page 1059 |
Previous | 1 of 9 | Next |
|
|
Loading content ...
A NEW PROCESS FOR RECOVERING ACETIC ACID FROM DILUTE AQUEOUS WASTE STREAMS R. W. Helsel, Senior Environmental Engineer Hydroscience Environmental Systems Knoxville, Tennessee 37919 INTRODUCTION The fact that significant changes in the world economy took place about two years ago when the oil crisis hit is well known to everyone. The cost of petroleum soared, and so did the things that are derived from it, energy and chemicals. The environmental control scene also took on new perspective at that time. Increasingly more stringent waste discharge criteria were being promulgated by regulatory agencies, and industry was faced with the requirement to reduce its discharge of chemicals to the environment. It was only logical that environmental control activities be directed toward recovery processes. Whenever detailed characterization of industrial wastewaters has been carried out, one of the organic chemicals very commonly found in significant concentration is acetic acid (Table I). Depending on the source, acetic acid levels of Vi% to over 5% have been observed. In some cases its presence is expected since it is used as a solvent or raw material, as in acetylation and esterification reactions. But in many more cases its presence is unsuspected, yet it is found as a by-product of various processes. These include pulping of wood, organic chemical syntheses involving oxidation, and petrochemical processes which utilize severe conditions to crack or rearrange organic molecules or to recover them from shale or coal. When the thermodynamic stability of acetic acid is considered, and it is recognized that acetic acid is a stable end-product of organic degradation reactions, its wide-ranging occurrence in wastewaters becomes more understandable. In fact, it is estimated that a significant portion of the acetic acid consumed by industry today could be supplied by the acetic acid which is sewered or incinerated. Table 1. Sources of Acetic Acid in Industrial Wastewaters Direct Raw material (acetylation and esterification) Solvent losses Indirect (by-product) Wood pulping Oxidation reactions Severe petrochemical processes (coal conversion) Other chemical syntheses THE NEED FOR ACETIC ACID RECOVERY Advanced treatment of wastewaters containing significant levels of acetic acid to meet uture water quality standards is being recognized as much more difficult to achieve than MTVIOUslv thought. When acetic acid undergoes biological oxidation, approximately one- Jjalf of it is converted by the microorganisms to activated sludge. This sludge tends to nave poor settling characteristics and is difficult to dewater. The high conversion to a wet sludge makes ultimate disposal by incinceration expensive due to the large amounts o energy required. Optimistically, sludge incineration costs can be expected to be in ne range of 4 to 6 tf/lb of acid. Related to the need for adequate treatment, it should be pointed out that acetic acid is listed in the proposed EPA regulation for hazardous substances because of its environmental impact. 1059
Object Description
Purdue Identification Number | ETRIWC197696 |
Title | New process for recovering acetic acid from dilute aqueous waste streams |
Author | Helsel, R. W. |
Date of Original | 1976 |
Conference Title | Proceedings of the 31st Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,27048 |
Extent of Original | p. 1059-1067 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-08 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 1059 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | A NEW PROCESS FOR RECOVERING ACETIC ACID FROM DILUTE AQUEOUS WASTE STREAMS R. W. Helsel, Senior Environmental Engineer Hydroscience Environmental Systems Knoxville, Tennessee 37919 INTRODUCTION The fact that significant changes in the world economy took place about two years ago when the oil crisis hit is well known to everyone. The cost of petroleum soared, and so did the things that are derived from it, energy and chemicals. The environmental control scene also took on new perspective at that time. Increasingly more stringent waste discharge criteria were being promulgated by regulatory agencies, and industry was faced with the requirement to reduce its discharge of chemicals to the environment. It was only logical that environmental control activities be directed toward recovery processes. Whenever detailed characterization of industrial wastewaters has been carried out, one of the organic chemicals very commonly found in significant concentration is acetic acid (Table I). Depending on the source, acetic acid levels of Vi% to over 5% have been observed. In some cases its presence is expected since it is used as a solvent or raw material, as in acetylation and esterification reactions. But in many more cases its presence is unsuspected, yet it is found as a by-product of various processes. These include pulping of wood, organic chemical syntheses involving oxidation, and petrochemical processes which utilize severe conditions to crack or rearrange organic molecules or to recover them from shale or coal. When the thermodynamic stability of acetic acid is considered, and it is recognized that acetic acid is a stable end-product of organic degradation reactions, its wide-ranging occurrence in wastewaters becomes more understandable. In fact, it is estimated that a significant portion of the acetic acid consumed by industry today could be supplied by the acetic acid which is sewered or incinerated. Table 1. Sources of Acetic Acid in Industrial Wastewaters Direct Raw material (acetylation and esterification) Solvent losses Indirect (by-product) Wood pulping Oxidation reactions Severe petrochemical processes (coal conversion) Other chemical syntheses THE NEED FOR ACETIC ACID RECOVERY Advanced treatment of wastewaters containing significant levels of acetic acid to meet uture water quality standards is being recognized as much more difficult to achieve than MTVIOUslv thought. When acetic acid undergoes biological oxidation, approximately one- Jjalf of it is converted by the microorganisms to activated sludge. This sludge tends to nave poor settling characteristics and is difficult to dewater. The high conversion to a wet sludge makes ultimate disposal by incinceration expensive due to the large amounts o energy required. Optimistically, sludge incineration costs can be expected to be in ne range of 4 to 6 tf/lb of acid. Related to the need for adequate treatment, it should be pointed out that acetic acid is listed in the proposed EPA regulation for hazardous substances because of its environmental impact. 1059 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Tags
Comments
Post a Comment for page 1059