Lubricant cleaning system and lubricant cleaning method

Abstract

To provide a lubricating oil cleaning system that can more reliably separate lubricating oil and ammonia water from a stock solution containing ammonia water and lubricating oil. [Solution] The lubricating oil cleaning system 100 can purify raw DO contaminated with ammonia into lubricating oil LO. The lubricating oil cleaning system 100 comprises an engine 200, a lubricating oil cleaner 1 that separates raw DO containing lubricating oil LO used in the engine 200 into a light liquid which is purified lubricating oil LO and a heavy liquid which contains ammonia, a separator inlet line 130 for supplying raw DO to the lubricating oil cleaner 1, and an additive means 135 for adding water W to the raw DO in the separator inlet line 130.

Description

Technical Field

[0001] The present invention relates to a lubricating oil cleaning system and a lubricating oil cleaning method for cleaning lubricating oil containing ammonia.

Background Art

[0002] As a measure to promote global warming countermeasures, ammonia fuel that does not emit carbon dioxide, a greenhouse gas, during combustion, has attracted attention as a promising energy for realizing a carbon-neutral society. In recent years, the practical application of ammonia gas turbine engines and ammonia-compatible engine engines that can operate using liquid ammonia as fuel for ships has been progressing. In addition, as for those using liquid ammonia as fuel, development for the operation of ammonia fuel ships as so-called zero-emission ships has also been progressing (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When liquid ammonia is used in an engine such as a ship, there are problems that unburned ammonia gas mixes into the lubricating oil or dissolves in the water in the lubricating oil. Regarding the dissolution in the water in the lubricating oil in detail, moisture mixes into the lubricating oil due to condensation during engine operation or after stopping. When the engine is operated without removing the mixed moisture, the ammonia concentration in the engine increases and ammonia dissolves in the moisture in the lubricating oil. Since ammonia is corrosive, there is a problem that materials exposed to ammonia water or an ammonia atmosphere corrode.

[0005] Furthermore, in a lubricating oil purifier that separates a stock solution containing used lubricating oil into a heavy liquid and a light liquid (lubricating oil), if ammonia is mixed into the stock solution, the specific gravity of the heavy liquid will decrease, resulting in a decrease in the removal rate of the heavy liquid. This may cause problems such as the light liquid (lubricating oil) leaking out from the heavy liquid side or the heavy liquid mixing with the light liquid. Therefore, there is a strong desire for the emergence of a technology that can effectively separate lubricating oil from a raw lubricating oil containing ammonia, thereby obtaining clean lubricating oil.

[0006] The present invention aims to solve the aforementioned problems and provide a lubricating oil cleaning system and lubricating oil cleaning method that can remove ammonia from a stock solution containing ammonia and lubricating oil to obtain clean lubricating oil. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention provides a lubricating oil cleaning system capable of cleaning lubricating oil contaminated with ammonia or ammonia water, comprising: an engine; a lubricating oil cleaner that separates a stock solution containing the lubricating oil used in the engine into a light liquid which is the cleaned lubricating oil and a heavy liquid which contains ammonia; a route for supplying the stock solution to the lubricating oil cleaner; and an additive means for adding water to the stock solution in the route.

[0008] Furthermore, the present invention relates to a method for purifying lubricating oil that has been contaminated with ammonia or ammonia water, comprising: a water addition step of adding water to a stock solution containing the lubricating oil used in an engine, in a path for supplying the stock solution to a lubricating oil purifier; and a centrifugal separation step of separating the stock solution containing the lubricating oil into a light liquid which is the lubricating oil that has been purified by the lubricating oil purifier and a heavy liquid which contains ammonia. [Effects of the Invention]

[0009] The lubricating oil cleaning system and lubricating oil cleaning method of the present invention can separate lubricating oil and ammonia from a stock solution containing ammonia and lubricating oil. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing a lubricating oil cleaning system and lubricating oil cleaning method according to an embodiment of the present invention. [Figure 2] This is a central longitudinal cross-sectional view showing a lubricating oil cleaner. [Figure 3] This is a vertical cross-sectional view of the central rotating body of a lubricating oil cleaner. [Figure 4] This is a block diagram showing a first modified example of a lubricating oil cleaning system and lubricating oil cleaning method according to an embodiment of the present invention. [Figure 5] This is a block diagram showing a second modified example of a lubricating oil cleaning system and lubricating oil cleaning method according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] A lubricating oil cleaning system 100 and a lubricating oil cleaning method according to an embodiment of the present invention will be described in detail with reference to Figures 1 to 4.

[0012] ≪Lubricant Cleaning System≫ The lubricating oil cleaning system 100 shown in Figure 1 is a purifier for cleaning and reusing used fluids (undiluted DO) such as lubricating oil LO (see Figure 3), fuel oil, and bilge water used in engines 200 installed on ships, in limited onshore installation spaces (for example, island power plants or existing power plants). The following explanation will describe an example of the lubricating oil cleaning system 100 according to the present invention, using the case where the lubricating oil LO used in an engine 200 that burns liquid ammonia as fuel is used as the used fluid (undiluted DO). In engine 200, which uses liquid ammonia as fuel, there is a possibility that sludge SG, ammonia, ammonia water AW, etc. may be mixed into the lubricating oil LO inside engine 200.

[0013] The lubricating oil cleaning system 100 includes a lubricating oil cleaner 1 as shown in Figures 1 and 3. The lubricating oil cleaner 1 separates the raw liquid DO, which contains lubricating oil LO mixed with ammonia and aqueous ammonia AW, into a light liquid which is the cleaned lubricating oil LO, a heavy liquid which is aqueous ammonia AW which contains ammonia, and sludge SG (solids). The lubricating oil cleaner 1 consists of, for example, a three-phase separation type separation plate centrifuge. More specifically, the lubricating oil cleaning system 100 mainly comprises a lubricating oil tank 300, a lubricating oil supply pump P1, a heater 400, a lubricating oil purifier 1, a sludge tank 700, a water supply line 110 (water supply means), a heavy liquid discharge line 120 (drainage means), a separator inlet line 130, an additive means 135, a mixing means 137, a sludge discharge line 160, a working water discharge line 190, and a control device 900, as shown in Figure 1 or Figure 3. The lubricating oil cleaning system 100 is located inside a ship.

[0014] In the lubrication oil cleaning system 100, a path is formed by the lubrication oil discharge line 150, the lubrication oil tank 300, and the separator inlet line 130 to supply the raw DO discharged from the engine 200 to the lubrication oil cleaner 1. Here, "pathway" refers to any path that supplies the raw DO discharged from the engine 200 to the lubricating oil purifier 1. Examples of such paths include the separator inlet line 130, the raw DO return line 133, the light liquid discharge line 140, the lubricating oil discharge line 150, and the lubricating oil tank 300. Furthermore, a pressure sensor 810, a moisture detection sensor 820, and an ammonia sensor 830 may be placed in the light liquid discharge line 140.

[0015] ≪Organization≫ The engine 200 shown in FIG. 1 is a marine diesel engine arranged inside a ship, which uses liquid ammonia with zero emission of carbon dioxide, a greenhouse gas, as fuel, and may be a turbine engine. The engine 200 consists of a mechanism that connects the crankshaft and the piston only with a connecting rod. In the engine 200, side pressure, which is a lateral force, is generated on the piston, causing uneven wear on the cylinder. Therefore, lubricating oil LO is used in the engine 200 to improve the movement of the piston. The engine 200 may also be one that co - burns liquid ammonia and fossil fuels such as natural gas.

[0016] ≪Lubricating Oil Drain Line≫ The lubricating oil drain line 150 shown in FIG. 1 is a pipeline for sending the lubricating oil LO (stock solution DO) used in the engine 200 to the lubricating oil tank 300. One end of the lubricating oil drain line 150 is connected to the engine 200, and the other end is connected to the lubricating oil tank 300.

[0017] ≪Lubricating Oil Tank and Lubricating Oil≫ As shown in FIG. 1, the lubricating oil tank 300 is a tank for storing the stock solution DO containing the lubricating oil LO used in the engine 200. The stock solution DO supplied from the engine 200 to the lubricating oil tank 300 contains ammonia derived from ammonia fuel. Therefore, the lubricating oil tank 300 consists of a tank with a lid (a sealed tank) that prevents the ammonia vaporized from the stock solution DO from leaking outside the lubricating oil tank 300. Also, the stock solution DO contains aqueous ammonia AW mixed in the engine 200. The specific gravity of the stock solution DO is 0.90 - 0.96.

[0018] ≪Aqueous Ammonia and Water≫ Ammonia water AW is an alkaline aqueous solution in which ammonia (NH3) is dissolved in water W supplied from a water storage tank 139 (described later) and moisture mixed into the lubricating oil due to condensation during or after engine operation. Ammonia water AW has a characteristic pungent odor. Ammonia water AW may corrode fluororubber O-rings used in the lubricating oil purifier 1, as well as heavy and light liquid impellers made of copper alloy. For this reason, it is preferable that these parts be made of corrosion-resistant materials.

[0019] Furthermore, the specific gravity of aqueous ammonia (AW) is lighter than that of water (W), which is 1.0. For example, the specific gravity of aqueous ammonia (AW) is 0.9 at an ammonia concentration of approximately 28%, and 0.88 at a concentration of approximately 35%. Since the specific gravity of aqueous ammonia (AW) changes depending on the ammonia concentration, the position of the separation interface SB in the separation chamber SZ of the lubricating oil purifier 1 moves radially, as shown in Figure 3.

[0020] ≪Separator Inlet Line≫ The separator inlet line 130 shown in Figure 1 is a piping system for supplying the raw DO (sludge SG, ammonia water AW, and lubricating oil LO mixed with ammonia) stored in the lubricating oil tank 300 to the lubricating oil purifier 1. The separator inlet line 130 consists of a heater upstream line 131 from the lubricating oil tank 300 to the heater 400, and a heater downstream line 132 from the heater 400 to the lubricating oil purifier 1. The heater upstream line 131 is equipped with a lubricating oil supply pump P1. The heater downstream line 132 is equipped with an additive means 135, a mixing means 137, and a three-way valve 134.

[0021] Lubrication oil supply pump The lubricating oil supply pump P1 is a pump for sending the raw DO in the lubricating oil tank 300 to the lubricating oil purifier 1 via the separator inlet line 130. The lubricating oil supply pump P1 is installed in the heater upstream line 131. In this embodiment, the lubricating oil supply pump P1 is installed between the lubricating oil tank 300 and the heater 400. The raw DO in the lubricating oil tank 300 is supplied to the lubricating oil purifier 1 via the heater 400, mixing means 137, and three-way valve 134. The raw DO in the heater upstream line 131 contains ammonia water AW and ammonia, and some of the ammonia in the raw DO in the heater downstream line 132 may gasify.

[0022] Heater The heater 400 is an oil heater that heats the lubricating oil LO (undiluted DO) sent to the lubricating oil purifier 1. The heater 400 is installed between the lubricating oil supply pump P1 and the additive means 135 in the separator inlet line 130. The heater 400 heats the lubricating oil LO to about 90°C, for example. By heating the lubricating oil LO and lowering its viscosity, the heater 400 can improve the separation efficiency of solids, water, or both in the lubricating oil purifier 1.

[0023] <<Return line for undiluted solution and three-way valve>> The undiluted fluid return line 133 is a piping route for returning the undiluted DO in the separator inlet line 130 to the lubricating oil tank 300. The undiluted fluid return line 133 can return the flow of undiluted DO to the lubricating oil tank 300 by switching the three-way valve 134 when necessary for operation of the lubricating oil purifier 1, such as when sludge is discharged, when an alarm is triggered, or when displacement water / seal water is added.

[0024] <Water storage tanks and water supply lines> The water storage tank 139 is a tank for storing water W to be supplied to the additive means 135. The water storage tank 139 is connected to the additive means 135 via the water supply line 136. Alternatively, the additive means 135 may be connected to the water supply line 110 instead of the water storage tank 139 and the water supply line 136, so that water W is supplied from the water supply line 110.

[0025] ≪Addition means≫ The additive means 135 is a device for adding water W to the raw DO in the separator inlet line 130. The additive means 135 consists of, for example, a nozzle connected to the separator inlet line 130. The additive means 135 is installed downstream of the heater 400 in the separator inlet line 130. The raw DO in the heater downstream line 132, downstream of the additive means 135, is mixed with ammonia water AW, gaseous ammonia, water W added from the additive means 135, etc. In the separator inlet line 130, a mixing means 137 for mixing water W and the raw DO is provided downstream of the additive means 135, or on the additive means 135. The adding means 135 and the mixing means 137 may be installed, for example, between the heater 400 and the three-way valve 134 of the separator inlet line 130, as shown in Figure 1, or between the three-way valve 134 and the lubricating oil purifier 1 of the separator inlet line 130, as shown in Figure 5. Furthermore, the adding means 135 and the mixing means 137 may be installed both upstream and downstream of the heater 400 in the separator inlet line 130.

[0026] ≪Mixing means≫ The mixing means 137 is a mixer for mixing the raw DO in the separator inlet line 130 with the water W added by the additive means 135. The mixing means 137 consists of a static mixer installed in the separator inlet line 130. The static mixer promotes the generation of ammonia water AW by disturbing the flow of liquid in the piping, thereby bringing the gasified ammonia contained in the raw DO into contact with the water W added by the additive means 135. It consists of piping that incorporates stirring elements and impellers for dividing, reversing, and rotating the fluid.

[0027] <<Light liquid discharge line>> The light liquid discharge line 140 is a flow path for returning the lubricating oil LO (light liquid) that has been purified by the lubricating oil purifier 1 back to the lubricating oil tank 300. The light liquid discharge line 140 consists of a piping route from the discharge port of the lubricating oil purifier 1 to the lubricating oil supply port of the lubricating oil tank 300.

[0028] Lubricant Cleaner The lubricating oil purifier 1 is a device for separating / removing sludge SG (solids) and ammonia water AW contained in the raw DO supplied from the lubricating oil tank 300 from the lubricating oil LO. The lubricating oil purifier 1 may also be a separator plate type centrifuge that separates the raw DO into three phases of liquid (light liquid) - liquid (heavy liquid) - solids by the centrifugal force of a rotating body 3 (see Figure 2) that rotates at high speed. Onboard the ship, the lubricating oil purifier 1 is connected to a separator inlet line 130 and a light liquid discharge line 140.

[0029] Next, the lubricating oil purifier 1, which consists of a separator plate type centrifugal separator, will be described in more detail with reference to Figures 2 and 3. As shown in Figure 3, the lubricating oil cleaner 1 is a centrifugal separator (centrifugal sedimentation machine) in which numerous separation plates 13 made of truncated cone-shaped thin plates are stacked at intervals in the axial direction of the guide cylinder 5 inside a rotating body 3. The lubricating oil cleaner 1 has a mechanism for discharging sludge SG accumulated on the inner wall of the rotating body 3 to the outside by opening and closing a valve cylinder 6. The lubricating oil cleaner 1 comprises a rotating shaft 2, a rotating body 3, a guide cylinder 5, a separation chamber SZ, a valve cylinder 6, a light liquid discharge section 9 (see Figure 2), and a heavy liquid discharge section 15.

[0030] <Rotation axis> As shown in Figure 2, the rotating shaft 2 has a gear portion 2a that meshes with a speed-increasing gear 21 which is rotationally driven by an electric motor (not shown), and is rotated by the electric motor (not shown) via the speed-increasing gear 21.

[0031] <Rotating body> As shown in Figure 3, the rotating body 3 is a component attached to the rotation shaft 2 and rotates at high speed around the rotation shaft 2. The rotating body 3 has a shape in which the upper half is a roughly truncated cone-shaped section and the lower half is a large-diameter cylindrical section with a diameter larger than the large diameter of the truncated cone-shaped section, formed integrally. The rotating body 3 is fixed to the rotation shaft 2.

[0032] <Liquid inlet pipe> As shown in Figure 3, the liquid inlet pipe 4 is a pipe for supplying the undiluted liquid DO (lubricating oil LO used in engine 200) and water W into the rotating body 3. The liquid inlet pipe 4 is located at the top of the center of the rotating body 3. The water supply line 110 and the separator inlet line 130 (see Figure 2) are connected to the upstream side of the liquid inlet pipe 4. In addition, the water W supplied to the separation chamber SZ of the lubricating oil purifier 1 is introduced into the rotating body 3 from the water supply line 110 via the liquid inlet pipe 4.

[0033] <Information tube> The guide tube 5 is a component that guides the raw liquid DO and water W, which have been introduced into the rotating body 3 from the liquid inlet pipe 4, from the bottom of the rotating body 3 to the separation chamber SZ. The guide tube 5 consists of a flared cylindrical body and is located in the center of the rotating body 3.

[0034] <Separation room> As shown in Figure 3, the separation chamber SZ is a chamber for separating the raw DO into its components based on differences in specific gravity using centrifugal force. The separation chamber SZ consists of a circular space when viewed in cross-section. Multiple stacked separation plates 13 are arranged in the separation chamber SZ. The separation chamber SZ comprises a separation region where the stacked separation plates 13 are arranged, and a sludge accumulation region at the outermost diameter of the rotating body 3. As the raw DO introduced into the separation chamber SZ flows upward through the gaps between the separation plates 13, the sludge SG with the highest specific gravity accumulates in the outer sludge accumulation region, the heavier liquid (ammonia water AW or water W) with a lower specific gravity than sludge SG moves to the region between the sludge accumulation region and the separation region, and the lighter liquid (lubricating oil LO) with the lowest specific gravity moves towards the center of the rotating body 3. The lighter liquid (purified lubricating oil LO) is discharged to the outside from the lighter liquid discharge section 9 (see Figure 2) located at the top of the rotating body 3. The ammonia water (heavy liquid) AW separated in the separation chamber SZ is discharged to the outside through the heavy liquid discharge line 120 and leak detector 840 from the heavy liquid discharge section 15 formed between the water intake plate TD and the inner wall of the upper part of the rotating body 3.

[0035] <Valve Cylinder> The valve cylinder 6 is a valve body that opens and closes the sludge discharge port 12 (the part that is in contact with the valve packing 7). When the pilot valve V is opened to drain the water below the valve cylinder 6, the valve cylinder 6 descends, the sludge discharge port 12 opens, and the sludge SG is discharged. Below the valve cylinder 6, there is an operating water supply port 61 that supplies operating water for opening and closing the valve cylinder.

[0036] <Light liquid discharge section> As shown in Figure 2, the light liquid discharge section 9 is a part for discharging the lubricating oil LO (light liquid) separated in the separation chamber SZ to the outside. A light liquid discharge line 140 is attached to the light liquid discharge section 9.

[0037] <Heavy liquid discharge part> As shown in Figure 2, the heavy liquid discharge section 15 is the part that discharges the ammonia water (heavy liquid) separated in the separation chamber SZ to the outside. A heavy liquid discharge line 120 is attached to the heavy liquid discharge section 15.

[0038] <Sludge discharge line> As shown in Figure 3, the sludge discharge line 160 (sludge discharge means) is a discharge path for discharging sludge SG, which has been centrifuged in the lubricating oil purifier 1, to the outside of the lubricating oil purifier 1. The sludge discharge line 160 is connected to the sludge outlet 12 on its upstream side and to the sludge tank 700 on its downstream side (see Figure 1). The sludge SG in the lubricating oil purifier 1 is discharged into the sludge discharge line 160, stored in the sludge tank 700, and then discarded.

[0039] <Working water discharge line> As shown in Figure 2, the working water discharge line 190 (water discharge line) is a discharge passage for discharging the cleaning water injected into the frame 3A of the lubricating oil purifier 1. The working water discharge line 190 is connected to the lubricating oil purifier 1 on its upstream side and to the sludge tank 700 on its downstream side (see Figure 1). Depending on the arrangement, the working water discharge line may be connected to a tank other than the sludge tank 700.

[0040] <Sludge Tank> The sludge tank 700 is a tank for storing waste liquid SW and sludge SG discharged from the lubricating oil purifier 1. A vent 710 is provided at the top of the sludge tank 700 to discharge ammonia gas and other vapors from the waste liquid SW to the outside of the sludge tank 700. If the waste liquid SW in the sludge tank 700 is 40°C or higher, a cooling device may be installed to cool the waste liquid SW.

[0041] <Water supply line> As shown in Figure 3, the water supply line 110 is a water supply means that supplies water W (seal water / displacement water) into the separation chamber SZ (inside the rotating body 3). Furthermore, while the lubricating oil purifier 1 is in operation (while the process of separating aqueous ammonia AW from the raw solution DO is being performed), it is preferable to control the position of the separation interface SB by intermittently or continuously supplying water W into the separation chamber SZ to adjust the specific gravity of aqueous ammonia AW (heavy liquid). In addition, during maintenance of the lubricating oil purifier 1, the water supply line 110 supplies cleaning water into the separation chamber SZ. The water supply line 110 is provided with a valve SV3 (not shown) that adjusts the water supply into the separation chamber SZ (inside the rotating body 3). Alternatively, the water supply line 110 adjusts the water supply by controlling the valve SV3 by the control unit 910 and timer 920 based on the measurement value of one of the following: pressure sensor 810, moisture detection sensor 820, ammonia sensor 830, or leak detector 840.

[0042] <Nozzle water supply line> As shown in Figure 2, the nozzle water supply line 111 is a water supply means for sending water W to the nozzle 112.

[0043] <Nozzle> The nozzle 112 is attached to the nozzle water supply line 111 and sprays water W in a shower-like manner into the frame 3A surrounding the rotating body 3. Water droplets of ammonia water AW discharged into the frame 3A along with the sludge from the sludge discharge port 12 are washed away by the water W sprayed (misted) into the frame 3A, and ammonia that has gasified in the frame 3A dissolves in the water W sprayed (misted) into the frame 3A. The nozzle 112 is inserted into the upper part of the frame 3A (above the sludge discharge port 12).

[0044] <Heavy liquid discharge line> As shown in Figure 3, the heavy liquid discharge line 120 (drainage means) is a flow path through which the ammonia water AW (separated water) centrifuged in the lubricating oil purifier 1 is discharged, and is connected to the heavy liquid discharge section 15 of the lubricating oil purifier 1. The ammonia water AW (heavy liquid) in the lubricating oil purifier 1 overflows from the heavy liquid discharge section 15 and is released into the heavy liquid discharge line 120, where it is stored in the sludge tank 700 and then discarded. A leak detector 840 may be provided in the heavy liquid discharge line 120.

[0045] <Pressure Sensor> The pressure sensor 810 is a measuring instrument that measures the pressure of the light liquid discharged from the light liquid discharge section 9 of the lubricating oil cleaner 1. The pressure sensor 810 is electrically connected to the control unit 910.

[0046] <Moisture detection sensor> The moisture detection sensor 820 is a measuring instrument that measures the amount of moisture in the light liquid discharged from the light liquid discharge section 9 of the lubricating oil cleaner 1. The moisture detection sensor 820 is electrically connected to the control unit 910. The moisture detection sensor 820 may be omitted depending on the condition of the lubricating oil LO.

[0047] <Ammonia Sensor> The ammonia sensor 830 is a measuring instrument that measures the ammonia concentration of the ammonia water AW discharged from the light liquid discharge section 9 of the lubricating oil purifier 1. The ammonia sensor 830 is electrically connected to the control unit 910. The ammonia sensor 830 may be omitted depending on the condition of the lubricating oil LO.

[0048] <Leak detector> The leak detector 840 is a measuring instrument that mechanically measures the heavy liquid discharged from the heavy liquid discharge section 15 of the lubricating oil cleaner 1. The leak detector 840 is electrically connected to the control unit 910. The leak detector 840 may be omitted depending on the condition of the lubricating oil LO.

[0049] <Control device> The control device 900 shown in Figure 3 has the function of supplying water W to the lubricating oil purifier 1 intermittently or continuously at a preset timing or at any timing, thereby maintaining the specific gravity of the ammonia water AW (heavy liquid) in the separation chamber SZ at or above a predetermined value. The control device 900 is composed of a control unit 910 and a timer 920. The control unit 910 is connected to the timer 920, a pressure sensor 810, a moisture detection sensor 820, an ammonia sensor 830, and a leak detector 840.

[0050] <Cleaning lubricant> The clean lubricating oil is lubricating oil LO that has been purified by the lubricating oil purifier 1. The clean lubricating oil is then stored again in the lubricating oil tank 300 via the light liquid discharge line 140 from the lubricating oil purifier 1, and then supplied to the ship's engine or auxiliary equipment (e.g., generator, boiler, etc.).

[0051] ≪Effect≫ Next, the operation of the lubricating oil cleaning system 100 and lubricating oil cleaning method according to an embodiment of the present invention will be described with reference to Figures 1 to 4.

[0052] For example, as shown in Figure 1, the lubricating oil LO (undiluted DO) used in the engine 200 is stored in the lubricating oil tank 300. The undiluted DO stored in the lubricating oil tank 300 is introduced into the lubricating oil purifier 1 from the separator inlet line 130 via the heater 400, the additive means 135, the mixing means 137, and the three-way valve 134.

[0053] In the separator inlet line 130, a water addition process is performed in which water W is added to the raw DO in the separator inlet line 130. As a result, the ammonia contained in the raw DO in the separator inlet line 130 and the ammonia gasified from the raw DO dissolve in the water W supplied by the addition means 135 to form aqueous ammonia AW. Furthermore, by adding water W to the separator inlet line 130, the ammonia concentration in the raw DO can be diluted, thus preventing the concentration of aqueous ammonia AW in the raw DO from becoming too high.

[0054] In the separator inlet line 130, a heating process is performed in which the raw DO in the separator inlet line 130 is heated by the heater 400. Heating the raw DO (lubricating oil LO) reduces its viscosity, thereby improving the separation efficiency of solids and water in the lubricating oil purifier 1. In addition, heating the lubricating oil LO causes the ammonia that was trapped in the lubricating oil LO to gasify, making it easier for it to come into contact with water W.

[0055] Furthermore, at the separator inlet line 130, a mixing process is performed in which the water W added in the water addition process and the raw DO are mixed by a mixing means 137. The mixing means 137 efficiently brings the ammonia in the raw DO and the ammonia gasified from the raw DO into contact with the water W, thereby promoting the generation of ammonia water.

[0056] In the lubricating oil purifier 1, a centrifugal separation process is performed to separate the raw solution DO, which contains ammonia water AW and lubricating oil LO, into a light liquid (lubricating oil LO) and a heavy liquid (ammonia water AW). Because the lubricating oil purifier 1 separates the lubricating oil LO (light liquid) and ammonia water AW (heavy liquid) from the raw solution DO, it is possible to suppress the residue of ammonia in the lubricating oil cleaning system 100.

[0057] Furthermore, the undiluted DO introduced into the lubricating oil purifier 1 flows upward between multiple stacked separation plates 13, as shown in Figure 3. Normally, components with a higher specific gravity (sludge SG, water W, etc.) move to the outermost diameter side of the rotating body 3 and are separated. Components with a lower specific gravity (lubricating oil LO) move towards the center side of the rotating body 3 and are separated.

[0058] Generally, when a stock solution DO mixed with aqueous ammonia AW is supplied into a rotating body 3, the stock solution DO is separated into lubricating oil LO, aqueous ammonia AW, and sludge SG.

[0059] Ammonia water AW has a lower specific gravity than water W which does not contain ammonia, resulting in a smaller difference in specific gravity between the light liquid (lubricating oil LO) and the heavy liquid (ammonia water AW). Therefore, the separation efficiency between the light liquid (lubricating oil LO) and the heavy liquid (ammonia water AW) may decrease. In addition, the separation interface SB between ammonia water AW and lubricating oil LO is pushed outward by the lubricating oil LO. Consequently, if the ammonia concentration in ammonia water AW becomes high (for example, if the ammonia concentration exceeds 6 wt%), there is a risk that the light liquid may leak (flow out into the heavy liquid discharge line 120) when performing three-phase separation (when performing purifier operation). Furthermore, when the concentration of aqueous ammonia AW is high, the difference in specific gravity between the light liquid and the heavy liquid becomes small, preventing the water W that accumulates inside the rotating body 3 from positioning the separation interface SB in an ideal location.

[0060] In this embodiment, during the centrifugal separation step of the raw solution DO mixed with aqueous ammonia AW (centrifugation step), water is supplied into the separation chamber SZ (water injection step), thereby restoring the specific gravity of aqueous ammonia AW in the separation chamber SZ to above a predetermined value. In this way, by introducing water W into the separation chamber SZ, the specific gravity of aqueous ammonia AW can be maintained above a certain value, thereby minimizing the loss of lubricating oil LO (light liquid flowing out to the heavy liquid discharge section 15) and enabling stable normal operation.

[0061] The water injection process may be performed intermittently or continuously using the timer 920 and control device 900 shown in Figure 3. Alternatively, it may be performed when at least one of the following measurements—pressure sensor 810, moisture detection sensor 820, ammonia sensor 830, and leak detector 840—reaches a threshold value. In this way, the specific gravity of the ammonia water AW can be maintained above a predetermined value (i.e., the difference in specific gravity between the ammonia water AW and the lubricating oil LO in the separation chamber SZ can be maintained above a predetermined value).

[0062] The discharge of ammonia water AW and sludge SG in the discharge process may be performed at regular intervals using the timer 920 and control device 900, or when the measured value of at least one of the pressure sensor 810, moisture detection sensor 820, ammonia sensor 830, and leak detector 840 reaches a threshold. Note that the discharge process and the water injection process are not performed simultaneously, but only one of them is performed at a time.

[0063] As described above, according to this embodiment, the ammonia mixed in the raw DO and the ammonia gasified from the raw DO are dissolved in the water W added to the separator inlet line 130 by the addition means 135. Therefore, the ammonia mixed in the raw DO and the ammonia gasified from the raw DO can be converted into ammonia water AW. Furthermore, the raw DO mixed with ammonia water AW is separated into ammonia water AW, lubricating oil LO, and sludge SG by the lubricating oil purifier 1, so that purified lubricating oil LO can be obtained.

[0064] The lubricating oil cleaning system 100 according to this embodiment is a lubricating oil cleaning system 100 that can clean lubricating oil (raw DO) contaminated with ammonia, and comprises an engine 200, a lubricating oil cleaner 1 that separates raw DO containing lubricating oil LO contaminated with ammonia used in the engine 200 into a light liquid which is the cleaned lubricating oil LO and a heavy liquid which contains ammonia, a path (for example, a separator inlet line 130) for supplying raw DO to the lubricating oil cleaner 1, and an adding means 135 for adding water W to the raw DO in the separator inlet line 130.

[0065] The lubricating oil cleaning system 100 with this configuration is equipped with an additive means 135, which allows water W to be added to the raw DO in the path (for example, the separator inlet line 130) to dissolve the ammonia in the raw DO in the water W. Then, by supplying the raw DO containing ammonia water AW and lubricating oil LO to the lubricating oil cleaner 1, the lubricating oil LO and ammonia water AW can be separated. Furthermore, the additive means 135 adds water W to the raw DO in the separator inlet line 130, thereby adjusting the specific gravity difference between the light liquid (lubricating oil LO) and the heavy liquid (ammonia water AW) in the separation chamber SZ to a size suitable for sedimentation separation. As a result, the lubricating oil purifier 1 can more reliably separate the lubricating oil LO from the ammonia water AW in the raw DO containing ammonia water AW and lubricating oil LO, thereby obtaining purified lubricating oil LO.

[0066] Furthermore, as shown in Figure 1, the lubricating oil cleaning system 100 is equipped with a heater 400 in the path (for example, the separator inlet line 130) for heating the raw DO sent to the lubricating oil cleaner 1, and the addition means 135 is installed downstream of the heater 400 in the separator inlet line 130.

[0067] With this configuration, the viscosity of the raw DO (lubricating oil LO) can be reduced by heating, thereby improving the separation efficiency of solids and water in the lubricating oil purifier 1. In addition, by heating the lubricating oil LO with the heater 400, the ammonia released from the lubricating oil LO comes into contact with water W more easily, so that the ammonia in the raw DO can be dissolved in water W.

[0068] Furthermore, as shown in Figure 1, the lubricating oil cleaning system 100 is provided with a mixing means 137 for mixing water W and undiluted DO.

[0069] With this configuration, ammonia in the stock solution DO and water W can be efficiently brought into contact and mixed.

[0070] Furthermore, the mixing means 137 shown in Figure 1 is a static mixer installed in the path (for example, the separator inlet line 130).

[0071] By using a static mixer as the mixing means 137, the ammonia of the lubricating oil LO and the water W can be efficiently mixed. Furthermore, since the static mixer has no moving parts, maintenance costs and installation space can be reduced, and energy can be saved.

[0072] Furthermore, the lubricating oil cleaning method of this embodiment is a lubricating oil cleaning method that can clean lubricating oil (raw DO) contaminated with ammonia, and includes a water addition step of adding water W to the raw DO containing lubricating oil LO used in engine 200 in a path (for example, a separator inlet line 130) for supplying the raw DO to the lubricating oil cleaner 1, and a centrifugal separation step of separating the raw DO containing lubricating oil LO into a light liquid which is lubricating oil LO that has been cleaned by the lubricating oil cleaner 1 and a heavy liquid which contains ammonia.

[0073] This lubricating oil cleaning method includes a water addition step in which water W is added to the raw DO in the pathway (separator inlet line 130), thereby dissolving the ammonia in the separator inlet line 130 into the water W. Furthermore, by adding water W to the raw DO, the specific gravity of the ammonia water AW contained in the raw DO increases, making the specific gravity difference between the light liquid (lubricating oil LO) and the heavy liquid (ammonia water AW) suitable for sedimentation separation. As a result, the raw DO containing ammonia and lubricating oil LO can be separated into lubricating oil LO and ammonia water AW, thereby obtaining cleaned lubricating oil LO.

[0074] Furthermore, as shown in Figure 1, the process includes a mixing step in which the water W added in the water addition step is mixed with the stock solution DO.

[0075] With this configuration, ammonia in the raw DO can be efficiently dissolved in water W to produce aqueous ammonia AW, and by supplying the raw DO containing aqueous ammonia AW and lubricating oil LO to the lubricating oil purifier 1, the lubricating oil LO and aqueous ammonia AW can be separated.

[0076] Furthermore, as shown in Figure 1, the lubricating oil cleaning method includes a heating step of heating the raw DO in the path (for example, the separator inlet line 130).

[0077] This lubricating oil cleaning method allows the viscosity of the raw DO (lubricating oil LO) to be reduced by heating, thereby improving the separation efficiency of solids and water in the lubricating oil cleaner 1. In addition, since ammonia is released from the lubricating oil LO, it comes into contact more easily with the water W added in the water addition step.

[0078] [First variation] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of its technical concept. Naturally, the present invention also extends to these modified and altered inventions. Furthermore, components already described are denoted by the same reference numerals, and their descriptions are omitted. Figure 4 is a block diagram showing a first modified example of a lubricating oil cleaning system and lubricating oil cleaning method according to an embodiment of the present invention.

[0079] The lubricating oil cleaning system 100 of the embodiment shown in Figure 1 is described in which a heater 400 is provided in the separator inlet line 130 to heat the raw DO sent to the lubricating oil cleaner 1, and an additive means 135 is installed downstream of the heater 400 in the path (for example, the separator inlet line 130). The present invention is not limited thereto, and as shown in Figure 4, the additive means 135 may be installed upstream of the heater 400 in the separator inlet line 130.

[0080] In this case, the additive means 135 is supplied with water W from the water storage tank 139 or water W from the water supply line 110 (see Figure 3). A mixing means 137 may also be provided between the additive means 135 and the heater 400 in the heater upstream line 131. Although not shown in the figures, the mixing means 137 may also be provided downstream of the heater 400, or the mixing means 137 may be omitted.

[0081] By installing the additive means 135 upstream of the heater 400 in the separator inlet line 130, ammonia in the raw DO can be easily dissolved in water W. The ammonia water AW and lubricating oil LO in the raw DO can be separated by the lubricating oil purifier 1 to produce lubricating oil LO with fewer impurities.

[0082] [Second variation] Figure 5 is a block diagram showing a second modified example of a lubricating oil cleaning system and lubricating oil cleaning method according to an embodiment of the present invention.

[0083] The three-way valve 134, located upstream of the undiluted liquid return line 133 shown in Figure 1, may also be located between the heater 400 and the additive means 135 in the heater downstream line 132, as shown in Figure 5. In this way, the undiluted liquid DO flowing through the separator inlet line 130 may be returned to the lubricating oil tank 300.

[0084] [Other variations] In the above embodiment, as shown in Figure 1, a case in which only one lubricating oil cleaner 1 is installed was described, but multiple lubricating oil cleaners 1 may be arranged in parallel.

[0085] In the above embodiment, as shown in Figures 1 and 4, a case was described in which a mixing means 137 is installed in the heater upstream line 131 or heater downstream line 132 of the separator inlet line 130. However, the mixing means 137 can be installed in the separator inlet line 130 as needed and may be omitted.

[0086] In the above embodiment, as shown in Figure 2, an example was given in which the water supply line 110 (water supply means) is connected to the liquid inlet pipe 4. However, the water supply line 110 (water supply means) may also be connected to the lubricating oil tank 300 located in the middle of the path for supplying the undiluted DO to the lubricating oil purifier 1, or it may be connected to the lubricating oil discharge line 150.

[0087] In the above embodiment, the example given was that the lubricating oil purifier 1 is a three-phase separation type separation plate centrifuge, but a two-phase separation type separation plate centrifuge may also be used. In this case, the lubricating oil purifier 1 separates the raw liquid DO, which is lubricating oil LO mixed with aqueous ammonia AW, into sludge SG containing a heavy liquid containing aqueous ammonia AW and a light liquid, which is purified lubricating oil LO. When a two-phase separation type separator plate centrifugal separator is used as the lubricating oil purifier 1, it is preferable to discharge the oil when the measured value of any of the following sensors in the lubricating oil purifier 1—the pressure sensor 810, the moisture detection sensor 820, the ammonia sensor 830, and the leak detector 840—reaches a threshold value. The moisture sensor 820, the ammonia sensor 830, and the leak detector 840 may be omitted depending on the condition of the lubricating oil LO. [Explanation of symbols]

[0088] 1. Lubricating oil cleaner 100 Lubricant Cleaning System 130 Separator inlet line (concentrate supply line, route) 133. Return line (route) of the undiluted solution 135 Means of addition 137 Mixing means 140 Light liquid discharge line (route) 150 Lubricating oil discharge line (route) 190 Working water discharge line 200 institutions 300 Lubricating oil tank (route) 400 Heater AW Ammonia water (heavy liquid) DO stock solution LO Lubricating oil (light liquid) W water

Claims

1. A lubricating oil cleaning system that can purify a raw liquid contaminated with ammonia into lubricating oil, The organization and A lubricating oil purifier separates the raw liquid containing the lubricating oil used in the aforementioned engine into a light liquid which is the purified lubricating oil and a heavy liquid which contains ammonia. A path for supplying the aforementioned stock solution to the lubricating oil cleaner, The system includes an additive means for adding water to the stock solution in the aforementioned pathway. Lubrication oil cleaning system.

2. A heater is provided in the aforementioned path for heating the raw liquid to be sent to the lubricating oil cleaner. The additive means is installed either downstream or upstream of the heater in the path, or both. The lubricating oil cleaning system according to claim 1.

3. A mixing means is provided for mixing the water and the stock solution. The lubricating oil cleaning system according to claim 1 or claim 2.

4. The mixing means is a static mixer provided in the path. The lubricating oil cleaning system according to claim 3.

5. A method for purifying lubricating oil that can purify a raw solution containing ammonia, A water addition step involves adding water to the stock solution containing the lubricating oil used in the engine, in a path for supplying the stock solution to a lubricating oil purifier, The process includes a centrifugal separation step that separates the raw liquid containing the lubricating oil into a light liquid which is the lubricating oil purified by a lubricating oil purifier and a heavy liquid which contains ammonia. Lubrication oil cleaning method.

6. The process includes a mixing step of mixing the water added in the water addition step with the stock solution. The method for cleaning lubricating oil according to claim 5.

7. The process includes a heating step of heating the raw liquid in the aforementioned path. The method for cleaning lubricating oil according to claim 5 or claim 6.

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