Process for nitrogen removal from hydrocarbonaceous materials

Hydrocarbonaceous material is contacted with particulate coal to cause said coal to sorb a substantial portion of the basic nitrogen compounds contained in said hydrocarbonaceous material.

The present invention is directed to a method of improving the quality of 
hydrocarbonaceous material by removing basic nitrogen heteroatoms. More 
particularly, the invention relates to a process comprising contact of a 
hydrocarbonaceous material with coal for the purpose of basic nitrogen 
heteroatom removal. 
In U.S. Pat. Nos. 4,261,813, 4,271,009, 4,272,361 and 4,827,051 there are 
disclosed methods of removing nitrogen-containing compounds from 
hydrocarbonaceous liquids by contacting said liquids with an acid solvent. 
In U.S. Pat. No. 4,268,378 there is disclosed a method for reducing the 
nitrogen content of shale oil by mild hydrogenation followed by liquid 
sulfur dioxide extraction. These methods of removing nitrogen from 
hydrocarbonaceous liquids involve not only specialized procedures, but 
also require special equipment, particularly for transferring the highly 
corrosive acid solvent. 
The present invention is based in part on the discovery that basic nitrogen 
heteroatoms may be sorbed from hydrocarbonaceous material, particularly 
from coal-derived liquid, by contact with coal. The removal of such 
compounds improves the quality of the hydrocarbonaceous liquid in at least 
three ways. Firstly, if the liquid product is to be utilized for 
combustion, NO.sub.x emissions are minimized. Secondly, if the liquid 
product is to be upgraded further, hydrogen consumption will be minimized 
in that it no longer be required for nitrogen removal. Also, some nitrogen 
compounds are strongly absorbed on catalysts and therefore deactivate 
(poison) the catalyst. Basic nitrogen heterocyclic compounds are 
particularly undesirable for this reason. Other nitrogen-containing 
compounds, such as, ammonia and aliphatic amines are less deleterious on 
catalysts. Thirdly, in addition to catalyst poisoning and interfering with 
catalytic conversion, nitrogen-containing compounds can further cause 
product-instability in that these compounds which have the undesirable 
effect of increasing the viscosity of the hydrocarbonaceous liquid. Thus, 
the removal of nitrogen compounds reduces the viscosity of the liquid and 
also will prevent viscosity increases during storage. 
It is therefore an object of the present invention to provide a method for 
improving the quality of hydrocarbonaceous materials by removing the basic 
nitrogen compounds therefrom. 
In accordance with the present invention there is provided, a process 
comprising the step of contacting particulate coal with liquid-phase 
hydrocarbonaceous material containing basic nitrogen compounds, at a 
temperature ranging from about ambient to about 600.degree. F. at 
atmospheric pressure for a period sufficient for the coal to substantially 
sorb the basic nitrogen compounds from the hydrocarbonaceous material. 
Subsequent to said treatment the improved hydrocarbonaceous material may 
be separated from the coal. If the hydrocarbonaceous material is used for 
combustion, it will exhibit low NO.sub.x emission due to the substantial 
absence of nitrogen compounds. 
The term "coal" is intended to include all grades of coal such as 
anthracite, bituminous, semi-bituminous, subbituminous coal, lignite, peat 
and mixtures thereof. Application of the present invention, to bituminous, 
semi-bituminous, sub-bituminous coal, and lignite is particularly useful.

The present invention may be applied as a treatment for hydrocarbonaceous 
liquids, such as petroleum or petroleum-derived liquids, oil shale or oil 
shale-derived liquids, coal-derived liquids, byproducts of coke production 
or coal gasification, tar sands or tar sand-derived material. A preferred 
hydrocarbonaceous liquid is full-range coal-derived liquid. The invention 
is applicable to types of products derived from direct coal liquefaction 
processes. One of the types of such products is a coal-derived distillate 
(bp 400.degree.-850.degree. F.) which typically may contain about 70% 
hydrocarbons (hydro- and polyhydroaromatics), 8% heterocyclic compounds 
(mostly ethers), 10% monophenols (predominantly less than 10 carbon atoms) 
and 12% polyphenols and basic nitrogen compounds. Of these classes of 
compounds, about 30-50% of the total liquid may be composed of the 
following compounds: naphthalene, methylnaphthalene, biphenyl, diphenyl 
ether, phenathrene and/or anthracene, and pyrene. A substantial portion of 
the basic nitrogen compounds present may be quinolines. 
Since such coal-derived liquid products may be lightly hydrogenated, the 
basic nitrogens are preferably in the form of partially hydrogenated 
heterocycles, such as, 1,2,3,4-tetrahydroquinolines, indolines, and the 
like. Preferably, the coal-derived liquid products are low in phenolic 
compounds which may inhibit or prevent the basic nitrogen sorption by 
coal. 
The treatment of hydrocarbonaceous material with particulate coal according 
to the present invention will be conducted under relatively mild 
conditions because if the conditions are too severe, the nitrogen 
compounds will be redistributed between the hydrocarbonaceous material and 
the coal. We have therefore found that by subjecting the hydrocarbonaceous 
material to coal from about 1 to 180 minutes, usually less than 60 minutes 
at ambient to 600.degree. F. and substantially atmospheric pressure, the 
basic nitrogen sorption is maximized, thereby providing an improved liquid 
product or hydrocarbonaceous fuel. The preferred sorption conditions are 
300.degree. F. for 60 minutes. 
Referring to the Figure, there is illustrated a sorption tank 10 
accommodated with inlets 11 and 12 for coal and liquid or slurried 
hydrocarbonaceous material, respectively. The hydrocarbonaceous material 
will contain basic nitrogen heteroatoms and may be, for example, 
coal-derived liquid products having a boiling point from 
400.degree.-1000.degree. F. and preferably less than 5% by weight oxygen 
containing compounds. It is particularly preferred that the basic nitrogen 
compounds comprise partially hydrogenated heterocycles, such as 
1,2,3,4-tetrahydroquinoline, indoline and the like. Sorption tank 10 is 
further equipped with motor 13, agitating means 14 and air vent 15. The 
coal and hydrocarbonaceous material mixture 16 may be pumped by pump 17 
and recycled via valve means 18a through heating means 18 such that the 
mixture is maintained within a temperature range of ambient to 600.degree. 
F. The pressure within tank 10 may be atmospheric and the mixture 16 may 
be agitated and heated at the aforementioned preferred temperature for a 
period of approximately 1 hour, after which time heating means 18 is 
bypassed via valve 18a and the mixture is conducted by line 19 into solids 
separation means 20 whereby the coal containing sorbed basic nitrogen 
compounds may be withdrawn via line 21 and conducted to slurry preparation 
means (not shown) for treatment by direct coal liquefaction processes or 
some other purpose. This hydrocarbonaceous material which is substantially 
depleted of basic nitrogen compounds may be withdrawn through line 22. 
The hydrocarbonaceous material treated according to the present invention 
may be further benefitted as previously described by repeating the 
process. Repetitive treatments are particularly desirable when the initial 
nitrogen compound content of the hydrocarbonaceous material is too high to 
be removed by one treatment. 
Hydrocarbonaceous material prepared according to the present invention may 
be used as a combustion fuel since the removal of the basic nitrogen 
compounds minimize NO.sub.x emission and if further upgrading is required, 
the removal of the nitrogen bearing compounds will ultimately reduce 
hydrogen requirements for upgrading and improve the life of the upgrading 
catalyst. 
If desired, the particulate coal may be provided substantially free of 
water prior to the sorption step. Drying of the coal may be accomplished 
by warming the coal in presence of an inert sweep gas prior to mixing with 
the hydrocarbonaceous stream. 
The following example illustrates removal of 1,2,3,4-tetrahydroquinoline 
(THQ) from a hydrocarbonaceous liquid (1-methylnaphthalene) by contact 
with coals from various sources. 
EXAMPLE 
Twenty-five grams of a specific coal were added to fifty grams of 
1-methylnaphthalene containing known concentrations of THQ. This slurry 
was then heated to, mixed and held at 200.degree. F. for 3 hours. After 
cooling and filtration, the filtrate was analyzed for percent THQ content. 
__________________________________________________________________________ 
WT % THQ IN 
METHYL- WT % OF MOIS- 
WT % THQ IN 
NAPHTHALENE TURE IN COAL 
METHYL- 
PRIOR TO BEFORE NAPHTHALENE 
TREATMENT TYPE OF COAL 
TREATMENT FILTRATE 
__________________________________________________________________________ 
1% Indiana V (bituminous) 
5.1% .035% 
1 Kentucky 9 (bituminous) 
2.2 .36 
1 Clovis Point 
23.06 0.15 
(sub-bituminous) 
5 Indiana V 5.1 1.9 
5 Kentucky 9 2.2 2.4 
5 Clovis Point 
23.06 2.2 
__________________________________________________________________________