SU295317A1 - Method of automatic control of furnace-reactor unit of hydrocracking plant - Google Patents

Description

The invention relates to the automation of production processes, in particular, to furnace-reactor units of a hydrocracking unit, and can be used in the chemical and petrochemical industries. There is a known method of automatically controlling a furnace-reactor unit of a hydrocracking unit by maintaining the temperature of the gas-raw mixture, for example, between 420 and 430 ° C at the exit of the furnace by varying the fuel consumption to the furnace and controlling the inlet temperature to each catalyst layer by affecting the flow rate of the cooling gas supplied to the same layer. However, the known method does not have sufficient quality of regulation and the rection may go into the zone of thermal explosion. In order to eliminate these drawbacks in the proposed method, the temperature at the inlet to the catalyst bed is adjusted by the temperature at the outlet of the layer when the last permissible value is exceeded, for example, within 445 - and, moreover, the temperature is lowered, for example, within 390-410 ° C depending on the total flow rate of the cooling gas supplied to the reactor, the essence of the method is explained by a circuit consisting of temperature sensors 1-7, flow sensors 8-10, proportionally - integral regulators 11-14, secondary self-recording at oors 15-18 and 19-21, devices 22-25 of the simplest algebraic devices 26-29 of signal limiting, setting device (USEPP element) 30, three-membrane pneumorel (USEPP element 31, relay 32 of thermocouple switching 33-39, chromel-Kopelevy diaphragms 40-42, nHeBMaTH4e CJfHX devices 43-44, valves 45-48, relays 49-51 ratios. Each layer of catalyst has two thermocouples, one inlet and one outlet of the layer; the top one (34,36,38) to maintain a stable level of reaction temperature, the bottom one (33,3.5 37) to control the heating of the catalyst bed (there may be catalyst damage or exothermic reaction to a thermal explosion zone). Thermocouple 37 is located in the catalyst zone of Zone A. The Viv catalyst zones of the catalyst have the same temperature control circuit. Sign in

the layer is measured by thermocouples 34 36. and through sensors 2 and 4 of the temperature in the well, the variable enters the controllers 13 and 14. The temperature of the entrance to the layer is corrected according to the temperature of exit; signals from thermocouples 33 and 35 through temperature sensors 1 and 3, limited to the minimum by instruments 26 and 27. devices 22 and 23 step up on summing up through relays 49 and 50 of correlation, to which the reference devices of secondary devices 15 and 16 are fed. Output pulses summing devices 22 and 23 are assigned to regulators 13 and 14, which control the supply of refrigerant to the reactor when valves 45 and 4b are used. Minimum limit signals are provided so that correction starts at a temperature above the critical value, for example 445 - 455 ° С, Dl In order to eliminate a push when a corrective element is connected to the circuit, relays 49 and 50 are provided for ratios. The circuit works as long as the total amount of refrigerant measured by diaphragms 40 and 41 and flow sensors 9 and 10 and added to the device 24 does not exceed the pre-set maximum; about the value When this moment comes, the pulse of the device 28 limits the signals, n. Arranged to maximum, will switch the channels in the relay 32 to switch, by disconnecting the task to controller 11 from the secondary device of the sensor and connecting to it the task from device 25 summing. The output pressure from the signal limiting device 28 is adjusted so that it corresponds to setting the desired temperature to the controller. This temperature must be obviously lower than the initial reaction temperature, e.g., 390-410 ° C. A precut unit 43 installed at the outlet of the limiting device serves to suppress the inertia of the object,

 the invention

1, Method for automatic control of a hydrocracking furnace-reactor unit by maintaining the temperature of the gas raw material, for example

within 420-430 ° C, at the exit of the furnace by varying the fuel consumption in the furnace and controlling the inlet temperature to each KaTajgHsasOpa layer by affecting the flow rate of the cooling gas supplied to the same layer, characterized in that, in order to improve the quality of regulation, the temperature at the entrance to the catalyst bed, the temperature at the exit from the bed is adjusted when the last permissible value is exceeded, for example, within 445 - 455 ° C.

2. Method POP.1, characterized in that, in order to prevent the reaction from entering the thermal explosion zone, the temperature is reduced, for example, between 390-410 ° C, at the exit of the furnace, depending on the total flow rate of cooling gas supplied in the reactor ..