WO1986006739A1 - Distillation cut point control - Google Patents
Distillation cut point control Download PDFInfo
- Publication number
- WO1986006739A1 WO1986006739A1 PCT/US1986/000881 US8600881W WO8606739A1 WO 1986006739 A1 WO1986006739 A1 WO 1986006739A1 US 8600881 W US8600881 W US 8600881W WO 8606739 A1 WO8606739 A1 WO 8606739A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- stripper
- cut point
- liquid
- control
- efv
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G7/00—Distillation of hydrocarbon oils
- C10G7/12—Controlling or regulating
Definitions
- DISTILLATION CUT POINT CONTROL Field of the Invention This invention relates to removal of cuts from mixtures of liquids, and more particularly to cut point control in petroleum crude towers.
- said cut point may be controlled through use of a characteristic of the liquid in said bottom tray.
- said characteristic is the partial pressure of said liquid.
- said charac ⁇ teristic is the initial boiling point of the equilibrium flash vaporization curve ("IBP/EFV") of said liquid at atmospheric pressure.
- cut point I mean that temperature (in °F) on a true boiling point (“TBP") curve (i.e., a batch pro ⁇ cess curve of percent of mixture—e.g., crude oil—re ⁇ moved in a heavily refluxed tower versus temperature reached to achieve that removal at which a predetermined degree of separation is reached) .
- TBP true boiling point
- Drawings Fig. 1 is a diagrammatic view with respect to practice of the method.
- Fig. 2 is a pair of curves intersecting to give a cut point.
- Steps A crude tower of conventional arrangement, as shown in Fig. 1, and indicated generally at 10, and con ⁇ taining about fifty plates, was continuously supplied with heated crude oil through line 12. Emerging from tower 10 in order up its height were draw lines 14 (for atmospheric gas oil), 16 (for diesel oil), 18 (for kero ⁇ sene) , and 20 (for heavy naphtha) . Said draw lines fed respectively into strippers 22, 24, 26, and 28 above the top plate of each thereof (each stripper having about six plates) .
- composition rang ⁇ es desired to be manufactured would call for cut points between the atmospheric gas oil and diesel oil of 704°, between diesel oil and kerosene of 492°, and between kerosene and heavy naphtha of 322°.
- My invention was used to maintain and control at these predetermined cut points (all temperatures mentioned in this document Farenheit) each of the three.
- My control method was then used to regulate ac- tual cut point.
- the difference between this temperature and the IBP/EFV temperature gives a correction factor that may be used with the IBP/EFV temperature to provide the running (minute' by minute) cut point.
Abstract
Control of crude oil distillation columns. In particular, properties of the liquid in the bottom tray of a side stream stripping unit (22) associated with the crude distillation column (10) are monitored in order to control product drawn rates thereby maintaining desired product cut points. Preferably, partial pressures and initial boiling points of the equilibrium flash vaporization curve (''IBP/EFV'') are monitored in this control Scheme.
Description
DISTILLATION CUT POINT CONTROL Field of the Invention This invention relates to removal of cuts from mixtures of liquids, and more particularly to cut point control in petroleum crude towers.
Background of the Invention It has been known to correlate side draw temp¬ eratures with cut points through simultaneous monitoring of numerous tower parameters (e.g., Nelson, "Petroleum Refinery Engineering", McGraw-Hill, Fourth Ed. 1958, 473 ff).
Summary of the Invention I have discovered that the cut point between any heavier cut to be withdrawn and lighter material may be con- trolled based on parameters around simply the bottom tray of a stripper for said heavier cut.
In particular, I have discovered that said cut point may be controlled through use of a characteristic of the liquid in said bottom tray. In a preferred embodiment, said characteristic is the partial pressure of said liquid.
In a further preferred embodiment, said charac¬ teristic is the initial boiling point of the equilibrium flash vaporization curve ("IBP/EFV") of said liquid at atmospheric pressure.
By "cut point", I mean that temperature (in °F) on a true boiling point ("TBP") curve (i.e., a batch pro¬ cess curve of percent of mixture—e.g., crude oil—re¬ moved in a heavily refluxed tower versus temperature reached to achieve that removal at which a predetermined degree of separation is reached) .
Preferred Embodiment I turn now to a description of the drawings, and of a preferred embodiment of the invention. Drawings Fig. 1 is a diagrammatic view with respect to practice of the method.
Fig. 2 is a pair of curves intersecting to give a cut point. Steps A crude tower of conventional arrangement, as shown in Fig. 1, and indicated generally at 10, and con¬ taining about fifty plates, was continuously supplied with heated crude oil through line 12. Emerging from tower 10 in order up its height were draw lines 14 (for atmospheric gas oil), 16 (for diesel oil), 18 (for kero¬ sene) , and 20 (for heavy naphtha) . Said draw lines fed respectively into strippers 22, 24, 26, and 28 above the top plate of each thereof (each stripper having about six plates) . It was decided in advance that composition rang¬ es desired to be manufactured would call for cut points between the atmospheric gas oil and diesel oil of 704°, between diesel oil and kerosene of 492°, and between kerosene and heavy naphtha of 322°. My invention was used to maintain and control at these predetermined cut points (all temperatures mentioned in this document Farenheit) each of the three.
The invention may be explained in particular detail with respect to the cut point between diesel oil and kerosene.
At startup, temperature in the draw tray from
which draw line 16 emerged was monitored until about that expected to be associated with the desired cup point, about 515°.
My control method was then used to regulate ac- tual cut point.
The following measurements were taken, then, each minute:
(1) Steam flow to stripper 24 (Ibs./hr.)
(2) Diesel oil flow from bottom of stripper 24 (barrels/day)
(3) Temperature in diesel oil draw line 16
(4) Temperature of diesel oil flowing from bot¬ tom of stripper 24
(5) Pressure in stripper 24. (treated as that at draw tray from which draw line 16 emerges, and determined' by interpolating between bottom and top pressures of tower 10)
(6) Temperature of steam into stripper 24
(7) Pressure of steam into stripper 24. Using these seven measurements, together with constants from laboratory data to give specific heat, partial pres¬ sure of diesel oil ("liquid") in the vapor above the bot¬ tom plate of stripper 24 is obtained; this is then used to determine atmospheric pressure IBP/EFV of the diesel oil. In making this determination, constants are desirably used which from most recent (usually daily) laboratory data up¬ date the apex of the two-phase region triangle defined by plotting EFV's for various vaporization percentages as shown in Fig. 3B3.1 of API Technical Data Book (August, 1963) , pressure versus temperature graphs for each per¬ centage mixture being a straight line. (Since partial
pressure of the diesel oil and the temperature of the diesel oil on the bottom tray of stripper 24 define one point on the initial boiling point—i.e., 100% liquid, "IBP"—line and the apex the other, the atmospheric IBP/ EFV may be easily picked off.)
Once daily the laboratory supplied an ASTM curve of temperature versus percent, vaporized, for both the diesel oil and the kerosene. Using conventional conver¬ sions, these permitted establishment of true boiling point curves for each. Using these, plotted over widths reflect¬ ing their relative volumes (barrels/day) , and with kerosene curve flipped, all as shown in Fig. 2, an intersection re¬ sults at a temperature which is the cut point.
The difference between this temperature and the IBP/EFV temperature gives a correction factor that may be used with the IBP/EFV temperature to provide the running (minute' by minute) cut point.
If the measured cut point is not exactly that desired, the flow rates in draw lines 16 and 18 are ap- propriately varied, in equal but opposite amounts.
In the same manner, the cut point between atmos¬ pheric gas oil and diesel oil was controlled using strip¬ per 22 as the focus of control in the same way as was stripper 24 in the control above described, and, in the same way, the cut point between kerosene and heavy naphtha was controlled using stripper 26 as the focus of control. The cut point between heavy naphtha and light naphtha was controlled by prior art methods, although the method of my invention could of course have been used. ~-- Claims
Other embodiments of the invention within the
following claims will occur to those skilled in the art.
I claim:
Claims
1. The method of controlling the content of a draw from a distillation column which comprises monitor¬ ing a characteristic of contents of a stripper downstream of a draw.
2. The method of claim 1 in which said contents is that being withdrawn from said stripper.
3. The method of claim 1 in which said charac¬ teristic is the partial pressure of liquid on the bottom plate of said stripper.
4. The method of claim 3 in which another said characteristic is the IBP/EFV of said liquid at atmospher¬ ic pressure.
5. The method of claim 4 in which said liquid is a crude oil cut.
6. The method of claim 3- in which said"liquid is a crude oil cut.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE8686903039T DE3680636D1 (en) | 1985-05-03 | 1986-04-21 | REGULATION OF THE SEPARATION POINT IN DISTILLATION. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US73027785A | 1985-05-03 | 1985-05-03 | |
US730,277 | 1985-05-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1986006739A1 true WO1986006739A1 (en) | 1986-11-20 |
Family
ID=24934671
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1986/000881 WO1986006739A1 (en) | 1985-05-03 | 1986-04-21 | Distillation cut point control |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0221146B1 (en) |
JP (1) | JPS62501572A (en) |
AU (1) | AU591495B2 (en) |
CA (1) | CA1298233C (en) |
DE (1) | DE3680636D1 (en) |
WO (1) | WO1986006739A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7563752B2 (en) | 2002-08-05 | 2009-07-21 | Nippon Oil Corporation | Lubricating oil compositions |
US7612025B2 (en) | 2004-02-04 | 2009-11-03 | Nippon Oil Corporation | Lubricating oil composition |
US7625847B2 (en) | 2002-08-05 | 2009-12-01 | Nippon Oil Corporation | Lubricating oil compositions |
US7696137B2 (en) | 2002-08-27 | 2010-04-13 | Nippon Oil Corporation | Lubricating oil compositions |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6919366B2 (en) | 1998-05-22 | 2005-07-19 | Avanir Pharmaceuticals | Benzimidazole derivatives as modulators of IgE |
MXJL03000027A (en) | 2001-03-12 | 2004-04-30 | Avanir Pharmaceuticals | Benzimidazole compounds for modulating ige and inhibiting cellular proliferation. |
TWI276631B (en) | 2002-09-12 | 2007-03-21 | Avanir Pharmaceuticals | Phenyl-aza-benzimidazole compounds for modulating IgE and inhibiting cellular proliferation |
WO2004024655A2 (en) | 2002-09-12 | 2004-03-25 | Avanir Pharmaceuticals | Phenyl-indole compounds for modulating ige and inhibiting cellular proliferation |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3320158A (en) * | 1964-11-06 | 1967-05-16 | Phillips Petroleum Co | Crude oil fractionation method |
US3365386A (en) * | 1966-04-04 | 1968-01-23 | Phillips Petroleum Co | Process and apparatus for producing variable boiling point distillates |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4558423A (en) * | 1983-05-27 | 1985-12-10 | Phillips Petroleum Company | Utilization of an ASTM end point temperature for controlling a fractional distillation process |
JPS6038001A (en) * | 1983-08-09 | 1985-02-27 | Nippon Zeon Co Ltd | Controlling method of distillation tower |
-
1986
- 1986-04-21 JP JP50269486A patent/JPS62501572A/en active Granted
- 1986-04-21 DE DE8686903039T patent/DE3680636D1/en not_active Expired - Fee Related
- 1986-04-21 EP EP19860903039 patent/EP0221146B1/en not_active Expired
- 1986-04-21 WO PCT/US1986/000881 patent/WO1986006739A1/en active IP Right Grant
- 1986-04-21 AU AU58629/86A patent/AU591495B2/en not_active Ceased
- 1986-05-02 CA CA000508201A patent/CA1298233C/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3320158A (en) * | 1964-11-06 | 1967-05-16 | Phillips Petroleum Co | Crude oil fractionation method |
US3365386A (en) * | 1966-04-04 | 1968-01-23 | Phillips Petroleum Co | Process and apparatus for producing variable boiling point distillates |
Non-Patent Citations (2)
Title |
---|
Edminster, "Applied Hydrocarbon Thermodynamics" published 1981, Gulf publishing Co, USA, see pages 116-132. * |
See also references of EP0221146A4 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7563752B2 (en) | 2002-08-05 | 2009-07-21 | Nippon Oil Corporation | Lubricating oil compositions |
US7625847B2 (en) | 2002-08-05 | 2009-12-01 | Nippon Oil Corporation | Lubricating oil compositions |
US7696137B2 (en) | 2002-08-27 | 2010-04-13 | Nippon Oil Corporation | Lubricating oil compositions |
US7612025B2 (en) | 2004-02-04 | 2009-11-03 | Nippon Oil Corporation | Lubricating oil composition |
Also Published As
Publication number | Publication date |
---|---|
EP0221146B1 (en) | 1991-07-31 |
AU5862986A (en) | 1986-12-04 |
DE3680636D1 (en) | 1991-09-05 |
AU591495B2 (en) | 1989-12-07 |
CA1298233C (en) | 1992-03-31 |
EP0221146A4 (en) | 1987-08-12 |
JPH0470352B2 (en) | 1992-11-10 |
JPS62501572A (en) | 1987-06-25 |
EP0221146A1 (en) | 1987-05-13 |
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