GB2245588A - Reduction of colour and sediment formation in fuel oils - Google Patents

Abstract

Certain triazines and diaminomethanes, that are conveniently made by condensing formaldehyde and a primary or secondary amine, are useful in reducing colour and sediment formation in fuel oils.

Description

"Fuel Oil Compositions This invention relates to fuel oil compositions and more especially to fuel oil compositions containing cracked components which are stabilized against sediment formation and colour development during storage. Cracked components are frequently included to give higher yields of diesel fuel and heating oil.

However, when diesel and heating oils containing cracked components are stored at ambient or elevated temperatures in air they become discoloured and precipitate sludge or sediment.

It is clear that the problem of discoloration and sediment formation is exacerbated by the presence of cracked components in the fuel. This is demonstrated by the results in Table 1 which show the amount of sediment formed and the colour change when various fuel blends are tested in the AMS 77.061 accelerated stability test.

Published research (see, for example, Offenhauer et. al, Industrial and Engineering Chemistry, 1957, Volume 49, page 1265, and the Proceedings of the 2nd International Conference on the Long Term Stability of Liquid Fuels, San Antonio, Texas, published October 1986) suggests that discoloration and sediment result from the oxidation of sulphur and nitrogen compounds present in the fuel. The analysis of cracked components is consistent with this. The results in Table 2 show that cracked components contain significantly larger quantities of nitrogen and sulphur than straight distillates. Also, the addition of nitrogen and sulphur compounds to a stable straight distillate causes an increase in both sediment and colour in the AMS 77.061 test (Table 3) with the worst result being obtained when both nitrogen and sulphur compounds are present in the fuel.

In British Patent Specification No. 798062, it has been proposed to improve the colour stability and resistance to sedimentation of a distillate fuel oil by the addition thereto of hexahydrotriazines substituted at each nitrogen atom by a linear aliphatic hydrocarbon radical having from 8 to 18 carbon atoms.

In British Specification No. 1325913, it was proposed to protect jet and similar hydrocarbon fuels against attack by microorganisms by the addition of the condensation product of an aldehyde and a primary or secondary alkanolamine. In a related patent, No. 1374340, such fuels, and cutting oils, are protected against attack by microorganisms by the addition of condensation products of aldehydes and etheramines, while in No. 1392171 protection is afforded by N-substituted hexahydrotriazines in which the substituent is a cycloalkyl group or an alkyl group having up to 6 carbon atoms.

It has now been found that sediment and colour formation may be substantially reduced in fuel oils, for example, diesel fuels or heating fuels, especially those containing cracked components, by the addition of certain compounds that may be regarded as the condensation products of an amine with formaldehyde, and are conveniently made by such a condensation reaction.According to this invention fuel oil compositions comprise a base fuel, which may contain cracked components, and (i) a triazine of the formula

in which at least one of R11 R2 and R3, which may be the same or different, represents (a) a cycloaliphatic or alkylcycloaliphatic radical having at least 7 carbon atoms, or an alkenyl radical, optionally substituted by one or more amino groups; (b) an aromatic radical, optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group;; (c) a group of the formula -(R4NR5) mR4NR5R6 wherein m represents an integer from 0 to 10, R4 represents an optionally substituted alkenylene, cycloalkenylene, alkylene, or cycloalkylene radical, and R5 and R6, which may be the same or different, represent hydrogen or an alkyl, cycloalkyl, alkenyl, or cycloalkenyl group, or an aromatic radical optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group; and the other or others of R1, R2, and R3, when it is or they are not as defined above, is or each independently is an aliphatic radical, preferably one having 1 to 6 carbon atoms, or a cycloaliphatic radical, having 5 to 6 carbon atoms, optionally substituted by one or more secondary or tertiary amino groups; a hydroxyaliphatic radical optionally interrupted by one or more oxygen atoms; or an aliphatic radical interrupted by oxygen atoms, the triazine advantageously containing at least 10, and preferably at least 12 carbon atoms, or (ii) a diaminomethane in which the first amino group is of the formula -NR8R9 in which (d) R8 and R91 which may be the same or different, represent an aliphatic, cycloaliphatic, or non aromatic heterocyclic radical, which may optionally carry one or more secondary or tertiary amino groups or in which (e) R8 and R9 together with the nitrogen atom form a ring which optionally contains a further heteroatom or atoms, e.g., nitrogen, oxygen, or sulphur, or is of the formula -N(R10) (R4NR5)nR4NR5R6 wherein R4, R5, and R6 have the meanings given above and n is an integer from 0 to 10, and R10 may also represent (R4NR5)nR4NR5R6 or may represent an alkyl, cycloalkyl, alkenyl or cycloalkenyl group, and the second amino group has one of the meanings given for the first or is of the formula NR12R13, in which each of R12 and R13 represent a hydroxyaliphatic radical optionally interrupted by one or more oxygen atoms or one of R12 and R13 has that meaning and the other represents an aliphatic radical, or in which one of R12 and R13 represents an aliphatic radical and the other represents an aromatic radical, the diaminomethane advantageously having at least 6, preferably at least 8 carbon atoms.

It is within the scope of the invention to use a mixture of two or more triazines, of two or more diamino methanes, or of one or more triazines and one or more diaminomethanes.

As examples of suitable primary amines from which at least one of the groups #NRl#, -NR2- and -NR3- in the triazine is notionally or actually derived there may be mentioned C-substituted cyclohexylamines, e.g., 2-methylcyclohexylamine and its isomers, aniline and C-substituted anilines, e.g., 2-methyl-aniline and its isomers, 1- and 2-naphthylamine, ethylenediamine, 1,2and 1,3-propylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-methylethylenediamine, N,N-dimethylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyl-1,4butylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, and C-substituted diaminocyclohexanes.

As examples of suitable secondary amines from which the group -NR8R9 in the diaminomethane may be notionally or actually derived, there may be mentioned dimethylamine, diethylamine, N-methylethylamine, N-methylpropylamine, N-methylbutylamine, N-methyldecylamine, din-propylamine, di-n-butylamine, N-methylcyclohexylamine, or the secondary amines derived from coconut and hydrogenated tallow oils, N,N,N'-trimethylethylenediamine, N,N-dimethyl-N'-ethylethylenediame, N,N,N'-trimethyl-l,3- propylenediamine, piperazine, morpholine, and C-substituted piperazines and morpholines.

As examples of primary amines which may provide the notional or actual origin for one or two of the groups -NR1-, -NR2-, and -NR3-, when they are other than as required for the composition of the invention there may be mentioned methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, iso-butylamine, secbutylamine, t-butylamine, the normal pentylamine, hexylamine, decylamine and their isomers, the primary amines derived from coconut and hydrogenated tallow oils, ethanolamine, and amines of the formula H2N [ R4O)mH, wherein R4 and m have the meanings given above, e.g., H2N(C2H4O)mH and H2N(C3H6O)mH or 3-amino-l-propanol.

As examples of secondary amines which may provide the notional or actual origin for NR12R13 there may be mentioned N-methylaniline, N-methyl-l-naphthylamine or an amine of the formula HN(R11) [ R4O)mH, wherein R11 represents tR4O ] mH or an alkyl, alkenyl, cycloalkyl or cycloalkenyl group, and R4 and m have the meanings given above, e.g., N( [ C2H4O##H)2 and N( [ C3H6O)mH)2, diethanolamine, and di-1-propanolamine.

The present invention also provides the use of a diaminomethane or a triazine to inhibit chemically initiated colour and sediment formation in a fuel oil, in which the diaminomethane or triazine is one as defined above for the composition of the invention, or being a diaminomethane, is one in which, in NR8R9, R8 represents an aliphatic radical and R9 represents an aromatic radical or R8 and R9 each represent a hydroxy aliphatic radical; or, being a triazine, is one in which at least one of R1, R2 and R3 represents a hydroxyaliphatic radical optionally interrupted by oxygen atoms, an aliphatic radical interrupted by oxygen atoms, or an alkyl, alkenyl, cycloalkyl, or cycloalkenyl radical having up to 6 carbon atoms.

Examples of suitable additional substituents for the triazines are as given above for -NR1- -NR2- and -NR3when they are other than as required for the compositions of the invention and, for the diaminomethanes, the secondary amines given as examples of sources for NR12R13 are appropriate.

The additive compounds may conveniently be manufactured by condensation of a primary or secondary amine with formaldehyde, which may be used in any of the usual forms in which formaldehyde is supplied, e.g., in gaseous form, aqueous solution (formalin) or solid polymer (trioxane or paraformaldehyde).

When the amine is a primary amine, the preferred method is by the direct reaction of the amine and formaldehyde in a molar ratio of from 0.5:1 to 1.5:1, advantageously in equimolar proportions. When the amine is secondary, the molar ratio of amine to formaldehyde is advantageously within the range of from 1:1 to 3:1, the ratio preferably being 2:1.

It is not essential for the reaction to take place in solution, but it is preferred to use a hydrocarbon solvent, e.g., hexane, heptane, toluene or xylene. The reaction mixture is heated to reflux and the water produced by the reaction is collected in a Dean and Stark trap. When evolution of water ceases, indicating completion of the reaction, the solvent is removed by distillation, preferably under vacuum.

The condensation product may be employed in the form of an additive concentrate, comprising the product in solution in fuel oil, or in a solvent miscible with fuel oil, for example, xylene and toluene, or hydrocarbon mixtures used as lubricant basestocks. The proportion of diluent per part of oil-soluble condensation product is normally 0.1 to 100 parts, preferably 0.2 to 20 parts, by weight.

The fuel oil composition advantageously comprises a minor proportion by weight of the condensation product, preferably less than 1t by weight, more preferably from 0.0005 to 0.1%, more usually 10 to 500 ppm, and especially 2 to 200 ppm.

The cracked component in the fuel oil which leads to the undesirable colour formation and sediment is generally obtained by cracking of heavy oil and may be fuel oil in which the main constituent is a fraction obtained from a residual oil after removal of distillate oil by distillation, or by thermal cracking or catalytic treatment of heavy distillate oil obtained by distillation. The cracked component may then be distilled further by atmospheric or vacuum distillation (called cracked fraction hereinafter), or the cracked fraction may be mixed with a fraction obtained by direct ordinarypressure distillation or reduced-pressure distillation (called direct-distillation fraction hereinafter).

Typical methods available for the thermal cracking are visbreaking and delayed coking. Alternatively the fuels may be obtained by catalytic cracking, the principal methods being moving-bed cracking and fluidized bed cracking. After cracking, the distillate oil is extracted by normal or vacuum distillation, the boiling point of the distillate oil obtained usually being 60 500 C, and is a fraction called light-cycle oil, preferably corresponding to the boiling point range of light oil of 150-4000C. Compositions composed entirely of this fuel or fuels which are mixtures of the cracked fraction and normal distillates may be used in the present invention.

The proportion by weight of direct-distillation fraction and cracked fraction in a fuel oil composition which is a mixture may vary considerably, but is usually 1:0.03 - 1:2 and preferably 1:0.05 - 1:1. Typically the content of cracked fraction is 5-97%, and is preferably 10-50%, based on the weight of the composition.

The present invention accordingly also provides a fuel oil composition comprising a distillate fraction and a cracked fraction. and the amine/aldehyde condensation product defined above.

The fuel oil compositions of the present invention may contain other additives such, for example, as antioxidants, anticorrosion agents, fluidity improvers, agents absorbing ultraviolet radiation, detergents, dispersants and cetane improvers in small amounts (for example, usually less than 2% based on the weight of the composition).

The following examples illustrate the invention: In the tables at the end of the examples, Table 1 shows the effect on sediment and colour in the AMS 77.061 test of blending different amounts of a straight distillate fuel (Fuel A), containing 50 ppm nitrogen and 0.24% sulphur, with an unhydrofined catalytically cracked gas oil (Fuel B) containing 695 ppm nitrogen and 1.11% sulphur.

Table 2 shows the nitrogen and sulphur contents of various fuels.

Table 3 shows the effect on colour and sediment of doping the stable fuel (A) with compounds containing nitrogen and sulphur.

Table 4 shows the effect on sediment and colour in the AMS 77.061 test of adding 200 ppm of amine/formaldehyde condensation products to a fuel.

Example 1 The Reaction of di-n-butylamine with Paraformaldehvde Di-n-butylamine (129 g:1.0 mole) was dissolved in toluene (200 ml). The solution was stirred and paraformaldehyde (15 g: 0.5 moles) was added. The reaction mixture was heated to reflux and the water evolved (8.5 ml: theory 9.0 ml) collected in a Dean and Stark trap. When no more water was formed, the solvent was removed by heating at 1500C under vacuum. The TBN of the final product was measured.

Other products were synthesized using the same method with different secondary amines: the results are shown below: Amine Water evolved/ml TBN (mq KOH/a) Di-n-butylamine 8.5 (9.0)(a) 403 (415)(a) Morpholine 8.5 (9.0) 585 (602) Diethanolamine 8.5 (9.0) 493 (505) Arineen(b) 2-HT 4.0 (4.5) 108 (111) (a) theoretical value in brackets (b) Armeen 2-HT is a trade mark for a di (hydrogenated tallow) amine Example 2 The Reaction of n-octvlamine with Paraformaldehyde n-Octylamine (129 g; 1.0 mole) was dissolved in 200 ml of toluene. The solution was stirred and paraformaldehyde (30 g; 1.0 mole) was added. The reaction mixture was heated and the water evolved (17.1 ml; theory 18.0 ml) collected in a Dean & Stack trap.When water evolution ceased, the solvent was removed by heating to 1500C under vacuum. The TBN of the final product was measured.

Other products were synthesized by the same method using different amines. The results are shown below: Amine Water evolved/ml TBN (mg KOH/g) DMAP(d) 15.0 (18.0)(a) 815 (483)(a) DETA(e) 19.0 (18.0) 919 (1340) Primene 81-R(f) 18.0 (18.0) 260 (284) (d) DMAP - dimethylaminopropylamine (e) DETA - diethylenetriamine (f) Primene 81-R - a C12 tertiary alkyl primary amine.

Example 3 Sediment and colour formation in fuel oils is largely a result of the presence, and reaction, of nonbasic heterocyclic nitrogen compounds, present in greatest proportions when the fuel contains cracked components, and of sulphonic acids, resulting from oxidation of aromatic thiols in the fuel. The chemical reactions that the present invention is primarily concerned to inhibit are those caused by direct reaction of fuel components with oxygen, rather than those resulting from biological activity, where oxidation reactions are mediated by a living cell or by an enzyme formed by a living cell.

To test the ability of the amine formaldehyde condensation products to inhibit colour and sediment formation, a stable Japanese fuel having an initial colour of 0.5, as measured by ASTM D1500, was doped with 100 ppm of 2,5-dimethylpyrrole and 50 ppm of a commercially available alkylaryl sulphonic acid. Different samples of the fuel were treated with one of the products described in Examples 1 and 2, at a treat rate of 200 ppm, and stored in darkness at 400C for 28 days, then filtered, the sediment was weighed, and the colour of the filtrate measured. The results are shown in Table 4 below.

Table 1 The Effect of Fuel Com#osition on Sediment and Colour in the AMS 77.061 Accelerated Stability Test

Fuel A Fuel B ≈ Sediment Colour (a) wt. % wt.% mg/100 ml 100 0 0.14 + 0.09 #0.5, < 0.5, < 0.5 80 20 0.61 + 0.13 #1.0, 1.0, 1.0 60 40 } 1.12 + 0.10 , #1.0,#1.0,#1.0,#1.0 40 60 1.80 + 0.04 2.0, 2.0 40 20 80 2.10 + 0.10 #2.0, x2.0 0 100 2.90 6.0 (a) Colour change (ASTM D1500 test) Table 2 The Nitrogen and Sulphur Contents of Various Fuels

Type of Fuel Nitrogen (ppm) Sulphur (%) Unhydrofined CCGO 695 1.11 " ,. 650 1.70 Straight distillate 50 0.24 " " 70 0.25 " " 97 0.23 " " 128 0.24 Table 3 Effect of doping with dimethyl pyrrole (DMP) and a sul#honic acid (SA) on the stability of a straight distillate fuel in the AMS 77.061 test

DMP SA Sediment Colour ppm(a) ppm(b) (mg/100 ml) Before After (c) Nil Nil 0.06,0.10 < 0.5 < 1.0 0.5 Nil 50 0.02,0.00 < 0.5 < 1.5 1.0 < 0.5 < 1.5 1.0 50 Nil 0.76,0.59 < 0.5 < 1.0 0.5 < 0.5 < 1.0 0.5 50 50 1.06,1.01 < 1.5 < 3.0 11.5 < 1.5 < 3.0 1.5 (a) 2,5-dimethylpyrrole (b) A commercially available alkyl-aryl sulphonic acid having a standard acid number of approximately mg KOH/g of acid.

(c) colour change (ASTM D1500) Table 4 The Effect of Amine/Formaldehvde Condensation Products on Fuel Stability

Additive Sediment Colour (mg/100 g of fuel) (ASTM D1500) None (3.58 + 0.37) 2.5 to 3.5 Primene 81-R/CH2O 5.98 < 1.5 Diethanolamine/CH20 3.12 1.5 Armeen 2HT/CH2O 3.08 1 1.5 Di-n-butylamine/CH2O 2.02 1.5 DETA/CH2O 1.54 I < 1.0 Morpholine/CH2O | 0.34 0.5 DMAP/CH2O 0.14 < 1.5

Claims (14)

CLAIMS:

1. The use to inhibit chemically initiated colour and sediment formation in a fuel oil of (i) a triazine of the formula

in which at least one of R1, R2 and R3, which may be the same or different, represents an alkenyl, cycloaliphatic or alkylcycloaliphatic radical having at least 7 carbon atoms, optionally substituted by one or more amino groups; an aromatic radical, optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group; a hydroxyaliphatic radical optionally interrupted by one or more oxygen atoms; an aliphatic radical interrupted by oxygen atoms; an alkyl, alkenyl; cycloalkyl or cycloalkenyl radical having up to 6 carbon atoms; a group of the formula - (R4NR5)mR4NR5R6 wherein m represents an integer from 0 to 10, R4 represents an optionally substituted alkenylene, cycloalkylene, cycloalkenylene or alkylene radical, and R5 and R6, which may be the same or different, represent hydrogen or an alkyl, cycloalkyl, alkenyl, or cycloalkenyl group, or an aromatic radical optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group; and the other or others of R1, R2, and R3, when it is or they are not as defined above, is or each independently is a cycloaliphatic radical having 5 to 6 carbon atoms, or an aliphatic radical, optionally substituted by one or more secondary or tertiary amino groups; or of (ii) a diaminomethane in which the first amino group is of the formula -NR8R9 in which R8 and R9, which may be the same or different, represent an aliphatic, cycloaliphatic, or non-aromatic heterocyclic radical, which may optionally carry one or more secondary or tertiary amino groups; or in which R8 and R9 together with the nitrogen atom form a ring which optionally may contain a further hetero atom or atoms; or in which one of R8 and R9 represents an aliphatic radical and the other represents an aromatic radical; or in which R8 and R9 each represent a hydroxyaliphatic radical; or is of the formula -N(R1O)(R4NR5)nR4NR5R6 wherein R4, R5, and R6 have the meanings given above and n is an integer from 0 to 10, and P10 also represents (R4NR5)nR4NR5R6 or an alkyl, cycloalkyl, alkenyl or cycloalkenyl group, and the second amino group has one of the meanings given for the first or is of the formula NR12R131 in which each of R12 and R13 represent a hydroxyaliphatic radical interrupted by one or more oxygen atoms or one of R12 and R13 has that meaning and the other represents an aliphatic radical, or in which one of R12 and R13 represents an aliphatic radical.

2. A fuel oil#composition comprising a base fuel and (i) a triazine of the formula

in which at least one of R1 R2 and R3, which may be the same or different, represents a cycloaliphatic or alkylcycloaliphatic radical having at least 7 carbon atoms, or an alkenyl radical, optionally substituted by one or more amino groups; an aromatic radical, optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group; a group of the formula -(R4NR5) mR4NR5R6 wherein m represents an integer from 0 to 10, R4 represents an optionally substituted alkenylene, cycloalkylene, cycloalkenylene or alkylene radical, and R5 and R6, which may be the same or different, represent hydrogen or an alkyl, cycloalkyl, alkenyl, or cyclo alkenyl group, or an aromatic radical optionally substituted by an alkyl, cycloalkyl, alkenyl or cycloalkenyl group; and the other or others of R1, R2, and R3, when it is or they are not as defined above, is or each independently is a cycloaliphatic radical, having 5 or 6 carbon atoms; or an aliphatic radical, optionally substituted by one or more secondary or tertiary amino groups; a hydroxyaliphatic radical optionally interrupted by one or more oxygen atoms; or an aliphatic radical interrupted by oxygen atoms, or (ii) a diaminomethane in which the first amino group is of the formula -NR8R9 in which R8 and R9, which may be the same or different, represent an aliphatic cycloaliphatic, or non-aromatic heterocyclic radical, which may optionally carry one or more secondary or tertiary amino groups or in which R8 and R9 together with the nitrogen atom form a ring which optionally may contain a further heteroatom or atoms; or is of the formula -N(R10) (R4NR5)nR4NR5R6 wherein R4, R5, and R6 have the meanings given above and n is an integer from 0 to 10, and R10 also represents (R4NR5)nR4NR5R6 or an alkyl, cycloalkyl, alkenyl or cycloalkenyl group, and the second amino group has one of the meanings given for the first or is of the formula NR12R13, in which each of R12 and R13 represent a hydroxyaliphatic radical optionally interrupted by one or more oxygen atoms or one of R12 and R13 has that meaning and the other represents an aliphatic radical, or in which one of R12 and R13 represents an aliphatic radical and the other represents an aromatic radical.

3. The invention as claimed in claim 1 or claim 2, wherein the triazine contains at least 10 carbon atoms or the diaminomethane contains at least 6 carbon atoms.

4. The invention as claimed in any one of claims 1 to 3, wherein a triazine is employed, and the amine from which at least one of the groups -NR1-, -NR2and -NR3- is derivable is a C-substituted cyclo hexylamine, aniline, a C-substituted aniline, 1- or 2-naphthylamine, ethylenediamine, 1,2- or 1,3-propylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-methylethylenediamine, N,N-dimethylethylenediamine, N,N-dimethyl-1,3-propylenediamine, N,N-dimethyl-1,4butylenediamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, or a C-substituted diaminocyclohexane.

5. The invention as claimed in any one of claims 1 to 4, wherein a triazine is used, and each of the groups -NR1-, -NR2-, and NR3- is identical.

6. The invention as claimed in any one of claims 1 to 3, wherein a diaminomethane is employed, and wherein the amine from which the group -NR8R9 is derivable is dimethylamine, diethylamine, N-methylethylamine, N-methylpropylamine, N-methylbutylamine, Nmethyldecylamine, di-n-propylamine, di-n-butylamine, Nmethylcyclohexylamine, a secondary amine derived from coconut or hydrogenated tallow oil, N,N,N'-trimethylethylenediamine, N,N-dimethyl-N'-ethylethylenediame, N,N,N'-trimethyl-1,3-propylenediamine, piperazine, morpholine, or a C-substituted piperazine or morpholine.

7. The invention as claimed in any one of claims 1 to 6, wherein the triazine or the diaminomethane is used in a proportion of from 5 to 1000 ppm based on the total weight of the fuel oil.

8. The invention as claimed in claim 7, wherein the proportion is 10 to 500 ppm.

9. The invention as claimed in claim 7, wherein the proportion is 20 to 200 ppm.

10. The invention as claimed in any one of claims 1 to 9, wherein the fuel oil contains a cracked component.

11. The invention as claimed in claim 10, wherein the fuel contains a direct-distillation fraction and a cracked fraction in a ratio between 1:0.03 and 1:2.

12. The invention as claimed in claim 1, substantially as described in any one of the individual runs in Example 3 herein.

13. A concentrate comprising a triazine or diaminomethane as defined in claim 2, in admixture with a fuel oil or a solvent miscible with fuel oil.

14. Any new and novel feature hereinbefore described or any new and novel combination of hereinbefore described features.