摘要:

AbstractPartenerships among business, government and environmental organizations show considerable promise for improving both the environment and the economic health of American business and industry. There is nothing more potent than a coalition of diverse interests. The author presents case studies based on his participation in partnerships involving General Motors (GM) and two environmental organizations. While environmental partnerships promise significant rewards, there are a number of challenges to be addressed, including entrenched adversarial attitudes and a regulatory paradigm that encourages business managers and government regulators alike to focus on paper “compliance” rather than real‐world performance. Overcoming these challenges will require that “win/lose” and “yes/no” be replaced by “win/win” and “how to.” It will require a new, market‐driven paradigm that fully integrates environmental considerations into the business planning process and that relies on economic incentives to encourage business managers and government regulators to seek out real sol

ISSN:0278-4491    

DOI:10.1002/ep.670150112

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150102

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150103

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractAbout twenty‐five percent of natural gas produced in the United States is sour containing significant volumes of hydrogen sulfide. Liquid redox processes remove hydrogen sulfide from natural gas. Aqueous solution of chelated ferric ions oxidize the hydrogen sulfide to elemental sulfur. The reduced iron chelate is then oxidized by contact with air and recycled. This requires expensive equipment for regeneration and the process is usually energy intensive.A microbial process for regeneration of chelated ferric ions may offer an economical alternative to commercial liquid redox processes. The present study investigates the use of a mixed culture of iron oxidizing bacteria to regenerate commercial iron chelate catalysts. The objective of this study is to quantify an increase in the biologically enhanced redox solution reoxidation rates. It was observed that the presence of bacterial cultures enhance the reoxidation rates and sulfur removal significantly. The proprietary mixed cultures of iron oxidizing bacteria used in this study derive the energy required for their growth from the oxidation of reduced sulfur compounds and from the oxidation of Fe(II) to Fe(III) ions in presence of air.A series of experiments were conducted with a commercial chelated iron catalyst at a constant pH of 7.5 using a total iron concentration of 1000 ppm in the solution. Regeneration of the solution was carried out by passing air through the solution. Sulfur produced was removed by centrifuging in the case of baseline experiments and by vacuum filtration in the presence of bacteria. A 50 to 125% increase was observed in the regeneration rates whereas sulfur yields were 80 to 100% of theoretical in the presence of bacteria as compared to 35 to 50% in the absence of bacteria. Iron oxidizing bacteria were used at cell densities of 1.5 × 109cells/l to be effective. The pH of the redox solution was observed to be a key process parameter. Other parameters such as temperature, total iron concentration, gas to liquid ratio and bacterial cell densities also influence the overall proce

ISSN:0278-4491    

DOI:10.1002/ep.670150113

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150104

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150107

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper presents studies of a new integrated process for simultaneous SOxand NOxremoval and utilization of waste carbonaceous materials. It is mainly centered on some fundamental aspects of preparing microporous adsorbents from solid wastes such as coal reject, sewage sludge and sawdust. Surface area and pore structural evolution are investigated to illustrate the importance of processing parameters such as pyrolysis temperature and hold time, activation methods and carbon burn‐off, etc. It is shown that pyrolysis temperature, activation chemicals used and carbon burn‐off have significant effects on the surface area development and pore structure evolution. There exist an optimal pyrolysis temperature and hold time for maximum surface area development for all precursor materials. Physical activation of coal reject char after pyrolysis can improve the surface area of the derived chars, while chemical treatment in ZnCl2can enhance the microporosity of sewage sludge char. In physical activation, carbon burn‐off or hold time is a critical factor in determining the surface area. Concentration of the activating agent is an important factor in chemical treatment of sewage sludge. Adsorption characteristics of the wastes‐derived adsorbents with respect to SO2, H2S, and NOxare also studied in this work. It is shown that solid wastes such as sawdust and coal mining wastes can be converted into effective adsorbents for SO2and NOxremoval from the flue gases, whilst activated chars derived from sewage sludge have been shown to be promising adsorbents for H2S removal. The significance of using waste solids is two‐fold: on one hand the waste materials are utilized or minimized; on the other, they can replace or partially substitute the expensive activated carbons for the removal of S

ISSN:0278-4491    

DOI:10.1002/ep.670150114

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150109

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150110

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150111

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY