A method for reducing viscosity and fluidizing sludge and utilizing a gasification furnace to cooperatively treat sludge

Abstract

The present application obtains the oil sludge fluidized by the action of the viscosity reducing fluidizing agent and stirring mixing; the oil sludge fluidized can be directly pumped into another pipeline parallel with the water coal slurry feeding pipeline, avoiding the direct mixing of the oil sludge and the water coal slurry, so that the stability and fluidity of the water coal slurry are not destroyed; the oil sludge and the water coal slurry are simultaneously pumped into the gasification chamber of the gasification furnace through the nozzle, the organic matter contained in the oil sludge is gasified under the high-temperature reducing atmosphere in the gasification chamber, the inorganic matter contained in the oil sludge and the coal gasification ash are discharged from the gasification chamber into the quenching chamber in the molten state, and finally discharged from the gasification furnace in the form of ash.

Description

Technical Field

[0001] This invention relates to the field of solid or semi-solid hazardous waste treatment technology, and more specifically, to a method for reducing the viscosity of oily sludge through fluidization and co-processing oily sludge using a gasifier. Background Technology

[0002] Oil sludge is an oil-containing solid (or semi-solid) waste generated during crude oil exploration, extraction, gathering, storage, and refining processes. Its main components are oil, mud, and water, and it is classified as hazardous waste. However, due to the large amount of petroleum-based substances it contains, oil sludge has high resource utilization value. Due to the presence of natural emulsifiers such as asphaltene, gums, and solid particles, as well as non-natural emulsifiers such as oil recovery additives, and the effects of multiple mechanical shearing processes, oil sludge often exists in a stable, three-phase (oil, water, and solid) environment, making oil recovery and harmless treatment of oil sludge quite challenging.

[0003] Common oil sludge treatment technologies include extraction, pyrolysis, biological treatment, thermochemical cleaning, modulation-mechanical separation, and ultrasonic treatment. However, these methods generally suffer from problems such as complex processes, low resource utilization, high investment or operating costs, and incomplete treatment.

[0004] CN202010028049.3 relates to a method for treating viscous sludge. The method involves treating the viscous sludge by adding sand to reduce viscosity (adding quartz sand to the sludge and stirring evenly), thermochemical cleaning, and adding a surfactant solution. However, this method is complex and cannot completely render the sludge harmless.

[0005] CN202110686888.9 describes a process where refining sludge is mixed with a hot washing agent and then subjected to hot washing. After mixing and centrifugation, the upper oil phase, the middle aqueous phase, and the lower sludge phase are collected separately. However, this method involves too many hot washing steps, resulting in excessive energy consumption.

[0006] CN202110207592.4 discloses a method for treating heavy oily sludge using high-temperature thermochemical cleaning. The method involves hot washing the heavy oily sludge, separating the oil and non-oil phases, further separating the sludge components from the non-oil phase, and finally performing solid-liquid separation on the aqueous phase. The separated liquid and solid can be reused for hot washing after further treatment. However, this method involves numerous separation steps, resulting in insufficient and inefficient utilization of the oily sludge.

[0007] CN200510095646.3 describes a composite washing agent for extracting crude oil from waste oil sludge, which is formulated from anionic surfactants (sodium dodecyl sulfate), nonionic surfactants (fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether), additives (sodium carboxymethyl cellulose), solvents (propylene glycol methyl ether acetate), and water. Under normal temperature and pressure, the oil content of the treated oil sludge is less than 1%.

[0008] The methods disclosed in the aforementioned patents essentially fall under the category of chemical washing, utilizing the interfacial activity of surfactants (or with the aid of heating) to remove petroleum-based substances from oily sludge. These methods, especially when treating oily sludge with strong emulsification stability, all generate large amounts of oily wastewater that require treatment. Furthermore, chemical washing methods are not thorough in removing oil from oily sludge with strong emulsification stability, failing to achieve the goal of converting oily sludge from hazardous waste to general solid waste.

[0009] Using existing coal gasification furnaces within refining and chemical enterprises to co-process oil sludge contributes to the construction of "zero-waste factories" and saves on outsourcing oil sludge treatment costs. Coal-water slurry, a low-pollution, high-efficiency, pipeline-transportable coal-based fluid fuel, is produced through physical processing of approximately 70% coal, 29% water, and 1% chemical additives. It exhibits good stability and rheological properties. Co-gasifying oil sludge with coal-water slurry, utilizing the high-temperature reducing atmosphere within the gasifier, gasifies the organic matter contained in the oil sludge, thus simultaneously achieving the harmless treatment and resource utilization of the oil sludge. For example, CN201010222414.0 discloses a method for producing syngas from oil sludge, including: pre-treated oil sludge mixed with coal-water slurry and fed into a gasifier, or pre-treated oil sludge and coal-water slurry fed separately into a gasifier, where a gasification reaction is carried out under high-temperature and high-pressure conditions to obtain syngas. The pre-treatment method includes any one or more of the following: filtration, sedimentation separation, solidification, and extraction.

[0010] In petrochemical enterprises, coal gasification units are one of the main production units (primarily used to supply hydrogen to the hydrogenation units of the refining system). The stable operation of the gasification unit has a significant impact on the safe, stable, long-term, full-capacity, and high-quality operation of the hydrogenation units in the refining system. Therefore, when using a gasifier to co-process oil sludge, it is essential to ensure the stable operation of the entire gasification unit. Refining enterprises produce a variety of oil sludge types (e.g., sludge from crude oil / residue oil / oil slurry / sludge tanks, sludge from oily wastewater tanks, sludge from oil separators, scum, maintenance sludge, etc.) with uneven, complex, and variable composition. Their calorific values ​​and properties vary greatly and are unstable, and they also contain various impurities. Feeding oil sludge directly into the gasifier without homogenization treatment is highly likely to cause a decrease in effective gas yield and poor slag discharge, thereby jeopardizing the stable operation of the gasifier. Because coal mills operate in a non-closed manner, directly co-producing coal-water slurry with oily sludge, coal, and water within the mill fails to meet the requirements for explosion-proof, odor-proof, and VOCs-proof requirements of the coal mill slurry preparation plant. Furthermore, the organic matter present in the oily sludge often disrupts the stability and fluidity of the coal-water slurry, potentially causing hard sedimentation or increased viscosity. Using a gasifier with a separate oily sludge channel to co-process the oily sludge can avoid these drawbacks. However, a significant amount of oily sludge is solid or semi-solid, with high viscosity and poor fluidity, making it difficult to directly pump into the gasifier via separate pipelines. However, the oily sludge pretreatment and syngas production method disclosed in patent CN201010222414.0 does not address these technical problems. Furthermore, the surfactants used in the petroleum industry for viscosity reduction and fluidization of heavy oil function to reduce viscosity by promoting the emulsification of heavy oil and water, without involving interaction with solid particles. However, the composition and properties of sludge and heavy oil are very different. In particular, sludge contains water and high amounts of solid particles (mud, equipment corrosion products, catalyst powder, coke powder, etc.). The viscosity reduction and fluidization process of sludge must also ensure homogeneity (low water separation rate and no hard sediment).

[0011] Therefore, there is a need to develop a simple, low-cost, safe and reliable method for co-processing oil sludge using gasification to alleviate the environmental pressure caused by oil sludge and improve the utilization rate of oil sludge resources.

[0012] It should be noted that the information disclosed in the foregoing background section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0013] The main objective of this invention is to overcome at least one deficiency of the prior art and provide a method for viscosity reduction and fluidization of oil sludge, which facilitates more convenient co-processing of oil sludge using a coal gasifier, and utilizes the viscosity-reduced fluidized oil sludge with... coal Syngas is produced by co-gasification of basic gasification feedstock, thereby achieving economical and efficient resource utilization and harmless treatment.

[0014] To achieve the above objectives, the first aspect of the present invention provides a method for viscosity reduction and fluidization of oil sludge, the method comprising the following steps:

[0015] Different types of oily sludge are fed into the collection hopper for screening to remove at least some of the impurities in the oily sludge, including but not limited to large stones, bricks and branches.

[0016] The sieved sludge is introduced into a conditioning tank for fluidization conditioning. An aqueous solution of viscosity-reducing fluidizing agent is added in proportion and stirred evenly to obtain homogeneous sludge after viscosity reduction and fluidization.

[0017] This invention utilizes the interfacial activity and synergistic effect of viscosity-reducing fluidizing agents. The viscosity-reducing fluidizing agents are adsorbed at the oil-water, oil-solid, and water-solid interfaces, promoting stable encapsulation between the three phases of oil, water, and solid in oil sludge and suspension and dispersion of solid particles. This enables viscosity reduction, fluidization, and homogenization of various oil sludges with large differences in composition (oil content 0.1-95%, water content 0.01-97%, solid content 3-97%). Ultimately, this ensures that the mixed oil sludge can meet pumping requirements, and that its composition and properties are stable and uniform, with low water separation rate and no hard sedimentation.

[0018] The second aspect of this invention provides a method for co-processing oil sludge using a gasifier. After processing by the method of this invention, the oil sludge is obtained as a homogeneous oil sludge after viscosity reduction and fluidization. The homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the coal-water slurry feed pipe, and simultaneously enters the gasification chamber of the coal-water slurry gasifier through a nozzle along with the coal-water slurry. Alternatively, the homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the pulverized coal feed pipe, and simultaneously enters the gasification chamber of the pulverized coal gasifier through a nozzle along with the pulverized coal. In the gasification chamber, the gasification reaction of the organic matter contained in the oil sludge is completed, ultimately realizing the resource utilization and harmless treatment of the oil sludge.

[0019] The method disclosed in this invention has the following beneficial effects: To reduce the viscosity of oily sludge and enhance its fluidity, the oily sludge is mixed with an aqueous solution of a viscosity-reducing fluidizing agent, promoting a reduction in the viscosity of the oily sludge, improving the fluidity and stability of the oily sludge slurry, allowing the oily sludge to be pumped into the gasifier separately, making the co-gasification reaction of oily sludge with coal-water slurry or pulverized coal simpler, more efficient, and safer and more reliable; various organic matter, including oils, in the oily sludge is converted into syngas under the action of a high-temperature reducing atmosphere, ultimately achieving full resource utilization and thorough harmless treatment of the oily sludge. The oily sludge viscosity-reducing fluidization method and the method of co-processing oily sludge using a gasifier provided by this invention are of great significance for improving resource utilization and protecting the environment. Detailed Implementation

[0020] The present invention will be further described in detail below through embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and do not limit the scope of the invention.

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0023] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on mass, unless being based on mass would not be in accordance with the common understanding of those skilled in the art.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] This invention utilizes the synergistic effect of viscosity-reducing fluidizing agents and stirring to obtain homogeneous oily sludge after viscosity reduction and fluidization. This homogeneous oily sludge can be directly pumped into another pipeline connected in parallel with the coal-water slurry feed pipeline, avoiding direct mixing of the oily sludge and coal-water slurry, which would damage the latter's stability and fluidity, and also avoiding safety and environmental risks. The oily sludge and coal-water slurry then simultaneously enter the gasification chamber of the coal-water slurry gasifier through corresponding annular channels in the nozzles. Under the high-temperature reducing atmosphere in the gasification chamber, the organic matter contained in the oily sludge gasifies, while the inorganic matter contained in the oily sludge and coal gasification ash are discharged from the gasification chamber in a molten state and enter the quench chamber, ultimately being discharged from the gasifier as ash. Furthermore, the homogeneous oily sludge after viscosity reduction and fluidization can also be directly pumped into another pipeline connected in parallel with the pulverized coal feed pipeline, and simultaneously enter the gasification chamber of the pulverized coal gasifier through nozzles, where the gasification reaction of the organic matter contained in the oily sludge is completed.

[0026] Therefore, in one embodiment of the present invention, a method for viscosity reduction and fluidization of sludge is provided, the method comprising the following steps:

[0027] Different types of oily sludge are fed into the collection hopper for screening to remove at least some of the impurities in the oily sludge, including but not limited to large stones, bricks and branches.

[0028] The sieved sludge is introduced into a conditioning tank for fluidization conditioning. An aqueous solution of viscosity-reducing fluidizing agent is added in proportion and stirred evenly to obtain homogeneous sludge after viscosity reduction and fluidization.

[0029] The method for reducing viscosity and fluidizing oily sludge according to the present invention can handle oily sludge in various conditions. In an exemplary embodiment of the present invention, the different types of oily sludge include two or more selected from oil slurry tank bottom sludge, residual oil tank bottom sludge, crude oil tank bottom sludge, sludge from waste oil tank bottom sludge, scum, oil separator bottom sludge, wastewater conditioning tank bottom sludge, and maintenance oily sludge.

[0030] Various technical means can be used to feed oily sludge into the collection hopper for screening. In an exemplary embodiment of the present invention, a screw conveyor or a pump can be used to feed the oily sludge into the collection hopper.

[0031] In an exemplary embodiment of the present invention, a stainless steel screen can be installed at the front end of the hopper to screen the oil sludge, preferably with a screen aperture of 20-50 mm.

[0032] In this invention, the ratio of the viscosity-reducing fluidizing agent aqueous solution to the oil sludge can be selected according to the specific conditions of the oil sludge to facilitate viscosity reduction, fluidization, and homogenization of the oil sludge. In an exemplary embodiment of this invention, adding the viscosity-reducing fluidizing agent aqueous solution in proportion involves mixing the oil sludge and the viscosity-reducing fluidizing agent aqueous solution so that the solids content does not exceed 50 wt%, preferably not more than 40 wt%.

[0033] In an exemplary embodiment of the present invention, in order to fully and uniformly mix the sludge and the aqueous solution of the viscosity reducing fluidizing agent, a stirring paddle can be placed in the conditioning tank, preferably with a double-layer or multi-layer paddle structure, to stir the sludge and the aqueous solution of the viscosity reducing fluidizing agent evenly.

[0034] In an exemplary embodiment of the present invention, a heating coil may be provided in the conditioning tank to maintain the temperature of the mixture of sludge and viscosity-reducing fluidizing agent in the conditioning tank at above 25°C, preferably 25-40°C.

[0035] In an exemplary embodiment of the present invention, the viscosity-reducing fluidizing agent is one or more selected from dodecyl sulfobetaine, alkylphenol polyoxyethylene ether condensate, fatty alcohol polyoxyethylene ether condensate and lignin sulfonate (preferably sodium lignin sulfonate), preferably a mixture of dodecyl sulfobetaine and sodium lignin sulfonate, with a mass concentration ratio of 1:0.2 to 5, preferably 1:0.5 to 2.

[0036] In an exemplary embodiment of the present invention, the amount of the viscosity-reducing fluidizing agent added is 0.5 to 8 wt% of the sludge, preferably 1 to 5 wt%.

[0037] In another embodiment of the present invention, a method for co-processing oil sludge using a gasifier is provided. After being processed by the method of the present invention, the oil sludge is obtained as a homogeneous oil sludge after viscosity reduction and fluidization. The homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the coal-water slurry feed pipe, and simultaneously enters the gasification chamber of the coal-water slurry gasifier through a nozzle along with the coal-water slurry. Alternatively, the homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the pulverized coal feed pipe, and simultaneously enters the gasification chamber of the pulverized coal gasifier through a nozzle along with the pulverized coal. In the gasification chamber, the gasification reaction of the organic matter contained in the oil sludge is completed, ultimately realizing the resource utilization and harmless treatment of the oil sludge.

[0038] In an exemplary embodiment of the present invention, the homogenized sludge and coal-water slurry after viscosity reduction and fluidization are pumped into the fourth and second annular channels of the nozzle (oxygen is introduced into the first and third annular channels of the nozzle) through their respective feed pipes, and then enter the gasification chamber through the nozzle.

[0039] In this invention, the operation of the gasifier is a technique well known to those skilled in the art. The only difference is that, in addition to coal-water slurry, a separately fed, viscosity-reducing fluidized sludge is added as the gasification feedstock. The amount of sludge introduced can be determined based on its source and properties. In an exemplary embodiment of this invention, the gasification chamber temperature of the coal-water slurry gasifier is preferably 1300–1500°C, and the pressure is preferably 2.5–9 MPa; the gasification chamber temperature of the pulverized coal gasifier is preferably 1400–1700°C, and the pressure is preferably 2–4.5 MPa.

[0040] The method provided by the present invention will be further illustrated below through specific embodiments, but this does not limit the present invention.

[0041] The oil sludge used in the examples and comparative examples came from the bottom sludge of oil slurry tanks, residual oil tanks, crude oil tanks, scum, and wastewater conditioning tanks of a refinery. The properties of the oil sludge are shown in Table 1. As can be seen from Table 1, the composition of oil sludge from different sources varies greatly.

[0042] Table 1. Basic Properties of Oil Sludge

[0043]

[0044] Note: * indicates that the scum and sludge at the bottom of the wastewater equalization tank have undergone mechanical dewatering.

[0045] Comparative Example 1

[0046] First, the bottom sludge from the residual oil tank, the bottom sludge from the oil slurry tank, the bottom sludge from the No. 1 crude oil tank, the bottom sludge from the No. 2 crude oil tank, the scum, and the bottom sludge from the sewage conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4wt%). The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50°C was measured using a rotational viscometer (Brookfield DV-II+Pro, USA). The results are shown in Table 2.

[0047] Comparative Example 2

[0048] First, the bottom sludge from the residual oil tank, the bottom sludge from the oil slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, the scum, and the bottom sludge from the wastewater conditioning tank were screened using a 23mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:15:15 (the solids content of the mixture was 14.8 wt%). Next, the mixed sludge was transferred to a conditioning tank, where the temperature was maintained at 30℃. The materials were thoroughly mixed using a double-layered agitator built into the conditioning tank. The mixed sludge was measured at 20℃ and a shear rate of 100 s⁻¹ using a rotational viscometer (NXS-4C model from Chengdu Instrument Factory). -1 The viscosity was measured to be 199.7 mPa·s. Furthermore, to characterize the stability of the mixed sludge, the water separation rates after 5, 15, and 30 days of storage were measured to be 22%, 34%, and 42%, respectively, and the proportions of sediment produced after 5, 15, and 30 days of storage were 7%, 10%, and 11%, respectively.

[0049] Example 1

[0050] First, the bottom sludge from the residual oil tank, the bottom sludge from the oil slurry tank, the bottom sludge from the No. 1 crude oil tank, the bottom sludge from the No. 2 crude oil tank, the scum, and the bottom sludge from the sewage conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4%). The mixed sludge was then introduced into a conditioning tank, and an aqueous solution of alkylphenol polyoxyethylene (20) ether (1 wt% of the sludge) was added. The temperature of the conditioning tank was maintained at 30℃, and the material was stirred evenly using the double-layer stirring paddle built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer (DV-II+Pro type from Brookfield, USA). The results are shown in Table 2.

[0051] Example 2

[0052] First, the bottom sludge from the residual oil tank, the bottom sludge from the oil slurry tank, the bottom sludge from the No. 1 crude oil tank, the bottom sludge from the No. 2 crude oil tank, the scum, and the bottom sludge from the sewage conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (20.4wt% solids content of the mixture). The mixed sludge was then introduced into a conditioning tank, and a fatty alcohol polyoxyethylene (20) ether aqueous solution (1wt% of the sludge) was added. The temperature of the conditioning tank was maintained at 30℃, and the material was stirred evenly using the double-layer stirring paddle built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer (DV-II+Pro type from Brookfield, USA). The results are shown in Table 2.

[0053] Example 3

[0054] First, the bottom sludge from the residual oil tank, the bottom slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (20.4wt% solids content). Next, the mixed sludge was transferred to a conditioning tank, and a dodecyl sulfobetaine aqueous solution (1wt% of the sludge weight) was added. The temperature of the conditioning tank was maintained at 30℃, and the materials were stirred evenly using a double-layer agitator built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer (Brookfield DV-II+Pro). The results are shown in Table 2.

[0055] Example 4

[0056] Add 1% of an aqueous solution of sodium lignosulfonate, otherwise the same as in Example 3.

[0057] First, the bottom sludge from the residual oil tank, the bottom slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4 wt%). Next, the mixed sludge was introduced into a conditioning tank, and a sodium lignosulfonate aqueous solution was added (the amount of sodium lignosulfonate added was 1 wt% of the sludge). The temperature of the conditioning tank was maintained at 30℃, and the materials were stirred evenly using the double-layer stirring paddle built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer (Brookfield DV-II+Pro model, USA). The results are shown in Table 2.

[0058] Example 5

[0059] An aqueous solution of 1% dodecyl sulfobetaine and 1% sodium lignosulfonate was added, otherwise the same as in Example 3. The effect was significantly better than all other examples.

[0060] First, the bottom sludge from the residual oil tank, the bottom slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were screened using a 50mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4 wt%). Next, the mixed sludge was transferred to a conditioning tank, and dodecyl sulfonate aqueous solution and sodium lignosulfonate aqueous solution were added (the amount of dodecyl sulfonate and sodium lignosulfonate added was 1 wt% of the sludge). The temperature of the conditioning tank was maintained at 30℃, and the materials were stirred evenly using the double-layer stirring paddle built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer (Brookfield DV-II+Pro model, USA). The results are shown in Table 2.

[0061] Example 6

[0062] First, the bottom sludge from the residual oil tank, the bottom slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were screened using a 30mm sieve. The screened sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4 wt%). Next, the mixed sludge was transferred to a conditioning tank, and a dodecyl sulfobetaine aqueous solution (dodecyl sulfobetaine was 5 wt% of the sludge) was added. The temperature of the conditioning tank was maintained at 30℃, and the materials were stirred evenly using a double-layer agitator built into the conditioning tank to obtain viscosity-reduced fluidized sludge. The viscosity of the mixed sludge at different rotation speeds at 30, 40, and 50℃ was measured using a rotational viscometer, and the results are shown in Table 2.

[0063] Table 2. Viscosity test results of mixed sludge

[0064]

[0065] Unit: mPa·s

[0066] Example 7

[0067] First, the bottom sludge from the residual oil tank, the bottom sludge from the oil slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were sieved using a 23mm sieve. The sieved sludge was then mixed in a mass ratio of 1:1:4:4:15:15 (14.8wt% solids content). The mixed sludge was then transferred to a conditioning tank, where a 1% aqueous solution of dodecyl sulfobetaine and 1% sodium lignosulfonate was added. The temperature of the conditioning tank was maintained at 30℃. The materials were stirred evenly using a double-layer agitator built into the conditioning tank to obtain a homogeneous sludge with reduced viscosity and fluidization. The viscosity of the homogeneous sludge after reduced viscosity and fluidization was measured using a rotational viscometer (NXS-4C type, Chengdu Instrument Factory) at 20℃ and a shear rate of 100s. -1 The viscosity was measured to be 34.8 mPa·s. In addition, to characterize the stability of the homogenized sludge after viscosity reduction and fluidization, the water separation rates of the sludge after 5 days, 15 days and 30 days of storage were measured to be 0.01%, 0.7% and 0.8%, respectively, and no sediment was generated after 30 days of storage.

[0068] The homogenized oil sludge after viscosity reduction and fluidization was fed to coal-water slurry at a mass ratio of 5:100. The oil sludge and coal-water slurry were pumped into the fourth and second annular channels of the nozzle (oxygen was introduced into the first and third annular channels of the nozzle) through their respective feed pipelines, and then entered the gasification chamber of the gasifier through the nozzle. The gasification chamber temperature was 1350℃, the gasification pressure was 6.5MPa, the feed carbon conversion rate was 98.5%, and the dry basis effective gas (CO+H2) was 79% (by volume). The gasifier operated stably.

[0069] Example 8

[0070] First, the bottom sludge from the residual oil tank, the bottom slurry tank, the bottom sludge from crude oil tank #1, the bottom sludge from crude oil tank #2, scum, and the bottom sludge from the wastewater conditioning tank were sieved using a 23mm sieve. The sieved sludge was then mixed in a mass ratio of 1:1:4:4:7:7 (the solid content of the mixture was 20.4wt%). Next, the mixed sludge was transferred to a conditioning tank, and an aqueous solution of 1% dodecyl sulfobetaine and 1% sodium lignosulfonate was added. The temperature of the conditioning tank was maintained at 20℃, and the materials were stirred evenly using the double-layer stirring paddle built into the conditioning tank to obtain homogeneous sludge after viscosity reduction and fluidization. The viscosity of the mixed sludge at 20℃ and a shear rate of 100s⁻¹ was measured using a rotational viscometer (NXS-4C type, Chengdu Instrument Factory). -1 The viscosity was measured to be 125.7 mPa·s. Furthermore, to characterize the stability of the mixed sludge, the water separation rates after 5, 15, and 30 days of storage were measured to be 0.01%, 0.6%, and 0.8%, respectively, with no sediment formation after 30 days of storage.

[0071] The homogenized oil sludge after viscosity reduction and fluidization was fed to pulverized coal at a mass ratio of 10:100. The oil sludge and coal-water slurry were pumped into the gasification chamber of the gasifier through their respective feed pipelines and nozzles. The gasification chamber temperature was 1600℃, and the gasification pressure was 3.5MPa. The carbon conversion rate of the feedstock was 98.2%, and the effective gas (CO+H2) on a dry basis was 85% (by volume). The gasifier operated stably.

[0072] As demonstrated in Examples 1-8 and Comparative Examples 1-2, the viscosity-reducing fluidization method of the present invention utilizes a viscosity-reducing fluidizing agent to mix with different types of oily sludge, thereby reducing the viscosity of the mixed oily sludge and improving its fluidity and stability. This allows the viscosity-reduced, fluidized, and homogenized oily sludge to be pumped into a gasifier for coal-water slurry or pulverized coal. The organic matter in the oily sludge is converted into syngas under the high temperature and reducing atmosphere of the gasification chamber. This method achieves the co-processing of oily sludge and the production of syngas using a gasifier, and is characterized by its simple process, low cost, and safety and reliability.

[0073] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this invention. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0074] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A method for reducing the viscosity of oil sludge through fluidization, characterized in that, Includes the following steps: Different types of oily sludge are fed into the collection hopper for screening to remove impurities from the oily sludge, including but not limited to large stones, bricks and branches. The screened sludge is introduced into a conditioning tank for fluidized conditioning. An aqueous solution of viscosity reducing fluidizing agent is added in proportion and stirred evenly to obtain homogeneous sludge after viscosity reduction fluidization. The different types of sludge are selected from two or more of the following: bottom sludge of oil slurry tank, bottom sludge of residual oil tank, bottom sludge of crude oil tank, bottom sludge of sludge tank, scum, bottom sludge of oil separator, bottom sludge of sewage regulating tank, and maintenance sludge. The viscosity-reducing fluidizing agent is a mixture of dodecyl sulfobetaine and sodium lignosulfonate, with a mass concentration ratio of 1:0.2~5, and the amount of the viscosity-reducing fluidizing agent added is 1~5 wt% of the sludge.

2. The method as described in claim 1, characterized in that, Use a screw conveyor or pump to feed the sludge into the collection hopper.

3. The method as described in claim 1, characterized in that, A stainless steel screen is installed at the front end of the hopper to screen the oil sludge.

4. The method as described in claim 3, characterized in that, The mesh size of the screen is 20 to 50 mm.

5. The method as described in claim 1, characterized in that, The aqueous solution of the viscosity reducing fluidizing agent added in proportion includes mixing the sludge with the aqueous solution of the viscosity reducing fluidizing agent, such that the solid content does not exceed 50 wt%.

6. The method as described in claim 5, characterized in that, The solids content shall not exceed 40 wt%.

7. The method as described in claim 1, characterized in that, The conditioning tank is equipped with a stirring paddle for mixing the sludge and the aqueous solution of the viscosity reducing fluidizing agent evenly.

8. The method as described in claim 7, characterized in that, The stirring paddle has a double-layer or multi-layer blade structure.

9. The method as described in claim 1, characterized in that, The conditioning tank is equipped with a heating coil to maintain the temperature of the sludge inside the conditioning tank at above 25°C.

10. The method as described in claim 9, characterized in that, The temperature is maintained at 25~40℃.

11. The method as described in claim 1, characterized in that, The mass concentration ratio of dodecyl sulfobetaine to sodium lignosulfonate is 1:0.5~2.

12. A method for co-processing oily sludge using a gasifier, characterized in that, After being treated by the method described in any one of claims 1 to 11, the oil sludge is obtained as a homogeneous oil sludge after viscosity reduction and fluidization. The homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the coal-water slurry feed pipe, and simultaneously enters the gasification chamber of the coal-water slurry gasifier through a nozzle along with the coal-water slurry. Alternatively, the homogeneous oil sludge after viscosity reduction and fluidization is pumped into another pipe connected in parallel with the pulverized coal feed pipe, and then simultaneously enters the gasification chamber of the pulverized coal gasifier through a nozzle along with the pulverized coal. The gasification reaction of the oil sludge is completed in the gasification chamber, ultimately realizing the resource utilization and harmless treatment of the oil sludge.

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