Abstract: An apparatus for effectively making the supply of material slurry at a high pressure into a high-pressure liquefaction reaction vessel and relief of the pressure of the high-pressure product slurry to permit the discharge of the product slurry as a low-pressure slurry. At least one cylinder having a float therein is used. The material slurry is charged at a low pressure into the cylinder from one end of the latter. Then, the high-pressure product slurry after the reaction is charged from the other end of this cylinder or another cylinder so that the material slurry is pressurized and forcibly supplied to the reaction vessel by the high pressure possessed by the high-pressure product slurry.

Abstract: In a fluidized bed reactor having a reactor vessel, two detector vessels are mounted in the reactor vessel near the inside surface of the reactor vessel in the fluidized bed and in the gas outlet region. Each detector vessel contains larger detecting particles and passes the gas in the reactor vessel. Pressure drop across the detecting particles is measured. The ratio of the two pressure drops represents the ratio of the fluid velocity and minimum fluidizing velocity under the operating conditions and can be used as control factor.

Abstract: A catalyst suitable for cracking heavy oils can be obtained by baking nickel-containing ore at a temperature between about 850.degree. C and about 1200.degree. C.