Abstract: A cascaded energy storage system includes: a gas storage which is divided into at least one air chamber and at least one working medium gas chamber by a flexible diaphragm, where pressure of the air chamber is equal to pressure of the working medium gas chamber, and volume of the air chamber and volume of the working medium gas chamber is capable of being adjusted by contraction and expansion of the flexible diaphragm; an air compression and energy release assembly which communicates with the air chamber, and is configured to introduce compressed air into the air chamber and release the compressed air; a working medium gas-liquid conversion assembly including a working medium compression assembly, a working medium expansion assembly and a liquid storage assembly; and a heat storage assembly, configured to release heat or store heat to the working medium gas-liquid conversion assembly.

Abstract: Disclosed is an unsupported hydrogenation catalyst, its preparation and application thereof. The unsupported hydrogenation catalyst is composed of a complex formed by bonding a metal central atom or central ion with an organic ligand through coordination bond, wherein the metal is selected from the group consisting of Group VB metals, Group VIB metals, Group VIII metals, Group IB metals or combinations thereof that have a hydrogenation activity. The organic ligand comprises a hydrocarbyl moiety and a coordinating group, and forms a coordination bond with the metal central atom or central ion through an oxygen atom. The unsupported hydrogenation catalyst can be used for hydrogenation reaction of hydrocarbons, and has high oil solubility, dispersibility and hydrogenation activity.

Abstract: Disclosed is a process and system for upgrading low-quality oils. The upgrading process comprises: (1) subjecting a low-quality oil to a conversion reaction in the presence of hydrogen and optionally in the presence of a conversion catalyst to obtain a conversion product, (2) processing the conversion product to obtain a first processed product, wherein the first processed product comprises a specific amount of a special component, and (3) subjecting the first processed product to extraction separation to obtain an upgraded oil and a pitch. The upgrading process and the upgrading system have the advantages of stable operation, high upgrading efficiency, environmental friendliness, low coke yield or high yield of upgraded oil.

Abstract: Disclosed is a process and system for upgrading low-quality oils. The upgrading process comprises: (1) subjecting a low-quality oil to a conversion reaction in the presence of hydrogen and optionally in the presence of a conversion catalyst to obtain a conversion product, (2) processing the conversion product to obtain a first processed product, wherein the first processed product comprises a specific amount of a special component, and (3) subjecting the first processed product to extraction separation to obtain an upgraded oil and a pitch. The upgrading process and the upgrading system have the advantages of stable operation, high upgrading efficiency, environmental friendliness, low coke yield or high yield of upgraded oil.