Abstract: A high temperature air heater including a heat transfer conduit located in higher temperature gas. The heat transfer conduit is made up of a heat transfer pipe through which the air to be heated flows and a refractory protective pipe covering the heat transfer pipe. A clearance is provided between the heat transfer pipe and the refractory protective pipe. The clearance makes it possible to accommodate the differences in thermal expansion between the heat transfer pipe and the refractory protective pipe to prevent damaging the refractory protective pipe, thus extending the service life of the high temperature air heater.

Abstract: In an air heater for use in recovering, by heat exchange, the heat of an exhaust gas generated from an incinerator for disposing of wastes, prolonged service life and improved working efficiency are attainable with least thermal deformation. The air heater has a heat transfer conduit which is placed in high temperature highly corrosive gas.

Abstract: In an apparatus for heating high-temperature air for use in recovering, by heat exchange, the heat of an exhaust gas of elevated temperature generated from an apparatus for disposing of wastes, prolonged service life, improved working efficiency, improved efficiency of heat recovery on heat exchange are attainable with least thermal deformation and reduced dust deposition.

Abstract: A high-concentration coal-water slurry of a coal concentration as high as 71 percent by weight at a viscosity of 2,000 cp (at 25.degree. C.) can be produced by first coarsely crushing a starting coal, further pulverizing 95 to 30 percent by weight of the coarsely crushed thus obtained, subjecting the finely pulverized coal thus obtained, together with the remainder of the coarsely crushed coal, to crushing in a wet-type crusher, and pulverizing and adjusting the coal particles to a particle size constitution of 20 to 30 percent by weight of 200-mesh size and larger and 80 percent by weight or less of 350-mesh size and smaller.

Abstract: A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof.

Abstract: High concentrated coal-water slurry is produced by coarsely crushing coal, thereafter pulverizing the coarsely crushed coal, together with water and a slurry dispersant, according to necessity, in a wet-type ball mill, and feeding back one portion of the finely pulverized coal slurry thus obtained into the inlet of the wet-type ball mill.

Abstract: An exhaust gas heat recovery system wherein:the system comprises an exhaust gas economizer having of heat transfer sections including a preheating section, an evaporating section and a superheating section, a feed water heater, a steam separation drum, a low pressure steam generator; and a mixed-pressure turbine;a temperature gradient of circulating water and a temperature gradient of exhaust gases are made substantially equal to each other in the preheating section of the exhaust gas economizer to prevent an exhaust gas economizer tube from being corroded by generated sulfuric acid; andlow pressure steam can be effectively utilized by use of the mixed-pressure turbine.