equipment cost, but another steam compressor 20 is used. It is also possible to use a steam compressor of the type.

Further, in the above embodiment, the case where the raw material liquid contains benzene as a high boiling point component and propane as a low boiling point component has been described as an example, but the raw material liquid is not limited to this, and the high boiling point component is toluene. , Xylene, etc., and the present invention can be applied even when the low boiling point component is butane, propylene, or the like.

The present invention is not limited to the above embodiment in other respects as well, and applications and modifications can be added within the scope of the invention.

1 1st distillation tower 2 2nd distillation tower 1a Revoira 11 Heat recovery condenser 20 Steam compressor 21 Separator 22 Condenser 31 1st reflux path for refluxing the condensed liquid of the heat recovery condenser to the 1st distillation tower 32 The condensed liquid of the condenser is the first 2 Second reflux path to return to the distillation column 41 Preheater 55 Chiller unit 60 Pressure control valve 100 Distiller

Claims (3)

A first distillation column for distilling a raw material liquid containing a low boiling point component having a boiling point of 20 ° C. or less under atmospheric pressure in a smaller proportion than a high boiling point component having a boiling point of more than 40 ° C. under atmospheric pressure.
A reboiler for reheating the bottom liquid of the first distillation column having a temperature of 105 ° C. or higher and 195 ° C. or lower.
The first tower top vapor taken out from the top of the first distillation tower is cooled by circulating water for a heat recovery capacitor, and the first condensed liquid and the low boiling point component are contained in a higher proportion than the first condensed liquid. While separating into the first vapor containing the heat recovery capacitor, the circulating water for the heat recovery capacitor is evaporated by the heat energy of the first column top vapor to generate steam having a temperature of 102 ° C. or higher and lower than 192 ° C. With a heat recovery capacitor
The steam having a temperature of 102 ° C. or higher and lower than 192 ° C. generated by the heat recovery capacitor is compressed by electric power to raise the temperature level, and the reboiler has a temperature of 110 ° C. or higher and lower than 200 ° C. and the heat recovery. A steam compressor configured to supply steam as compressed steam with a temperature higher than that of circulating water for capacitors in the range of 8 ° C or higher and 98 ° C or lower.
A second distillation column in which the first vapor, which is a non-condensable component in the heat recovery capacitor, is brought into gas-liquid contact with the following second condensed liquid to be distilled.
A condenser that cools the second tower top vapor taken out from the top of the second distillation column with circulating chiller water for a condenser and separates it into a second condensed liquid and a distillate gas containing the low boiling point component as a main component. When,
A first reflux path for refluxing the first condensed liquid in the heat recovery condenser to the first distillation column as a reflux liquid for the first distillation column.
A second reflux path for refluxing a part of the second condensed liquid in the condenser to the second distillation column as a reflux liquid for the second distillation column is provided.
The temperature of the compressed steam is 110 ° C. or higher and lower than 200 ° C., the temperature of the steam generated by the heat recovery condenser is 102 ° C. or higher and lower than 192 ° C., and the temperature of the compressed steam is the temperature of the steam generated by the heat recovery condenser. In the system, the operating pressure is higher than the temperature in the range of 8 ° C. or higher and 98 ° C. or lower, and the temperature of the bottom liquid of the first distillation tower is 105 ° C. or higher and 195 ° C. or lower. A distillation apparatus characterized in that it is configured to be pressure controlled. The temperature of the compressed steam is 110 ° C or higher and lower than 200 ° C.
The temperature of the circulating water for the heat recovery condenser is 102 ° C or higher and lower than 192 ° C.
The temperature of the compressed steam is higher than the temperature of the steam generated by the heat recovery capacitor in the range of 20 ° C. or higher and 60 ° C. or lower, and
The distillation apparatus according to claim 1, wherein the temperature of the bottom liquid of the first distillation column is 105 ° C. or higher and 195 ° C. or lower. The distillation apparatus according to claim 1 or 2, wherein the concentration of the low boiling point component contained in the raw material liquid supplied to the first distillation column is 0.1 wt% or more and 20 wt% or less.

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