JP2015192933A - Distillation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide distillation equipment capable of efficiently improving the heat energy of the whole factory equipment.SOLUTION: Distillation equipment 1 comprises: a distillation tower 2 dividing the components contained in a raw material into each fraction; a reflux facility 3 which has a reflux condenser 12 for liquefying the gaseous light fraction taken out from the tower top 2b of the distillation tower 2 to obtain a liquid light fraction, and returns a part of the liquid light fraction to the distillation tower 2; and a cooling water-feeding unit 4 feeding a cooling water to the condenser 12. The cooling water-feeding unit 4 has an evaporation cooling part 17 which is disposed near the reflux facility 3, decides the heat quantity to be taken from the cooling water at the evaporation of a refrigerant solution corresponding to the concentration of ammonia in the refrigerant solution, and feeds the cooled water to the condenser 12, and a refrigerant solution-feeding part 16 which is disposed near a heat supply source S and feeds to the evaporation cooling part 17, the refrigerant solution adjusted to a prescribed concentration by utilizing the water vapor supplied from the heat supply source S.

Description

  The present invention relates to a distillation facility.

  Patent Document 1 describes a steam turbine using steam. The steam turbine rotates an internal turbine by steam sucked from the steam inlet, and outputs the rotational force from an output shaft connected to the coupling. Patent Document 2 describes a rapid starter for a steam turbine. This rapid start-up device is for supplying water into the reactor by rapid start-up for safety of the reactor due to lowering of the water level in the reactor.

JP 2012-21410 A Japanese Utility Model Publication No. 54-064848

  By the way, a technique for reusing waste heat from a factory or the like as a heat source to improve the energy efficiency of the entire factory equipment has been studied. For example, there is a form in which heat is discharged as steam in the form of exhaust heat exhausted from a factory, and when the thermodynamic potential such as temperature and pressure is low, it is difficult to reuse as a heat source for recovering energy It was a situation. In recent years, the steam turbine has been changed from a steam turbine to a highly reliable motor turbine as a power source for rotating equipment, which spurred the case where steam with low thermodynamic potential such as temperature and pressure is discharged to the outside. It was difficult to efficiently use the thermal energy of the entire factory equipment.

  Then, an object of this invention is to provide the distillation equipment which can utilize the thermal energy of the whole factory equipment efficiently.

  A distillation facility according to one aspect of the present invention includes a distillation column that separates each fraction using a difference in boiling points of components contained in a raw material, and a gaseous light fraction taken from the top of the distillation column. A condensing unit for liquefying to obtain a liquid light fraction, a reflux unit for returning a part of the liquefied light fraction to the distillation tower, and a cooling water supply unit for supplying cooling water to the condensing unit The cooling water supply unit is disposed in the vicinity of the reflux unit, and the amount of heat taken from the cooling water when the refrigerant solution evaporates is determined in accordance with the refrigerant concentration of the refrigerant solution including the refrigerant having a vapor pressure higher than that of water. An evaporative cooling unit that supplies cooling water cooled to the condensing unit, and a refrigerant solution that is disposed in the vicinity of the heat supply source and that has a predetermined concentration using a heat medium supplied from the heat supply source A refrigerant solution supply unit that supplies the cooling unit.

  This distillation facility has a reflux part, and cools the gaseous light fraction in the condensing part of the reflux part to obtain a liquid light fraction. Here, cooling water is used for cooling the gaseous light fraction. And this cooling water is supplied from the cooling water supply part using the refrigerant | coolant solution containing the refrigerant | coolant whose vapor pressure is larger than water. Since the vapor pressure of the refrigerant is higher than that of water, it is possible to use a low-pressure / low-temperature exhaust heat source that has been difficult to use in the past to form cooling water. Therefore, it becomes possible to use relatively low-pressure and low-temperature steam as a heat source, so that the thermal energy of the entire factory equipment can be used efficiently. Moreover, since the evaporative cooling part of the cooling water supply part is disposed in the vicinity of the recirculation part, it is possible to shorten the transport piping from the evaporative cooling part to the recirculation part. Accordingly, the influence of the external environment such as the atmospheric temperature on the cooling water can be suppressed. Furthermore, since the ammonia concentration of the refrigerant solution corresponds to the amount of heat taken from the cooling water, the cooling capacity of the cooling water supply unit is hardly affected by the atmospheric temperature. Therefore, it is possible to easily obtain cooling water having a stable water temperature.

  The distillation facility further includes a pressure control unit that controls the internal pressure at the top of the column, and the pressure control unit acquires the internal pressure at the top of the column and liquefies it back to the distillation column using the value of the internal pressure. The temperature of the light fraction is calculated, the temperature of the cooling water is calculated using the temperature of the light fraction, and the circulation amount of the refrigerant solution is calculated using the temperature of the cooling water. According to this pressure control unit, it is possible to calculate the circulation amount of the refrigerant solution necessary for controlling to a predetermined tower top pressure even when the tower top pressure fluctuates. Therefore, the tower top pressure can be easily controlled.

  The heat medium is water vapor of 0.1 MPa or more and 0.2 MPa or less and 100 ° C. or more and 160 ° C. or less. Such a heat medium is a heat medium having an energy range that has not been conventionally used. Therefore, since the heat medium that has been discarded conventionally can be used as a recovery heat source, the energy efficiency of the entire factory including the distillation equipment can be increased.

  ADVANTAGE OF THE INVENTION According to this invention, the distillation installation which can utilize efficiently the thermal energy of the whole factory installation is provided.

FIG. 1 is a diagram schematically illustrating a distillation facility according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the operation of the cooling water supply device.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 1, a distillation facility 1 includes a distillation column 2, a reflux facility (refluxing unit) 3, a cooling water supply device (cooling water supply unit) 4, a pressure control device (pressure control unit) 6, It is equipped with.

  The distillation column 2 separates each fraction using the difference in boiling point of components contained in the raw material. Specifically, the raw material such as crude oil is boiled by heating and the difference in boiling point is used to produce crude oil. The raw material is continuously separated into predetermined fractions from a light part to a heavy part. The distillation tower 2 has a cylindrical tower body 2a, a tower top 2b provided at the upper end of the tower body 2a, and a tower bottom 2c provided at the lower end of the tower body 2a.

  The tower main body 2a has a plurality of trays (not shown) arranged in the vertical direction at predetermined intervals therein, a supply port 7 for supplying crude oil to the distillation tower 2, and a tower main body outlet 9. doing. In the tray, the crude oil vapor rising from the lower part comes into contact with the liquid on the tray, and mass transfer and heat exchange are performed. And the oil of the target property is obtained by extracting a liquid from the tower top part 2b, the tower bottom part 2c, or the tray of predetermined temperature. The supply port 7 is arrange | positioned in the approximate center in the up-down direction of the tower main-body part 2a. From the tower top outlet 8, for example, a light fraction such as LPG or naphtha is taken out. Further, for example, a kerosene fraction or a light oil fraction is taken out from the tower main body outlet 9. Further, a heavy fraction that is residual oil is taken out from the tower bottom outlet 11.

  The reflux facility 3 condenses the light fraction taken out from the tower top outlet 8 of the distillation column 2, returns a part of it as reflux to the distillation column 2, and the remainder as a product as a processing device (not used in the next step). Send to the figure. The reflux facility 3 guides the light fraction from the tower top outlet 8 to the reflux condenser 12 and the reflux condenser (condenser) 12 for condensing the light fraction taken out from the tower top 2b of the distillation column 2 as steam. It has an introduction pipe 13 and a lead-out pipe 14 for sending the light fraction liquefied by the reflux condenser 12 to the distillation column 2 or the processing device for the next step.

  The reflux condenser 12 is a heat exchanger that cools and condenses (liquefies) the light fraction taken out from the tower top 2b as steam. The reflux condenser 12 of this embodiment is a so-called water-cooled condenser. In the reflux condenser 12, a gaseous light fraction is introduced around the cooling pipe through which the cooling water flows, and heat exchange is performed between the light fraction and the cooling water. Therefore, the reflux condenser 12 is supplied with a predetermined flow of cooling water at a predetermined temperature.

  The cooling water supply device 4 cools cooling water to be supplied to the reflux condenser 12 using a refrigeration cycle of a so-called absorption refrigerator. As shown in FIG. 2, the cooling water supply device 4 has a total of four heat exchangers: a regenerator G, a condenser C, an evaporator E, and an absorber A. These heat exchangers are respectively connected by transport pipes L1 to L5, and a refrigerant solution containing a refrigerant and an absorbing liquid is accommodated therein. The cooling water supply device 4 uses a refrigerant solution in which the absorbing liquid is water and the refrigerant is ammonia. The inside of the regenerator G and the condenser C is in a high pressure state. On the other hand, the inside of the evaporator E and the absorber A is lower than the internal pressure of the regenerator G and the condenser C.

  Here, the cooling water supply device 4 of the present embodiment includes a refrigerant solution supply unit 16 and an evaporative cooling unit 17. The refrigerant solution supply unit 16 supplies the refrigerant solution M3 having a predetermined concentration to the evaporative cooling unit 17 using water vapor supplied from the heat supply source S. That is, the refrigerant solution supply unit 16 includes a regenerator G and a condenser C that constitute an absorption refrigerator.

  On the other hand, the evaporative cooling unit 17 is arranged in the vicinity of the heat supply source S and supplies the refrigerant solution M3 having a predetermined concentration to the evaporative cooling unit 17 using water vapor supplied from the heat supply source S. It is. In other words, the evaporative cooling unit 17 is disposed in the vicinity of the reflux facility 3, and the amount of heat taken from the cooling water when the refrigerant solution M3 evaporates is determined corresponding to the ammonia concentration of the refrigerant solution M3. Cooled cooling water is supplied. Therefore, the evaporative cooling unit 17 includes the evaporator E and the absorber A that constitute the absorption refrigerator.

  The refrigeration cycle of the cooling water supply device 4 will be described. First, a heat medium of about 80 ° C. to 150 ° C. is put into the regenerator G. As this heat medium, steam supplied from the heat supply source S to the regenerator G is used. Due to this heat, ammonia in the refrigerant solution evaporates in the regenerator G having a pressure of 1.0 MPa to 1.5 MPa, and refrigerant vapor M2 and a weak refrigerant solution M1 having a low refrigerant concentration are generated. The refrigerant vapor M2 is sent to the condenser C through the transport pipe L1. Inside the condenser C, the refrigerant vapor M2 is cooled by the cooling water, and the refrigerant vapor M2 is liquefied and changed into the refrigerant solution M3. For example, the inside of the condenser C is set to an environment of about 40 to 80 ° C. and 1.0 to 1.5 MPa. The refrigerant solution M3 is sent from the high-pressure side condenser C to the low-pressure side evaporator E through the transport pipe L2.

  The refrigerant solution M3 sent to the evaporator E evaporates inside the evaporator E and changes to refrigerant vapor M4. For example, the inside of the evaporator E is set to an environment of about 3 to 10 ° C. and 0.1 to 0.5 MPa. At this time, cooling water of 10 ° C. to 30 ° C., for example, 20 ° C. is fed into the cooling pipe LW of the evaporator E. While the cooling water flows through the cooling pipe LW, the cooling water is cooled by taking the energy of the latent heat of vaporization of the refrigerant solution M3. This cooled water is supplied to the reflux condenser 12. On the other hand, the refrigerant vapor M4 in the evaporator E is sent to the absorber A through the transport pipe L3. The absorber A is further fed with the refrigerant weak solution M1 from the regenerator G. Therefore, the refrigerant vapor M4 and the refrigerant weak solution M1 are mixed inside the absorber A, and the refrigerant strong solution M5 having a high refrigerant concentration is generated. The strong refrigerant solution M5 is fed into the regenerator G through a pump.

  As shown in FIG. 1, the pressure control device 6 controls the concentration for controlling the internal pressure in the distillation column 2. For example, when the internal pressure of the distillation column 2 becomes high, the pressure control device 6 reduces the temperature of the liquid light fraction supplied from the reflux facility 3 to the distillation column 2, for example, There is a control method.

  Specifically, the pressure control device 6 acquires the internal pressure of the tower top 2b using the pressure sensor P provided at the tower top 2b. Subsequently, the pressure control device 6 determines whether the value of the obtained internal pressure is within a preset specified range or outside the specified range. If the internal pressure is outside the specified range, the temperature of the liquid light fraction charged from the reflux condenser 12 to the distillation column 2 is adjusted to control the internal pressure. Here, the temperature of the liquid light fraction is controlled by the temperature of the cooling water supplied to the reflux condenser 12. The temperature of the cooling water is controlled by the circulation amount of the refrigerant solution fed into the evaporator E of the cooling water supply device 4. Therefore, the pressure control device 6 calculates the temperature of the cooling water supplied to the reflux condenser 12 from the temperature of the liquid light fraction to be sent into the distillation column 2. And the circulation amount of a refrigerant | coolant solution is controlled by adjusting the quantity of the waste heat amount supplied to the regenerator G so that it may become predetermined | prescribed cooling water temperature.

  Here, conventionally, when the temperature of the distillation column is controlled, the amount of cooling water supplied to the reflux condenser is adjusted. However, since the temperature of the cooling water depends on the outside air temperature and the like, there is a limit to the controllable temperature range. On the other hand, according to the distillation facility 1, the temperature of the cooling water itself can be freely controlled by applying the cooling water supply device 4 and adjusting the circulation amount of the refrigerant solution circulating in the refrigerator of the cooling water supply device 4. Is possible. Therefore, the pressure control of the column top 2b of the distillation column 2 is facilitated.

  By the way, conventionally, even if the low-pressure steam can be recovered, it has been difficult to reuse the recovered low-pressure steam as a heat source. The distillation facility 1 of the present embodiment has a reflux facility 3 and cools a gaseous light fraction in a reflux condenser 12 of the reflux facility 3 to obtain a liquid light fraction. Here, cooling water is used for cooling the gaseous light fraction. And this cooling water is supplied from the cooling water supply apparatus 4 using the refrigerant | coolant solution containing ammonia. Since the vapor pressure of ammonia is higher than that of water, it has been difficult to use in the past, and exhaust heat sources in the heat energy range belonging to low pressure and low temperature, for example, 0.1 MPa or more and 0.2 MPa or less, cooling water vapor of 100 ° C. or more and 160 ° C. or less. It can be used to form water. Therefore, it becomes possible to use relatively low-pressure and low-temperature steam as a heat source, and effective use of heat energy is achieved in the entire production facility including the facility for discharging low-pressure steam and the distillation facility 1.

  Moreover, since the evaporator (evaporation cooling unit) E of the cooling water supply device 4 is disposed in the vicinity of the reflux facility 3, the transport pipe L2 from the evaporator E to the reflux facility 3 can be shortened. More specifically, in the cooling water supply device 4 of the present embodiment, in the regenerator G, the condenser C, the evaporator E, and the absorber A constituting the absorption refrigerator, the regenerator G and the condenser C are supplied with the refrigerant solution. The evaporator E and the absorber A are the evaporative cooling unit 17. The refrigerant solution supply unit 16 is disposed in the vicinity of the heat supply source S that discharges the heat medium. On the other hand, the evaporator E constituting the evaporative cooling unit 17 is disposed in the vicinity of the reflux condenser 12. According to this arrangement, the distance between the evaporator E and the reflux condenser 12 is shortened, and the cooling pipe LW through which the cooling water flows can be shortened. Therefore, it is possible to suppress an increase in the temperature of the cooling water due to heat flowing in from the outside while the cooling water flows through the cooling pipe LW, and it is possible to suppress the influence of the external environment such as the atmospheric temperature on the cooling water. Further, since the ammonia concentration of the refrigerant solution M3 corresponds to the amount of heat taken from the cooling water, the cooling capacity of the cooling water supply device 4 is hardly affected by the atmospheric temperature. Therefore, it is possible to easily obtain cooling water having a stable water temperature.

  Further, a refrigerant solution M3 having a predetermined concentration is circulated through the transport pipe L2 between the condenser C and the evaporator E. That is, the thermal energy supplied from the heat supply source S is converted into a concentration difference of the solution and transported. If it does so, even if it is a case where the transportation piping L2 is long, it will become difficult to receive influence of atmospheric temperature etc., and it will become possible to transport thermal energy efficiently. Further, the heat pipes L1 to L5 that connect the regenerator G, the condenser C, the evaporator E, and the absorber A that constitute the cooling water supply device 4 do not require heat insulation and are a working medium. Since the transport amount of the refrigerant solution is small, the transport pipes L1 to L5 can be downsized and transport power can be reduced.

  Moreover, in the distillation column 2, it is desirable to set the internal pressure of the column top 2b to a relatively low pressure such as 0.05 MPa to 0.15 MPa. This is because the light fraction is easily evaporated by lowering the internal pressure in the distillation column 2 relative to the amount of heat supplied to the distillation column 2. However, the internal pressure of the column top 2b may vary depending on the raw material supplied to the distillation column 2.

  Therefore, the distillation facility 1 further includes a pressure control device 6 that controls the internal pressure of the column top 2b. The pressure control device 6 acquires the internal pressure of the column top 2b and uses the value of the internal pressure to distill the distillation column. The temperature of the liquefied light fraction returned to 2 is calculated, and the temperature of the cooling water is calculated using the temperature of the light fraction. According to this pressure control device 6, even when the internal pressure of the tower top 2b fluctuates, the circulating amount of the refrigerant solution necessary for controlling to the predetermined internal pressure is adjusted, and the cooling water temperature can be freely adjusted. Can change. Therefore, although the temperature of the cooling water is affected by the outside air temperature or the like, the internal pressure of the tower top 2b can be easily controlled as compared with the conventional case.

  In short, according to the distillation facility 1 of the present embodiment, the cooling water supply device 4 generates cooling water using exhaust heat discharged as water vapor, which has been difficult to use conventionally, and uses the cooling water to form a tower. The gaseous light fraction taken out from the top 2b is cooled. The light fraction liquefied by cooling is sent to the distillation column 2. Therefore, compared with the conventional method that cools the light gaseous fraction using water supplied from an air fin cooler (air-cooled heat exchanger) or cooling tower (cooling tower), the influence of outside temperature, etc. is suppressed. This makes it easier to control the pressure in the distillation column 2. According to this low-temperature liquid light fraction, the pressure inside the distillation column 2 is reduced. According to the low pressure inside the distillation column 2, it is possible to reduce the load of the heating device attached to the distillation column 2, and to reduce the amount of energy required for the operation of the distillation facility 1. Therefore, further energy saving can be achieved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, the heat medium supplied from the heat supply source is not limited to the above-described water vapor, and hot water (100 ° C.) may be used, for example.

  Further, lithium bromide or chlorofluorocarbon may be used as the refrigerant.

DESCRIPTION OF SYMBOLS 1 ... Distillation equipment, 2 ... Distillation tower, 2a ... Tower main part, 2b ... Tower top part, 2c ... Tower bottom part, 3 ... Reflux equipment (reflux part), 4 ... Cooling water supply apparatus (cooling water supply part), 6 ... Pressure control device (pressure control unit), 7 ... supply port, 8 ... tower top outlet, 9 ... tower body outlet, 11 ... tower bottom outlet, 12 ... reflux condenser (condenser), 16 ... refrigerant solution Supply part, 17 ... Evaporation cooling part, A ... Absorber, C ... Condenser, E ... Evaporator (evaporation cooling part), G ... Regenerator, S ... Heat supply source, P ... Pressure sensor.

Claims (3)

A distillation column that separates each fraction using the difference in boiling points of the components contained in the raw material;
A reflux unit having a condensing unit for liquefying a gaseous light fraction taken from the top of the distillation column to obtain a liquid light fraction, and returning a part of the liquefied light fraction to the distillation column And
A cooling water supply unit for supplying cooling water to the condensing unit;
With
The cooling water supply unit
The amount of heat deprived from the cooling water when the refrigerant solution evaporates is determined in correspondence with the concentration of the refrigerant in the refrigerant solution including the refrigerant having a vapor pressure higher than that of the water and disposed near the reflux unit, An evaporative cooling unit that supplies the cooling water cooled to the unit;
A distillation facility comprising: a refrigerant solution supply unit that is disposed in the vicinity of the heat supply source and supplies a refrigerant solution having a predetermined concentration to the evaporative cooling unit using a heat medium supplied from the heat supply source . A pressure control unit for controlling the internal pressure of the top of the tower;
The pressure control unit obtains the internal pressure at the top of the column, calculates the temperature of the liquefied light fraction returned to the distillation column using the value of the internal pressure, and calculates the temperature of the light fraction. The distillation facility according to claim 1, wherein the temperature of the cooling water is calculated using the cooling water, and the circulation amount of the refrigerant solution is calculated using the temperature of the cooling water.   The distillation equipment according to claim 1 or 2, wherein the heat medium is water vapor of 0.1 MPa or more and 0.2 MPa or less and 100 ° C or more and 160 ° C or less.

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