Claims
- 1. A control system for a furfural refining unit receiving charge oil and furfural solvent, one of which is maintained at a fixed flow rate while the flow rate of the other is controlled by the control system, treats the received charge oil with the received furfural to yield means for sampling the charge oil and providing a signal API corresponding to the API gravity of the charge oil, flash point analyzer means for sampling the charge oil and providing a signal FL corresponding to the flash point temperature of the charge oil, viscosity analyzer means for sampling the charge oil and providing signals KV.sub.150 and KV.sub.210 corresponding to the kinematic viscosities, corrected to 150.degree. F. and 210.degree. F., respectively, sulfur analyzer for sampling the charge oil and providing a signal S corresponding to the sulfur content of the charge oil, a refractometer samples the charge oil and provides a signal RI corresponding to the refractive index of the charge oil, flow rate sensing means for sensing the flow rates of the charge oil and of the furfural and providing signals CHG and SOLV, corresponding to the charge flow rate and the furfural flow rate, respectively, means for sensing the temperature of the extract-mix and providing a corresponding signal T, and control means connected to all of the analyzer means, the refractometer, and to all the sensing means for controlling the other flow rate of the charge oil and the furfural flow rates in accordance with signals API, FL, KV.sub.150, KV.sub.210, S, RI, CHG, T and SOLV.
- 2. A system as described in claim 1, in which the charge oil may be light sweet charge oil having a sulfur content equal to or less than a predetermined sulfur content and having a kinematic viscosity, corrected to a predetermined temperature, equal to or less than a first predetermined kinematic viscosity, light sour charge oil having a sulfur content greater than the predetermined sulfur content and having a kinematic viscosity, corrected to the predetermined temperature, equal to or less than the first predetermined kinematic viscosity, medium sweet charge oil having a sulfur content equal to or less than the predetermined sulfur content and having a kinematic viscosity, corrected to the predetermined temperature, greater than the first predetermined kinematic viscosity but equal to or less than a second predetermined kinematic viscosity, medium sour charge oil having a sulfur content greater than the predetermined sulfur content and having a kinematic viscosity, corrected to the predetermined temperature, greater than the first predetermined kinematic viscosity but equal to or less than the second predetermined kinematic viscosity, heavy sweet charge oil having a sulfur content equal to or less than the predetermined sulfur content and having a kinematic viscosity, corrected to the predetermined temperature, greater than the second predetermined kinematic viscosity, or heavy sour charge oil having a sulfur content greater than the predetermined sulfur content and having a kinematic viscosity, corrected to the predetermined temperature, greater than the second predetermined kinematic viscosity; and the control means includes a plurality of J signal means, each J signal means providing a signal J representative of a furfural dosage for a corresponding type of charge oil, selection means connected to the J signal means, to the viscosity analyzing means and to the sulfur analyzing means for selecting on of the J signals in accordance with one of the kinetic viscosity signals from the viscosity analyzer means and signal S and providing the selected J signal, control signal means connected to the selection means and to the flow rate sensing means for providing a control signal in accordance with the selected J signal and one of the sensed flow rate signals, and apparatus means connected to the control network means for controlling the one flow rate of the charge oil and furfural flow rates in accordance with the control signal.
- 3. A system as described in claim 2, in which the control means includes VI signal means connected to the viscosity analyzer means for providing a signal VI corresponding to the viscosity index of the charge oil in accordance with kinematic viscosity signals KV.sub.150 and KV.sub.210 ; SUS.sub.210 signal means connected to the viscosity analyzer means for providing a signal SUS.sub.210 corresponding to the charge oil viscosity in Saybolt Universal Seconds corrected to 210.degree. F; W signal means connected to the viscosity analyzer means, to the gravity analyzer means and to the sulfur analyzer means for providing a signal W corresponding to the wax content of the charge oil in accordance with signals KV.sub.210, API and S, first A signal means connected to the viscosity analyzer means, to the sulfur analyzer means, to the flash point temperature analyzer means, to the gravity analyzer means and to the VI signal means for providing a first signal A corresponding to an interim factor A in accordance with signals KV.sub.210, S, FL, API and VI; second A signal means connected to the viscosity analyzer means, to the gravity analyzer means and to the flash point temperature analyzer means for providing a second signal A corresponding to an interim factor A in accordance with signals KV.sub.210, API and FL; third A signal means connected to the gravity analyzer means, to the viscosity analyzer means, to the sulfur analyzer means, to the flash point temperature analyzer means and to the VI signal means for providing a third signal A corresponding to an interim factor A in accordance with signals KV.sub.210, S, API, VI and FL; first .DELTA.VI signal means connected to the viscosity analyzer means, to the gravity analyzer means, to the flash point temperature analyzer means, to the VI signal means and to the SUS.sub.210 signal means and receiving a direct current voltage VI.sub.RP corresponding to the viscosity index of the refined oil at the predetermined temperature for providing a first signal .DELTA.VI in accordance with signals KV.sub.210, API, FL, VI and SUS.sub.210 and voltage VI.sub.RP ; second .DELTA.VI signal means connected to the gravity analyzer means, to the flash point temperature analyzer means, to the refractometer, to the VI signal means, to the W signal means and to the SUS.sub.210 signal means and receiving voltage VI.sub.RP for providing a second signal .DELTA.VI corresponding to the change in viscosity index in accordance with signals VI, W, API, FL, RI, SUS.sub.210 and voltage VI.sub.RP ; third .DELTA.VI signal means connected to the viscosity analyzer means, to the gravity analyzer means, to the flash point temperature analyzer means, to the VI signal means, the W signal means and the SUS.sub.210 signal means and receiving voltage VI.sub.RP for providing a third signal .DELTA.VI corresponding to the change in viscosity index in accordance with signals KV.sub.210, API, VI, FL, W and SUS.sub.210 and voltage VI.sub.RP ; and the plurality of J signal means includes first J signal means connected to the first .DELTA.VI signal means, to the first A signal means, to the temperature sensing means and to the selection means for providing a first J signal to the selection means corresponding to a furfural dosage for light sweet charge oil in accordance with the first .DELTA.VI signal, the first signal A and signal T, second J signal means connected to the first .DELTA.VI signal means, to the first A signal means, to the temperature sensing means and to the selection means for providing a second J signal to the selection means corresponding to the furfural dosage for light sour charge oil in accordance with the first signal .DELTA.VI, the first signal A and signal T, third J signal means connected to the second .DELTA.VI signal means, to the second A signal means, to the temperature sensing means and to the selection means for providing a third J signal to the selection means corresponding to the furfural dosage for medium sweet charge oil in accordance with the second signal .DELTA.VI, the second signal A, and signal T, fourth J signal means connected to the second .DELTA.VI signal means, to the temperature sensing means and to the selection means for providing a fourth J signal to the selection means corresponding to the furfural dosage for medium sour charge oil in accordance with the second signal .DELTA.VI and signal T, fifth J signal means connected to the third .DELTA.VI signal means, to the third A signal means, to the temperature sensing means and to the selection means for providing a fifth signal J to the selection means corresponding to the furfural dosage for heavy sweet charge oil in accordance with the third signal .DELTA.VI, the third signal A and signal T, and sixth J signal means connected to the third .DELTA.VI signal means, to the third A signal means, to the temperature sensing means and to the selection means for providing a sixth J signal to the selection means in accordance with the third signal .DELTA.VI, the third signal A and signal T.
- 4. A system as described in claim 3 in which the SUS.sub.210 signal means includes SUS signal means connected to the viscosity analyzer means, and receiving direct current voltages C.sub.5 through C.sub.12 for providing a signal SUS corresponding to an interim factor SUS in accordance with signal KV.sub.210, voltages C.sub.5 through C.sub.12 and the following equation:
- SUS=C.sub.5 (KV.sub.210)+[C.sub.6 +C.sub.7 (KV.sub.210)]/[C.sub.8 +C.sub.9 (KV.sub.210)+C.sub.10 (KV.sub.210).sup.2 +C.sub.11 (KV.sub.210).sup.3 ](C.sub.12),
- where C.sub.5 through C.sub.12 are constants; and SUS.sub.210 network means connected to the SUS signal means and to all the .DELTA.VI signal means and receiving direct current voltages C.sub.13 through C.sub.16 for providing signal SUS.sub.210 to all the .DELTA.VI signal means in accordance with signal SUS, voltages C.sub.13 through C.sub.16 and the following equation:
- SUS.sub.210 =[C.sub.13 +C.sub.14 (C.sub.15 -C.sub.16)]SUS,
- where C.sub.13 through C.sub.16 are constants.
- 5. A system as described in claim 4 in which the W signal means further receives direct current voltages C.sub.43 through C.sub.49 and provides signal W in accordance with signals API, KV.sub.210 and S, voltages C.sub.43 through C.sub.49, and the following equation:
- W=C.sub.43 -C.sub.44 API+C.sub.45 /KV.sub.210 -C.sub.46 S+C.sub.47 (API).sup.2 -C.sub.48 API/KV.sub.210 +C.sub.49 (S)(API).sub.s
- where C.sub.43 through C.sub.49 are constants.
- 6. A system as described in claim 5 in which the VI signal means includes K signal means receiving direct current voltages C.sub.2, C.sub.3, C.sub.4 and T.sub.150 for providing a signal K.sub.150 corresponding to the kinematic viscosity of the charge oil corrected to 150.degree. F. in accordance with voltages C.sub.2, C.sub.3, C.sub.4 and T.sub.150, and the following equation:
- K.sub.150 =[C.sub.2 -In(T.sub.150 +C.sub.3)]/C.sub.4,
- where C.sub.2 through C.sub.4 are constants, and T.sub.150 corresponds to a temperature of 150.degree. F.; H.sub.150 signal means connected to the viscosity analyzer means and receiving a direct current voltage C.sub.1 for providing a signal H.sub.150 corresponding to a viscosity H value for 150.degree. F. in accordance with signal KV.sub.150 and voltage C.sub.1 in the following equation:
- H.sub.150 =lnln(KV.sub.150 +C.sub.1),
- where C.sub.1 is a constant; H.sub.210 signal means connected to the viscosity analyzer means and receiving voltage C.sub.1 for providing signal H.sub.210 corresponding to a viscosity H value for 210.degree. F. in accordance with signal KV.sub.210, voltage C.sub.1 and the following equation:
- H.sub.210 =lnln(KV.sub.210 +C.sub.1),
- H.sub.100 signal means connected to the K signal means, to the H.sub.150 signal means and the H.sub.210 signal means for providing a signal H.sub.100 corresponding to a viscosity H value for 100.degree. F., in accordance with signals H.sub.150, H.sub.210 and K.sub.150 and the following equation:
- H.sub.100 =H.sub.210 +(H.sub.150 -H.sub.210)/K.sub.150
- kv.sub.100 signal means connected to the H.sub.100 signal means and receiving voltage C.sub.1 for providing a signal KV.sub.100 corresponding to a kinematic viscosity for the charge oil corrected to 100.degree. F. in accordance with signal H.sub.100, voltage C.sub.1, and the following equation:
- KV.sub.100 =exp[exp(H.sub.100)]-C.sub.1,
- and VI memory means connected to the KV.sub.100 signal means and to the viscosity analyzer means having a plurality of signals stored therein, corresponding to different viscosity index and controlled by signals KV.sub.100 and KV.sub.210 to select a stored signal and providing the selected stored signal as signal VI.
- 7. A system as described in claim 6 in which the first A signal means also receives direct current voltages C.sub.24 through C.sub.31 and provides the first signal A in accordance with signals S, KV.sub.210, API, VI and FL, voltages C.sub.24 through C.sub.31 and the following equation:
- A=C.sub.24 -C.sub.25 (S)-C.sub.26 (S).sup.2 +C.sub.27 (KV.sub.210)(API)-C.sub.28 (KV.sub.210)(VI)-C.sub.29 (FL)(API)+C.sub.30 (FL)(S)+C.sub.31 (FL)(VI),
- where C.sub.24 through C.sub.31 are constants.
- 8. A system as described in claim 7 in which the second A signal means also receives direct current voltages C.sub.55 through C.sub.56 and provides the second A signal in accordance with signals API, FL, and KV.sub.210, voltages C.sub.55 through C.sub.57 and the following equation:
- A=C.sub.55 -C.sub.50 (API)+C.sub.57 (FL)(KV.sub.210),
- where C.sub.55 through C.sub.57 are constants.
- 9. A system as described in claim 10 in which the third A signal means also receives direct current voltages C.sub.74 through C.sub.79 and provides the third signal A in accordance with signals KV.sub.210, S, FL, and API, voltages C.sub.74 through C.sub.79, and the following equation:
- A=C.sub.74 -C.sub.75 (KV.sub.210).sup.2 +C.sub.76 (S)+C.sub.77 (FL).sup.2 -C.sub.78 (FL)(API)-C.sub.79 (KV.sub.210)(S),
- where C.sub.74 through C.sub.79 are constants.
- 10. A system as described in claim 9 in which the first .DELTA.VI signal means includes VI.sub.DWC.sbsb.O signal means connected to the flash point temperature analyzer means, to the viscosity analyzer means and to the gravity analyzer means, and to the VI signal means, and receiving direct current voltages C.sub.17 through C.sub.20 for providing a first signal VI.sub.DWC.sbsb.O corresponding to the viscosity index of the dewaxed charge oil for 0.degree. F. in accordance with signals FL, VI, KV.sub.210 and API, voltages C.sub.17 through C.sub.20 and the following equation:
- VI.sub.DWC.sbsb.O =C.sub.17 -C.sub.18 (FL)+C.sub.19 (VI)+C.sub.20 (KV.sub.210)(API),
- where C.sub.17 through C.sub.20 are constants; VI.sub.DWC.sbsb.P signal means connected to the first VI.sub.DWC.sbsb.O signal means and to the SUS.sub.210 signal means, and receiving direct current voltages C.sub.21 through C.sub.23 and Pour, providing a signal VI.sub.DWC.sbsb.P corresponding to the viscosity index of the dewaxed charge oil at the predetermined temperature, in accordance with signals VI.sub.DWC.sbsb.O and SUS.sub.210, voltages C.sub.21 through C.sub.23 and Pour, and the following equation:
- VI.sub.DWC.sbsb.P =VI.sub.DWC.sbsb.O +(POUR)[C.sub.21 -C.sub.22 lnSUS.sub.210 +C.sub.23 (lnSUS.sub.210).sup.2 ],
- where Pour is the pour point of the dewaxed product and C.sub.21 through C.sub.23 are constants; subtracting means connected to the first VI.sub.DWC.sbsb.P means and to the first and second J signal means and receiving voltage VI.sub.RP for kinematic voltage VI.sub.RP from signal VI.sub.DWC.sbsb.P to provide the first .DELTA.VI signal to the first and second J signal means.
- 11. A system as described in claim 10 in which the second .DELTA.VI signal means includes a second VI.sub.DWC.sbsb.O signal means connected to the gravity analyzer means, the flash point temperature analyzer means, the refractometer, the VI signal means and the W signal means, and receives direct current voltages C.sub.50 through C.sub.54 and provides a second VI.sub.DWC.sbsb.O signal in accordance with signals RI, VI, FL, W and API, voltages C.sub.50 through C.sub.54 and the following equation:
- VI.sub.DWC.sbsb.O =C.sub.50 -C.sub.51 RI+C.sub.52 (RI)(VI)+C.sub.53 (FL)(API)-C.sub.54 (W)(VI),
- where C.sub.50 through C.sub.54 are constants; a second VI.sub.DWC.sbsb.P signal means connected to the second VI.sub.DWC.sbsb.O signal means and to the SUS.sub.210 signal means for providing a second VI.sub.DWC.sbsb.P signal in accordance with signals SUS.sub.210 and VI.sub.DWC.sbsb.O, voltages C.sub.21 through C.sub.23 and Pour, and the following equation:
- VI.sub.DWC.sbsb.p =VI.sub.DWC.sbsb.O +(POUR)[C.sub.21 -C.sub.22 lnSUS.sub.210 +C.sub.23 (lnSUS.sub.210).sup.2 ],
- and second subtracting means connected to the third and fourth J signal means and to the second VI.sub.DWC.sbsb.P signal means and receiving voltage VI.sub.RP for subtracting signal VI.sub.DWC.sbsb.P from voltage VI.sub.RP to provide the second .DELTA.VI signal to the third and fourth J signal means.
- 12. A system as described in claim 11 in which the third .DELTA.VI signal means includes a third VI.sub.DWC.sbsb.O signal means connected to the viscosity analyzer means, to the gravity analyzer means, to the flash point temperature analyzer means, to the VI signal means, to the W signal means and receiving direct current voltages C.sub.67 through C.sub.73 for providing a third signal VI.sub.DWC.sbsb.O in accordance with signals KV.sub.210, VI, API, FL and W, voltages C.sub.67 through C.sub.73, and the following equation:
- VI.sub.DWC.sbsb.O =-C.sub.67 +C.sub.68 (KV.sub.210).sup.2 +C.sub.69 (VI)-C.sub.70 (API)(VI)+C.sub.71 (API).sup.2 +C.sub.72 (FL)(VI)-C.sub.73 (W)(KV.sub.210),
- where C.sub.67 through C.sub.73 are constants; a third VI.sub.DWC.sbsb.P signal means connected to the third VI.sub.DWC.sbsb.O signal means and to the SUS.sub.210 signal means, and receiving direct current voltages C.sub.21 through C.sub.23 and Pour, for providing a third signal VI.sub.DWC.sbsb.P in accordance with signal VI.sub.DWC.sbsb.O and SUS.sub.210, voltages C.sub.21 through C.sub.23, and Pour, and the following equation:
- VI.sub.DWC.sbsb.P =VI.sub.DWC.sbsb.O +(POUR)[C.sub.21 -C.sub.22 lnSUS.sub.210 +C.sub.23 (lnSUS.sub.210).sup.2 ],
- and third subtracting means connected to the third VI.sub.DWC.sbsb.P signal means and to the fifth and sixth J signal means and receiving direct voltage VI.sub.RP for subtracting the third signal VI.sub.DWC.sbsb.P from voltage VI.sub.RP to provide the third .DELTA.VI signal to the fifth and sixth J signal means.
- 13. A system as described in claim 12 in which flow rate of the charge oil is controlled and the flow of the furfural is maintained at a constant rate and the control signal means receives signal SOLV from the flow rate sensing means, the selected J signal from the selection means and a direct current voltage corresponding to a value of 100 and provides a signal C to the apparatus means corresponding to a new charge oil flow rate in accordance with the selected J signal, signal SOLV and the received voltage and the following equation:
- C=(SOLV)(100)/J,
- so as to cause the apparatus means to change the charge oil flow to the new flow rate.
- 14. A system as described in claim 12 in which the controlled flow rate is the furfural flow rate and the flow of the charge oil is maintained constant, and the control signal means is connected to the sensing means, to the selection means and receives a direct current voltage corresponding to the value of 100 for providing a signal SO corresponding to a new furfural flow rate in accordance with signals CHG and the selected J signal and the received voltage, and the following equation:
- SO=(CHG)(J)/100,
- so as to cause the furfural flow to change to the new flow rate.
- 15. A control system as described in claim 12 in which the first J signal means also receives direct current voltages C.sub.32 through C.sub.39 and provides the first J signal in accordance with signal T, the first A signal and the first .DELTA.VI signal, voltages C.sub.32 through C.sub.39 and the following equation:
- J={{C.sub.32 -C.sub.33 A+{[C.sub.33 A-C.sub.32 ].sup.2 -4[C.sub.34 -C.sub.35 A][-C.sub.36 +C.sub.37 .sqroot.T-C.sub.38 (A)(.sqroot.T)-.DELTA.VI]}.sup.1/2 }/2[C.sub.34 -C.sub.35 (A)]}.sup.2,
- where C.sub.32 through C.sub.39 are constants; the second J signal means also receives direct current voltages C.sub.39 through C.sub.42 and provides the second J signal in accordance with signal T, and the first .DELTA.VI signal, voltages C.sub.39 through C.sub.42 and the following equation:
- J={{-C.sub.39 +{(C.sub.39).sup.2 -4(C.sub.40)(T)[-C.sub.41 +C.sub.42 T-.DELTA.VI]}.sup.1/2 }/2(C.sub.40 T)}.sup.2,
- where C.sub.39 through C.sub.42 are constants; the third J signal means also receives direct current voltages C.sub.58 through C.sub.61 and provides the third J signal in accordance with signal T, the second A signal and the second .DELTA.VI signal, voltages C.sub.58 through C.sub.61 and the following equation:
- J={{-C.sub.58 A+{(C.sub.58 A).sup.2 -4C.sub.59 A(C.sub.60 +C.sub.61 .sqroot.T-.DELTA.VI)}.sup.1/2 }/2C.sub.59 A}.sup.2,
- where C.sub.58 through C.sub.61 are constants; the fourth J signal means also receives direct current voltages C.sub.62 through C.sub.66 and provides the fourth J signal in accordance with signal T, the second A signal and the second .DELTA.VI signal, voltages C.sub.62 through C.sub.66 and the following equation:
- J={{-C.sub.62 +{(C.sub.62).sup.2 -4(-C.sub.63)[C.sub.64 .sqroot.T+C.sub.65 (.sqroot.T)(A)-C.sub.66 -.DELTA.VI]}.sup.1/2 }/2C.sub.63 }.sup.2,
- where C.sub.62 through C.sub.66 are constants; the first J signal means also receives direct current voltages C.sub.80 through C.sub.83 and provides the fifth J signal in accordance with signal T, the third A signal and the third .DELTA.VI signal, voltages C.sub.80 through C.sub.83 and the following equation:
- J=(.DELTA.VI-C.sub.80 -C.sub.81 .sqroot.T)/[-C.sub.82 T+C.sub.83 (A)(T)],
- where C.sub.80 through C.sub.83 are constants; the sixth J signal means also receives direct current voltages C.sub.84 through C.sub.87 and provides the sixth J signal in accordance with signal T, the third A signal and the third .DELTA.VI signal, voltages C.sub.81 through C.sub.87 and the following equation:
- J={{-C.sub.84 A+{[C.sub.84 (A)].sup.2 -4[C.sub.85 (A)(T)][-C.sub.86 +C.sub.87 (A)(.sqroot.T)-.DELTA.VI]}.sup.1/2 }/2[C.sub.85 (A)(T)]}.sup.2,
- where C.sub.84 through C.sub.87 are constants.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation as to all subject matter common to U.S. application Ser. No. 851,999 filed Nov. 16, 1977, now abandoned, by Avilino Sequeira, Jr., John D. Begnaud and Frank L. Barger, and assigned to Texaco Inc., assignee of the present invention, and a continuation-in-part for additional subject matter.
US Referenced Citations (4)
Continuations (1)
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Number |
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851999 |
Nov 1977 |
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