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Recovery or Destruction — New Developments for Industrial Wastes R.D. FOX, Group Leader K.J. HIMMELSTEIN, Senior Research Engineer The Dow Chemical Company Midland, Michigan 48640 INTRODUCTION The chemical process industries have long practiced the recovery of products and byproducts from the various solid, liquid and gaseous effluents of their manufacturing processes. In the past the feasibility of carrying out these recovery steps as part of the manufacturing process has been determined largely on the basis of economics. Only if the operations required for recovery could result in the desired return on the investment was the recovery process ultimately incorporated in the overall design. In recent years, a new dimension has been added to the measurement of chemical recovery feasibility. Concern for the environment and its improvement has brought about the need in the chemical industries for improved manufacturing processes and equipment and for a higher degree of purification of their effluents. The treatment of industrial wastes to remove soluble organic chemicals has always involved decisions requiring a comparison of systems providing recovery with those based on destruction, and selection of an optimum method. The recent escalations in the value of organic chemicals and their shortage, as well as the rising costs of energy and shortages of fuels, make recovery considerations even more important. The Dow Chemical Company has for many years been committed to maximizing product recovery and effluent purification while minimizing energy consumption. Recovery of organic chemicals from aqueous effluents requires some method of physical separation of the chemicals from the bulk of the waste. One of the most efficient methods available for the separation of organic chemicals from wastewater is adsorption, especially on activated carbon. Activated carbon is unique among adsorbents in its capability to adsorb a wide variety of industrial organic molecules from both liquids and gases. It can remove them with a loading or organic per unit weight of carbon typically in the range of 0.1 to 1.0. The removal is quite efficient, easily producing an effluent with 1 ppm organic in a properly designed system. Only in cases where the molecule is very small or very large does activated-carbon fail to perform adequately, and it has long been used to purify water, wastewater and air. In aqueous applications, recovery of the adsorbed chemicals has received little attention. Most activated-carbon adsorption systems, in dealing with the problem of what to do with the saturated or spent carbon, either discard the spent carbon or reactivate it in a special thermal regeneration furnace, burning off the adsorbed chemicals in a controlled atmosphere. The latter is more efficient from a carbon usage standpoint but still involves carbon losses of 5-10% per cycle. This cost can be prohibitive when considered for industrial waste purification. Industrial wastes are typically high strength, containing large concentrations of organic chemicals. Activated carbon thus saturates quickly, and cycle times are short, requiring frequent carbon regeneration. If thermal regeneration is used, carbon makeup costs are prohibitively high; as a result, industrial waste treatment systems have been unable to fully utilize the capabilities of activated carbon. 445
Object Description
Purdue Identification Number | ETRIWC197443 |
Title | Recovery or destruction :new developments for industrial wastes |
Author |
Fox, Robert D. Himmelstein, K. J. |
Date of Original | 1974 |
Conference Title | Proceedings of the 29th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,24462 |
Extent of Original | p. 445-455 |
Series | Engineering extension series no. 145 |
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 | 2009-06-05 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page445 |
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 | Recovery or Destruction — New Developments for Industrial Wastes R.D. FOX, Group Leader K.J. HIMMELSTEIN, Senior Research Engineer The Dow Chemical Company Midland, Michigan 48640 INTRODUCTION The chemical process industries have long practiced the recovery of products and byproducts from the various solid, liquid and gaseous effluents of their manufacturing processes. In the past the feasibility of carrying out these recovery steps as part of the manufacturing process has been determined largely on the basis of economics. Only if the operations required for recovery could result in the desired return on the investment was the recovery process ultimately incorporated in the overall design. In recent years, a new dimension has been added to the measurement of chemical recovery feasibility. Concern for the environment and its improvement has brought about the need in the chemical industries for improved manufacturing processes and equipment and for a higher degree of purification of their effluents. The treatment of industrial wastes to remove soluble organic chemicals has always involved decisions requiring a comparison of systems providing recovery with those based on destruction, and selection of an optimum method. The recent escalations in the value of organic chemicals and their shortage, as well as the rising costs of energy and shortages of fuels, make recovery considerations even more important. The Dow Chemical Company has for many years been committed to maximizing product recovery and effluent purification while minimizing energy consumption. Recovery of organic chemicals from aqueous effluents requires some method of physical separation of the chemicals from the bulk of the waste. One of the most efficient methods available for the separation of organic chemicals from wastewater is adsorption, especially on activated carbon. Activated carbon is unique among adsorbents in its capability to adsorb a wide variety of industrial organic molecules from both liquids and gases. It can remove them with a loading or organic per unit weight of carbon typically in the range of 0.1 to 1.0. The removal is quite efficient, easily producing an effluent with 1 ppm organic in a properly designed system. Only in cases where the molecule is very small or very large does activated-carbon fail to perform adequately, and it has long been used to purify water, wastewater and air. In aqueous applications, recovery of the adsorbed chemicals has received little attention. Most activated-carbon adsorption systems, in dealing with the problem of what to do with the saturated or spent carbon, either discard the spent carbon or reactivate it in a special thermal regeneration furnace, burning off the adsorbed chemicals in a controlled atmosphere. The latter is more efficient from a carbon usage standpoint but still involves carbon losses of 5-10% per cycle. This cost can be prohibitive when considered for industrial waste purification. Industrial wastes are typically high strength, containing large concentrations of organic chemicals. Activated carbon thus saturates quickly, and cycle times are short, requiring frequent carbon regeneration. If thermal regeneration is used, carbon makeup costs are prohibitively high; as a result, industrial waste treatment systems have been unable to fully utilize the capabilities of activated carbon. 445 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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