JPS62501572A - Control of distillation cut point - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Distillation point control field of invention The present invention relates to the removal of distillate fractions from liquid mixtures, and more particularly to Regarding distillation point control.

Background of the invention The temperature of the side draw liquid is set to the cut points. ) and by monitoring a large number of tower parameters simultaneously. [For example, McGraw-Hill Co. (McGraw-Hi I1) ) Published by Nelson 7 (Nelson), 1 Petroleum Refinery Engineering (Petroleum Refinery Engineeri) ng)'', 4th edition, pp. 476 et seq. (1958)].

Summary of the invention The inventor has discovered that the distillation point between any heavy fraction and light fraction to be drawn is proportional to its weight. Can be controlled based on the parameters around the bottom tray of the distillate strip. I just discovered this.

In particular, the inventor has determined that the distillation point can be determined by using the properties of the liquid in the bottom tray. I discovered that I can control it.

In a preferred embodiment, the characteristic is the partial pressure of the liquid.

In a further preferred embodiment, the characteristic of the seventh characteristic is the equilibrium flash gas of the liquid. quilibrium flash vaporization curve) is the initial boiling point ("IBP/EFV") at atmospheric pressure.

The "distillation point" is the true boiling point (TBP) curve (that is, the mass reflux column ly reluxed tower), the mixture to be removed, e.g. Batch processing of the percentage of oil versus the temperature reached to reach a given degree of separation to achieve its removal. 7's initial boiling point temperature ('F) on the curve).

Preferred embodiment Next, drawings and description of preferred embodiments of the present invention will be provided.

drawing FIG. 1 is a schematic diagram relating to the implementation of this method.

Figure 2 shows a pair of intersecting curves giving the distillation point.

Process A conventional crude oil column arrangement is shown in FIG. The tower is generally indicated by 10. It includes approximately 50 shelves. Column 10 receives heated crude oil through line 12. Continuously supplied. From the tower 10, a drawing line 14 (normal pressure light oil (for atmospheric gas oil), 16 (for diesel oil) , 18 (for kerosene) and 20 (for heavy naphtha). These drawer lines are the top plays of strippers 22, 24, 26 and 28 respectively. (each stripper has approximately 6 shelves).

The target composition range to be produced has a distillation point between atmospheric gas oil and diesel oil. 70/I', 492° as the distillation point between diesel oil and kerosene, and kerosene and ■ It was previously determined that 622° was required as the distillation point between the naphtha and the naphtha. . The present invention can be applied to each of these six predetermined distillation points (temperature is herein referred to as total distillation point). It was used to maintain and control the

The invention will be described in particular detail with respect to the distillation point between diesel oil and kerosene.

First, check the temperature in the drawer tray from which the drawer line comes out until the temperature is desired. The temperature was monitored until it appeared to be associated with a distillation point of approximately 515°.

The precise distillation point was then adjusted using the control method of the present invention.

The following measurements were taken (each minute): (1) Steam flow to the stripper 24! (bond/time), (2) strip The flow rate of diesel oil coming out of the bottom of the tower 24 (7 barrel days), (3) Temperature inside the diesel oil draw line 16, (4) Tower of the stripper 24 temperature of the diesel oil flowing out from the bottom; (5) pressure inside the stripper 24 (drawer Treated similarly to the partial pressure in the drawer tray from which line 16 exits, and the column 10 (6) Stripper 24 (7) the pressure of the steam entering the stripper 24;

Using these seven measured values together with the constant giving the specific heat obtained from the experimental data, Partial pressure of diesel oil (“liquid”) in the vapor above the bottom shelf of stripper 24 ? obtain. Next, use this partial pressure to determine the atmospheric pressure IBP/EFV of diesel oil. Set. In making this decision, we consider various aspects of the latest experimental data (usually taken daily). API Technical Data Book (AIP) Technical Data Book) (August 1963), 3B3. of the two-phase region triangle defined by plotting as shown in 1. It is preferable to use constants that update the vertices. In this triangle, the mixture of each proportion The graph of pressure versus temperature for an object is a straight line. (Stripper 24 bottom training - The partial pressure and temperature of the diesel oil above are the initial boiling point...that is, 100% liquid. "IBP-..." line and one point on the other vertex is defined. Atmospheric pressure IBP/E FV can be easily installed. ) once a day for both easel oil and kerosene. The ASTM curve of temperature versus vaporization rate was obtained through several experiments.

True boiling point curves were established for each using normal conversion ratios. these plotted over a width reflecting the relative capacity of the two (7 days barrel), and for kerosene I drew a curve regarding.

The arrangement is as shown in FIG. The intersection of the curves is the temperature of the distillation point.

The difference between this temperature and the IBP/EFV temperature can be used in conjunction with the IBP/EFV temperature to gives a correction factor by which the minute-by-minute distillation point can be obtained.

If the measured distillation point is not exactly as desired, the withdrawal lines 16 and 18 Appropriately change the flow rates inside by equal but opposite amounts.

In the same way, the distillation point between normal pressure gas oil and diesel oil can also be adjusted by stripping in the above control. Controlled in the same way as Par 24 using Stripper 22 as the focus of control. . In the same way, the distillation point between kerosene and heavy naphtha can also be focused on stripping. It was controlled using a par of 26. The distillation point between heavy naphtha and light naphtha is determined by the conventional method. controlled. However, the method of the present invention can of course also be used.

The scope of the claims Other aspects of the invention that fall within the scope of the following claims will be apparent to those skilled in the art.

$1 Diagram Handbook Supplementary Book Commissioner of the Patent Office Kuro [■ Akio 1.Display of the incident PCT/US 86100881 , name of invention Control of distillation cut point 3.11n Person who corrects Relationship to the incident: Patent applicant address Name: Foxboro Company 4. Agent 5.? ltl positive object 6. Contents of amendment (Attachment) (1) [Title of the invention] in the specification is amended to "control of distillation cut point."

(2) Scope of Claims of the Specification] shall be amended as follows.

(1) Introduction line, steam introduction line for stripping, multiple trays and The bottom of the first distillation column, which has a Bircht vapor removal line and where the distillation process is carried out. By controlling the composition of the desired liquid product in the product removal line located in measuring the partial pressure of the components evaporated from the liquid at the bottom of the column; Monitor the liquid temperature at the bottom of the column; use partial pressure and temperature to monitor the liquid temperature at the bottom of the column. Obtain the initial boiling point (IBL); compare the IBP with the desired composition; and achieve the LI goal. A control method characterized in that the distillation process is adjusted to approximate

(2) The first distillation column receives the draw liquid (drau+) from the second distillation column. the second distillation column is a multi-draw column (mu ltidraw column), and the evaporated components are transferred to the overhead vapor. 2. The method of claim 1, wherein the method is returned to the multi-draw column in a removal line.

(3) A claim in which the IBP is an IBP of an equilibrium flash evaporation (EFV) curve. The method described in box 1.

(4) Claim 3, wherein IBr' of the EFV is IBP at atmospheric pressure. the method of.

(5) A claim in which the adjustment consists of 371 adjusting the flow in the various lines. The method described in Section 1 of Box tIS.

(6) Having multiple introduction lines for receiving the drawn liquid from the multi-draw tower. further stripper column, and similar measurements in this additional stripper column. further carrying out process, monitoring, obtaining IBP, comparison and adjustment steps; 3. A method according to claim 2, comprising:

(7) The ifl! of claims consisting of adjusting the flow in the various lines. The method described in Range 16.

(8) The method according to claim PA2, wherein the multi-draw tower receives crude oil. ” (3) Page 1 of the specification, lines 7, 16, and 24; Page 2, lines 9, 21, and 21-22 Lines and 22nd lines; 'J4f'jUU62-501572 (4) Page 3, lines 1 and 4 and line 6; and page t54, lines 12, 15, 17, 20, 23 and 24 Correct the "distillation point" of each with the "force/nod point".

(4) On page 1 of the same ptS, lines 24-25, replace [in a large amount...] with a large amount of reflux. amended to ``at the tower (1+eavily reflexed tower)''.

(5) Change the “Batch Processing Curve” in line 2 on page 12 to “Tsuchi Process Curve” in parentheses. to correct.

(6) On page 3, line 7, “Took (each minute):” was replaced with “Took every minute:” Correct.

(Ma) The description is amended as follows.

Page line Before correction After correction 〃15〃Light distillate〃Light substances 〃22〃Evaporation curve〃Evaporation curve.

2 24 Each fraction, each cut point 3 3 Extraction line Extraction line 1 6.14 Same as partial pressure, as pressure that's all international search report

Claims (6)

[Claims] 1. consisting of monitoring the characteristics of the contents of the stripper downflow of the withdrawal liquid; A method for controlling the content of a draw liquid from a distillation column, characterized in that: 2. Claim 1, wherein the contents are extracted from the stripper. The method described in section. 3. Claim 1, wherein said characteristic is the partial pressure of the liquid on the bottom shelf of said stripper. Method described. 4. Claim 3, wherein the characteristic is IBP/EFV of the liquid at atmospheric pressure. How to put it on. 5. Claim 4, wherein the liquid is a crude oil cut. the method of. 6. 4. The method of claim 3, wherein said liquid is a crude oil fraction.