WO2023124873A1 - Preparation method for and use of catalyst used for efficient catalytic cracking of sludge pyrolysis tar, and real-time measuring system - Google Patents

Abstract

Disclosed in the present invention are a preparation method for and the use of a catalyst used for efficient catalytic cracking of sludge pyrolysis tar, and a real-time measuring system, belonging to the technical fields of preparation of perovskite catalysts and catalysis. In the present invention, twice sol-gel processes are utilized to prepare a catalyst in which a perovskite type oxide is used as a carrier and loaded with a Ni and Co bimetallic oxide on the surface. The inside of the carrier is loaded with metal ions by utilizing the confinement effect of the perovskite type oxide, and oxygen anions in the catalyst react with surface carbon deposit, thus effectively reducing influences, on the catalytic activity of the catalyst, of active metal sintering and covering of active sites with surface carbon deposit of the catalyst, and improving the anti-inactivation capability of the catalyst. The present invention constructs a pyrolysis tar measuring system, with which online measurement of pyrolysis tar generated in any time period is realized, the content information of each component in the pyrolysis tar is accurately analyzed in real time, and substance components and contents in the sludge pyrolysis gasification tar are measured in real time.

Description

Preparation method and application of a catalyst for efficient catalytic cracking of sludge pyrolysis tar and real-time detection system technical field

The invention relates to a preparation method, application and real-time detection system of a catalyst used for efficient catalytic cracking of sludge pyrolysis tar, and belongs to the technical field of preparation and catalysis of perovskite catalysts.

Background technique

Sludge is rich in organic matter. Pyrolysis and gasification can efficiently convert the chemical energy of organic matter into fuel gas, and then co-generate heat and power to generate electricity. It is considered to be an effective way to solve the current problems of sludge treatment and safe disposal. However, impurities such as tar and its intermediate products, solid particles, and nitrogen sulfides will be produced during the pyrolysis of sludge, and the tar content accounts for more than 80% of the total amount of impurities. The existence of tar pollutes the environment, blocks pipelines, corrodes equipment, reduces the energy conversion rate of biomass gasification, and endangers human health. Therefore, the removal of tar in fuel gas is a long-term problem in the development of sludge pyrolysis gasification technology.

Among various tar treatment methods, the catalytic cracking method can reduce the reaction activation energy under the action of a suitable catalyst, so that the conversion temperature of the tar can be greatly reduced, and at the same time, the catalytic reformation of the tar into a small molecule fuel gas is a kind of tar with great development potential. in situ removal technique.

However, the existing tar in-situ catalytic cracking technology mainly has two problems in the actual engineering application process: one is the lack of high-efficiency catalysts with strong catalytic ability and good anti-pollution performance, and the other is the lack of catalysts and tar in the catalytic pyrolysis process. On-line real-time detection method of secondary products. At present, it is known that nickel-based catalysts have good catalytic cracking efficiency of tar, but in the application process, it is found that the catalytic sites on the metal surface are easily reduced due to carbon deposition and grain agglomeration of nickel metal, which deactivates the nickel metal and leads to catalytic degradation. Efficiency drops dramatically. Therefore, it is very necessary to provide a catalyst that can improve the activity of the catalyst and limit the sintering and carbon deposition of the catalytic metal grains.

At the same time, since tar pyrolysis catalysts still have the disadvantage of catalyst deactivation, in order to better characterize the performance of catalysts in the process of tar catalytic pyrolysis, it is necessary to solve the problem of real-time detection of tar components and concentrations, and provide a basis for catalyst regeneration and regular replacement. Supported by data, it can also ensure the stable quality of gas products obtained by pyrolysis and gasification. At present, the tar detection technology is mainly to conduct off-line analysis of the collected pyrolysis tar tail gas on laboratory testing instruments. Although this method can obtain the composition and content of tar pyrolysis gasification products, the cost of manpower and material resources is relatively high. And it takes a long time, and it is impossible to get real-time gasification product data, so it is difficult to promote to large-scale engineering applications. Therefore, it is also necessary to provide a real-time detection system for tar products to provide data support for catalyst regeneration and periodic replacement.

Contents of the invention

In order to solve the problems existing in the above-mentioned prior art, the present invention provides a high-efficiency sludge pyrolysis tar catalytic cracking catalyst with high tar catalytic efficiency, strong anti-deactivation ability, catalyst preparation method and stable and controllable performance, and constructs a A real-time detection system capable of quantitatively analyzing the components and contents of sludge catalytic pyrolysis tar.

Technical scheme of the present invention:

A method for preparing a catalyst for efficient catalytic cracking of sludge pyrolysis tar, the method comprising the following steps:

Step 1, using a sol-gel method to prepare a perovskite-type oxide carrier;

In step 2, a nickel-cobalt binary metal is supported on a perovskite oxide carrier by using a sol-gel method to obtain a catalyst for efficient catalytic cracking of sludge pyrolysis tar.

To further define, the operation process of step 1 is as follows:

After mixing lanthanum nitrate, strontium nitrate and aluminum nitrate evenly, adding citric acid and ethylene glycol to form a perovskite oxide precursor, drying, grinding, and then calcining to form a perovskite oxide carrier.

Further defined, the mass ratio of lanthanum nitrate, strontium nitrate and aluminum nitrate in step 1 is (8.08-10.39):(0.57-1.69):10.

Further defined, the ratio of the total molar weight of lanthanum nitrate, strontium nitrate and aluminum nitrate to the molar weight of citric acid and the molar weight of ethylene glycol in step 1 is 1:2:(1-3).

Further defined, the drying treatment conditions in step 1 are: temperature 85°C, time 12h.

Further defined, the calcination treatment conditions in step 1 are: temperature 900°C, time 4h.

To further define, the operation process of step 2 is as follows:

After uniformly mixing the perovskite oxide carrier, nickel nitrate and cobalt nitrate prepared in step 1, adding citric acid and ethylene glycol to form a perovskite oxide precursor, drying, grinding, and then calcining to form a catalyst.

Further defined, the mass ratio of nickel nitrate, cobalt nitrate and perovskite oxide precursor in step 2 is (3.16-6.33):(1.09-3.29):10.

Further defined, the ratio of the total molar weight of nickel nitrate, cobalt nitrate and perovskite oxide precursor to the molar weight of citric acid and the molar weight of ethylene glycol is 1:2:(1-3).

Further defined, the drying treatment conditions in step 2 are as follows: a temperature of 85° C. and a time of 12 hours.

Further defined, the calcination treatment conditions in step 2 are as follows: a temperature of 900° C. and a time of 4 to 6 hours.

The above-mentioned catalyst is used in the method for high-efficiency catalytic cracking of sludge pyrolysis tar, comprising the following steps:

Step 1, mixing sludge pyrolysis tar and perovskite-type oxide catalyst at 700°C to 800°C for catalytic cracking reaction to generate pyrolysis tar;

In step 2, the pyrolysis tar generated in step 1 is passed into a real-time pyrolysis tar detection system to detect and analyze the components and contents of the pyrolysis tar in real time.

To further define, the specific operation process of Step 1 is:

The sludge pyrolysis tar is added to the upper pipe section of the two-stage fixed-bed reactor, the perovskite oxide catalyst is added to the lower pipe section, and then the temperature of the lower pipe section is raised to 700°C at a heating rate of 30°C/min, and then Feed H ₂ into the system at a flow rate of 100mL/min, stop feeding H ₂ after 30min, feed N ₂ into the system at a flow rate of 500mL/min, continue 5min, and finally switch the feeding rate of N ₂ to 100mL/min, and control the upper pipe section to raise the temperature to 300°C at a rate of 30°C/min to gasify the sludge tar and carry out catalytic cracking reaction to generate cracked gas.

It is further defined that the pyrolysis tar real-time detection system in step 2 includes a smoke filter, a dryer, a gas holding tank, a GC-MS detection system, a pyrolysis tar condensation system and a gas collection system, and the pyrolysis tar produced by a two-stage fixed-bed reactor After the gas is sequentially treated by the soot filter, dryer and gas insulation tank, part of it enters the GC-MS detection system through valve control, and the other part passes through the pyrolysis tar condensation system and is collected by the gas collection system.

It is further defined that the GC-MS detection system includes an online gas chromatography-mass spectrometry system and a computer digital display system, and the line gas chromatography-mass spectrometry system includes a gas source system for generating H _and He, a gas chromatography and mass spectrometry detector and Sample collection aspirator.

To further define, the soot filter adopts ceramic membrane physical filtration.

Further defined, the gas drying pool is a U-shaped tube in which calcium chloride or color-changing silica gel is placed.

It is further defined that the function of the gas holding tank is to keep the pyrolysis tar warm, so that the pyrolysis tar is maintained at a temperature not lower than 300°C (maintained at 300-400°C).

Further defined, the pyrolysis tar condensation system consists of two stages of ice-water bath n-hexane solvent connected in series.

Further defined, the gas collection system includes a gas flow monitor and an air bag, and the gas flow detector is used to measure the real-time flow of pyrolysis tar and calculate the accumulated flow.

Beneficial effects of the present invention:

(1) The present invention adopts two sol-gel methods to prepare the catalyst of Ni and Co double metal oxides loaded on the surface of the carrier with the perovskite oxide, and utilizes the confinement effect of the perovskite oxide to make the metal ion load Inside the carrier, at the same time, the oxygen negative ions inside the catalyst react with the carbon on the surface, which can effectively reduce the influence of the sintering of the active metal of the catalyst and the coverage of active sites by carbon on the surface of the catalyst on the catalytic activity of the catalyst, and improve the anti-deactivation ability of the catalyst.

(2) The present invention utilizes the properties of perovskite-type oxide mixed ion-electron conductors to conduct oxygen anions and electrons at the same time, greatly increasing the number of catalytic active sites and reaction interfaces, and effectively improving the catalytic activity and product resistance of the catalyst. The carbon capacity has high catalytic cracking performance for tar, and the conversion rate of tar can reach more than 80%. After the reaction, the types of substances in the pyrolysis gas of sludge tar are reduced, and the content of small molecular compounds is increased, which effectively improves the quality of pyrolysis gas of sludge tar. In addition, the synergistic effect of Ni-Co bimetal can also improve the catalytic activity and service life of the catalyst.

(3) The catalyst activation process provided by the present invention is to reduce the Ni and Co double metal oxides supported on the surface of the perovskite carrier to a simple form under the action of a high-temperature H ₂ /N ₂ atmosphere, which is composed of La, Sr, and Al The perovskite oxide support can maintain a stable structure under this condition without destroying the structure of the original perovskite oxide, and the catalytic active component is mainly the reduced Ni-Co bimetal.

(4) The present invention adopts the sol-gel method to prepare the perovskite precursor, the sol-gel method is relatively simple, and the cost is low, while the synthesized oxide has a stable crystal structure, good lattice oxygen activity, high The specific surface area of the catalyst, and a certain proportion of ethylene glycol is added during the preparation process to promote the formation of a uniform and stable gel during the preparation process, while reducing the severity of the decomposition process of the gel during the calcination process, which can prevent the thermal expansion of the citric acid gel Material waste from overflow reaction carrier. At the same time, evaporate and dry at 85°C, the precursor solution is first concentrated into a uniform wet gel and then dried into a foamy solid, and a perovskite oxide precursor with less impurities and stable components can be obtained. After calcination, La _x Sr _1-x AlO ₃ stable perovskite oxide carrier, Sr is a commonly used perovskite A-site dopant, which can make the perovskite carrier obtain more active sites and lattice oxygen, improve catalytic activity and anti- Carbon deposition performance.

(5) The present invention uses the sol-gel method to load Ni and Co bimetals on the La _x Sr _1-x AlO ₃ perovskite oxide carrier, and the synergistic effect of Ni-Co bimetals can effectively improve the catalytic activity of metals at high temperatures. Ability to resist sintering. Compared with the impregnation method, the sol-gel method can make the combination of the metal and the support more tightly. Under the action of sol-gel method, Ni ²⁺ and Co ²⁺ can be combined with excess A-site metal La ³⁺ or Sr ²⁺ in the perovskite oxide support and introduced into the perovskite structure, which can further improve the catalyst active sites and lattice oxygen content; in addition, this process also leads to the La and Sr element content on the surface of the catalyst is higher than that of the impregnation method, the Sr element provides an alkaline environment for the catalyst, and inhibits the Carbon deposition on the surface of the catalyst improves the anti-coking ability of the catalyst.

(6) In order to better characterize the effectiveness of the catalyst in the tar catalytic pyrolysis process, the present invention builds a pyrolysis tar real-time detection system, which can realize real-time detection of the pyrolysis tar and content produced at any time period, from The pyrolysis tar produced by the two-stage fixed-bed reactor first passes through the soot filter and the gas dryer to remove the solid particles and water vapor of the pyrolysis tar, so as to reduce the interference of impurities in the pyrolysis tar to the detection system, and clean and dry the pyrolysis tar in the Under the action of the air pump, it enters the gas chromatography-mass spectrometry detection system for qualitative and quantitative analysis, realizing real-time and accurate analysis of the content information of various components in the pyrolysis tar, such as benzene, toluene, xylene, naphthalene, oleic acid amide, etc. Concentration, real-time detection of material composition and content in sludge pyrolysis gasification tar.

Description of drawings

Figure 1 is a schematic diagram of a sludge pyrolysis reaction platform and a real-time detection device for tar products.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in this field unless otherwise specified, and those skilled in the art can obtain them through commercial channels.

Example 1:

The preparation method of catalyst is:

(1) Put 3.464g of lanthanum nitrate, 0.4233g of strontium nitrate and 3.751g of aluminum nitrate into a beaker, mix and dissolve them in deionized water, add 8.406g of citric acid and 3.34mL of ethylene glycol into the system and stir until completely dissolved, and add Put a rotor inside and stir for 12 hours under the action of a magnetic stirrer, and then dry in an oven at 85° C. for 12 hours to obtain a perovskite oxide precursor. The precursor was ground and placed in a quartz boat, and calcined at 900°C for 4 hours to obtain the perovskite oxide carrier powder.

(2) Dissolve 0.7907g nickel nitrate and 0.3288g cobalt nitrate in water, then add 1.618g citric acid and stir until completely dissolved, then add 1.5g of perovskite oxide carrier powder prepared in step 1 to the system, Put a rotor inside and stir for 12 hours under the action of a magnetic stirrer, and then dry in an oven at 85° C. for 12 hours to obtain a novel catalyst precursor. The precursor was ground and placed in a quartz boat, and calcined at 800°C for 4 hours to obtain the new catalyst powder. Grind the new catalyst powder to 60-100 mesh for later use.

The prepared catalyst is used in the high-efficiency catalytic cracking of sludge pyrolysis tar. The specific experimental device is shown in Figure 1, including a two-stage fixed-bed reactor 1, a temperature control device 2, a gas supply system 3, and standard substance injection Port 4, two-stage reaction heating furnace 5, smoke filter 7, gas dryer 8, gas holding tank 9, sampling valve 10, online gas chromatography-mass spectrometry detection system 11, carrier gas system 12, air pump 13, computer 14 , condensation and absorption system 15, gas flow meter 16 and gas collection bag 17, wherein the furnace material of the two-stage fixed bed reactor 1 is polycrystalline alumina refractory material, the maximum temperature can reach 1200 ° C, and the specification for placing in the heating furnace is The two-stage _quartz tube with a total length of 750mm and a diameter of 30mm can withstand high temperature of 1200°C. The gas supply system 3 is composed of _N2 gas cylinder, hydrogen generator, gas flow rate controller and gas passage. The volume purity of _N2 is above 99.9%, the _H2 production rate of the hydrogen generator is up to 500mL/min, the volume purity of _H2 is above 99.9%, the gas flow rate controller controls the gas flow rate to change from 0 to 500mL/min, and the smoke filter is 7 Mainly use the method of ceramic membrane physical filtration, the gas dryer 8 is a U-shaped tube for placing calcium chloride or color-changing silica gel, and the function of the gas holding tank 9 is to keep the pyrolysis tar at a temperature of not less than 300 At a temperature of ℃ (maintained at 300-400 ℃), the condensation and absorption system 15 is composed of two-stage ice-water bath n-hexane, and the gas flowmeter 16 can measure the real-time flow of non-condensable gas and calculate the cumulative flow, and the final non-condensable gas passes through the gas The collection bag 17 is collected for use.

During work, the sludge tar and the catalyst are respectively placed on the quartz sand gasket 6 of the upper section of the quartz fixed bed reactor 1 and on the quartz sand gasket 6 of the lower section, and the temperature control device 2 and the gas supply system 3 are adjusted, and the reserved The standard substance inlet 4 of the standard substance is closed, the carrier gas system 12 of gas chromatography-mass spectrometry is opened, and the two-stage reaction heating furnace 5 is opened, and the sludge tar is heated and gasified on the two-stage pyrolysis reaction platform, and passed through the lower section of quartz sand The catalyst on the gasket 6 catalyzes cracking to generate pyrolysis tar. The sample gas passes through the soot filter 7 to filter solid particles, and then passes through the gas dryer 8 to remove water vapor. The temperature of the pyrolysis tar is kept at 300°C through the gas holding tank 9. Then open the gas chromatography-mass spectrometry gas detection sampling valve 10, air pump 13, part of the gas sample enters the online gas chromatography-mass spectrometry detection system 11, and the pyrolysis tar is separated by the chromatographic column in the gas chromatography-mass spectrometry detection system 11 and produces different intensities kurtosis signal, and the gas composition information is obtained in the mass spectrum, and the real-time composition and content data of the pyrolysis tar are displayed in the computer 14 . The remaining pyrolysis tar passes through a two-stage ice-water bath n-hexane absorption system 15 to collect tar components therein, and the gas flow meter 16 and gas collection bag 17 store the non-condensable gas in the pyrolysis tar.

Method for real-time detection of pyrolysis tar by detection system:

Firstly, the components of the pyrolysis tar were analyzed to obtain the substances with relatively high content in the tar, including benzene, toluene, xylene, naphthalene, oleic acid amide and other substances, as well as the mass fraction of the above-mentioned substances in the tar, and stored in a computer system.

Then, the pyrolysis tar is input into the sludge pyrolysis system, and the material composition in the tar is judged according to the mass spectrum. The concentration of the corresponding compound is obtained by comparing the peak area of the standard substance, and the concentration of the tar gas is determined by the concentration of the calibrated compound.

In this embodiment, toluene gas is taken as an example for illustration. Standard toluene gas samples with different concentrations enter the detection system through the reactor, and the corresponding characteristic spectral lines are output. The peak area of each group of toluene standard substances corresponds to the concentration of toluene to produce toluene standard curve function. The toluene standard peak area and the corresponding toluene concentration data are shown in Table 1 below;

Concentration of toluene (volume percent %)	The peak area corresponding to the characteristic line
0.2	6.70735
0.4	15.36752
0.8	29.02832
2	73.1144
4	135.02573

According to the data in Table 1, the function of the concentration x of toluene and the corresponding standard peak area y of toluene obtained through data fitting is y=33.714x+1.9521.

Then, the gas to be detected is input into the detection system, and by comparing the retention time of the standard characteristic line of the above-mentioned characteristic line and toluene, there is a spectral peak identical with the retention time of the standard characteristic line of toluene in the above-mentioned characteristic line, so it can be Make sure that the gas to be detected contains toluene. According to the peak area of the characteristic spectral line, the concentration of toluene is determined by the toluene standard curve function.

It is 0.510% (volume fraction) to verify the above-mentioned detection method with the gas to be detected that contains the actual concentration of toluene, when the gas to be detected is input in the detection system, can obtain a group of peak area and be the characteristic line of toluene of 18.74167, according to the concentration of toluene The function of x and the corresponding peak area y of the standard characteristic line of toluene is y=33.714x+1.9521, and the obtained toluene concentration is 0.498%. It can be seen that according to the method in the embodiment of the present invention, the relative error is 2.4%

The above method is verified by the gas to be detected with an actual concentration of 1.020% toluene. When the gas to be detected is input into the detection system, a group of characteristic lines of toluene with a peak area of 35.02553 can be obtained. According to the concentration x of toluene and the corresponding toluene The function of the peak area y of the standard characteristic line is y=33.714x+1.9521, and the concentration of toluene obtained is 0.981%. It can be seen that according to the method in the embodiment of the present invention, the relative error is 4.0%.

The above detection method is verified by the gas to be detected with an actual concentration of 2.040% toluene. When the gas to be detected is input into the detection system, a group of characteristic lines of toluene with a peak area of 73.42578 can be obtained. According to the concentration x of toluene and the corresponding The function of the peak area y of the standard characteristic line of toluene is y=33.714x+1.9521, and the concentration of the obtained toluene is 2.120%. It can be seen that according to the method in the embodiment of the present invention, the relative error is 3.7%.

From the above results, it can be seen that the error between the toluene concentration measured according to the detection method provided by the embodiment of the present invention and the toluene concentration in the gas to be detected is less than 5%, and the measurement result is relatively accurate.

In this example, the pyrolysis tar sample was taken before catalytic cracking, and the composition of the sludge pyrolysis tar was analyzed by GC/MS. The concentration of toluene in the pyrolysis tar was compared with the total mass of tar produced before and after the catalytic reaction, and the sludge pyrolysis tar was obtained. The mass fraction of toluene in the medium is 15%.

The working process of the present embodiment catalytic pyrolysis reaction is as follows:

Add 0.8g of sludge pyrolysis tar to the upper pipe section of the two-stage fixed-bed reactor 1, add 0.8g of perovskite-type oxide catalyst to the lower pipe section, and start the two-stage reaction heating furnace 5 at a heating rate of 30°C/min Raise the temperature of the lower pipe section to 700°C to gasify the sludge tar on the quartz sand gasket 6, control the temperature rise rate of the upper pipe section to 300°C at a rate of 30°C/min, and then adjust the gas flow rate controller 3 to 100mL/min Feed H ₂ into the system at a flow rate of 30 minutes, stop feeding H ₂ , start feeding N ₂ into the system at a flow rate of 500 mL/min for 5 min, and switch the N ₂ feeding rate to 100 mL/min. Concentration of 3.250% (volume fraction) toluene is added into the system through the toluene feed port, and after the toluene is gasified in the upper pipe section, it enters the lower pipe section containing the catalyst with the carrier gas, and the sludge tar catalytic pyrolysis reaction starts.

Open the sampling valve 10, open the air pump 13, the pyrolysis tar enters the tar real-time detection device, outputs the characteristic spectrum line of toluene in the pyrolysis tar at the computer end to calculate the toluene concentration, and obtains the concentration data of toluene to be 0.423vol%, shows that the reaction system is right The removal rate of toluene is as high as 87%. Finally, it is known that the content of toluene in pyrolysis tar accounts for about 15% of the tar, so the concentration of tar in the gas to be detected can be obtained by dividing the measured toluene content by 0.15.

The above description is only a preferred embodiment of the present invention, in view of those skilled in the art of the present invention can make appropriate changes and modifications to the above implementation, therefore, the present invention is not limited to the specific implementation described above, Some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.

Claims (10)

1. A method for preparing a catalyst for efficient catalytic cracking of sludge pyrolysis tar, characterized in that the method comprises the following steps:

   Step 1, using a sol-gel method to prepare a perovskite-type oxide carrier;

   In step 2, a nickel-cobalt binary metal is supported on a perovskite oxide carrier by using a sol-gel method to obtain a catalyst for efficient catalytic cracking of sludge pyrolysis tar.
2. A kind of preparation method for the catalyst of sludge pyrolysis tar efficient catalytic cracking according to claim 1, it is characterized in that, the operation process of described step 1 is as follows:

   After mixing lanthanum nitrate, strontium nitrate and aluminum nitrate evenly, adding citric acid and ethylene glycol to form a perovskite oxide precursor, drying, grinding, and then calcining to form a perovskite oxide carrier.
3. A kind of preparation method for the catalyst of sludge pyrolysis tar efficient catalytic cracking according to claim 2, it is characterized in that, in described step 1, the mass ratio of lanthanum nitrate, strontium nitrate and aluminum nitrate is (8.08～ 10.39): (0.57～1.69): 10; the ratio of the total molar weight of lanthanum nitrate, strontium nitrate and aluminum nitrate to the molar weight of citric acid and the molar weight of ethylene glycol in the step 1 is 1:2:( 1~3).
4. A method for preparing a catalyst for efficient catalytic cracking of sludge pyrolysis tar according to claim 2, wherein the drying treatment conditions in the step 1 are: temperature 85°C, time 12h; The calcination treatment conditions in step 1 are: temperature 900°C, time 4h.
5. A kind of preparation method for the catalyst of sludge pyrolysis tar efficient catalytic cracking according to claim 1, it is characterized in that, the operation process of described step 2 is as follows:

   After uniformly mixing the perovskite oxide carrier, nickel nitrate and cobalt nitrate prepared in step 1, adding citric acid and ethylene glycol to form a perovskite oxide precursor, drying, grinding, and then calcining to form a catalyst.
6. A kind of preparation method for the catalyst of sludge pyrolysis tar efficient catalytic cracking according to claim 5, it is characterized in that, in described step 2, nickel nitrate, cobalt nitrate and perovskite type oxide precursor The mass ratio is (3.16-6.33): (1.09-3.29): 10; the total molar weight of nickel nitrate, cobalt nitrate and perovskite-type oxide precursor, the molar weight of citric acid and the molar weight of ethylene glycol The ratio of quantity is 1:2:(1～3).
7. A method for preparing a catalyst for efficient catalytic cracking of sludge pyrolysis tar according to claim 5, wherein the drying treatment conditions in the step 2 are: temperature 85°C, time 12h; The calcination treatment conditions in the step 2 are as follows: the temperature is 900° C., and the time is 4-6 hours.
8. A method for the high-efficiency catalytic cracking of sludge pyrolysis tar, wherein the catalyst according to claim 1 is characterized in that the method comprises the following steps:

   Step 1, mixing sludge pyrolysis tar and perovskite-type oxide catalyst at 700°C to 800°C for catalytic cracking reaction to generate cracked gas;

   In step two, the pyrolysis gas generated in step one is fed into the pyrolysis tar real-time detection system, and the components and contents of the pyrolysis tar are detected and analyzed in real time.
9. The catalyst according to claim 8 is used for the method of efficient catalytic cracking of sludge pyrolysis tar, characterized in that, the specific operation process of the described step 1 is:

   The sludge pyrolysis tar is added to the upper pipe section of the two-stage fixed-bed reactor, the perovskite oxide catalyst is added to the lower pipe section, and then the temperature of the lower pipe section is raised to 700°C at a heating rate of 30°C/min, and then Feed H ₂ into the system at a flow rate of 100mL/min, stop feeding H ₂ after 30min, feed N ₂ into the system at a flow rate of 500mL/min, continue 5min, and finally switch the feeding rate of N ₂ to 100mL/min, and control the upper pipe section to raise the temperature to 300°C at a rate of 30°C/min to gasify the sludge tar and carry out catalytic cracking reaction to generate cracked gas.
10. The catalyst according to claim 8 is used for the method of high-efficiency catalytic cracking of sludge pyrolysis tar, it is characterized in that, the pyrolysis tar real-time detection system of described step 2 comprises soot filter, drier, gas holding tank, GC -MS detection system, pyrolysis tar condensation system and gas collection system, the pyrolysis gas generated by the two-stage fixed bed reactor is sequentially processed through the soot filter, dryer and gas holding tank, and part of it enters the GC-MS through valve control The detection system, and the other part is collected through the gas collection system after passing through the pyrolysis tar condensation system.

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