摘要:

AbstractAn innovative cleanup concept, based on a Confined Vortex Scrubber (CVS), for fine particulate removal from combustion flue gases has been developed, tested and verified. The CVS consists of a cylindrical vortex chamber with multiple tangential flue gas inlets. The clean gas exit is via two central tubes. Water is introduced into the chamber and is confined within the vortex chamber by the extremely high centrifugal forces generated by the gas flow. The confined water forms a layer through which the flue gas is forced to bubble. Due to the high radial acceleration, the bubbles generated are very small, leading to a strong gas/liquid interaction, high inertial separation forces and extremely efficient fine particle cleanup. Collection efficiencies in excess of 99.5 percent have been measured for extremely fine fly ash (mean particle size 3 microns). A collection efficiency of 98 percent has been measured for 0.3 micron diameter particles.

ISSN:0278-4491    

DOI:10.1002/ep.670110114

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractThe SOx‐NOx‐Rox BoxTM(SNRB) is an advanced air pollution process patented by Babcock&Wilcox (B&W) that provides for significantly reduced sulfur oxides (SOx), nitrogen oxides (NOx), and particulate emissions from coal‐fired boilers. The process uses a high‐temperature catalytic baghouse for integrating SOxreduction through injecting an alkali sorbent (such as hydrated lime or sodium bicarbonate), NOxremoval through ammonia injection and selective catalytic reduction (SCR), and particulate collection. The advantages of the process include: compact integration of the emission control technologies into a single component; dry sorbent and by‐product handling; and improved SCR catalyst life due to lowered SOxand particulate levels.The SNRB concept has been successfully demonstrated in a 1500‐ACFM pilot baghouse at B&W's Alliance (Ohio) Research Center. This paper describes the SNRB technology and presents the SOx, NOx, and particulate removal performance results over a range of operating conditions for the laboratory pilot t

ISSN:0278-4491    

DOI:10.1002/ep.670110115

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractConsiderations for evaluating and designing the air stripping process are presented by case study. The case study involves the design of an air stripping process to remediate groundwater contaminated with volatile organic compounds (VOCs) at a National Priorities List site in Tacoma, WA. Design objectives included developing a tower with minimum volume and energy requirements while complying with discharge air and water quality standards. A two‐phase resistance model using Onda correlations to determine liquid‐ and gas‐phase resistance model using Onda correlations to determine liquid‐ and gas‐phase mass transfer coefficients was used to assist in the evaluation and design.Considerations for applying the two‐phase resistance model to air stripping tower design are presented. The ability of the model to simulate process performance is demonstrated by comparison with actual data for 11 priority pollutant list VOCs evaluated during an onsite pilot study. Design procedures with which to develop a tower with minimum volume and energy requirements are described. Other considerations involving the evaluation of VOC emissions and the precipitation and buildup of inorganic constituents within the internal packing media ar

ISSN:0278-4491    

DOI:10.1002/ep.670110116

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractContinuous Deionization (CDI)—also known as electrodeionization—is a hybrid separation process combining ion‐exchange resins and ion‐exchange membranes. A voltage gradient is used as the driving force for separations. The process is capable of acieving high levels of purification and concentration of dissolved ionic solutes without the use of chemical regenerants. Early research in the field focussed on the removal and concentration of trace metals from effluent streams. In CDI equipment, the electrical conductivity of only the diluting compartments is enhanced by the ion‐exchange packing. For this reason, purification levels often improve as the water recovery increases. Examples of improved performance are provided as measured by water conductivity, and levels of dissolved carbon dioxide.In high purity water production, concentration ratios of 1,000 to over 10,000 are achieved at high electrical efficiency. The process is therefore well‐suited for liquid purification applications requiring a high extent of deionization coupled with a high concentration, low volume concentrate stream with no net chemical additives. Using a municipal water source, purification levels, as measured by electrical conductivity, of 10 to 0.1 microsiemens/cm are achievable at 75–80% water recovery. Recovery is limited primarily by the precipitation of solids in the concentrating stream. In specialized applications, e.g., for production of less than 0.1 microsiemens/cm ultra‐pure water downstream of reverse osmosis (RO), CDI product water recoveries of 95% are achievable. Typical flow diagrams are provide

ISSN:0278-4491    

DOI:10.1002/ep.670110117

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractWurtsmith Air Force Base is the site of an air‐stripping‐with‐emissions‐control system to remove volatile organic compounds (VOCs), chiefly trichloroethylene (TCE), from groundwater. The purpose of this study was to evaluate the performance of a fluidized‐bed catalytic oxidation unit for destroying halogenated organics with respect to catalyst bed temperature and operating time. The objectives included identification of any products of incomplete combustion formed and determination of the utility costs for the unit. Samples were collected over a period of ∼ 19 months with volatile organic sampling trains according to the Environmental Protection Agency (EPA) Method 30. Samples were taken at catalyst bed temperatures of 315, 370, 425, and 480°C. The results indicate that the incinerator was destroying the TCE with<97% efficiency when operated at ≥370°C. A conservative cost estimate for utilities was determined to be $0.36/1000 gal o

ISSN:0278-4491    

DOI:10.1002/ep.670110118

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper discusses the control of benzene emissions from a petroleum refinery as regulated by the National Emission Standards for Hazardous Air Pollutants (NESHAP) Subpart FF—National Standard for Benzene Waste Operations (40 CFR Part 61.340). This regulation is complex and confusing, but it provides flexibility to achieve compliance through various strategies to control benzene emissions.The first step to achieve compliane with the benzene waste NESHAP is understanding the regulation itself. Therefore, this paper summarizes the regulation to provide the reader with sufficient background to understand why specific controls are required for specific processes. The flexibility provided by the regulation to achieve compliance is not always readily apparent. This paper summarizes some of these subtleties. The author's involvement with an industry trade association in meetings with the Environmental Protection Agency (EPA) during the development of the regulation allows some of EPA's expressions of their intent and internal interpretation to also be contained in the summary. The second step to achieve compliance with the benzene waste NESHAP is to actually design and operate a cost effective solution for a specific set of existing conditions within a refinery. This paper provides a case study of the equipment necessary to achieve compliance with the substantive requirements of the regulation at a large, integrated refinery. The retrofit requirements are very specific to the circumstances of this facility. Therefore, they will not be a universal, cost effective means of compliance for other refinerie

ISSN:0278-4491    

DOI:10.1002/ep.670110119

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractThe addition of yellow phosphorus in wet scrubbing systems can result in the high efficiency simultaneous removal of SO2and NOxfrom flue gas. Yellow phosphorus reacts with O2to produce O3which selectively oxidizes NO to NO2. Subsequently, NO2and SO2are removed from flue gas by dissolution into an aqueous alkaline solution/slurry, where they are converted to ammonium sulfate and gypsum. Yellow phosphorus is oxidized to yield a desirable commercial by‐product, phosphoric acid.This new technology has been tested jointly by LBL and Bechtel at LBL with a 20 cfm [9.44 × 10−3m3/ sec] bench‐scale scrubbing absorber. The test results indicated that greater than 90% NO removal efficiency could be achieved with an L/G>60 (gal/min)/(1000 cu ft/min) [1 liter/m3= 7.48 gal/1000 cu ft] for NO concentrations ranging from 60 to 600 ppm. A stoichiometric ratio, P/NO, as low as 0.6 has been achieved. Economic projections for the PhoSNOX process have been made based on a conceptual process configuration. The estimated costs compare favorably with the SCR for high removal and are competitive with urea injection processes for low levels of NOxremoval. FMC has conducted a safety study of the process and concluded that the potential safety hazards of yellow phosphorus can be avoided if proper precautions are

ISSN:0278-4491    

DOI:10.1002/ep.670110120

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractApplication of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook‐Simon‐Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro‐osmosis due to the application of a direct current field. Electro‐osmosis is caused by an electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro‐osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activat

ISSN:0278-4491    

DOI:10.1002/ep.670110121

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractThe Hoechst Celanese facility in Narrows, Virginia, treats process wastewater in an aerobic biological wastewater treatment plant (WWTP). Historically, the WWTP has experienced high effluent TSS levels. When the facility's National Pollutant Discharge Elimination System (NPDES) permit is modified, more stringent effluent TSS limits will be incorporated based on the OCPSF effluent guidelines. Without significantly improved effluent quality, effluent filtration will be required. At the historical effluent TSS levels experienced by the WWTP, conventional filters will not provide the reliability needed for permit compliance. In 1990, influent sampling indicated that the poor effluent quality could be the result of nutrient limitations. Nitrogen was identified as a limiting macronutrient, but effluent quality did not substantially improve when only nitrogen additions were increased. After a program was implemented to add micronutrients concurrently, effluent quality significantly improved. It was concluded that micro‐ and macro‐nutrient additions coupled with effluent filtration will be required to meet the future OCPSF TSS lim

ISSN:0278-4491    

DOI:10.1002/ep.670110122

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110101

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY