Process for reducing injector deposits - Patents.com

Abstract

A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, comprising contacting the fuel composition with a metal-selective membrane disposed in a fuel delivery system, wherein the reduction in such deposits provides increased fuel efficiency and fuel thermal stability, improved engine cleanliness, improved fuel economy, and the potential for reducing the amount of expensive detergents used in the fuel composition.

Description

[Technical field]

[0001] The present invention relates to a process for reducing injector deposits in an internal combustion engine (ICE). [Background technology]

[0002] The accumulation of deposits resulting from the combustion of fuel within the engine reduces the efficiency of further combustion, leading to inefficient use of fuel over the life of the engine. A common problem in diesel engines is the fouling of the injectors, specifically the injector body and injector nozzle. Injector nozzle fouling occurs when the nozzle becomes blocked with deposits from the diesel fuel. Deposits have also been known to occur at the tip of the injector. In addition to these "external" injector deposits at the nozzle hole and injector tip, which lead to reduced flow and power loss, deposits can occur within the injector body and cause further problems. These deposits are sometimes referred to as internal diesel injector deposits, or IDID. IDID includes deposits on the needle seat and upstream within the injector, but excludes deposits in the injector nozzle hole. IDID occurs inside the injector on critical moving parts. IDID can impede the movement of these parts affecting the timing and amount of fuel injection, and can have other undesirable effects. Because modern diesel engines operate under very precise conditions, these deposits can have a significant impact on performance. IDID can cause several issues, including loss of power, engine failure, rough idle, and reduced fuel economy due to suboptimal fuel conditioning and combustion. Initially, users may experience cold starting issues and / or engine running roughness. Eventually, these deposits can lead to a more serious injector sticking. This occurs when the deposits cause part of the injector to stop moving, and subsequently, the injector no longer functions. If one or more injectors stick, the engine may fail completely.

[0003] Fuels, and more specifically fuel compositions, may contain some trace metals. The content of such metals varies depending on various factors, such as the source of the crude oil from which the fuel is made, the type of refining process employed, and the handling, storage, and delivery history of the fuel. One example of this may be metal contamination resulting from storage of the fuel composition in a fuel tank located in the fuel delivery system of a vehicle. Another example may be metal contamination resulting from an oil-lubricated high-pressure pump. It is known that the lubricating oil that coats the walls of the high-pressure pump may contain metals such as zinc and / or calcium, which may pass through the seals of the high-pressure pump and contaminate the fuel in the fuel path of the fuel delivery system. In the field of fuel technology, it is known that the presence of metals adversely affects the thermal stability of the fuel. During combustion, this may result in the phenomenon of fouling, for example, the formation of a gummy substance on the fuel injector. It would therefore be desirable to reduce the metal content of the fuel composition, thereby reducing the formation of deposits in the injectors located in the internal combustion engine of the vehicle.

[0004] The use of membranes, such as polydimethylsiloxane membranes, to separate various metals from hydrocarbon mixtures is known, such an application being described in U.S. Patent No. 5,133,851.

[0005] A more recent patent application describing the use of nanofiltration in connection with fuel refining is US2005 / 119517A.

[0006] U.S. Patent Application No. 2006 / 0156620 discloses a method for reducing deposit formation. The patent application refers to a fuel composition that has been treated with a metal adsorbing or absorbing material to reduce the subsequent formation of deposits. It further discloses that the metal adsorbing or absorbing material may include a polymeric adsorbent or absorbent.

[0007] It is known to position a filter in a kidney loop configuration within a fuel management system. U.S. Patent No. 9,388,777 discloses a kidney loop filtration system for a fuel management system in which the kidney loop system is configured to supply fuel from a tank to a fuel transfer pump. A filter is positioned downstream of the pump to remove impurities or contaminants. Summary of the Invention

[0008] Described herein is a process for reducing injector deposits, particularly internal diesel injector deposits (IDID), in an internal combustion engine fueled by a fuel composition, in which the fuel composition is contacted with metal-selective membranes disposed at various locations within the fuel delivery system.

[0009] According to a first aspect of the present invention, there is provided a process for reducing injector deposits in an internal combustion engine fuelled with a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector disposed in the internal combustion engine to a fuel tank.

[0010] According to a second aspect of the present invention, there is provided a process for reducing injector deposits in an internal combustion engine fuelled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a kidney loop filtration system configured to service a fuel tank.

[0011] According to a third aspect of the present invention, there is provided a process for reducing injector deposits in an internal combustion engine fuelled with a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector to a fuel filter disposed in the internal combustion engine.

[0012] According to a fourth aspect of the present invention, there is provided a process for reducing injector deposits in an internal combustion engine fuelled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a low pressure path of a fuel delivery system configured to supply the fuel composition from a fuel tank to an injector.

[0013] The present invention provides a method for reducing the metal content of a fuel composition, reducing injector deposits, such as internal diesel injector deposits (IDID) in internal combustion engines. Thus, the present invention further provides increased fuel efficiency, increased fuel thermal stability, improved engine cleanliness, improved fuel economy, and the potential for reducing the amount of expensive detergents used in the fuel composition. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram illustrating a fuel delivery system in which a metal selective membrane is disposed in a return path configured to deliver a fuel composition from an injector disposed in an internal combustion engine to a fuel tank. [Diagram 2] FIG. 1 is a block diagram illustrating a fuel delivery system in which a metal selective membrane is disposed in a kidney loop configuration. [Diagram 3] FIG. 1 is a block diagram illustrating a fuel delivery system in which a metal selective membrane is disposed in a return path configured to deliver a fuel composition from an injector disposed in an internal combustion engine to a fuel filter. [Figure 4] FIG. 1 is a block diagram illustrating a fuel delivery system in which a metal selective membrane is disposed in the low pressure path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The object of the present invention is to provide a process for reducing injector deposits in an internal combustion engine fueled by a fuel composition. This object is achieved by removing trace metals from the fuel composition using a non-porous (no pores) or nano-filtration (pores with an average size of at most 5 nm) membrane. Such non-porous and nano-filtration membranes are commonly referred to in the art as dense membranes and function in a similar manner based on the solubility and diffusivity profile of the membrane barrier.

[0016] Thus, in the process of the present invention, trace metals are removed from the fuel composition by membrane separation, the membrane having an average pore size of 0.5 to 5 nm. Preferably, the membrane used in the present invention is resistant to gasoline or diesel fuel compositions. This means that the membrane does not dissolve in the fuel composition that has to be purified.

[0017] The dense membranes used in the present invention may be of the polymeric type. Preferably, the membranes used are hydrophobic, since the streams to be treated are hydrocarbon streams which must be able to pass through the membrane.

[0018] In a preferred embodiment of the present invention, the dense membrane is a polymer membrane. Such polymer membranes are preferably crosslinked to provide the necessary network to avoid dissolution of the membrane when in contact with fuel. In general, crosslinking can be performed in several ways, for example by reaction with a crosslinking agent (chemical crosslinking) and / or by irradiation. Preferably, the membrane layer has a siloxane structure crosslinked by irradiation, as described, for example, in WO-A-9627430. Examples of suitable currently available crosslinked non-porous or nanofiltration membranes are crosslinked silicone rubber-based membranes, among which crosslinked polysiloxane membranes are a particularly useful group of membranes. Such crosslinked polysiloxane membranes are known in the art, for example from US Pat. No. 5,102,551.

[0019] Typically, the polysiloxanes used contain the repeating unit --Si--O--, in which the silicon atoms bear hydrogen or hydrocarbon groups. Preferably, the repeat unit is of formula (I): -Si(R)(R')-O- (I) wherein R and R' may be the same or different and represent hydrogen, halogen, or a hydrocarbon group selected from alkyl, aralkyl, cycloalkyl, aryl, and alkaryl groups.

[0020] Preferably, at least one of the groups R and R' is an alkyl group, more preferably both groups are alkyl groups, most preferably methyl groups. The alkyl groups can also include 3,3,3-trifluoropropyl groups.

[0021] Dense membrane is typically supported on at least one porous substrate layer, which acts as a base layer to provide necessary mechanical strength.Preferably, the porous substrate layer is made of a porous material whose pores have an average size of more than 5 nm.Such porous material can be microporous, mesoporous or macroporous material, such as poly(acrylonitrile), which is usually used for microfiltration or ultrafiltration.

[0022] The thickness of the base layer must be sufficient to provide the necessary mechanical strength. Moreover, the substrate may be supported on a further porous support to provide the necessary mechanical strength. Typically, the thickness of the base layer is 100 μm to 250 μm, preferably 20 μm to 150 μm. When a non-porous membrane is combined with such a base layer, the membrane preferably has a thickness of 0.5 μm to 10 μm, more preferably 1 μm to 5 μm.

[0023] The combination of a thin top membrane layer and a thick porous support layer is often referred to as a composite membrane or thin film composite. The membranes are suitably arranged so that the permeate first flows through the top layer of the membrane and then through the base layer, so that the pressure differential across the membrane forces the top layer against the base layer.

[0024] Suitable porous materials for the base layer with an average pore size of more than 5 nm are poly(acrylonitrile), poly(amideimide)+TiO2, poly(etherimide), polyvinylidene fluoride, and poly(tetrafluoroethylene).Poly(acrylonitrile) is particularly preferred.The preferred combination for use in the present invention is poly(dimethylsiloxane)-poly(acrylonitrile) combination.

[0025] The advantage of using a non-porous membrane over a porous membrane is the absence of clogging effects. This means that the membrane cannot be blocked by larger molecules stuck in the pores. This can happen when using a porous membrane, with the result that it becomes increasingly difficult to regenerate a stable flux. Therefore, for the purposes of the present invention, it is preferred to use a non-porous or dense membrane. Further details of membranes suitable for this application can be found in US Patent Application No. 2010 / 0105959.

[0026] The term "metal" or "trace metal" as used throughout this specification in connection with the present invention refers to metals selected from transition metals, post-transition metals, alkali metals, and alkaline earth metals, and mixtures thereof.

[0027] Generally, in a process for removing metals from a fuel composition by membrane separation, a liquid feed comprising a fuel composition containing trace metals suitably selected from Zn, Cu, Fe, Na, K, Ca, and Mg, and mixtures thereof, is separated by a membrane into a permeate comprising a fuel composition free of trace metals or containing trace metals at concentrations lower than the concentrations of the metals in the feed, and a retentate comprising a fuel composition containing metals at concentrations higher than the concentrations of the metals in the feed.

[0028] In another embodiment of the present invention, the trace metals removed are selected from Zn, Cu, Na, Ca, and mixtures thereof.

[0029] In a particularly preferred embodiment of the present invention, the trace metal removed is Zn.

[0030] The present invention can be used to remove combinations of the trace metals disclosed herein.

[0031] The present invention provides a process for reducing injector deposits in an internal combustion engine fuelled by a fuel composition, preferably the fuel composition comprises gasoline or diesel.

[0032] The process according to the present invention may be applied to a variety of engine types, including, but not limited to, diesel engines, gasoline engines, jet engines, hybrid engines, and low temperature combustion (LTC) engines.

[0033] The processes described herein may be used to remove Zn and / or other metals at any point in the supply chain, which may include, for example, metal selective membranes applied either prior to or during transportation of fuel to a retail station by ship, pipeline, storage truck, and / or tanker, in fuel tanks located at retail stations, during the refueling process for on-the-road vehicles, or any combination disclosed herein.

[0034] 1 shows a block diagram of a first configuration of a vehicle fuel delivery system 101 according to the concepts of the present disclosure. The fuel delivery system may include a fuel tank 1 for holding fuel, a low pressure pump 2 for pumping the fuel to a fuel filter 3 for filtering out larger contaminants that may be present in the fuel before the fuel reaches a high pressure pump 4, a high pressure pump 4 for pumping the fuel through a common rail 5 into fuel injectors 6, and the fuel injectors 6 for injecting the fuel into an internal combustion engine 7. Any excess fuel is transported through a return path 8 which feeds the fuel through a metal selective membrane 9 which removes trace metals from the fuel composition. The permeate is then transported back to the fuel tank and the retentate is captured in a waste tank 10.

[0035] 2 illustrates a block diagram of a second configuration of a vehicle fuel delivery system 102 in accordance with the concepts of the present disclosure. The fuel delivery system may include a fuel tank 1 for holding fuel, a low pressure pump 2 for pumping fuel to a fuel filter 3, a fuel filter 3 for filtering out larger contaminants that may be present in the fuel before the fuel reaches a high pressure pump 4, a high pressure pump 4 for pumping fuel through a common rail 5 into fuel injectors 6, and the fuel injectors 6 for injecting the fuel into an internal combustion engine 7. Any excess fuel is transported via a return path 8, which returns the fuel to the fuel filter 3, thus transporting fuel back into the system. At the same time, fuel can be transferred from the fuel tank 1 to a kidney loop filtration system 11 which includes a fuel pump 12 which pumps the fuel through the kidney loop filtration system 11 and through a metal selective membrane 9 which removes trace metals from the fuel. The permeate is transported back to the fuel tank 1, whilst the retentate is collected in a waste tank 10 whose contents can be disposed of when the vehicle is refuelled or during routine maintenance.

[0036] 3 shows a block diagram of a third configuration of a vehicle fuel delivery system 103 in accordance with the concepts of the present disclosure. The fuel delivery system may include a fuel tank 1 for holding fuel, a low pressure pump 2 for pumping the fuel to a fuel filter 3, a fuel filter 3 for filtering out larger contaminants in the fuel before the fuel reaches a high pressure pump 4, a high pressure pump 4 for pumping the fuel through a common rail 5 into fuel injectors 6, and the fuel injectors 6 for injecting the fuel into an internal combustion engine 7. Any excess fuel is transported through a return path 8 which feeds the fuel through a metal selective membrane 9 which removes trace metals from the fuel composition. The permeate is then transported back to the fuel filter 3 and the retentate is captured in a waste tank 10.

[0037] FIG. 4 illustrates a block diagram of a fourth configuration of a vehicle fuel delivery system 104 according to the concepts of the present disclosure. The fuel delivery system may include a fuel tank 1 for holding fuel, a low pressure pump 2 for pumping the fuel towards a fuel filter 3, a fuel filter 3 for filtering out larger contaminants in the fuel before the fuel reaches a metal selective membrane 9, a metal selective membrane 9 for removing metal contaminants from the fuel before delivering the permeate to a high pressure pump 4, and a waste tank 10 to which the retentate is fed. Alternatively, in situations where the fuel delivery system is under high stress, a valve 13 is closed and the fuel flow is directed through a bypass path 14, bypassing the metal selective membrane and delivering the fuel back to the fuel path. The high pressure pump 4 pumps the fuel through a common rail 5, delivering the fuel into the fuel injectors 6, which inject the fuel into the internal combustion engine 7. Any excess fuel is delivered back to the fuel tank 1 via a return path 8.

[0038] 1 to 4, the arrows indicate the direction of flow of the fuel composition.

[0039] During the permeation process, shear forces are necessary across the surface area of ​​the membrane to ensure stable permeation. Methods for generating such shear forces are disclosed herein. The embodiment of the invention described in FIG. 2 may include a short circuit of a pump 12 utilized to create a cross flow across the surface area of ​​the metal selective membrane 9. This may create sufficient shear forces to ensure a stable permeation process and prevent the induction of concentration polarization effects. Similarly, the embodiment of the invention according to FIG. 3 and FIG. 4 may incorporate a device located at the membrane surface, allowing sufficient fluid dynamics to prevent permeation degradation. Suitably, such a device may be vibratory and / or ultrasonic in nature. EXAMPLES

[0040] Example 1 A diesel feed fraction containing B0 (no biocomponents) was contaminated with zinc neodecanoate, resulting in 5 mg / kg of elemental zinc. The diesel fraction was contacted with a non-porous polydimethylsiloxane (PDMS) membrane layer supported by a porous poly(acrylonitrile) (PAN) layer at a transmembrane pressure of 15 bar and a temperature of 30°C. The flux, permeability, and permeate yield as well as the levels of Zn in the resulting permeate and retentate are shown in Table 1 below, analyses of which were completed by inductively coupled plasma mass spectrometry (ICP-MS). As shown in Table 1, the Zn content of the resulting permeate was less than 0.1 mg / kg and the Zn content of the resulting retentate was 7.8 mg / kg + / - 0.8 mg / kg.

[0041] Example 2 A diesel feed fraction containing B0 (no biocomponents) was contaminated with zinc neodecanoate resulting in 5 mg / kg elemental zinc. The diesel fraction was contacted with a non-porous polydimethylsiloxane membrane layer supported by a porous poly(acrylonitrile) layer at a transmembrane pressure of 15 bar and a temperature of 60°C. The flux, permeability, and permeate yield as well as the levels of Zn in the resulting permeate and retentate are shown in Table 1 below, analysis of which was completed by inductively coupled plasma mass spectrometry (ICP-MS). Table 1 shows that the Zn content of the resulting permeate was less than 0.1 mg / kg and the Zn content of the resulting retentate was 15.7 mg / kg + / - 1.6 mg / kg. [Table 1]

[0042] Consideration Analysis of Table 1 showed low levels of Zn in both permeates. Conditions in Example 2 showed that at higher temperatures (60°C), the level of Zn removed from the feed increased. Additionally, at higher temperatures (60°C), the permeability was 0.19 kg.m -2 .hr -1 .bar -1 to 0.45 kg.m -2 .hr -1.bar -1 showed a significant increase in This specification includes the disclosure of the following inventions. [Item 1] 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector disposed in the internal combustion engine to a fuel tank. [Item 2] Item 2. The process of item 1, wherein the metal selective membrane is selected from a polymer comprising units according to the general formula: -Si(R)(R')-O-, where R and R' represent moieties selected from the group consisting of hydrogen moieties, halogen moieties, alkyl moieties, aryl moieties, cycloalkyl moieties, and aralkyl moieties. [Item 3] 3. The process according to claim 1 or 2, wherein the metal selective membrane is selected from polydimethylsiloxane, poly(3,3,3)trifluoropropylmethylsiloxane, and mixtures thereof. [Item 4] 4. The process according to any one of items 1 to 3, wherein the metal selective membrane is polydimethylsiloxane. [Item 5] 5. The process according to any one of items 1 to 4, wherein the metal is selected from transition metals, post-transition metals, alkali metals, and alkaline earth metals, and mixtures thereof. [Item 6] 6. The process according to any one of items 1 to 5, wherein the metal is selected from Zn, Cu, Fe, Na, K, Ca, and Mg, and mixtures thereof. [Item 7] 7. The process according to any one of items 1 to 6, wherein the metal is selected from Zn, Cu, Ca, and Na, and mixtures thereof. [Item 8] 2. The process of any one of the preceding claims, wherein the metal is Zn. [Item 9] 9. The process according to any one of items 1 to 8, wherein the engine is selected from diesel, gasoline, jet, hybrid, and LTC (low temperature combustion) engines. [Item 10] 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a kidney loop filtration system configured to service a fuel tank. [Item 11] 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector to a fuel filter disposed in the internal combustion engine. [Item 12] A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a low pressure path of a fuel delivery system configured to deliver the fuel composition from a fuel tank to an injector. [Item 13] 10. A process as claimed in any one of the preceding claims, wherein the injector deposits are internal diesel injector deposits (IDID).

Claims

1. 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector disposed in the internal combustion engine to a fuel tank.

2. 2. The process of claim 1, wherein the metal selective membrane is selected from a polymer comprising units according to the general formula: -Si(R)(R')-O-, where R and R' represent moieties selected from the group consisting of hydrogen moieties, halogen moieties, alkyl moieties, aryl moieties, cycloalkyl moieties, and aralkyl moieties.

3. 3. The process of claim 1 or 2, wherein the metal selective membrane is selected from polydimethylsiloxane, poly(3,3,3)trifluoropropylmethylsiloxane, and mixtures thereof.

4. The process of any one of claims 1 to 3, wherein the metal selective membrane is polydimethylsiloxane.

5. The process of any one of claims 1 to 4, wherein the metal is selected from transition metals, post-transition metals, alkali metals, and alkaline earth metals, and mixtures thereof.

6. The process of any one of claims 1 to 5, wherein the metal is selected from Zn, Cu, Fe, Na, K, Ca, and Mg, and mixtures thereof.

7. The process of any one of claims 1 to 6, wherein the metal is selected from Zn, Cu, Ca, and Na, and mixtures thereof.

8. The process of any one of claims 1 to 7, wherein the metal is Zn.

9. The process of any one of claims 1 to 8, wherein the engine is selected from diesel, gasoline, jet, hybrid and LTC (low temperature combustion) engines.

10. 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a kidney loop filtration system configured to service a fuel tank.

11. 1. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a return path of a fuel delivery system configured to deliver the fuel composition from an injector to a fuel filter disposed in the internal combustion engine.

12. A process for reducing injector deposits in an internal combustion engine fueled by a fuel composition, the process comprising contacting the fuel composition with a metal selective membrane disposed in a low pressure path of a fuel delivery system configured to deliver the fuel composition from a fuel tank to an injector.

13. A process according to any one of claims 1 to 8 and 10 to 12, wherein the injector deposits are internal diesel injector deposits (IDID).

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