US1933748A - Process for treating hydrocarbon oils - Google Patents

Description

Patented Nov. 7, 1933 UNITED ser es "EP Jacque-C. Morrell, Chicago, 111., assignortoUniversal Oil Products Company, Chicago, 111., a corporation of South Dakota I No Drawing. Application November 15, 1929" Serial No. 407,373 I 1 Claim. ((31. 196Z9) This invention relates to the treatment of It is the purpose of the present invention to'cut hydrocarbon oils such as petroleum distillates down materially the amountoi sulphuric acid and more particularly to crackedhydrocarbon required for desulphurization by treating sepa oils. I n rately with reagents which remove or assist. in

5 In the ordinary refining oisuch petroleum di"- removing the sulphur compounds without accom- 60 tillates various modificationsof sulphuric acid panying serious losses due to acid treatment. treatment are usually employed, consisting of 'ihepresent invention is directed particularly to treating with sulphuric acid, caustic soda, and the use of the acids'and the oxides of nitrogen plumbite solution in separate steps and in vary and complex compounds or" the latter, specifically ing order. While the ordinary sulphuric acid m ne and nitrous acid, nitrous oxide, nitric ox'- 65 treatment and other treatments, such as with nitrogen dioxide, nitrogen trioxide, nitroe clays, suffice for some kinds oi cracked distillates, gen tetroxide and nitrogen pentoxide in there=- they are not satisfactory for the treatment of fining oi cracked distillates. At elevated temdistillates containing high ercentages or" sulperature, for example between 159 and 359 F.,

phur compounds. Sulphuric acid is a suitable more or less, the oxides are preferably diluted 70 reagent for removing ordinary sulphur comwith inert gases such as carbon dioxide, nitrogen, pounds from petroleum distillates, but the comflue gas containing little or no oir, etc. The reaposition of cracked distillates is such that enorson for this is the very explosive nature of the mous losses are entailed when it is attempted to oxides of nitrogen and hydrogen vapors. In

both refine with respect to color,- odor and treating the distillates with the acids, they may 75 stability, and also with respect to removal of be simply refluxed and given a subsequent treatsulphur compounds by treatment with sulphuric ment which will be hereinafter described. In acid. treating the distillates with the oxides of nitro- The removal of sulphur compounds is included gen, all of which are gases, the temperature is in refining but is handled separately here bevery carefully regulated while the gases are bub- 80 cause for the ordinary treatment of cracked disbled through the body of oil in one modification tillate to produce a product of satisfactory color of the process. Low temperatures, i. e. considand odor, a relatively small amount of sulphuric erably below atmospheric e. g. 10-20" F. are deacid is'required, while to remove a substantial sirable in someicases. In order to prevent too percentage of sulphur compounds in addition a great a loss of oil vapors, the oil container should. s5

' very large quantity of sulphuric acid is required. be connected with a reflux condenser ii the tem- Cracked distillates are composed of several perature is in any way elevated. The unused primary groups of. hydrocarbons which include gases may be recirculated back through the liqthe important unsaturated and aromatic hydrouid body by means of a suitable pump or comcarbons, both of which react with sulphuric acid, pressor. As an alternative method of treatment in particular the unsaturated hydrocarbons. The the distillate may be vaporized and the highly aromatic and unsaturated hydrocarbons are pardiluted oxide of nitrogen passed directly into the ticularly important in motor fuels because of vapor zone. their anti-knock properties permitting the oper- Preferably the container is so arranged that 40 ation Of motors Bib greater efficiency. either i the gases have to be passed through the longest ordinary operation or in the operation of high path of tr el, for exam le, i a Vertical Compression p In Ordinary fi g. only tamer, or through suitably arranged baffles in a sufficient amount of acid is used to remove the horizontal container. As the temperature of highly unsaturated hyd arbo s Such a th treatment should not be excessive, the oil may be diolefines, but with a large amount of sulphuric heated when desired means of heating coils 100..

a Which is required deslllphullzing. placed within the oil body an alternative to higher percentage Of the d d unsaturated yexternal heating, or the oil may be circulated drocarbons, and a S sta percentage oi the through a coil obtaining heat from any source. aromatic hyd a a v d along wit When treating with the acids directly, proper 50.1 p Compounds- In additi n 6 this removal precautions, well known in the art, should be and direct loss of material, low boiling unsatud prevent corrosion rated hydrocarbons with the gasoline ra e a The oil which has been treated as described for Convert d into higher boiling y rbons in from one to several hours, more or less,is then the gas oil range by acid treatment owing to a subjected to further treatment with caustic solu- 551 reaction known as polymerization. tions after which the caustic is withdrawn. 0

While this caustic treating step is not absolutely necessary, it is desirable, as it facilitates subsequent operations. The oil is then treated with sulphuric acid using from 10 to 30 pounds, more or less, per barrel of distillate. The acid is preferably concentrated, for example, from 90 percent up to the concentrations of fuming acid, for example, so-called 130 percent. The acid treatment is applied in the usual manner by proper mixing and contacting with the oil and the sludge from the treatment withdrawn. The oil may then be water washed or treated with the caustic solutions. The caustic is removed and the oil distilled in the presence of steam. The treatment with the acids or oxides of nitrogen or derivatives thereof, is the principal step in the process although the benefits of the invention depend, in a large measure, on the combination of such treatment with the subsequent treatments described. The said sulphur removal compared with ordinary sulphur treatment is increased and the losses by reaction, solution and polymerization are greatly decreased by the application of this process.

My invention, therefore, results in the production of superior products, entailing much smaller losses of the distillates undergoing treatment when compared with ordinary sulphuric acid treatment, and especially saving those hydrocarbon groups in the distillate which are desirable for motor fuel uses, particularly for anti-knock purposes. In one method of applying the process and as an alternative, the oxides of nitrogen may be combined to form relatively loose or unstable compounds with other substances, for example, nitrogen dioxide with sulphuric acid to form the well known nitrosyl sulphuric acid and also with ferrous sulphate to form a brownish complex compound. The latter may also be made by treating nitric acid direct with ferrous sulphate. In applying the latter reagents various combinations and temperatures are used.

As an example a pressure distillate of 54 B. gravity and a sulfur content of 0.8% produced a gasoline with an initial boiling point of 102 F. and end point of 437 F. and sulphur content of 0.12% when treated as described by a mixture of oxides of nitrogen followed by treatment with sulphuric acid and caustic in the steps described. The sulphur content of the finished product by ordinary treatment was 0.2%. The gasoline possessed good color, odor and stability.

A process for desulphurizing hydrocarbon oils containing unsaturated hydrocarbons and sulphur which comprises treating such oil at elevated temperature with a gaseous oxide of nitrogen diluted with inert gas and then subjecting the thus treated oil to the action of sulphuric acid.

JACQUE C. MORRELL.