Energy gradient utilization high-liquid-content oil sludge treatment system and method

Abstract

The invention relates to the technical field of oil-containing sludge analysis and detection, and discloses a high-liquid-content oil sludge treatment system and method with energy gradient utilization. According to the system, a pretreatment device is used for pretreating oil sludge; the three-phase separation and deep dehydration unit is used for dehydrating and deoiling the oil sludge and forming deep dehydrated oil sludge; the heat drying unit is used for carrying out heat drying on the deeply dehydrated oil sludge; the thermal desorption device is connected with the thermal drying unit and is used for pyrolyzing and drying the oil sludge. The method comprises the following steps: pretreatment: removing impurities and / or thermally washing oil sludge; three-phase separation and deep dehydration: dehydrating the oil sludge, deoiling and forming deep dehydrated oil sludge; performing heat drying: performing heat drying on the deeply dehydrated oil sludge to obtain dried oil sludge; and thermal desorption: pyrolyzing and drying the oil sludge. According to the technical scheme, the pretreatment device, the three-phase separation unit, the heat drying unit and the thermal desorption device are matched to realize pretreatment, dehydration, deoiling, heat drying and pyrolysis of the oil sludge, and oil-water-sludge three-phase separation of the oil sludge with high liquid content is realized.

Description

Technical Field

[0001] The invention relates to the technical field of oily sludge analysis and detection, and in particular to a system and method for treating high-liquid oily sludge using energy cascade utilization. Background Art

[0002] Oily sludge is oily sludge, which has extremely complex composition and is a stable suspended solid-liquid system. Oily sludge mainly contains a large amount of aged crude oil, wax, asphaltene, colloid, suspended solids, bacteria, salts, acidic gases and corrosion products, etc. It also includes a large amount of water treatment agents such as coagulants, corrosion inhibitors, scale inhibitors and bactericides added during the production process. The specific resistance of oily sludge is 40 times greater than that of general sludge, and its compressibility coefficient is 20 times greater than that of general sludge. It is difficult to filter sludge; and because of its fine particles, flocculent form, high water content and large volume, it is not easy to achieve the three-phase separation of oil-water-sludge.

[0003] Oily sludge, oil-based mud, oily waste liquid and other substances are all listed as hazardous wastes. According to the oily waste HW08 category in the "National Hazardous Waste Catalogue", oily sludge must be harmlessly treated. Among them, high-water and oil-containing sludges such as oil-based muds are the most difficult to treat. In the prior art, the sludge is often made to reach a solid state with a solid content greater than 70% by remixing dry materials, and then enters the thermal desorption device for treatment. Although this treatment method is simple, it requires repeated heating of the remixed materials, which greatly increases the consumption of fossil energy and reduces the processing capacity of the thermal desorption device. In order to maximize energy conservation and emission reduction, the present invention proposes a high-liquid sludge treatment system and method with energy cascade utilization. Summary of the invention

[0004] The present invention provides a system and method for treating high-liquid-content oil sludge with cascaded energy utilization, so as to solve the above-mentioned technical problem that the treatment effect of high-liquid-content oil sludge in the prior art is not good.

[0005] According to a first aspect of the present invention, there is provided a system for treating high-liquid sludge with energy cascade utilization, comprising:

[0006] A pretreatment device, used for pretreating the oil sludge;

[0007] A three-phase separation + deep dehydration unit connected to the pretreatment unit, used for dehydrating and deoiling the sludge to form deeply dehydrated sludge;

[0008] A thermal drying unit connected to the three-phase separation + deep dehydration unit, used for thermally drying the deep dehydrated sludge to obtain dried sludge; and

[0009] A thermal desorption device connected to the thermal drying unit is used to pyrolyze the dried oil sludge.

[0010] Preferably, the pre-processing device comprises:

[0011] An impurity removal pretreatment unit, used for removing impurities from the sludge raw material; and

[0012] Hot wash pretreatment unit, used for dosing and hot washing sludge;

[0013] Wherein, in the pretreatment device, the pretreatment of the impurity removal pretreatment unit includes crushing, screening, iron removal and metering processes, wherein the crushing process adopts a double-roll crusher and / or a hammer crusher, the screening process adopts a drum screen or a vibrating screen, the iron removal process adopts a permanent magnetic iron remover, and the metering process adopts a single roller belt scale or a lever multi-roller belt scale; and / or

[0014] In the pretreatment device, the hot washing pretreatment unit adopts a jacketed vertical reactor, a jacketed horizontal reactor or a rectangular tank hot washing device, or the hot washing pretreatment unit adopts a jacketed vertical reactor, a jacketed horizontal reactor or a rectangular tank hot washing device and is equipped with a hot washing agent preparation and dosing auxiliary system; and / or

[0015] In the pretreatment device, the internal recycled water and / or sludge generated by the oily wastewater treatment unit is returned to the hot washing pretreatment unit for hot washing to adjust the solid content of the sludge. The oily wastewater treatment unit is connected to a three-phase separation + deep dehydration unit.

[0016] Preferably, in the three-phase separation + deep dehydration unit, the three-phase separation process uses a three-phase horizontal screw centrifuge and / or the deep dehydration process uses a high-pressure steel belt filter or a vertical continuous plate and frame filter press; and / or

[0017] The thermal drying unit uses heat-conducting oil to heat the partition wall, wherein the thermal drying unit uses a hollow paddle dryer, a disc dryer, a thin layer dryer or a fluidized bed dryer; and / or

[0018] The thermal desorption device uses hot flue gas to heat the partition wall, wherein the thermal desorption device uses a jacketed spiral pyrolysis reactor, a jacketed rotary kiln pyrolysis reactor or a chain plate pyrolysis reactor, or the thermal desorption device uses an electrically excited heated spiral or rotary kiln.

[0019] Preferably, the thermal desorption device comprises: a hot air furnace and a thermal desorption unit; or

[0020] The thermal desorption device comprises: a hot air furnace, a thermal desorption unit and an air preheater;

[0021] in,

[0022] The hot blast furnace is used to burn natural gas to generate hot flue gas;

[0023] The thermal desorption unit is connected to the hot air furnace, and the thermal desorption unit is used to heat and pyrolyze the dried oil sludge through hot flue gas;

[0024] The air preheater is connected to the thermal desorption unit and the hot air furnace; the air preheater receives the medium-temperature flue gas discharged from the thermal desorption unit to preheat the drying waste gas, and the preheated drying waste gas is sent to the hot air furnace to assist combustion, wherein the drying waste gas is generated by the thermal drying unit.

[0025] Preferably, the thermal desorption device adopts flue gas reflux for heating; a part of the medium-temperature flue gas discharged from the thermal desorption unit is refluxed, and is sent into the thermal desorption device again for heating along with the hot flue gas generated by the hot blast furnace.

[0026] Preferably, the high-liquid sludge treatment system with energy cascade utilization comprises:

[0027] A spray tower connected to the thermal desorption device; the spray tower is used to remove water vapor, oil vapor, non-condensable gas and a small amount of fly ash in the pyrolysis gas generated by the thermal desorption device to generate non-condensable gas; and

[0028] A condenser is connected to the spray tower; the condenser is used to further remove water and oil in the non-condensable gas to obtain clean pyrolysis non-condensable gas, and the pyrolysis non-condensable gas is used for combustion to provide a heat source.

[0029] Preferably, the high-liquid sludge treatment system with energy cascade utilization comprises:

[0030] a nitrogen generator for providing nitrogen to the thermal desorption device; and / or

[0031] A cooling unit is used to provide circulating cooling water for wastewater cooling, pyrolysis gas condensation, and thermal desorption discharge in the high-liquid sludge treatment system of the energy cascade utilization; and / or

[0032] The heat transfer oil furnace is used to burn the pyrolysis gas generated by the thermal desorption device to recover heat energy, and the recovered heat energy is used for heating materials in the pretreatment device and / or the thermal drying unit.

[0033] According to a second aspect of the present invention, there is provided a method for treating high-liquid sludge with energy cascade utilization, comprising the following steps:

[0034] S1. Pretreatment: removing impurities and / or hot washing the sludge;

[0035] S2. Three-phase separation and deep dehydration: the sludge is dehydrated, deoiled and forms a deeply dehydrated sludge;

[0036] S3. Thermal drying: thermally drying the deep dehydrated sludge to obtain dried sludge;

[0037] S4. Thermal desorption: pyrolyzing the dried oil sludge.

[0038] Preferably, the wastewater generated in the three-phase separation and deep dehydration step is subjected to oily wastewater treatment, and the internal reuse water and / or sludge return generated by the oily wastewater treatment is used for hot washing the sludge to adjust the solid content of the sludge; and / or

[0039] The thermal desorption step is performed in a thermal desorption device, a portion of the medium-temperature flue gas discharged in the thermal desorption step is refluxed and sent into the thermal desorption device again with the newly generated hot flue gas for heating; and / or

[0040] The medium-temperature flue gas discharged in the thermal desorption step is preheated to the drying waste gas in the air preheater, and the preheated drying waste gas is used to assist combustion to newly generate hot flue gas, wherein the hot flue gas is used to pyrolyze and dry the oil sludge, and the drying waste gas is generated by the thermal drying step.

[0041] Preferably, the temperature of the oil sludge hot washing is 70-90°C; and / or

[0042] The deep dehydrated sludge has a solid content of 50% to 80%; and / or

[0043] The solid content of the dried sludge is 70% to 90%; and / or

[0044] In the thermal desorption step, the temperature of the inlet flue gas is 800-900° C.; and / or

[0045] In the thermal desorption step, the pyrolysis temperature is 250-500° C.; and / or

[0046] In the thermal desorption step, the temperature of the exhaust gas is 500-700° C.; and / or

[0047] In the thermal desorption step, the flue gas reflux ratio is reflux flue gas: newly generated flue gas = 4 to 10; and / or

[0048] In the step of preheating the dried exhaust gas with the medium-temperature flue gas in the air preheater, the temperature of the medium-temperature flue gas is reduced to 100° C. before being discharged.

[0049] In the technical solution of the present invention, the cooperation of the pretreatment device, the three-phase separation + deep dehydration unit, the thermal drying unit and the thermal desorption device realizes the pretreatment, dehydration, deoiling, thermal drying and pyrolysis of the sludge, and efficiently realizes the three-phase separation of oil-water-mud in high-liquid-content sludge, thereby maximizing energy conservation and emission reduction.

[0050] Among them, the energy-saving design of the hot blast furnace, the heat recovery of the exhaust gas from the hot blast furnace, and the secondary utilization of the non-condensable gas from pyrolysis realize the cascade utilization of energy in the energy-saving design, which can minimize the gas consumption of the high-liquid sludge treatment system and method of the energy cascade utilization. The energy-saving design of the hot blast furnace significantly improves the thermal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The schematic diagram of the process of treating high-liquid sludge by energy cascade utilization in one embodiment;

[0052] Figure 2 The material balance diagram of the process corresponding to the method for treating high-liquid sludge using energy cascade in an embodiment. DETAILED DESCRIPTION

[0053] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0054] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution in one embodiment will be clearly and completely described below in conjunction with the drawings in one embodiment. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element. Moreover, in the present invention, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0057] Embodiment 1

[0058] Please refer to Figure 1 This embodiment provides a high-liquid oil sludge treatment system for energy cascade utilization. The attached drawing of the dehydration and deoiling system corresponds to the flow diagram of the high-liquid oil sludge treatment method for energy cascade utilization. The dehydration and deoiling system has the following structure:

[0059] 1. The pretreatment device is used to pretreat oil sludge;

[0060] 2. The three-phase separation + deep dehydration unit is connected to the pretreatment unit. The three-phase separation + deep dehydration unit is used to dehydrate and deoil the sludge and form deeply dehydrated sludge;

[0061] 3. The thermal drying unit is connected to the three-phase separation + deep dehydration unit. The thermal drying unit is used to thermally dry the deeply dehydrated sludge to obtain dried sludge;

[0062] 4. The thermal desorption device is connected to the thermal drying unit, and the thermal desorption device is used for pyrolysis and drying of oil sludge.

[0063] In one embodiment, the pretreatment device includes: an impurity removal pretreatment unit and a hot washing pretreatment unit; wherein the impurity removal pretreatment unit is used to remove impurities from the raw materials of the sludge; and the hot washing pretreatment unit is used to add drugs and hot wash the sludge. In the pretreatment device, the high-liquid sludge enters the hot washing pretreatment unit after pretreatment and sorting in the impurity removal pretreatment unit, adjusts the solid content, and adds surfactants, demulsifiers and other agents, heats to 70-90°C, and maintains a washing time of 20-30 minutes. Preferably, the hot washing pretreatment unit adjusts the solid content by returning sewage.

[0064] Afterwards, the sludge is transported to the three-phase separation + deep dehydration unit for dehydration and deoiling. In one embodiment, the oily wastewater treatment unit is connected to the hot wash pretreatment unit and the three-phase separation + deep dehydration unit, and the oily wastewater treatment unit receives the oily wastewater discharged from the three-phase separation + deep dehydration unit for oily wastewater treatment. During the treatment of oily wastewater, the generated oily wastewater enters the oily wastewater treatment unit for oil separation sedimentation, cooling, and flotation treatment, and then enters the sewage deep treatment unit for multi-media filtration + activated carbon adsorption treatment to meet the discharge standards; the generated oil enters the oil tank for storage; the generated deep dehydrated sludge has a solid content of about 50% to 80%, and enters the subsequent thermal drying unit. Among them, preferably, the internal recycled water and / or sludge generated by the oily wastewater treatment unit is returned to the hot wash pretreatment unit for hot washing to adjust the solid content of the sludge.

[0065] In one embodiment, the thermal drying unit uses heat transfer oil for partition heating. The thermal drying unit preferably uses a paddle dryer or a disc dryer, and heats the partition through the heat transfer oil. The thermal drying unit performs thermal drying treatment on the dehydrated sludge to obtain dried sludge with a solid content of 70% to 90%; the dried waste gas passes through a drying spray tower to remove water vapor, and then is heated by an air preheater and incinerated as combustion air for a hot blast furnace.

[0066] In one embodiment, the thermal desorption device uses hot flue gas to heat the partition. Regarding the thermal desorption device, in one embodiment, the thermal desorption device includes: a hot blast furnace and a thermal desorption unit. In another embodiment, the thermal desorption device includes: a hot blast furnace, a thermal desorption unit and an air preheater. Among them, the hot blast furnace is used to burn natural gas to produce hot flue gas; the hot blast furnace adopts full condensation recovery, and the exhaust temperature is lower than 100°C; the thermal desorption unit is connected to the hot blast furnace, and the thermal desorption unit is used to heat and pyrolyze the dried oil sludge through hot flue gas; the air preheater is connected to the thermal desorption unit and the hot blast furnace; the air preheater receives the medium-temperature flue gas discharged from the thermal desorption unit to preheat the drying waste gas, and the preheated drying waste gas is sent to the hot blast furnace to assist combustion, wherein the drying waste gas is generated by the thermal drying unit. Among them, the outlet of the thermal drying unit is directly connected to the inlet of the thermal desorption unit, and the dried sludge directly enters the thermal desorption unit for treatment; the thermal desorption unit preferably adopts the equipment form of a partition heating rotary kiln or a partition heating spiral, and uses natural gas hot flue gas as the heating source; the internal temperature of the thermal desorption unit is 250-500°C, the residence time is 30-120min, and the oil content of the discharged carbon soil can be controlled below 0.3%.

[0067] In one embodiment, the thermal desorption device uses flue gas reflow for heating; a portion of the medium-temperature flue gas discharged from the thermal desorption unit is recirculated, and is sent to the thermal desorption device again for heating along with the hot flue gas generated by the hot blast furnace. In detail, the hot blast furnace of the thermal desorption device uses flue gas reflow technology for temperature adjustment, controls the inlet flue gas temperature entering the thermal desorption unit to 800-900°C, and the flue gas reflow ratio (reflow flue gas: fresh flue gas (i.e., the flue gas newly generated by the hot blast furnace)) is 4-5. The flue gas reflow technology reduces the final exhaust temperature and significantly improves the thermal efficiency of the hot blast furnace.

[0068] The main components of the pyrolysis gas produced by thermal desorption are water vapor, oil vapor, non-condensable gas and a small amount of fly ash. The water vapor, oil vapor, non-condensable gas and a small amount of fly ash in the pyrolysis gas can be effectively removed through the spray tower, and the spray wastewater is returned to the oily wastewater treatment unit; the pyrolysis gas after spray cooling enters the condenser again to further remove the water and oil in the non-condensable gas to obtain clean pyrolysis non-condensable gas; pyrolysis non-condensable gas is a high calorific value fuel gas, which is burned in a thermal oil furnace to recover heat energy and use it as a resource to provide heat source (high-temperature thermal oil) for the thermal washing pretreatment unit and thermal drying unit; due to the difference in water content and oil content of the sludge raw materials, if the heat is insufficient, it is supplemented with natural gas. The combustion exhaust gas of the thermal oil furnace meets the emission standards after exhaust gas treatment.

[0069] Based on this, in one embodiment, a high-liquid sludge treatment system with energy cascade utilization includes: a spray tower and a condenser; the spray tower is connected to a thermal desorption device; the spray tower is used to remove water vapor, oil vapor, non-condensable gas and a small amount of fly ash in the pyrolysis gas generated by the thermal desorption device to produce non-condensable gas; the condenser is connected to the spray tower; the condenser is used to further remove water and oil in the non-condensable gas to obtain clean pyrolysis non-condensable gas, and the pyrolysis non-condensable gas is used to provide a heat source for combustion.

[0070] Based on this, in one embodiment, a high-liquid sludge processing system with energy cascade utilization includes: a thermal oil furnace; the thermal oil furnace is used to burn the pyrolysis gas generated by the thermal desorption device to recover thermal energy; the recovered thermal energy is supplied to the pretreatment device and / or the thermal drying unit for heating the material, wherein the pretreatment device heats the decontaminated sludge, and the thermal drying unit heats the dehydrated sludge.

[0071] In one embodiment, a high-liquid sludge treatment system with energy cascade utilization includes: a nitrogen generator; the nitrogen generator is used to provide nitrogen to a thermal desorption device.

[0072] In one embodiment, the high-liquid-content oil sludge treatment system for energy cascade utilization includes: a cooling unit; the cooling unit is used to provide circulating cooling water for cooling treatment to wastewater cooling, pyrolysis gas condensation, thermal desorption discharge and other links in the high-liquid-content oil sludge treatment system for energy cascade utilization.

[0073] The technical solution of the present system is further described below in combination with possible equipment forms of each unit / device or corresponding processes of each unit / device in the high-liquid sludge treatment system using energy cascade utilization, and the following structure is adopted.

[0074] 1. The pretreatment device is used to pretreat the sludge; the pretreatment includes crushing, screening, iron removal, metering and other processes, wherein the crushing process uses a double-roll crusher or a hammer crusher, or a double-roll crusher and a hammer crusher in combination, and the material with a particle size of less than 30 mm after crushing reaches more than 85% (m / m); the screening process uses a drum screen or a vibrating screen (linear or annular), and after screening, the particle size of the screened material is controlled to be less than 30 mm; the iron remover uses a permanent magnetic iron remover, and its interior uses a composite magnetic system composed of special permanent magnets such as "NdFeB" with high coercivity and high remanence; the metering process uses a single roller belt scale (accuracy: + / -1%) or a lever multi-roller belt scale (accuracy: + / -0.5%);

[0075] 2. The hot washing pretreatment unit is connected to the impurity removal pretreatment unit. The hot washing pretreatment unit adopts a jacketed vertical reactor, a jacketed horizontal reactor or a rectangular tank hot washing device, and can be equipped with a hot washing agent preparation and dosing auxiliary system;

[0076] 3. The three-phase separation + deep dehydration unit is connected to the hot washing pretreatment unit; the three-phase separation process of the three-phase separation + deep dehydration unit adopts a three-phase horizontal screw centrifuge to dehydrate and deoil the sludge and form dehydrated sludge; preferably, in the three-phase horizontal screw centrifuge, the separation factor is greater than 2500, the centrifuge speed is greater than 3000rpm, and the differential speed is adjustable from 2 to 60rpm; the deep dehydration process of the three-phase separation + deep dehydration unit adopts a high-pressure steel belt filter or a vertical continuous plate and frame filter press to deeply dehydrate the centrifuge dehydrated sludge to obtain a high-dryness dehydrated water cake with a solid content of 50% to 70%;

[0077] 4. The thermal drying unit is connected to the three-phase separation + deep dehydration unit to thermally dry the deep dehydrated sludge and obtain dried sludge; the thermal drying unit adopts a hollow paddle dryer, a disc dryer, a thin layer dryer or a fluidized bed dryer;

[0078] 5. The thermal desorption device is connected to the thermal drying unit to pyrolyze and dry the oil sludge; the thermal desorption device adopts a jacketed spiral pyrolysis reactor, a jacketed rotary kiln pyrolysis reactor or a chain plate pyrolysis reactor, and can also adopt an electrically excited heated spiral or rotary kiln.

[0079] Embodiment 2

[0080] Please refer to Figure 1 This embodiment provides a method for treating high-liquid sludge by cascade energy utilization, comprising the following steps:

[0081] S1. Pretreatment: impurity removal and / or hot washing of sludge;

[0082] S2. Three-phase separation + deep dehydration: sludge is dehydrated, deoiled and forms deep dehydrated sludge;

[0083] S3. Thermal drying: thermally drying the deep dehydrated sludge to obtain dried sludge;

[0084] S4. Thermal desorption: pyrolysis and drying of oil sludge.

[0085] In one embodiment, the wastewater generated in the three-phase separation step is subjected to oily wastewater treatment, and the internal recycled water and / or sludge generated by the oily wastewater treatment is recycled, and the recycled water is used for hot washing of the sludge to adjust the solid content of the sludge.

[0086] In one embodiment, the thermal desorption step is performed in a thermal desorption device, and a portion of the medium-temperature flue gas discharged in the thermal desorption step is refluxed and sent into the thermal desorption device again with the newly generated hot flue gas for heating.

[0087] In one embodiment, the medium-temperature flue gas discharged in the thermal desorption step is preheated to the drying waste gas in an air preheater, and the preheated drying waste gas is used to assist combustion to newly generate hot flue gas, wherein the hot flue gas is used to pyrolyze and dry the oil sludge, and the drying waste gas is generated by the thermal drying step.

[0088] In one embodiment, the method for treating high-liquid sludge with energy cascade utilization may have one or more sets of process parameter settings as follows:

[0089] 1. The temperature of hot washing of oil sludge is 70~90℃;

[0090] 2. The solid content of dehydrated sludge is 50% to 80%;

[0091] 3. The solid content of dried sludge is 70% to 90%;

[0092] 4. In the thermal desorption step, the temperature of the inlet flue gas is 800-900°C;

[0093] 5. In the thermal desorption step, the pyrolysis temperature is 250-500°C;

[0094] 6. In the thermal desorption step, the temperature of the exhaust gas is 500-700°C;

[0095] 7. In the thermal desorption step, the flue gas reflux ratio is reflux flue gas: newly generated flue gas = 4-10 or 5-10;

[0096] 8. In the step of preheating the dried exhaust gas with the medium-temperature flue gas in the air preheater, the temperature of the medium-temperature flue gas is reduced to 100°C before being discharged.

[0097] Please refer to Figure 2 This embodiment also provides a material balance diagram of the process corresponding to the high-liquid sludge treatment method using the energy cascade utilization.

[0098] The above-mentioned method for treating high-liquid oil sludge by energy cascade utilization can adopt the high-liquid oil sludge treatment system by energy cascade utilization in Example 1, and the specific structure will not be repeated.

[0099] 1. Energy-saving design of hot air furnace

[0100] The hot blast furnace adopts flue gas reflow technology for temperature adjustment, controls the flue gas temperature entering the thermal desorption unit to 800-900°C, and the flue gas reflow ratio (reflow flue gas: fresh flue gas) is 4-10; the flue gas reflow technology reduces the final exhaust temperature and significantly improves the thermal efficiency of the hot blast furnace; the thermal efficiency without flue gas reflow is: the mixed flue gas temperature is 850°C, the exhaust temperature is 550°C, and the thermal efficiency is (850-550) / 850×100%=35.3%; the thermal efficiency with flue gas reflow is: the natural gas combustion temperature is 1800°C, the exhaust temperature is 550°C, and the thermal efficiency is (1800-550) / 1800×100%=69.4%, which reflects that the thermal efficiency is improved by about 100%.

[0101] 2. Heat recovery from flue gas discharged from hot blast furnace

[0102] The drying waste gas produced by the thermal drying (unit) is a mixture of water vapor and air. After the dehumidification treatment (drying spray tower), it needs to be deodorized (chemical deodorization + biological deodorization). Because its main component is air, mixed with a trace amount of odorous gas, it can be used as combustion air for the hot air furnace for pyrolysis. The exhaust gas temperature of the thermal desorption (unit) is 500-700℃, which has a high utilization value. This medium-temperature flue gas can be heat-exchanged with the drying waste gas of the thermal drying (unit) (in the air preheater). The exhaust temperature is reduced to 100°C, making full use of the waste heat of the flue gas. With this energy-saving measure, the thermal efficiency of natural gas can reach 94.4% (the combustion temperature of natural gas is 1800°C, the final exhaust temperature is 100°C, and the thermal efficiency is (1800-100) / 1800×100%=94.4%). The heat-dried exhaust gas is used as the combustion air of the hot air furnace, which avoids the investment and land use of deodorization equipment, and saves the electricity consumption, water consumption and agent consumption of the deodorization equipment. The above measures achieve multiple effects at one stroke.

[0103] 3. Arrangement of thermal drying and thermal desorption

[0104] The thermal drying unit and the thermal desorption unit are arranged in a vertical direct connection, so that the dried sludge does not need to be cooled down and can make full use of its own heat (100-120°C), saving the heat input of the thermal desorption process and saving the investment, land occupation and operating power consumption of the conveying equipment;

[0105] 4. Secondary utilization of pyrolysis non-condensable gas

[0106] The spray tower and condenser cooperate to produce clean pyrolysis non-condensable gas; the secondary comprehensive utilization of the pyrolysis non-condensable gas can provide heat source for heat washing pretreatment (unit) and thermal drying (unit).

[0107] In summary, through the above energy-saving designs, the gas consumption of the high-liquid sludge treatment system and method with energy cascade utilization can be reduced to the greatest extent.

[0108] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-liquid sludge treatment system with energy cascade utilization, characterized in that: include: A pretreatment device, used for pretreating the oil sludge; A three-phase separation + deep dehydration unit connected to the pretreatment unit, used for dehydrating and deoiling the sludge to form deeply dehydrated sludge; A thermal drying unit connected to the three-phase separation + deep dehydration unit is used to thermally dry the deep dehydrated sludge to obtain dried sludge; and A thermal desorption device connected to the thermal drying unit is used to pyrolyze the dried oil sludge.

2. The high-liquid sludge treatment system with energy cascade utilization according to claim 1 is characterized in that: The pre-processing device comprises: An impurity removal pretreatment unit, used for removing impurities from the sludge raw material; and Hot wash pretreatment unit, used for dosing and hot washing sludge; Wherein, in the pretreatment device, the pretreatment of the impurity removal pretreatment unit includes crushing, screening, iron removal and metering processes, wherein the crushing process adopts a double-roll crusher and / or a hammer crusher, the screening process adopts a drum screen or a vibrating screen, the iron removal process adopts a permanent magnetic iron remover, and the metering process adopts a single roller belt scale or a lever multi-roller belt scale; and / or In the pretreatment device, the hot washing pretreatment unit adopts a jacketed vertical reactor, a jacketed horizontal reactor or a rectangular tank hot washing device, or the hot washing pretreatment unit adopts a jacketed vertical reactor, a jacketed horizontal reactor or a rectangular tank hot washing device and is equipped with a hot washing agent preparation and dosing auxiliary system; and / or In the pretreatment device, the internal recycled water and / or sludge generated by the oily wastewater treatment unit is returned to the hot washing pretreatment unit for hot washing to adjust the solid content of the sludge. The oily wastewater treatment unit is connected to a three-phase separation + deep dehydration unit.

3. The high-liquid sludge treatment system with energy cascade utilization according to claim 1 is characterized in that: In the three-phase separation + deep dehydration unit, the three-phase separation process uses a three-phase horizontal screw centrifuge and / or the deep dehydration process uses a high-pressure steel belt filter or a vertical continuous plate and frame filter press; The thermal drying unit uses heat-conducting oil to heat the partition wall, wherein the thermal drying unit uses a hollow paddle dryer, a disc dryer, a thin layer dryer or a fluidized bed dryer; and / or The thermal desorption device uses hot flue gas to heat the partition wall, wherein the thermal desorption device uses a jacketed spiral pyrolysis reactor, a jacketed rotary kiln pyrolysis reactor or a chain plate pyrolysis reactor, or the thermal desorption device uses an electrically excited heated spiral or rotary kiln.

4. The high-liquid sludge treatment system with energy cascade utilization according to claim 1 is characterized in that: The thermal desorption device comprises: a hot air furnace and a thermal desorption unit; or The thermal desorption device comprises: a hot air furnace, a thermal desorption unit and an air preheater; in, The hot blast furnace is used to burn natural gas to generate hot flue gas; The thermal desorption unit is connected to the hot air furnace, and the thermal desorption unit is used to heat and pyrolyze the dried oil sludge through hot flue gas; The air preheater is connected to the thermal desorption unit and the hot air furnace; the air preheater receives the medium-temperature flue gas discharged from the thermal desorption unit to preheat the drying waste gas, and the preheated drying waste gas is sent to the hot air furnace to assist combustion, wherein the drying waste gas is generated by the thermal drying unit.

5. The high-liquid sludge treatment system with energy cascade utilization according to claim 1 is characterized in that: The thermal desorption device adopts flue gas reflux for heating; a part of the medium-temperature flue gas discharged from the thermal desorption unit refluxes and is sent to the thermal desorption device again for heating along with the hot flue gas generated by the hot blast furnace.

6. The high-liquid sludge treatment system with energy cascade utilization according to any one of claims 1 to 5, characterized in that: The high-liquid sludge treatment system of energy cascade utilization comprises: A spray tower connected to the thermal desorption device; the spray tower is used to remove water vapor, oil vapor, non-condensable gas and a small amount of fly ash from the pyrolysis gas generated by the thermal desorption device to generate non-condensable gas; and A condenser is connected to the spray tower; the condenser is used to further remove water and oil in the non-condensable gas to obtain clean pyrolysis non-condensable gas, and the pyrolysis non-condensable gas is used for combustion to provide a heat source.

7. The high-liquid sludge treatment system with energy cascade utilization according to any one of claims 1 to 5, characterized in that: The high-liquid sludge treatment system of energy cascade utilization comprises: a nitrogen generator for providing nitrogen to the thermal desorption device; and / or A cooling unit is used to provide circulating cooling water for wastewater cooling, pyrolysis gas condensation, and thermal desorption discharge in the high-liquid sludge treatment system of the energy cascade utilization; and / or The heat transfer oil furnace is used to burn the pyrolysis gas generated by the thermal desorption device to recover heat energy, and the recovered heat energy is used for heating materials in the pretreatment device and / or the thermal drying unit.

8. A method for treating high-liquid sludge with cascaded energy utilization, characterized in that: The following steps are involved: S1. Pretreatment: removing impurities and / or hot washing the sludge; S2. Three-phase separation and deep dehydration: the sludge is dehydrated, deoiled and forms a deeply dehydrated sludge; S3. Thermal drying: thermally drying the deep dehydrated sludge to obtain dried sludge; S4. Thermal desorption: pyrolyzing the dried oil sludge.

9. The method for treating high-liquid sludge with cascaded energy utilization according to claim 8, characterized in that: The wastewater generated in the three-phase separation and deep dehydration step is subjected to oily wastewater treatment, and the internal reuse water and / or sludge return generated by the oily wastewater treatment is used for hot washing the sludge to adjust the solid content of the sludge; and / or The thermal desorption step is performed in a thermal desorption device, a portion of the medium-temperature flue gas discharged in the thermal desorption step is refluxed and sent into the thermal desorption device again with the newly generated hot flue gas for heating; and / or The medium-temperature flue gas discharged in the thermal desorption step is preheated to the drying waste gas in the air preheater, and the preheated drying waste gas is used to assist combustion to newly generate hot flue gas, wherein the hot flue gas is used to pyrolyze and dry the oil sludge, and the drying waste gas is generated by the thermal drying step.

10. The method for treating high-liquid sludge with cascaded energy utilization according to claim 8 or 9, characterized in that: The temperature of the oil sludge hot washing is 70-90°C; and / or The deep dehydrated sludge has a solid content of 50% to 80%; and / or The solid content of the dried sludge is 70% to 90%; and / or In the thermal desorption step, the temperature of the inlet flue gas is 800-900° C.; and / or In the thermal desorption step, the pyrolysis temperature is 250-500° C.; and / or In the thermal desorption step, the temperature of the exhaust gas is 500-700° C.; and / or In the thermal desorption step, the flue gas reflux ratio is reflux flue gas: newly generated flue gas = 4 to 10; and / or In the step of preheating the dried exhaust gas with the medium-temperature flue gas in the air preheater, the temperature of the medium-temperature flue gas is reduced to 100° C. before being discharged.

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