Catalyst

TECHNICAL FIELD

The present invention relates to the technical field of catalysts, particularly to a method and device for predicting the failure time of a desulfurization catalyst.

BACKGROUND ART

The natural gas fuel used in fuel cells contain sulfides. The presence of sulfides in natural gas will cause sulfur poisoning to the stack unit. Therefore, the sulfur compounds in the natural gas need to be removed through a catalyst before the natural gas enters the stack.

There are many kinds of desulfurization catalysts. Each desulfurization catalyst is mainly composed of an active component, a carrier and a co-catalyst. Among them, the active component is a main component of the catalyst. The carrier is a dispersant, binder or support of the catalytic active component, and serves as a skeleton carrying the active component. The co-catalyst is a small amount of substance added to the catalyst. It is an auxiliary component of the catalyst and does not have activity or has very low activity, but it can improve the activity, selectivity, stability and life of the catalyst. At present, the failure time of a desulfurization catalyst is generally obtained through an ageing test, and each influencing parameter needs to be tested, which takes a long time and requires a large workload of the operators, while the results are not predictive.

SUMMARY OF THE INVENTION

The present invention provides a method for predicting the failure time of a desulfurization catalyst. The method reduces the workload of the operators and saves time, and the test results are predictive.

The present invention further provides a device for predicting the failure time of a desulfurization catalyst. A first aspect of the invention provides a method for predicting the failure time of a desulfurization catalyst, comprising the following steps:

Step A, screening out a catalyst meeting a standard through a benchmarking test;

Step B, performing an ageing test on the catalyst screened at step A to determine a factor having a significant influence on the catalyst; and

Step C, performing a regression test on two factors including the factor having a significant influence on the catalyst and the ventilation time of the ageing test obtained at step B to obtain a regression equation of the factor having a significant influence on the catalyst and the ventilation time of the ageing test, and determining the failure time of the catalyst according to the regression equation.

Optionally, after step C, the method further comprises step D, correcting the regression equation in combination with the simulation results.

Optionally, after step D, the method further comprises step E, correcting the regression equation again through an actual test.

Optionally, at step A, the benchmarking test is performed on catalysts of the same volume.

Optionally, at step B, the ageing test is an accelerated ageing test under enhanced experimental conditions to simulate the desulfurization effect of the catalyst after hundreds or thousands of hours.

Optionally, the ageing test is a three-factor, three-level orthogonal experiment; and the enhanced experimental conditions include: increasing the concentration of a substance in the gas, accelerating the poisoning of the catalyst, and raising the working temperature of the catalyst.

Optionally, the enhanced experimental conditions include: increasing the concentration of sulfides in the gas, increasing the gas flow rate in the pipeline, and raising the temperature of the catalyst in the catalyst container or the gas temperature.

Optionally, the Gray correlation degree of the three factors is calculated from the detected desulfurization value of the three-factor, three-level orthogonal experiment, and according to the Gray correlation degree, it is determined that the concentration of sulfides in the gas and the gas flow rate in the pipeline have a significant influence on the sample gas detection result.

Optionally, the gas flow rate in the pipeline is increased to the maximum flow value allowed in the system, a regression test is performed on two factors including the concentration of sulfides in the gas and the ventilation time of the ageing test, and eventually, a regression equation of two factors including the concentration of sulfur compounds in the desulfurized sample gas or the concentration of sulfur compounds in the raw gas and the ventilation time of the ageing test is obtained.

Optionally, at step A, the standard is that the detection result of the sulfides in the sample gas from the benchmarking test meets IPPb.

A second aspect of the present invention further provides a device for predicting the failure time of a desulfurization catalyst. The device is used in the foregoing method and comprises a benchmarking test device and an ageing test device. The benchmarking test device comprises a first standard gas cylinder, the first standard gas cylinder is in communication with a plurality of sampling and detection lines arranged in parallel through a first pipeline, each of the sampling and detection lines comprises a first desulfurizer tank and a first sample gas cylinder in communication with each other through a second pipeline, the first desulfurizer tank is arranged adjacent to the first standard gas cylinder, and the first desulfurizer tanks on different sampling and detection lines are used for accommodating different catalysts. The ageing test device comprises a second standard gas cylinder, a second desulfurizer tank and a second sample gas cylinder, which are in communication with each other through a third pipeline. The second desulfurizer tank is used for accommodating a catalyst.

Optionally, a first pressure reducer is arranged on the first pipeline, and a first float flowmeter is arranged on the second pipeline in a position adjacent to the first standard gas cylinder. A second pressure reducer and a second float flowmeter are arranged on the third pipeline between the second standard gas cylinder and the second desulfurizer tank.

Optionally, the first desulfurizer tank and the second desulfurizer tank both comprise a drum body with openings at two ends, an upper end cover with a connection port is connected at an upper opening of the drum body, a pipe joint assembly is connected at a lower opening of the drum body, and a bed body for accommodating a catalyst is arranged inside the drum body. Optionally, the pipe joint assembly comprises a casing, an upper opening of the casing is connected to the drum body in a fixed manner, a first sintered metal mesh and a laser perforated board are arranged inside the casing, and the first sintered metal mesh is arranged adjacent to the drum body, and the lower end of the casing is provided with a connection opening.

Optionally, a second sintered metal mesh is arranged at the upper opening of the drum body.

From the foregoing technical solution, it can be seen that in the method for predicting the failure time of a desulfurization catalyst provided by the present invention, a catalyst meeting the standard is screened out through a benchmarking test at first and then an ageing test is performed on the screened catalyst rather than all catalysts, thereby avoiding ineffective work and saving a lot of time. A regression test is performed on two factors including the factor having a significant influence on the catalyst and the ventilation time of the ageing test to obtain a regression equation of the factor having a significant influence on the catalyst and the ventilation time of the ageing test. The failure time of the catalyst is determined according to the regression equation. By substituting the value of the factor having a significant influence on the catalyst into the regression equation, the failure time of the desulfurization catalyst is obtained directly when the value of the factor having a significant influence on the catalyst is changed, instead of performing a test whenever a value is changed, thereby saving time. Moreover, the regression equation obtained from the test results is predictive.

The present invention further provides a device for predicting the failure time of a desulfurization catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are briefly described below. The drawings in the description below are just some embodiments of the present invention.

Fig. l is a structural schematic view of a benchmarking test device.

Fig. 2 is a structural schematic view of an ageing test device.

Fig. 3 is a structural schematic view of a first desulfurizer tank and a second desulfurizer tank.

Fig. 4 is a structural schematic view of a pipe joint assembly.

DETAILED DESCRIPTION

The present invention discloses a method for predicting the failure time of a desulfurization catalyst. The method reduces the workload of the operators and saves time, and the test results are predictive.

The present invention further provides a device for predicting the failure time of a desulfurization catalyst.

Embodiments of the present invention will be described below in conjunction with the drawings. The described embodiments are only some, not all of the embodiments of the present invention.

The present invention provides a method for predicting the failure time of a desulfurization catalyst, comprising the following steps: step A, screening out a catalyst meeting a standard through a benchmarking test; step B, performing an ageing test on the catalyst screened at step A to determine a factor having a significant influence on the catalyst; and step C, performing a regression test on two factors including the factor having a significant influence on the catalyst and the ventilation time of the ageing test obtained at step B to obtain a regression equation of the factor having a significant influence on the catalyst and the ventilation time of the ageing test, and determining the failure time of the catalyst according to the regression equation.

In the method for predicting the failure time of a desulfurization catalyst provided by the present invention, a catalyst meeting the standard is screened out through a benchmarking test at first and then an ageing test is performed on the screened catalyst rather than all catalysts, thereby avoiding ineffective work and saving a lot of time. A regression test is performed on two factors including the factor having a significant influence on the catalyst and the ventilation time of the ageing test to obtain a regression equation of the factor having a significant influence on the catalyst and the ventilation time of the ageing test. The failure time of the catalyst is determined according to the regression equation. By substituting the value of the factor having a significant influence on the catalyst into the regression equation, the failure time of the desulfurization catalyst is obtained directly when the value of the factor having a significant influence on the catalyst is changed, instead of performing a test whenever a value is changed, thereby saving time. Moreover, the regression equation obtained from the test results is predictive. The ventilation time of the ageing test here refers to the ventilation time of the sample gas in the ageing test.

In order to improve the accuracy of the regression equation, it is possible to use the simulation results of simulation analysis software to correct the coefficients of the regression equation. Further, the coefficients of the regression equation can be corrected again through an actual test.

A benchmarking test is performed on catalysts of the same volume to determine the desulfurization effects of the catalysts. Firstly, the gas composition of the required natural gas needs to be detected. The detection result of the gas composition, and the gas pressure, gas flow, and other parameters required by the working system are entered into the catalyst volume calculation formula to obtain the catalyst volume. The catalyst volume calculation formula is a commonly used formula in the prior art, so it is not described here.

In a specific embodiment, 4L of a first catalyst can achieve the desulfurization effect. The volume of the first catalyst is 4L and the ratio of inorganic sulfur catalyst to organic sulfur catalyst is 4:1. The volume of a second catalyst is also 4L. The detection systems of the two catalysts are connected in parallel, and the pressure in the pipelines is set at 5 bar through a pressure reducing device. The flow in the pipelines connected in parallel can be regulated to 3,000 mg/s through a float flowmeter. After a certain period of time, the gas thoroughly replaces the gas originally filling the catalyst device. After the flow becomes stable, a gas sample is collected and sent for testing. By checking the sulfides in the sample gases corresponding to the two catalysts, the performances of the two catalysts can be compared and known, and a catalyst of which the detection result of the sulfides in the sample gas meets the standard is selected and further undergoes an ageing test.

The ageing test is an accelerated ageing test under enhanced experimental conditions to simulate the desulfurization effect of the catalyst after hundreds or thousands of hours.

The ageing test is one group or a plurality of groups of three-factor, three-level orthogonal experiments. The enhanced experimental conditions include: increasing the concentration of a substance in the gas, accelerating the poisoning of the catalyst, and raising the working temperature of the catalyst.

Orthogonal experimental design is a design method studying multiple factors and multiple levels. It singles out some representative points through full-scale tests according to orthogonality to perform tests. These representative points have the characteristics of “being evenly dispersed, neat and comparable.” Orthogonal experimental design is a main method of fractional factorial design. It is an efficient, fast, and economical experimental design method. Taking a three-factor and three-level experiment as an example, according to the requirements of the comprehensive experiment, 3 ^L 3=27 combinations of experiments must be performed, without considering the number of repetitions for each combination. If the experiment is arranged according to the L9 (3 ^L 3) orthogonal table, it only needs to be performed 9 times, and if it is arranged according to the LI 8 (3 ^L 7) orthogonal table, it needs to be performed 18 times, obviously significantly reducing the workload. For this reason, orthogonal experimental design has been widely used in many fields of research.

Specifically, increasing the concentration of a substance in the gas increases the concentration of sulfides in the gas. The active component in the catalyst is lost during the reaction process, thereby raising the ageing speed and accelerating poisoning of the catalyst. In order to increase the gas flow rate in the pipeline, strong thermal shock or pressure fluctuations breaks the catalyst particles and the scouring of the reactant fluid pulverizes and blows away the catalyst. Raising the working temperature of the catalyst raises the temperature of the catalyst in the catalyst container or gas temperature. The thermal effect at high temperature enlarges the crystal grains of the active component in the catalyst, resulting in a decrease in the specific surface area, or deterioration of the catalyst.

From the detected desulfurization value obtained from the three-factor, three-level orthogonal experiment, the Gray correlation degree of the three factors is calculated. The Gray correlation degree of the three factors is obtained according to the existing correlation degree calculation procedure or calculation method for three-factor, three-level orthogonal experiments. According to the Gray correlation degree, it is determined that the concentration of sulfides in the gas and the gas flow rate in the pipeline have a significant influence on the sample gas test result.

Table 1 is a test factor level table of a group of three-factor, three-level orthogonal experiments

Table 2 shows the correlation degrees of the correlation degree calculation procedure for a group of three-factor, three-level orthogonal experiments

Selection degree of correlation degree:

The correlation coefficient is:

1 .404048 .333333 1 .772014 .693015 Gray correlation degree:

.579127 .821677

Further, in order to obtain a regression equation, the gas flow rate in the pipeline is increased to the maximum flow value allowed in the system, a regression test is performed on two factors including the concentration of sulfides in the gas and the ventilation time of the ageing test, and eventually, a regression equation of two factors including the concentration of sulfur compounds in the desulfurized sample gas or the concentration of sulfur compounds in the raw gas and the ventilation time of the ageing test is obtained. In a specific embodiment, the gas flow rate in the pipeline is raised to 4500mg/m ³ , the maximum flow allowed in the system, and then a regression test is performed on two factors including the concentration of sulfides in the gas and the ventilation time of the ageing test, and eventually, a regression equation of two factors including the concentration of sulfur compounds in the desulfurized sample gas or the concentration of sulfur compounds in the raw gas and the ventilation time of the ageing test is obtained. In view of the simulation calculation results, by increasing the concentration of sulfur in the feedstock and maintaining the temperature at 40°C, pipeline pressure at 5 bar and flow at 4,500 mg/m ³ , the desulfurization effect of the original natural gas desulfurized for 800 hours can be simulated. After verification of the sample gas, the regression equation is corrected according to the verification result. The equation is corrected again using the actual experimental results in the later stage.

As shown in Fig. 1 to Fig. 4, the present invention further provides a device for predicting the failure time of a desulfurization catalyst. The device comprises a benchmarking test device and an ageing test device. The benchmarking test device comprises a first standard gas cylinder 1. The first standard gas cylinder 1 is in communication with a plurality of sampling and detection lines arranged in parallel through a first pipeline. Each of the sampling and detection lines comprises a first desulfurizer tank 4 and a first sample gas cylinder 5 in communication with each other through a second pipeline. The first desulfurizer tank 4 is arranged adjacent to the first standard gas cylinder 1 and the first desulfurizer tanks 4 on different sampling and detection lines are used for accommodating different catalysts in order to verify the desulfurization effects of various catalysts at the same time. Fig. l is a structural diagram of a benchmarking test device in this embodiment, which tests the desulfurization effects of two catalysts simultaneously. In other words, the benchmarking test device comprises two sampling and detection lines arranged in parallel.

The ageing test device comprises a second standard gas cylinder 6, a second desulfurizer tank 9 and a second sample gas cylinder 10, which are in communication with each other through a third pipeline, and the second desulfurizer tank 9 is used for accommodating a catalyst.

In order to achieve a better catalytic effect, the height-diameter ratio of the first desulfurizer tank 4 and the second desulfurizer tank 9 is 3 : 1. In a specific embodiment, as shown in Fig. 1 and Fig. 2, if the tank body is too high, it will be not suitable for installing the tank body on a vehicle due to the limited space of the vehicle. In order to ensure the doses of the catalysts in the first desulfurizer tank 4 and the second desulfurizer tank 9, two desulfurizer tanks arranged in series are arranged on each sampling line.

In a specific embodiment, a first pressure reducer 2 is arranged on the first pipeline, and a first float flowmeter 3 is arranged on the second pipeline in a position adjacent to the first standard gas cylinder 1. A second pressure reducer 7 and a second float flowmeter 8 are arranged on the third pipeline between the second standard gas cylinder 6 and the second desulfurizer tank 9, and the second pressure reducer 7 is arranged adjacent to the second standard gas cylinder 6. The first pressure reducer 2 and the second pressure reducer 7 facilitate the adjustment of pressures on the corresponding pipelines, and the first float flowmeter 3 and the second float flowmeter 8 facilitate the adjustment of gas flows on the corresponding pipelines.

The first desulfurizer tank 4 and the second desulfurizer tank 9 both comprise a drum body 12 with openings at two ends. An upper end cover 14 with a connection port is connected at an upper opening of the drum body 12, a pipe joint assembly 11 is connected at a lower opening of the drum body 12, and a bed body (not shown in the figure) for accommodating a catalyst is arranged inside the drum body 12. In order to improve the sealing effect of the junction, a sealing gasket 13 is arranged on the junction surface between the upper end cover 14 and the upper end of the drum body 12.

The pipe joint assembly 11 comprises a casing 111. The upper opening of the casing 111 is connected to the drum body 12 in a fixed manner. A first sintered metal mesh 112 and a laser perforated board 113 are arranged inside the casing 111. The first sintered metal mesh 112 is arranged adjacent to the drum body 12, and the lower end of the casing 111 is provided with a connection opening. A second sintered metal mesh (not shown in the figure) is arranged at the upper opening of the drum body 12. Sintered metal meshes are arranged at both the upper end and lower end of the drum body 12 to uniformly disperse the gas flowing therethrough and have an effect of filtering particles. A laser perforated board 113 is arranged under the first sintered metal mesh 112. The laser perforated board 113 is a metal plate with uniformly distributed orifices. When gas enters from a connection opening at the lower end of the casing 111 and meets the laser perforated board 113, the gas disperses to all directions, and enters the cavity between the laser perforated board and the first sintered metal mesh 112 via the orifices. The gas forms turbulence in this cavity so that the gas can more uniformly flow through the desulfurization catalyst bed body along the bottom layer of the tank.

In the description of this solution, the terms indicating directional or positional relations such as “over,” “on,” “above,” “below,” “under,” “vertical,” “upright,” “inside”, and “outside” are based on the directional or positional relations shown in the drawings. They are only for facilitating and simplifying the description of the present invention, and do not indicate or imply that the devices or elements in question must possess specific directions or be constructed and operated in specific directions, so they are limitations to this solution.

Further, the terms “first” and “second” are intended for description only and do not indicate or imply relative importance or implicitly indicate the quantity of the demonstrated technical features. Therefore, the features delimited with “first” or “second” can explicitly or implicitly include one or a plurality of the features. In the description of this solution, unless otherwise specified, “a plurality of’ means two or more than two.

The embodiments in the description are all described in a progressive manner, each embodiment focuses on the differences from other embodiments and the same or similar parts among the embodiments can be mutually referred to.

Various modifications to these embodiments will be apparent. The general principle defined herein can be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention is limited to the embodiments provided herein but should conform to the widest scope consistent with the principles and novel features disclosed.