US 3,998,607 AGranted

Alkali metal catalyst recovery process

AssigneeExxon Research & Engineering Co.

InventorsRobert D. Wesselhoft, Charles J. Vadovic

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Abstract

A water-soluble alkali metal compound or other soluble constituent is recovered from a mixture of solid particles of different densities and the solid particles are simultaneously separated into two fractions, one having a greater density than the other by countercurrently contacting the solids with a leaching agent in which said constituent is soluble in a countercurrent multistage leaching system, maintaining the density of the enriched leaching agent in the final stage of the system at a value intermediate the densities of the particles in the mixture, and separately recovering enriched leaching solution, particles having a density greater than that of the enriched leaching solution, and particles with a density less than that of the enriched solution from the system. The process is particularly useful for the recovery of alkali metal constituents used to catalyze the gasification of coal and other carbonaceous solids.

Claims13

Dependent claims

A process for the recovery of alkali metal catalyst residues from a mixture of solid particles containing said alkali metal catalyst residues, carbonaceous solids, and particles of high ash content and for simultaneously separating said carbonaceous solids and particles of high ash content which comprises introducing said mixture of solid particles into the final stage of a countercurrent multistage leaching system having an initial stage and a final stage;

introducing an aqueous leaching agent into said initial stage of said leaching system;
passing particles of high ash content having densities greater than that of said leaching agent in said final stage and said leaching agent countercurrently through said leaching system;
withdrawing particles of high ash content which have densities greater than that of said leaching agent in said final stage and are substantially depleted of alkali metal catalyst residues soluble in said leaching agent from said initial stage of said system;
withdrawing leaching agent enriched in alkali metal catalyst residues soluble in said leaching agent from said final stage of said system;
maintaining the density of the enriched leaching agent within said final stage at an intermediate value between the density of said carbonaceous solids and said particles of high ash content in said mixture of solid particles introduced into said final stage;
and separately recovering carbonaceous solids having densities less that that of said leaching agent in said final stage from said final stage.

3 more elements

In a process for the production of a methane-containing gas wherein a carbonaceous solid is gasified in the presence of an alkali metal-containing catalyst, solids containing char particles, particles of high ash content, and alkali metal catalyst residues are produced, and alkali metal catalyst residues are recovered from said solids for reuse as a catalyst in the gasification process, the improvement which comprises introducing said solids into the final stage of a countercurrent multistage leaching system having an initial stage and a final stage;

introducing an aqueous leaching agent into said initial stage of said leaching system;
passing particles of high ash content having densities greater than that of said leaching agent in said final stage and said leaching agent countercurrently through said leaching system;
withdrawing particles of high ash content which have densities greater than that of said leaching agent in said final stage and are substantially depleted of alkali metal catalyst residues soluble in said leaching agent from said initial stage of said system;
withdrawing leaching agent enriched in alkali metal catalyst residues soluble in said leaching agent from said final stage of said system;
maintaining the density of the enriched leaching agent within said final stage at a value greater than the densities of said char particles but at a value less than the densities of said particles of high ash content;
separately recovering char particles which have densities less than that of said enriched leaching agent in said final stage of said system and therefore float on said enriched leaching agent in said final stage;
and recycling the recovered char particles for reuse in said gasification process.

4 more elements

Dependencies are inferred from the claim text.