JP6026714B1 - Condensate processing system - Google Patents

Abstract

An object of the present invention is to provide a system that can reduce operating energy when processing condensate to produce products such as LPG, light naphtha, heavy naphtha, kerosene and light oil. The condensate is collectively hydrodesulfurized in a hydrotreating unit 1 and then supplied to a preflash distillation column 2 to supply a gas component containing LPG and a light naphtha fraction and a heavy naphtha fraction. A heavy fraction which is a liquid component is separated. The heavy fraction is fed to the main distillation column 4 at the subsequent stage and fractionated into a heavy naphtha fraction, a kerosene fraction and a light oil fraction, or further fractionated into a heavy residue. The gas component is fractionated into LPG and light naphtha in the debutane tower 5. [Selection] Figure 1

Description

  The present invention relates to a system for processing condensate to produce products such as LPG (Liquefied Petroleum Gas), light naphtha, heavy naphtha, kerosene and light oil.

When producing natural gas, a part of the gas phase is liquefied by depressurization and cooling, and light liquid hydrocarbons are obtained. This hydrocarbon is called natural gas condensate or condensate oil, and has the characteristics that it has more light fractions and less heavy fractions than crude oil. It is a natural resource that is expected as a source of chemical raw materials and energy. is there. In the present application, this hydrocarbon is simply referred to as “condensate”.
As a method of hydrorefining condensate (desulfurization), if the condensate is fractionated into each fraction and desulfurization is performed for each fraction, a desulfurization unit for each product is required. Soaring.

In Patent Document 1, in order to solve such a problem, hydrodesulfurization treatment is collectively performed on the condensate, the desulfurized condensate is distilled and separated by an atmospheric distillation apparatus, and LPG and naphtha distillate are separated. Extraction of a naphtha fraction, a kerosene fraction and a light oil fraction, and separation of a naphtha fraction into light naphtha and heavy naphtha in a naphtha fractionation tower. Patent Document 2 also describes a technique in which hydrodesulfurization treatment is collectively performed on condensate and fractional distillation is similarly performed in an atmospheric distillation column.
In this way, condensate is a useful resource, and the technology for extracting each product is known, but it reduces the construction cost of the condensate treatment facility, that is, the hydrocarbon oil production system, and the operating energy. It is requested.

JP 2007-238832 A JP 2010-1111778 A

  The present invention has been made under such circumstances, and is a system capable of reducing operating energy when manufacturing products such as LPG, light naphtha, heavy naphtha, kerosene and light oil by processing condensate. Is to provide.

The present invention is a system for processing condensate,
A desulfurization unit for hydrodesulfurizing condensate;
Condensate hydrodesulfurized by the desulfurizer is supplied, and includes gas components including liquefied petroleum gas and light naphtha fraction, and heavy naphtha fraction and heavy fraction having a higher boiling point than heavy naphtha fraction. A liquid component, a preflash distillation column for fractional distillation,
A reboiler for heating the liquid component at the bottom of the preflash distillation column;
A heating unit for heating the liquid component taken out from the bottom of the preflash distillation column to a temperature higher than the temperature of the reboiler;
A main distillation column for fractionating the liquid component heated in the heating unit into at least a heavy naphtha fraction, a kerosene fraction, and a light oil fraction.

  In the present invention, condensate is collectively hydrodesulfurized, and then supplied to a preflash distillation column to extract LPG and light naphtha fractions. For heavy fractions containing heavy naphtha fractions, It is fed to a tower and fractionated into a heavy naphtha fraction, a kerosene fraction and a light oil fraction, or further fractionated into a heavy residue. Since the condensate contains a large amount of light components and the light components are separated by the preflash distillation column, the operating pressure in the main distillation column can be lowered. Therefore, in addition to the fact that the raw material supplied to the main distillation column is small, the amount of fuel consumed in the heating section provided in the front stage of the main distillation column can be kept low, and the system can be operated with less energy. In addition, the fact that the system can be operated with less energy can reduce the size of the heating part and the cooling part, so that the construction cost can be expected to be kept low.

It is a block diagram which shows the whole structure of the processing system of the condensate which concerns on embodiment of this invention. It is a block diagram which shows the whole structure of the processing system of the condensate used for calculation of an operating energy corresponding to this invention. It is a block diagram which shows the whole structure of the processing system of the condensate corresponding to the comparative example used for calculation of operating energy.

The condensate treatment system of the present invention is provided with a reaction tower 1 which is a hydrotreating section (desulfurization apparatus) for performing desulfurization all at once before fractionating the condensate. In the reaction tower 1, for example, a plurality of catalyst layers formed by supporting a hydrogenation catalyst on a carrier are provided. As the hydrogenation catalyst, a Co—Mo system, a Ni—Mo system, a Ni—Co—Mo system, or the like can be used, but the hydrogenation catalyst is not limited thereto. A supply line 1a that is a pipe that forms a flow path is connected to the upper portion of the reaction tower 1, and a heating furnace 10 that is a heating unit is provided in the supply pipe 1a. The condensate is mixed with hydrogen gas, for example, at the front stage of the heating furnace 10, heated to, for example, 250 ° C. to 370 ° C. in the heating furnace 10, and supplied into the reaction tower 1 from the upper part of the reaction tower 1.
When the condensate passes through the catalyst layer together with hydrogen gas, sulfur contained in the condensate is converted into hydrogen sulfide by a hydrogenation reaction. The pressure in the reaction tower 1 is set to, for example, 4.0 MPaG to 7.0 MPaG.

  Connected to the bottom of the reaction tower 1 is a feed line 1b consisting of piping that forms a flow path for extracting the condensate in the reaction tower 1 and sending it to the pre-flash distillation tower 2 at the subsequent stage, and downstream of this feed line 1b. The side is connected to the central part of the preflash distillation column 2, for example between the top and the bottom of the column. An extraction line 2 a for extracting a liquid component is connected to the bottom of the preflash distillation column 2. In the middle of this extraction line 2a, a pump 21 and a heating furnace 3 as a heating unit are connected, and the downstream end of the extraction line 2a is connected to the main distillation column 4.

  A branch line 2b is branched from the downstream side of the pump 21 in the extraction line 2a, a reboiler 22 is provided in the middle of the branch line 2b, and the downstream side of the branch line 2b is connected to the bottom of the preflash distillation column 2. It is connected. That is, a part of the extraction line 2a and the branch line 2b form a circulation line for returning the liquid component accumulated at the bottom of the preflash distillation column 2 to the bottom. The heating temperature in the reboiler 22 is set to 200 ° C. to 300 ° C., for example.

  The condensate supplied to the preflash distillation column 2 is heated by the reboiler 22 under pressure from the light fraction, which is a gas component including LPG and light naphtha fraction, from the heavy naphtha fraction and heavy naphtha fraction. And a liquid component containing a heavy fraction having a high boiling point. Since the condensate contains 30% or more of light naphtha, for example, the heavy fraction extracted from the bottom of the column is less than 70% of the condensate supplied to the preflash distillation column 2, for example.

The heavy fraction extracted from the bottom of the preflash distillation column 2 is heated to a temperature higher than the heating temperature of the reboiler 22, for example, 250 ° C. to 350 ° C. in the heating furnace 3 as a heating unit.
The main distillation column 4 is an atmospheric distillation column composed of, for example, a plate column, and the extraction line 2a is connected to a position below the lowermost tray, for example.
In the case of general crude oil refining, stripping with steam is performed at the bottom of the tower to remove the light fractions in the heavy residue, so that the outlet temperature of the previous heating furnace does not rise too much. The connection position of the supply line is a position where the raw material is supplied to, for example, the fourth to tenth trays of the distillation column. On the other hand, in this embodiment, since the raw material is condensate, it is light, and since the operating pressure of the main distillation column 4 is low, the outlet temperature of the heating furnace 3 is specified without stripping by steam. It does not increase to a value (for example, 375 ° C.), and the flash point specification of heavy residue is satisfied. Therefore, when viewed from the downstream side of the extraction line 2a, that is, from the main distillation column 4, the supply position of the raw material supply line is set to a position below the lowermost tray.

  In the main distillation column 4, the pressure is operated, for example, at 0 MPaG to 0.2 MPaG. A liquid component containing a heavy naphtha fraction extracted from the bottom of the preflash distillation column 2 and a heavy fraction having a boiling point higher than that of the heavy naphtha fraction is fractionated in the main distillation column 4, A heavy naphtha fraction is extracted from the top extraction line 4a, and a kerosene fraction and a light oil fraction are extracted from the extraction lines 4b and 4c on the side wall of the tower, respectively. A heavy oil fraction, which is a heavy residue, is extracted from the extraction line 4d at the bottom of the tower. Condensate has a heavy residue content of, for example, 10% by mass or less, and is considerably low. Depending on the condensate used as a raw material, the extraction line 4d is not used, that is, the heavy residue is not fractionally separated. There is also.

  On the other hand, from the extraction line 2c at the top of the preflash distillation column 2, a light fraction that is a gas component including LPG and a light naphtha fraction is extracted. The extraction line 2 c is provided with a heat exchanger 51, and the downstream end of the extraction line 2 c is connected to the debutane tower 5. An extraction line 5a for extracting a light naphtha fraction, which is a liquid component, is connected to the bottom of the debutane tower 5, and a branch line 5b branches from the middle of the extraction line 5a. The branch line 5b is provided with a reboiler B3 that is heated by steam, and the bottom of the tower is heated to 120 ° C. to 220 ° C., for example.

  In the debutane tower 5, the reboiler B3 is heated to be fractionated into LPG as a gas component and a light naphtha fraction as a liquid component. Therefore, LPG is extracted from the extraction line 5c at the top of the column, and a light naphtha fraction is extracted from the extraction line 5a at the bottom of the column. A part of the liquid component at the bottom of the column circulates from the extraction line 5a through the branch line 5b, and a part of the extraction line 5a and the branch line 5b form a circulation line. The light naphtha fraction extracted to the extraction line 5a is cooled by heat exchange with the liquid component extracted from the top of the preflash distillation column 2 by the heat exchanger 51.

  In the above-described embodiment, the condensate is collectively desulfurized in the hydrotreating section (reaction tower 1), and then separated into a light fraction and a heavy fraction in the preflash distillation tower 2, and the heavy fraction is separated. The portion is fed to the main distillation column 4. Since the condensate contains a lot of light fractions, and the light fractions are removed in the preflash distillation column 2 before being supplied to the main distillation column 4, the operation pressure in the main distillation column 4 can be reduced. Generation of off-gas is suppressed. Thus, since the raw material supplied to the main distillation column 4 is small and the operating pressure of the main distillation column 4 can be lowered, the fuel in the heating furnace 3 can be reduced.

Furthermore, since the operating pressure of the main distillation column 4 can be lowered, the stripper reboiler and reflux provided in each of the kerosene fraction extraction line 4b and the light oil fraction extraction line 4c connected to the side wall of the main distillation column 4 Each operating energy of the condenser and the cooler provided in the path can be kept small. Note that devices such as the stripper described here are not shown in FIG. Moreover, since the operating pressure of the main distillation column 4 is low, high separation performance can be expected in the main distillation column 4.
And since the liquid component (LPG and light naphtha fraction) from which the heavy naphtha fraction was separated in the preflash distillation tower 2 is supplied to the debutane tower 5, steam in the reboiler B3 of the debutane tower 5 or the like Energy consumption is reduced, and it is not necessary to provide a naphtha splitter after the debutane tower 5.

  Therefore, the system of the above-described embodiment requires a facility called a preflash distillation column 2 as compared with Patent Documents 1 and 2 described above, but as can be seen from the examples described later, Get smaller. In addition, since the operating energy is small, the size of the heating furnace and the cooler is reduced, so that a naphtha splitter is not necessary, and the construction cost can be kept low. Therefore, the system of the present invention is an extremely effective system for producing petroleum products using condensate as a raw material.

  The condensate processing system of the present invention (hereinafter referred to as “the present invention system”) is superior to the condensate processing technology (hereinafter referred to as “comparison system”) described in Patent Documents 1 and 2 described above. In order to demonstrate this, the operating energy was calculated for each of the inventive system and the comparative system. The system used for the calculation is shown in FIGS.

<Invention System>
FIG. 2 shows the system of the present invention, which is described more specifically than FIG. The parts corresponding to those in FIG. A1 is a condenser provided in the extraction line 2c at the top of the preflash distillation column 2, and A2 is a condenser provided in the extraction line 4a at the top of the main distillation column 4. A3 is a cooler provided in the reflux path at the top of the tower, A4 is a cooler provided in the reflux path of the kerosene fraction extraction area, and A5 is a cooler provided in the reflux path of the diesel oil fraction extraction area. is there. A6 is a condenser provided in the extraction line 5c at the top of the debutane tower 5.

  Reference numeral 41 denotes a stripper provided in a kerosene fraction extraction line 4 b from which a kerosene fraction is extracted from the main distillation column 4, and B 1 is a reboiler provided in a circulation path at the bottom of the stripper 41. Reference numeral 42 denotes a stripper provided in a light oil fraction extraction line 4 c from which a light oil fraction is extracted from the main distillation column 4, and B 2 denotes a reboiler provided in a circulation path at the bottom of the stripper 42.

  When using the system shown in FIG. 2 and supplying each batch of desulfurized condensate to the preflash distillation column 2 at 100,000 BPSD to obtain each product, the preflash distillation column 2, the main distillation column 4 and the debutane In each of the towers 5, the operating energy required for heating and the operating energy required for cooling were determined. The calculation results of the operating energy are shown in Table 1 after the description on the comparison system described later.

  In the preflash distillation column 2, the operating energy required for heating is the operating energy of the reboiler 22, and the operating energy required for cooling is the operating energy of the condenser A1. In the main distillation column 4, the operating energy required for heating is the operating energy of the heating furnace 3 and the reboilers B1 and B2, and the operating energy required for cooling is the operating energy of the condenser A2 and the coolers A3 to A5. In the debutane tower 5, the operating energy required for heating is the operating energy of the reboiler B3, and the operating energy required for cooling is the operating energy of the condenser A6.

<Comparison system>
As shown in FIG. 3, the comparative system is a system in which the condensate after batch desulfurization is heated by a heater 101 and then supplied to a main distillation column 102 which is an atmospheric distillation column and fractionated into each fraction. is there. The gas components obtained from the top of the main distillation column 102 are fractionated into LPG and naphtha fractions in the debutane tower 105 in the latter stage, and the naphtha fraction is separated from the light naphtha fraction and heavy by the naphtha splitter 106. It is fractionated into naphtha fractions.

  C1 is a condenser provided in the extraction line at the top of the main distillation column 102, C2 is a cooler provided in the reflux path at the top of the tower, and C3 is a cooler provided in the reflux path in the extraction region of the kerosene fraction. , C4 is a cooler provided in the reflux path of the extraction region of the light oil fraction. C5 is a condenser provided in the extraction line at the top of the debutane tower 105, and C6 is a condenser provided in the extraction line at the top of the naphtha splitter 106.

  Reference numeral 103 denotes a stripper provided in a kerosene fraction extraction line from which a kerosene fraction is extracted from the main distillation column 102, and reference numeral D <b> 1 denotes a reboiler provided in a circulation path at the bottom of the stripper 103. 104 is a stripper provided in a gas oil fraction extraction line from which a light oil fraction is extracted from the main distillation column 4, and D <b> 2 is a reboiler provided in a circulation path at the bottom of the stripper 104. D3 is a reboiler provided in the circulation path at the bottom of the debutanizer tower 105, and D4 is a reboiler provided in the circulation path at the bottom of the naphtha splitter 106.

When using the system shown in FIG. 3 and supplying each product after supplying the desulfurized condensate to the main distillation column 102 at 100,000 BPSD, the main distillation column 102, the debutane column 105, and the naphtha splitter 106 are obtained. In each, the operating energy required for heating and the operating energy required for cooling were determined. The calculation results of the operating energy are shown in Table 1 described later.
In the naphtha splitter 106, the operating energy required for heating is the operating energy of the reboiler D4, and the operating energy required for cooling is the operating energy of the condenser C6.

<Calculation result of operating energy>
Table 1 shows the calculation result of the operation energy in the system of the present invention and the calculation result of the operation energy in the system of the present invention.

As can be seen from the results in Table 1, the inventive system can reduce the energy required for heating by approximately 37% and the energy required for cooling by approximately 25% compared to the comparative system. Therefore, it is understood that the present invention has an effect that the operation energy can be greatly reduced as compared with the conventional system in which the condensate is desulfurized in a lump and then fractionated in the main distillation column.

Claims (6)

A system for processing condensate,
A desulfurization unit for hydrodesulfurizing condensate;
Condensate hydrodesulfurized by the desulfurizer is supplied, and includes gas components including liquefied petroleum gas and light naphtha fraction, and heavy naphtha fraction and heavy fraction having a higher boiling point than heavy naphtha fraction. A liquid component, a preflash distillation column for fractional distillation,
A reboiler for heating the liquid component at the bottom of the preflash distillation column;
A heating unit for heating the liquid component taken out from the bottom of the preflash distillation column to a temperature higher than the temperature of the reboiler;
A condensate treatment system comprising: a main distillation tower for fractionating the liquid component heated in the heating unit into at least a heavy naphtha fraction, a kerosene fraction and a light oil fraction.   2. The condensate treatment system according to claim 1, wherein the main distillation column fractionates the liquid component into a heavy naphtha fraction, a kerosene fraction, a light oil fraction, and a heavy residue.   The condensate treatment system according to claim 1, wherein the temperature of the reboiler is 200 ° C to 300 ° C.   The condensate treatment system according to claim 1, wherein a heating temperature by the heating unit is 250 ° C. to 350 ° C. The main distillation column is composed of a plate column,
2. The condensate treatment system according to claim 1, wherein a supply position of the liquid component in the main distillation column is lower than a lowermost tray.   The condensate treatment system according to claim 1, further comprising a distillation column for fractionating the gas component taken out from the preflash distillation column into a liquefied petroleum gas and a light naphtha fraction.

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