Abstract: A panel connected body includes a plurality of flat panels arranged in a matrix of m rows and n columns, where m?3 and n?3; and a plurality of row-direction connection portions and column-direction connection portions which connect together panels that are adjacent in a row direction and column direction, respectively. A first type row satisfying relationships D1?2L and Dy?Dy?1?2L and a second type row satisfying relationships Dn?2L and Dy?Dy+1+2L are alternately included, where Dy is a length along the column direction of the column-direction connection portions in a y-th column, and L is a thickness of the panels. The relationship E?WC?L is satisfied, where WC is a length along the column direction of the panels and E is a length along the column direction of the row-direction connection portions.

Abstract: A petroleum pitch or coke of a high purity is produced from a petroleum heavy residue such as distillation and cracked residua, asphalt and pitch by such treatment of the residue prior to a conventional pitching or coking treatment that the residue is treated with hydrogen in the absence of a catalyst under a hydrogen pressure of 20.about.200 Kg/cm.sup.2 under a gradual heating up to a final temperature of 350.degree..about.400.degree. C. so as to heat the residue from 150.degree. C. to 300.degree. C. over 30 to 120 minutes and then from 300.degree. C. to the final temperature over 10 to 60 minutes. The non-catalytic hydrogen treatment is called "hydrogenation refining step", which gives a refined pitching/coking feedstock from which a petroleum pitch or coke of extra high purity is derived.

Abstract: In the production of high-density carbon materials directly from a green coke without the aid of a binder by a process comprising molding a finely pulverized green coke as such by pressing in a mold, demolding and baking the molded green coke to form a sintered carbon material and, if desired, graphitizing the sintered material, a serious disadvantage that there occur laminar cracks in the molded green coke at the demolding stage is avoided by molding the green coke in the form of a composition comprising a finely pulverized green coke in intimate admixture with a small amount of water or a certain monohydric alcohol.

Abstract: A high crystalline coke can be prepared by heat-soaking a petroleum feedstock in the presence of added dissolved sulfur, heating to effect controlled thermal cracking thereof, separating non-crystalline substances as pitch, recovering a heavy cokable residue from the pitch free feed, and subjecting the residue to delayed coking.

Abstract: A high-crystalline petroleum coke is produced from low-sulfur petroleum feedstock such as virgin crude oil, distillation residuum and cracked residium by subjecting the feedstock to preheat treatment under specific conditions to effect cracking and soaking thereof, subjecting the preheat-treated feedstock to flash distillation to remove non-crystalline substances contained therein as pitch and to recover distillate, fractionating the distillate to provide a heavy residue and subjecting the heavy residue to a delayed coking under specific conditions to produce the desired coke which has a coefficient of thermal expansion of less than 1.0 .times. 10.sup.-6 /.degree. C over 100.degree.-400.degree. C.

Abstract: A petroleum coke of unusually high-crystalline texture and of high purity is produced from a low-sulfur petroleum material by a process including a preheat-treating step for removing non-crystalline substances contained in the material as pitch or coke and a coking step wherein a heavy oil derived from the preceding step is coked in a coking crystallizer in such a manner that pitch-like heavy oil downwardly flows and is progressively accumulated and coked therein while gaseous light hydrocarbons are discharged at the upper part of crystallizer whereby the coking is conducted with a high growth and high orientation of coke crystals formed.

Abstract: Any kind of virgin, low-sulfur crude oil is directly treated in a two-stage delayed coking process for yielding non-crystalline coke in the first stage and high-crystalline coke in the second stage, which process comprises preheating the crude oil in a tube heater to 460.degree. - 520.degree.C under 5-20 kg/cm.sup.2 G, maintaining the oil therein at that temperature for 30 - 500 seconds to allow the oil to be heat-soaked, subjecting the oil to first delayed coking under relatively mild conditions and subjecting the uncoked heavy residual oil to second delayed coking under relatively severe conditions.