H2ice lubricants with improved hydrogen solubility

Abstract

A study of how lubricant additives impact hydrogen solubility is used to develop specialized lubricants for hydrogen internal combustion engine (H2ICE) applications to mitigate hydrogen leakage. An exemplary lubricant of a lubricating viscosity and formulated for a hydrogen internal combustion engine may include a base oil and a surfactant, wherein the hydrogen solubility of the lubricant is at least 7% as measured by Ostwald coefficient.

Description

Atty Docket No. : 47075-03658H2ICE Lubricants with Improved Hydrogen SolubilityTECHNICAL FIELD

[0001] The invention relates to specialized lubricants for hydrogen internal combustion engine (H2ICE) applications to mitigate hydrogen leakage.BACKGROUND

[0002] Given the pressing issues of fossil fuel scarcity and increasing human-induced greenhouse gas emissions, there is a growing interest in exploring alternative energy sources and technologies. One prominent area of focus involves researching and developing renewable and sustainable alternative fuels while simultaneously improving the energy efficiency of engines. Hydrogen stands out as a leading contender to meet future energy demands and plays a central role in government energy strategies. Hydrogen offers several advantages over conventional petroleum fuels. Its mass-based heating value is three times higher, and it produces significantly fewer harmful emissions in H2ICE applications, which addresses one of the major drawbacks of fossil fuels. Consequently, hydrogen has the potential to become a sustainable fuel, reducing global reliance on fossil fuel resources and decreasing pollutant emissions from transportation.

[0003] However, challenges remain in adopting hydrogen as fuel for H2ICE, with hydrogen leaks to crankcase being a significant concern. Hydrogen's small and lightweight molecular structure makes it more prone to unintentional release. In addition, its flammable nature and ability to form explosive mixtures with air categorize it as a hazardous substance, necessitating precautions against leaks and potential consequences. Hydrogen leaks can lead to explosive mixtures with air, underscoring the need for preventive measures and reliable detection systems to ensure safe hydrogen handling. While recent research has predominantly focused on improving equipment, such as building the detection system or setting up the hydrogen absorption box withAtty Docket No. : 47075-03658 the engine, limited attention has been given to the role of lubricants in addressing hydrogen leakage.SUMMARY

[0004] The Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0005] An exemplary lubricant of a lubricating viscosity and formulated for a hydrogen internal combustion engine may include a base oil and an additive such as surfactant, wherein the hydrogen solubility of the lubricant is at least 7% as measured by Ostwald coefficient.

[0006] Other methods, features and / or advantages is, or will become, apparent upon examination of the following figures and detailed description. It is intended that all such additional methods, features, and advantages be included within this description and are protected by the accompanying claims.BRIEF DESCRIPTION OF DRAWINGS

[0007] FIG 1 is a graph demonstrating a correlation between base oil density and hydrogen solubility according to one aspect of the invention.

[0008] FIG 2 is a graph depicting hydrogen solubility in Group II base oil and with different additives according to an aspect of the invention.

[0009] FIG 3 is a graph depicting hydrogen solubility in Group II base oil with various types of surfactants. (Note: 0.5 wt% is the maximum solubility content for CTAB. SDS: sodium dodecyl sulfate, SDBS: sodium dodecylbenzenesulfonate, CTAB: hexadecyltrimethylammonium bromide, DGME: decaethylene glycol monododecyl ether)Atty Docket No. : 47075-03658

[0010] FIG 4 is a graph depicting hydrogen solubility in Group II base oil with varying SDBS content.DETAILED DESCRIPTION

[0011] Surprisingly, the solubility of hydrogen in lubricants remains an understudied area. This study investigated how lubricant additives impact hydrogen solubility. Such additives will assist in developing specialized lubricants for H2ICE applications able to mitigate hydrogen leakage.Definitions

[0012] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the present specification, including definitions, will control. For example, the term hydrogen may refer to H2 gas and H2ICE refers to a hydrogen internal combustion engine (H2ICE).

[0013] Unless otherwise specified, “a,” “an,” “the,” “one or more of,” and “at least one” are used interchangeably. The singular forms “a,” “an,” and “the” are inclusive of their plural forms.

[0014] The recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 0.5 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0015] The term “about,” when referring to a value or to an amount of mass, weight, time, volume, concentration, or percentage is meant to encompass variations of ±1% from the specified amount. The term “about X wt. %” can be taken to means that the wt. % may vary within 1 wt. % of the X reference numeral unless otherwise specified. That is if X is 5 wt. %, and thus about 5 wt. % may encompass between 4 wt. % and 6 wt % unless otherwise described as encompassing a different range.Atty Docket No. : 47075-03658

[0016] The terms “comprising” and “including” are intended to be equivalent and open-ended. The phrase “consisting essentially of’ means that the composition or method may include additional ingredients and / or steps, but only if the additional ingredients and / or steps do not materially alter the basic and novel characteristics of the claimed composition or method. The phrase “selected from the group consisting of’ is meant to include mixtures of the listed group.

[0017] Moreover, the present disclosure also contemplates that in some aspects, any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed singularly or in any combination.

[0018] Weight percent: All weight (and mass) percents expressed herein (unless otherwise indicated) are based on overall composition weight.Hydrogen Solubility

[0019] According to an aspect of the invention, a lubricant is formulated that is capable of absorbing or solubilizing hydrogen gas. A typical measure of this hydrogen solubility is ASTM D2779 (Standard Test Method for Estimation of Solubility of Gases in Petroleum Liquids) and provides results as an Ostwald coefficient (%).Base oil

[0020] A base oil of lubricating viscosity is an integral part of lubricant composition providing performance and characteristics benefits. A base oil in the present context is a bio-derived oil, mineral oil, synthetic or a combination of all. The viscosity of the oil ranges from about 2 mm2 / s to about 40 mm2 / s, especially from about 4 mm2 / s to about 20 mm2 / s as measured at 100°C.Atty Docket No. : 47075-03658

[0021] The base oil of lubricating viscosity may be selected from the group consisting of mineral oils (Group I, II or III oils), polyalphaolefins (Group IV oils), all other base oils not included in Group I, II, III or IV (Group V oils), such as polymerized and interpolymerized olefins, alkyl naphthalenes, alkylene oxide polymers, silicone oils, phosphate esters and carboxylic acid esters.

[0022] Group I to Group IV base oils as definitions for the base oil of this invention are the same as those found in the American Petroleum Institute (API) publication "Engine Oil Licensing and Certification System", Industry Services Department, Fourteenth Edition, December 1996, Addendum 1, December 1998.

[0023] The base oil in the invention will normally comprise the major amount of the composition. Thus it will be at least 50% by weight of the composition, such as 51 to 99%.

[0024] In some aspects of the invention, base oils may be modified themselves and / or also include additives to enhance the solubility of the final lubricant formulation for hydrogen gas. Surfactant

[0025] According to some aspects of the invention, a surfactant is added to the base oil to increase hydrogen gas solubility of the lubricant. The surfactant may be an anionic surfactant, a cationic surfactant, or a nonionic surfactant, such as SDS (sodium dodecyl sulfate), SDBS (sodium dodecylbenzenesulfonate), CTAB (hexadecyltrimethylammonium bromide), or DGME (decaethylene glycol monododecyl ether). In some aspects the surfactant is SDBS. In some aspects the additive is present in the final formulation in an amount between about 0.5 wt % and 2.5 wt %. In some, the surfactant is SDBS and is present in an amount of about 1.5 wt%.AdditivesAtty Docket No. : 47075-03658

[0026] In some aspects, lubricants formulated with at least one additive that may include corrosion inhibitors, organic corrosion inhibitors, antioxidant, dispersants, detergents, antioxidants, anti-wear agents, viscosity modifiers, pour point depressants, friction modifiers, antifoaming agents, demulsifiers, or seal swell agents are used in amounts generally encountered in the art, for example between about 0.01 wt % and about 20 wt %, or between 1 wt % and about 20 wt %.

[0027] EXAMPLES

[0028] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to preferred aspects and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alteration and further modifications of the disclosure as illustrated herein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.

[0029] Example 1: A correlation between base oil and hydrogen solubility

[0030] Lubricants typically consist of base oils and additives. Initial investigations have uncovered a correlation between base oil and hydrogen solubility, particularly in Group I to Group IV base oils. As shown in FIGI, hydrogen solubility in base oil (Group I to Group IV) with varying densities. (Ostwald coefficient means the volume of gas dissolved per volume of the liquid.) It showed hydrogen solubility would decrease as the base oil density increased. However, it is noteworthy that in the case of Group V base oils with distinct compositions, this correlation does not necessarily apply. Even when these oils exhibit higher density, their hydrogen solubility remains surprisingly unaffected.

[0031] Example 2: Effect of additives on hydrogen solubilityAtty Docket No. : 47075-03658

[0032] Subsequent experiments have explored various additives, including polymers with nitrogen group, graphene, and surfactants, to enhance hydrogen solubility. Surprisingly, surfactants have demonstrated a significant impact on hydrogen solubility compared to reference Group II base oils, rising from 6.0% to 7.2% (FIG 2). Upon calculation, it became apparent that the base oil's capacity for hydrogen absorption stood at a modest 0.070 mL Fh / g, whereas the surfactant exhibited an impressive capability of up to 0.634 mL Fh / g. This enhancement could be attributed to surfactants' ability to reduce surface tension at the liquid-gas interface, promote micelle formation, or increase surface area, thereby increasing hydrogen solubility.

[0033] Example 3: Effect of surfactants on hydrogen solubility

[0034] Further research involving various surfactant types (FIG 3), such as anionic surfactant SDS: sodium dodecyl sulfate), anionic surfactant (SDBS: sodium dodecylbenzenesulfonate), cationic surfactant (CT AB: hexadecyltrimethylammonium bromide), and nonionic surfactant (DGME: decaethylene glycol monododecyl ether), has identified SDBS as a promising candidate.

[0035] Example 4: Effect of surfactant concentration on hydrogen solubility

[0036] Optimizing the SDBS content at 1.5 wt% has shown impressive results (FIG 4), withSDBS exhibiting a hydrogen absorption capacity of up to 2.88 mLEb / g.

[0037] Taken together the examples demonstrate, according to one aspect of the invention, a method of determining the hydrogen solubility trend for base oils and / or various additives for use as lubricants is provided. According to an aspect of the invention, the hydrogen solubility trend aids in selecting base oils and / or lubricants for H2ICE lubricant applications. In another aspect of the invention, a method to determine the hydrogen solubility of a particular base oil or base oil and additive combination is provided.Atty Docket No. : 47075-03658

[0038] The complete disclosure of all patents, patent applications, and publications, and electronically available material cited herein are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.

Claims

Atty Docket No. : 47075-03658CLAIMS:

1. A lubricant of a lubricating viscosity and formulated for a hydrogen internal combustion engine comprising: a base oil; and a surfactant, wherein the hydrogen solubility of the lubricant is at least 7% as measured by the Ostwald coefficient.

2. The lubricant of claim 1, further comprising an additive that is an antioxidant agent, an antiwear agent, an extreme pressure agent, a detergent, a dispersant, an antifoamer, an anti-rust agent, a friction modifiers, a corrosion inhibitor, or a pour point depressant.

3. The lubricant of claim 1, wherein the base oil is a Group II base oil.

4. The lubricant of claim 1, wherein the base oil has a viscosity of between 0.70 g / cm3and0.76 g / cm3.

5. The lubricant of claim 1, wherein the surfactant is an anionic surfactant.

6. The lubricant of claim 1, wherein the surfactant is sodium dodecylbenzenesulfonate.

7. The lubricant of claim 1, wherein the surfactant is present in an amount between 0.5 wt % and 2.5 wt %.

8. The lubricant of claim 1, wherein the surfactant is present in an amount of 1.5 wt%.

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