US2125875A - Diesel fuel - Google Patents

Description

Patented Aug. 9, 1938 DIESEL FUEL Daniel I. Barnard, IV, Hammond, Ind., assignor to Standard Oil Company, Chicago, Ill, a corporation of Indiana.

No Drawing. Application April 17, 1935, Serial No. 16,828

9 Claims.

This invention relates to improved fuels for- Diesel engines and particularly to improved fuels for Diesel engines of the high speed type.

The so-called low speed Diesel engines customarily used in stationary power plant instal1a-.

tions are adapted to the use of a wide variety of fuels. This. however, is not true of the newer high speed types of Diesel engine suitable for automobile, airplane and rail car use. By the expression high speed types" I refer to engines operating at 800 revolutions per minute or over and usually at 1,000 revolutions per minute or over. These types of engine not, only require clean, high grade fuels having physical properties falling within a relatively narrow range but they also require fuels having chemical properties such as to give the proper ignition qualities.

It is an object of my invention to provide Diesel fuels having improved ignition qualities and at the same time having thedesired physical properties. Another object of .my invention is to provide an improved method of operating Diesel engines of the high speed types, by the use of such fuels. Other and more detailed objects of my invention will become apparentas the description thereof proceeds.

The ignition qualities of Dieselfuels are usually defined by their cetene numbers". This is discussed by Boerlage and Broeze in the S. A. E. Journal, vol. 31, page 283 et seq. (1932) and elsewhere. Cetene ignites very readily. in typical high speed Diesel engines. Mesitylene, on the .other hand, will not ignite at all. The cetene number of a given fuel is determined by finding a blend of cetene and mesitylene having the same ignition qualities as determined, for instance, by measurement of ignition delays expressed in crankshaft degrees. The cetene number of a given fuel is the number of parts of cetene in 100 parts of the cetene-mesitylene blend having equal ignition qualities. Thehigher the cetene number the better the ignition qualities.

Diesel fuels made from certain types of oils have, in general, higher cetene numbers than corresponding fuels made from other types of oils. Thus a gas oil made by the non-cracking distillation of Mid-Continent crude was found to have a cetene number of 57, a corresponding gas oil made from. a Winkler County, Texas gas oil was found to have a cetene number of 48 and a corresponding product madefrom cracking stlllresidues was found to have a cetene number of 38.

I have found that the cetene numbers of Diesel fuels can be improved by incorporating paraffin wax in such fuels. Thus by adding 2.5% of a 120-125 F. melting point paraflln wax to the above Winkler gas oil the cetene number was raised from 48 to 51. 5% of this same wax raised the cetene number to 53. This diilerence is relaunsuitable for that purpose.

(El. M-ii) tively small numerically but has a large effect on the ignition'qualities of the fuel.

The addition of paraflin wax has, however, a compensating disadvantage in that the pour point of the fuel is raised. This interferes 5 .seriously with low temperature operation by causing clogging ofthe fuel lines, etc. For this reason oils containing paraffin wax have in the past been avoided for Diesel fuel use and my invention thus runs directly contra to the teachings of the prior art.

I have found that the disadvantage incident to the addition of paraflin wax can be overcome by the incorporation of a material which not only tends to lower the pour point but also tends to 15 raise the cetene number still further. Materials of this type include resins produced from the condensation of high molecular weight paraflin hydrocarbons, dehydrogenated paraffin hydrocarbons or halogenated parafin hydrocarbons 20 with aromatic hydrocarbons or their derivatives, particularly polynuclear aromatic hydrocarbons such as naphthalene, anthracene, diphenyl, etc. Condensation products of chlorinated paraflin wax with naphthalene are particularly suitable. 5 Resins of this type may be made in accordance with the teachings of MacLaren Patents 1,963,917 and 1,963,918. I

Thus, for example, the addition of one percent of a resin produced by the condensation of a 30 chlorinated paraflln wax with naphthalene in accordance with MacLaren Patent 1,963,917 to the aforementioned Winkler gas oil containing added parafiln wax reduced the pour point to that of the original gas oil, namely -35 F. At the same 35 time the cetene number was raised due tothe high cetene number of the resin.

While other pour point depressors can be used I prefer to use pour point depressors of the aforementioned types or other pour point depressors of high cetene number. Hydrocarbon pour point depressors are particularly suitable.

It is desirable to choose an oilof high cetene number and add wax or wax and resin to it in accordance with my invention, but by the addition of wax or wax andresin it is possible to start with an oil of low cetene number, e. g. a cracked 011. By means of my invention it is thus possible to produce a satisfactory fuel for high speed 0 Diesel engines from an oil heretofore considered The maximum amount of wax to be added is determined byits solubility in the oil. In general, amounts from one percent up to five percent or ten percent are suitable. I prefer to use a low melting point wax since such waxes are more sol uble in oil and at the same time are of lower economic value for other purposes as compared with the waxes of higher melting point. when using a low melting point wax as much as can sometimes be added.

A paraflln wax having a melting point of 100 F. to 120 F. is highly suitable. Other waxes melting from 80 F. up to 140 F. or even higher can be used. While I prefer to use paraffin wax, other petroleum waxes, notably the petrolatum waxes, can also be used.

The amount of resinous material or other pour point depressor can also be varied within considerable limits. As little as 0.1% is effective in some cases and as much as 10%, 20% or even more can often be used. The amount used should be suflicient to lower the pour point to the desired figure which will depend on the atmospheric conditions to be encountered in the use of the fuel.

The pour point should usually be lowered to a.

figure under 30 F. and preferably under 15 F.

Diesel fuels in accordance with my invention should meet the following specifications:

10% distillation point-not over 460 F. and preferably not over 400 F.

90% distillation point-not over 675 F. and preferably not over 450 F.

End distillation point-not over 720 F. and preferably not over 500 F.

Water and sediment-not over 0.5% and preferably not over 0.1%

Cetene number not under 45 and preferably not under 50 While I have described my invention in connection with certain specific embodiments thereof it is to be understood that these are merely by way of illustration. The appended claims define the novel features of my invention.

I claim:

l. A method of raising the cetene number of a high speed Diesel engine fuel oil having a 10% distillation point of between 400 F. and 460 F., a 90% distillation point of between 460 F. and 475 F. and an end distillation point of between 500 F. and 720 F. which comprises adding and dissolving in said fuel oil from about to about 20% of paraiiin wax and from about 1% to about 20% of a pour point depressor of the condensation type obtained by reacting a halogenated hydrocarbon and an aromatic hydrocarbon, said pour point depressor being used in an amount sufficient to lower the pour point of the fuel to below 30 F. and to increase further the cetene number thereof.

2. A method in accordance with claim 1 in which said pour point depressor is a condensation product of chlorinated paraflin wax and naphthalene.

3. A fuel for high speed Diesel engines comprising a hydrocarbon oil having a distillation point of not over about 460 F., a 90% distillation point not over about 675 F. and an end distillation point not over about 720 F.-, containing from about 5% to about 20% of paraflin wax and from about 0.2% to about 20% of a resinous high cetene number pour point depressor of the condensation type obtained by reacting a halogenated hydrocarbon and an aromatic hydrocarbon, said paraflin wax having a melting poin of from about 100 F. to about 120 F.

4. A fuel for high speed'Diesel engines comprising a hydrocarbon oil having a 10% distillation point not over about 460 F., a 90% distillation point not over about 675 F., and an end distillation point not over about 720 F., containing from about 5% to about 20% of added paraflin wax and a pour point depressor of the condensation type obtained by reacting a halogenated hydrocarbon with an aromatic hydrocarbon, said pour point depressor being used in quantities sufficient to lower the pour point of the fuel to below 30 F. and to further increase the cetene number thereof.

5. A fuel according to claim 4 in which said paraffin wax has a melting point between about 80 F. and about 140 F.

6. A fuel according to claim 4 in which the pour point depressor is a condensation product of chlorinated parafiln wax and naphthalene.

7. A fuel for high speed Diesel engines having a cetene number of at least 50 comprising a hydrocarbon oil having a 10% distillation point not over about 460 F., a 90% distillation point not over about 675 F., and end distillation point not over about 720 F. and an initial cetene number under 50, containing from about 5% to about 20% of dissolved paraflin wax and a condensation product obtained by reacting halogenated hydrocarbons with a polynuclear aromatic hydrocarbon, said condensation product being used in an amount sufficient to lower the pour point of the fuel to below 30 F. and .to further increase the cetene number thereof.

8. A fuel for high speed Diesel engines comprising a cracked hydrocarbon oil of low cetene number unsuitable for use as a fuel for high speed Diesel engines, from about 5% to about 20% of paraflin wax added to and dissolved in said cracked hydrocarbon oil to substantially raise the cetene number of said cracked hydrocarbon oil to render it suitable for use as a fuel for high speed Diesel engines, and from about 0.2% to about 20% of a p'our point depressor of the condensation type obtained by reacting a halogenated hydrocarbon and an aromatic hydrocarbon adapted to lower the pour point of said cracked hydrocarbon oil containing said added paraflln wax to a figure under 30 F. and to increase further the cetene number of said cracked hydrocarbon oil, said cracked hydrocarbon oil having a 10% distillation point of between 400 and 460 F., a 90% distillation point of between 450 F. and 675 F. and an end distillation point of between 500 F. and 720 F.

9. A fuel for high speed Diesel engines comprising a cracked hydrocarbon oil of low cetene number unsuitable for use as a fuel for high speed Diesel engines, from about 5% to about 20% of paraflln wax added to and dissolved in said cracked hydrocarbon oil to substantially raise the cetene number of said cracked hydrocarbon oil to render it suitable for use as a fuel for high speed Diesel engines, said paraflln wax having a melting point of from about 100 F. to about 120 F., and from about 0.2% to about 20% of a resinous high cetene number pour point depressor of the condensation type obtained by reacting a halogenated hydrocarbon and an aromatic hydrocarbon adapted to lower the pour point of said cracked hydrocarbon oil containing said added paraffin wax to a figure under 30 F., and to increase further the cetene number of said cracked hydrocarbon oil, said cracked hydrocarbon oil having a 10% distillation point of between 400 F. and 460 F., a 90% distillation point of between 450 F. and 675 F., and an end distillation point of between 500 F. and 720 F.

DANIEL P. BARNARD, IV.