A device and method for deep dechlorination and demetallization of waste bio-oil

Abstract

The invention discloses a device and method for deep dechlorination and demetallization of waste bio-oil, comprising a horizontal tank body, an acid injection, mixing and strengthening washing module, an acid droplet internal circulation deep extraction module and a fiber coagulation acid-water separation module which are sequentially arranged inside the horizontal tank body according to the flow direction of the waste bio-oil; the device is an integrated device integrating acid injection, washing, extraction and aggregation and separation; after the acid droplets are micro-dispersed and emulsified into the waste bio-oil, a washing core tube is used to strengthen the two-phase mixing to achieve the preliminary elution of chlorine and heavy metals; hydrophilic and oleophobic fiber modules of the same material with different cross-sectional areas are combined in series; a small-area hydrophilic and oleophobic fiber module is built in the acid droplet internal circulation deep extraction module with a Venturi structure to achieve the acid droplet internal circulation deep extraction of chlorine and heavy metals; and then a large-area hydrophilic and oleophobic fiber module is used to achieve the aggregation of fine acid droplets to strengthen oil-water separation; the treatment process is greatly shortened, the energy consumption is low, the purification efficiency is high, and it is easy to promote in industry.

Description

Technical Field

[0001] The invention belongs to the technical field of waste bio-oil impurity removal, and in particular relates to a device and method for deep dechlorination and demetallization of waste bio-oil. Background Art

[0002] Waste bio-oil (including but not limited to waste cooking oil) is a recyclable resource. After chemical and physical transformation or physical refining, it can be turned into treasure, generating considerable economic and social benefits. Almost all of the current official production capacity adopts the oil hydrogenation (HEFA) route. According to forecasts from different institutions, due to the immature technology of other routes and high production costs, oil hydrogenation will still be dominant before 2030. Waste bio-oil is pretreated, hydrogenated, hydrogenated and fractionated to finally make bio-jet fuel. Using waste bio-oil as raw material to produce bio-jet fuel is not only cheap and easy to obtain, but also very beneficial to the comprehensive management of waste bio-oil, and the economic benefits are also very considerable.

[0003] The main components of waste bio-oil are waste cooking oil and animal fat, etc. It has a high viscosity at room temperature and good fluidity after being heated to 80-90°C. However, due to the addition of chemical additives in the food processing industry and various condiments in the catering industry, waste bio-oil contains a large amount of water-soluble heavy metals and chloride salts, which leads to the deactivation and poisoning of catalysts in the subsequent processing and production of bio-jet fuel, and ultimately results in short operating cycles, substandard product quality, high energy consumption, and even the inability to obtain products, which greatly restricts the comprehensive utilization of waste bio-oil.

[0004] Currently, the most common desalination method is to inject hot water into waste cooking oil for mixed washing, so that the water-soluble metal salts in the waste cooking oil are dissolved or dispersed in the water, and then the water is removed by oil-water separation to achieve the purpose of removing salt from the oil. However, the existing technology usually directly injects a certain amount of hot water into the oil storage tank, and applies mechanical stirring to enhance the mixing of the oil and water phases. The mixed oil and water phases are directly separated by centrifugation, which causes high noise and power consumption, and is difficult to maintain. At the same time, the oil-water separation effect is poor, and the waste bio-oil will carry water with a high water content. It also requires additional drying (vacuum dryer) treatment, which is cumbersome to operate and has high energy consumption. In response to the above technical difficulties, some solutions have been found in the existing technology:

[0005] CN113088401A discloses a system for pre-treating waste kitchen grease, which includes a waste kitchen grease storage tank, a heating and stirring tank, an oil-water mixer, an ultrasonic demulsification tank, an oil-water separator and a desulfurization tower. The outlet of the waste kitchen grease storage tank is connected to the inlet of the heating and stirring tank through a pipeline; a hot water inlet is provided on the top of the oil-water mixer, and the hot water inlet is connected to a hot water pipe, and the outlet of the heating and stirring tank is connected to the inlet of the oil-water mixer through a pipeline; the outlet of the oil-water mixer is connected to the inlet of the ultrasonic demulsification tank through a pipeline; an oil discharge port is provided on the upper part of the oil-water separator, and the outlet of the ultrasonic demulsification tank is connected to the inlet of the oil-water separator through a pipeline. The invention has a simple structure, stable operation and convenient maintenance.

[0006] However, this pretreatment system still has the following defects:

[0007] (1) The industrial application of ultrasonic demulsification requires high investment and requires frequent shutdown for maintenance, resulting in high maintenance costs. (2) The process treatment effect is not good. The pretreatment requirements may not be met by only one-way cyclone mixing + ultrasonic demulsification + agglomeration oil-water separation. Additional series treatment units will further increase investment costs and energy consumption is also high. Summary of the invention

[0008] Aiming at the problem that the heavy metal and chlorine contents in waste bio-oil are too high, which causes poisoning and deactivation of subsequent hydrogenation reaction catalysts, the present invention proposes a device and method for deep dechlorination and demetallization of waste bio-oil.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of the present invention is to provide a device for deep dechlorination and demetallization of waste bio-oil, comprising a horizontal tank body, an acid injection and mixing enhanced washing module, an acid droplet internal circulation deep extraction module and a fiber coagulation acid-water separation module sequentially arranged inside the horizontal tank body according to the flow direction of the waste bio-oil; wherein:

[0011] The horizontal tank body is provided with a feed pipe, an oil discharge port and a water bag;

[0012] The acid injection and mixing enhanced washing module comprises a micro-acid droplet generator and a liquid distributor connected to the feed pipe in sequence, and a plurality of washing core tubes connected to the tail end of the liquid distributor; the micro-acid droplet generator is used to generate micro-acid droplets, and the washing core tube is used to enhance the turbulent mixing between the acid droplets and the waste bio-oil;

[0013] The acid droplet internal circulation deep extraction module comprises a fluid speed-up section with a gradually decreasing cross-sectional area, an internal circulation extraction section with a constant cross-sectional diameter, and a buffer section with a gradually increasing cross-sectional area, which are connected in sequence. The internal circulation extraction section is composed of a hydrophilic and oleophobic fiber module.

[0014] The fiber coagulation acid-water separation module is composed of a hydrophilic and oleophobic fiber module.

[0015] The present invention is further configured that the washing core tube includes a spinning section and a voltage transformation section, wherein:

[0016] The front end of the rotating section is connected to the rear end of the liquid distributor; the rotating section includes a cylinder, a support rod located at the axis of the cylinder, and a spiral blade arranged around the support rod, and the spiral blade includes a right-handed blade and a left-handed blade connected from front to back;

[0017] The helical angle α of the helical blade is 35-45°.

[0018] The present invention is further configured such that the transformer section includes a swirl buffer zone, a transformer oscillation zone and a transformer buffer zone which are connected in sequence, the transformer oscillation zone is a Venturi structure whose cross-sectional area changes continuously from gradually contracting, equal diameter to gradually expanding, and the swirl buffer zone of the transformer section is connected to the tail end of the swirl section;

[0019] The length ratio of the rotation section to the transformer section is 3:2-1:1, and the area ratio of the maximum cross section to the minimum cross section of the transformer section is 3:1-2:1.

[0020] The present invention is further configured such that the hydrophilic and oleophobic fiber modules in the internal circulation extraction section and the fiber coagulation and acid-water separation module are both acid-resistant and corrosion-resistant fiber modules, and the fiber modules are built with multiple groups of parallel-arranged hydrophilic and oleophobic fibers;

[0021] The hydrophilic and oleophobic fiber modules are woven in an X-shaped manner, with a porosity of 0.7-0.8 and a fiber diameter of 100-200 μm;

[0022] The hydrophilic and oleophobic fiber module is made of polyethyleneimine and fluorine-containing materials;

[0023] The cross-sectional area ratio of the hydrophilic and oleophobic fiber modules of the acid droplet internal circulation deep extraction module and the fiber coagulation acid-water separation module is 0.7-0.8.

[0024] The present invention is further configured such that the cross-sectional area of ​​the internal circulation extraction section in the acid drop internal circulation deep extraction module is 0.7-0.8 times the cross-sectional area of ​​the horizontal tank body;

[0025] The ratio of the overall length of the fiber coagulation acid-water separation module to the overall length of the acid droplet internal circulation deep extraction module is 1:1-2:3.

[0026] The present invention is further configured such that the device further comprises a flow stabilizing module, and the flow stabilizing module comprises rectifier plates arranged at the front and rear sides of the acid droplet inner circulation deep extraction module.

[0027] The second aspect of the present invention provides a method for deep dechlorination and demetallization of waste bio-oil based on the above device, comprising the following steps:

[0028] (I) Preliminary elution: fine acid droplets are generated by a micro-acid droplet generator and uniformly emulsified into the waste bio-oil to obtain acid-containing waste bio-oil, which is then uniformly injected into the washing core tube through a liquid distributor to enhance the mixing of the acid droplets and the oil phase, thereby achieving preliminary elution of chlorine and heavy metals;

[0029] (II) Deep elution: After the initial elution, the acid-containing waste bio-oil enters the Venturi-type acid droplet internal circulation deep extraction module, and after initial acceleration, it enters the internal circulation extraction section. The acid droplets adhere to the hydrophilic and oleophobic fiber module. Under the action of the strong shear force of the external fluid, a horseshoe-shaped symmetrical cross-flow zone is formed on both sides of the acid droplets, and internal circulation occurs to capture chlorine and heavy metals in the oil phase; at the same time, the internal circulation accelerates the renewal of the acid droplet surface, thereby strengthening the convective mass transfer extraction of chlorine and heavy metals on the basis of diffusion mass transfer, and finally achieving deep elution of chlorine and heavy metals;

[0030] (III) Acid-water separation: After deep elution, the acid-containing waste bio-oil enters the fiber coagulation acid-water separation module. The fine acid droplets are captured, aggregated, and grown into large acid droplets on the hydrophilic and oleophobic fiber modules. They are finally separated from the water bag at the bottom of the horizontal tank. The purified bio-oil is sent to the downstream from the oil discharge port.

[0031] The present invention is further configured that, in step (I), the ratio of acid injection in the waste bio-oil is determined according to the metal content in the imported waste bio-oil, specifically as follows:

[0032] (a) If the total metal content of the imported waste bio-oil is within 100 ppm, the acid injection volume shall be within 5% of the total volume of the oil phase;

[0033] (b) If the total metal content of the imported waste bio-oil is between 100-500 ppm, the acid injection amount is 6-8% of the total volume of the oil phase;

[0034] (c) If the total metal content of the imported waste bio-oil is between 500-1000 ppm, the acid injection volume is 8-10% of the total volume of the oil phase;

[0035] The present invention is further configured that the fine acid droplets are organic acids, the concentration of the organic acids is 0.5-1wt%; the organic acid is oxalic acid or citric acid;

[0036] The size of the fine acid droplets generated by the micro-acid droplet generator is 50-200 μm.

[0037] The present invention is further configured such that the temperature of the waste bio-oil entering the horizontal tank body needs to be controlled at 90-110°C; the cross-sectional flow velocity of the waste bio-oil when entering the acid droplet inner circulation deep extraction module is controlled at 0.01-0.015m / s; and the cross-sectional flow velocity of the waste bio-oil when entering the fiber coagulation acid-water separation module is controlled at 0.003-0.005m / s.

[0038] The beneficial effects of the present invention are as follows:

[0039] 1. The device for deep dechlorination and demetallization of waste bio-oil of the present invention is an integrated device integrating acid injection, washing, extraction and aggregation and separation. After the acid droplets are micro-dispersed and emulsified into the waste bio-oil, the washing core tube is used to strengthen the mixing of the two phases to achieve the preliminary elution of chlorine and heavy metals, and hydrophilic oleophobic fiber modules of the same material with different cross-sectional areas are combined in series. The small-area hydrophilic oleophobic fiber module is built in the acid droplet inner circulation deep extraction module of the Venturi structure to achieve the acid droplet inner circulation deep extraction of chlorine and heavy metals, and then the large-area hydrophilic oleophobic fiber module is used to achieve the aggregation of fine acid droplets to strengthen oil-water separation.

[0040] 2. The present invention is based on the principle of deep metal complexation in the acid droplets adhering to the fiber. By reasonably controlling the relative flow rate of the waste bio-oil and the acid droplets, the laminar strong shear force is applied to the acid droplets captured on the fiber, thereby accelerating the interface renewal of the acid droplet surface, and strengthening the convection mass transfer on the basis of diffusion mass transfer to further extract chlorine and heavy metals, and finally achieving deep elution of chlorine and heavy metals. The device can reduce the heavy metal content in the waste bio-oil from 1000ppm+ to 10-30ppm, with the advantages of low cost, high efficiency, green and high efficiency.

[0041] 3. The main modules of the present invention are in the form of internal components, and can be directly modified in the original horizontal oil-water separator or filter without re-processing a new separator. The construction is simple, cost and land saving, and the economic benefit is high. Compared with the traditional demetallization process of multiple acid and alkali stirring and washing at home and abroad, the present invention greatly shortens the treatment process and reduces energy consumption, has low investment cost, compact structure, small amount of waste liquid generated, high purification efficiency, and is easy to promote in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the structure of the device for deep dechlorination and demetallization of waste bio-oil of the present invention.

[0043] Figure 2 It is a connection diagram of the micro-acid droplet generator, the liquid distributor and the washing core tube.

[0044] Figure 3 It is a structural schematic diagram of the washing core tube.

[0045] Figure 4 It is a structural schematic diagram of the rotation section.

[0046] Figure 5 It is a structural diagram of the transformer section.

[0047] Figure 6 It is a schematic diagram of the flow process of metal salt and organic acid after the flow rate is increased when the acid droplets adhere to the fiber.

[0048] Figure 7 This is the schematic diagram of the internal circulation of acid drops.

[0049] Figure 8 It is a structural schematic diagram of the existing waste bio-oil dechlorination and demetallization equipment.

[0050] in:

[0051] 1-horizontal tank; 11-feed pipe; 12-oil outlet; 13-water bag;

[0052] 2-acid injection and mixing enhanced washing module, 21-micro-acid droplet generator, 22-liquid distributor, 221-main pipe; 222-distribution pipe; 23-washing core pipe; 231-spinning section; 232-voltage transformation section; 233-cylinder; 234-support rod; 235-spiral blade; 236-spinning buffer zone; 237-voltage transformation oscillation zone; 238-voltage transformation buffer zone;

[0053] 3-acid drop internal circulation deep extraction module; 31-fluid speed-up section; 32-internal circulation extraction section; 33-buffer section;

[0054] 4-Fiber coagulation acid water separation module;

[0055] 5-rectifier plate;

[0056] 6-waste bio-oil dechlorination and demetallization equipment; 61-tank body; 62-emulsifier; 63-guide plate; 64-coalescing module; 65-inlet pipe; 66-oil phase outlet; 67-water phase outlet. DETAILED DESCRIPTION

[0057] The technical solution of the present invention will be clearly and completely described below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of the present invention.

[0058] The micro-acid droplet generator 21 in the following embodiments is a conventional device in the art, and the orientations "front" and "back" used are determined by the flow direction of the waste bio-oil.

[0059] Research has found that after deacidification, decolorization and deodorization, waste bio-oil still contains high levels of heavy metals such as potassium, calcium and sodium, as well as chloride salts. These heavy metals and chloride salts will cause severe deactivation of the catalyst in the subsequent esterification and hydrogenation reaction of waste bio-oil. Therefore, it is necessary to carry out deep dechlorination and demetallization treatment of waste bio-oil.

[0060] Example 1

[0061] Figure 1 The device for deep dechlorination and demetallization of waste bio-oil of the present invention is shown. As can be seen from the figure, the device for deep dechlorination and demetallization of waste bio-oil of the present invention comprises a horizontal tank body 1, an acid injection and mixing enhanced washing module 2, an acid droplet internal circulation deep extraction module 3 and a fiber coagulation acid-water separation module 4 which are sequentially arranged inside the horizontal tank body 1 according to the flow direction of the waste bio-oil; wherein:

[0062] The horizontal tank body 1 is provided with a feed pipe 11, an oil discharge port 12 and a water bag 13;

[0063] Waste bio-oil enters the tank through the feed pipe 11, and after deep dechlorination and demetallization, it is discharged from the horizontal tank body 1 through the oil discharge port 12 and enters the downstream treatment.

[0064] Combination Figure 2 As shown, the acid injection and mixing enhanced washing module 2 includes a micro-acid droplet generator 21 and a liquid distributor 22 connected to the feed pipe 11 in sequence, and a plurality of washing core tubes 23 connected to the tail end of the liquid distributor 22;

[0065] The micro-acid droplet generator 21 is used to generate micro-acid droplets and evenly emulsify the acid droplets into the waste bio-oil to form acid-containing waste bio-oil. The liquid distributor 22 is used to evenly distribute the acid-containing waste bio-oil to each washing core tube 23. The washing core tube 23 is used to strengthen the turbulent mixing between the acid droplets and the waste bio-oil.

[0066] Back to Figure 1 The acid droplet inner circulation deep extraction module 3 is a Venturi structure with a built-in hydrophilic oleophobic fiber module, including a fluid speed-up section 31 with a gradually shrinking cross-sectional area, an inner circulation extraction section 32 with a constant cross-sectional diameter, and a buffer section 33 with a gradually expanding cross-sectional area, which are connected in sequence. The inner circulation extraction section 32 is composed of a hydrophilic oleophobic fiber module, which is convenient for the acid droplets to adhere to and stabilize on the hydrophilic oleophobic fiber module;

[0067] The fluid speed-up section 31 is used to provide sufficient shear kinetic energy for the waste bio-oil; the buffer section 33 is used to reduce the flow rate, which is beneficial to the subsequent acid-water separation in the fiber coagulation acid-water separation module 4.

[0068] The fiber coagulation acid-water separation module 4 is composed of a hydrophilic and oleophobic fiber module, which is used to aggregate the fine acid droplets after washing and extracting chlorine and heavy metals into large acid droplets, which finally fall off the fibers and gather in the water bag 13 at the bottom of the horizontal tank 1 for separation.

[0069] In this embodiment, Figure 2 As shown, the liquid distributor 22 includes a main pipe 221 whose head end is connected to the feed pipe 11, and a plurality of distribution pipes 222 connected to the tail end of the main pipe 221, and the number of the distribution pipes 222 is 4-6.

[0070] In this embodiment, Figure 3 As shown, the washing core tube 23 includes a rotation section 231 and a voltage transformation section 232, wherein:

[0071] Combination Figure 4 As shown, the front end of the swirling section 231 is connected to the distribution pipe 222 of the liquid distributor 22; the swirling section 231 includes a cylinder 233, a support rod 234 located at the axis of the cylinder 233, and a spiral blade 235 arranged around the support rod 234, the spiral blade 235 includes a right-handed blade and a left-handed blade connected from front to back, which are used for swirling to enhance the mixing of acid droplets and oil phase, and the spiral angle α of the spiral blade 235 is 35-45°.

[0072] The pressure changing section 232 is used for breaking and shaking the acid droplets and the oil phase, strengthening the two-phase turbulent emulsification, and combining Figure 5 As shown, it includes a swirl buffer zone 236, a voltage-changing oscillation zone 237 and a voltage-changing buffer zone 238 which are connected in sequence. The voltage-changing oscillation zone 237 is a Venturi-type structure whose cross-sectional area changes continuously from gradually contracting, equal diameter to gradually expanding. The swirl buffer zone 236 of the voltage-changing section 232 is connected to the tail end of the swirl section 231.

[0073] After the acid-containing waste bio-oil after swirl mixing from the swirl section 231 enters the pressure transformation section 232, it is first buffered in the swirl buffer area 236, and then in the pressure transformation oscillation zone 237, pressure is generated due to the reduction of the cross-sectional area, thereby producing oscillation emulsification, and finally enters the next module after being buffered in the pressure transformation buffer area 238.

[0074] Preferably, the length ratio of the rotation section 231 to the voltage transformation section 232 is 3:2-1:1, and the area ratio of the maximum cross section to the minimum cross section of the voltage transformation section 232 is 3:1-2:1.

[0075] Furthermore, the hydrophilic and oleophobic fiber module is an acid-resistant and corrosion-resistant fiber module, and the fiber module has multiple groups of parallel-arranged hydrophilic and oleophobic fibers built therein;

[0076] Preferably, the hydrophilic and oleophobic fiber modules are woven in an X-shaped manner, with a porosity of 0.7-0.8 and a fiber diameter of 100-200 μm.

[0077] Preferably, the hydrophilic and oleophobic fiber module is made by mixing polyethyleneimine and fluorine-containing material.

[0078] Preferably, the cross-sectional area ratio of the hydrophilic and oleophobic fiber modules of the internal circulation extraction section 32 and the fiber coagulation acid-water separation module 4 is 0.7-0.8.

[0079] Further, the cross-sectional area of ​​the internal circulation extraction section 32 in the acid drop internal circulation deep extraction module 3 is 0.7-0.8 times the cross-sectional area of ​​the horizontal tank body 1;

[0080] The ratio of the overall length of the fiber coagulation acid-water separation module 4 to the overall length of the acid droplet internal circulation deep extraction module 3 is 1:1-2:3.

[0081] like Figure 6 and Figure 7 As shown, the acid-containing waste bio-oil treated by the acid injection mixed enhanced washing module 2 enters the acid droplet inner circulation deep extraction module 3, and enters the inner circulation extraction section 32 after the fluid speed-up section 31 initially increases the flow rate. The acid droplets in the acid-containing waste bio-oil are adsorbed by the hydrophilic and oleophobic fibers of the inner circulation extraction section 32. Under the action of the strong shear force of the external fluid (oil phase), a horseshoe-shaped symmetrical cross-flow zone is formed on both sides of the acid droplet, and an inner circulation flow occurs. The surface of the acid droplet captures chlorine and heavy metals until saturation. At the same time, the inner circulation accelerates the surface renewal of the acid droplet, thereby strengthening the convective mass transfer extraction of metal ions and chloride ions on the basis of diffusion mass transfer, and realizing the deep elution of heavy metals and chloride salts.

[0082] As time goes by, the acid droplets are intercepted by the hydrophilic oleophobic fibers, continuously aggregate and grow, and at the same time continuously capture new chlorine and heavy metals. Finally, under the action of gravity and external fluid impact, the acid droplets enriched with chlorine and heavy metals fall off the hydrophilic oleophobic fibers. Then, along with the waste bio-oil, they enter the fiber coagulation acid-water separation module 4, where the fine acid droplets are captured by the hydrophilic oleophobic fibers, gradually aggregate and grow into large acid droplets, and finally separate from the water bag 13 at the bottom of the device, and the purified waste bio-oil is sent to the downstream from the oil discharge port 12.

[0083] Furthermore, the device further comprises a flow stabilizing module (not marked in the figure), which comprises a rectifier plate 5 (see FIG. 1 ) arranged at the front and rear sides of the acid droplet inner circulation deep extraction module 3. Figure 1 ), which is used to control the flow rate of the acid-containing waste bio-oil so that it can enter the acid droplet inner circulation deep extraction module 3 and the fiber coagulation acid-water separation module 4 more evenly to improve the separation effect.

[0084] A method for deep dechlorination and demetallization of waste bio-oil based on the above device comprises the following steps:

[0085] (I) Preliminary elution: fine acid droplets are generated by a micro-acid droplet generator 21 and are uniformly emulsified into the waste bio-oil to obtain acid-containing waste bio-oil, which is then uniformly injected into the washing core tube 23 through a liquid distributor 22 to enhance the mixing of the acid droplets and the oil phase, thereby achieving preliminary elution of chlorine and heavy metals;

[0086] (II) Deep elution: After the initial elution, the acid-containing waste bio-oil enters the acid droplet inner circulation deep extraction module 3, and after the initial acceleration, enters the inner circulation extraction section 32. The acid droplets adhere to the hydrophilic and oleophobic fiber module. Under the action of the strong shear force of the external fluid, a horseshoe-shaped symmetrical cross-flow zone is formed on both sides of the acid droplets, and an internal circulation occurs to capture chlorine and heavy metals in the oil phase; at the same time, the internal circulation accelerates the renewal of the acid droplet surface, thereby strengthening the convective mass transfer extraction of metal ions on the basis of diffusion mass transfer, and finally achieving deep elution of chlorine and heavy metals;

[0087] (III) Acid-water separation: After deep elution, the acid-containing waste bio-oil enters the fiber coagulation acid-water separation module 4, where the fine acid droplets are captured, aggregated, and grown into large acid droplets on the hydrophilic and oleophobic fiber modules, and finally separated from the water bag 13 at the bottom of the horizontal tank 1. The purified bio-oil is sent to the downstream from the oil discharge port 12.

[0088] Furthermore, in step (I), the ratio of acid injection in the waste bio-oil is determined according to the metal content in the imported waste bio-oil, as follows:

[0089] (a) If the total metal content of the imported waste bio-oil is within 100 ppm, the acid injection volume shall be within 5% of the total volume of the oil phase;

[0090] (b) If the total metal content of the imported waste bio-oil is between 100-500 ppm, the acid injection amount is 6-8% of the total volume of the oil phase;

[0091] (c) If the total metal content of the imported waste bio-oil is between 500-1000 ppm, the acid injection amount is 8-10% of the total volume of the oil phase.

[0092] Considering the demetallization efficiency and economic cost, in step (I), the fine acid droplets are organic acids, preferably oxalic acid or citric acid, and the concentration of the organic acid is 0.5-1wt%;

[0093] The size of the fine acid droplets generated by the fine acid droplet generator 21 is 50-200 μm.

[0094] Furthermore, the temperature of the waste bio-oil entering the horizontal tank 1 is 90-110°C; the cross-sectional flow rate of the waste bio-oil entering the acid droplet inner circulation deep extraction module 3 is controlled at 0.01-0.015m / s; the cross-sectional flow rate of the waste bio-oil entering the fiber coagulation acid-water separation module 4 is controlled at 0.003-0.005m / s.

[0095] Application Examples

[0096] like Figure 8 As shown, at present, some environmental protection companies use a conventional waste bio-oil dechlorination and demetallization device 6 that integrates emulsification, rectification, agglomeration and separation, which includes a tank body 61, an emulsifier 62, a guide plate 63 and agglomeration module 64 arranged in sequence inside the tank body 61, and an inlet pipe 65 connected to the emulsifier 62, and an oil phase outlet 66 and a water phase outlet 67 arranged on the tank body 61; the device injects water into the waste bio-oil through the emulsifier 62 to disperse and emulsify it, and then absorbs chlorine and heavy metals in the waste bio-oil through the agglomeration module 64 to achieve the purpose of removal.

[0097] An environmental protection company uses the waste bio-oil deep dechlorination and demetallization device of Example 1 to dechlorinate and demetallize waste bio-oil. Figure 8 The original waste bio-oil dechlorination and demetallization equipment shown in the figure was used as a comparative example, and two tests were carried out. The reaction environment conditions of the tests and the product properties before and after treatment are shown in Table 1.

[0098] Table 1

[0099]

[0100] It can be seen from the results in Table 1 that in Test 1, the demetallization efficiency of the device for deep dechlorination and demetallization of waste bio-oil of the present invention was increased by 45% and the dechlorination efficiency was increased by 65% ​​compared with the original device. In Test 2, the demetallization efficiency of the device for deep dechlorination and demetallization of waste bio-oil of the present invention was increased by 18% and the dechlorination efficiency was increased by 65% ​​compared with the original device. It can be seen that the device of the present invention can achieve deep dechlorination and demetallization, which greatly improves the demetallization efficiency and dechlorination efficiency compared with the original equipment, and the higher the metal content in the waste bio-oil, the more significant the demetallization efficiency improvement effect.

[0101] The principles and implementation methods of the present invention are described above through specific examples. The above embodiments are only used to help understand the method and core ideas of the present invention, so that ordinary technicians in the field can implement or use the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A device for deep dechlorination and demetallization of waste bio-oil, characterized in that: The invention comprises a horizontal tank body (1), an acid injection mixing enhanced washing module (2) arranged in sequence inside the horizontal tank body (1) according to the flow direction of the waste bio-oil, an acid droplet internal circulation deep extraction module (3) and a fiber coagulation acid-water separation module (4); wherein: The horizontal tank body (1) is provided with a feed pipe (11), an oil discharge port (12) and a water bag (13); The acid injection and mixing enhanced washing module (2) comprises a micro-acid droplet generator (21) and a liquid distributor (22) connected to the feed pipe (11) in sequence, and a plurality of washing core tubes (23) connected to the tail end of the liquid distributor (22); the micro-acid droplet generator (21) is used to generate micro-acid droplets, and the washing core tubes (23) are used to enhance the turbulent mixing between the acid droplets and the waste bio-oil; The acid droplet internal circulation deep extraction module (3) comprises a fluid speed-up section (31) with a gradually decreasing cross-sectional area, an internal circulation extraction section (32) with a constant cross-sectional diameter, and a buffer section (33) with a gradually increasing cross-sectional area, which are connected in sequence; the internal circulation extraction section (32) is composed of a hydrophilic and oleophobic fiber module; The fiber coagulation acid-water separation module (4) is composed of a hydrophilic and oleophobic fiber module; The device further comprises a flow stabilization module, which comprises rectifier plates (5) arranged at the front and rear sides of the acid droplet inner circulation deep extraction module (3).

2. The device for deep dechlorination and demetallization of waste bio-oil according to claim 1, characterized in that: The washing core tube (23) comprises a spinning section (231) and a voltage transformation section (232), wherein: The front end of the rotating section (231) is connected to the rear end of the liquid distributor (22); the rotating section (231) comprises a cylinder (233), a support rod (234) located at the axis of the cylinder (233), and a spiral blade (235) arranged around the support rod (234), and the spiral blade (235) comprises a right-handed blade and a left-handed blade connected from front to back; The helical angle α of the helical blade (235) is 35-45°.

3. The device for deep dechlorination and demetallization of waste bio-oil according to claim 2, characterized in that: The voltage transformation section (232) comprises a swirl buffer zone (236), a voltage transformation oscillation zone (237) and a voltage transformation buffer zone (238) which are connected in sequence; the voltage transformation oscillation zone (237) is a Venturi-type structure whose cross-sectional area changes continuously from gradually contracting, constant diameter to gradually expanding; the swirl buffer zone (236) of the voltage transformation section (232) is connected to the tail end of the swirl section (231); The ratio of the length of the rotation section (231) to the voltage transformation section (232) is 3:2-1:1, and the ratio of the area of ​​the maximum cross section to the minimum cross section of the voltage transformation section (232) is 3:1-2:

1.

4. The device for deep dechlorination and demetallization of waste bio-oil according to claim 1, characterized in that: The hydrophilic and oleophobic fiber modules in the internal circulation extraction section (32) and the fiber coagulation and acid-water separation module (4) are both acid-resistant and corrosion-resistant fiber modules, and the fiber modules are built with multiple groups of parallel-arranged hydrophilic and oleophobic fibers; The hydrophilic and oleophobic fiber modules are woven in an X-shaped manner, with a porosity of 0.7-0.8 and a fiber diameter of 100-200 μm; The hydrophilic and oleophobic fiber module is made of polyethyleneimine and fluorine-containing materials; The cross-sectional area ratio of the hydrophilic and oleophobic fiber modules of the internal circulation extraction section (32) and the fiber coagulation acid-water separation module (4) is 0.7-0.

8.

5. The device for deep dechlorination and demetallization of waste bio-oil according to claim 1, characterized in that: The cross-sectional area of ​​the internal circulation extraction section (32) in the acid drop internal circulation deep extraction module (3) is 0.7-0.8 times the cross-sectional area of ​​the horizontal tank body (1); The ratio of the overall length of the fiber coagulation acid-water separation module (4) to the overall length of the acid droplet internal circulation deep extraction module (3) is 1:1-2:

3.

6. A method for deep dechlorination and demetallization of waste bio-oil, characterized in that: The device for deep dechlorination and demetallization of waste bio-oil according to any one of claims 1 to 5 comprises the following steps: (I) Preliminary elution: fine acid droplets are generated by a micro-acid droplet generator (21) and are uniformly emulsified into waste bio-oil to obtain acid-containing waste bio-oil, which is then uniformly injected into a washing core tube (23) through a liquid distributor (22) to enhance mixing of the acid droplets and the oil phase, thereby achieving preliminary elution of chlorine and heavy metals; (II) Deep elution: After the initial elution, the acid-containing waste bio-oil enters the acid droplet inner circulation deep extraction module (3), and after the initial acceleration, enters the inner circulation extraction section (32). The acid droplets adhere to the hydrophilic and oleophobic fiber module. Under the action of the strong shear force of the external fluid, a horseshoe-shaped symmetrical cross-flow zone is formed on both sides of the acid droplets, and an inner circulation occurs to capture the chlorine and heavy metals in the oil phase. At the same time, the inner circulation accelerates the renewal of the acid droplet surface, thereby strengthening the convective mass transfer extraction of chlorine and heavy metals on the basis of diffusion mass transfer, and finally achieving deep elution of chlorine and heavy metals. (III) Acid-water separation: After deep elution, the acid-containing waste bio-oil enters the fiber coagulation acid-water separation module (4), where the fine acid droplets are captured, aggregated, and grown into large acid droplets on the hydrophilic and oleophobic fiber modules, and finally separated from the water bag (13) at the bottom of the horizontal tank (1), and the purified bio-oil is sent to the downstream from the oil discharge port (12).

7. The method for deep dechlorination and demetallization of waste bio-oil according to claim 6, characterized in that: In step (I), the ratio of acid injection in the waste bio-oil is determined according to the metal content in the imported waste bio-oil, as follows: (a) If the total metal content of the imported waste bio-oil is within 100 ppm, the acid injection volume shall be within 5% of the total volume of the oil phase; (b) If the total metal content of the imported waste bio-oil is between 100-500 ppm, the acid injection amount is 6-8% of the total volume of the oil phase; (c) If the total metal content of the imported waste bio-oil is between 500-1000 ppm, the acid injection amount is 8-10% of the total volume of the oil phase.

8. The method for deep dechlorination and demetallization of waste bio-oil according to claim 6, characterized in that: The fine acid droplets are organic acids, and the concentration of the organic acid is 0.5-1wt%; The size of the fine acid droplets generated by the fine acid droplet generator (21) is 50-200 μm.

9. The method for deep dechlorination and demetallization of waste bio-oil according to claim 6, characterized in that: The temperature of the waste bio-oil entering the horizontal tank (1) needs to be controlled at 90-110° C.; the cross-sectional flow rate of the waste bio-oil entering the acid droplet inner circulation deep extraction module (3) is controlled at 0.01-0.015 m / s; and the cross-sectional flow rate of the waste bio-oil entering the fiber coagulation acid-water separation module (4) is controlled at 0.003-0.005 m / s.

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