Temperature control system for hydrocarbon conversion process

Claim 2

Control system of claim 1 wherein there is provided eighth means for withdrawing unconverted liquid from said conversion process, and said eighth means is operatively responsive to said fourth signal when said sixth signal is a function of said fifth signal.

Claim 3

Control system of claim 1 wherein said process comprises a hydrocarbon conversion process and said fluid mixture comprises hydrocarbon to be converted.

Claim 4

In a fluid mixture conversion process, wherein a fluid mixture, comprising gaseous reactant and a fluid to be converted, is introduced into a conversion zone maintained under conversion conditions; gaseous reactant is introduced into said process; conversion zone effluent containing normally liquid and normally gaseous components is passed into a separation zone; normally gaseous components are removed from the separation zone; normally liquid components are removed from the separation zone and passed into a fractionation column; conversion products are removed from the upper portion of the fractionation column; a level of unconverted liquid is maintained in the lower portion of the column; and said unconverted liquid is returned to the conversion zone; a control system for maintaining the level of conversion of the fluid mixture at a level responsive to the availability of said gaseous reactant, which comprises: a. first means to establish a first signal functionally representative of the temperature of the fluid mixture, said first signal operatively connected to control means for heat input to said fluid mixture; b. second means to establish a second signal representing the temperature differential of fluid into and out of said conversion zone, said second signal operatively connected to said first means to reset said first signal in a manner sufficient to maintain said differential temperature at a hereinafter specified value; c. third means comprising proportional-derivative control means for establishing a third signal representative of the rate of flow of said gaseous reactant into said process; d. fourth means for establishing a fourth signal representative of said liquid level in the lower portion of the fractionating column; e. fifth means for establishing a fifth signal representative of the pressure within said conversion zone; f. sixth means receiving said fourth and fifth signals and developing a sixth signal which is a function of said fifth signal when said pressure is below a predetermined level and which is a function of said fourth signal when said pressure is at least at said predetermined level; and, g. seventh means for summing said third and sixth signals thereby producing a seventh signal representative of the desired value of said differential temperature, said seventh signal operatively connected to said second means to reset the second signal.

Claim 5

Control system of claim 5 wherein said fifth means is representative of the pressure of said gaseous reactant passing into said hydrocarbon conversion process.

Claim 6

Control system of claim 5 wherein there is provided eighth means for withdrawing unconverted liquid from said conversion process, and said eighth means is operatively responsive to said fourth signal when said sixth signal is a function of said fifth signal.

Claim 7

Control system of claim 5 wherein said process comprises a hydrocarbon conversion process and said fluid mixture comprises hydrocarbon to be converted.

Claim 8

In a hydrocarbon conversion process wherein a hydrocarbon to be converted is admixed with a gaseous reactant and a hereinafter specified recycle hydrocarbon to produce a conversion zone feed mixture; said feed mixture is passed at conversion temperature through a first conduit into a conversion zone comprising a plurality of fixed catalyst beds in series; the effluent from each catalyst bed preceding the last bed is contacted with additional gaseous reactant being introduced through a second conduit associated with each bed succeeding the first catalyst bed; the conversion zone effluent is removed from the last catalyst bed and separated in a separation zone to provide at least a normally liquid hydrocarbon fraction and a normally gaseous product fraction; the normally gaseous product fraction is withdrawn from the separation zone via a third conduit; the normally liquid hydrocarbon fraction is withdrawn from the separation zone and passed into a fractionation column; converted hydrocarbon products are removed from the upper portion of the fractionation column; a level of unconverted hydrocarbon is maintained in the lower portion of the column; the unconverted hydrocarbon is returned to the conversion zone as said recycle hydrocarbon specified; and, makeup gaseous reactant is passed into the process via a fourth conduit; a control system for maintaining the level of hydrocarbon conversion at a level responsive to the availability of said gaseous reactant, which comprises: a. first means to establish a first signal functionally representative of the temperature of the feed mixture, said first signal operatively connected to control means for heat input to said feed mixture; b. second means to establish a second signal representing the temperature differential of fluid passing into and out of the first bed of said plurality of catalyst beds, said second signal operatively connected to said first means to reset said first signal in a manner sufficient to maintain the temperature differential across said first bed at a hereinafter specified value; c. third means associated with each catalyst bed succeeding said first bed, to establish a third signal representing the temperature differential of fluids passing into and out of the associated succeeding catalyst bed in said plurality of beds, each third signal being operatively connected to fourth means hereinafter specified; d. fourth means associated with each succeeding catalyst bed, controlling the rate of flow of additional gaseous reactant in the correspondingly associated second conduit, said fourth means being operatively responsive to the associated third signal in a manner sufficient to adjust said rate of flow to maintain the temperature differential across the associated succeeding catalyst bed at a hereinafter specified value; e. fifth means comprising proportional-derivative control means to establish a fifth signal representative of the rate of flow of said makeup gaseous reactant; f. sixth means for establishing a sixth signal representing said liquid level in the lower portion of the fractionating column; g. seventh means for establishing a seventh signal representative of the pressure within said conversion zone; h. eighth means receiving said sixth and seventh signals and developing an eighth signal which is a function of said seventh signal when said pressure is below a predetermined level and which is a function of said sixth signal when said pressure is at least at said predetermined level; i. ninth means for summing said fifth and eighth signals, thereby producing a ninth signal representative of the desired specified value of each differential temperature; and, j. tenth means transmitting said ninth signal to said second means to reset said second signal, and to said third means to reset each third signal.

Claim 9

Control system of claim 9 wherein said seventh means is representative of the pressure of said makeup gas passing into said process.

Claim 10

Control sysTem of claim 9 wherein there is provided eleventh means for withdrawing unconverted hydrocarbon from said hydrocarbon conversion process, and said eleventh means is operatively responsive to said sixth signal when said eighth signal is a function of said seventh signal.

Claim 11

In a hydrocarbon conversion process wherein a hydrocarbon to be converted is admixed with a gaseous reactant and a hereinafter specified recycle hydrocarbon to produce a conversion zone feed mixture; said feed mixture is passed at conversion temperature through a first conduit into a conversion zone comprising a plurality of fixed catalyst beds in series; the effluent from each catalyst bed preceding the last bed is contacted with additional gaseous reactant being introduced through a second conduit associated with each bed succeeding the first catalyst bed; the conversion zone effluent is removed from the last catalyst bed and separated in a separation zone to provide at least a normally liquid hydrocarbon fraction and a normally gaseous product fraction; the normally gaseous product fraction is withdrawn from the separation zone via a third conduit; the normally liquid hydrocarbon fraction is withdrawn from the separation zone and passed into a fractionation column; converted hydrocarbon products are removed from the upper portion of the fractionation column; a level of unconverted hydrocarbon is maintained in the lower portion of the column; the unconverted hydrocarbon is returned to the conversion zone as said recycle hydrocarbon specified; and, makeup gaseous reactant is passed into the process via a fourth conduit; a control system for maintaining the level of hydrocarbon conversion at a level responsive to the availability of said gaseous reactant, which comprises: a. first means to establish a first signal functionally representative of the temperature of the feed mixture, said first signal operatively connected to control means for heat input to said feed mixture; b. second means to establish a second signal representing the temperature differential of fluid passing into and out of the first bed of said plurality of catalyst beds, said second signal operatively connected to said first means to reset said first signal in a manner sufficient to maintain the temperature differential across said first bed at a hereinafter specified value; c. third means associated with each catalyst bed succeeding said first bed, to establish a third signal representing the temperature differential of fluids passing into and out of the associated succeeding catalyst bed in said plurality of beds, each third signal being operatively connected to fourth means hereinafter specified; d. fourth means associated with each succeeding catalyst bed, controlling the rate of flow of additional gaseous reactant in the correspondingly associated second conduit, said fourth means being operatively responsive to the associated third signal in a manner sufficient to adjust said rate of flow to maintain the temperature differential across the associated succeeding catalyst bed at a hereinafter specified value; e. fifth means comprising proportional-derivative control means to establish a fifth signal representative of the rate of flow of said normally gaseous product fraction; f. sixth means for establishing a sixth signal representing said liquid level in the lower portion of the fractionating column; g. seventh means for establishing a seventh signal representative of the pressure within said conversion zone; h. eight means receiving said sixth and seventh signals and developing an eighth signal which is a function of said seventh signal when said pressure is below a predetermined level and which is a function of said sixth signal when said pressure is at least at said predetermined level; i. ninth means for summing said fifth and eighth signals, thereby producing a ninth signal representative of the desired specified value of each differential temperature; and, j. tenth means trAnsmitting said ninth signal to said second means to reset said second signal, and to said third means to reset each third signal.

Claim 12

Control system of claim 12 wherein said seventh means is representative of the pressure of said makeup gas passing into said process.

Claim 13

Control system of claim 12 wherein there is provided eleventh means for withdrawing unconverted hydrocarbon from said hydrocarbon conversion process, and said eleventh means is operatively responsive to said sixth signal when said eighth signal is a function of said seventh signal.