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to Table of Contents As previously described, CenCITT's approach to clean reaction technology development involves 1) a study of material flows to identify waste reduction opportunities, 2) correlation of these opportunities to areas of fundamental expertise (e.g. bio- and heterogeneous catalysis) and resources/partners, 3) integration of fundamental expertise and efforts with process technology expertise, and 4) testing and implementation in collaboration with industry. Progress was made in each of these areas.
Under funding primarily from the EPA National Risk Management Research Laboratory, a project generated a limited-test prototype software tool for ranking industrial reaction pathways through the chemical industry by cost, toxic release and chemical risk. This tool, the Chemical Industry Planning System, contains information on the 240 chemicals and 310 process technologies that compose the hydrocarbon process industry (See Project Description).
Another project begun this past year seeks to characterize waste reduction opportunities in areas involving novel reaction/separation configurations for the production of chemicals and biodegradable plastics, efficient optimization and control strategies, and new solvents which prevent pollution. The project will involve a coordinated and comprehensive attack establishing a scientific basis and developing engineering approaches for eliminating processes which produce unwanted and difficult to capture by-products (See Project Description).
The overall goal of a project in microbial catalysis is to develop environmentally friendly processes for the production of chemicals from renewable feedstocks (See Project Description) . The test chemicals for the project are 1, 2- and 1,3-Propanediol (PD). 1, 3-PD is currently a relatively small volume specialty chemical, but was recently described as a potential "blockbuster", with large volume applications in polymers used in carpet fibers and other products (C& EN, July 17, 1995, p. 11). 1,2-PD is currently a large volume commodity chemical, with over 950 million pounds produced in the U.S. in 1994 and a 13% annual growth (C&EN, June 26, 1995, p. 40). 1,2-PD is used in unsaturated polyester resins, human and animal foods and as a non-toxic replacement for ethylene glycol in automobile antifreeze and airplane wing deicing fluids. Building upon previous patent-pending work, this year's efforts resulted in the purification of an enzyme which provides a means to decouple metabolic reactions involved in growth from reactions involved in energy production. This result opens the way to greatly increase the efficiency of metabolically produced diols.
Work in heterogeneous catalysis continues to yield good results. One project which focusses on the effects of adding modifiers and promoters to supported platinum catalysts used for selective conversion of isobutane to isobutene resulted in the determination of the rate limiting step in the process (See Project Description) . In virtually any reaction research, this determination is fundamental as it is the prime target of opportunity for which new reaction control strategies can be developed. This detemination led to invention of new highly-selective dehydrogenation catalysts which can replace a presently inefficient and dirty isobutane-to-isobutene reaction used in the production of methyl tert-butyl ether, a motor fuel oxygenate. Heterogeneous catalysis work now turns to the clean production of specialty fluorochemicals (See Project Description). These products comprise a $300 million per year business that is expected to grow at a rate of 10 to 15 percent per year. A joint project with the 3M Fluorochemical Technology Center will seek new, clean catalytic hydrogenation reactions which produce fluorochemicals without waste-generating chemical reducing agents, such as NaBH4.
An energy-efficient reactor for production of methanol from methane (natural gas) is being sought in a project which is just getting underway (See Project Description). Methane is both a clean fuel and a useful chemical feedstock. This innovative process technology project will develop a reactor in which both reaction and separation occur simultaneously. If successful, the Simulated Countercurrent Moving-Bed Chromatographic Reactor will have substantially lower energy requirements and be considerably more selective than previous methane to methanol processes which suffer from the difficulty of avoiding complete oxidation of methane to carbon dioxide and water. Tests of the new reactor should begin in early 1996.
A project was begun to test a photocatalysis process for the treatment and recirculation of industrial wastewater and the remediation of contaminated anaerobic water matrices (See Project Description) . The ability of a photocatalysis process to reclaim rinse water from computer chip manufacturing is being tested in the laboratory using wastewater obtained from Texas Instruments, Inc. A field demonstration is proposed which involves a semi-closed loop water recirculation system with the photocatalysis technology being used for final polishing of a secondary rinse water prior to reuse. If the process proves out, millions of gallons of water per day could be recycled.
As previously mentioned, the goal of CPAS is to help process and product designers devise, simulate and compare innovative design options. Considerations in these comparisons include cost, safety, health, environmental risk, emissions, use of recycled feed stocks, disassembly potential, constructability, and lifetime waste generation for process equipment, technologies and products. Progress toward a first release of CPAS continued at a fast pace this past year (See Project Description). CenCITT-developed tools slated for release in early 1996 include Adsorption Simulation and Aeration Systems Analysis Program , the Design Options Ranking Tool (DORT), and Software to Estimate Physical Properties (StEPP). The Process Safety and Risk Evaluation Tool (See Project Description) and Chemical Industry Planning System (See Project Description) are expected to follow these tools with release by mid-1996. By the end of 1996, the Fate of Volatile Organic Chemicals in WasteWater Treatment Plants (FaVOr), Fate of Metals in Waste Water Treatement Plants (FaMe), Reactive Chemistry Screening Tool (See Project Description), the Environmentally Conscious Constructability Tool (See Project Description) and the Environmental Fate and Risk Assessment (EFRAT) tools are forecasted to be released. In addition to these tools, the CPAS co-developers, CWRT and NCMS, are planning to contribute the Separation Technologies Database, Materials Compatibility Tool and a Solvent Properties Database.
During the past year, a plan was developed for release of the tools. The plan called for an administrative stewarding organization to be named to handle tool releases, operate a help line for user support, and handle tool fee collection and distribution. CenCITT was named to be the initial CPAS Administrative Steward. As first activities in this capacity, demonstration versions of ten CPAS tools were produced and have been distributed to over 500 companies and individuals. A prototype user routing interface for the overall system was developed (See Project Description). CPAS was presented at four national technical conferences and was the subject of two CenCITT-sponsored specialty conferences. Work is ongoing to identify other individuals and organizations who own or are developing software which could be made available through CPAS.
DORT activities saw an equipment costing database substantially completed, a prototype Economic Evaluation Aide developed and work initiated on graphical comparison and incremental analysis features (See Project Description). A stochastic model has been prepared and applied to a discounted cash flow routine. An Advanced Hierarchical Procedure (AHP) decision making test version has been programmed in Quick-Basic. This model picks the optimum of up to five design options based on user-supplied criteria, process economics, safety, and pollution generation.
Environmental Treatment Design Options Tools which have neared completion during the past year include gas- and liquid-phase versions of Adsorption Simulation Software, an ASAP version including surface, bubble, and counter-current packed tower aeration techniques, StEPP, FaVOr and FaMe (See Project Descriptions 1 and 2 ). In addition, a test version of Multi-Component Distillation (MC-Dist) has been created and distributed to the MTU senior Chemical Engineering plant design class for use in their coursework (See Project Description).
Building on StEPP, work began on scoping a general Physical Property Management System (PPMS), with an initial release forecast for December 1996 (See Project Description) . Other work in physical properties is developing molecular fraction-based models for sorption and vapor-liquid equilibrium modeling (See Project Description) .
A chemical-based tool to evaluate hazards associated with fires and explosions and utilizing the Dow Fire and Explosion Index has been essentially completed as a stand-alone prototype. A similar tool based on the Dow Chemical Exposure Index was begun near the end of FY1995 (See Project Description).
Many chemical plant accidents result from previously unknown reactive behavior of chemicals or incompatibilities between various chemicals. With any design or design change, an evaluation of the reactive chemistry of the process flowsheet is therefore critically important. Preliminary work began on a tool to evaluate hazards associated with reactive chemistry. It will be used to help insure that design decisions, including those intended to prevent pollution, do not result in hazardous reactive chemistry situations occurring (See Project Description).
The Environmentally Conscious Constructability Tool is scoped as a multimedia system for designers to infuse environmental concerns into the design process for constructed facilities, while simultaneously evaluating other facility performance criteria. This system will also serve as a resource database for manufacturers desiring to better understand field problems associated with installing their products. In conjunction with a proprietary in-house project of the M.W. Kellogg Company, a prototype has been developed and made ready for demonstration. The public-releasable version is slated for completion in 1996 and will contain text, images and video clips of hundreds of construction "lessons learned", including numerous environmentally preferable options (See Project Desription).
EFRAT is planned to be a process design software tool to estimate environmental and health impacts of chemical process design options through a combination of emission rate estimations, screening-level fate and transport calculations, risk assessment indices, and governmental regulatory guidance (See Project Descriptions 1 and 2 ). Within the past year, a multimedia compartment model approach has been selected from a number of options as a framework for estimating environmental persistence. Data sources for several risk indices have now been identified and work on the tool's user interface is well underway. A critical evaluation of EPA unit-specific emission factor databases and commercial emission estimation software has been completed and indicates very high variability and generally unreliable emission predictions.
A case study intended to experimentally develop a methodology for assessing pollution preventing process control schemes has proceeded well into its bench-scale equipment installation and testing phase (See Project Description). This bench-scale apparatus is paired with an existing pilot-scale batch reactor used for production of polydimethyl siloxane. The project's ultimate goal is to produce a pollution prevention methodology similar to HAZOP analysis. The stage is now set for waste minimizing control schemes to be experimentally evaluated and mathematically modeled.
This year witnessed completion of a program dealing with benificiation and reuse of combustion residuals. Projects within this program ranged from characterization of residuals to process control to in-process recycle to waste beneficiation for new commercial applications. Other projects, both new and ongoing, hold tremendous promise for new pollution preventing technologies in metal machining, plating, and finishing operations, as well as pulp mill and brass foundry by-product handling.
Beneficiation usually requires that the materials in question be characterized so that consistent quality can be achieved in the recycled material. For combustion processes, such characterization can often lead to insights into combustor operation, resulting in cleaner burns and production of less hazardous residual materials. One project sought an improved understanding of the behavior of lead in a municipal waste combustor (See Project Description). Results provide combustor designers with the fate, transport and thermodynamic aspects of lead within the combustor. This is fundamental information necessary to control the lead, and thereby produce ash residuals which are less toxic and more reusable. In this same project, a detailed study was made of the mechanisms responsible for the pozzalonic reactivity of coal furnace fly ash in portland cement concrete. The effort resulted in a recommendation for use of a selective phase dissolution procedure to determine fly ash reactivity. It is expected that this procedure could serve as the basis of a new reactivity-based fly ash classification system to replace the current ASTM procedure. Such an im provement in testing procedures could facilitate substantial growth in the ash reuse market.
Another characterization project sought the data required to optimize operating conditions for clean combustion of wood product wastes in fixed bed combustors, and photo finishing effluentin rotary kilns. From the data generated, means to control toxic material generation are now possible (See Project Description).
A project sought to demonstrate, by thermodynamic calculations and by bench-scale studies, that the combination of two waste products, pyrite coal-spoil and electric utility scrubber wastes (gypsum sludge), can result in a valuable products; namely, sponge iron and lime. In addition to the verification of a process reaction sequence, the project produced a novel magnetic method to separate iron-calcium sulfide mixtures, producing a magnetic concentrate lower in sulfur content. With further work to reduce sulfur content, this beneficiated material will be able to meet steelmaking standards (See Project Description).
In a project focussing on expanding the beneficial uses of coal fly ash, a technology was demonstrated to remove carbon, which is a troublesome contaminant preventing many fly-ashes from being utilized (See Project Description). The de-carbonized fly-ash was then shown to be suitable for formation of high-strength, light-weight sintered pellets. It also shows promise for use as a binder component for formation of pellets of other inorganic materials. This is a significant breakthrough, as iron-ore pellets produced with fly-ash-based binders have never before been produced which meet industrial dry-crush strength requirements. The end result of this project, then, is the production of a binding material from what would have otherwise been a waste, and the opportunity to make many sorts of inorganic fine particulate wastes reuseable. Waste + Waste = Product!
Another project has shown that an activated carbon derived from fly-ash is capable of adsorbing mercury from samples of coal fired boiler effluent. This project successfully demonstrated a new use (and potential market) for combustion waste, and at the same time, a method to detoxify boiler effluent. The fabrication of a fluidized bed for activation of the carbons is in progress (See Project Description).
A project focussed on developing a means to recover copper, zinc and lead from brass foundry waste for in-process recycle (See Project Description). It also dealt with separation of mercury from copper concentrates. The project resulted in a novel, low cost process to produce PbO (litharge and massicot) from virtually any lead source (waste or raw material). Current economic estimates of the process show that PbO could be made consistently for as low as $0.26 per pound. Given that the current cost of PbO fluctuates from $0.20/lb to $1.00/lb, significant savings are possible. The process is to be applied to the waste crucibles from gold mining operations which contain large amounts of lead. The wastes will be stripped of the lead, and the lead will be processed to recover litharge for reuse in the assay process. The mercury separation experiments lead to similar successes. Not only could 100% of the elemental mercury be recovered at temperatures of less than 400oC, but the cinnabar was broken down as well.
Following from initial success in the commercial use of a new, water-based ink by the Deluxe Corporation, a project was initiated to develop a scientific basis for the ink's action, and to expand this concept to design solvents for other industries (See Project Description). These new solvents will be non-volatile, and can be made soluble in water by varying process conditions, like pH or temperature. Moreover, these new solvents can be easily recycled.
In a project just getting underway, a basic technology is being developed to manufacture the first biodegradable plastics that are truly lignin-based (See Project Description). Existing methods achieve lignin contents of 25-40 percent in polymer blends. The approach under investigation in this CenCITT project can produce blends containing 85 percent underivatized industrial kraft lignin. The project is continuing to develop performance and strength testing for laboratory-produced blends. The significance of this project is two-fold: 1) a high volume, value-added bulk material could be created which replaces a fossulate raw material source with a renewable one, and 2) with some pulping industry forecasts predicting a potential for lignin production exceeding pulp mill combustor demands, successful results of this project would avoid potentially huge future landfill requirements.
Following from work performed over the past couple of years to develop engineering guidelines for design of hollow fiber membrane separation modules (See Project Descriptions 1 and 2 ), focus now turns to in-process recycle uses of the technology (See Project Description). Specially treated versions of these membranes are being tested for use in recovering oil from spent cutting fluids from metal machining operations. Current technology for treating these fluids involves use of acids and coagulants to crack emulsions and separate oil and water phases. This normally results in an oily sludge and a large volume of strongly acidic water, both of which require further treatment. Successful demonstration of a hollow fiber membrane separation technology will allow for in-process recycle of the cutting oil and avoidance of the current waste-generating waste treatment processes.
Another membrane technology demonstration project investigates its potential for use with adsorbents in an integrated ion exchange process known as continuous deionization (CDI). Specifically, this project is investigating the use of CDI to recover copper sulfate and purified water from acidic, copper-rich electroplating rinsewaters (See Project Description). This in-process recycle process would eliminate or greatly reduce the need for conventional, lime precipitation treatment which loses the metal content of the rinsewater and can generate large volumes of hydroxide sludge that is difficult to handle and costly to dispose.
The potential for major reductions in air emissions has made electrodeposition paint coating (E-Coat) technology a leading alternative to conventional solvent-borne spray painting for metal parts in manufacturing. Additional pollution prevention opportunities exist, however, especially with regard to wastewater and solid waste pollution problems. A project was initiated late in the year to assess the net environmental benefits of using E-Coat and to hone E-Coat operating practices based on targets of opportunity identified in this assessment (See Project Description).
Begun as an exploratory project two years ago, efforts in environmentally conscious manufacturing (ECM) have developed design-for-dissassembly guidelines which are now being used commercially. Moreover, the area has developed an automotive focus and expanded participation.
The initial ECM project set out to develop environmentally conscious design and manufacturing tools and methods with an intention to help alleviate the abundance of waste associated with used product and manufacturing waste streams (See Project Description). The project resulted in development of a Reprocessability Index which characterizes parts by their shape, features, volume and stress. It is a measure of how physical properties and orientations affect environmental impact. Another aspect of this project considered the role of cutting fluid in machining operations. It was found that the fluid was not a significant factor in the boring of aluminum alloys, but it is becoming evident that the fluid does have an effect in small diameter drilling. This finding is resulting in a recommendation for complete elimination of cutting fluids for some applications. That's pollution prevention! Other results of this wide-ranging project include the development of models to simulate the shredding of various plastics in automotive shredder residue, improvements in shredding methods, and a demonstration software tool to profile production waste costs for automobile bumper manufacturing.
A new project seeks to develop a design for disassembly methodology, including a numerical simulation capability, so that products, such as automobiles, may be disassembled and their components reutilized or recycled (See Project Description). Early results of this project have produced a version of the non-destructive disassembly technique for generic assemblies. It is currently being implemented on the computer and evaluated for industrial application.
Efforts in environmentally conscious construction, which are described above under Clean Process Design Guidelines, will likely integrate well with these ECM projects as they continue to progress (See Project Description).