Mineral oils: processes and products – Asphalts – tars – pitches and resins; making – treating and... – Chemical modification of asphalt – tar – pitch or resin
Patent
1984-04-17
1987-02-03
Metz, Andrew H.
Mineral oils: processes and products
Asphalts, tars, pitches and resins; making, treating and...
Chemical modification of asphalt, tar, pitch or resin
208 42, 208 45, 208309, 208 39, C10C 120, C10C 302
Patent
active
046407618
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a process for preparing pitch and more particularly to a process for preparing pitch containing little or substantially no quinoline insoluble components (hereinafter referred to as "QI components").
BACKGROUND ART
In producing high-quality carbon materials such as needle coke, carbon fiber or the like from coal tar, QI components contained as impurities in the coal tar must be removed to utmost extent. The QI components in coal tar are carbonaceous materials in the form of fine particle 0.3 .mu.m or less in particle size (such QI components are generally called "primary QI components"). When coal tar contains a large amount of primary QI components, the primary QI components tend to adhere to the surface of mesophase bodies (spherulites generally called "secondary QI components") during the heat treatment of the coal tar. The adhesion of primary QI components is presumed to inhibit the aggregation of the spherulites and to hinder their normal growth.
For this reason, the removal of primary QI components from coal tar has been recognized as important. For example, a method has been practiced in which oil of such property that the oil and coal tar are hardly miscible each other, e.g. petroleum-type light oil, is added to coal tar to aggregate the primary QI components of the coal tar into particles of increased particle size and the mixture is left to stand to separate the enlarged solids by sedimentation (Japanese Unexamined Patent Publication No. 28501/1977). This method requires the distillation of the supernatant liquid after removing the primary QI components in order to get tar and/or pitch as useful component and must recover the oil initially added by distillation. The distillation of the liquid requires a great amount of thermal energy and also results in low yields of the useful component. Further, the oil recovered by the distillation is a mixture of the petroleum-type oil added and coal-type oil derived from coal tar and thus has a limited value in use unless further treated. Since the precipitate phase separated by standing contains a large amount of petroleum-type oil, the oil as added would be recovered at a low ratio if the precipitate is not subjected to a treatment for the recovery of oil. And the recovery treatment requires equipments such as a distillation column, tanks, etc. Moreover, this method involves the use of a large-size tank for storing petroleum-type light or middle oil to be used and related installations, consequently demanding a wide space for arrangement of the equipments.
DISCLOSURE OF INVENTION
We have conducted extensive research to solve or moderate the foregoing problems encountered in carrying out the conventional methods and found the following.
(i) When coal tar or coal tar pitch is heat-treated before centrifugation at high temperatures, the primary QI components are aggregated into solids of increased apparent particle size so that a remarkable centrifugal efficiency is achieved and the primary QI components are efficiently separated with extreme ease.
(ii) When carbonaceous particles are added to coal tar or coal tar pitch before the heat treatment in the procedure as described above in (i), the secondary QI components produced by the heat treatment act as a kind of binder to stick the primary QI components to the surfaces of carbonaceous particles. As a result, the primary QI components which have swollen the carbonaceous particles are easily and efficiently separated together with the carbonaceous particles by centrifuging at a high temperature the reaction product from the heat treatment.
(iii) When coal tar-type light or middle oil is added to the reaction product resulting from the heat treatment of coal tar or coal tar pitch in the procedure stated above in (i) or (ii) before high-temperature centrifugation, the reaction product is rendered less viscous and the high-temperature centrifugal efficiency is further improved.
The present invention has been accomplished based on these novel findings.
In the proces
REFERENCES:
patent: 659076 (1900-10-01), Lennard
patent: 1844896 (1932-02-01), Miller
patent: 2449404 (1948-09-01), Miller
patent: 2631982 (1953-03-01), Donegan
patent: 3010893 (1961-11-01), Kulik
patent: 3970524 (1976-07-01), Borgertman
patent: 3992281 (1976-11-01), Benade
patent: 4259171 (1981-03-01), Stadelhofer et al.
patent: 4264453 (1981-04-01), Mravick
patent: 4405439 (1983-09-01), Simone
patent: 4436615 (1984-03-01), Boodman et al.
patent: 4462824 (1983-09-01), Sunami et al.
patent: 4482452 (1984-11-01), Shigeta et al.
Kibe Satoshi
Maeda Toyohiro
Mori Makihiko
Metz Andrew H.
Myers Helane
Osaka Gas Company Limited
LandOfFree
Process for preparing pitch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing pitch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing pitch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1090522