JPH07108372B2 - Catalytic reactor simulator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a simulator for the purpose of operator training of a controller of a process having a catalytic reaction type reactor, the activity of which easily changes depending on operating variables,
The present invention relates to improvement of means for realizing a simulator for a catalyst part, which has a large effect on reaction products.

(Prior Art) Based on FIG. 15, an outline of a reformer (reforming) plant for obtaining gasoline with a high octane number from raw material naphtha will be described.

1 is an input line for refined raw material naphtha, 2 is circulating hydrogen H ₂
The naphtha and the circulating hydrogen are mixed, heated in the heating furnace 4 through the pipe 3, and introduced into the reactor 5.

In the reactor, naphtha having a low octane number is catalytically reacted with a platinum-alumina-based catalyst at high temperature and high pressure to change the structure of hydrocarbons in the naphtha and convert it into a reformed oil having a high octane number.

The reaction product from the reactor is cooled and the separator 6
Is led to and the gas mainly consisting of hydrogen is separated. A part of this gas is pressurized by the compressor 7 and is supplied to the pipeline 2
Is supplied as circulating hydrogen.

The liquid product from the separator is guided to a stabilizer 8 to remove light hydrocarbons and is stabilized into a reformed gasoline having predetermined physical property specifications to be a product GS.

9 is a drum, and the distillate product on the top of the stabilizer is
It is guided to the drum 9 and separated into off-gas and LPG, a part of the LPG is returned to the stabilizer, and the other is a product.

In such a process, three main parameters to be controlled are the octane number RON of the product GS, the purity of hydrogen H ₂ , and the yield of the GS product (Yield).

The main operating conditions are reactor input temperature T, reactor pressure P, liquid space velocity LHSV (Liquid Hourly Spac).
e Velocity), and the molar ratio of hydrogen / oil is H ₂ / HC, and the life and activity of the reactor are greatly affected by these operating conditions, which are important parameters for economical operation.

The liquid space velocity LHSV is calculated by converting from the measured flow rate F _FD of naphtha and the catalyst amount, and the hydrogen / oil molar ratio H ₂ / HC is the measured flow rate F _FD of naphtha, the measured density SG, molecular weight MW, hydrogen. The flow rate measurement value FRG and the hydrogen purity measurement value H _{2 are} obtained.

The activity of the catalyst in the reactor declines due to long-term factors such as a decrease in activity due to carbon deposition with the passage of operating time and short-term factors due to the severity due to different operating conditions, and the life of the catalyst within a certain period of time decreases. run out.

As described above, since the activity of the catalyst decreases with time, it is necessary to operate while gradually increasing the inlet temperature of the reactor to maintain the target octane number.

If the reactor pressure is lowered, hydrogen purity and yield increase, but carbon deposition on the catalyst increases and it becomes a factor that shortens the life. Therefore, it is necessary to operate the reactor at a certain suitable value.

If H ₂ / HC is operated at a small ratio, it will save fuel in the heating furnace and reduce the load on the compressor, but it will increase the adhesion of carbon to the catalyst and also reduce the life, so Operations that maintain a certain aptitude ratio are required.

LHSV is determined by the throughput of raw naphtha, which is determined by the target reaction temperature, pressure, octane number, etc. at the time of design. If this value is too small, carbon deposition on the catalyst will increase. However, it is a factor that shortens the service life, so it is necessary to operate with an appropriate value maintained even during startup.

(Problems to be solved by the invention) As described above, the operating conditions affect the life and activity of the catalyst. Therefore, in order to realize economical operation, an operator using a reactor model simulating the catalyst activity depending on operating variables is used. Training is required.

Fig. 16 is a conceptual diagram of a conventional reactor model, in which the catalyst life and activity are considered in the same dimension, and a reaction rate equation considering diffusion and adsorption is modeled, and the composition of the reaction product is based on this. And the characteristics were simulated.

However, in the calculation of only the reaction rate (that is, the activity of the catalyst), it is not possible to consider a long-term phenomenon (change of activity for one year with time) within a limited time of 1 to 2 hours like a training simulator. , High-precision training with the same feeling as the actual plant cannot be expected.

An object of the present invention is to provide a simulator that can solve such problems.

(Means for Solving the Problems) A structural feature of the present invention is that in a simulator of a catalytic reaction type reactor, ideal decay data of life decay corresponding to training time corresponding to training time and ideal decay data and operating variables are used. It is provided with a catalyst life simulator function calculated by the life decrease factor and a catalyst activity simulator function calculated by the function based on the catalyst life and the operating variable calculated by this function.

(Operation) The catalyst life simulator function calculates the ideal decay data of the life decay corresponding to the elapsed time of the catalyst corresponding to the training time and the life reduction factor by the operating variable.

The catalyst activity simulator function calculates the catalyst activity based on the catalyst life and the operating variables calculated by the catalyst life simulator function.

(Example) FIG. 2 is a basic configuration diagram of the simulator of the present invention.
The reactor model M includes a catalyst life simulator M ₁ and a catalyst activity simulator M ₂ .

The signal processing procedure will be described with reference to the flowchart of FIG. The catalyst life simulator M ₁ is supplied with the ideal life data L _f0 of the catalyst corresponding to the training time in a predetermined period from the program generator, and the life of the actual plant at that time is calculated according to the plant operation variable data.
Calculate L _f .

The catalyst activity simulator M ₂ calculates and outputs the catalyst activity ACT ₀ from the catalyst life L _f at that time and the plant operating variables.

Each characteristic value of the reaction product is calculated based on the activity output ACT ₀ .

An embodiment in which the simulator of the present invention is applied as a simulator of the process shown in FIG. 15 will be described based on FIG. The same elements and operating variables as those described in FIG. 15 will be described with the same reference numerals.

Reference numerals 10, 11 and 12 are input terminals to which the naphtha feed flow rate measurement value F _FD , the closed measurement value SG, and the temperature measurement value T as operating variables are supplied as simulation signals.

13 is a calibrator that calculates the liquid hourly space velocity LHSV by multiplying the conversion value determined by the amount of catalyst from the measured feed flow rate F _FD of naphtha, and 14 is an indicator of LHSV.

Reference numeral 15 is a manual operator that generates an input MV to the model 16 of the compressor 7, and obtains a simulated signal of the flow rate measurement value F _RG of circulating hydrogen from the output of the model 16. 17 is an indicator of _FRG .

This flow rate measurement value F _RG is guided to the function calculator 19, and the pressure difference ΔP between the input and output of the compressor is calculated in a functional relationship as shown in FIG. This calculated output is added by the separator outlet hydrogen pressure P ₀ given from the manual setting device 20 and the adder 21,
A simulated signal of the measured circulating hydrogen pressure P is obtained. Reference numeral 22 is an indicator of the measured value P.

23 is a calculator for calculating the hydrogen / oil molar ratio H ₂ / HC, and inputs the feed flow rate measurement value F _FD and the density measurement value SG of the naphtha, the flow rate measurement value F _RG of the circulating hydrogen, and the purity signal H _{2 of the} hydrogen. Then, the calculation of H ₂ / HC = (F _RG · H ₂ % · 1/100) / (F _FD · SG · 1000 / MV) (1) is executed. This ratio ranges from 0 to 10. 24 is an indicator of this calculation output H ₂ / HC.

Next, the part of the catalyst life insulator function M ₁ and the catalyst activity simulator function M ₂ which form the main part of the present invention will be described.

_Reference numeral 25 is an arithmetic unit that forms M ₁ , and the program generator 26 supplies ideal life data L _f0 as shown in FIG. In this example, the training time is set to 2 hours, and the reduction of the catalyst life for one year is from 1 (100%) to 0.5 (50
%) Given as a curve that gradually decreases.

Further, in this calculator 25, the signals ΔT, L _f2 , L _f3 , and L _f4 for calculating the factor of reduction from the ideal life are respectively calculated by the function calculators 27, 28, 2
Sourced from 9,30.

The function calculator 27 has a function of calculating the difference ΔT between the proper temperature corresponding to the life of the catalyst and the actual operating temperature. As shown in Fig. 5, the ideal operating temperature for 100% catalyst life is 525 ℃, 50
The ideal operating temperature of% is assumed to be 2 ° C higher than the ideal operating line of 533 ° C, and it is assumed that the life decreases when operating in the region R above this line. When the operating temperature at the operating point X at the life L _x point is T _RX and the temperature of the ideal straight line at this time is T _Lf , the calculator 25 calculates L _f = L _f0 − {T _RX − (T _Lf +2 )} · Α (2), the actual life L _f reduced by the operating variables is calculated from the ideal life L _f0 .

The function calculator 28 inputs the measured value of the pressure P and calculates the life reduction factor L _{f2 based} on the characteristics shown in FIG. That is,
The value L _f2 that shortens the service life when operating at a pressure of 22 ^K or less is specified. The calculator 25 inputs this signal and operates from the ideal service life Lf0 by L _f = L _f0 −L _f2 (3) The actual life L _f reduced by the variable is calculated and calculated.

The function calculator 29 inputs the measured value of the hydrogen / oil molar ratio H ₂ / HC and calculates the life reduction factor L _{f3 based} on the characteristics shown in FIG. 7. That, and defines a value L _f3 life is reduced when operating at a ratio of 6 or less, the arithmetic unit 25, and inputs the _{signal, L f = L f0 -L f3} (4) by the ideal life L _f0 From this, the actual life L _f reduced by the operating variables is calculated and calculated.

The function calculator 30 inputs the measured value of the liquid space velocity LHSV and
The life reduction factor L _f4 is calculated from the characteristics shown in the figure. That is, the value L that shortens the life when operating below 0.75
_f4 is specified, and this signal is input to the calculator 25 and calculated by calculating the actual life L _f reduced by the operating variables from the ideal life L _f0 by L _f = L _f0 −L _f4 (5) To do.

31 is the actual life calculated by the calculator 25 in this way
It is an indicator of L _f .

Next, the operation of the computing unit 32 which forms part of the catalytic activity simulator function will be described. This calculator is a functional calculator 33,3
Inputs the operation output ACT ₁ , ACT ₂ , ACT ₃ from 4,35 and outputs ACT ₀ .

The function calculator 33 calculates the relationship shown in FIG. 10 showing the decrease in activity due to the life L _{f and} outputs it as ACT ₁ .
It is a characteristic that decreases to 0.5 at 100% and 0.4 at 50%.

Function calculator 34, which calculates the relationship shown in FIG. 11 which represents an increase of activity by a reduction in the pressure P is output as ACT _2, lowering the pressure as 0.5 0.45,25 ^k at 50 ^k And the activity becomes higher.

The function calculator 35 calculates the aromatic fraction in the feed on behalf of the density SG which is a physical property of the feed naphtha.
The relationship shown in FIG. 12 is calculated and output as ACT ₃ . That is, 0.48 to 0.53 for SG change from 0.71 to 0.76
It is a characteristic that changes up to.

The arithmetic unit 32 simply adds these three inputs and outputs ACT ₀ = ACT ₁ + ACT ₂ + ACT ₃ −β (6).

Function calculator forming another part of the catalytic activity simulator
Both 36 and 37 input the temperature measurement value T, and calculate the effect of the reaction temperature on the activity.

The function calculator 36 inputs the input temperature T of the reactor and
The relationship shown in Fig. 13 is calculated and output as ACT ₄ , which is a characteristic that changes from 0.5 to 0.6 with respect to changes in 525 ° C to 550 ° C.

The function calculator 37 inputs the input temperature T of the reactor and
The relationship shown in Fig. 14 is calculated and output as ACT ₅ , which is a characteristic that changes from 0.5 to 0.65 with respect to changes from 525 ° C to 550 ° C.

Based on the signals ACT ₀ , ACT ₄ , and ACT ₅ representing the activity, the operation units 38, 39,
40 calculates the octane number RON, the hydrogen purity H2, and the yield (yield) change amount ΔY as follows.

_{RON = 120 {0.79+ (ACT 0} -0.5 + ACT 5)} (7) H 2 = 100 {0.73+ (ACT 0 -0.5 + ACT 4)} (8) ΔY = 3.3 (ACT 0 -0.5 + ACT 5) (9 ) 41 is a process model having a first-order lag and a dead time, which is inserted to approximate the change in the octane number signal RON to the response of the actual plant.

42 is a process model having a first-order lag, which is inserted to approximate the change in the hydrogen purity signal H ₂ to the response of the actual plant.

43, 44, and 45 are indicators of octane number RON, hydrogen purity H ₂ , and number rate change Y, respectively.

In the process simulator configured as described above, the model of the reactor targeted by the present invention is within the range of the block M indicated by the dotted line.

In this example, the reactor of the reformer process of petroleum refining was targeted, but it can be easily applied to the continuous fixed catalyst reactor in other processes such as hydrorefining (desulfurization) process and catalytic cracking process. Is.

(Effects of the Invention) As described above, according to the present invention, (1) since the state of the catalyst that governs the reaction conditions is divided into two factors (lifetime and activity), the reaction rate (generally called catalyst activity) Can be accurately simulated with time.

(2) Since the influence of each plant operation variable on the catalyst is divided into a long-term factor and a short-term factor, the trainee can be given the sensation of operating an actual plant.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a basic configuration diagram of the present invention, FIG. 3 is a flow chart diagram showing a signal processing procedure, and FIG. 4 is a program transmitter for giving ideal life data. 5 to 14 are characteristic diagrams of the function calculators 19, 27, and
28, 29, 30, 33, 34, 35, 36, 37 characteristic diagram, FIG. 15 is a configuration diagram of a reformer plant, and FIG. 16 is a configuration diagram showing an example of a conventional technique. 10,11,12 …… Operating variable input terminal, 13 …… Calculator, 14,17,22,24,31,43,44,45 …… Indicator, 15,20 …… Manual setter, 16,41, 42 ... Process model, 19,27,28,29,
30,33,34,35,36,37 …… Function calculator, 23,25,32,38,39,40
…… Calculator, 26 …… Program generator

Claims (1)

[Claims] 1. A simulator for a catalytic reaction type reactor, which comprises a catalyst life simulator function for calculating the life decay ideal decay data corresponding to the elapsed time of the catalyst corresponding to the training time and a life shortening factor by an operating variable, A simulator for a catalytic reaction reactor comprising a catalyst activity simulator function for calculating catalyst activity based on the catalyst life and operating variables calculated by this function.