CN115808401A - A Rapid Analysis Method for Acid Center Accessibility in Porous Solid Particles - Google Patents

Abstract

The invention relates to a method for rapidly analyzing accessibility of acid centers in porous solid particles, which comprises the following steps: s1, preparing an alkaline probe molecular solution by adopting an organic alkaline compound and a solvent, and putting the alkaline probe molecular solution into a stirring container of an analysis testing system, wherein the analysis testing system can analyze and detect the concentration of the organic solution in real time under an anhydrous condition; s2, starting a testing system, quickly adding 0.1-10 g of a catalyst sample to be tested into the stirring container after a signal to be tested is stable, and continuously monitoring the change of the detection signal in real time; and S3, obtaining an adsorption rate curve of the alkaline probe molecule solution according to the detection signal obtained by real-time monitoring, wherein the initial slope of the curve is a parameter for judging the accessibility of the catalyst acid center, and the adsorption quantity corresponding to the platform of the curve is a parameter for judging the total accessibility of the catalyst acid center. The method is suitable for rapid analysis of the accessibility of the acid center of the porous solid acid catalytic material.

Description

A Rapid Analysis Method for Acid Center Accessibility in Porous Solid Particles

technical field

The invention belongs to the field of petrochemical catalyst research, in particular to a rapid analysis method for the accessibility of acid centers in porous solid particles.

Background technique

Heavy oil processing technology can convert heavy oil into high value-added products, how to maximize the conversion of heavy oil molecules into small molecular compounds has become an important research topic in the field of petroleum refining. Fluid catalytic cracking (FCC) technology is the core technology for processing heavy oil in refineries. The accessibility of active centers (acid centers) in FCC catalyst particles to heavy oil molecules is the key to restricting its conversion efficiency. Therefore, rapid analysis of acid site accessibility within catalyst particles is of great significance for catalyst development and evaluation of catalyst performance during use.

At present, the evaluation of the acid performance of solid acid catalysts mainly uses n-butylamine titration (C.Walling, J.Am.Chem.Soc.72 (1950) 1164-1168.), pyridine adsorption in-situ infrared spectroscopy ( Py-FTIR) (TheJournal of Physical Chemistry, 1982, 86(10): 1760-1763; Journal of Catalysis, 1984, 89(2): 185-195), ammonia temperature programmed desorption technology (NH ₃ -TPD) (Zeolites, 1984, 4(1): 9-14.), study information such as acid type, acid amount and acid strength distribution. However, although the accessibility of acid sites as a key factor affecting the performance of FCC catalysts has attracted the attention of researchers, due to the lack of a fast and convenient analysis method, the accessibility of acid sites still cannot be used as the key to evaluate catalyst performance. parameter.

The method that can be used to study the accessibility of acid centers of solid acid catalysts is in-situ infrared spectroscopy. N.S.Nesterenko et al. Alkylpyridines were used as probe molecules to study the accessibility of acid centers in the channels of mordenite. However, this method has several disadvantages: first, the above-mentioned in-situ infrared spectroscopy requires harsh experimental conditions under vacuum conditions, and the experimental process is cumbersome, and the analysis of a group of samples takes 2-3 days, which is not suitable for rapid analysis; The reason is that this method requires the sample to be ground and pressed into tablets, so this method is not suitable for the analysis and determination of the accessibility of the acid centers in the shaped catalyst particles; the third is that the method requires the selected basic probe molecules to have a higher saturated vapor pressure , so it is not suitable for evaluating macromolecular basic compounds that can simulate heavy oil molecules; Fourth, because infrared spectroscopy is a semi-quantitative method, this method cannot accurately quantify the accessibility of acid centers. However, the use of in-situ infrared spectroscopy also has the disadvantage of relatively expensive infrared accessories and infrared spectrometers, which is not suitable for widespread promotion.

CN1513112A discloses a method and device for detecting the accessibility of porous materials to large compounds. The invention relates to a method for detecting the accessibility of porous materials to large compounds with generally high molecular weight and comparing the accessibility of porous materials with the Approaches associated with accessibility under conditions. The method disclosed in this invention only pays attention to the accessibility of macromolecular compounds to the pores of the catalyst, and the macromolecular compounds are non-basic compounds, which cannot realize the evaluation and analysis of the accessibility of catalyst acid centers.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a rapid analysis method for the accessibility of acid centers in catalyst particles. This method is suitable for the rapid evaluation of the acid performance of catalysts in the analytical departments of petrochemical research institutes and petroleum refineries.

For this reason, the present invention provides a kind of rapid analysis method of acid center accessibility in porous solid particles, comprising the following steps:

S1. Using an organic basic compound and a solvent to configure a basic probe molecular solution, and putting the basic probe molecular solution into a stirring container of a test system, the test system can analyze the concentration of the organic solution in real time under anhydrous conditions;

S2. Turn on the test system, and after the detection signal is stable, quickly add the sample to be tested into the stirring container, and continue to monitor the change of the detection signal in real time;

S3. According to the detection signal obtained by real-time monitoring, the concentration of the corresponding alkaline probe molecule solution is obtained, and then the real-time adsorption amount of the sample to be tested is calculated for the alkaline probe molecule, and then obtained by plotting the real-time adsorption amount and the square root of time The adsorption rate curve of the alkaline probe molecule solution, the initial slope of the curve is a parameter for judging the accessibility of the acid center in the sample to be tested, and the adsorption amount corresponding to the platform of the curve is the parameter for judging the accessibility of the acid center in the sample to be tested. parameters close to the total.

In the rapid analysis method of the present invention, preferably, the test system includes: a stirred container capable of water vapor isolation, an online analysis detector for the concentration of an organic solution, a circulating pump, and pipe fittings connecting the above components.

In the rapid analysis method of the present invention, preferably, the stirred container capable of water vapor isolation is a container protected by an atmosphere of an inert gas (a gas that does not react with the sample to be tested and the alkaline probe molecular solution) , the volume of the container is 50-500ml.

In the rapid analysis method of the present invention, preferably, the online analysis detector for the concentration of the organic solution is an ultraviolet or fluorescence detector equipped with an in-situ cell.

In the rapid analysis method of the present invention, preferably, the in-situ pool is a cuvette, and the volume of the cuvette is 5 μl-1.5ml, preferably 50-500 μl.

In the rapid analysis method of the present invention, preferably, the circulating pump is a small-volume peristaltic pump or a plunger pump with a stable flow rate.

In the rapid analysis method of the present invention, wherein preferably, the basic probe molecules in the basic probe molecule solution comprise basic organic compounds with pyridine nitrogen and amino nitrogen groups, preferably selected from quinoline, At least one of acridine and naphthylamine molecules.

In the rapid analysis method of the present invention, wherein preferably, the solvent in the basic probe molecule solution is a non-polar organic solution, preferably selected from C7-C10 normal or isoparaffins or mixtures thereof, C6- At least one of C8 aromatic hydrocarbons or mixtures thereof, carbon tetrachloride, chloroform and _CS2 .

In the rapid analysis method of the present invention, preferably, the concentration of the basic probe molecule solution is 10 ^-9 to 10 ^-2 mol/L, more preferably 10 ^-7 to 10 ^-2 mol/L, more preferably It is further preferably 0.1-10 mmol/L; the sampling amount of the sample to be tested is 0.1-10 g, more preferably 0.5-2 g.

In the rapid analysis method of the present invention, preferably, the porous solid particles are spherical granular porous solids with a particle diameter of 5-150 μm.

In the rapid analysis method of the present invention, preferably, the porous solid is an FCC catalyst, and the FCC catalyst includes fresh FCC catalyst, used FCC catalyst and deactivated FCC catalyst.

In the rapid analysis method of the present invention, preferably, the porous solid is a porous solid acid catalyst, and the porous solid acid catalyst needs to be dehydrated first, and more preferably the dehydration temperature is 100-350 ℃.

The rapid analysis method for the accessibility of acid centers in porous solid particles disclosed by the invention has the advantages of fastness, convenience and low price.

The rapid analysis method for the accessibility of acid centers in porous solid particles disclosed by the present invention, the method specifically includes the following steps:

Step 1: Preparation of analytical instruments and reagents

This method requires a set of analysis and testing system capable of real-time analysis and detection of changes in the concentration of alkaline probe molecule solutions under anhydrous conditions. The analysis and testing system includes: a stirrable container isolated from air, a detector for on-line monitoring, a circulation pump, and Tubes connecting these parts.

Screen suitable organic basic compounds as basic probe molecules, and the basic probe molecules may include all basic organic compounds with pyridine nitrogen and amino nitrogen groups.

Step 2: Configuration of Analysis Solution

This method requires the basic probe molecules and solvents used to undergo strict dehydration and purification treatment, accurately weigh (measure) a certain mass (volume) of basic organic compounds, dissolve it in a small amount of solvent, and then move it into a volumetric flask for constant volume. Prepare a solution with a certain concentration and set it aside. The basic probe molecule solution of the present invention is a dilute solution, and the specific concentration depends on the dissolution of the selected solute in the selected solvent, and is specifically optional within the range of 0.1-10 mmol/L.

Step 3: Preparation of samples to be tested

This method requires that the particle size distribution of the sample to be tested is relatively narrow, so the catalyst sample needs to be sieved, and the selection of the particle size depends on the most probable particle size of the tested catalyst sample, specifically within the range of 5-150 μm. Optional; this method requires the sample to be tested to be activated, so the sample to be tested needs to be dehydrated first. The calcination temperature of the activation treatment depends on the actual calcination temperature of the sample to be tested, specifically in the range of 150-600 ° C It is optional, preferably at 150-350°C; and the sample is not exposed to water vapor during the whole experiment, and it is ready for use.

Step 4: Specific experimental operation process

First, quickly transfer the quantitative solution to the stirring container of the analysis and test system mentioned in step 1, turn on the circulation system, and turn on the detector to record the signal of the initial solution. After the detection signal is stable, quickly add the quantitative solution to be analyzed in step 2. To measure the sample, the sampling amount of the catalyst is 0.1-10g, preferably 0.5-2g, and continue to monitor the signal change in real time.

Step 5: Data result processing

According to the solution concentration corresponding to the detected signal recorded in real time, calculate the real-time adsorption amount of the basic probe molecule of the sample to be tested, and then plot the real-time adsorption amount and the square root of time to obtain the adsorption rate curve of the basic probe molecule solution , the initial slope of the curve is a parameter for judging the accessibility of catalyst acid centers, and the adsorption amount corresponding to the plateau of the curve is a parameter for judging the total amount of catalyst acid centers accessible.

A set of analysis and testing system capable of real-time monitoring of changes in the concentration of the alkaline probe molecule solution described in step 1, the stirred vessel capable of water vapor isolation is a round-bottomed flask or a self-made vessel protected by a nitrogen atmosphere, with a suitable volume 50-500ml.

A set of analysis and testing system capable of real-time monitoring of changes in the concentration of the alkaline probe molecule solution described in step 1, the specifically described online detector is an ultraviolet detector or a fluorescence detector, which requires the ability to automatically record data. During automatic detection, The counting frequency is not less than 1 time per second, which can ensure real-time online monitoring of changes in solution concentration. A UV spectrophotometer is preferred as the detector, the wavelength chosen depends on the nature of the probe molecule and solvent.

A set of on-line analysis testing system capable of real-time monitoring of changes in the concentration of the alkaline probe molecule solution described in step 1, the specific on-line analysis needs to be equipped with a special flow cuvette to achieve, specifically requires the selected cuvette The volume should be small, specifically 5 μl-1.5ml, preferably 50-500 μl, to ensure that the signal at the detector end can reflect the change of solution concentration as soon as possible.

A set of analysis and testing system capable of real-time monitoring of changes in the concentration of the alkaline probe molecular solution described in step 1, the specifically described circulation pump can be a small-volume peristaltic pump or a piston pump, and the flow rate of the pump is required to be stable and the delivery speed can be It is 1-50ml/min, to ensure that the signal at the detector end can reflect the change of solution concentration as soon as possible.

In step 1, a set of analysis and testing system capable of monitoring changes in the concentration of alkaline probe molecule solution in real time, in order to prevent catalyst particles from entering the detection system and interfering with the detection signal, the solution must be strictly filtered before leaving the stirring container.

A set of analysis and testing system capable of real-time monitoring of changes in the concentration of the alkaline probe molecular solution described in step 1, the circulation of the solution between the stirring container and the detector needs to be connected to the pipeline of the system, and the material of the connecting pipe is required to be oil-resistant and alkali-resistant. The size of the pipe diameter is selected according to the delivery speed of the pump, preferably 1-10mm, preferably 3-6mm.

For the specific processing of the data results described in step 5, a series of solutions with known concentrations should be prepared for the preferred basic probe molecules, and a standard curve should be drawn to obtain the corresponding relationship between the detection signal of the detector and the concentration of the solution. Therefore, the detection signal recorded in real time during the experimental analysis process can be converted into the corresponding real-time solution concentration, and the real-time relative concentration is plotted against the square root of time. The initial slope of the obtained curve can represent the adsorption of the sample to the probe molecule. Rate, this method defines the opposite number of the slope value as the parameter of the accessibility of the acid center of the sample to be tested, and is named as the ACI value, and the concentration value corresponding to the platform of the curve can be used to calculate the accessible total amount of the acid center of the catalyst.

The beneficial effects of the present invention are as follows:

The hardware price of the test device required by the technology of the present invention is low, the operation is simple, there is no special requirement for the operator, and a test can be completed within 30 minutes, and the acid center in the porous solid particle (such as porous solid acid catalyst, catalytic cracking catalyst particle) can be achieved. The rapid analysis requirements of proximity can be widely used in the rapid evaluation of acidic solid catalysts.

Description of drawings

Fig. 1 is the relative concentration variation curve of the four kinds of FCC catalysts (Cat-1, 2, 3, 4) adsorbed alkaline probe A-1 n-octane solution measured in Example 1.

Fig. 2 is the relative concentration variation curve of the four kinds of FCC catalysts (Cat-1, 2, 3, 4) adsorbed alkaline probe A-2 n-octane solution measured in Example 1.

Fig. 3 is the relative concentration variation curve of four kinds of FCC catalysts (Cat-1, 2, 3, 4) adsorbing non-alkaline probe NA-1 n-octane solution measured in Example 2.

Fig. 4 shows the acid site accessibility of two FCC catalysts (Cat-1, 4) measured by in-situ infrared spectroscopy in Example 5.

Detailed ways

The embodiments of the present invention are described in detail below: the present embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are provided, but the protection scope of the present invention is not limited to the following embodiments, the following The experimental method that does not indicate specific condition in the embodiment, generally according to routine condition.

Examples 1-1 to 1-4

Step 1: Preparation of analytical instruments and reagents

The analytical testing system capable of real-time monitoring of changes in the concentration of alkaline probe molecule solutions in this embodiment includes: a magnetic stirrer, a 250ml three-necked round-bottomed flask, a UV-1801 model UV-visible spectrophotometer, and a 25 μl flow cell colorimetric A dish, a peristaltic pump, a peristaltic pump hose with an inner diameter of 3 mm as a connecting pipe, a porous metal filter with a pore size of 1 μm, and a computer for real-time recording of the detection signals of the UV-Vis spectrophotometer. In this embodiment, acridine is selected as the basic probe molecule, and pure n-octane is used as the solvent for analysis.

Step 2: Configuration of Analysis Solution

The purchased analytical basic probe molecule A-1 (quinoline) and n-octane were all dehydrated with 5A molecular sieve, and a certain amount (see Table 1) of A-1 was accurately weighed, first dissolved in a small amount of n-octane, and then Transfer to a 1000ml volumetric flask, constant volume with n-octane, and prepare a solution with a concentration of 1mmol/l for later use.

Step 3: Preparation of Catalyst Samples

In this embodiment, a series of fresh FCC catalysts (Cat-1, 2, 3, 4 respectively corresponding to Examples 1-1 to 1-4) are selected as analysis samples, sieved, and 300-200 mesh (53-75 μm) is retained Samples (catalyst samples do not need to be crushed) were roasted and dehydrated at 350°C overnight, and the roasted samples were isolated from the air and cooled for later use.

Step 4: Specific experimental operation process

First, measure 100ml of the quinoline solution prepared in step 2 and add it to the 250ml three-necked flask extracted in step 1, replace the air with nitrogen to isolate water vapor, and turn on the peristaltic pump to start the circulation of the solution in the system. Use n-octane solution as a reference solution, set the spectrophotometer to 0, use 314nm wavelength to detect once per second and start recording the signal of the initial solution. After the detection signal is stable (about 10 minutes), set the Add 1g of FCC catalyst into the solution, turn on the magnetic stirring, continue to monitor the signal changes in real time, and record for 10 minutes.

Step 5: Data result processing, according to the absorbance signal value recorded in real time by the UV-Vis spectrophotometer, calculate the solution concentration value corresponding to each absorbance according to the drawn standard curve, and use the square root of the relative concentration and time to calculate the concentration of each catalyst For the ACI value of basic probe A-1, the obtained results are shown in Figure 1, Figure 2 and Table 1.

Table 1 is the ACI value and AAI value of each FCC catalyst calculated from the curves obtained in Figure 1, 2 and Figure 3, and the BAA value of the catalyst obtained by the in-situ infrared spectroscopy technique in Figure 4, and the average time spent to obtain each group of data Compared.

Examples 1-11

This example is basically the same as Example 1-1, except for the type and dosage of the basic probe molecule. The basic probe molecule A-2 refers to acridine, and its dosage is shown in Table 1.

Examples 1-21

This example is basically the same as Example 1-2, except for the type and dosage of the basic probe molecule. The basic probe molecule A-2 refers to acridine, and its dosage is shown in Table 1.

Examples 1-31

This example is basically the same as Example 1-3, except for the type and dosage of the basic probe molecule. The basic probe molecule A-2 refers to acridine, and its dosage is shown in Table 1.

Examples 1-41

This example is basically the same as Example 1-4, except for the type and dosage of the basic probe molecule. The basic probe molecule A-2 refers to acridine, and its dosage is shown in Table 1.

Comparative example 1-1

This comparative example 1-1 is basically the same as embodiment 1-1, the difference is:

The selected probe molecule of this comparative example is non-basic compound NA-1 porphyrin (the probe molecule used in this comparative example belongs to CN1513112A), calculates the accessibility index (AAI, Akso Accessibility Index) value of each catalyst, for Comparing the differences in the experimental results obtained by using basic and non-basic organic compounds as probe molecules, the results obtained in this embodiment are shown in Figure 3 and Table 1.

Comparative example 1-2

This comparative example 1-2 is basically the same as embodiment 1-2, the difference is:

The selected probe molecule of this comparative example is the non-basic compound NA-1 porphyrin (the probe molecule used in this comparative example belongs to CN1513112A), and the AAI value of each catalyst is calculated, which is used for comparing basic and non-basic organic compounds. As the difference of the experimental results obtained by the probe molecules, the results obtained in this embodiment are shown in FIG. 3 and Table 1.

Comparative example 1-3

This comparative example 1-3 is basically the same as embodiment 1-3, the difference is:

The selected probe molecule of this comparative example is the non-basic compound NA-1 porphyrin (the probe molecule used in this comparative example belongs to the published patent CN1513112A), and the AAI value of each catalyst is calculated for comparing basic and non-basic organic compounds As the differences in the experimental results obtained by the probe molecules, the results obtained in this embodiment are shown in Figure 3 and Table 1.

Comparative example 1-4

This comparative example 1-4 is basically the same as embodiment 1-4, the difference is:

The selected probe molecule in this embodiment is the non-basic compound NA-1 porphyrin (the probe molecule used in this embodiment belongs to the published patent CN1513112A), and the AAI value of each catalyst is calculated for comparing basic and non-basic organic compounds As the differences in the experimental results obtained by the probe molecules, the results obtained in this embodiment are shown in Figure 3 and Table 1.

Example 3

This embodiment is basically the same as Embodiment 1-1, the difference is:

The solvent used in this example is petroleum ether (90-120°C). By comparing the difference between mixed alkanes as solvent and n-octane as solvent, the results confirm that relatively cheap petroleum ether (90-120°C) can be used instead of n-octane alkanes as solvents.

Example 4

This embodiment is basically the same as Embodiment 1-1, the difference is:

The solvent used in this embodiment is xylene, compared the difference between aromatic hydrocarbon as solvent and n-octane as solvent, the results found that for the same catalyst sample, the ACI value obtained with xylene as solvent is relatively small, which can be considered as aromatic hydrocarbon solvent and n-octane. There is a certain competitive adsorption relationship between aromatic basic probe molecules on the catalyst.

However, for different catalyst samples, the order of ACI values obtained by using xylene as a solvent is consistent with the results obtained in Example 1. Therefore, in order to avoid the influence of solvent, a series of comparative experiments requires the use of the same solvent.

Example 5

This embodiment adopts in-situ infrared spectroscopy to test the acid center accessibility of a catalyst sample, using Frontier Fourier transform infrared spectrometer (U.S. Perkin-Elmer Company) supporting in-situ high vacuum adsorption and desorption device (Dalian Institute of Chemical Physics, Chinese Academy of Sciences) Made) completed (note: the equipment is expensive, and the maintenance is difficult and costly).

Sample preparation: firstly, the microspherical catalyst sample with a particle size of 100 μm needs to be ground into powder (note: the catalyst particles need to be crushed), and then pressed into two self-supporting sheets with the same quality as possible (15±0.5mg/ cm ² ) (this step requires a higher level of technical proficiency for the operator);

酸中心)的变化可计算此类酸中心的可接近指数(

Acidity accessibility,BAA值)。每个催化剂样品酸中心可接近性测试需要测试两个不同尺寸的碱性探针的红外数据，根据二者的比值，分别测得Cat-1和Cat-4的BAA值分别为0.55和0.30，每种碱性探针的测试过程至少需要8h，总时长16h。因此，一个催化剂样品的酸中心可接近性测试至少需要2个工作日，非常耗时。Acid center test: Two sets of the same vacuum system are required. First, the vacuum system is pre-evacuated for 2 hours, and the two sample pieces are respectively installed in a special quartz in-situ infrared absorption cell with a CaF2 window and heated to 673K by programming. Activation under vacuum (10 ^-3 Pa) for 4h, after naturally cooling to room temperature, adsorbed two kinds of basic probe molecules (A-4 pyridine and A-3 4,6-lutidine) for 1h respectively, and then Vacuum desorption at 150°C for 1 h, and scan its infrared spectrum after cooling down to room temperature. The characteristic bridging hydroxyl groups on the catalyst before and after the adsorption of basic probe molecules (3640cm ^-1 ,

Acid sites) changes can calculate the accessibility index of such acid sites (

Acidity accessibility, BAA value). The acid center accessibility test of each catalyst sample needs to test the infrared data of two basic probes of different sizes. According to the ratio of the two, the BAA values of Cat-1 and Cat-4 were measured to be 0.55 and 0.30, respectively. The testing process of each basic probe takes at least 8 hours, and the total time is 16 hours. Therefore, the acid site accessibility test of a catalyst sample takes at least 2 working days, which is very time-consuming.

Table 1

From Examples 1-1 to 1-4 using basic probe molecules and Comparative Examples 1-1 to 1-4 using non-basic probe molecules, compared to using non- The AAI index obtained by the basic probe molecule is more suitable for the ability to distinguish the accessibility of pores in different porous materials. The present invention uses two basic probe molecules with different molecular sizes to carry out the ACI index measurement, which can effectively distinguish different The difference in the accessibility of the acid center on the catalyst, such as the difference in the accessibility of Cat-1 and Cat-4 for the two probes A-1 and A-2 in Comparative Examples 1-1 and 1-4, illustrates This method is more effective than the comparison method, which is beneficial to analyze the accessibility of the catalytic active centers of porous catalysts, and provides guidance for the design of the catalyst.

By comparing the examples 1-1 to 1-4 using the basic probe molecule and the example 5 using A-3/A-4, the accessibility of the acid center on the catalyst that can be measured by the method provided by the present invention is illustrated The result is more consistent with the result provided in Example 5, but the time consumption of the analysis and testing process is greatly shortened, which fully reflects the rapidity and convenience of the method.

Figures 1 to 4 are explained as follows: Figure 1 and Figure 2 are the adsorption rate curves of basic probe molecules with different molecular sizes, and the difference in the adsorption rate is related to the number and accessibility of acidic sites in the catalyst pores. Figure 3 uses a non-basic probe NA-1 (porphyrin) provided in the comparative patent method as an adsorbate, and measures the difference caused by the difference in the pore structure of the catalyst sample to the adsorption rate of the probe molecule. Fig. 4 is the quantitative data of the accessibility of the acid centers of Cat-1 and Cat-4 catalysts to pyridine and 4,6-lutidine molecules, respectively, provided in Example 5.

Certainly, the present invention also can have other various embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes And deformation should belong to the protection scope of the present invention.

Claims (12)

1. A method for rapid analysis of accessibility of acid centers within porous solid particles, comprising the steps of:

s1, preparing an alkaline probe molecular solution by adopting an organic alkaline compound and a solvent, and putting the alkaline probe molecular solution into a stirring container of an analysis testing system, wherein the analysis testing system can analyze and detect the concentration of the organic solution in real time under an anhydrous condition;

s2, starting a testing system, quickly adding a sample to be tested into the stirring container after a signal to be tested is stable, and continuously monitoring the change of the detection signal in real time;

and S3, obtaining the concentration of the corresponding alkaline probe molecule solution according to the detection signal obtained by real-time monitoring, then calculating the real-time adsorption quantity of the sample to be detected to the alkaline probe molecules, and then drawing by the square root of the real-time adsorption quantity and time to obtain an adsorption rate curve of the alkaline probe molecule solution, wherein the initial slope of the curve is a parameter for judging the accessibility of the acid centers in the sample to be detected, and the adsorption quantity corresponding to the platform of the curve is a parameter for judging the total accessibility of the acid centers in the sample to be detected.

2. The rapid analysis method according to claim 1, wherein the analysis test system comprises: a stirring vessel capable of being isolated from water vapor, an on-line analysis detector for the concentration of an organic solution, a circulating pump, and a pipe fitting for connecting the above components.

3. The rapid analysis method according to claim 1, wherein the stirring container capable of being isolated from water vapor is a container protected by an inert gas atmosphere, and the volume of the container is 50 to 500ml.

4. The rapid analysis method according to claim 1, wherein the organic solution concentration online analysis detector is an ultraviolet or fluorescence detector equipped with an in-situ cell.

5. The rapid assay method according to claim 1, wherein the in-situ cell is a cuvette having a volume of 5 μ l to 1.5ml, preferably 50 μ l to 500 μ l.

6. The rapid analysis method according to claim 1, wherein the circulation pump is a small-volume peristaltic pump or a plunger pump with a smooth flow rate.

7. The rapid analysis method according to claim 1, wherein the basic probe molecules in the basic probe molecule solution comprise a basic organic compound having pyridine nitrogen and amino nitrogen groups, preferably at least one selected from quinoline, acridine and naphthylamine molecules.

8. The rapid analysis method according to claim 1, wherein the solvent in the basic probe molecule solution is a non-polar organic solution, preferably selected from the group consisting of C7-C10 normal or iso-alkanes or their mixtures, C6-C8 aromatic hydrocarbons or their mixtures, carbon tetrachloride, chloroform and CS ₂ At least one of (1).

9. The rapid assay method according to claim 1, wherein the concentration of the alkaline probe molecule solution is 10 ^-9 ～10 ^-2 mol/L, preferably 10 ^-7 ～10 ^-2 mol/L, more preferably 0.1 to 10mmol/L; the sampling amount of the sample to be detected is 0.1-10 g, and preferably 0.5-2 g.

10. The rapid analysis method according to claim 1, wherein the porous solid particles are spherical particle-shaped porous solids having a particle diameter of 5 to 150 μm.

11. The rapid analysis method of claim 1, wherein the porous solid is an FCC catalyst, and the FCC catalyst comprises fresh FCC catalyst, used FCC catalyst, and deactivated FCC catalyst.

12. The rapid analysis method according to claim 1, wherein the porous solid is a porous solid acid catalyst, and the porous solid acid catalyst is subjected to dehydration treatment, preferably, the dehydration treatment temperature is 100-350 ℃.

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