EP3645670A1

EP3645670A1 - Operating systems for catalytic reforming

Info

Publication number: EP3645670A1
Application number: EP18732131.0A
Authority: EP
Inventors: Dzmitry STASENKA; Torsten RUBEL
Original assignee: Swiss Rr Engineering Group AG
Current assignee: Swiss Rr Engineering Group AG
Priority date: 2017-06-28
Filing date: 2018-06-26
Publication date: 2020-05-06
Also published as: CN110914385A; JP2020525627A; WO2019002320A1; US20200181508A1; EP3421574A1; US11248178B2; EA202090045A1

Abstract

The invention relates to a method for optimising the operation of a system for catalytic reforming. The system has a plurality of reactors containing a catalyst, through which working gas flows successively, wherein the composition of the working gas in the reactors changes and wherein a product results on the output side of the last reactor. According to the method, firstly specific constant properties and initial operating parameters of the system that are present during the operation are captured. A computational simulation of chemical processes in the reactors then takes place, wherein, in addition to the constant properties and the captured system operating parameters, results of a measurement of the chemical composition of the product resulting on the output side of the last reactor are incorporated. Then, a computational simulation of the chemical processes in the reactors is performed with different, varied operating parameters, wherein as varied operating parameters, in addition to a flow rate of molecular hydrogen, various temperatures of the working gas at the input of each reactor are also adjusted individually. A set of optimised operating parameters is determined from the calculated chemical composition.

Description

OPERATION OF PLANTS FOR THE CATALYTIC

REFORMING

The invention relates to the field of petroleum processing. Specifically, it relates to one part of petroleum refining, namely catalytic reforming to increase the octane number and recover molecular hydrogen and short chain hydrocarbons (commonly referred to as "LPG") from crude petroleum derived from crude oil distillation, and US Pat as needed also to increase the proportion of aromatics.

For the catalytic reforming, one knows in particular the traditional fixed bed reactors as well as the somewhat more expensive regenerative so-called CCR reactors. In general, reactors of both types have a rotationally cylindrical volume in which the catalyst - having a sandy consistency - is disposed between an outer gas-permeable wall and an inner gas-permeable wall and, generally from the outside to the inside, through a gas mixture with the vaporized, to be reformed Crude gasoline (naphtha) and a molecular hydrogen-containing cycle gas is flowed through. This gas mixture changes its composition through the process. Subsequently, this gas flowing through the reactor or reactors gas mixture is called working gas. In general, the working gas will successively pass through several reactor stages before it is separated as a reforming product in a post-processing step and the products resulting after separation (hydrogen gas mixture from which the recycle gas is diverted, reformate, LPG, steam, exhaust gas, etc.). ) can be obtained or further processed. In a so-called semi-regenerative plant, the reactor stages are formed by separate fixed-bed reactors, while in a regenerative (CCR) plant, the reactor stages are formed by sub-reactors, which may be arranged one above the other and flowed through by the catalyst.

The performance of the reactors depends on a number of parameters, including the working pressure generated by compressors, the operating temperature (generally plus minus 500 ° C), the composition and condition of the catalyst, and the composition of the working gas.

It is known to use a control software in catalytic reforming plants. Such regulates the working pressure and the working temperature on the basis of the heating elements required for the process as well as pumps of the plant on the basis of results of a gas chromatography of the resulting after the last reactor stage reforming product. Such a control software has the advantage that a rapid response to changing conditions in the plant would be possible (which is often not so relevant in practice, at least after a start-up process). However, such a control software is only limitedly suitable for the optimization of the process, not least because the requirement for reactions in real time only allows the capture and processing of very rough data.

Also known are kinetic reactor models, which in a genetic way, ie based on generic information about the components used under - J -

Use of statistical values that allow very rough modeling of assets.

Due to the very high throughputs and the very high operating costs of refming systems, optimization gains of a few percent or even in the per thousand range are also worth a considerable effort. It would therefore be desirable to have approaches on how to further improve the efficiency of existing or newly planned catalytic reforming plants. Such efficiency improvement is therefore the object of the present invention.

The present invention is based, inter alia, on the finding that a mathematical determination of operating parameters for operation in an equilibrium state (with constant operating parameters) of a plant for catalytic reforming is advantageous, in particular if as such ultimately adjustable operating parameters include the temperatures of the working gas can be set individually at the entrance of each reactor.

Accordingly, there is provided a method of operating a catalytic reforming plant comprising a plurality of catalyst-containing reactors through which a working gas containing hydrocarbons and molecular hydrogen successively flow, wherein the composition of the working gas in the reactors changes , and the output side of the last of the reactors results in a product. According to the method, in a first step, specific constant, fixed properties and operating parameters of the plant already in operation are recorded, and a chemical composition of the product or a subset of the product (for example, without the molecular hydrogen) is determined by measurement.

In a second step (first simulation phase), a simulation of the chemical processes in the reactors is carried out, taking into account different conditions in the different reactors, and in addition to the geometric properties and the operating parameters and the measured chemical composition is included in the simulation.

In a third step (second simulation phase), without the need for further measurements, a simulation of the chemical processes with varied operating parameters is undertaken. The invention according to one aspect is characterized in that, besides the flow rate of circulating gas (or of molecular hydrogen as constituent of the circulating gas), the temperatures of the working gas at the inlet of each reactor are set individually as operating parameters and manipulated variables.

The simulation according to the third step is used for the optimization of the operating parameters by determining, by varying the operating parameters, a set of operating parameters (including the individual working gas temperatures at the inlet of each reactor) optimized with respect to a given objective. The optimization of the operating parameters in the third step can be done in a conventional manner. One possibility is that initially a target variable is specified. Such may be a simple size, for example, the octane number, the total amount of reformate, the amount of hydrogen gas or the like. However, it can also be more complex and consist, for example, of a value which results from an objective function A of the parameters of the output-side product-in a simple example, this can be a weighted average of standardized parameters (octane number, amount of hydrogen gas, proportion of naphthenes, proportion of paraffins, etc.). This target value is then maximized by varying the operating parameters, for example first stepwise in a coarse grid and then in the vicinity of a maximum value or in a finer grid, etc. Also other known from numerical maximization methods such as the choice of random numbers as start values are conceivable.

Examples of objective functions are:

Maximizing the output of reformate at a given octane number: A (Ti, G, Q, P) -> max;

Maximizing the octane number with unchanged amount of reformate: Ok (Tj G, Q, P) -> max;

Maximizing the output of hydrogen (H2), given a limit on the octane number or the output of reformate

H2 (Ti, G, Q, P) ->max; Maximizing the output of one or more hydrocarbons (aromatics) in the reformate, limiting the other production parameters.

Ya, YH, Yn (Ti, G, Q, P) - * max;

The bandwidths in which the operating parameters are varied result from technologically reasonable limits that are known and documented for reactors:

Tmin <Ti <Tmax (T _m, Ti, Tma - variable temperature ranges for each reactor in his documented limits). The lower limit is determined, for example, by the reaction temperature of the catalyst, the upper limit by its heat resistance. For example, Tmin = 457 ° C, Tmax = 520 ° C (Pmin, Pi ₅ Pmax, - variable pressure ranges per reactor in its documented limits)

n ", i"<n<n _m ax, (n _m in, ni, nmax, - variable ratio of recycle gas to raw material in its documented limits). Example: 1000- 1800 HM ^{^3/3}

Ok = Oko, (Ok, Oko - produced and given octane number)

Gniiii <Gi <Gmax- (G _m, G i, Gma - variable volume utilization of the reactor unit to the input gas mixture (feed) in his documented limits) Q - Volume consumption of recycle gas at the inlet of the reactor unit

/ - value within the limits of variation

Ti, Pj, can be given a separate value for each reactor of the unit.

In a fourth step, the reactor is set to run with the optimized operating parameters, namely, among other things, with specifically different working gas temperatures at the inlet of each reactor.

The constant characteristics of the plant include the plant geometry, the composition of the catalyst, other properties of the physical plant components (eg the type of plant (fixed bed reactors vs. CCR plant, presence of one or more compressors, flow through the reactors, The constant properties are thus very specific properties of the present system to be simulated, which are determined on the basis of measurements or on the basis of existing installation-specific specifications (for example plans, catalyst specification, etc.) and not merely generic as in the prior art Values that apply, for example, for each component of the generic type.

Operating parameters are at least partially adjustable variables such as pressure, temperatures, material flow through the reactors, flow rate of recycle gas (specifically: flow rate of molecular hydrogen, besides this, the recycle gas may have further constituents, for example nitrogen, noble gases, etc.). An optimization method for a plant of the type mentioned therefore has the following process steps:

Recording specific constant characteristics and operating parameters of the system,

Simulation of the chemical processes in the reactors in a first phase, taking into account different conditions in the different reactors, and in addition to the constant properties and the given operating parameters (eg pressure, temperature, material flow through the reactors) also a measured chemical composition of the on the output side of the last reactor resulting product or a subset of the product is included in the simulation,

- In a second phase, simulation of the chemical processes in the reactors with varied operating parameters, wherein in addition to the flow rate of recycle gas (or of molecular hydrogen as part of the recycle gas) and the temperatures of the working gas at the input of each reactor are set individually as operating parameters, and as a result of the simulation, a chemical composition of the product is calculated.

From the results of the second phase, a set of optimized operating parameters is determined, in particular by manually or automatically using predetermined criteria, the calculated chemical compositions are compared in terms of a specific objective and those operating parameters are selected, which bring the best results in terms of the objective , The erfmdungsgemäße use of the reactor inlet temperatures as control variables independently proves to be particularly advantageous for the optimization. It allows a concrete operation adapted to the reaction kinetics in the respective reactor, taking into account the fact that the composition of the working gas differs from reactor to reactor.

Another operating parameter is the pressure. In embodiments, if the plant is equipped accordingly (for example, by a compressor is available per reactor), the pressure is individually, different per reactor, set as operating parameters. This possibility arises in particular in fixed bed reactors but also in CCR systems with side-by-side arrangement of the reactors.

In particular, the method is accomplished offline, i. the mentioned data (constant properties, operating parameters, measurement results) are collected once, after which the further steps are carried out without the feedback from the system being required for the further steps. Although online regulations give the impression that they can respond more quickly to changes and that the possibilities offered by the available computer services are high, an offline solution turns out to be advantageous in the present context.

On the one hand, because of this procedure, high-resolution gas chromatographic analyzes can be used without having to pre-group into roughly grouped substances due to the required speeds. In control systems of the prior art, the results of gas chromatography generally have to be available within about 5 minutes, which is why only consideration of very broad substance groups, for example, from a single-digit number of substance groups is possible. It has been shown, however, that taking into account a larger number of substance groups present in the working gas - for example without pre-grouping, ie taking into account the full accuracy of the gas chromatograph and / or in a substantial number of in particular at least 30 substances and substance groups - an improvement not only Accuracy in describing the processes in progress, but also allowing optimization with an effective, measurable improvement in the efficiency of the whole system.

This does not rule out that the measured and injected substances / substance groups can be summarized by the model in subgroups that are meaningful for the simulation.

On the other hand, not least because of the size of conventional systems and the corresponding inertia, it is apparent that an offline solution is better suited to determining an optimal state of equilibrium than a regulation with feedback.

In embodiments, therefore, the aforementioned steps are taken offline, without measuring steps taken during the simulation steps and entered again into the calculation. Additionally or alternatively, as mentioned, the results of a gas chromatographic analysis without pre-grouping are taken into account. In contrast to the prior art, the gas chromatography data are therefore not used directly as a feedback signal for controlling the process (it is, of course, not excluded that this happens in addition to the procedure according to the invention), but indirectly, via the described process, in which optimization (second Phase) the measured data is not more directly. This less direct-acting process has proven to be advantageous. This is because a closer consideration of the reaction kinetics is possible and overall results in a more reliable and more robust simulation of the equilibrium state. The customizable operating parameters may include:

- The temperature of the working gas at the entrance of each reactor (individually selectable, for example, slightly increasing from reactor to reactor);

- The pressure; optionally different from reactor to reactor, if the system allows it - The feed rate (i.e., amount of naphtha per unit time)

- The amount of Fh gas per unit time.

The actual simulation steps are characterized in particular by the fact that the reaction kinetics is taken into account with real data obtained from the plant and taking into account the properties of the catalyst, whereby the residence time of the gas molecules at the catalyst surface can also be considered. They therefore differ from statistical methods known from the state of the art, in which on the basis of empirical values and data of different type-like systems it is attempted to estimate the operating parameters for a given system.

The chemical processes in a reactor for katalvtische reforming are known per se, and as such not part of the present invention, as well as the relevant formulas for the corresponding kinetics. They are therefore not reproduced again at this point, instead, for example, the lexicon of chemistry, keyword "reforming" (1998 Spektrum Akademischer Verlag, Heidelberg, currently available on the Internet at http://www.spektrum.de/lexikon/chemie/reformieren/7875) or referenced in general the technical literature.

Also, methods for performing computational simulations of catalytic reforming are already known and as such are not the subject of the present invention. An example is the publication by A. Askari et al., Petroleum & Coal 54 (1), 76-84 (2012). References 2-12 and Chapter 2.1 refer to underlying kinetic models.

In embodiments, for the simulation - in the first and in the second phase - the volume of the respective reactor is divided into a plurality of coaxial hollow cylinder volumes. Thus, the generally generally at least partially rotationally cylindrical geometry of the reactors and the flow conditions is taken into account - the flow of the working gas in the reactor is in each case from the outside to the inside through the catalyst or possibly from the inside to the outside.

For the simulation, the concentrations of gas quantities of substances and / or groups of substances in the working gas are assumed to be constant per cylinder volume, but potentially different from the volume of the wooden cylinder to the volume of the wooden cylinder. There may also be a potentially different temperature in each hollow cylinder volume than in the adjacent hollow cylinder volumes. The chemical reactions are applied in particular, for example, at least 30 groups of substances, in which the existing (and measured) substances are summarized. In the first simulation phase, in particular, model parameters are adjusted, with both the constant properties of the reactors and the operating parameters at which the measurement was taken as constants. Model parameters may be purely phenomenological (eg, coefficients, without specific physical properties, in equations or formulas), or they may have a physical meaning (eg, characterize flow resistance, etc.). In embodiments, both purely phenomenological and physical parameters are present. For the purpose of adapting the model parameters, for example, based on a set of model parameter starting values based on experience with other systems, a simulation of the chemical reactions is carried out and then the product resulting from the reaction is compared with the product effectively characterized by the measurement. Then, starting from the starting values, the model parameters are systematically varied in order to match the calculated result as far as possible with the measured values. As soon as, quantitatively defined in an abort criterion, the properties of the product according to the simulation are sufficiently close to the measured properties, the first phase is terminated and the model parameters with which this correspondence is reached are stored. They serve as constants in the second phase of the simulation process, in which the operating parameters are varied.

It is easy to find a measure of how close the product's actual and calculated properties are to each other. Mathematically, for example, the concentrations of the substance groups can be represented as a vector of a multidimensional vector space, and in this vector space a metric can be defined, for example a Euclidean metric, if necessary with special weighting of the components, more important for the product properties or even in small concentrations occurring components can be weighted more heavily than others. After completion of the first phase, for example, a computer program can be generated, which contains the simulation program used for the first phase in the core, but which contains the model parameters as non-variable constants, the operating parameters are changeable. Such a computer program is a plant-specific program which accordingly includes a plant-specific adapted physical / chemical model. It can be handed over to the operator of the system, for example in compiled and / or encrypted form.

In the second phase, simulations with varied operating parameters but constant model parameters are carried out for the purpose of process optimization. There is both the possibility of an automatic parameter search - i. the computer program, which executes the second phase of the method, systematically controls the operating parameters by a corresponding algorithm - or it can also be a manual adjustment of the parameters by the user, then the actual simulation with the user-selected operating parameters of course with technical Tools, so done by a computer. The selection of the optimized operating parameters, with which the system is then effectively operated, can be based on predetermined optimization criteria, for example. Weightings of the value achieved by optimizations of various sizes (octane, fh yield, reformate yield, LPG yield, production of aromatics, reduction Katalysatorverkokung, etc.) automatically or manually done by the operator.

The calculation methods according to the approach of the present invention are necessarily carried out computer-aided and require a large computing power. But since they are especially offline feasible, there are only very generous minimum requirements for the computer power. It can be a generic one modern, powerful computer system, especially with multiple processors or processor cores used.

The present invention also relates to a computer program for carrying out the method described here.

Furthermore, it also relates to an installation-specific computer program which contains the results of the first phase as fixed, no longer adaptable parameters and in which the operating parameters are automated or manually adjustable to perform the second phase of the simulation. In particular, the system-specific computer program may contain the parameters in encrypted form.

Both the computer program for carrying out the entire optimization process and the plant-specific computer program may be equipped in any aspect and for any embodiment of the invention described herein, i. All statements made in this text and relating to the method are also applicable to the computer programs.

The invention also relates to an operating method for a plant of the type discussed above for catalytic reforming, wherein different temperatures of the working gas at the entrance of each reactor are deliberately set differently, in particular due to the result of simulations, in particular according to the optimization method described in this text.

Hereinafter, some principles and embodiments of the present invention will be described with reference to drawings. Show it: Fig. 1 is a schematic cross-sectional view through a reactor;

schematically, also in cross-section, the subdivision coaxial hollow cylinder volumes;

3 is a simplified diagram of a plant with fixed bed reactors;

Fig. 4 is a still more simplified schematic of a CCR system;

a simplified flowchart

Simulation process; and

a simplified flowchart of the second phase simulation process.

1 schematically shows the principle of a reactor 1. In an outer vessel 2 with an inlet 3, a volume is formed between an outer gas-permeable wall 5 and an inner gas-permeable wall 9 which is at least partially filled with a catalyst 6. The working gas flows through the outer gas-permeable wall 5 into this volume and out through the inner gas-permeable wall 9 again (the flow direction is symbolized by the block arrows 7), an operation with flow in the other direction, from inside to outside, is not locked out). On the way through the volume molecules present in the working gas are repeatedly absorbed on the surface of the catalyst and desorbed from there. The residence time at the catalyst surface depends on the temperature, and the adsorption rate as well the flow paths depend on temperature and pressure; both have an influence on the reaction kinetics. In addition, the properties go - including the current state; Degree of coking etc. of the catalyst in the reaction kinetics.

According to the invention, it is now proposed, as mentioned, to model the reaction kinetics on the basis of the known chemical reactions, in particular to model offline, and based on the model the modifiable parameters "operating temperature per reactor", "pressure, in particular per reactor", "flow "and" feed / recycle gas ratio ".

The chemical reactions during catalytic reforming can be divided into three main groups:

a) Dehydration of naphthenes in aromatics

b) Dehydration and cyclization of paraffins in naphthenes

c) hydrocracking of napthenes into short paraffins

This results in a linear system of equations.

In a manner known per se, the kinetics of these reactions can be modeled on the basis of the law of mass action, depending on the pressure and the prevailing temperature as well as on the activity of the catalyst. The temperature, the concentrations of the individual reactants in the working gas and, to a certain extent, the pressure also depend on the position within the reactor. According to one aspect of the invention, it is proposed to take this into account by dividing the volume filled with the catalyst 6 in the model into ring partial volumes, which is shown schematically in FIG. Fig. 2 shows, as in Fig. 1 in horizontal section, schematically, the coaxial hollow cylinder volumes 1 1, for example, each have an equal thickness. Other divisions of the hollow cylinder volume sizes, for example. By the volume contents are chosen the same, resulting in different thicknesses are not excluded.

The parameters which are included in the modeling - for example temperature T and concentrations Ck of the various substances in the working gas - and possibly also the pressure P can each differ from hollow cylinder volume to hollow cylinder volume (index i). In particular, in the gas flow direction shown (FIG. 1), the temperature can decrease from the outside to the inside because the reactions taking place in the reactor are endothermic in the end.

Figure 3 shows a plant of semi-regenerative type (ie regeneration of the catalyst in the plant is possible, but only with shutdown of the reactor in question). The plant has three successive reactors 1, namely fixed-bed reactors 1.1, 1.2, 1.3. This is preceded by a respective conditioning device (which does not have to be physically configured as a unit and, for example, may have a plurality of separate elements) 21.1, 21.2, 21.3. Such has in each case a regulated working gas heater and a pumping device (generally a compressor, if necessary, a pump for still liquid portions may be present) on. In embodiments of the system, not every conditioning device has a heater, but, for example, only one of them. In Fig. 3, therefore, the pump symbols of Conditioning devices 21.2, 21.3 dashed lines for the second and third reactor, ie shown as optional.

The working gas A is the input side of a - already brought by heating in the gaseous state or in the first conditioning device 21.1 still evaporated feed F - and the recycle gas K formed. It is successively passed through the three reactors 1.1, 1.2, 1.3, changing its composition. The resulting after the last reactor 1.3 reforming product P is after its cooling (corresponding heat exchangers and coolers may be formed according to the prior art and are not shown in Fig. 3) a gas separator 26 is supplied. The non-volatile components R (reformate) are then fed to further processing steps which may correspond to the prior art and are not further elaborated here. The resulting volatile components G, which are rich in molecular hydrogen, are split in a splitter 27 by mixing as much gas as the recycle gas K is again mixed upstream with the feed F as necessary for the desired processes. The rest of the gas G is discharged and recycled as needed.

A control device 24 controls the conditioning devices 21,1, 21.2, 21.3, wherein a control circuit can be present in a manner known per se, in that the conditioning devices have a temperature and / or pressure and / or flow measurement and the control device is set up to adjust the corresponding devices of the conditioning device so and readjust if necessary. that a predetermined appropriate size (temperature / pressure / flow, etc.) is achieved. In its structure, the system can be constructed as a whole analogous to already known generic systems. It differs from the prior art but in particular at least as the control device 24 is set up.

On the output side of the last reactor (directly to the last reactor or later, before or after the gas separator 26), a gas chromatograph 31 is present, the output 32 flows into the operating data, which are used in the manner described below for the control of the system , The indirect influence of the measured data M on the control device 24 according to the procedure described here is represented by the box 33 in FIG. 3.

Figure 4 shows very schematically (without representation of Steuerimgseinrichtung and the gas chromatograph) a variant in which the system is designed as a regenerative system and the reactors 1.1, 1.2, 1.3 are arranged one above the other, so that the catalyst as illustrated by the block arrows very schematically is transported slowly through the reactors due to gravity during operation: after removal from the last reactor, the catalyst is regenerated; Regenerated catalyst material is continuously supplied to the first reactor 1.1 during operation.

From the plant of the type shown in Figure 3, such a system differs in particular also by the fact that due to the exchange of catalyst material, the operating pressures of the reactors can not be controlled independently of each other. Therefore, the second and third conditioning means 21.2. 21.3 drawn in Figure 4 without independent pumping means. The systems shown schematically and simplified in FIGS. 3 and 4 are to be understood as examples only. The procedure according to the invention also applies to other systems, for example systems with more (or possibly less) than three reactors, regenerative systems with reactors arranged side by side (and a transport system for the catalyst set up for this purpose), etc.

FIG. 5 shows a sequence of the first phase of a process optimization method. "St" denotes the beginning of the process, in a first step C, the constant real parameters of the plant (geometry of the reactors, filling quantity, etc.) are read in. Then (step B) the operating parameters, as in the plant before the process optimization The operating parameters include the process pressure, the process temperature, the circulating gas flow, etc. The measured data M are then read in, namely the data on the composition of the product P or the reformate R obtained by the gas chromatograph (see FIG In contrast to control systems according to the prior art, the entire gas chromatogram is taken into account within the resolution accuracy of the gas chromatograph, ie there is no pre-grouping of the compounds, as is done according to the prior art, to obtain the necessary analysis speed.

In a next step Par, model parameters are selected (step Par). For example, the initial model parameters may always be the same, or they may be roughly estimated by the operator or software based on the data (constants, operating parameters, measurements). Thereupon, a simulation S with the model parameters is performed, and the deviation of the values produced by the model from the measured values is quantified (step A). If the deviation does not correspond to a termination criterion (ie if the deviation is greater than a predetermined value, branch point K), the model parameters are adjusted (back to step Par). and a new simulation takes place. This will be for so long performed until the model parameters produce a sufficiently small deviation from the real data. As soon as the abort criterion is met (K), the current, successful model parameters are stored (Sa) and the first phase of the process optimization process is completed (Stp).

The result of the first phase can be implemented, in particular, in a method tailored to a specific installation in the form of software, with the stored model parameters. In this software operating parameters can then be automated or manually adjusted in test series by specialized users of the inventive approach or the Anlagenbetrieber.

FIG. 6 shows the second phase of the process optimization method. First, the constants and the operating parameters are read in again (steps C, B), whereby these can also be taken over by the first phase of the process optimization method. Also taken over are the model parameters MP determined and stored in the first phase of the process optimization method (step Sa). Then a simulation (step S) takes place and the results are analyzed (step An) with regard to the optimization to be carried out. If optimization potential is still detected (branch point O), a modification of the operating parameters takes place (ModB), whereupon it is simulated again. This process is repeated so long by systematic variation of the operating parameters until no appreciable optimization potential exists. Only then are the operating parameters identified as optimized stored (Sa ') and output, which terminates the second phase of the process optimization process.

Specifications for the optimization can be: - Increasing the yield of reformate increasing the octane number

Increasing the yield of molecular hydrogen Increasing the yield of LPG - Increasing the production of certain aromatics

Increasing the life of the catalyst (less coking)

The specifications each relate to the comparison with the operation without the process optimization. These requirements are partly in conflict with each other, and it may depend on specific needs, which is the priority of the specifications and in which the requirements can possibly be accepted that it is hardly or not at all implemented. It has been shown, however, that to a certain extent due to the optimization potential for many systems, all or at least almost all of the specifications can be implemented, with increases in the single-digit percentage range or - in the life of the catalyst - higher.

Subsequently, in a further step process optimization process, the plant is operated with the adjusted operating parameters. For this purpose, a slow, controlled adaptation takes place. This can be automated or done manually by operating personnel by operating the control device 24.

In principle, there is the option, after the last step of the process optimization process, of carrying out the process optimization method once again beginning with the first phase in order to include the model parameters Adjust measurements in the optimized state once more (in the first phase) and, with adapted model parameters, determine once again whether there is any further optimization potential. However, this is generally not necessary because the model is robust in terms of adjustment of operating parameters.

Example: For a plant with three fixed-bed reactors, example calculations for the optimum regime of the catalytic re-forming process were carried out according to the method according to the invention. The following table shows extracts:

In this table, Q (in 10 ³ nr '/ h) denotes the volume consumption of recycle gas, T' the temperature at the inlet of the respective reactor, G the feed (in m ³ / h);

corresponding to Q, and Ok the octane number. By optimization, the yield of reformate could be increased by 3-5% compared to a base regime, by means of optimization based on a yield of 78-82% o (base regime) a yield of 83.1-85.6%) was achieved.

Thus, the designated model for multi-parameter optimization of catalytic reforming has the following advantages over other process optimizations:

Increasing the effectiveness of the catalyst used by using technologically related areas of the reaction zone, which previously participated incomplete in the reactions.

- Increasing the product output by 3-5% (up to 8% possible) as well as improving its quality by ensuring a uniform hydrodynamic resistance throughout the catalyst area while increasing the ratio of active

Catalyst area to the mass of Paragasgemiscb.es which flows through it.

- Influence on the kinetics of the thermochemical reactions within the Paragasgemiscb.es during contact with the catalyst by determining and selecting optimal operating parameters of the reformer unit in the selected ring volumes.

Claims

A method for optimizing the operation of a catalytic reforming plant comprising a plurality of catalyst-containing reactors through which a working gas containing hydrocarbons and molecular hydrogen successively flow, wherein the composition of the working gas in the reactors changes and the downstream a product results from the last of the reactors, which method comprises the following steps:

Detecting specific constant characteristics and initial operation parameters of the plant during operation.

Computational simulation of chemical processes in the reactors in a first phase, taking into account different ratios in the different reactors, and wherein in addition to the constant characteristics and the detected initial operating parameters and results of a measurement of the chemical composition of the output side of the last reactor resulting product or a Subset of this product goes into the simulation,

Computational simulations of the chemical processes in the reactors with different, varied operating parameters in a second phase following the first phase, taking into account results of the first phase, wherein as varied operating parameters in addition to a flow rate of molecular hydrogen and different temperatures of the working gas at the entrance of each reactor be set individually, and as a result of the computational simulation, a chemical composition of the product (which is dependent on the operating parameters) is calculated, Determining a set of optimized operating parameters from second phase results.

2. The method of claim 1, wherein in the second phase and a working pressure in a reactor is varied as an operating parameter.

The method of claim 2, wherein in the second phase as varied operating parameters also different pressures in each reactor are set individually.

Method according to one of the preceding claims, wherein the computational simulations in the first and in the second phase are performed offline.

5. A method according to any one of the preceding claims, wherein the measurement of the chemical composition includes a gas chromatographic analysis.

6. The method of claim 5, wherein for the first phase, the results of the gas chromatographic analysis are detected without pre-grouping.

7. The method according to any one of the preceding claims, wherein for the simulation in the first phase, both the constant properties of the reactors and the operating parameters are kept constant, depending on model parameters as a result, a calculated chemical composition of the product is determined and compared with the results of the measurement becomes, and that the simulation is repeated with systematically varied mode parameters until the deviation of the calculated chemical composition of the product from the results of the measurement corresponds to an abort criterion, whereupon those model parameters with which the abort criterion was reached are considered to be constant in the second phase

Model parameters are stored.

8. The method according to any one of the preceding claims, wherein after completion of the first phase, a computer program is generated, which contains a simulation program for the simulation in the second phase and has determined in the first phase model parameters as constants.

9. The method according to any one of the preceding claims, wherein in the second phase, the operating parameters are varied systematically in order to optimize the product according to predetermined optimization criteria.

10. The method according to any one of the preceding claims, wherein for both the first simulation and for the second simulation, volumes of the reactors are divided into coaxial hollow cylinder volumes, and that for the simulation, the concentrations of gas quantities of substances and / or groups of substances in the working gas per cylinder volume constant but potentially different from wood cylinder volume to wood cylinder volume.

A method of operating a catalytic reforming plant comprising a plurality of catalyst-containing reactors, one after another, of hydrocarbons and molecular hydrogen flowing through the working gas containing. wherein the composition of the working gas changes in the reactors and the output side of a last of the reactors results in a product, the plant is initially operated constantly with initial operating parameters, and then the method according to one of the preceding

Claims is carried out, and then the operation of the system is replaced by replacement of the initial operating parameters by the optimized operating parameters.

A method, in particular according to claim 1 1, for operating a plant for catalytic reforming, which plant has a plurality of catalyst-containing reactors, which are flowed through by a success of a hydrocarbon and molecular hydrogen-containing working gas, wherein the composition of the working gas in the reactors and wherein the output side of a last of the reactors results in a product, wherein different temperatures of the working gas are set differently at the inlet of each reactor.

Computer program which can be loaded onto a data processing device or a system of data processing devices and which, when executed, allows the data processing device or the system of data processing devices to execute a method according to one of Claims 1-10.

14. A data carrier containing a computer program according to claim 13. An equipment-specific computer program for optimizing the operation of a catalytic reforming plant comprising a plurality of catalyst-containing reactors through which a working gas containing hydrocarbons and molecular hydrogen successively flow, wherein the composition of the working gas in the reactors changes and the output side resulting in a product of the last of the reactors, the computer program being loadable on a data processing device or a system of data processing devices and adapted to perform a computational simulations of the chemical processes in the reactors with different, varied operating parameters to calculate a chemical composition of the product, and wherein Computer program is specifically designed for the plant by containing model parameters that are the result of a computational simulation of chemical processes in the reactor ren, in which different conditions in the various reactors are taken into account, and in which besides constant properties and detected initial operating parameters also results of a measurement of the chemical composition of the output side of the last reactor resulting product or a subset of this product have been included in the simulation.

16. A data carrier containing a computer program according to claim 15.