Method for the multistage pyrolysis of mineral oil-containing waste and municipal sludge with simultaneous recovery of ammonia and production of fuel gas

Abstract

The present application relates to a method for multistage pyrolysis of mineral oil-containing waste and municipal sludge, ammonia recovery and preparation of fuel gas, comprising: mixing and pretreating the mineral oil-containing waste and the municipal sludge to obtain a mixture; subjecting the mixture to first-stage high-temperature pyrolysis to obtain high-temperature pyrolysis gas and mixed semi-coke; subjecting the high-temperature pyrolysis gas and the mixed semi-coke to second-stage medium-temperature adsorption, wherein heavy tar in the high-temperature pyrolysis gas is condensed and then adsorbed by the mixed semi-coke; subjecting the product obtained in step S3 to third-stage low-temperature adsorption, wherein light tar in the gas is condensed and then adsorbed by the mixed semi-coke, and then separating to obtain coke-carrying semi-coke and ammonia-rich pyrolysis gas; subjecting the ammonia-rich pyrolysis gas to ammonia recovery treatment to obtain an ammonia-rich product and deaminated non-condensable gas; and subjecting the coke-carrying semi-coke and the deaminated non-condensable gas to high-temperature gasification treatment to obtain hydrogen-rich synthesis gas and gasification slag.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically involving a method for multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and urban sludge. Background Technology

[0002] Mineral oil-containing waste is a hazardous waste generated during petroleum extraction, refining, storage, and transportation. It is characterized by high calorific value and high oil content, such as oily sludge and oil-based drill cuttings. The most thorough treatment method for mineral oil-containing waste is gasification. However, the heavy hydrocarbons it contains easily generate large amounts of tar, leading to equipment blockage and operational interruptions, seriously affecting the continuous and stable operation of the system.

[0003] Urban sludge is a byproduct of wastewater treatment, produced in huge quantities. It has a high organic matter content and contains a large amount of biological nitrogen (nitrogen content as high as 3.3-7.7 wt%). In traditional pyrolysis or gasification processes, this nitrogen is easily converted into gaseous pollutants such as NH3 and HCN and released, which not only corrodes equipment but also increases the load and cost of subsequent tail gas denitrification.

[0004] Therefore, mineral oil-containing waste and urban sludge are both solid wastes containing organic matter, and when treated separately, they both face serious pollution and corrosion problems. Summary of the Invention

[0005] To address the above problems, this invention provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, comprising:

[0006] S1: Mix mineral oil-containing waste with municipal sludge for pretreatment to obtain a mixture;

[0007] S2: The mixture undergoes a first-stage high-temperature pyrolysis to obtain high-temperature pyrolysis gas and mixed semi-coke;

[0008] S3: High-temperature pyrolysis gas and mixed semi-coke undergo a second-stage medium-temperature adsorption process. After the heavy tar in the high-temperature pyrolysis gas is condensed, it is adsorbed by the mixed semi-coke.

[0009] S4: The product obtained in step S3 undergoes a third-stage low-temperature adsorption. The light tar in the gas is condensed and adsorbed by the mixed semi-coke, and then separated to obtain the coke-carrying semi-coke and ammonia-rich pyrolysis gas.

[0010] S5: The ammonia-rich pyrolysis gas is subjected to ammonia recovery treatment to obtain ammonia-rich products and deammoniated non-condensable gas.

[0011] S6: The coke-carrying semi-coke and deammoniated non-condensable gas are subjected to high-temperature gasification to obtain hydrogen-rich syngas and gasification slag.

[0012] This invention treats mineral oil-containing waste and municipal sludge by mixing, but not by simple mixed pyrolysis. Direct mixed pyrolysis produces extremely complex gases, rich in tar vapor and NH3. If a conventional high-temperature direct-flow gasification process is used, a large amount of NH3 enters the gasifier, increasing the denitrification load on the syngas, which is then converted into nitrogen oxides during combustion. If a conventional condensation separation process is used, the tar and ammonia-containing water condense simultaneously, forming extremely difficult-to-treat ammonia-containing waste liquid and low-quality tar emulsions, causing secondary pollution and resource waste.

[0013] This invention designs a three-stage, temperature-decreasing pyrolysis and in-situ semi-coke adsorption process. The porous mixed semi-coke produced by the first-stage high-temperature pyrolysis serves as a transfer adsorption carrier for tar. In the second and third stages of adsorption, tar is adsorbed in a stepwise manner into the solid phase (mixed semi-coke), while NH3 is retained in the gas phase. This solves the technical problems of easy clogging by tar in oily waste and the high-nitrogen, easily polluting, and difficult-to-separate urban sludge, achieving deep removal and full-scale high-value utilization of high-nitrogen, high-oil hazardous waste. In step S5, high-value ammonia resources can be recovered. Tar from mineral oil-containing waste is almost entirely adsorbed into the mixed semi-coke, followed by high-temperature gasification (reforming and cracking), achieving gas-solid decoupling treatment of "coke preservation and nitrogen removal".

[0014] Optionally, in step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:(0.5-3), preferably 1:(1-2). By controlling the dry basis mass ratio of the two raw materials within a suitable range, the mixture has a suitable organic matter content and ash composition, which can provide sufficient volatile matter for subsequent pyrolysis and produce a sufficient number of porous mixed semi-cokes as tar adsorbents with good adsorption performance.

[0015] Optionally, in step S1, the pretreatment specifically involves low-temperature drying to reduce the moisture content of the mixture to no more than 20 wt%, preferably no more than 15 wt%. This reduces the energy consumption of subsequent pyrolysis and ensures the stability of the pyrolysis process. This invention does not have specific requirements for the specific method of low-temperature drying; any drying method well-known in the art can be used, such as low-temperature drying, fluidized bed drying, or natural air drying.

[0016] Optionally, step S2 specifically involves: feeding the mixture into a primary pyrolysis furnace for deep pyrolysis at 500-600°C, where the organic matter is fully volatilized and decomposed. The resulting high-temperature pyrolysis gas includes tar-rich steam, ammonia, and non-condensable gases, while simultaneously producing a mixed semi-coke with a rich porous structure. The inventors have discovered that the mixed semi-coke has a large specific surface area and a well-developed porous structure, making it a relatively good adsorbent material.

[0017] Further optionally, the temperature of the first-stage high-temperature pyrolysis is preferably 520-580℃; the pyrolysis time of the mixture depends on the amount of material processed, and is usually 30-90 min.

[0018] Optionally, step S3 specifically involves: inputting the high-temperature pyrolysis gas and the mixed semi-coke into a secondary adsorption tower, where adsorption is carried out at 350-450℃. The heavy tar (with a high boiling point) in the high-temperature pyrolysis gas condenses and is adsorbed by the mixed semi-coke.

[0019] The mixed semi-coke of this invention is derived from urban sludge and mineral oil-containing waste. The mesoporous or microporous structure of the mixed semi-coke can generate a capillary condensation effect, trapping heavy tar macromolecules in the pores. At the same time, the oxygen-containing functional groups on the surface of the mixed semi-coke form chemical bonds with the aromatic molecules of heavy tar, realizing the efficient transfer of gaseous tar to a solid carrier.

[0020] Further optionally, the temperature of the second-stage medium-temperature adsorption is preferably 380-420℃, which can save energy, promote the full condensation of heavy tar, and prevent the light tar from condensing prematurely.

[0021] Optionally, step S4 specifically involves: inputting the solid product obtained in step S3 and the pyrolysis gas into a three-stage adsorption tower for adsorption at 200-300℃. The light tar (with a low boiling point) in the pyrolysis gas condenses and is adsorbed and retained by the mixed semi-coke; the mixed semi-coke becomes coke-carrying semi-coke, and the pyrolysis gas after tar removal becomes ammonia-rich pyrolysis gas. The ammonia-rich pyrolysis gas is discharged from the exhaust port, and the coke-carrying semi-coke is discharged from the slag discharge port. The liquid tar content in the ammonia-rich pyrolysis gas is extremely low, creating favorable conditions for subsequent efficient ammonia recovery.

[0022] Alternatively, the preferred temperature for the third-stage low-temperature adsorption is 220-280℃, which can save energy and promote the full condensation of light tar.

[0023] Optionally, in step S5, the ammonia-rich pyrolysis gas is fed into the ammonia absorption tower, and the ammonia is separated from the gas phase by the reaction or dissolution of the ammonia with the absorption medium using existing water washing or acid washing processes. The ammonia-rich product obtained by the water washing process is ammonia water, and the ammonia-rich product obtained by the acid washing process (such as dilute sulfuric acid absorption) is an ammonium salt (such as ammonium sulfate).

[0024] The gas discharged from the ammonia absorption tower is a clean, deammoniated, non-condensable gas, whose main components are combustible components such as CO, H2, and CH4.

[0025] In this invention, since the pyrolysis gas has been completely de-tarned in the preceding multi-stage pyrolysis adsorption treatment, the engineering problems of tar clogging the absorption tower packing and polluting ammonia water by-products in traditional processes are avoided.

[0026] Optionally, step S6 specifically involves: feeding coke-carrying semi-coke, deammoniation-removed non-condensable gas, and gasifying agent into the gasifier. The gasifying agent includes saturated steam and oxygen, with the oxygen volume fraction being 5-15%.

[0027] The molar ratio of saturated water vapor to total carbon is 1:(2.0-3.5), and the gasification temperature is 850-950℃. The total carbon mentioned above refers to the number of moles of carbon in the coke-carrying semi-coke.

[0028] Further optionally, the molar ratio of saturated water vapor to total carbon is 1:(2.5-3.0); the gasification temperature is 880-920℃.

[0029] The pores of the coke-carrying semi-coke contain adsorbed tar. The coke-carrying semi-coke, obtained from mineral oil-containing waste and municipal sludge, contains alkali metals / alkaline earth metals (K, Na, Ca, Mg, etc.). The deammoniation-free non-condensable gas is mainly a combustible gas. The coke-carrying semi-coke and the deammoniation-free non-condensable gas are simultaneously introduced into the gasifier with a gasifying agent. At high temperature, the tar in the pores undergoes instantaneous flash evaporation and, under the catalytic action of the alkali metals / alkaline earth metals, undergoes a deep reforming and cracking reaction with the deammoniation-free non-condensable gas, converting into H2 and CO. This invention adds oxygen to the gasifying agent to maintain the thermal balance of the gasifier. The gasifier is preferably a fluidized bed gasifier, a fixed bed gasifier, or an entrained flow gasifier.

[0030] Preferably, after step S6, the process further includes: subjecting the hydrogen-rich syngas to desulfurization and dust removal purification treatment to obtain a clean hydrogen-rich syngas product that meets the requirements of industrial applications; the gasification slag is used to prepare roadbed materials.

[0031] The main component of gasification slag is stable aluminosilicate minerals. After being tested and found to be harmless, it can be used as aggregate to replace natural sand and gravel in the production of roadbed materials, realizing the full-scale resource utilization of solid waste.

[0032] The method described above in this invention has the following beneficial effects:

[0033] (1) Innovative physical gas-solid decoupling mechanism: This invention breaks the traditional condensation separation mode and pioneers a three-stage pyrolysis process of "gradual temperature reduction + in-situ condensation adsorption of semi-coke". It cleverly uses the mixed semi-coke generated by pyrolysis as a transfer carrier of tar. During the cooling process, heavy / light tar is retained in the solid phase in stages, while NH3 is retained in the gas phase, which solves the problem of the extreme difficulty in separating tar and ammonia mixture.

[0034] (2) High-value recovery of nitrogen pollutants at the source: Since heavy and light tar have been adsorbed by mixed semi-coke, the ammonia-rich pyrolysis gas entering the absorption tower in step S5 is relatively clean. This not only ensures the long-term stable operation of the absorption tower and avoids the engineering problems of tar clogging the absorption tower packing and polluting ammonia water by-products in traditional processes, but also obtains high-purity ammonia water / ammonium salt by-products, completely cutting off the pollution source of a large amount of NH3 entering the gasifier and being converted into NOx.

[0035] (3) In-situ catalytic digestion and high-grade gas production of tar: After the tar-bearing semi-coke that has adsorbed tar enters the gasifier, the tar does not need to be collected in liquid form and re-atomized and pumped. Instead, it undergoes high-temperature flash evaporation directly inside the micropores of the semi-coke. Combined with the catalytic effect of the endogenous alkali metals in the semi-coke, the tar is reformed into hydrogen-rich syngas. The carbon conversion rate can reach more than 95%, realizing the internal digestion and secondary value-added of tar.

[0036] (4) Full-scale recycling and harmless closed loop: This invention co-processes two types of solid waste, mineral oil waste (high oil content) and urban sludge (high nitrogen / high ash content), into hydrogen-rich syngas, ammonia-rich products and roadbed materials, transforming the potential pollution attributes of hazardous / solid waste into favorable factors in each process link, and achieving the ultimate integration of environmental and economic benefits.

[0037] Optionally, the primary pyrolysis furnace is a traditional horizontal rotary pyrolysis furnace with feed at the upstream end, an exhaust port at the top of the downstream end, and a discharge port at the bottom; the exhaust port is connected to the air inlet at the bottom of the secondary adsorption tower via a gas pipe.

[0038] A transfer and processing device is provided between the primary pyrolysis furnace and the secondary adsorption tower, including a first conveying pipe, a first storage hopper, a crushing device, a second storage hopper, and a second conveying pipe connected in sequence. The discharge port is connected to the first conveying pipe to transport the mixed semi-coke to the crushing device for crushing. The second conveying pipe is connected to the solid feeding mechanism at the top of the secondary adsorption tower to input the mixed semi-coke that meets the particle size requirements into the secondary adsorption tower. The mixed semi-coke and the high-temperature pyrolysis gas are in countercurrent contact in the secondary adsorption tower to adsorb and condense the heavy tar.

[0039] Optionally, the secondary adsorption tower is vertical and cylindrical, comprising a discharge chamber, an adsorption chamber, and a gas distribution chamber from top to bottom. A solid feeding mechanism is provided on the side of the discharge chamber. Several horizontal adsorption sections are evenly arranged from top to bottom inside the adsorption chamber for adsorbing heavy tar precipitated after the high-temperature pyrolysis gas is condensed. A discharge mechanism is provided next to the bottommost adsorption section. An air inlet is provided at the bottom of the gas distribution chamber.

[0040] An openable door is provided between the discharge chamber and the adsorption chamber, allowing the solid feeding mechanism to enter the adsorption section of the discharge chamber and then into the adsorption chamber; the discharge mechanism is used to extract the adsorption section at the bottom of the adsorption chamber and then input it into the three-stage adsorption tower for continued adsorption; the bottom of the gas distribution chamber is provided with a gas distribution plate to ensure uniform distribution of the bottom air intake.

[0041] Optionally, the adsorption section is circular and includes, from top to bottom, a top mesh, a mixed semi-coke, and a bottom mesh. Both meshes have a circular frame and a mesh surface inside the frame. The mesh surface is evenly and densely covered with mesh holes, the mesh hole diameter of which is smaller than the mixed semi-coke after being crushed by the crushing device, to prevent the semi-coke from leaking out of the adsorption section. The diameter of the adsorption section is slightly smaller than the inner diameter of the adsorption chamber, allowing it to move horizontally downward within the adsorption chamber. The crushed mixed semi-coke is evenly laid between the two meshes. Under the gravity pressure of the top mesh, the structure of the adsorption section within the adsorption chamber is stable, and the rising airflow will not blow away the top mesh, preventing the mixed semi-coke from flying away. The frames and mesh surfaces of the top mesh and the bottom mesh are both made of biomass material.

[0042] Further optionally, the solid feeding mechanism has two openings on its side, one upper and one lower, for pushing the upper and lower mesh sheets into the solid feeding mechanism, respectively; the top of the solid feeding mechanism has a rotatable feeding hopper, the top of which is connected to the end of the second conveying pipe, and the bottom of the feeding hopper is open and can face the lower mesh sheet below, for spreading the crushed mixed semi-coke onto the lower mesh sheet; the bottom of the solid feeding mechanism has a pushing device for pushing the adsorption section into the discharge chamber.

[0043] Optionally, the side wall between the discharge chamber and the solid feeding mechanism is provided with an openable and closable door; the bottom surface of the discharge chamber is flush with the bottom surface of the solid feeding mechanism to facilitate the transfer of the adsorption part; the bottom of the discharge chamber is provided with an openable and closable door to facilitate the lowering of the adsorption part in the discharge chamber to the top of the adsorption chamber. Attached Figure Description

[0044] Figure 1 A flowchart of a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge;

[0045] Figure 2 This is a schematic diagram of the transmission processing device;

[0046] Figure 3 This is a schematic diagram of a two-stage adsorption tower;

[0047] Figure 4 This is a schematic diagram of a solid feeding mechanism;

[0048] Figure 5 This is a schematic diagram of the adsorption section.

[0049] Among them, 1-first conveying pipe, 2-first storage hopper, 3-crushing device, 4-second storage hopper, 5-second conveying pipe, 6-secondary adsorption tower, 7-clamping component, 8-discharge chamber, 9-adsorption chamber, 10-air distribution chamber, 11-solid feeding mechanism, 12-adsorption section, 13-discharge mechanism, 14-support groove, 15-net plate, 16-lower mesh plate, 17-support column, 18-feeding hopper, 19-pressing component. Detailed Implementation

[0050] Example 1

[0051] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, such as... Figure 1 As shown, it includes:

[0052] S1: Mix mineral oil-containing waste with municipal sludge for pretreatment to obtain a mixture;

[0053] S2: The mixture undergoes a first-stage high-temperature pyrolysis to obtain high-temperature pyrolysis gas and mixed semi-coke;

[0054] S3: High-temperature pyrolysis gas and mixed semi-coke undergo a second-stage medium-temperature adsorption process. After the heavy tar in the high-temperature pyrolysis gas is condensed, it is adsorbed by the mixed semi-coke.

[0055] S4: The product obtained in step S3 undergoes a third-stage low-temperature adsorption. The light tar in the gas is condensed and adsorbed by the mixed semi-coke, and then separated to obtain the coke-carrying semi-coke and ammonia-rich pyrolysis gas.

[0056] S5: The ammonia-rich pyrolysis gas is subjected to ammonia recovery treatment to obtain ammonia-rich products and deammoniated non-condensable gas.

[0057] S6: The coke-carrying semi-coke and deammoniated non-condensable gas are subjected to high-temperature gasification to obtain hydrogen-rich syngas and gasification slag.

[0058] The mineral oil-containing waste includes, but is not limited to, oily sludge, waste mineral oil, oil-based drill cuttings, and oil-contaminated waste.

[0059] In step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:3;

[0060] The mineral oil-containing waste and urban sludge are crushed separately to remove hard lumps before being mixed. Both the mineral oil-containing waste and urban sludge are pre-drained and compressed, with virtually no dripping water. The pretreatment specifically involves low-temperature drying to reduce the moisture content of the mixture to 20 wt%.

[0061] Step S2 specifically involves: feeding the mixture into a primary pyrolysis furnace for deep pyrolysis at 500°C, allowing the organic matter to fully volatilize and decompose, with a processing time of 80 minutes. The mixed semi-coke is then crushed to a particle size of 3-8 mm.

[0062] Step S3 specifically involves feeding the high-temperature pyrolysis gas and the mixed semi-coke into a secondary adsorption tower, where adsorption is carried out at 350°C. The heavy tar (with a high boiling point) in the high-temperature pyrolysis gas condenses and is adsorbed by the mixed semi-coke.

[0063] Step S4 specifically involves: inputting the solid product and pyrolysis gas obtained in step S3 into a three-stage adsorption tower for adsorption at 200°C. The light tar (with a low boiling point) in the pyrolysis gas condenses and is adsorbed and retained by the mixed semi-coke. The mixed semi-coke becomes coke-carrying semi-coke, and the pyrolysis gas after tar removal becomes ammonia-rich pyrolysis gas. The ammonia-rich pyrolysis gas is discharged from the gas outlet, and the coke-carrying semi-coke is discharged from the slag outlet.

[0064] In this example, both adsorption towers use countercurrent adsorption. The pyrolysis gas enters from the bottom of the tower and exits from the top. The mixed semi-coke is input from the top of the tower, adsorbs the tar, and then exits from the bottom.

[0065] In step S5, the ammonia-rich pyrolysis gas is fed into the ammonia absorption tower. Using the existing water washing process, the ammonia is separated from the gas phase through the reaction or dissolution of the absorption medium with the ammonia. The resulting ammonia-rich product is ammonia water.

[0066] The gas discharged from the ammonia absorption tower is a clean, deammoniated, non-condensable gas, whose main components are combustible components such as CO, H2, and CH4.

[0067] Step S6 specifically involves: feeding the coke-carrying semi-coke, deammoniation-removed non-condensable gas, and gasifying agent into the gasifier. The gasifying agent includes saturated steam and oxygen, with an oxygen volume fraction of 5%.

[0068] The molar ratio of saturated water vapor to total carbon is 1:2.0, and the gasification temperature is 850℃.

[0069] Step S6 is followed by: purifying the hydrogen-rich syngas by desulfurization and dust removal to obtain a clean hydrogen-rich syngas product that meets the requirements of industrial applications; the gasification slag is used to prepare roadbed materials.

[0070] The main component of gasification slag is stable aluminosilicate minerals. After being tested and found to be harmless, it can be used as aggregate to replace natural sand and gravel in the production of roadbed materials, realizing the full-scale resource utilization of solid waste.

[0071] Gas chromatography analysis revealed that the hydrogen-rich syngas contained 62 vol% H2, 21 vol% CO, 13 vol% CO2, and 4 vol% CH4. The calculated carbon conversion rate was 97.5%. The gasification slag discharged from the bottom of the gasifier was tested and found to meet national standards for leaching toxicity, making it suitable for use in the preparation of roadbed materials.

[0072] Example 2

[0073] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge, which is the same as that in embodiment 1, except that in step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:2.

[0074] Example 3

[0075] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:1.

[0076] Example 4

[0077] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:0.5.

[0078] Example 5

[0079] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S1, the dry basis mass ratio of the mineral oil-containing waste to the municipal sludge is 1:3.1.

[0080] Table 1. Comparison of specific surface area and hydrogen concentration in gasified gas from the mixed semi-coke of Examples 1-5

[0081]

[0082] The experiment found that the higher the proportion of mineral oil-containing waste in the raw materials, the larger the specific surface area of ​​the mixed semi-coke obtained in step S2. The possible reason is that the mineral oil-containing waste contains tar. The first-stage high-temperature pyrolysis volatilizes and decomposes the tar in the mineral oil-containing waste, and the remaining mineral oil-containing waste can produce more pores or holes. Therefore, the proportion of mineral oil-containing waste will affect the specific surface area of ​​the mixed semi-coke.

[0083] Mineral oil-containing waste contains heavy metals, but the content of alkali metals or alkaline earth metals is not high. Urban sludge contains relatively higher levels of alkali metals or alkaline earth metals. If the amount of urban sludge in the raw material is too low, it will affect the content of alkali metals or alkaline earth metals in the coke and semi-coke, thus affecting the catalytic effect. Therefore, considering the above two points, this invention explores that a dry basis mass ratio of mineral oil-containing waste to urban sludge in the raw material of 1:(1-2) is more suitable.

[0084] Example 6

[0085] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1. The difference is that in step S1, during low-temperature drying, the moisture content of the mixture is reduced to 15 wt%, which can further reduce the energy consumption of subsequent pyrolysis treatment.

[0086] Example 7

[0087] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the primary pyrolysis furnace in step S2 is 520°C.

[0088] Example 8

[0089] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the primary pyrolysis furnace in step S2 is 580°C.

[0090] Example 9

[0091] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the primary pyrolysis furnace in step S2 is 600°C.

[0092] Table 2. Tar vapor content in high-temperature pyrolysis gas of Examples 1 and 7-9

[0093]

[0094] If the pyrolysis temperature is too low, the primary cracking will be incomplete, resulting in low tar yield. However, if the pyrolysis temperature is too high, in addition to increasing energy consumption, it may also trigger a secondary condensation reaction in the tar, generating more difficult-to-process polycyclic aromatic hydrocarbons and carbon deposits, thus reducing gasification efficiency. This invention controls the primary pyrolysis temperature at 500-600℃, which can ensure sufficient pyrolysis while avoiding the negative effects of excessive cracking or condensation.

[0095] Example 10

[0096] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the pyrolysis temperature of the secondary adsorption tower in step S3 is 380°C.

[0097] Example 11

[0098] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the pyrolysis temperature of the secondary adsorption tower in step S3 is 420°C.

[0099] Example 12

[0100] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the secondary adsorption tower in step S3 is 450°C.

[0101] In Examples 1 and 10-12, the content of heavy tar in the pyrolysis gas discharged from the secondary adsorption tower was 9 vol%, 5 vol%, 3 vol%, and 6 vol, respectively. The increase in temperature in the secondary adsorption tower is conducive to the condensation of heavy tar in the high-temperature pyrolysis gas, which is then adsorbed by the mixed semi-coke. However, if the temperature is too high, it is not conducive to the adsorption process, and the adsorption amount is reduced.

[0102] Example 13

[0103] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the three-stage adsorption tower in step S4 is 220°C.

[0104] Example 14

[0105] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the pyrolysis temperature of the three-stage adsorption tower in step S4 is 280°C.

[0106] Example 15

[0107] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in embodiment 1, except that the pyrolysis temperature of the three-stage adsorption tower in step S4 is 300°C.

[0108] In Examples 1 and 13-15, the light tar content in the ammonia-rich pyrolysis gas discharged from the three-stage adsorption tower was 3 vol%, 1 vol%, 0.6 vol%, and 2 vol%, respectively. The increase in temperature inside the three-stage adsorption tower was conducive to the condensation of light tar, which was then adsorbed by the mixed semi-coke. However, similarly, if the temperature was too high, it would not be conducive to the adsorption process, and the adsorption amount would be reduced.

[0109] Example 16

[0110] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the gasification temperature in step S6 is 880°C.

[0111] Example 17

[0112] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the gasification temperature in step S6 is 920°C.

[0113] Example 18

[0114] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that the gasification temperature in step S6 is 950°C.

[0115] Example 19

[0116] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S6, the molar ratio of saturated water vapor to total carbon is 1:2.5.

[0117] Example 20

[0118] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S6, the molar ratio of saturated water vapor to total carbon is 1:3.

[0119] Example 21

[0120] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as that in Embodiment 1, except that in step S6, the molar ratio of saturated water vapor to total carbon is 1:3.5.

[0121] Table 3 Comparison of hydrogen concentration in hydrogen-rich synthesis gas of Examples 1 and 16-21

[0122]

[0123] As shown in the table above, the higher the vaporization temperature, the more complete the vaporization reaction and the higher the hydrogen content in the produced gas. However, if the vaporization temperature is too high, the energy consumption will be high. Therefore, a suitable vaporization temperature range should be selected.

[0124] The saturated steam in the gasifying agent acts as both an oxidant and a reactant in the gasifier. First, the steam reacts with carbon in the coke and semi-coke (water-gas reaction) to produce hydrogen and carbon monoxide. Second, the steam reacts with methane and other light hydrocarbons in the pyrolysis gas (steam reforming reaction), cracking them into hydrogen and carbon monoxide. Third, carbon monoxide further reacts with steam (water-gas shift reaction), converting into hydrogen and carbon dioxide. Therefore, the amount of saturated steam in the gasifying agent affects the hydrogen yield after gasification. Appropriately increasing the amount of steam will continuously drive the above three reactions towards hydrogen production, increasing the volume fraction of hydrogen in the hydrogen-rich syngas.

[0125] Example 22

[0126] This embodiment provides a method for the multi-stage pyrolysis synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, which is the same as in Embodiment 1, except that... Figures 2-5 As shown, the primary pyrolysis furnace is a traditional horizontal rotary pyrolysis furnace with a feed port at the upstream end, an exhaust port at the top of the downstream end, and a discharge port at the bottom; the exhaust port is connected to the air inlet at the bottom of the secondary adsorption tower 6 through a gas pipe.

[0127] A transmission and processing device is provided between the primary pyrolysis furnace and the secondary adsorption tower 6, including a first conveying pipe 1, a first storage hopper 2, a crushing device 3, a second storage hopper 4, and a second conveying pipe 5 connected in sequence. The discharge port is connected to the first conveying pipe 1 to transport the mixed semi-coke to the crushing device 3 for crushing. The second conveying pipe 5 is connected to the solid feeding mechanism 11 at the top of the secondary adsorption tower 6 to input the mixed semi-coke that meets the particle size requirements (3-8mm) into the secondary adsorption tower 6. The mixed semi-coke and the high-temperature pyrolysis gas are in countercurrent contact in the secondary adsorption tower 6 to adsorb and condense the heavy tar.

[0128] The first conveying pipe 1 and the second conveying pipe 5 are both equipped with auger mechanisms to drive the movement of solid materials inside the corresponding conveying pipes; the first storage hopper 2, the crushing device 3 and the second storage hopper 4 are arranged sequentially from top to bottom. When the crushing device 3 processes the mixed semi-coke in batches, the continuous discharge from the primary pyrolysis furnace is temporarily stored in the first storage hopper 2, and the material stored in the second storage hopper 4 can be continuously fed into the secondary adsorption tower 6 through the second conveying pipe 5.

[0129] The high-temperature pyrolysis in the primary pyrolysis furnace simultaneously produces high-temperature pyrolysis gas and mixed semi-coke. The high-temperature pyrolysis gas is directly transported to the primary pyrolysis furnace via gas pipelines, with the pipelines insulated throughout to prevent premature condensation and blockage. The mixed semi-coke is a solid, and its transport speed is slower than that of the high-temperature pyrolysis gas. Furthermore, the mixed semi-coke needs to be crushed by a transmission processing device, further slowing its transport speed. Therefore, the high-temperature pyrolysis gas generated from the same mixture is first fed into the secondary adsorption tower 6, where it is adsorbed by the previously crushed mixed semi-coke. The crushed mixed semi-coke is then fed into the secondary adsorption tower 6 to adsorb the high-temperature pyrolysis gas generated from subsequent pyrolysis of the mixture, achieving continuous operation between the primary and secondary adsorption towers 6.

[0130] The primary pyrolysis furnace continuously produces mixed semi-coke, which is then continuously fed into the first storage hopper 2 via the first conveying pipe 1 for temporary storage. The crushing device 3 has an inlet at the top and an outlet at the bottom, and operates in a batch processing mode, processing the mixed semi-coke contained in the first storage hopper 2 at a time. That is, while the crushing device 3 is processing the semi-coke, the solid output from the primary pyrolysis furnace is temporarily stored in the first storage hopper 2. After processing the semi-coke, the crushing device 3 discharges the semi-coke from the bottom into the second storage hopper 4 for temporary storage, and then continuously feeds it into the secondary adsorption tower 6 via the second conveying pipe 5.

[0131] All the transfer and processing devices are equipped with an outer heat-insulating layer to keep the mixed semi-coke as warm as possible. Of course, the temperature of the mixed semi-coke will also drop during the transfer and processing of the device, but since the operating temperature of the secondary adsorption tower 6 is already lower than that of the primary pyrolysis furnace, the pre-cooling of the mixed semi-coke in the transfer and processing device is also beneficial to the condensation of heavy tar in the secondary adsorption tower 6.

[0132] The first conveying pipe 1 is provided with an inlet branch pipe and an outlet branch pipe. The inlet branch pipe is connected to a nitrogen cylinder, and the outlet branch pipe is connected to the inlet at the bottom of the secondary adsorption tower 6 or the gas pipe upstream of the inlet. Nitrogen is used to purge most of the high-temperature pyrolysis gas in the first conveying pipe 1 to the secondary adsorption tower 6 to prevent the high-temperature pyrolysis gas from condensing in the transmission and processing device.

[0133] Inside the primary pyrolysis furnace, the high-temperature pyrolysis gas generated is mainly located in the upper part of the furnace body and is transported to the secondary adsorption tower 6. Only a very small portion of the high-temperature pyrolysis gas is output with the mixed semi-coke. The inlet branch pipe purges the high-temperature pyrolysis gas from the mixed semi-coke transported to the first feed pipe 1. The nitrogen gas entering the inlet branch pipe is preferably preheated to above 450°C.

[0134] The secondary adsorption tower 6 is vertical and cylindrical, and from top to bottom includes a discharge chamber 8, an adsorption chamber 9, and a gas distribution chamber 10. The side of the discharge chamber 8 is provided with a solid feeding mechanism 11. Several layers of horizontal adsorption sections 12 are evenly arranged from top to bottom inside the adsorption chamber 9 to adsorb the heavy tar precipitated after the high-temperature pyrolysis gas is condensed. The bottom adsorption section 12 is provided with a discharge mechanism 13. The bottom of the gas distribution chamber 10 is provided with an air inlet.

[0135] An openable door is provided between the discharge chamber 8 and the adsorption chamber 9, allowing the solid feeding mechanism 11 to enter the adsorption section 12 of the discharge chamber 8 and then enter the adsorption chamber 9; the discharge mechanism 13 is used to extract the adsorption section 12 at the bottom of the adsorption chamber 9 and then input it into the three-stage adsorption tower for continued adsorption; the bottom of the gas distribution chamber 10 is provided with a gas distribution plate to ensure uniform distribution of the bottom air intake.

[0136] Both the solid feeding mechanism 11 and the discharging mechanism 13 are equipped with insulation layers and heating devices to ensure the internal temperature of these two mechanisms. The discharge chamber 8, the adsorption chamber 9, and the gas distribution chamber 10 are all equipped with heating devices and temperature control devices on their outer sides.

[0137] The adsorption section 12 is circular and includes, from top to bottom, a mesh sheet 15, a mixed semi-coke, and a lower mesh sheet 16. Both mesh sheets have a circular frame and a mesh surface inside the frame. The mesh surface is evenly covered with mesh holes, and the mesh hole diameter is smaller than the mixed semi-coke after being crushed by the crushing device 3, so as to prevent the semi-coke from leaking out of the adsorption section 12. The diameter of the adsorption section 12 is slightly smaller than the inner diameter of the adsorption chamber 9, so it can move horizontally downward within the adsorption chamber 9. The crushed mixed semi-coke is evenly spread between the two mesh sheets. Under the gravity pressure of the mesh sheet 15, the structure of the adsorption section 12 in the adsorption chamber 9 is stable, and the rising airflow will not blow the mesh sheet 15, thus preventing the mixed semi-coke from flying away.

[0138] The frames and mesh surfaces of the upper mesh 15 and lower mesh 16 are made of biomass materials, such as straw, branches, and willow twigs. The frame material is harder than the mesh surface. Biomass has a large surface area and a porous structure, allowing both meshes and the mixed semi-coke to serve as adsorption materials for adsorbing condensed heavy tar. Furthermore, the upper mesh 15 and lower mesh 16 possess a certain degree of toughness to withstand the rising airflow within the secondary and tertiary adsorption towers. After exiting the tertiary adsorption tower, the adsorption unit 12 is broken up, and then the two meshes and the coke-laden fragments are fed into the gasifier for gasification.

[0139] The lower surface of the frame of the lower mesh 16 is provided with several vertically downward extending support columns 17, which facilitates the isolation of the upper and lower adsorption parts 12 in the adsorption cavity 9. The several support columns 17 are evenly distributed along the circumference of the lower mesh 16.

[0140] The upper surface of the frame of the lower mesh 16 is provided with a groove, and the lower surface of the frame of the upper mesh 15 is provided with a downward protruding insertion part for insertion into the groove. The insertion part and the groove are interference fit. Since the frame of biomass material has a certain friction, the insertion part is not easy to detach from the groove, thus preventing the upper and lower meshes 16 from separating during subsequent use.

[0141] This invention does not use a traditional countercurrent-like fluidized bed adsorption method because the freely drifting mixed semi-coke falls too quickly, resulting in insufficient effective adsorption time. Furthermore, as the high-temperature pyrolysis gas rises, it gradually condenses and precipitates heavy tar. This heavy tar slows down during its free ascent, and small droplets may coalesce into larger droplets, potentially falling and reducing the contact adsorption effect with the mixed semi-coke. In a fixed-bed configuration, the mixed semi-coke bed is not easily replaceable.

[0142] The present invention is designed with a multi-layer adsorption section 12. The thickness of each adsorption section 12 is easy to control. When the high-temperature pyrolysis gas passes through the adsorption section 12, it can make stable and sufficient contact with the mixed semi-coke and the two mesh sheets, which is conducive to the adsorption of heavy tar. Even if heavy tar drips, it can be caught and adsorbed by the adsorption section 12 below, which improves the adsorption effect and avoids heavy tar from contaminating the inner wall of the secondary adsorption tower 6.

[0143] In this example, the pyrolysis temperature of the secondary adsorption tower is 420℃, and the pyrolysis temperature of the tertiary adsorption tower is 280℃. The content of heavy tar in the pyrolysis gas discharged from the secondary adsorption tower is 1 vol%, and the content of light tar in the ammonia-rich pyrolysis gas discharged from the tertiary adsorption tower is 0.2 vol%. The adsorption effect of the mixed semi-coke is good.

[0144] The solid feeding mechanism 11 has two openings on its side, one at the top and one at the bottom, for pushing the upper wire mesh 15 and the lower wire mesh 16 into the solid feeding mechanism 11, respectively. The top of the solid feeding mechanism 11 has a rotatable feed hopper 18, the top of which is connected to the end of the second conveying pipe 5. The bottom of the feed hopper 18 is open and faces the lower wire mesh 16, for spreading the crushed mixed semi-coke onto the lower wire mesh 16. The bottom of the solid feeding mechanism 11 has a pushing device for pushing the adsorption section 12 into the discharge chamber 8. The pushing device can use existing technology and is preferably located on the side opposite to the discharge chamber 8.

[0145] The upper middle part of the feeding hopper 18 is rotatably connected to the top surface of the solid feeding mechanism 11. The part of the feeding hopper 18 outside the solid feeding mechanism 11 is fitted with a driven gear. A motor is provided next to the feeding hopper 18. The rotating shaft of the motor is vertically upward and connected to the driving gear. The driven gear and the driving gear mesh with each other and are both horizontal, which are used to drive the feeding hopper 18 to rotate.

[0146] The portion of the feed hopper 18 located inside the solid feeding mechanism 11 has a flat opening structure that is wider at the top and narrower at the bottom, with a trapezoidal longitudinal section. The length of the bottom opening of the feed hopper 18 is slightly smaller than the diameter of the lower screen 16, allowing the input mixed semi-coke to be spread evenly on the screen surface of the lower screen 16. During feeding, the feed hopper 18 rotates simultaneously, and the spread mixed semi-coke forms a circular planar shape.

[0147] The inner wall of the solid feeding mechanism 11 is provided with an annular outward protruding support groove 14. The height of the support groove 14 is the same as the height of the upper opening on the side of the solid feeding mechanism 11. The mesh sheet 15 pushed in from the upper opening can enter the support groove 14 and move along the support groove 14 to the top of the lower mesh sheet 16, so that the upper and lower mesh sheets 16 are aligned.

[0148] The lower opening is at the same height as the bottom surface of the solid feeding mechanism 11, allowing the lower mesh 16 and its support column 17, which are pushed in through the lower opening, to rest flat on the bottom surface of the solid feeding mechanism 11. The opening height of the lower opening is slightly greater than the total height of the lower mesh 16 and its support column 17.

[0149] The solid feeding mechanism 11 is also provided with at least two pressing components 19, which are symmetrically arranged along the radial direction of the mesh sheet 15. The top of the pressing component protrudes through the top surface of the solid feeding mechanism 11. A driving device is provided above the outside of the solid feeding mechanism 11 and is connected to the top of the pressing component, which can control the pressing component to move up and down.

[0150] A retractable flexible insulation sleeve is fitted on the outside of the part of the pressing component that is outside the solid feeding mechanism 11. When the pressing component moves up and down, it causes the insulation sleeve to extend and retract, thus preventing heat from leaking out of the solid feeding mechanism 11.

[0151] When the feed hopper 18 rotates to feed the lower mesh 16, the mesh 15 enters the support groove 14, and a portion of the inner side of the mesh 15 frame protrudes from the support groove 14. Since the mesh 15 is made of biomass, it has a certain elasticity and a certain amount of expansion and contraction allowance. The drive device pushes the pressing component down and pushes the mesh 15 out of the support groove 14, pressing it onto the lower mesh 16, with the insertion part inserting into the groove. Then, the pushing device pushes the adsorption part 12 with the support column 17 into the discharge chamber 8.

[0152] The side wall between the discharge chamber 8 and the solid feeding mechanism 11 is provided with an openable door; the bottom surface of the discharge chamber 8 is flush with the bottom surface of the solid feeding mechanism 11, which facilitates the transfer of the adsorption part 12; the bottom of the discharge chamber 8 is provided with an openable door, which facilitates the lowering of the adsorption part 12 in the discharge chamber 8 to the top of the adsorption chamber 9.

[0153] The discharge chamber 8 is provided with at least two clamping components 7, which are symmetrically arranged along the radial direction of the mesh sheet 15. The top of the clamping component protrudes through the top surface of the discharge chamber 8. The bottom of the clamping component is provided with an openable and closable gripper. A controller is provided above the outside of the discharge chamber 8 and connected to the clamping component, which can control the up and down movement of the clamping component and the opening and closing of the gripper.

[0154] A retractable flexible insulation sleeve is fitted on the outer side of the part of the clamping component outside the discharge chamber 8. When the clamping component moves up and down, it causes the insulation sleeve to extend and retract, preventing heat from leaking out of the discharge chamber 8.

[0155] This invention uses the discharge chamber 8 as a transfer chamber for the input adsorption section 12, preventing direct heat leakage from the interior of the secondary adsorption tower 6. The solid feeding mechanism 11 has a separate heating device that can adjust the heating temperature according to the feeding situation and the condition of the feed mesh, preheating the two meshes and maintaining the temperature of the mixed semi-coke. The discharge chamber 8 can also be temperature-adjusted independently. When the discharge chamber 8 is connected to the solid feeding mechanism 11, the opening of the solid feeding mechanism 11 is closed to prevent heat leakage and reduce the heating load on the discharge chamber 8. When the discharge chamber 8 is connected to the adsorption chamber 9, the door connecting the discharge chamber 8 to the solid feeding mechanism 11 is closed to prevent heat leakage and to isolate the direct connection between the adsorption chamber 9 and the solid feeding mechanism 11.

[0156] After the adsorption unit 12 is pushed into the discharge chamber 8, the discharge chamber 8 is isolated from other chambers and heated separately to the temperature of step S3 (i.e., the temperature of the adsorption chamber 9). Then, the controller controls all clamping components to descend and clamp the frame of the upper and lower mesh sheets 16, suspending the adsorption unit 12. Then, the door at the bottom of the discharge chamber 8 is opened, and the clamping components send the adsorption unit 12 into the adsorption chamber 9, and press down on the clamped adsorption unit 12, and then press down on all adsorption units 12, so that the bottommost adsorption unit 12 in the adsorption chamber 9 falls to the bottom of the adsorption chamber 9, ready for discharge. The distance between two adjacent adsorption units 12 is determined by the support column 17 of the upper adsorption unit 12 (the distance is determined according to the actual situation, for example, the distance is 5-20cm), and the support column 17 of the upper adsorption unit 12 abuts against the top surface of the frame of the mesh sheet 15 of the lower adsorption unit 12.

[0157] Select high-temperature resistant clamping components from existing technologies, such as hydraulically driven mechanical components with cooling systems, which can operate in environments of 300-500°C and are suitable for the temperature inside the secondary adsorption tower 6.

[0158] The discharge chamber 8 has a nitrogen purging function, which can introduce nitrogen to purge the small amount of pyrolysis gas that has entered the discharge chamber 8 and send the pyrolysis gas into the three-stage adsorption tower, thus preventing the pyrolysis gas from entering the solid feeding mechanism 11.

[0159] The adsorption chamber 9 is cylindrical inside and can accommodate the adsorption units 12 stacked one on the top and one on the bottom. The top of the adsorption chamber 9 is provided with an air outlet and is connected to the air inlet of the air distribution chamber 10 of the three-stage adsorption tower through an insulated pipe.

[0160] The discharge mechanism 13 is provided with a feeding chamber door and an operating component on both sides. The feeding chamber door corresponds to the bottom of the adsorption chamber 9. The tail of the operating component protrudes through the side wall of the discharge mechanism 13 and is connected to an external controller to control the extension and retraction of the head of the operating component. It can hook out the bottom adsorption part 12 through the feeding chamber door.

[0161] On the other side of the discharge mechanism 13, there is a discharge hopper door. After the inlet hopper door is closed, nitrogen is purged inside the discharge mechanism 13 to purge the high-temperature pyrolysis gas input through the inlet hopper door. The gas is then returned to the gas distribution chamber 10 through a dedicated pipeline, which also cools the gas distribution chamber 10 and promotes the cooling of the high-temperature pyrolysis gas. The head of the operating component swings, pushing the adsorption section 12 out of the discharge mechanism 13 through the discharge hopper door and into the discharge chamber 8 of the three-stage adsorption tower. The discharge mechanism 13 is equipped with a separate heating device to control its own temperature and cool the adsorption section 12 in advance.

[0162] The structure of the three-stage adsorption tower is the same as that of the two-stage adsorption tower, that is, a vertical cylindrical shape, which includes a discharge chamber, an adsorption chamber and a gas distribution chamber from top to bottom. The side of the discharge chamber is connected to the side of the discharge mechanism 13 with a discharge hopper door. The adsorption chamber is evenly arranged with several layers of horizontal adsorption sections from top to bottom, which are used to adsorb the light tar precipitated after the pyrolysis gas is condensed. The bottom adsorption section is provided with a secondary discharge mechanism. The bottom of the gas distribution chamber is provided with an air inlet.

[0163] An openable door is provided between the discharge chamber and the adsorption chamber, allowing the adsorption section to enter the adsorption chamber; the auxiliary discharge mechanism is used to extract the adsorption section at the bottom of the adsorption chamber and then feed it into the crusher to obtain biomass crushed material and coke semi-coke, which are used as solid raw materials for the gasifier; the bottom of the gas distribution chamber is provided with a gas distribution plate to ensure uniform distribution of bottom air intake.

[0164] The structure and operation of the discharge chamber of the tertiary adsorption tower are the same as those of the tertiary adsorption tower, except for the temperature. The top of the adsorption chamber of the tertiary adsorption tower also has a gas outlet, which is connected to the absorption tower via a pipeline for ammonia recovery. The structure and operation of the auxiliary discharge mechanism are the same as those of the discharge mechanism.

[0165] In this example, the heavy tar content in the pyrolysis gas discharged from the secondary adsorption tower is 1.5 vol%, and the light tar content in the ammonia-rich pyrolysis gas discharged from the tertiary adsorption tower is 0.9 vol%. Compared with Example 1, the secondary adsorption tower in this example has a better adsorption effect on heavy tar, while the tertiary adsorption tower has a better adsorption effect on light tar.

Claims

1. A method for the multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil waste and municipal sludge, characterized in that, include: S1: Mix mineral oil-containing waste with municipal sludge for pretreatment to obtain a mixture; S2: The mixture undergoes a first-stage high-temperature pyrolysis to obtain high-temperature pyrolysis gas and mixed semi-coke; S3: High-temperature pyrolysis gas and mixed semi-coke undergo a second-stage medium-temperature adsorption process. After the heavy tar in the high-temperature pyrolysis gas is condensed, it is adsorbed by the mixed semi-coke. S4: The product obtained in step S3 undergoes a third-stage low-temperature adsorption. The light tar in the gas is condensed and adsorbed by the mixed semi-coke, and then separated to obtain the coke-carrying semi-coke and ammonia-rich pyrolysis gas. S5: The ammonia-rich pyrolysis gas is subjected to ammonia recovery treatment to obtain ammonia-rich products and deammoniated non-condensable gas. S6: The coke-carrying semi-coke and deammoniated non-condensable gas are subjected to high-temperature gasification to obtain hydrogen-rich syngas and gasification slag.

2. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, In step S1, the dry weight ratio of the mineral oil-containing waste to the municipal sludge is 1:(0.5-3); the pretreatment specifically involves low-temperature drying to reduce the moisture content of the mixture to no more than 20 wt%.

3. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, Step S2 specifically involves feeding the mixture into a primary pyrolysis furnace and performing deep pyrolysis at 500-600°C, where the organic matter is fully volatilized and cracked, and the resulting high-temperature pyrolysis gas includes tar-rich steam, ammonia, and non-condensable gas, while simultaneously producing mixed semi-coke rich in porous structures. Step S3 specifically involves: feeding the high-temperature pyrolysis gas and the mixed semi-coke into a secondary adsorption tower, where adsorption is carried out at 350-450℃. The heavy tar in the high-temperature pyrolysis gas condenses and is adsorbed by the mixed semi-coke.

4. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, Step S4 specifically involves: inputting the solid product and pyrolysis gas obtained in step S3 into a three-stage adsorption tower for adsorption at 200-300℃. The light tar in the pyrolysis gas condenses and is adsorbed and retained by the mixed semi-coke. The mixed semi-coke becomes coke-carrying semi-coke, and the pyrolysis gas after tar removal becomes ammonia-rich pyrolysis gas. The ammonia-rich pyrolysis gas is discharged from the gas outlet, and the coke-carrying semi-coke is discharged from the slag discharge outlet.

5. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, Step S6 specifically involves: feeding the coke-carrying semi-coke, deammoniation-removed non-condensable gas, and gasifying agent into the gasifier. The gasifying agent includes saturated steam and oxygen, with the oxygen volume fraction being 5-15%. The molar ratio of saturated water vapor to total carbon is 1:(2.0-3.5), and the gasification temperature is 850-950℃.

6. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, The primary pyrolysis furnace is a horizontal rotary pyrolysis furnace with a feed port at the upstream end and an exhaust port at the top and a discharge port at the bottom at the downstream end; the exhaust port is connected to the air inlet at the bottom of the secondary adsorption tower through a gas pipe. A transfer and processing device is provided between the primary pyrolysis furnace and the secondary adsorption tower, including a first conveying pipe, a first storage hopper, a crushing device, a second storage hopper, and a second conveying pipe connected in sequence. The discharge port is connected to the first conveying pipe to transport the mixed semi-coke to the crushing device for crushing. The second conveying pipe is connected to the solid feeding mechanism at the top of the secondary adsorption tower to input the mixed semi-coke that meets the particle size requirements into the secondary adsorption tower. The mixed semi-coke and the high-temperature pyrolysis gas are in countercurrent contact in the secondary adsorption tower to adsorb and condense the heavy tar.

7. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, The secondary adsorption tower is vertical and cylindrical, and includes a discharge chamber, an adsorption chamber and a gas distribution chamber from top to bottom. A solid feeding mechanism is provided on the side of the discharge chamber. Several horizontal adsorption sections are evenly arranged from top to bottom inside the adsorption chamber to adsorb the heavy tar precipitated after the high-temperature pyrolysis gas is condensed. A discharge mechanism is provided next to the bottom adsorption section. An air inlet is provided at the bottom of the gas distribution chamber. An openable door is provided between the discharge chamber and the adsorption chamber, allowing the adsorption section to enter the adsorption chamber; the discharge mechanism is used to extract the adsorption section at the bottom of the adsorption chamber and then input it into the three-stage adsorption tower for continued adsorption; the bottom of the gas distribution chamber is provided with a gas distribution plate to ensure uniform distribution of the bottom air intake.

8. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 7, characterized in that, The adsorption section is circular and includes, from top to bottom, a top mesh, a mixed semi-coke, and a bottom mesh. Both meshes have a circular frame and an internal mesh surface. The mesh surface is evenly and densely covered with mesh holes, the mesh hole diameter of which is smaller than the mixed semi-coke after being crushed by the crushing device, to prevent the semi-coke from leaking out of the adsorption section. The diameter of the adsorption section is slightly smaller than the inner diameter of the adsorption chamber, allowing it to move horizontally downward within the adsorption chamber. The crushed mixed semi-coke is evenly laid between the two meshes. Under the gravity pressure of the top mesh, the structure of the adsorption section within the adsorption chamber is stable, and the rising airflow will not blow the top mesh, preventing the mixed semi-coke from flying away. The frames and mesh surfaces of the top and bottom meshes are both made of biomass material.

9. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 8, characterized in that, The solid feeding mechanism has two openings on its side, one at the top and one at the bottom, for pushing the upper and lower mesh sheets into the solid feeding mechanism, respectively. The top of the solid feeding mechanism has a rotatable feeding hopper, the top of which is connected to the end of the second conveying pipe. The bottom of the feeding hopper is open and can face the lower mesh sheet below, for spreading the crushed mixed semi-coke onto the lower mesh sheet. The bottom of the solid feeding mechanism has a pushing device for pushing the adsorption section into the discharge chamber.

10. The method for multi-stage pyrolysis and synergistic recovery of ammonia and preparation of fuel gas from mineral oil-containing waste and municipal sludge according to claim 1, characterized in that, The side wall between the discharge chamber and the solid feeding mechanism is provided with an openable and closable door; the bottom surface of the discharge chamber is flush with the bottom surface of the solid feeding mechanism, which facilitates the transfer of the adsorption part; the bottom of the discharge chamber is provided with an openable and closable door, which facilitates the lowering of the adsorption part in the discharge chamber to the top of the adsorption chamber.

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