Abstract: The present disclosure provides an internally self-circulating fluidized bed gasifier and an air distributor therein for generating a stepped constrained wind. The air distributor includes a gas-material mixture through hole and a plurality of vent holes. Each of the vent holes is designed to have a winding path. Due to the winding paths of the vent holes and an arrangement of converging outlets of the vent holes to the gas-material mixture through hole, which is in communication with a furnace chamber, the present disclosure enables a gas entering the furnace chamber to form a stepped constrained wind and effectively prevents solid-phase materials in the furnace chamber from leaking into a gas mixture chamber. The internally self-circulating fluidized bed gasifier can achieve self-circulation combustion gasification for multiple times and a well-controlled gasification temperature, resulting in a high coal gasification efficiency without an ash leakage.

Abstract: Provided are an efficient energy-saving return cylinder of a hydraulic press and a working method thereof. The efficient energy-saving return cylinder of a hydraulic press comprises a plurality of single-rod return hydraulic cylinders symmetrically distributed at two sides of a main hydraulic cylinder of the hydraulic press, the plurality of single-rod return hydraulic cylinders are divided into several groups, each of the groups consisting of one balancing cylinder and one driving cylinder; a rod chamber of the balancing cylinder is communicated with an accumulator, the pressurized oil in the accumulator is filled into an oil chamber of the balancing cylinder, so that the balancing cylinder balances the weight of a walking beam and a working part of the walking beam; the driving cylinder is differentially connected; in the process of neutral-stroke-rapid-descending and ascending-returning of the walking beam and the working part of the walking beam.