摘要:

AbstractIn response to increasing metal toxicity concerns, new and more stringent regulations are driving industry to better understand the fate of metals in the environment. As a result, practicing engineers need a set of tools for quickly understanding the aqueous chemistry of the system at hand. This paper presents a practical guide for estimating the solubility of metal hydroxides/oxides in aqueous systems. Equilibrium chemistry software from OLI Systems, Inc. (Morris Plains, NJ) was used to predict the solubility of metal hydroxides/oxides in water as a function of pH. The product is an overall metal solubility diagram containing the solubility curves for 12 metal hydroxides/oxides. The curves are based on a commercially available thermodynamic database and were validated against literature solubility data. In most cases, the curves depict the solubility of the less stable crystalline or amorphous form of the metal hydroxide or oxide. This will be typical of industrial situations where aging of the solid phase is often minimal. The solubility curves are best viewed as “solubility bands” that can extend as much as an order of magnitude above and below the predicted lines. Two case studies illustrate the usefulness of the overall metal solubility diagram to practicing engine

ISSN:0278-4491    

DOI:10.1002/ep.670170112

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170102

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170103

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170104

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170106

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractThe process air emissions from municipal wastewater treatment plants primarily consist of hydrogen sulfide gas, along with other organo‐sulfur compounds, and some trace quantities of volatile organic compounds, and some trace quantities of volatile organic compounds (VOC). Various Federal and/or State Regulations require monitoring, and control of these emissions down to some specified levels.At the Deer Island Wastewater Treatment Plant of the Massacbusetts Water Resources Authority (MWRA), air containing hydrogen sulfide is collected and treated in several emission control systems. These systems consist of wet scrubbers which facilitate destruction of hydrogen sulfide gas and the related odor by continuously contacting the collected air counter‐currently with a strong oxidizing solution of sodium hypochlorite.This paper reviews the performance of a typical scrubber in light of the theory of absorption followed by chemical reaction. Based on an analysis of a set of test data, it has been concluded that when the concentration of hydrogen sulfide at a scrubber inlet exceeds 25 ppm, the scrubber becomes mass transfer limited. This can lead to the incomplete oxidation of hydrogen sulfide gas. Unreacted H2S eventually can exit the scrubber while partially oxidized H2S, in the form of elemental sulfur, can deposit on, and eventually foul, the packing media. Measures taken to overcome such a situation have also been repor

ISSN:0278-4491    

DOI:10.1002/ep.670170113

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170109

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170110

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670170111

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY

摘要:

AbstractThe effects of various promoted and unpromoted mixed oxide catalysts on yields and compositions of liquid organic products as measured in a small laboratory pyrolysis reactor are reported. While such small‐scale results do not accurately predict process plant yields, they provide a useful reference in preliminary economic evaluations and in planning larger‐scale tests. Therefore, on the basis of laboratory results, a commercialscale catalytic pyrolysis plant for the production of synthetic crude oil was simulated by using Aspen Plus and the economics were developed. Depending on certain assumptions, such a process could be profitable. To test the possibility of producing chemicals, a separations plant was added. Simulation results again suggested potential economic viabil

ISSN:0278-4491    

DOI:10.1002/ep.670170114

出版商:American Institute of Chemical Engineers    

年代:1998

数据来源: WILEY