Abstract: A control system controls the temperature of gas oil being charged to a reactor in a hydrotreating unit. The control system includes a heater which heats the gas oil in accordance with a control signal corresponding to a desired temperature. A gravity analyzer senses the API gravity of the gas oil and provides a corresponding signal. A sulfur analyzer senses the sulfur content of the gas oil and provides a representative signal. A boiling point analyzer senses the 50% boiling point temperature, the initial boiling point temperature and the end point temperature of the gas oil and provides corresponding signals. A flow rate sensor provides a signal corresponding to the flow rate of the gas oil entering the heater. A control signal circuit provides the control signal to the heater in accordance with the signals from the gravity analyzer, the sulfur analyzer, the boiling point analyzer and the flow rate sensor.

Abstract: A control system controls the temperature of naphtha being charged to a reactor in a hydrotreating unit. The control system includes a heater which heats the naphtha in accordance with a control signal corresponding to a desired temperature. A gravity analyzer senses the API gravity of the naphtha and provides a corresponding signal. A sulfur analyzer senses the sulfur content of the naphtha and provides a representative signal. A boiling point analyzer senses the 50% boiling point temperature, the initial boiling point temperature and the end point temperature of the naphtha and provides corresponding signals. A flow rate sensor provides a signal corresponding to the flow rate of the naphtha entering the heater. A control signal circuit provides the control signal to the heater in accordance with the signals from the gravity analyzer, the sulfur analyzer, the boiling point analyzer and the flow rate sensor.

Abstract: A control system controls the temperature of kerosine/diesel fuel being charged to a reactor in a hydro-treating unit. The control system includes a heater which heats the kerosine/diesel fuel in accordance with a control signal corresponding to a desired temperature. A gravity analyzer senses the API gravity of the kerosine/diesel fuel and provides a corresponding signal. A sulfur analyzer senses the sulfur content of the kerosine/diesel and provides a representative signal. A boiling point analyzer senses the 50% boiling point temperature, the initial boiling point temperature and the end point temperature of the kerosine/diesel fuel and provides corresponding signals. A flow rate sensor provides a signal corresponding to the flow rate of the kerosine/diesel fuel entering the heater. A control signal circuit provides the control signal to the heater in accordance with the signals from the gravity analyzer, the sulfur analyzer, the boiling point analyzer and the flow rate sensor.

Abstract: A desulfurization catalyst is activated by being heated to a temperature between about 750.degree. and 850.degree. F. in the presence of the charge stock to be desulfurized during the initial stages of the on-stream period. In a preferred embodiment the catalyst, prior to the heat treatment, is sulfided at a low temperature and low pressure. The resulting catalyst effectively desulfurizes a petroleum hydrocarbon charge stock with reduced hydrogen consumption.

Abstract: A desulfurization catalyst is activated by being heated to a temperature between about 750.degree. and 850.degree.F. in the presence of the charge stock to be desulfurized during the initial stages of the on-stream period. In a preferred embodiment the catalyst, prior to the heat treatment, is sulfided at a low temperature and low pressure. The resulting catalyst effectively desulfurizes a petroleum hydrocarbon charge stock with reduced hydrogen consumption.