A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement: SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

A sintered refractory product having the form of a block and consisting of a granulate formed by all the grains having a size larger than 100 m, referred to as coarse grains, and a matrix binding the coarse grains and consisting of the grains having a size smaller than or equal to 100 m, the granulate representing between 45% and 90% by mass of the product, the product having a composition such that, in a mass percentage based on the oxides: Al.sub.2O.sub.3>80%, SiO.sub.2<15%, Na.sub.2O<0.15%, Fe.sub.2O.sub.3<0.05%, CaO<0.1%, the other oxides forming the remainder up to 100%, and the Na.sub.2O content in the matrix being greater than 0.010%, in a mass percentage based on the mass of the product.

Apparatus and methods are provided for converting methane in a feed stream to acetylene. A hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process.

A reactor system for high temperature reactions of reactants includes at least one reactant containing carbon. The reactor includes a reactor, a liquid media disposed within the reactor, and a solid carbon reaction product. The liquid media does not react irreversibly with the reactant to form products, and the liquid media wets at least a portion of a surface within the reactor. The solid carbon reaction product does not contact at least the portion of the surface within the reactor where the liquid media wets the portion of the surface within the reactor.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement: SF:NP in the cementitious blend composition lies in the range of (24-63): (5-44): (32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A method for cracking hydrocarbon, comprises: providing steam and hydrocarbon; and feeding steam and hydrocarbon into a reactor accessible to hydrocarbon and comprising a perovskite material of formula A.sub.aB.sub.bC.sub.cD.sub.dO.sub.3, wherein 0<a<1.2, 0b1.2, 0.9<a+b1.2, 0<c<1.2, 0d1.2, 0.9<c+d1.2, 0.5<<0.5; A is selected from calcium, strontium, barium, and any combination thereof; B is selected from lithium, sodium, potassium, rubidium and any combination thereof; C is selected from cerium, zirconium, antimony, praseodymium, titanium, chromium, manganese, ferrum, cobalt, nickel, gallium, tin, terbium and any combination thereof; and D is selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, titanium, vanadium, chromium, manganese, ferrum, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, gallium, indium, tin, antimony and any combination thereof.

The invention relates to an orifice chamber designed to expand a gas, in particular intended for a fluid catalytic cracking unit, said orifice chamber comprising the following elements: a chamber having an axis (X), an inlet duct that opens into the chamber, an outlet duct located on the opposite side from the inlet duct following said axis (X), and a plurality of internal plates positioned crosswise to the axis (X) inside the chamber at a distance from one another along the axis (X), each internal plate being provided with a plurality of through-orifices, characterized in that at least the plurality of internal plates is made of a ceramic material.