8/13/2019 Regulation of Properties of Oxidized Asphalt From Heavy Crude

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REGULATION OF PROPERTIES OF OXIDIZED ASPHALT FRO M HEAVY CRU DEE. E. Yudi na, V. Ya. Bam,and A. S. Anto shki n

UDC 665.637.88:541.182

The exhaustion of petroleum reserves has given impetus to the search for new sources ofhydrocarbon raw materials. One such source is heavy crudes, which contain large amounts ofhigh-molecular-w eight hydrocarbons and other compounds. Mini mum processing of these crudeswill yield finished products -- paving asphalts [I ]. This establishes a foundation for orga-nizing production of hlgh-qua lity mat erials of constructi on withou t major expenditures, closeto the raw material productio n site, where shortages have b een felt up to now.

Here we are reporting on a study of the liquid-phase oxidation of heavy crudes and thefeatures of regulatio n of commer cial properties of the final produ cts -- asphalt. As the star t-ing materia l we used a crude from the Karazhanbas field with the following physicochem icalcharacteristics: density at 20~ 941 kg/m3; viscosi ty at 50~ 0.14 Pa.sec; solid point +22~yield of cuts below 350~ 15.6% by weight; co ntent of paraffi nic hydrocarbons 2% by weight,resins 21% by weight, asphalte nes 6% by weight. It will be noted that this crude has a highviscosity and high density and contains very little light products in comparison with conven-tional etudes.

The commercial properties of the asphalts obt ained by oxida tion were regulated by addingasphalt-resin and wax deposits (AKWD) to the crude. These deposits accumulat e on the surfaceof oil-well tubing and discharge lines; they are waste material s in petroleum production andare disposed of by dumping. The ARWD used in the present wor k had the following physicochem-ical characteristics: density at 20~ 989 kg/m s, dropping point 85~ content of asphaltenes2.5% by weight, solid contaminants~.< 1 1.2% by weight.

The liquid-phase oxidation was perform ed in a laboratory unit by a conventional method[2] under the following conditions: total charge 130 g, oxidation time 30 min, temperature270~ air input 1 liter/min. The influence of the usual factors affecting asphalt qualitywas no different from that established in [3] ~ Specific values were selected for the oxida-tion parameters on the basis of the significance of changes in quality index of the finalproduct.

The present work has bee n aimed at control of the physlc ochemic al properties of oxidizedasphalt by varying the dimensions of the complex structural units (CSUs) of this petroleumdisper se syste m (PDS), on the basis of the theory of regu lat ed pha se tra nsitions [4, 5]; afurther aim was to establish the conditions of oxidation unde r which the dimensions of theCSUs of the petroleum system will be optimal.

In Fig. 1 we show the effects of varyin g the crude oil/ARWD ratio in the mixture on cer-tain physicochemical properties of the starting materi al and the final asphalt. In view ofthe nonmonotonic character of the dependence of the R&B softe ning point of the oxidation feed(which expresses indirectly a measur e of inter molecular interaction) on the content of AKWDin the feed, we can assume tentatively that there will be an analogous change in the proper-ties of the processed products. And i n fact, after ox idat ion of the blends of crude wit h ARWD,we found a complex effect of the ARWD on the asphalt quality. As was expected, with ARW Dco n-tents of 30-50% by weight, the change in asphalt propertie s was nonmonotonic (see Fig. i).

The ARWD is a complex mixture of hlgh-molecula r-weight paraffinic--naphthenic and aro-matic hydrocarbons, resins, and asphaltenes. This mae=rial has a rather high structural--me-chanical strength as a consequence of significant int~rm olecular interaction, expressed as arelatively high dropping point. Consequently, an increase in the content of these depositsin the oxidation feed should increase the strength properties of both the original PDS andthe asphalt.

Institute of Chemistry of Petrole um and Natural Salts, Academy of Sciences of the KazakhSSR (Mangyshlak Laboratory). Translated from Khlmiya i Tekhnolog iya Topliv i Masel, No. 7,pp. 10-11, July, 1987.

316 0 0 0 9 3 0 9 2 / 8 7 / 0 7 0 8 0 3 1 6 5 1 2 . 5 0 9 1988 Plenum Publishing Corporation

8/13/2019 Regulation of Properties of Oxidized Asphalt From Heavy Crude

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Fig. 1 Fig. 2F i g . i . S o f t e n i n g p o i n t ( d a s h e d c u r v e ) o f o x i d a -t i o n f e e d a n d n e e d l e p e n e t r a t i o n ( c o n t i n u o u s c u r v e )o f a s p h a l t p r o d u c t a s f u n c t i o n s o f c o n t e n t o f A R W Din feed.F i g . 2 . I n f l u e n c e o f A R W D c o n t e n t i n f e e d o n in -c r e a s e a n d s o f t e n i n g p o i n t o f a s p h a l t i n c o m p a r i -s o n w i t h s o f t e n i n g p o i n t o f f e e d ( c o n t i n u o u s c u r v e )a n d o n r a d i u s of p a r t i c l e s i n a s p h a l t . D i s p e r s i t yo f a s p h a l t s w a s d e t e r m i n e d b y p r o c e d u r e g i v e n i n[ 7 ] , i n a 1 s o l u t i o n o f h e p t a n e - t o l u e n e s o l v e n t( 3 : 1 b y v o l u m e ) .

H o w e v e r , t h e d e c r e a s e i n s o f t e n i n g p o i n t o f t h e f e e d a n d t he s i m u l t a n e o u s i n c r e a s e i np e n e t r a t i o n o f t h e a s p h a l t w i t h c o n t e n t s o f A R W D i n t h e f e e d a m o u n t i n g t o 3 0- 5 0 b y w e i g h t i se v i d e n c e o f t h e r e v e r s e . T h i s i s r e a d i l y e x p l a i n e d o n t h e a s s u m p t i o n o f a n e x t r e m a l c h a n g ei n t he d i m e n s i o n s o f t h e C S U a t t h e s e c o n t e n t s o f A R WD , o w i n g t o a d e c r e a s e i n t h e r a t i o o fs p e c i f i c v o l u m e e n e r g i e s o f t h e d i s p e r s i o n m e d i u m a n d d i s p e r s e p h a s e [ 6] w h e n t h e r a t i o o f P D Sc o m p o n e n t s i s c h a n g e d .

T h e r e l a t i o n s h i p s s h o w n i n F i g . 2 s u p p o r t t h i s h y p o t h e s i s . T h e s y s t e m w i t h 4 0 A R W D i st h e m o s t s u s c e p t i b l e t o t h e a c t i o n o f e x t e r n a l f a c t o r s i n o x i d a t i o n , a n d t h e a s p h a l t p r e p a r e df r o m th i s m a t e r i a l c o n t a i n s C S U s w i t h a m i n i m u m s i z e . C o n s e q u e n t l y , o n e o f th e c o n d i t i o n sf o r a n o p t i m u m i n t h e l i q u i d - p h a s e o x i d a t i o n o f h e a v y c r u d e f r o m t h e K a r a z h a n b a s f i e l d i s ac o n t e n t o f a b o u t 4 0 A R W D b y w e i g h t .

T h u s, i n t he l i q u i d - p h a s e o x i d a t i o n o f h e a v y K a r a z h a n b a s c r u d e , i t is p o s s i b l e t o c o n -t r o l th e a s p h a l t p r o p e r t i e s b y c h a n g i n g t h e C S U d i m e n s i o n s i n o r d e r t o o b t a i n t h e r e q u i r e ds t r u c t u r a l - m e c h a n i c a l p r o p e r t i e s . O n e m e t h o d f p r a c c o m p l i s h i n g s u c h c o n t r o l i s t h e i n t r o d u c -t i o n o f A R W D i n t o t h e f e ed . T h i s a p p r o a c h m a k e s i t p o s s i b l e n o t o n l y t o o b t a i n v a l u a b l e m a -t e r i a l s o f c o n s t r u c t i o n , b u t a l s o to s o l v e s u c c e s s f u l l y c e r t a i n e c o l o g i c a l p r o b l e m s i n p e t r o -l e u m p r o d u c t i o n a n d p r o c e s s in g .

L I T E R A T U R E C I T E Di . N . K . N a d i r o v , A . E . B r a u n , M . S . T r o k h i m e n k o , e t a l . , P e t r o l e u m B i t u m i n o u s R o c k s o f

K a z a k h s t a n : P r o b l e m s an d P r o s p e c t s [ i n R u s s i a n ] , N a u k a , A l m a - A t a ( 1 9 8 5) .2 . R . B . G u n , P e t r o l e u m A s p h a l t s [ i n R u s s i a n ] , K h i m i y a , M o s c o w ( 1 9 73 ) .3 . I . B . G r u d n i k o v , P r o d u c t i o n o f P e t r o l e u m A s p h a l t s [ i n R u s s i a n ] , K h i m i y a , M o s c o w ( 1 98 3 ).4 . Z . I . S y u n y a e v , K h i m . T e k h n o l . T o p l . M a s e l , N o . 6 , 2 - 5 ( 1 9 8 5 ) .5 . Z . I . S y u n y a e v , K h i m . T e k h n o l . T o p l . M a s e l , N o . 8 , 5 - 7 ( 1 9 8 6 ) .6 . R . Z . S y u n y a e v a n d O . G . S a f i e v , I z v . V y s s h . U c h e b n . Z a v e d . , N e f f ' G a z , N o . 2 , 5 0 - 5 4 ( 19 8 4 ) .7 . I . Y a . S l o n i m , O p t . S p e k t r o s k . , ~ , N o . i , 9 8 - 1 0 8 ( 1 9 6 0 ) .

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