摘要:

AbstractThe Predictive Emissions Monitoring System (PEMS) has been recently proposed as an alternative to hardware continuous emissions monitors (CEM). PEMS has two distinct advantages over hardware CEM: much lower costs to install and maintain, and ability to provide information on emissions under various conditions. Using a state‐of‐the‐art computer program, an accurate PEMS was developed for an ethylene furnace at Exxon Chemical Company's Baytown Olefins Plant, Baytown, Texas. First, a test plan was carefully designed to collect furnace process and stack emissions data over the total operating range of the furnace. The emissions data (NOx, O2and CO) were collected and measured by an independent company for 5 days. The related process data were recorded in the DCS system during the same 5‐day period. A dataset with some 7,000 patterns of related process and emissions data was generated. The PEMS system contains 2 parts: emissions prediction and sensor validation models. The main purpose of the sensor validation model is to validate the input sensor's raw data and reconstruct new sensor values, if necessary, before they are used in the prediction model. Its usage provides a high degree of confidence for the PEMS system. Two separate emissions prediction models were built, one for NOxand O2, and the other for CO. Both final models have the same 9 input sensors. A PEMS relative accuracy test audit (RATA) was performed by an independent company to test the PEMS system under the three firing rate conditions (low, medium, and high). Test results indicate that the PEMS system satisfied both the relative accuracy (RA) and the stringent statistical test requirements including the F‐test, t‐test and r

ISSN:0278-4491    

DOI:10.1002/ep.670150115

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractA water pollution prevention study was performed for two plating processes at Lawrence Berkeley National Laboratory (LBNL). This study included wastewater precipitation process analysis, and evaluation of separation and recycling alternatives. One of the pollution prevention opportunity assessment goals is to reduce and reuse wastewater.From a review of coordination chemistry and a series of precipitation process tests, it was found that treatment with optimized pH and mixing rate, proper coprecipitans (such as iron salts), and chemical dosages were needed to dissociate metal ions from the complexes in the wastewater. In this study, reverse osmosis and ion exchange technologies were also evaluated. A water reclamation analysis with these two technologies was implemented. The analysis projected, that with recycling systems, 33% of the wastewater could be reclaimed.

ISSN:0278-4491    

DOI:10.1002/ep.670150116

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractA low‐energy dechlorination technique has been applied to the detoxification of chlorinated hydrocarbons (CHCs) in aqeous solution. This alternative to biological or physco‐chemical decomposition methods achieves reduction by means of metal particles or copper‐activated metal particles (Mg, Fe, Al, Zn).The paper presents data from two pilot studies, covering fundamental process design aspects. Experimental investigations of pilot study 1 were conducted in a laboratory‐scale fixed bed reactor. In weak acidic or neutral medium (pH‐range 4–7) proper process application resulted in very rapid removal of hexacholorocyclohexane concentration (γ – BHC, lindane) from model wastewaters with up to 99.3% efficiency. During the course of reaction the main products formed are chloride and benzene, the by‐product being small amounts of chlorobenzene. After employing different metals in the dechlorination reaction zinc proved to be the optimum reducing agent since it achieved the best space‐time yield. Pilot study 2 dealt with a couple of screening reactions of various CHCs with zinc as the reducing agent, which were performed in the batch mode. Even volatile CHCs (chloroform, 1, 1, 1‐trichloroethane) could be completely dechlorinated by forming the corresponding hydrocarbons (methane; ethane and ethene respectively). Pseudo‐first order rate constants (k, s−1) were determined to assess substrate reactivity with respect to possible process ap

ISSN:0278-4491    

DOI:10.1002/ep.670150117

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractA batch reactor designed to simulate the non‐isothermal temperature profile of a commercial, vertical‐tube wet oxidation process is used to predict global process performance, and to estimate reaction rates. A model is developed for the batch reactor that predicts extent of reaction and vapor/liquid equilibria under non‐isothermal conditions. This model is used with measured rate parameters to predict the effect of process conditions on overall performance of specific wastes. This reduces the number of runs normally executed in a feasibility study, saving time and money. Phenol is selected as a model compound, and values for reaction rate constants and induction period length are obtained for temperatures up to

ISSN:0278-4491    

DOI:10.1002/ep.670150118

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractThe goal of this research is to show that source reduction through process modification is a viable technique to minimize process waste. To accomplish this objective, the allyl chloride process was studied. The approach involved three steps: process modeling, selection of source reduction variables and their ranges, and optimization of an economic objective function. The simulator ASPEN PLUS™ was used to model and evaluate the process. Source reduction variables were primarily located through the literature as well as a sensitivity analysis. To find the best value of these process variables, optimization of an economic objective function was performed. The general methodology developed through this work gave structure to this research and was found to be a useful approach in determining economical waste minimization optic

ISSN:0278-4491    

DOI:10.1002/ep.670150119

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

摘要:

AbstractUsed automotive oil filter papers are typically contaminated with traces of lead and zinc particulates that may exceed the EPA toxicity characterization leaching procedure (TCLP) or the California soluble threshold limit concentration (STLC). The leachable lead and zinc content of oil filter paper may be reduced below hazardous waste levels by treatment with leach solutions comprised of metal complexing agents that dissolve a portion of the heavy metals. Further reduction of leachable lead and zinc in filter paper may be achieved by treatment with phosphate solutions to form insoluble metal phosphates. The resultant non‐toxic paper may be safely incinerated, while the leach “solubilizing” and phosphate “fixing” solutions are recycled. Lead and zinc are recovered from leach solutions by precipitation with sodium sulfide or polysulfide for beneficial use in lead/zinc smelter feedstock. The total levelized cost of treatment of filter paper to yield a non‐hazardous waste may range from $ 100–$ 300 p

ISSN:0278-4491    

DOI:10.1002/ep.670150120

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670150101

出版商:American Institute of Chemical Engineers    

年代:1996

数据来源: WILEY