# US 5,346,630 A · Coal dewatering

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- Number: US 5,346,630 A
- Document ID: US5346630A
- Status: Granted
- Kind: A
- Application number: 07/961,904
- Filed: 1993-03-15
- Granted: 1994-09-13
- Earliest claimed: 1990-05-08
- Assignees: Unilever Patent Holdings B.V.
- Inventors: Mark E. Kenney
- Web page: https://patentgrep.com/patent/US5346630A

## CPC

- B01D 12/00: Displacing liquid, e.g. from wet solids or from dispersions of liquids or from solids in liquids, by means of another liquid
- B01D 37/03: using flocculating agents
- F26B 5/005: {by dipping them into or mixing them with a chemical liquid, e.g. organic; chemical, e.g. organic, dewatering aids (F26B3/005 takes precedence; using chemical vapours or gases F26B21/40)}
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F26B: DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM (drying devices for combines A01D41/133; racks for drying fruit or vegetables A01F25/12; drying foodstuffs A23; drying hair A45D20/00; body-drying implements A47K10/00; drying household articles A47L; drying gases or vapours B01D; chemical or physical processes for dewatering or like separating liquids from solids B01D43/00; centrifugal apparatus B04; drying ceramics C04B33/30; drying yarns or fabrics in association with some other form of treatment D06C; drying frames for laundry without heating or positive air circulation, domestic laundry-or spin-driers, wringing or hot pressing laundry D06F; furnaces, kilns, ovens F27)

## Abstract

In the vacuum filtering of coal slurries, dewatering of the filter cake is achieved by contacting the coal with a C.sub.8 to C.sub.20 aliphatic carboxylic acid or a derivative thereof, especially sodium oleate. Reductions in moisture levels are thereby achieved in a cost-effective manner.

## Claims

### Claim 1

A process for dewatering an aqueous coal slurry filter cake comprising spraying the coal slurry filter cake with at least 5 g per tonne of filtered coal of a dewatering aid consisting essentially of a C.sub.8 to C.sub.20 aliphatic carboxylic acid or a derivative thereof selected from esters, amides and salts of fatty acids and applying a pressure differential across the cake to remove water therefrom.

### Claim 2 (depends on 1)

A process according to claim 1, wherein the aliphatic carboxylic acid derivative is a salt of a fatty acid formed in situ by the addition of alkali together with a fatty acid.

### Claim 3 (depends on 1)

A process according to claim 1, wherein the dewatering aid is added at a concentration of from 50 to 1000 g per tonne of filtered coal.

### Claim 4 (depends on 1)

A process according to claim 1, wherein the dewatering aid is added in the form of an aqueous solution having a concentration of from 1 g/l to 10 g/l.

### Claim 5 (depends on 1)

A process according to claim 1, wherein the dewatering aid is sodium oleate.