A three-phase separation device for biomass oil pretreatment

Abstract

The utility model provides a kind of three-phase separation device for biomass oil pretreatment, to solve the problem that biomass raw oil is prone to frequent plugging of disc centrifuge separation equipment in pretreatment process in prior art.The device includes: pickling water washing tank, feed inlet is connected with biomass oil feeding pipe and demetalizing agent feeding pipe;Pretreatment unit, including mixer and reagent adding pipeline;Multi-stage cyclone separation unit, connected with the discharge port of mixer, including at least two groups of cyclone separators connected in series;Heat exchange unit, for heat exchange of mixer and multi-stage cyclone separation unit;Disc centrifuge, feed inlet is connected with the overflow port of the end of multi-stage cyclone separation unit.By setting pretreatment unit and multi-stage cyclone separation unit, flocculation treatment is carried out on biomass oil after pickling water washing, to reduce the content of colloid entering disc centrifuge, thereby reducing the load of centrifuge and the number of shutdown maintenance, effectively improve the continuous operation time length and operation efficiency of device.

Description

Technical Field

[0001] This utility model relates to the technical field of biomass oil processing devices, specifically to a three-phase separation device for biomass oil pretreatment. Background Technology

[0002] In the pretreatment and impurity removal process of biomass feedstock oil, acid washing, water washing, dehydration, and impurity removal are carried out. During the operation, the feedstock acid washing unit produces three types of substances: refined feedstock oil, gum (with adsorbed metal impurities), and wastewater. These three types of substances enter the centrifuge equipment for impurity removal and dehydration. Because the gum and metal impurities in the feedstock are easily adhered to the slag chamber of the disc centrifuge after high-speed centrifugation, the slag chamber and discs are frequently blocked. The equipment blockage requires complete disassembly and cleaning, resulting in high maintenance costs. Utility Model Content

[0003] The purpose of this invention is to provide a three-phase separation device for the pretreatment of biomass oil, so as to solve the problem of frequent clogging of disc centrifuge separation equipment in the pretreatment process of biomass feedstock oil in the prior art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: A three-phase separation device for biomass oil pretreatment, comprising: The pickling water washing tank has a biomass oil feeding pipe and a demetallizing agent feeding pipe connected in parallel at the inlet. The pretreatment unit includes a mixer and a reagent addition pipeline; A multi-stage cyclone separator unit, connected to the discharge port of the mixer, includes at least two sets of cyclone separators connected in series; Heat exchange unit, used for heat exchange in mixer and multi-stage cyclone separator; The disc centrifuge has its feed inlet connected to the overflow port at the end of the multi-stage cyclone separation unit.

[0005] Furthermore, the mixer is a low-shear static mixer.

[0006] Furthermore, the agent addition pipeline includes a flocculant addition pipeline and a demulsifier addition pipeline.

[0007] Furthermore, the separation particle size of the two adjacent sets of cyclone separators decreases step by step.

[0008] Furthermore, the heat exchange unit consists of a first heat exchange component and a second heat exchange component respectively disposed on the surfaces of the mixer and the cyclone separator, with a heat exchange temperature of 75-85°C.

[0009] Furthermore, it also includes a slag storage tank, and the underflow port of the hydrocyclone separator and the slag discharge port of the disc centrifuge are both connected to the slag storage tank.

[0010] The technical solution provided by this utility model has the following advantages compared with the prior art: 1. By setting up a pretreatment unit, heat exchange and chemical flocculation are carried out on the biomass oil after acid washing and water washing, so that the tiny water droplets and colloidal particles in the biomass oil aggregate into high-density flocs, which can be separated and removed by a multi-stage cyclone separation unit. 2. The multi-stage hydrocyclone separation unit uses at least two sets of hydrocyclones, and the particle size of the hydrocyclones decreases step by step, thereby removing impurities such as flocs and metal particles in the biomass oil in stages, improving separation efficiency. Moreover, the hydrocyclones with no powered components undertake most of the separation task, reducing the load on the high-energy-consuming disc centrifuge. 3. During the dosing, mixing and cyclone separation stages, the material temperature is locked at 75-85℃ through a heat exchanger. At this temperature, the kinematic viscosity of biomass oil is significantly reduced. According to Stokes' law, the particle settling velocity is inversely proportional to the viscosity. Therefore, high temperature greatly accelerates the separation process of oil, water and sludge. 4. This device, through the series-connected staged design of the pretreatment unit and the hydrocyclone separator, can remove most of the gum and metal particles in the pickled biomass oil in advance, which greatly reduces the solid load of the subsequent disc centrifuge, so that it only needs to process a small amount of ultrafine particles, thereby avoiding slag chamber blockage and increasing the continuous operation time of the overall system. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; in: 1-Acid washing tank, 2-Mixer, 3-First hydrocyclone, 4-Second hydrocyclone, 5-Disc centrifuge, 6-First heat exchanger, 7-Second heat exchanger, 8-Biomass oil feed pipe, 9-Demetallizer feed pipe, 10-Flocculant feed pipe, 11-Demulsifier feed pipe, 12-Transfer pump, 13-Slag storage tank, 14-Oil outlet pipe, 15-Wastewater tank, 16-Slag discharge pipe, 17-Switch valve. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0014] like Figure 1 As shown, this utility model provides a three-phase separation device for pretreatment of biomass oil, including an acid washing tank 1, a pretreatment unit, a cyclone separation unit, and a disc centrifuge 5 connected in sequence.

[0015] Specifically, the feed inlet of the pickling and washing tank 1 is connected in parallel to the biomass oil feeding pipe 8 and the demetallizing agent feeding pipe 9. The biomass raw oil is deimpurified through pretreatment pickling and washing.

[0016] The pretreatment unit consists of a mixer 2 and a reagent addition pipeline. The mixer 2 is a low-shear static mixer, consisting of a mixing pipeline and spiral guide vanes installed inside the mixing pipeline. The spiral guide vanes have an angle of 15-25° and are made of 316L stainless steel lined with polytetrafluoroethylene (PTFE) or ceramic coating to prevent adhesive adhesion and acid corrosion. The inlet of the mixer 2 is connected to the outlet of the pickling water washing tank 1. The reagent addition pipeline includes a flocculant feeding pipe 10 and a demulsifier feeding pipe 11, which are connected in parallel to one end of the inlet of the mixer 2. Flocculant and demulsifier are added to the mixer 2 through the flocculant feeding pipe 10 and the demulsifier feeding pipe 11, respectively. It should be noted that the demulsifier is added first and then the flocculant. The demulsifier first reduces the interfacial tension between oil and water, causing the emulsified water droplets to coalesce. Subsequently, the flocculant, through adsorption bridging, captures the tiny water droplets and colloidal particles into large flocs.

[0017] The flocculant and demulsifier are uniformly dispersed into the oil-water mixture through mixer 2. Mixer 2 adopts a low shear force (less than the yield strength of colloidal flocs) structure to prevent the formed micro agglomerates from being broken up again during the transportation process, thus creating conditions for subsequent separation.

[0018] The cyclone separation unit includes a first cyclone separator 3 and a second cyclone separator 4. The inlet of the first cyclone separator 3 is connected to the outlet of the mixer 2 via a transfer pump 12, and the overflow port of the first cyclone separator 3 is connected to the inlet of the second cyclone separator 4. In this embodiment, the grading particle size of the first cyclone separator 3 is larger than that of the second cyclone separator 4. After the liquid discharged from the mixer 2 is separated by the first cyclone separator 3, large flocs and wastewater are discharged through the underflow port, while the oil phase enters the second cyclone separator 4 through the overflow port. Small and medium-sized flocs are discharged through the underflow port of the second cyclone separator 4, and the oil phase enters the inlet of the disc centrifuge 5. The first cyclone separator 3 is used to remove large flocs that have already been flocculated. Small and medium-sized colloids that are still suspended after the first-stage cyclone are removed by the second cyclone separator 4. By gradually reducing the separation particle size, the colloid load entering the centrifuge is reduced, thereby reducing adhesion and clogging.

[0019] The hydrocyclone separation unit connects hydrocyclones with different cutting particle sizes in series, allowing the colloids and adsorbed metal impurities to be separated step by step according to the particle size from large to small. This avoids the problems of colloid breakage and re-adhesion caused by single-stage hydrocyclones handling materials with a wide particle size distribution under high shear conditions.

[0020] The heat exchange unit includes a first heat exchanger 6 and a second heat exchanger 7, both of which are jacketed heat exchangers. The first heat exchanger 6 is located on the outer wall of the mixer 2, and the second heat exchanger 7 is located on the outer wall of the first cyclone separator 3 and the second cyclone separator 4. The heat exchange temperature is 75-85℃.

[0021] Biomass oil is a high-viscosity fluid, containing some high-melting-point saturated fatty acid glycerides and waxes. At room temperature, its viscosity is extremely high and it may exhibit non-Newtonian fluid characteristics. Heating it through a heat exchanger can reduce its kinematic viscosity, thereby increasing the settling velocity of particles during centrifugal separation. Moreover, the high-temperature environment helps to weaken the mechanical strength of the oil-water interface. The gums in the biomass oil after acid washing and water washing will form a rigid film at the oil-water interface, hindering water droplet coalescence. High temperature can increase the thermal motion of molecules, disrupt the orderly arrangement of these rigid films, and reduce the interfacial viscosity, allowing demulsifier molecules to diffuse to the interface more quickly and replace natural surfactants, thereby accelerating the demulsification and flocculation process.

[0022] The disc centrifuge 5 is a three-phase disc centrifuge. The feed inlet is connected to the overflow port of the second cyclone separator 4. It is equipped with a light phase outlet, i.e., an oil outlet pipe 14, a heavy phase outlet, i.e., a sewage outlet pipe 15, and a slag discharge pipe 16.

[0023] The device also includes a slag storage tank 13. The underflow ports of the first hydrocyclone 3 and the second hydrocyclone 4, and the slag discharge pipe 16 of the disc centrifuge 5 are all connected to the slag storage tank 13. The impurities discharged from the three enter the interior of the slag storage tank 13.

[0024] In addition, in this embodiment, a switch valve 17 is provided on the biomass oil feeding pipe 8, the demetallizing agent feeding pipe 9, the feed inlet of the pickling water washing tank 1, the flocculant feeding pipe 10, the demulsifier feeding pipe 11, the discharge port of the mixer 2, the overflow port of the first hydrocyclone separator 3 and the second hydrocyclone separator 4, the oil outlet pipe 14 and the sewage pipe 15 of the disc centrifuge 5, and the slag discharge pipe 16, to control the opening and closing of each pipe.

[0025] The following is a specific implementation process based on this solution: Step 1: Acidification reaction; The pre-filtered UCO raw material (containing 50ppm phosphorus, 80ppm total metals, and 2% moisture) is pumped into the acid washing tank 1 through the biomass oil feed pipe 8. At the same time, a phosphoric acid solution with a mass fraction of 85% is added through the metal removal agent feed pipe 9, with an addition amount of 0.15% of the oil weight. The stirring inside the tank is turned on (speed 120rpm). During this process, the phosphoric acid reacts with the non-hydrated phospholipids to generate hydrated phospholipids, and chelates metal ions such as iron, calcium, and magnesium.

[0026] Step 2: Low-shear dosing and flocculation; the reacted material is sent to the pretreatment unit via pump 12 (a single screw pump is selected to reduce shear); Demulsifier injection: At one end of the mixer 2 inlet, a polyether demulsifier (such as polyoxyethylene polyoxypropylene block copolymer) is injected through the demulsifier feed pipe 11 at a dosage of 150 ppm. The demulsifier quickly penetrates to the oil-water interface, replaces the natural surfactant, and reduces the strength of the emulsion film. Flocculant injection: Immediately following, cationic polyacrylamide (CPAM) solution (concentration 0.1%) is injected through flocculant feed pipe 10, with an effective dose of 10 ppm; Static mixing: The material flows through the static mixer 2 with 20° spiral blades. Under the action of a gentle radial flow field, the long-chain molecules of CPAM expand and capture the unstable tiny colloidal particles and water droplets, and rapidly grow into dense flocs with a diameter >100μm through adsorption bridging.

[0027] Step 3: Temperature control and multi-stage cyclone separation; Temperature regulation: Saturated steam at 0.4 MPa is introduced into the first heat exchange component 6 and the second heat exchange component 7 to strictly control the fluid temperature in the mixer and hydrocyclone at 80℃±2℃. At this temperature, the viscosity of UCO is reduced to about 15 cSt, which significantly improves the centrifugal sedimentation rate. Primary separation: The material enters the first hydrocyclone separator 3, and the feed pressure is controlled at 0.25MPa. In the large-diameter hydrocyclone chamber, large flocs and wastewater are thrown to the outer wall under the action of centrifugal force and discharged with the underflow into the slag storage tank 13. About 65% of the volume of impurities are removed in this stage. Two-stage separation: The overflow liquid from the first stage directly enters the second hydrocyclone separator 4, and the feed pressure is maintained at 0.35MPa (using the residual pressure of the pump or intermediate pressurization). In a stronger centrifugal field (small diameter), medium-sized particles of 10-50μm are separated. After two stages of hydrocyclone separation, the total impurity removal rate reaches more than 90%.

[0028] Step 4: Precision centrifugal purification; The overflow liquid from the second-stage hydrocyclone separator 4 enters the disc centrifuge 5. Since most of the colloid has been removed in the previous stage, the gap between the centrifuge discs remains unobstructed, mainly removing residual micron-sized water mist and ultrafine particles. Output: Refined oil is continuously discharged from oil outlet pipe 14. Test results show that the phosphorus content is <3ppm, the total metal content is <5ppm, and the water content is <500ppm, which meets the high standard requirements for biodiesel feedstock. Slag discharge: The slag discharge cycle of the disc centrifuge 5 is set to once every 4 hours (the traditional process requires once every 30 minutes). A very small amount of slag is discharged into the slag storage tank 13 through the slag discharge pipe 16, while the residual wastewater is discharged to the external wastewater pool through the sewage pipe 15.

[0029] Through the processing of the device of this invention, the impurity load of biomass oil is effectively reduced before entering the expensive disc centrifuge 5. In a test of continuous operation for 72 hours, the disc centrifuge 5 did not experience a single vibration alarm or slag discharge failure due to gum accumulation. Moreover, compared with using a centrifuge alone, the overall oil recovery rate of the system increased by 1.5%, because the oil content of the underflow of the hydrocyclone can be optimized by adjusting the diameter of the underflow port of the hydrocyclone, reducing the amount of oil carried away with the slag. In addition, since the number of slag discharges by the disc centrifuge 5 is greatly reduced (the slag discharge process requires a lot of kinetic energy and sealing water), the overall energy consumption is reduced by about 20%.

[0030] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of this utility model.

Claims

1. A three-phase separation device for pretreatment of biomass oil, characterized in that, include: The pickling water washing tank has a biomass oil feeding pipe and a demetallizing agent feeding pipe connected in parallel at the inlet. The pretreatment unit includes a mixer and a reagent addition pipeline; A multi-stage cyclone separator unit, connected to the discharge port of the mixer, includes at least two sets of cyclone separators connected in series; Heat exchange unit, used for heat exchange in mixer and multi-stage cyclone separator; The disc centrifuge has its feed inlet connected to the overflow port at the end of the multi-stage cyclone separation unit.

2. The three-phase separation device for biomass oil pretreatment according to claim 1, characterized in that, The mixer is a low-shear static mixer.

3. The three-phase separation device for biomass oil pretreatment according to claim 1, characterized in that, The reagent addition pipeline includes a flocculant addition pipeline and a demulsifier addition pipeline.

4. The three-phase separation device for biomass oil pretreatment according to claim 1, characterized in that, The separation particle size of the two adjacent sets of cyclone separators decreases step by step.

5. The three-phase separation device for biomass oil pretreatment according to claim 1, characterized in that, The heat exchange unit consists of a first heat exchange component and a second heat exchange component respectively disposed on the surfaces of the mixer and the cyclone separator, with a heat exchange temperature of 75-85°C.

6. The three-phase separation device for biomass oil pretreatment according to claim 1, characterized in that, It also includes a slag storage tank, and the underflow port of the hydrocyclone separator and the slag discharge port of the disc centrifuge are both connected to the slag storage tank.

Images