Method for generating steam

Abstract

Disclosed is a method for generating steam from water containing high concentrations of particulate matter such as silt, clay, etc., without the need for filtering and otherwise treating the water prior to generation of steam therefrom, especially useful for use in a viscous oil recovery process. The method comprises introducing solid particulate materials such as coarse sand, etc., into a thermal cracking unit such as, for example, that is used in the Lurgi-Ruhrgas process. The solids are heated to a temperature of at least 1400.degree. F., and on contacting the crude, cause cracking of the viscous crude into lighter molecular weight hydrocarbons and form a solid coke-like residue on the sand grain. The sand grains containing the coke residue are transported into a second chamber into which air is injected and the solid coke residue ignited. The carbon coke residue burns, raising the temperature of the sand or other granular solids. A portion of the hot solids are recycled into the thermal cracking unit, and another portion are transported to a steam generator unit into which dirty water, e.g., water containing high concentrations of suspended particulate matters such as sand, clay, silt, etc. is introduced. The rate of hot solids introduction and water injection into the steam generating unit are controlled so as to produce steam of the desired quality for use in a steam injection viscous oil recovery method.