A supercritical water desorption-gasification two-step continuous treatment system and method for oily sludge

Abstract

The application discloses a kind of oil-containing sludge supercritical water desorption-gasification two-step method continuous processing system and method, and the supercritical water desorption-gasification two-step method processing oil-containing sludge hydrogen production system is composed of regenerator, thermal desorption device, slag discharge device, gasification hydrogen production device, cooler, gas-liquid separator and other components.The thermal desorption device can realize the reverse temperature gradient direction flow of oil-containing sludge and supercritical water desorption;The gasification hydrogen production device can disperse or fixedly load catalysts of different particle sizes (5-500 mesh) and shape types (granular, powder, regular type), so as to realize the supercritical water gasification hydrogen production of oil-containing sludge desorption residual liquid.The system is compact in structure, simple and convenient to operate, can be continuously and stably operated for a long time, and can reduce the complexity and cost of process, can effectively reduce the temperature and pressure required for oil-containing sludge treatment, realize the efficient harmless treatment of oil-containing sludge and the resource utilization purpose of high-concentration hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of resource utilization technology of organic waste, and relates to a supercritical water gasification hydrogen production technology for organic waste, and particularly to a continuous two-step treatment system and method for supercritical water desorption-gasification of oily sludge. Background Technology

[0002] The supercritical water oily sludge treatment system is designed based on supercritical water oxidation (SCWO) technology. This technology is an emerging green water treatment technology that has been developed in recent years, and it is especially suitable for the treatment of oily sludge.

[0003] In the supercritical state, water (temperature T > 374℃, pressure p > 24MPa) possesses unique physical and chemical properties, such as high diffusivity, strong fluidity, and miscibility with nonpolar substances like oxygen. This allows organic matter in wastewater to react with hydroxyl radicals in an oxygen-rich supercritical medium, transforming it into inorganic small-molecule compounds such as H2, CO2, and salts. Because there is no resistance to heat and mass transfer between phases, this technology significantly increases the reaction rate.

[0004] When treating oily sludge, supercritical water oxidation technology can completely decompose the organic matter in the sludge, including oils and other harmful substances. This treatment method is not only highly efficient but also achieves thorough treatment without secondary pollution; some pollutants can even be treated with energy self-compensation. Therefore, it is considered one of the most advanced technologies for treating waste and hazardous materials to date.

[0005] Patent CN101058404A proposes a supercritical water fluidized bed reactor, which enables efficient gasification of organic waste in a supercritical water environment. However, this reactor has high heat dissipation energy consumption under electric heating conditions, and the temperature control of each reaction section is difficult. At the same time, the residual liquid residence time is relatively short, and the cost of achieving complete gasification is relatively high. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems in the prior art and provide a two-step continuous treatment system and method for oily sludge by supercritical water desorption-gasification.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A two-step continuous treatment system for oily sludge using supercritical water desorption-gasification includes a thermal desorption unit 11, a gasification hydrogen production unit 12, a feeding module, a cooling and depressurization module, a water supply module, and a regenerator 7.

[0009] The top of the thermal desorption device 11 is connected with a feeding module; the first-stage preheated water inlet pipe of the upper part of the thermal desorption device 11 is connected with the regenerator 7; the desorption product outlet of the thermal desorption device 11 is connected with the bottom inlet of the gasification hydrogen production device 12; the top outlet of the gasification hydrogen production device 12 is connected with the regenerator 7; the preheated water inlets of the bottom of the thermal desorption device 11 and the regenerator 7 are both connected with a water supply module; and the regenerator 7 is connected with a temperature reduction and pressure reduction module.

[0010] A guide vane is installed in the internal desorption cavity of the thermal desorption device 11.

[0011] The bottom of the gasification hydrogen production device 12 is loaded with fluidized bed dispersed catalyst; and a plurality of layers of fixed bed filled catalyst are arranged on the upper part of the fluidized bed dispersed catalyst.

[0012] Heating devices are respectively arranged on the outer parts of the thermal desorption device 11 and the gasification hydrogen production device 12.

[0013] The feeding module comprises a high-pressure N2 gas cylinder 8, a storage tank 9 and a feeding device 10; the high-pressure N2 gas cylinder 8 is connected with the storage tank 9; the storage tank 9 is connected with the feeding device 10, and the feeding device 10 is further connected with a feeding pump 1; and a first liquid flow meter 4 is arranged between the feeding pump 1 and the feeding device 10.

[0014] The water supply module comprises a water tank 16, a first-stage preheated water pump 3 and a second-stage preheated water pump 2 which are sequentially connected.

[0015] The temperature reduction and pressure reduction module comprises a cooler 13, a back pressure valve 14 and a gas-liquid separator 15 which are sequentially connected; and the cooler 13 is connected with the outlet of the regenerator 7.

[0016] The first-stage preheated water pump 3 is connected with the regenerator 7; the second-stage preheated water pump 2 is connected with the preheated water inlet of the bottom of the thermal desorption device 11; a third liquid flow meter 6 is arranged between the first-stage preheated water pump 3 and the regenerator 7; and a second liquid flow meter 5 is arranged between the second-stage preheated water pump 2 and the preheated water inlet of the bottom of the thermal desorption device 11.

[0017] The position close to the bottom of the thermal desorption device 11 is connected with a residue discharging device.

[0018] The gas outlet of the gas-liquid separator 15 is connected with a gas collecting device, and the liquid outlet of the gas-liquid separator 15 is connected with the water tank 16.

[0019] Temperature monitoring devices are arranged on the side walls of the thermal desorption device 11 and the gasification hydrogen production device 12; and an atomizing device is arranged at the inlet of the gasification hydrogen production device 12.

[0020] A continuous treatment method for oil-containing sludge by supercritical water desorption-gasification two-step method comprises the following steps:

[0021] Oil-containing sludge desorption treatment: heating the thermal desorption device 11 to a specified temperature, and feeding the oil-containing sludge and high-pressure water into the thermal desorption device 11 to separate the oil-containing wastewater and sludge impurities;

[0022] Oil-containing wastewater resource treatment: adding corresponding fluidized bed catalyst and fixed bed catalyst into the gasification hydrogen production device 12; and heating the gasification hydrogen production device 12, and feeding the oil-containing wastewater into the gasification hydrogen production device 12 from the bottom, so that H2 and CO2 are obtained through reaction, and the gas is discharged from the upper part of the gasification hydrogen production device 12;

[0023] Resource recovery: the gas product and supercritical water mixed hot fluid discharged from the gasification hydrogen production device 12 are subjected to vapor-liquid separation after cooling and pressure reduction, and the resource recovery is completed.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The present application discloses a supercritical water desorption-gasification two-step continuous treatment system and method for oil-containing sludge, which realizes complete treatment of the oil-containing sludge by using the method of supercritical water desorption and gasification; the gasification hydrogen production device is internally provided with fluidized bed dispersion catalyst and a plurality of layers of fixed bed filling catalyst, and the structure of coupling the fluidized bed and the fixed bed realizes the step-by-step synergistic catalysis of the desorption residual liquid of the oil-containing wastewater, improves the reaction efficiency, and thus reduces the temperature required for the treatment of the oil-containing sludge, reduces the heat dissipation energy consumption, and improves the hydrogen production capacity; the thermal desorption device and the gasification hydrogen production device are both provided with temperature monitoring devices and axially adjustable heating devices on the side walls, the temperature is adjusted according to the data monitored by the temperature monitoring devices, so as to realize the adjustment of the temperature of each reaction section; the desorption residual liquid enters the gasification hydrogen production device from the bottom of the gasification hydrogen production device, and the reactants flow out from the top, and the fluidized bed and fixed bed coupling catalysis structure is designed to realize the full reaction of the desorption residual liquid and complete gasification.

[0026] Further, the oil-containing sludge and the first-stage preheated water are fully mixed at the top of the thermal desorption device, so as to avoid the blockage between the guide plate and the thermal desorption cavity; the second-stage preheated water pump is connected to the bottom of the thermal desorption device, so as to further perform secondary treatment on the desorbed oil-containing sludge, and improve the oil removal rate of the oil-containing sludge.

[0027] Further, the system is simple, the core thermal desorption device and the gasification hydrogen production device have relatively simple structures, the complexity of the process is reduced, and thus the treatment cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 Schematic diagram of continuous treatment system for oil sludge supercritical water desorption-gasification two-step method.

[0030] Wherein: 1-feed pump; 2-two-stage preheating water pump; 3-first-stage preheating water pump; 4-first liquid flow meter; 5-second liquid flow meter; 6-third liquid flow meter; 7-heat regenerator; 8-high-pressure N2 cylinder; 9-storage tank; 10-feeding device; 11-thermal desorption device; 12-hydrogen production device by gasification; 13-cooler; 14-back pressure valve; 15-gas-liquid separator; 16-water tank. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0033] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0034] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0035] In addition, if the term "horizontal" is used, it is not meant to require absolutely horizontal surfaces, but rather can be slightly inclined. As such, the term "horizontal" is used to merely mean more horizontal than vertical, and thus can be slightly inclined.

[0036] In the description of the embodiments of the present application, it should also be noted that, unless specifically defined and limited, if the terms "set", "mounted", "connected", "linked" appear, they should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected, can be mechanically connected, or electrically connected, can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] The present application will be further described in detail below with reference to the accompanying drawings:

[0038] Referring to Figure 1 The oil-containing sludge supercritical water desorption-gasification two-step continuous treatment system comprises a thermal desorption device 11, a hydrogen production device 12, a feed pump 1, a first-stage preheated water pump 3, a second-stage preheated water pump 2, a first liquid flow meter 4, a second liquid flow meter 5, a third liquid flow meter 6, a regenerator 7, a high-pressure N2 cylinder 8, a storage tank 9, a feeding device 10, a cooler 13, a back pressure valve 14, a gas-liquid separator 15, and a water tank 16.

[0039] The oil-containing sludge inlet pipe is connected to the feeding device 10 at the top of the thermal desorption device 11. The desorption cavity inside the thermal desorption device 11 is provided with a guide plate. One end of the guide plate is connected to the desorption cavity with an angle, and the other end is not connected to the desorption cavity with a spacing. The side wall near the top of the thermal desorption device 11 is provided with a first-stage preheated water inlet pipe connected to the regenerator 7. The deionized water is preheated by the regenerator 7 and then enters the first-stage preheated water inlet pipe. The preheated deionized water at this time is called first-stage preheated water. The lower part of the thermal desorption device 11 is provided with a desorption product outlet pipe connected to the hydrogen production device 12. The second-stage preheated water inlet pipe connected to the second-stage preheated water pump is arranged at the bottom of the thermal desorption device 11, which can realize the secondary desorption of the oil component in the ash after the desorption of the oil-containing sludge, and improve the oil removal rate of the oil-containing sludge. The slag discharge device is arranged near the bottom of the thermal desorption device 11.

[0040] The gasification hydrogen production device 12 is internally provided with fluidized bed dispersed catalyst and fixed bed packed catalyst; the bottom of the gasification hydrogen production device 12 is provided with a desorption product inlet pipe, the oil-containing wastewater from the thermal desorption device 11 enters the inside of the gasification hydrogen production device 12 through the desorption product inlet pipe, and then is treated by the fluidized bed dispersed catalyst and the fixed bed packed catalyst to generate H2 and CO2; the generated gas is discharged through the gas phase product outlet of the gasification hydrogen production device 12; the desorption product inlet pipe of the gasification hydrogen production device 12 is provided with a connecting gravity one-way valve and is connected with an atomizing device.

[0041] The oil-containing sludge inlet pipe at the top of the thermal desorption device 11 is connected with the feeding device 10; the upper-middle first-stage preheated water inlet pipe of the desorption device 11 is connected with the regenerator 7, the regenerator 7 is connected with the first-stage preheated water pump 3, and a third liquid flow meter 6 is arranged between the regenerator 7 and the first-stage preheated water pump 3; the lower-middle desorption product outlet pipe of the thermal desorption device 11 is connected with the gasification hydrogen production device 12; the bottom of the thermal desorption device 11 is connected with the second-stage preheated water inlet pipe and the second-stage preheated water pump 2; the feeding device 10 is connected with the feeding pump 1 and the storage tank 9, and a first liquid flow meter 4 is arranged between the feeding device 10 and the feeding pump 1; the storage tank 9 is connected with a high-pressure N2 gas cylinder 8; the regenerator 7 is connected with a cooler 13, the outlet of the cooler 13 is connected with the inlet of a gas-liquid separator 15, and a back pressure valve 14 is arranged between the cooler 13 and the gas-liquid separator 15; the feeding pump 1, the first-stage preheated water pump 3 and the second-stage preheated water pump 2 are all connected with a water tank 16.

[0042] The working process of the present application is as follows:

[0043] The oil-containing sludge material stored in the storage tank 9 is injected into the feeding device 10 by the pressure provided by the high-pressure N2 gas cylinder 8. The deionized water in the water tank 16 is pressurized by the feeding pump 1 and injected into the top of the thermal desorption device 11, and the deionized water in the water tank 16 is pressurized by the first-stage preheated water pump 3, heated in the regenerator 7 by exchanging heat with the hot fluid from the outlet of the gasification hydrogen production device 13, and then forms first-stage preheated water and enters the upper-middle part of the thermal desorption device 11. The first-stage preheated water and the oil-containing sludge flow in the opposite direction of the temperature gradient in the thermal desorption device 11 and gradually increase in temperature, and the oil component in the oil-containing sludge is dissolved into the supercritical water and then forms oil-containing sludge desorption residual liquid and exits from the lower part of the thermal desorption device 11 and enters the gasification hydrogen production device 12 to generate H2 and CO2 by gasification, and the generated gas product and the mixed hot fluid of supercritical water are cooled in the regenerator 7, then enter the cooler 13 and are cooled to room temperature, then enter the gas-liquid separator 15 after being depressurized by the back pressure valve 14, and then are separated, the clean water returns to the water tank 16, and the gas product is collected by a gas collecting device. The bottom side wall of the thermal desorption device 11 is connected with a slag discharge device, and the bottom is connected with the second-stage preheated water pump 2, so that the oil component in the ash after desorption of the oil-containing sludge can be secondarily desorbed, and the oil removal rate of the oil-containing sludge is improved.

[0044] The oily sludge is fed from the top end of the thermal desorption device 11, the first-stage preheated water is introduced from the upper side wall of the thermal desorption device 11, and the oily sludge is rapidly mixed with the first-stage preheated water at the top of the thermal desorption device 11, so that the plugging of the desorption cavity in the thermal desorption device 11 by the oily sludge can be avoided.

[0045] The supercritical water low-temperature high-efficiency two-step treatment of oily sludge for hydrogen production technology can realize the resource utilization, harmless treatment and reduction of oily sludge by using the unique physical and chemical properties of supercritical water.

[0046] The second-stage preheated water is injected from the bottom of the thermal desorption device 11, so that the oil component in the ash after desorption of the oily sludge can be secondarily desorbed, and the oil removal rate of the oily sludge can be improved.

[0047] The experimental system of the supercritical water low-temperature high-efficiency two-step treatment of oily sludge for hydrogen production technology can directly use high salinity water, the water resource can be recycled, a large amount of water pretreatment equipment is saved, and the one-time investment and operation cost are reduced.

[0048] The supercritical water low-temperature high-efficiency two-step treatment of oily sludge for hydrogen production technology has wide material applicability and is not limited to oily sludge, and can also realize the resource utilization, harmless treatment and reduction of other organic waste.

[0049] The supercritical water desorption-gasification two-step continuous treatment method for oily sludge comprises the following steps:

[0050] Oily sludge desorption treatment: the thermal desorption device 11 is heated to a specified temperature, the oily sludge and high-pressure water are introduced into the thermal desorption device 11 to separate the oily wastewater and impurities such as sludge;

[0051] Oily wastewater resource treatment: the corresponding fluidized bed catalyst and fixed bed catalyst are added to the gasification hydrogen production device 12; the gasification hydrogen production device 12 is heated again, the oily wastewater is introduced from the bottom into the gasification hydrogen production device 12, and H2 and CO2 are obtained through reaction, and the gas is discharged from the upper part of the gasification hydrogen production device 12;

[0052] Resource recovery: the gas product and the supercritical water mixed hot fluid discharged from the gasification hydrogen production device 12 are subjected to vapor-liquid separation after cooling and pressure reduction, and the resource recovery is completed.

[0053] The above is only a preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A two-step continuous treatment system for oily sludge using supercritical water desorption-gasification, characterized in that, It includes a thermal desorption unit (11), a gasification hydrogen production unit (12), a feed module, a cooling and depressurization module, a water supply module, and a regenerator (7). The top of the thermal desorption device (11) is connected to the feeding module; the primary preheating water inlet pipe at the top of the thermal desorption device (11) is connected to the regenerator (7); the desorption product outlet of the thermal desorption device (11) is connected to the bottom inlet of the gasification hydrogen production device (12); the top outlet of the gasification hydrogen production device (12) is connected to the regenerator (7); the preheating water inlet at the bottom of the thermal desorption device (11) and the regenerator (7) are both connected to the water supply module; the regenerator (7) is connected to the cooling and depressurization module. The internal desorption chamber of the thermal desorption device (11) is equipped with a guide plate; The bottom of the gasification hydrogen production device (12) is equipped with a fluidized bed dispersed catalyst; the upper part of the fluidized bed dispersed catalyst is provided with several layers of fixed bed packed catalyst. The thermal desorption device (11) and the gasification hydrogen production device (12) are respectively equipped with heating devices on the outside.

2. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 1, characterized in that, The feeding module includes a high-pressure... Gas cylinder (8), storage tank (9), and feeding device (10); the high pressure The gas cylinder (8) is connected to the storage tank (9); the storage tank (9) is connected to the feeding device (10), and the feeding device (10) is also connected to the feeding pump (1); a first liquid flow meter (4) is provided between the feeding pump (1) and the feeding device (10).

3. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 1, characterized in that, The water supply module consists of a water tank (16), a primary preheating water pump (3), and a secondary preheating water pump (2) connected in sequence.

4. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 1, characterized in that, The cooling and pressure reduction module consists of a cooler (13), a back pressure valve (14), and a gas-liquid separator (15) connected in sequence; the cooler (13) is connected to the outlet of the regenerator (7).

5. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 3, characterized in that, The primary preheating water pump (3) is connected to the regenerator (7); the secondary preheating water pump (2) is connected to the preheating water inlet at the bottom of the thermal desorption device (11).

6. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 5, characterized in that, A third liquid flow meter (6) is provided between the primary preheating water pump (3) and the regenerator (7); a second liquid flow meter (5) is provided between the secondary preheating water pump (2) and the preheating water inlet at the bottom of the thermal desorption device (11).

7. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 1, characterized in that, The thermal desorption device (11) is connected to the slag discharge device near the bottom.

8. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification as described in claim 4, characterized in that, The gas outlet of the gas-liquid separator (15) is connected to a gas collection device, and the liquid outlet of the gas-liquid separator (15) is connected to a water tank (16).

9. The two-step continuous treatment system for oily sludge using supercritical water desorption-gasification according to claim 1, characterized in that, Temperature monitoring devices are provided on the side walls of both the thermal desorption device (11) and the gasification hydrogen production device (12); an atomizing device is provided at the inlet of the gasification hydrogen production device (12).

10. A two-step continuous treatment method for oily sludge using supercritical water desorption-gasification, characterized in that, The two-step continuous treatment system for oily sludge based on any one of claims 1-9, using supercritical water desorption-gasification, includes the following steps: Oily sludge desorption treatment: Heat the thermal desorption device (11) to the specified temperature, and pass the oily sludge and high-pressure water into the thermal desorption device (11) to complete the separation of oily wastewater and sludge; Oily wastewater resource utilization treatment: Add the corresponding fluidized bed catalyst and fixed bed catalyst to the gasification hydrogen production device (12); reheat the gasification hydrogen production device (12), and pass the oily wastewater into the gasification hydrogen production device (12) from the bottom. After the reaction, H2 and CO2 are obtained, and the gas is discharged from the top of the gasification hydrogen production device (12). Resource recovery: The gaseous products and supercritical water mixed hot fluid discharged from the gasification hydrogen production unit (12) are cooled and depressurized before being separated into gas and liquid to complete resource recovery.

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