KR101373662B1 - Method and Device for saving energy in aromatic compound preparation - Google Patents

Abstract

TECHNICAL FIELD This invention relates to the manufacturing method and manufacturing apparatus of an aromatic compound. Exemplary the above production method and apparatus may include a circulation process or a circulation loop such that the process water used as the heating medium in the naphtha decomposition process is recovered after being used as the cooling medium in the production of the aromatic compound. Accordingly, according to the method and apparatus, an excellent energy saving effect can be obtained in the process of producing an aromatic compound, for example, mixed xylene or benzene.

Description

Method and device for saving energy in aromatic compound preparation

This invention relates to the manufacturing method and manufacturing apparatus of an aromatic compound.

Naphtha Cracking Center (NCC) is a facility that thermally decomposes naphtha, a gasoline fraction obtained from an atmospheric distillation unit of crude oil, to produce ethylene, propylene, butylene, BTX (Benzene / Toluene / Xylene), and the like.

Among NCC's facilities, Benzene Recovery Uni (BRU) is a facility that produces aromatic compounds such as benzene and mixed xylene using raw pyrolysis gasoline (RPG), a by-product of the process of producing ethylene or propylene using naphtha.

Processes carried out at the BRU include gasoline hydrogenation (GHT), prefractionation (PF), extraction (EXT), and hydrodealkylation (HDA). ”) Process.

The GHT process is a process of performing hydrogenation and desulfurization reaction using RPG as a raw material and separating hydrocarbons having 5 carbon atoms and hydrocarbons having 6 or more carbon atoms. The GHT process may include, for example, a primary GHT reactor in which a hydrogenation reaction is performed; A secondary GHT reactor in which hydrogenation and desulfurization reaction proceed; And a method of sequentially passing RPG as a raw material to a pentane fractionation tower in which hydrocarbons having 5 carbon atoms are separated, or a first GHT reactor in which a hydrogenation reaction proceeds; A pentane fractionation column in which hydrocarbons having 5 carbon atoms are separated; A secondary GHT reactor in which the hydrogenation reaction proceeds; And it can be carried out in such a way that the RPG sequentially pass through the stripper to the desulfurization reaction (stripper). In the GHT process, hydrocarbons having 5 carbon atoms and hydrocarbons having 6 or more carbon atoms are produced, the latter of which may be sent to the hexane dehexanizer of the PF process.

Equipment for performing the PF process may include a hexane fractionation column and a C9 hydrocarbon fractionation column. Hydrocarbons having 6 or more carbon atoms or RPG or PG (Pyrolysis Gasoline) introduced from the GHT process may be introduced into the hexane fractionation column as a raw material. Products produced in the hexane fractionation column, for example hydrocarbons having 10 or more carbon atoms, can be used for the production of mixed xylene. In addition, the product of the hexane fractionation column, for example, hydrocarbon having 7 to 9 carbon atoms can be introduced into the HDA process.

The EXT process produces benzene and the like from the products of the PF process, and the HDA process produces benzene through dealkylation from raw materials introduced from the PF process, and introduces it to the benzene fractionation tower together with the benzene produced in the EXT process. By doing so, high purity benzene can be produced.

The most important of the facilities for performing the various processes as described above is the fractionation column for separating the multi-component material contained in the raw material by the difference in boiling point. The fractionation tower may typically be configured as shown in FIG. Referring to FIG. 1, when the raw material 12 is introduced into the dividing tower 11, the vapor evaporated from the reboiler 13 inside the dividing tower 11 is upper part of the dividing tower 11. Direction, the liquid condensed in the condenser 14 is refluxed and flows toward the bottom (bottom) of the fractionation column 11. When the vapor and the liquid contact inside the fractionation column 11, the vapor is condensed and the liquid is evaporated. At this time, a component having a low boiling point tends to evaporate, and a component having a high boiling point tends to condense. The concentration of the low boiling point component increases toward the top of the column 11. As a result, pure low-boiling steam is obtained at the upper part of the fractionation tower 11, which is condensed by the condenser 14, partly produced as a product, and partly refluxed. The refluxed reflux liquid is used to condense the high boiling point components coming to the top and send it to the bottom of the column. In addition, some of the high boiling point components discharged from the lower portion of the fractionation tower 11 are also produced as products, and others are evaporated again in the reboiler 13 and then sent to the lower portion of the fractionation tower 11 to be used to evaporate internal components. Can be.

In the fractionation tower, the raw material inflow, the evaporation by the reboiler 13 and the condensation and reflux process by the condenser 14 are repeated, and a high purity product is produced. In 13) huge amounts of energy are used, for example steam. Therefore, a huge amount of energy is required in a BRU including a plurality of distillation columns.

An object of this invention is to provide the manufacturing method and manufacturing apparatus of an aromatic compound.

The manufacturing method of the aromatic compound of this invention is related. In the exemplary method, processing water (PW) is contacted with the bottom product of the fractionation column of the NCC, and for the production of the top product of the fractionation column or the production of BRU or mixed xylene during the production of BRU or mixed xylene. And circulating in contact with the raw material introduced. Such circulation may be carried out using a piping system forming a circulation loop. The circulated process water can act as a heating or cooling medium in each of the contacting steps.

In the exemplary method, the process water is heat-exchanged with the bottom product of the fractionation column in the process of NCC, and back to the top product of the fractionation column of the BRU process or the fractionation column of the production process of the mixed xylene or the BRU process or the mixed xylene process. It may be recovered after heat exchange with the raw material introduced. In the process of heat exchange with the bottom product of the fractionation tower, the process water acts as a heating medium, and in the process of heat exchange with the top product or the raw material of the fractionation tower of the BRU or mixed xylene production process, the process water may act as a cooling medium. have.

The method may be, for example, a method of operating an NCC, a BRU or a mixed xylene production process or an energy saving method.

In one example, as the process water, industrial water from which impurities such as minerals are removed may be used. The process water may be used as the heating medium and the cooling medium in the above method.

An exemplary method may include supplying the process water to a naphtha cracking process, for example, a process of NCC, and exchanging heat with the bottom product of the fractionation column where the naphtha cracking process is performed.

In addition, the method, a process for producing an aromatic compound in the process water after the heat exchange with the bottom product of the fractionation column in which the naphtha decomposition process proceeds, for example, for the process of BRU or for the production of mixed xylene Supplying a process, it may include the step of heat exchange with the top product of the fractionation column of the process for producing the aromatic compound.

The process water after the heat exchange with the bottom product of the fractionation column in which the naphtha decomposition process is performed is supplied to a process for producing aromatic compounds, for example, a process for BRU or a process for producing mixed xylene. It may be heat exchanged with raw materials such as RPG, PG or hydrocarbons having 6 or more carbon atoms.

In one example, the temperature of the process water supplied for heat exchange with the bottom product of the fractionation column in which the naphtha decomposition process is performed, that is, the temperature of the process water before heat exchange with the bottom product is, for example, 95 ° C to 125 ° C, 100 ° C to 120 ° C or about 110 ° C. By maintaining the temperature of the process water to be supplied as described above, it is possible to properly heat exchange with the upper or lower products of the fractionation column in the place where the process water circulating the circulation loop is necessary, and to allow the efficient process to proceed.

In one example, the process water may be supplied from a process water storage tank. The storage tank may be operated such that the process water supplied in the normal operation is maintained in the temperature, that is, in the range of 95 ° C to 125 ° C, 100 ° C to 120 ° C, or about 110 ° C. In one example, the process water has a storage temperature of about 95 ° C to 125 ° C, 100 ° C to 120 ° C, or about 110 ° C, and a storage pressure of about 0.5 Kg / cm ² G to 0.8 Kg / cm ² G, 0.6 Kg. / cm ² G to 0.7 Kg / cm ² G or about 0.65 Kg / cm ² G on the order can be supplied from the process water storage tank. The type of the storage tank is not particularly limited as long as it can maintain the storage temperature and the storage pressure as described above. For example, a storage tank having a low pressure steam jet device or the like may be used.

For example, the process water may be supplied from the storage tank to a fractionation tower in which a naphtha decomposition process is performed.

2 is a diagram schematically showing a process of supplying the process water. As shown in FIG. 2, the process water may be supplied from the storage tank 21 to the fractionation towers 22 and 23 where the naphtha decomposition process is performed by a circulation pump installed at an appropriate position.

The fractionation column in which the naphtha decomposition process is performed may be, for example, at least one selected from the group consisting of an ethane fractionation column and a propane fractionation column.

For example, as shown in FIG. 2, the process water may be supplied to the NCC and first supplied to the ethane fractionation tower 22 to exchange heat with the lower product of the fractionation tower 22. As a result, the process water heats the bottom product of the fractionation tower 22 and can cool itself. In one example, the temperature of the process water after heat exchange with the bottom product of the fractionation column 22 may be about 85 ° C. to 115 ° C., 90 ° C. to 110 ° C., or about 100 ° C. to about 102 ° C. In addition, the bottom product of the fractionation column 22 may have a temperature of about 80 ° C to 100 ° C before heat exchange with the process water, and a temperature of about 85 ° C to 105 ° C after heat exchange.

The process water heat-exchanged with the bottom product of the ethane fractionation tower 22 may be supplied to the propane fractionation tower 23 again to further exchange heat with the bottom product of the fractionation tower 23. Thereby the process water also heats the bottom product of the fractionation tower 23, which itself can be cooled. In one example, the temperature of the process water after the heat exchange with the lower product of the fractionation column 23 may be about 80 ° C to 110 ° C, 85 ° C to 105 ° C, or about 95 ° C to 97 ° C. In addition, the bottom product of the fractionation column 23 has a temperature of about 80 ° C to 85 ° C before heat exchange with the process water, and after the heat exchange, the fractionation column 23 of the fractionation column 23 at a temperature of about 85 ° C to 88 ° C. It can be refluxed downward.

As described above, the process water heat exchanged with the product of the fractionation tower of the naphtha decomposition process may be supplied to a process for producing BRU or mixed xylene.

In one example, the process water may undergo a temperature correction process before being fed into a process for producing BRU or mixed xylene.

That is, the method, heat exchange with the raw material introduced into the upper product of the dividing column for producing an aromatic compound or the process product heat-exchanged with the lower product of the distillation column in which the naphtha decomposition process proceeds The step of adjusting the temperature of the process water may be further performed before the step. The temperature of the process water in the above may be adjusted to about 90 ℃ to 100 ℃, about 92 ℃ to 98 ℃ or about 95 ℃ degree. As such, by controlling the temperature of the process water, subsequent processes may be smoothly and efficiently performed. The temperature of the process water can be adjusted, for example, by installing a cooling device or a heating device at an appropriate position of the circulation loop. Typically, the fractionation tower of the naphtha cracking process and the process water after heat exchange have a higher temperature than the temperature to be controlled, and thus a cooling device may be installed in the circulation loop.

The process water heat exchanged with the product of the fractionation column of the naphtha cracking process may be fed to the process for producing BRU or mixed xylene after the temperature control process, if necessary. The process water supplied can be heat exchanged with the raw materials of the BRU or mixed xylene production or with the top products of the fractionation tower used in the process.

In one example, the raw material heat-exchanged with the process water may be, for example, a high temperature raw material introduced into the GHT process, and examples of such raw material may include PG or RPG. Heat exchange with the raw material as described above, for example, may be performed by adjusting the circulation loop so that the flow of the process water flows into the fuselage side of the heat exchanger of the reactor in which the GHT process is performed. As mentioned above, the process water heat-exchanged with a raw material is about 90 degreeC-100 degreeC, about 92 degreeC-98 degreeC, or about 95 degreeC, for example, and the temperature after heat exchange is about 95 degreeC-125 degreeC, It may be about 100 ℃ to 120 ℃ or about 110 ℃. In addition, the process water heat-exchanged as described above may be recovered along the circulation loop and reduced back to the process water storage tank.

In addition, the raw material heat-exchanged with the process water is, for example, the temperature before the heat exchange is about 130 ℃ to 160 ℃ or about 140 ℃ to 150 ℃ degree, the temperature after heat exchange is about 100 ℃ to 130 ℃ or about 110 ℃ It may be about 120 ℃. In addition, the raw material undergoing such heat exchange may be introduced into the production process of the aromatic compound or the production of mixed xylene.

In addition, the upper product of the fractionation column of the process for producing BRU or mixed xylene heat-exchanged with the process water is, for example, at least one fractionation column selected from the group consisting of hexane fractionation tower, mixed xylene tower and benzene tower. It may be a top product of. Such heat exchange may be performed, for example, by adjusting a circulation loop to allow the flow of process water into the condenser at the top of the fractionation tower. For example, the process water heat-exchanged with the upper product is about 90 ° C to 100 ° C, about 92 ° C to 98 ° C or about 95 ° C before heat exchange, and the temperature after heat exchange is about 95 ° C to 125 ° C. , 100 ° C. to 120 ° C., or about 110 ° C. In addition, the process water heat-exchanged as described above may be recovered along the circulation loop and reduced back to the process water storage tank.

로 표시된 부분은, 도 2의

로 표시된 배관과 연결되어 있음을 의미할 수 있고, 또한

로 표시된 부분은, 도 2에서

로 표시된 배관과 연결되어 있음을 의미할 수 있다.3 is a diagram schematically showing one example of the heat exchange process as described above. 3,

The part indicated by,

May be connected to the pipe marked as

In the part indicated by,

It may mean that it is connected to the pipe marked with.

Referring to FIG. 3, process water introduced through heat exchange in the naphtha cracking process may be introduced into a process for producing aromatic compounds via a cooling device 31, which is a temperature control device installed at an appropriate position of a circulation loop, as necessary. Can be.

As shown in FIG. 3, a part of the flow of the process water passing through the cooling device 31 is a heat storage tank, for example, the process water storage tank of FIG. 2 after being heat-exchanged with RPG and PG as raw materials. 21). In FIG. 3, for example, the process water is heat-exchanged with the RPG while passing through the heat exchanger H1, and is also heat-exchanged with PG while passing through the heat exchanger H2. In addition, through the heat exchange, the raw material RPG or PG is cooled to an appropriate level, and accordingly, it may be possible to reduce the cooling load of the cooler in a subsequent process, and to reduce power consumption and power. Thus, the raw material cooled by heat exchange can be supplied to the fractionation tower, for example, the hexane fractionation tower 32.

In FIG. 3, a portion of the flow of process water passing through the cooling device 31 may also be fed to the hexane fractionation tower 32 to exchange heat with the top product of the fractionation tower 32. Accordingly, the process water at which the temperature before the heat exchange was about 90 ° C. to 100 ° C., about 92 ° C. to 98 ° C. or about 95 ° C. is about 95 ° C. to 125 ° C., 100 ° C. to 120 ° C. or about 110 ° C. after heat exchange. The heated process water may be recovered along the circulation loop and reduced back to the process water storage tank (21 in FIG. 2).

In one example, the operating temperature of the top of the column of the hexane fractionation tower 32 for discharging the top product heat exchanged with the process water may be about 100 ℃ to 130 ℃, about 110 ℃ to 120 ℃ or about 113 ℃ to 115 ℃ degree have. In addition, the operating pressure of the upper part of the tower may be, for example, about 1.0 Kg / cm ² G to 3.0 Kg / cm ² G or about 1.5 Kg / cm ² G to 2.5 Kg / cm ² G. The operation temperature and pressure as described above are relatively high compared to the operation temperature and pressure of the hexane fractionation tower in the existing NCC or BRU. Due to the high operating temperature and pressure, the hexane fractionation tower 32 discharges the upper product having a higher temperature than the conventional one, and accordingly, the process water recovered through the heat exchange to the storage tank maintains an appropriate temperature, thereby improving the efficiency of forming the circulation loop. Can increase. In addition, due to the setting of the operating temperature and pressure as described above, a cooler, for example, an air fin type cooler used in the conventional hexane fractionation column may not be used, and thus an additional energy saving effect may be obtained.

Under the above conditions, a part of the upper product of the fractionation column 32 subjected to the heat exchange process with the process water may be refluxed to the fractionation column 32, and some may be supplied as a raw material of the benzene tower 35. In addition, the bottom product of the fractionation tower 32 may be supplied as a raw material of the by-product fuel oil fractionation tower 33.

In the by-product fuel oil fractionation tower 33, a fractionation process may be performed using the lower product of the fractionation column 32 as a raw material. The top product of the fractionation tower 33 may, for example, be partially refluxed back to the top of the fractionation tower 33, and the other part may be supplied to the plant 38 where the HDA process proceeds. The flow through the plant 38 of the HDA process can be supplied, for example, as a raw material of the benzene tower 35. In addition, the bottom product of the fractionation tower 33 may be supplied as a raw material of the mixed xylene tower 34.

A portion of the flow of process water that has passed through the cooling device 31 may also be supplied to the mixed xylene tower 34 to exchange heat with the top product of the mixed xylene tower 34.

In one example, the operating temperature of the top of the tower of the mixed xylene tower 34 may be about 130 ° C to 170 ° C or about 140 ° C to 160 ° C. In addition, the operating pressure of the upper portion of the tower may be, for example, about 0.2 Kg / cm ² G to 0.7 Kg / cm ² G or about 0.3 Kg / cm ² G to 0.55 Kg / cm ² G. In addition, the operating temperature of the tower bottom of the tower 34 may be about 170 ℃ to 210 ℃ or about 180 ℃ to 200 ℃ degree. In addition, the operating pressure of the bottom of the tower may be, for example, about 0.3 Kg / cm ² G to 0.8 Kg / cm ² G or about 0.4 Kg / cm ² G to 0.65 Kg / cm ² G. At this operating temperature and pressure, the process can proceed smoothly.

In the tower 34, for example, the fractionation process of the raw material supplied from the by-product fuel oil fractionation tower 33 may be performed. The top product of the tower 34 is, for example, after being heat exchanged with the process water as described above, partly refluxed to the top of the tower 34 and the other part is stored in the storage tank 37 as a product. Can be. In addition, the bottom product of the tower 34 may be supplied to the equipment 38 in which the HDA process proceeds, and the flow through the HDA process may be supplied as a raw material of the benzene tower 35, for example. .

The process water heat-exchanged with the upper product of the mixed xylene tower 34 may have a temperature of about 90 ° C. to 100 ° C., about 92 ° C. to 98 ° C., or about 95 ° C. before heat exchange. The heated process water may be recovered along the circulation loop and reduced back to the process water storage tank (21 in FIG. 2).

A portion of the flow of process water that has passed through the cooling device 31 can also be fed to the benzene tower 35 to exchange heat with the top product of the fractionation tower 35.

In the benzene tower 35, for example, the fractionation process of the raw material introduced through the hexane fractionation column 32 or the HDA process may be performed.

In one example, the operating temperature of the tower top of the benzene tower 35 may be about 100 ° C to 140 ° C or about 110 ° C to 130 ° C. In addition, the operating pressure of the upper portion of the tower may be, for example, about 0.5 Kg / cm ² G to 3.5 Kg / cm ² G or about 1 Kg / cm ² G to 3 Kg / cm ² G. In addition, the operating temperature of the bottom of the tower 35 may be about 145 ° C to 185 ° C or about 155 ° C to 175 ° C. In addition, the operating pressure of the lower portion of the benzene tower 35 may be, for example, about 1 Kg / cm ² G to 4 Kg / cm ² G or about 1.5 Kg / cm ² G to 3.5 Kg / cm ² G. At this operating temperature and pressure, the process can proceed smoothly.

The top product of the benzene tower 35 may be refluxed back to the top of the benzene tower 35, for example, after heat exchange with the process water as described above. In addition, the bottom product of the benzene tower 35 may be fed to the recycle tower (36). In the recirculation tower 36, the classification process of the raw materials to be supplied may be performed. The top product which has undergone the sorting process in the recirculation tower 36 is stored in the storage tank 39 and then partly refluxed to the recirculation tower 36, and part of it may be produced as a product. In addition, the bottom product of recycle column 36 may be fed to plant 40, for example, where a heavy aromatic extraction process proceeds.

The process water heat-exchanged with the upper product of the benzene tower 35 may have a temperature of about 90 ° C. to 100 ° C., about 92 ° C. to 98 ° C., or about 95 ° C. before heat exchange. The heated process water may be recovered along the circulation loop and reduced back to the process water storage tank (21 in FIG. 2).

In one example, the process water heat-exchanged with the raw material PG or RPG, or the upper product of each fractionation column, is maintained at a temperature of about 95 ℃ to 125 ℃, 100 ℃ to 120 ℃ or about 110 ℃ by the heat exchange , May be reduced back to the storage tank (21 in FIG. 2) along the circulation loop. The reduced process water may be supplied to the naphtha cracking process again and, for example, the heat exchange process with the bottom products of the ethane fractionation tower or the propane fractionation column may be repeated.

That is, the method, the upper product of the fractionation column for producing an aromatic compound or the lower part of the fractionation column in which the naphtha decomposition process is carried out to the process water which has undergone heat exchange with the raw material introduced into the fractionation column for producing the aromatic compound. Recovering may be further included to heat exchange with the product.

By allowing the process water circulating through the circulation loop to act as a heating medium and a cooling medium, for example, the use of low pressure steam used in lower reboilers of ethane or propane fractionation towers in existing NCC or BRU processes is reduced or omitted. It is also possible to reduce or reduce the use of cooling water or air coolers used for cooling the raw materials or overhead products of the fractionation tower.

The present invention also relates to an apparatus for producing aromatic compounds. Exemplary the device may be configured to be used in the above-described method for producing an aromatic compound. Therefore, with respect to the specific matters of the apparatus, the matters already described may be equally applied.

That is, the exemplary apparatus includes a process water storage tank, a fractionation column capable of performing a naphtha decomposition process, and a fractionation column for producing an aromatic compound; And plumbing systems. The piping system may form a circulation loop connecting the process water storage tank, the fractionation column capable of performing the naphtha decomposition process, and the fractionation column for producing the aromatic compound.

The piping system may form a loop in which process water flowing out of the process water storage tank may be contacted for heat exchange with the bottom product of the fractionation tower capable of carrying out the naphtha cracking process. In addition, after the process water is contacted for heat exchange with the lower product of the fractionation column capable of performing the naphtha decomposition process, the upper product of the fractionation column for producing the aromatic compound or the raw material introduced into the fractionation column for heat exchange. It may be forming a loop that can be.

The piping system may also form a circulation loop such that process water contacted for heat exchange with the top product of the fractionation tower for producing aromatics or the raw material introduced into the fractionation tower can be recovered to the process water storage tank. .

In addition, as described above, the piping system may include a top product of the fractionation column for producing the aromatic compound after the process water is contacted for heat exchange with a bottom product of the fractionation column capable of performing the naphtha cracking process or A loop may be formed to pass through a temperature controller, for example, the cooling device or the heating device, before contacting the raw material introduced into the fractionation column for heat exchange.

Exemplary the above production method and apparatus may include a circulation process or a circulation loop such that the process water used as the heating medium in the naphtha decomposition process is recovered after being used as the cooling medium in the production of the aromatic compound. Accordingly, according to the method and apparatus, an excellent energy saving effect can be obtained in the process of producing an aromatic compound, for example, mixed xylene or benzene.

1 is an exemplary diagram for explaining the function of a classification tower.
2 and 3 are diagrams for exemplarily explaining the manufacturing method.

Hereinafter, the method and apparatus will be described in more detail with reference to Examples, but the scope of the method and apparatus is not limited by the Examples set forth below.

Example 1

For the NCC and BRU processes, a process water circulation loop as shown in FIGS. 2 and 3 was formed, and the production process of the aromatic compounds benzene and mixed xylenes was simulated.

In the process water storage tank 21, a tank having a low pressure steam jet device is operated at a storage temperature of about 110 ° C. and a storage pressure of about 0.65 Kg / cm ² G, and operating at a temperature of about 110 ° C. in a steady state. Water was supplied to the bottom of the ethane separation tower 22.

The process water was supplied to the lower heat exchanger of the ethane fractionation tower 22 by a pump installed in a circulation loop to exchange heat with the lower product of the fractionation tower 22. The process water was withdrawn at a temperature of about 101.8 ° C. after heat exchange with the bottom product of the fractionation tower 22. In addition, the bottom product of the fractionation tower 22 was introduced into the heat exchanger at a temperature of about 90.2 ° C, heated to a temperature of about 95.5 ° C after heat exchange with the process water, and flowed into the fractionation tower. In this process, the process water was calculated to supply about 9.334 MM Kcal / hr of heat to the bottom product of the fractionation column 22.

The process water heat exchanged with the bottom product of the ethane fractionation tower 22 was again heat exchanged with the bottom product of the propane fractionation tower 23. As a result, the process water at a temperature of about 101.8 ° C. was cooled to a temperature of about 96.4 ° C. after the heat exchange.

In addition, the bottom product of the propane fractionation tower 23 was introduced into the heat exchanger at a temperature of about 82.7 ° C, heated to about 86.9 ° C after heat exchange with the process water, and flowed into the fractionation tower 23. In this process, the process water was calculated to supply about 6.11 MM Kcal / hr of heat to the bottom product of the propane fractionation column 23.

The process water which heat-exchanged with the lower products of the ethane and propane fractionation towers 22 and 23 of NCC was made into the cooling apparatus 31, and was heat-exchanged with cooling water, and the temperature was adjusted to about 95 degreeC.

A part of the flow of the temperature-corrected process water in the cooling device 31 was supplied to the fuselage side of the heat exchanger indicated by H1 in FIG. 3 to heat exchange with the RPG supplied from the GHT. By the heat exchange, the temperature of the RPG was cooled from 146.7 ° C. to about 117 ° C., thus reducing the cooling load of the first stage reactor cooler. In addition, in the process water undergoing heat exchange, the temperature was raised from about 95 ° C. to about 110 ° C. to generate heat absorption. The process water that had undergone heat exchange was recovered to the process water storage tank 21 again along the circulation pipe.

In addition, a part of the flow of the process water whose temperature was calibrated to about 95 ° C. in the cooling device 31 was passed through the observation of the process heat exchanger H2 of the line of PG supplied from the GHT to exchange heat with the PG. By the heat exchange, the temperature of PG was cooled from 144.8 ° C to about 115 ° C. In addition, the temperature of the process water subjected to heat exchange was increased from about 95 ° C to about 110 ° C, and heat absorption occurred. The process water that had undergone heat exchange was recovered to the process water storage tank 21 again along the circulation pipe.

In addition, the upper part of the hexane separation tower 32, the mixed xylene tower 34, and the benzene tower 35, while a part of the flow of the process water whose temperature has been corrected to about 95 DEG C in the cooling device 31 is moved along the pipe. Heat exchanged sequentially with

The process water is recovered in the process water storage tank 21 in a state in which the temperature is raised to about 110 ° C. by absorbing 3.6145 MM Kcal / hr of heat from the upper product during heat exchange with the upper product of the hexane fractionation tower 32. It became. In addition, the operating temperature of the tower top of the hexane fractionation column 32 was about 114.2 degreeC, and the operation pressure was about 1.8 Kg / cm <^2> G.

In addition, the process water heat-exchanged with the upper product of the mixed xylene tower 34 was also recovered to the storage tank 21 along the pipe while the temperature rose from about 95 ° C to about 110 ° C, which was about 4.1479 MM during the heat exchange process. It was confirmed that Kcal / hr of heat was absorbed. In addition, in the mixed xylene tower 34, the operating temperature of the top of the tower was about 151.2 ° C, the operating pressure was about 0.47 Kg / cm ² G, and the operating temperature of the bottom of the tower was about 193 ° C, The operating pressure was about 0.533 Kg / cm ² G.

In addition, the process water heat-exchanged with the upper product of the benzene tower 35 was recovered to the storage tank 21 along the pipe while the temperature rose from about 95 ° C to about 110 ° C, which was about 5.7389 MM Kcal during the heat exchange process. It confirmed that the heat of / hr was absorbed. In addition, the benzene tower 35 had an operating temperature of about 118.1 ° C. at the top of the tower, an operating pressure of about 1.95 Kg / cm ² G, an operating temperature of about 166.5 ° C. at the bottom of the tower, and an operating pressure of , About 2.44 Kg / cm ² G.

When the process water flows out of the storage tank 21 and passes through the one circulation loop, the amount of heat consumed or obtained by heat exchange at each location is summarized in Table 1 below.

Calories obtained
(Unit: MM Kcal / hr) Calories consumed
(Unit: MM Kcal / hr) Ethane Sorting Tower (22) - 9.3340 Propane sorting tower (23) - 6.1100 One Stage Reactor Effluent Heat Exchanger (RPG) 1.7339 - Reactor Effluent Heat Exchanger (PG) 1.8436 - Hexane fractionation tower (32) condenser 3.6145 - Mixed Xylene Towers (34) Condenser 4.1479 - Benzene Tower (35) Condenser 5.7389 - sum 17.0788 15.4440

11: classification tower
12: flow of raw material
13: Swallow
14: Condenser
21: process water storage tank
22: ethane sorting tower
23: propane fractionation tower
31: cooling system
32: hexane fractionation tower
33: by-product fuel oil fractionation tower
34: mixed xylene tower
35: benzene tower
36: Recirculation Tower
37: storage tank
38: HDA process equipment
39: storage tank
40: heavy aromatic compound production equipment

Claims (9)

Supplying process water to a naphtha cracking process to perform heat exchange between the bottom product of the fractionation column in which the naphtha cracking process is performed and the process water; And a process water having a temperature of 80 ° C. to 110 ° C. as a process water after performing heat exchange with a lower product of a fractionation column in which the naphtha decomposition process is performed, to produce an upper product of the fractionation column or the aromatic compound for producing an aromatic compound. Energy saving method of the manufacturing process of the aromatic compound comprising the step of heat-exchanging with the raw material introduced into the fractionation column for. The energy saving method of claim 1, wherein the process water supplied for heat exchange with the lower product of the fractionation column in which the naphtha decomposition process is performed has a temperature of 95 ° C to 125 ° C. The method of claim 1, wherein the fractionation column undergoing the naphtha decomposition process is at least one selected from the group consisting of an ethane fractionation column and a propane fractionation column. delete The raw material introduced to the fractionation column for producing the aromatic compound or the upper product of the fractionation tower for producing an aromatic compound, or the process water subjected to heat exchange with the lower product of the fractionation column in which the naphtha decomposition process is performed. Energy-saving method of the process for producing an aromatic compound further comprising the step of adjusting the temperature of the process water to 90 ℃ to 100 ℃ before heat exchange with. The method of claim 1, wherein the raw material introduced to the fractionation column for producing the aromatic compound is PG (Pyrolysis Gasoline) or RPG (Raw Pyrolysis Gasoline). The method of claim 1, wherein the fractionation column for producing the aromatic compound is at least one selected from the group consisting of a hexane fractionation column, a mixed xylene column, and a benzene column. According to claim 1, wherein the upper product of the fractionation tower for producing an aromatic compound or the process water that is subjected to heat exchange with the raw material introduced into the fractionation tower for producing the aromatic compound, the lower product of the fractionation column is subjected to the naphtha decomposition process. Energy saving method of the manufacturing process of the aromatic compound further comprising the step of recovering for heat exchange with. Process water storage tank, fractionation tower capable of performing naphtha decomposition process, fractionation tower for producing aromatic compounds; And a piping system, wherein the piping system forms a circulation loop connecting the process water storage tank, a fractionation column capable of performing the naphtha decomposition process, and a fractionation column for producing the aromatic compound, The circulation loop is the top product of the fractionation tower or the fractionation for producing the aromatic compound after the process water flowing out of the process water storage tank is contacted for heat exchange with the bottom product of the fractionation column capable of performing the naphtha cracking process. Energy-saving device of the manufacturing process of the aromatic compound formed to be in contact with the raw material introduced into the tower for heat exchange.

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