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Section 12. COAL, COKE, AND POWER PLANT WASTES EDS COAL LIQUEFACTION WASTEWATERS: ZERO-DISCHARGE TREATABILITY STUDIES Stan A. Kaczmarek, Project Engineer Francis L. Robertaccio, Engineering Associate Exxon Research and Engineering Company Florham Park, NJ 07932 INTRODUCTION This paper describes research to verify the commercial readiness of a zero-discharge treatment scheme for wastewaters produced by the EDS coal liquefaction process. The potential need to operate with zero-discharge wastewater is due to the uncertainty of future regulations and the possibility that these industries would be located in arid regions where water reuse is desirable. The EDS process, outlined in Figure 1, was proposed in the later 1960s. It directly converts coal to a range of clean hydrocarbon products by contacting the coal with hydrogen in the presence of a hydrogenated donor solvent. The commercial readiness of this technology has recently been demonstrated for certain coals and operating conditions under a jointly funded government/industry development effort. The effort included testing of two pilot plants: a batch-fed 1 metric ton per day unit called CLPP in 1978, and a 225 metric ton per day, continuous feed prototype unit called ECLP during 1981 and 1982. Wastewater characterization and treatability tests were included in both of these efforts. Earlier studies on pollution control in the EDS process focused on wastewater reduction schemes, as well as characterization and treatability of samples collected from CLPP. Those results have been presented elsewhere [1]. This paper provides results of more recent and more detailed treatability studies performed on wastewaters collected from ECLP, which is considered to be scaleable to commercial size for those parts of the process represented in ECLP (coal preparation, liquefaction, solvent hydrogenation and fractionation). The characteristics of EDS process wastewaters are detailed in Table I. Raw process wastewaters contain considerable levels of acid gases, ammonia, organic compounds, and inorganics consistent with minerals in the feedstock. The major raw wastewater organic contaminants are phenolics, not unlike other coal conversion wastewaters. There are also large amounts of organic acids, and lesser quantities (e.g., 100 to 1000 mg/1) of aldehydes, ketones and various organo-nitrogen and sulfur compounds. ZERO-DISCHARGE TREATMENT SCHEME The zero-discharge treatment scheme chosen for this study is shown in Figure 2. Its goal is to consistently produce water suitable for use as cooling tower makeup. The cooling tower services heat exchangers are part of the EDS process equipment. A shortened version of this train might meet regulated discharge limits in a location where wastewater discharge was allowed, or short water supplies did not require reuse. The first treatment step, two-stage sour water stripping, removes hydrogen sulfide, carbon dioxide, and ammonia. Caustic injection in the second stage is necessary to free ammonia that appears "fixed" in the water (i.e., not easily stripped). 509
Object Description
Purdue Identification Number | ETRIWC198353 |
Title | EDS coal liquefaction wastewaters: zero-discharge treatability studies |
Author |
Kaczmarek, Stan A. Robertaccio, Francis L. |
Date of Original | 1983 |
Conference Title | Proceedings of the 38th Industrial Waste Conference |
Extent of Original | p. 509-518 |
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 | 2009-07-28 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 509 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Section 12. COAL, COKE, AND POWER PLANT WASTES EDS COAL LIQUEFACTION WASTEWATERS: ZERO-DISCHARGE TREATABILITY STUDIES Stan A. Kaczmarek, Project Engineer Francis L. Robertaccio, Engineering Associate Exxon Research and Engineering Company Florham Park, NJ 07932 INTRODUCTION This paper describes research to verify the commercial readiness of a zero-discharge treatment scheme for wastewaters produced by the EDS coal liquefaction process. The potential need to operate with zero-discharge wastewater is due to the uncertainty of future regulations and the possibility that these industries would be located in arid regions where water reuse is desirable. The EDS process, outlined in Figure 1, was proposed in the later 1960s. It directly converts coal to a range of clean hydrocarbon products by contacting the coal with hydrogen in the presence of a hydrogenated donor solvent. The commercial readiness of this technology has recently been demonstrated for certain coals and operating conditions under a jointly funded government/industry development effort. The effort included testing of two pilot plants: a batch-fed 1 metric ton per day unit called CLPP in 1978, and a 225 metric ton per day, continuous feed prototype unit called ECLP during 1981 and 1982. Wastewater characterization and treatability tests were included in both of these efforts. Earlier studies on pollution control in the EDS process focused on wastewater reduction schemes, as well as characterization and treatability of samples collected from CLPP. Those results have been presented elsewhere [1]. This paper provides results of more recent and more detailed treatability studies performed on wastewaters collected from ECLP, which is considered to be scaleable to commercial size for those parts of the process represented in ECLP (coal preparation, liquefaction, solvent hydrogenation and fractionation). The characteristics of EDS process wastewaters are detailed in Table I. Raw process wastewaters contain considerable levels of acid gases, ammonia, organic compounds, and inorganics consistent with minerals in the feedstock. The major raw wastewater organic contaminants are phenolics, not unlike other coal conversion wastewaters. There are also large amounts of organic acids, and lesser quantities (e.g., 100 to 1000 mg/1) of aldehydes, ketones and various organo-nitrogen and sulfur compounds. ZERO-DISCHARGE TREATMENT SCHEME The zero-discharge treatment scheme chosen for this study is shown in Figure 2. Its goal is to consistently produce water suitable for use as cooling tower makeup. The cooling tower services heat exchangers are part of the EDS process equipment. A shortened version of this train might meet regulated discharge limits in a location where wastewater discharge was allowed, or short water supplies did not require reuse. The first treatment step, two-stage sour water stripping, removes hydrogen sulfide, carbon dioxide, and ammonia. Caustic injection in the second stage is necessary to free ammonia that appears "fixed" in the water (i.e., not easily stripped). 509 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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