# US 4,398,046 A · Glycol purification with minimal pH drop

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- Number: US 4,398,046 A
- Document ID: US4398046A
- Status: Granted
- Kind: A
- Application number: 06/366,439
- Filed: 1982-04-07
- Granted: 1983-08-09
- Earliest claimed: 1982-04-07
- Assignees: Calgon Carbon Corporation
- Inventors: Michael R. Rosene
- Web page: https://patentgrep.com/patent/US4398046A

## CPC

- B01D 15/00: Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D 15/267: {using neutral sorbents, e.g. activated carbon or diatomaceous earth}
- C07C 29/86: by liquid-liquid treatment
- 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)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Standard activated carbons have been commonly employed in the purification of contaminated glycol scrubbing solutions used in a liquid-liquid extraction process for the manufacture of petrochemicals. These carbons are shown to cause a depression of pH within the glycol stream when a new carbon type is installed or when the exhausted carbon is replaced. The use of a magnesite containing activated carbon minimizes this pH drop to acceptable levels.

## Claims

### Claim 1

In the purification of contaminated glycol scrubbing solutions used in a liquid-liquid extraction process for the manufacture of petrochemicals by passage of said glycol solutions through an activated carbon filter, the improvement comprising minimizing glycol pH reduction by: employing a magnesite containing activated carbon.

### Claim 2 (depends on 1)

The improved process of claim 1 wherein the pH reduction of the glycol solution is to not less than 6.0.

### Claim 3 (depends on 1)

The improved process of claim 1 wherein the magnesite containing activated carbon is up to 15.0 weight percent MgO based on the weight of activated carbon.

### Claim 4 (depends on 1)

The improved process of claim 1 wherein the magnesite containing activated carbon is from about 5 to 10 weight percent MgO.

### Claim 5 (depends on 1)

The improved process of claim 1 wherein the magnesite containing activated carbon is from about 5 to 10 weight percent dead-burned magnesite.

### Claim 6 (depends on 1)

The improved process of claim 1 wherein the magnesite containing activated carbon is from 0.1 to 5.0 weight percent MgO.

### Claim 7 (depends on 1)

The improved process of claim 1 wherein the magnesite containing activated carbon is from 0.1 to 5.0 weight percent dead-burned magnesite.