Method and device for preparing light fuel oil by staged catalytic pyrolysis of oil-containing sludge

Abstract

The present application relates to solid waste resource utilization technical field, particularly to a kind of method and device for preparing light fuel oil by sectioned catalytic pyrolysis of oily sludge.The method comprises the following steps: oily sludge is sent into low-temperature pyrolysis section in sectioned pyrolysis reactor, and pyrolysis is carried out at 300-450 DEG C, to generate primary pyrolysis oil gas and semi-coke;primary pyrolysis oil gas flows into high-temperature catalytic reforming section in reactor, and contact with calcium-based catalytic material loaded in the section at 450-600 DEG C, to generate oil gas mixture by catalytic reforming reaction;oil gas mixture is led out from reactor outlet, and light fuel oil is obtained after condensation separation;at the same time, catalytic material is discharged, and recycled after regeneration treatment.The present application realizes the improvement of light fuel oil quality, the reduction of system energy consumption and the recycling of catalyst by integrating low-temperature pyrolysis and high-temperature catalytic reforming in the same reactor, and cooperating with in-situ regeneration cycle of calcium-based catalytic material.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a method and apparatus for preparing light fuel oil by staged catalytic pyrolysis of oily sludge. Background Technology

[0002] Oily sludge, primarily generated during oil extraction, transportation, and refining, is a complex hazardous waste. It typically contains heavy oil components, gums, asphaltenes, and solid impurities, possessing both resource recovery value and environmental pollution risks. Pyrolysis technology, as a treatment method capable of reducing volume, rendering harmless, and recycling resources, has received widespread attention in the field of oily sludge treatment.

[0003] Currently, conventional single-stage pyrolysis processes still face several technical limitations in practical applications. First, the quality of the pyrolysis-derived oil is relatively poor, with products consisting mostly of heavy components containing significant amounts of olefins and oxygen-containing compounds. This results in insufficient stability, high acid values, and low calorific values, making direct use as fuel or chemical feedstock difficult. Second, a single temperature condition cannot simultaneously achieve effective volatilization of light components and complete cracking of heavy components, limiting the yield of light oil products such as gasoline and diesel fractions. Furthermore, when attempting to introduce catalysts to improve oil quality, the catalysts are prone to deactivation due to carbon buildup, sintering, or reactions with impurities in the sludge. Separating the catalyst from the pyrolysis residue is also difficult, leading to high recycling costs and hindering catalyst recycling. Some improved processes employ a two-stage design, placing the pyrolysis and catalytic reforming processes in separate reactors. This results in a more complex system structure and a corresponding increase in energy consumption.

[0004] Therefore, developing a process that can achieve deep coupling of pyrolysis and catalysis in an integrated system, improve the quality of light oil products, and has the ability to regenerate and recycle catalysts in situ is of positive significance for the resource utilization of oily sludge. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a method and apparatus for preparing light fuel oil through segmented catalytic pyrolysis of oily sludge. By integrating low-temperature pyrolysis and high-temperature catalytic reforming in the same reactor, and cooperating with in-situ regeneration and recycling of calcium-based catalytic materials, the quality of light fuel oil is improved, system energy consumption is reduced, and catalysts are recycled.

[0006] To achieve the above objectives, the present invention provides a method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge, comprising the following steps: S1. The pretreated oily sludge is fed into the low-temperature pyrolysis section of the segmented pyrolysis reactor and pyrolyzed at 300-450℃ to generate primary pyrolysis oil and gas and semi-coke. S2. Primary pyrolysis oil and gas flow from the low-temperature pyrolysis section into the high-temperature catalytic reforming section set in the segmented pyrolysis reactor. The high-temperature catalytic reforming section is physically connected to the low-temperature pyrolysis section and the temperature is independently controlled. The primary pyrolysis oil and gas comes into contact with the calcium-based catalytic material packed in this section at 450-600℃, and a catalytic reforming reaction occurs to generate an oil and gas mixture. S3. The oil-gas mixture is drawn out from the outlet of the segmented pyrolysis reactor, and after condensation and separation, light fuel oil is obtained; at the same time, the calcium-based catalyst material of the high-temperature catalytic reforming section is discharged, regenerated, and returned to the high-temperature catalytic reforming section for recycling.

[0007] In an optional embodiment, the pretreatment in S1 includes: dewatering, crushing and screening the oily sludge to control its moisture content to be less than 10 wt% and its particle size to be less than 10 mm.

[0008] In an optional embodiment, in S1, pyrolysis is carried out under an inert atmosphere or oxygen-deficient conditions. Light oils in the oily sludge volatilize, while heavy colloids and asphaltenes undergo preliminary cracking, generating primary pyrolysis oil and gas containing medium- and long-chain alkanes, olefins, and oxygen-containing compounds. Simultaneously, pyrolysis semi-coke rich in fixed carbon is produced. The semi-coke is discharged from the end of the low-temperature pyrolysis section and can be used as solid fuel or an adsorbent.

[0009] In an optional embodiment, in S2, the primary pyrolysis oil and gas enter the high-temperature catalytic reforming section under the carrying of a carrier gas, wherein the carrier gas is selected from at least one of nitrogen and water vapor.

[0010] In an optional embodiment, in S2, the calcium-based catalytic material is a supported catalyst; the active component of the calcium-based catalytic material is selected from CaO, and the support is selected from at least one of hydroxyapatite and acid-treated sepiolite.

[0011] In an optional embodiment, the method for preparing acid-treated sepiolite includes the following steps: placing sepiolite in an acid solution, stirring under heating conditions, then filtering, washing until neutral, drying, and calcining to obtain acid-treated sepiolite.

[0012] In one alternative embodiment, the support accounts for 20-50% of the total mass of the calcium-based catalytic material.

[0013] In an optional embodiment, in S2, the high-temperature catalytic reforming section contains a CO2 atmosphere, under which the calcium-based catalytic material forms CaO-CaCO3 composite active centers. Specifically, under a high-temperature CO2 atmosphere, the surface of the active component CaO in the calcium-based composite catalytic material is partially converted into CaCO3, forming CaO-CaCO3 composite active centers. This composite system utilizes the basic sites of CaO to catalyze the deoxygenation reaction of oxygen-containing compounds (such as carboxylic acids and phenols); on the other hand, the catalyst support provides acidic sites, promoting the cyclization and aromatization of olefins and the selective cracking of long-chain alkanes, and saturating some double bonds through hydrogen transfer reactions on the catalyst surface, thereby increasing the proportion of high-quality components such as isoalkanes and monocyclic aromatics in the products. Simultaneously, the CaO-CaCO3 system continuously adsorbs acidic gases such as CO2 and H2S from the pyrolysis gas through a dynamic cycle of carbonation-decomposition, protecting the equipment and subsequent processes.

[0014] In an optional implementation, in S1, the pyrolysis time of the low-temperature pyrolysis section is 25-35 min.

[0015] In an optional embodiment, in S2, the catalytic reforming reaction takes 2-10 seconds.

[0016] In an optional embodiment, in step S3, the high-temperature oil-gas mixture after catalytic reforming leaves the staged pyrolysis reactor and enters a condensation system for rapid cooling to below room temperature, achieving gas-liquid separation. After oil-water separation, the liquid phase yields high-quality light fuel oil (mainly composed of C5-C). 20 The system contains alkanes, cycloalkanes, and aromatics, as well as reaction water; non-condensable gases (mainly H2, etc.) can be collected after purification and used as a system heat source or for other purposes.

[0017] In an optional embodiment, in S3, the regeneration process includes calcining the discharged calcium-based catalyst material at 600-800°C in an oxygen-containing atmosphere. Specifically, during the reaction, calcium-based catalyst material whose activity decreases due to carbon buildup or impurity adsorption is periodically discharged from the discharge valve of the high-temperature catalytic reforming section. The discharged deactivated catalyst material is then transported to the catalyst material regeneration module and calcined at 600-800°C in an oxygen-containing atmosphere to burn off the surface carbon and decompose CaCO3 to regenerate CaO, restoring its pore structure and catalytic activity. The regenerated catalyst material is then returned to the high-temperature catalytic reforming section for recycling after being replenished with fresh catalyst material.

[0018] The present invention also provides an apparatus for the staged catalytic pyrolysis of oily sludge to prepare light fuel oil for implementing the method, comprising: The segmented pyrolysis reactor has a low-temperature pyrolysis section and a high-temperature catalytic reforming section arranged sequentially along the material movement direction inside, with a temperature isolation zone between the two sections. The high-temperature catalytic reforming section is filled with calcium-based catalytic material. The feeding module is connected to the inlet of the low-temperature pyrolysis section and is used to transport the pretreated oily sludge to the low-temperature pyrolysis section. The catalytic material regeneration module is connected to the high-temperature catalytic reforming section and is used to receive the calcium-based catalytic material discharged from the section and regenerate it, and then return the regenerated calcium-based catalytic material to the high-temperature catalytic reforming section. An oil-gas separation and collection module is connected to the oil-gas outlet of the segmented pyrolysis reactor and is used to condense and separate the oil-gas mixture drawn from the outlet.

[0019] In one optional embodiment, the segmented pyrolysis reactor is a horizontal or slightly inclined rotary kiln or multi-stage furnace with an independent heating and control system; a throttling or gas-sealing device to prevent gas back-mixing is provided between the low-temperature pyrolysis section and the high-temperature catalytic reforming section.

[0020] In an optional embodiment, a controllable catalytic material discharge valve is provided at the bottom end of the high-temperature catalytic reforming section, and the discharge valve is connected to the inlet of the catalytic material regeneration module.

[0021] In an optional embodiment, the high-temperature catalytic reforming section is further provided with a catalytic material feeding port, which is connected to the outlet of the catalytic material regeneration module.

[0022] The beneficial effects of this invention are as follows: (1) This invention sets up a low-temperature pyrolysis section and a high-temperature catalytic reforming section in the same reactor, forming a stepped conversion mode of "low-temperature primary cracking + high-temperature catalytic reforming". In the high-temperature catalytic reforming section, calcium-based catalysts form CaO-CaCO3 composite active centers under a CO2 atmosphere. This composite system plays multiple synergistic roles: the basic sites of CaO catalyze the deoxygenation reaction of oxygen-containing compounds, effectively reducing the oxygen content and acid value of the pyrolysis oil; the acidic sites provided by the support promote the cyclization and aromatization of olefins and the selective cracking of long-chain alkanes, and significantly increase the proportion of high-quality components such as isoalkanes and monocyclic aromatics in the product through hydrogen transfer reaction on the catalyst surface. At the same time, the CaO-CaCO3 system continuously adsorbs acidic gases such as CO2 and H2S in the pyrolysis gas through a dynamic cycle of carbonation-decomposition, playing a role in protecting the equipment and subsequent processes.

[0023] (2) In this invention, the low-temperature pyrolysis section and the high-temperature catalytic reforming section are set in the same segmented pyrolysis reactor, and the two sections are physically connected and their temperatures are independently controlled. The primary pyrolysis oil and gas are generated in the low-temperature pyrolysis section and flow directly into the high-temperature catalytic reforming section without intermediate heating and cooling links, realizing efficient cascade utilization of system heat and avoiding repeated heating and heat loss caused by the use of independent reactors in traditional two-stage processes.

[0024] (3) This invention, by setting up a catalytic material regeneration module, periodically discharges the calcium-based catalytic material whose activity has decreased due to carbon deposition or impurity adsorption in the high-temperature catalytic reforming stage, and returns it for recycling after calcination regeneration. This design effectively solves the problems of difficult separation of catalyst and pyrolysis residue and high recycling costs in the prior art. After multiple regeneration cycles, the catalytic material can still maintain good catalytic activity and product selectivity, which can meet the requirements of continuous industrial production and significantly reduce catalyst replacement costs and system operating costs.

[0025] (4) In the device provided by the present invention, a catalytic material discharge valve that can be controlled to open and close is provided at the bottom end of the high-temperature catalytic reforming section. The discharge valve is connected to the inlet of the catalytic material regeneration module. The high-temperature catalytic reforming section is also provided with a catalytic material feeding port, which is connected to the outlet of the catalytic material regeneration module. Through the coordinated operation of the discharge valve and the feeding port, semi-continuous replacement of catalytic material can be achieved in the continuous operation of the system without interrupting the operation of the entire system, which significantly improves the processing efficiency and equipment utilization.

[0026] (5) This invention achieves both volume reduction and efficient conversion of the oil component in oily sludge into high-quality light fuel oil, maximizing resource recovery. The semi-coke produced by pyrolysis can be used as solid fuel or adsorbent material; the non-condensable gas, after purification, can be used as a system heat source or for other purposes, reducing external energy consumption; the reaction water, after treatment, can meet discharge standards or be reused. The entire process achieves thorough volume reduction and resource recovery of oily sludge, with minimal secondary pollution emissions, resulting in good environmental and social benefits.

[0027] In summary, this invention integrates low-temperature pyrolysis and high-temperature catalytic reforming within the same reactor, along with in-situ regeneration and recycling of calcium-based catalytic materials, achieving efficient resource utilization of oily sludge. This significantly improves the quality of light fuel oil, reduces system energy consumption and operating costs, and the device features a compact structure, continuous production capability, and promising prospects for industrial applications. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the yield under different number of cycles in this invention; Figure 2 This is a schematic diagram of acid values ​​under different cycle numbers in this invention. Detailed Implementation

[0029] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0030] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0031] In the following embodiments and comparative examples of the present invention, the oil content of the oily sludge to be treated is 35 wt%, the water content is 15 wt%, and the solid impurity content is 50 wt%.

[0032] Example 1 This embodiment provides a method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge, including the following steps: Oily sludge pretreatment: The oily sludge is dewatered to control its moisture content to be below 8 wt%; then it is crushed and screened to control the particle size to be less than 8 mm, thus obtaining the pretreated oily sludge.

[0033] Preparation of calcium-based catalytic material: Hydroxyapatite was used as a support, and the active component CaO was loaded using an equal-volume impregnation method. The hydroxyapatite support was dried at 105℃ for 4 h, and its saturated water absorption rate was measured. A certain amount of dried support was weighed, and the required loading amount of the active component CaO was calculated based on the target support mass accounting for 40% of the total mass of the catalytic material, thereby determining the amount of the precursor calcium nitrate hexahydrate. The calculated amount of calcium nitrate hexahydrate was dissolved in deionized water to prepare an impregnation solution matching the saturated water absorption rate of the support; the support was immersed in the impregnation solution and allowed to stand at room temperature for 12 h, with intermittent stirring to ensure uniform impregnation; then it was dried at 105℃ for 12 h; finally, it was calcined at 500℃ for 4 h to obtain the calcium-based catalytic material.

[0034] Low-temperature pyrolysis section: Pretreated oily sludge is fed into the low-temperature pyrolysis section of a segmented pyrolysis reactor (micro-tilted rotary kiln) via a feed module. The low-temperature pyrolysis section is 8m long, at 350℃, under a nitrogen atmosphere, and has a residence time of 30 minutes. In this section, the oily sludge undergoes pyrolysis, with light oils volatilizing and heavy colloids and asphaltenes undergoing preliminary cracking, generating primary pyrolysis oil and gas mainly composed of medium- and long-chain alkanes, olefins, and oxygen-containing compounds, while also producing pyrolysis semi-coke rich in fixed carbon. The semi-coke is discharged from the end of the section and can be used as solid fuel or adsorbent material.

[0035] High-Temperature Catalytic Reforming Section: Primary pyrolysis oil and gas are carried by nitrogen into the high-temperature catalytic reforming section, which is connected to the low-temperature pyrolysis section (a throttling device is installed between the two sections to prevent gas backmixing). The high-temperature catalytic reforming section is 5m long and operates at 520℃. It is filled with calcium-based catalyst material, filling 30% of its volume. The residence time of the primary pyrolysis oil and gas at the catalyst material is 5s. The high-temperature catalytic reforming section contains a CO2 atmosphere. Under this atmosphere, the surface portion of the calcium-based catalyst material is converted to CaCO3, forming a CaO-CaCO3 composite active center. The basic sites of CaO catalyze the deoxygenation reaction of oxygen-containing compounds (such as carboxylic acids and phenols); the hydroxyapatite support provides acidic sites, promoting the cyclization and aromatization of olefins and the selective cracking of long-chain alkanes, and saturating some double bonds through hydrogen transfer reactions on the catalyst surface; simultaneously, the CaO-CaCO3 system continuously adsorbs acidic gases such as CO2 and H2S from the pyrolysis gas through a dynamic cycle of carbonation-decomposition. After undergoing the above-mentioned catalytic reforming reaction, the primary pyrolysis oil and gas are converted into an oil and gas mixture.

[0036] Product separation: The oil-gas mixture is drawn from the outlet of the segmented pyrolysis reactor and sent to the oil-gas separation and collection module. First, it passes through a cyclone separator for dust removal, then enters a condenser to cool to 30°C, achieving gas-liquid separation. The condensate enters an oil-water separator; the separated upper oil phase is light fuel oil, collected in a storage tank; the lower aqueous phase is reaction water, sent for further processing. The non-condensable gas, after being purified to remove acidic components, can be reused as fuel gas for system heating.

[0037] Catalyst regeneration: After 48 hours of reaction, the catalytic material discharge valve at the end of the high-temperature catalytic reforming section is slowly opened. Gravity discharges some of the calcium-based catalytic material whose activity has decreased due to carbon buildup and impurity adsorption. Simultaneously, an equal amount of regenerated catalytic material is replenished through the catalytic material feed port of the high-temperature catalytic reforming section, achieving semi-continuous replacement of the catalytic material without interrupting the entire system. The discharged deactivated catalytic material is transported to the catalytic material regeneration module and calcined at 650℃ in air for 2 hours to burn off surface carbon and decompose CaCO3 to regenerate CaO, restoring its pore structure and catalytic activity. The regenerated catalytic material is mixed with a small amount of fresh catalytic material and returned to the high-temperature catalytic reforming section for recycling via a pneumatic conveying device.

[0038] The components of the obtained light fuel oil were analyzed by gas chromatography-mass spectrometry (GC-MS). Its distillation range distribution was determined according to the "Determination of Atmospheric Distillation Characteristics of Petroleum Products" (GB / T 6536-2010), and its acid value was determined according to the "Determination of Acid Value of Petroleum Products" (GB / T 264-1983).

[0039] Testing revealed that the final yield of light fuel oil obtained in this embodiment (as a percentage of the total oil base in the feedstock) was 86.3%, of which gasoline fraction (<200℃) accounted for 32.5%, diesel fraction (200-350℃) accounted for 47.8%, and heavy fraction (>350℃) accounted for 19.7%. The oil contained 62.5% saturated hydrocarbons, 24.3% aromatics, 8.2% olefins, 5.0% oxygenated compounds, and had an acid value of 0.42 mg KOH / g.

[0040] Example 2 This embodiment provides a method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge, which is basically the same as that in Embodiment 1, except that the support for the calcium-based catalytic material is replaced with acid-treated sepiolite.

[0041] Preparation of acid-treated sepiolite: Sepiolite was placed in a 2 mol / L hydrochloric acid solution with a solid-liquid ratio of 1:10 (g / mL), stirred at 80℃ for 4 h, then filtered and washed until neutral, dried at 105℃ for 12 h, and finally calcined at 500℃ for 4 h to obtain acid-treated sepiolite.

[0042] Using the acid-treated sepiolite as a carrier, calcium-based catalytic materials were prepared according to the same method as in Example 1, wherein the carrier mass accounted for 35% of the total mass of the catalytic materials.

[0043] The remaining steps are the same as in Example 1.

[0044] Using the same method as in Example 1, the yield of light fuel oil obtained in this example was 85.7%, of which gasoline fraction accounted for 31.8%, diesel fraction accounted for 48.2%, and heavy fraction accounted for 20.0%. The oil contained 61.8% saturated hydrocarbons, 25.1% aromatics, 7.9% olefins, 5.2% oxygenated compounds, and had an acid value of 0.45 mg KOH / g.

[0045] Example 3 This embodiment provides a method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge, which is basically the same as that in Embodiment 1, except that some process parameters are adjusted.

[0046] (1) The temperature of the low-temperature pyrolysis section is controlled at 380℃ and the residence time is 25min.

[0047] (2) The temperature of the high-temperature catalytic reforming section is controlled at 480℃ and the residence time is 8s.

[0048] The remaining steps are the same as in Example 1.

[0049] Using the same method as in Example 1, the yield of light fuel oil obtained in this example was 82.4%, of which gasoline fraction accounted for 28.6%, diesel fraction accounted for 52.3%, and heavy fraction accounted for 19.1%. The oil contained 58.7% saturated hydrocarbons, 26.5% aromatics, 9.3% olefins, 5.5% oxygenated compounds, and had an acid value of 0.51 mg KOH / g.

[0050] Comparative Example 1 This comparative example provides a method for single-stage pyrolysis of oily sludge, including the following steps: The oily sludge pretreatment was carried out using the same method as in Example 1.

[0051] The pretreated oily sludge was fed into a conventional pyrolysis reactor and pyrolyzed at 500°C for 40 minutes. The resulting oil-gas mixture was condensed and separated to obtain pyrolysis oil.

[0052] Using the same method as in Example 1, the yield of the pyrolysis oil obtained in this comparative example was 72.5%, of which gasoline fraction accounted for 18.3%, diesel fraction accounted for 32.5%, and heavy fraction accounted for 49.2%. The oil contained 34.2% saturated hydrocarbons, 15.6% aromatics, 28.5% olefins, 21.7% oxygenated compounds, and had an acid value of 3.82 mg KOH / g.

[0053] Comparative Example 2 This comparative example provides a two-stage pyrolysis method, which differs from Example 1 in that the low-temperature pyrolysis and high-temperature catalytic reforming are placed in two separate reactors.

[0054] The specific steps are as follows: Pretreated oily sludge is fed into the first reactor (low-temperature pyrolysis section) and pyrolyzed at 350°C to generate primary pyrolysis oil and gas and semi-coke. The primary pyrolysis oil and gas is extracted and transported via pipeline to the second reactor (high-temperature catalytic reforming section), where it comes into contact with calcium-based catalyst material (same as in Example 1) at 520°C to undergo catalytic reforming, generating an oil-gas mixture. The oil-gas mixture is condensed and separated to obtain pyrolysis oil. After the catalyst material is deactivated, it is removed from the second reactor, regenerated, and refilled.

[0055] Using the same method as in Example 1, the pyrolysis oil yield obtained in this comparative example was 84.8%, with gasoline fraction accounting for 31.9%, diesel fraction accounting for 47.2%, and heavy fraction accounting for 20.9%. The oil contained 61.3% saturated hydrocarbons, 23.9% aromatics, 8.7% olefins, 6.1% oxygenated compounds, and had an acid value of 0.49 mg KOH / g. The oil quality was comparable to that of Example 1, but due to the use of a dual-reactor structure, the system energy consumption was 15% higher than that of Example 1, and catalyst regeneration required interruption of reactor operation, making continuous operation impossible.

[0056] Experimental Example 1 To verify the recyclability of the catalyst material of this invention, a catalyst regeneration-recycling experiment was conducted 10 times consecutively according to the method of Example 1. After each cycle, samples were taken to measure the yield and acid value of light fuel oil (according to the method of Example 1), and the catalyst recyclability test results were obtained and recorded in Table 1. Simultaneously, for clearer comparison, a schematic diagram of the yield at different number of cycles was drawn, as shown below. Figure 1 As shown; a schematic diagram of acid values ​​at different cycle numbers, as shown. Figure 2 As shown.

[0057] Table 1. Test results of catalyst recycling performance

[0058] From Table 1, Figure 1-2 It can be seen that after 10 regeneration cycles, the yield of light fuel oil decreased from 86.3% to 84.6%, a decrease of 1.7 percentage points; the acid value of the oil increased from 0.42 mg KOH / g to 0.50 mg KOH / g, but was still far lower than that of conventional single-stage pyrolysis oil (3.82 mg KOH / g). This indicates that the calcium-based catalyst material of the present invention has good regeneration performance and cycle stability, and can meet the requirements of continuous industrial production.

[0059] Therefore, the present invention, by employing the above-mentioned method and apparatus for preparing light fuel oil through segmented catalytic pyrolysis of oily sludge, integrates low-temperature pyrolysis and high-temperature catalytic reforming in the same reactor, and combines it with in-situ regeneration and recycling of calcium-based catalytic materials, thereby achieving improved quality of light fuel oil, reduced system energy consumption, and recycling of catalysts.

[0060] Finally, it should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge, characterized in that, Includes the following steps: S1. The pretreated oily sludge is fed into the low-temperature pyrolysis section of the segmented pyrolysis reactor and pyrolyzed at 300-450℃ to generate primary pyrolysis oil and gas and semi-coke. S2. Primary pyrolysis oil and gas flow from the low-temperature pyrolysis section into the high-temperature catalytic reforming section set in the segmented pyrolysis reactor. The high-temperature catalytic reforming section is physically connected to the low-temperature pyrolysis section and the temperature is independently controlled. The primary pyrolysis oil and gas comes into contact with the calcium-based catalytic material packed in this section at 450-600℃, and a catalytic reforming reaction occurs to generate an oil and gas mixture. S3. The oil-gas mixture is drawn out from the outlet of the segmented pyrolysis reactor, and after condensation and separation, light fuel oil is obtained; at the same time, the calcium-based catalyst material of the high-temperature catalytic reforming section is discharged, regenerated, and returned to the high-temperature catalytic reforming section for recycling.

2. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 1, characterized in that, In S2, the active component of the calcium-based catalytic material is selected from CaO, and the support is selected from at least one of hydroxyapatite and acid-treated sepiolite.

3. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 2, characterized in that, The mass of the support accounts for 20-50% of the total mass of the calcium-based catalytic material.

4. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 3, characterized in that, In S2, the high-temperature catalytic reforming section contains a CO2 atmosphere, and the calcium-based catalytic material forms a CaO-CaCO3 composite active center under this atmosphere.

5. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 1, characterized in that, In S1, the pyrolysis time of the low-temperature pyrolysis section is 25-35 min.

6. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 1, characterized in that, In S2, the catalytic reforming reaction takes 2-10 seconds.

7. The method for preparing light fuel oil by staged catalytic pyrolysis of oily sludge according to claim 1, characterized in that, In S3, the regeneration process includes calcining the discharged calcium-based catalyst material at 600-800°C in an oxygen-containing atmosphere.

8. An apparatus for producing light fuel oil by staged catalytic pyrolysis of oily sludge according to any one of claims 1-7, characterized in that, include: The segmented pyrolysis reactor has a low-temperature pyrolysis section and a high-temperature catalytic reforming section arranged sequentially along the material movement direction inside, with a temperature isolation zone between the two sections. The high-temperature catalytic reforming section is filled with calcium-based catalytic material. The feeding module is connected to the inlet of the low-temperature pyrolysis section and is used to transport the pretreated oily sludge to the low-temperature pyrolysis section. The catalytic material regeneration module is connected to the high-temperature catalytic reforming section and is used to receive the calcium-based catalytic material discharged from the section and regenerate it, and then return the regenerated calcium-based catalytic material to the high-temperature catalytic reforming section. An oil-gas separation and collection module is connected to the oil-gas outlet of the segmented pyrolysis reactor and is used to condense and separate the oil-gas mixture drawn from the outlet.

9. The apparatus according to claim 8, characterized in that, The high-temperature catalytic reforming section is equipped with a controllable catalytic material discharge valve at its end bottom, which is connected to the inlet of the catalytic material regeneration module.

10. The apparatus according to claim 8, characterized in that, The high-temperature catalytic reforming section is also equipped with a catalytic material feeding port, which is connected to the outlet of the catalytic material regeneration module.

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