Means and method for achieving an optimum acid strength for an alkylation unit

Claim 3

A system as described in claim 1 in which the control signal means includes means for providing signals corresponding to an acid strength A2 greater than the sensed acid strength A1, to an acid strength A3 less than the sensed acid strength A1, and to a reference acid strength A90; means connected to the flow rate sensing means, olefin sensing means, to the acid strength sensing means and to the economic value sensing means for providing signals corresponding to anticipated changes p2 and p3 in profit associated with the acid strnegths A2 and A3, respectively, in accordance with the acid strength A1, A2, A3 and A90 signals, the acid flow rate signal, the bottoms product flow rate signal, and the economic value signals, and a network connected to the profit change signal means, to the acid strength sensing means, to the control means and to the acid strength signal means for providing a signal, corresponding to a desired acid strength, to the control means as the control signal in accordance with the acid strength A1, A2 and A3 signals and the profit change p2 and p3 signals.

Claim 4

A system as described in claim 2 in which the profit change signal means includes means connected to the economic value signal means and receiving signals corresponding to octane adder factors theta 1, theta 2 and theta 3, to acid rates AR1, AR2 and AR3 and to an alkylate rate ALR for providing the p2 and p3 signals in accordance with the economic value signals, the received signals and the following equations: p2 ( phi 2 - phi 1)(ALR)(VO) - (AR1- AR2)(VA) and p3 ( phi 3 - phi 1)(ALR)(VO) - (AR1- AR2)(VA), where phi 1, phi 2 and phi 3 are the octane adder factors associated with the sensed acid strength A1 and the predetermined acid strengths A2 and A3, respectively, and where AR1, AR2 and AR3 are the acid rates associated with the sensed acid strength A1 and the predetermined acid strength A2 and A3, respectively; rate signal means connected to the flow rate sensing means, to the acid strength sensing means, to the aLkylate sensing means, to the acid strength signal means, and to the p2- p3 signal means for providing the ALR, AR1, AR2 and AR3 rate signals to the p2-p3 signal means in accordance with the signals from the flow rate sensing means and the acid strength A1, A2, A3 and A90 signals; and octane adder factor means connected to the acid strength sensing means, to the acid strength signal means, to the olefin sensing means and to the circuit and receiving direct current voltages corresponding to constants Kf, Kg and Kh for providing the octane adder factors phi 1, phi 2 and phi 3 signals to the circuit in accordance with the sensed acid strength A1 signal, the olefin constituents signals, the reference acid strength A90 signal and the received voltages.

Claim 5

A system as described in claim 3 in which the rate signal means includes means connected to the flow rate sensing means, to the circuit and receiving direct current voltages corresponding to conversion constants H and J for providing the AR1 and the ALR signals in accordance with the sensed acid flow rate FRA, the sensed bottom products flow rate FRp, the alkylate concentration ALK signal, the received voltage and the following equations: AR1 (H)(FRA) and ALR (J)(FRBP)(ALK), acid consumption factor signal means connected to the acid strength sensing means and to the acid strength signal means and receiving the voltages corresponding to the constants Kf, Kg. Kh, Ki and Kj for providing acid consumption factor theta 1, theta 2 and theta 3 signals in accordance with the sensed acid strength A1 signal, the reference acid strength signal A90, the received voltages and the following equations: theta 1 Kf+ Kg(A1- A90)+Kh(A1- A90)2+ Ki(A1- A90)+Kj(A1-A90)4+ Kk(A1- A90)5 theta 2 Kf+ Kg(A2- A90)+Kh(A2- A90)2+ Ki(A2- A90)3+ Kj(A2-A90)4+ Kk(A2- A90)5 theta 3 Kf+ Kg(A3- A90)+Kh(A3- A90)2+ Ki(A3- A90)3+ Kj(A3-A90)4+ Kk(A3- A90)5 where theta 1, theta 2 and theta 3 are acid consumption factors associated with the sensed acid strength A1 and the predetermined acid strengths A2 and A3, respectively, and means connected to the AR1 signal means, to the theta 1, theta 2 and theta 3 signal means and to the p2- p3 signal means for providing the AR2 and AR3 signals to the p2- p3 signal means in accordance with the AR1, theta 1, theta 2 and theta 3 signals and the following equations: AR2 ( theta 2/ theta 1) AR1, and AR3 ( theta 3/ theta 1) AR1.

Claim 6

A system as described in claim 4 in which the phi 1, phi 2 and phi 3 signal means includes means connected to the olefin sensing means and receiving a direct current voltage corresponding to the term 100 for providing a ratio M signal in accordance with the olefin constituents signals, the received voltage and the following equation: M (Propylene/Olefins) X 100 where propylene and olefins refer to their concentrations in the reaction, and a plurality of networks, each netowrk connected to the ratio M signal means, to the acid strength signal means and receiving direct current voltages corresponding to reference ratios MU and ML and constants Ka through Kd, one of the networks being connected to the acid strength sensing means, uses the received voltages and signals to provide an octane factor phi 1, phi 2 or phi 3 signal associated with the acid strength A1, A2 or A3 signal in accordance with the following equation: phi L Ka(A-A90) + Kb(A-A90)2 + Kc(A-A90)5, where the term A without a subscript refers to the associated acid strength A1, A2 or A3, phi L corresponds to an octane adder factor phi 1, phi 2 or phi 3 when the ratio M signal is equal to or less than the reference ratio ML voltage, in accordance with the following equation: phi U + Kd(A-A90)3 where phi U corresponds to an octane adder factor phi 1, phi 2 or phi 3 when the ratio M signal is equal to or greater than the reference ratio MU voltage, and in accordance with the next two previous equations and the following equation: phi L U phi L(MU - M/MU - ML) + phi U(M - ML/MU - ML) where phi L U corresponds to an octane adder factor phi 1, phi 2 or phi 3 when the ratio M signal is greater than the reference ratio ML voltage but less than the reference ratio MU voltage.

Claim 7

A system as described in claim 5 in which the general profit P equation for the alkylation unit may be a second order equation as follows: p Q + RA + SA2, or a linear equation as follows: p Q + RA where Q, R and S are constants and A is an acid strength, and the control signal network includes means connected to the circuit, to the acid strength signal means and to the acid strength sensing means for providing signals corresponding to R and S in accordance with the acid strength A1, A2 and A3 signals, and means connected to the R and S signal means for determining whether the profit equation is a second order equation or a linear equation and providing a signal corresponding to an optimum acid strength AO when the profit equation is a second order equation and providing a signal corresponding to a predetermined change Delta in acid strength when the profit equation is a linear equation and the sensed acid strength A1 is not an optimum acid strength.

Claim 8

A system as described in claim 6 in which the control means further comprises means connected to the acid strength signal means, to the control means and to the network providing the control signal for permitting the control signal to be provided to the control means when the desired acid strength is equal to or greater than the reference acid strength A90 and not providing the control signal to the control means when the desired acid strength is less than the reference acid strength A90.

Claim 9

A system as described in claim 6 in which the R and S signal means provide the R and S signals in accordance with the following equations: R ( p2(A32- A12) + p3(A12- A22))/D, S ( p2(A1- A3) + p3(A2- A1))/D, and D A1(A22- A32) + A2(A32- A12) + A3(A12- A22).

Claim 10

A system as described in claim 6 in which the determining means includes means connected to the R and S signal means for providing the optimum acid strength Ao signal in accordance with the R and S signals and the following equation: Ao - R/2S, change signal means connected to the Ao signal means and to the acid strength sensing means for providing a change signal corresponding in magnitude to the difference between the Ao and A1 signals and in polarity to a relationship between the Ao and A1 signals, first switching means connected to the change signal means and receiving direct current voltages of opposite polarities, one received voltage corresponds to the predetermined change Delta in one direction while the other voltage corresponds to the predetermined change Delta in an opposite direction, for providing the one received voltage when the change signal from the change signal means is of one polarity and the other received voltage when the change signal is not of the one polarity, second switching means connected to the first switching means and to the change signal means for passing the change signal while blocking a predetermined change voltage from the first switching means when the change signal has a smaller, or equal, amplitude than a predetermined change voltage, and blocking the change signal from the change signal means while passing a predetermined change voltage from the first switching means when the change signal has a larger amplitude than a predetermined change voltage.

Claim 13

A method as described in claim 10 in which the providing of the control signal step includes the steps of providing signals corresponding to an acid strength A2 greater than the sensed acid strength A1, to an acid strength A3 less than the sensed acid strength A1 and to a reference acid strength A90; providing signals corresponding to anticipated changes p2 and p3 in profit associated with the acid strengths A2 and A3, respectively, in accordance with the acid strength A1, A2, A3 and A90 signals, the aCid flow rate signal, the bottom product flow rate signal, and the economic value signals; and providing a signal corresponding to a desired acid strength as the control signal in accordance with the acid strength A1, A2 and A3 signals and the profit change p2 and p3 signals.

Claim 14

A method as described in claim 11 in which the providing of the profit change signal steps includes the steps of providing signals corresponding to octane adder factors phi 1, phi 2 and phi 3 in accordance with the sensed acid strength A1 signal, the reference acid strength A90 signal, the olefin constituents signals; providing rate signals ALR, AR1, AR2 and AR3 corresponding to an alkylate rate, an acid rate associated with acid strength A1, an acid rate associated with acid strength A2 and an acid rate associated with acid strength A3, respectively, in accordance with the flow rate signals, the alkylate concentration signal and the acid strength A1, A2, A3 and A90 signals, and providing the p2 and p3 signals in accordance with the economic value signals, the octane adder factors phi 1, phi 2 and phi 3 signals, the ALR signal and the AR1, AR2 and AR3 signals in the following equations: p2 ( phi 2 - phi 1)(ALR)(VO) - (AR1- AR2)(VA) and p3 ( phi 3 - phi 1)(ALR)(VO) - (AR1-AR2)(VA).

Claim 15

A method as described in claim 12 in which the step of providing rate signals includes providing the AR1 rate signal and the ALR rate signal in accordance with the signal corresponding to the flow rate FRA of the acid and the signal corresponding to the flow rate FRBP of the sensed bottom product and the signal corresponding to the alkylate ALK concentration and the following equations: AR1 (H)(FRA) and ALR (J)(FRBP)(ALK) where H and J are conversion factors, providing acid consumption factor theta 1, theta 2 and theta 3 signals associated with the acid strength A1, A2 and A3 in accordance with the sensed acid strength A1 signal, the reference acid strength A90 signal and the acid strength signals A2 and A3 and the following equations: theta 1 Kf+Kg(A1-A90)+Kh(A1-A90)2+Ki(A1-A90)3+Kj(A1-A90)4 + Kk(A1-A90)5 theta 2 Kf+Kg(A2-A90)+Kh(A2-A90)2+Ki(A2-A90)3+Kj(A2-A90)4+Kk(A2-A90)5 theta 3 * Kf+Kg(A3-A90)+Kh(A3-A90)2+Ki(A3-A90)3+Kj(A3-A90)4 +Kk(A3-A90)5 where Kf, Kg, Kh, Ki, Kk and Kj are constants, and providing the AR2 and AR3 rate signals in accordance with the AR1 rate signals and the acid consumption factor theta 1, theta 2 and theta 3 signals and the following equations: AR2 ( theta 2/ theta 1) AR1, and AR3 ( theta 3/ theta 1) AR1

Claim 16

A mEthod as described in claim 12 in which the step of providing the phi 1, phi 2 and phi 3 signals include providing a ratio M signal in accordance with the olefin constituent signals and the following equation: M (Propylene/Olefins) X 100 where propylene and olefins refer to their concentrations, and in which each phi 1, phi 2 or phi 3 signal is provided in accordance with the associated acid strength A1, A2 or A3 signal and the reference acid strength signal A90 and the following equation: phi L Ka(A-A90) + Kb(A-A90)2+Kc(A-A90)5, where the term A without a subscript refers to the acid strength A1, A2 or A3 signal other than the reference acid strength when the ratio M signal is equal to or less than a reference ratio ML signal, in accordance with the following equation: phi U +Kd(A-A90)3 where the ratio M signal is equal to or greater than the reference ratio MU signal, and in accordance with the following equation: phi L U phi L(MU - M/MU - ML) + phi u (M - ML/MU -ML) where phi L u corresponds to an octane adder factor phi 1, phi 2 or phi 3 when the ratio M signal is greater than the reference ratio ML voltage but less than the reference ratio MU voltage.