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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Integrated Waste Feed Qualification Program for Direct LAW Feed to WTP - 16421

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is a one-of-a-kind facility being designed and constructed for DOE by Bechtel National, Inc. (BNI) and principal subcontractor URS, to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS), has the responsibility to retrieve, stage, pretreat, and deliver feed directly to the WTP Low Activity Waste (LAW) Vitrification Facility. The Direct Feed LAW (DFLAW) scenario is being considered by DOE as a strategy to treat Hanford tank wastes as soon as practicable. Extensive planning is underway by One System, an effort with joint participation by WTP and TOC personnel. The initial focus of One System is to achieve the required integration to ensure the waste feed meets acceptance requirements for processing in the TOC Low Activity Waste Pretreatment System (LAWPS) and WTP LAW facilities. The integrated waste feed qualification program approach for DFLAW was defined by One System during a four-day workshop. The effort resulted in a feasible approach for integrating LAWPS and LAW feed acceptance requirements to vitrify low-activity waste while complying with facility design basis, safety basis, waste acceptance criteria, and glass product compliance. The defined qualification program will provide a systematic approach to test newly staged feed campaigns at bench-scale using actual tank waste samples. The required integration and basis for obtaining sufficient and necessary data to qualify the feed for DFLAW facilities are discussed in this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Corrosion Evaluation for Tank 241-AP-106 Re-purposing

Tank AP-106 will be an integral part of the Direct Feed Low Activity Waste (DF-LAW) activity. This tank is an underground, carbon steel, double shell tank (DST). Before it can be utilized, the Cs-137 concentration levels in the waste must be reduced significantly. The AP-106 re-purposing process will manage normal waste tank additions procedures such that waste acceptance criteria objectives for Cs-137 removal are achieved. As this process was being developed, concerns regarding tank integrity during and after the process to Tank AP-106 and associated tanks (i.e., AP-102, AN-101, and AP-108) were addressed. The degradation mechanisms identified include: general and pitting corrosion, caustic stress corrosion cracking, galvanic corrosion, and microbiologically induced corrosion (MIC). Recommendations were provided to minimize the exposure of the tank to corrosive conditions (see Section 6.0). These recommendations included chemistry adjustments at defined steps in the process that will maintain the waste in compliance with the corrosion control program. Additionally, sampling and inspection (see Sections 6.0 and 7.0, respectively) recommendations that will assess the final condition of the tank environment and the tank were presented. The greatest risk for this process involves the handling of large quantities of Columbia River water (i.e., greater than 450,000 gallons) within the AP-106, associated tanks and supporting infrastructure (i.e., transfer line piping). As long as this water is blended into the supernate in a timely fashion, and the waste is adjusted appropriately with corrosion inhibitors, the final condition is expected to be within compliance. Recommendations were also made to address process interruptions that could result in exposure of the tank walls to aggressive conditions.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Integrated Readiness Activities for the Direct Feed Low Activity Waste (DFLAW) Program - 16221

The WTP is a one-of-a-kind nuclear waste treatment facility being designed and constructed for the DOE by Bechtel National, Inc. (BNI) and principal subcontractor URS-AECOM, to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS), has the responsibility to retrieve, stage, pretreat, and deliver the pretreated feed directly to the WTP Low-Activity Waste Vitrification Facility, scope referred to as Direct Feed Low Activity Waste (DFLAW). Extensive planning is in progress under the auspices of One System, an effort with joint participation by WTP and TOC personnel. To support an integrated approach to readiness for the DFLAW Program, an Integrated Operational Readiness Committee (IORC) was established to contribute to a safe and effective operational readiness of the WTP. The IORC, an advisory committee, comprising representatives from BNI, WRPS, and the Hanford interfacing partners for WTP operations, Mission Support Alliance (MSA) and CH2M HILL Plateau Remediation Company (CHPRC). In addition, an Operational Readiness (OR) workshop was conducted with several objectives accomplished to support an integrated approach to readiness with specific focus on the management of interfaces between the various contractors and facilities. This culminated in the development of a readiness strategy document called the Operational Readiness Support Plan (ORSP). This ORSP describes the joint approach to WTP startup operating in the DFLAW configuration. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Alternative High-Performance Ceramic Waste Forms

This final report (M5NU-12-NY-AU # 0202-0410) summarizes the results of the project titled “Alternative High-Performance Ceramic Waste Forms,” funded in FY12 by the Nuclear Energy University Program (NEUP Project # 12-3809) being led by Alfred University in collaboration with Savannah River National Laboratory (SRNL). The overall focus of the project is to advance fundamental understanding of crystalline ceramic waste forms and to demonstrate their viability as alternative waste forms to borosilicate glasses. We processed single- and multiphase hollandite waste forms based on simulated waste streams compositions provided by SRNL based on the advanced fuel cycle initiative (AFCI) aqueous separation process developed in the Fuel Cycle Research and Development (FCR&D). For multiphase simulated waste forms, oxide and carbonate precursors were mixed together via ball milling with deionized water using zirconia media in a polyethylene jar for 2 h. The slurry was dried overnight and then separated from the media. The blended powders were then subjected to melting or spark plasma sintering (SPS) processes. Microstructural evolution and phase assemblages of these samples were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion analysis of x-rays (EDAX), wavelength dispersive spectrometry (WDS), transmission electron spectroscopy (TEM), selective area x-ray diffraction (SAXD), and electron backscatter diffraction (EBSD). These results showed that the processing methods have significant effect on the microstructure and thus the performance of these waste forms. The Ce substitution into zirconolite and pyrochlore materials was investigated using a combination of experimental (in situ XRD and x-ray absorption near edge structure (XANES)) and modeling techniques to study these single phases independently. In zirconolite materials, a transition from the 2M to the 4M polymorph was observed with increasing Ce content. The resulting powders were consolidated via SPS. Ce was reduced to the trivalent oxidation state and the zirconolite was converted into undesirable perovskite. The zirconolite polymorphs found in the synthesized powders were recovered after a post-SPS heat treatment in air. These results demonstrated the potential of processing in controlling the phase assemblage in these waste forms. Hollandites with Cr 3+ trivalent cations were identified as potential hosts for Cs immobilization and are being investigated for Cs retention properties. Series of compositions Ba 1.15-x Cs 2x Cr 2.3 Ti 5.7 O 16 , with increasing Cs loadings, were prepared by sol-gel process and characterized for structural parameters. Structural characterization was performed by a combination of powder XRD and neutron powder diffraction. Phase pure hollandite adapting monoclinic symmetry (I2/m) was observed for 0 ≤ x ≤ 0.55. These results were used to develop a new structural model to interpret Cs immobilization in these hollandites. Performance of these waste forms were evaluated for chemical durability and radiation resistance. Product consistency testing (PCT) and vapor hydration testing (VHT) were used for testing of chemical durability. Radiation resistance was tested using He + ions to simulate $\alpha$ particles and heavy ions such as Au 3+ to simulate a recoil. These results showed that these waste forms were chemically durable. The waste forms also amorphized to various degrees on exposure to simulated radiation.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Chemical Reactivity and Recommended Remediation Strategy for Los Alamos Remediated Nitrate Salt (RNS) Wastes

Nitrate salt wastes were generated during historical processing operations to recover and purify plutonium at Los Alamos National Laboratory (LANL). These nitrate salts have the potential to behave as oxidizers, and to contain entrained liquids, both of which are prohibited in the Waste Isolation Pilot Plant (WIPP). A process was developed to remediate nitrate salts by mixing salts with an inorganic zeolite pet litter to absorb free liquids, and remove the oxidizing characteristic of the wastes. Process changes introduced instead an organic wheat-­-based pet litter along with organic neutralizers, generating a new waste form referred to as Remediated Nitrate Salt (RNS) waste. The February 2014 radiological release at the WIPP site was traced to a LANL RNS waste drum number 68660. Experimental and modeling studies performed at LANL indicate that mixtures of metal nitrate salts (oxidizer) with Swheat organic kitty litter (fuel) create the potential for exothermic chemical reactions. Even in the presence of triethanol-­-ammonium nitrate (TEAN) created during neutralization, relatively high temperatures, greater than approximately 160 °C (320 °F), are required for runaway exothermic reactions. Evaluation of Drum 68660 characteristics coupled with extensive chemical testing indicate that, in addition to the nitrate salt/Swheat organic kitty litter mixture, an additional trigger mechanism (or mechanisms) is likely required to raise the internal drum temperature high enough to initiate the nitrate salt/Swheat organic kitty litter reaction. A combination of chemical conditions were identified that may lower the temperature for reaction, including initial high acid concentration of free liquids; significant quantities (> 1 gal) of neutralized, absorbed free liquids; the presence of reactive or catalytic metals like magnesium, iron, or lead; the presence of bismuth containing glovebox gloves; and the presence of natural biological activity. Complex surrogate nitrate salt mixtures prepared to simulate wastes, particularly those containing iron and magnesium, can generate NOx gases that partially nitrate the organic Swheat kitty litter and form a more energetic fuel. These complex surrogate salt mixtures display exothermic behavior at temperatures as low as 60 °C (140 °F) which is still well above the ambient temperature conditions experience by a drum. Neutralization of free liquids, and sorption onto Swheat establishes conditions (moisture) with near-neutral pH) that will support natural biological activity. Spontaneous self-heating generated by low-level chemical reactions and/or the respiration of bacteria, molds, and microorganisms is potentially important in the early stages and may be sufficient to raise the temperature as high as 60 °C (140 °F), where the other exothermic chemical reactions can take place. Additional studies are being conducted to evaluate the role biological activity may have played in initiating the event. The use of Swheat absorbent in the processing of nitrate salt wastes can be pinpointed as the critical processing decision that led to the failure of drum 68660, regardless of the ii details of the thermal processes that enabled the drum to achieve temperatures sufficient to initiate the chemical reactions.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Measurement of Iodine, Iodide, and Iodate in Hanford Tank Waste: Technology Transfer from PNNL to Hanford 222-S Laboratory

This report summarizes the measurement of the inorganic chemical forms of iodine in Hanford tank waste. The Hanford tank wastes have roughly a part per million iodine. Part of the iodine is the long-lived beta emitter 129I, and the rest is stable 127I. Because tank waste iodine is radioactive and radiotoxic, its chemical form must be known so that its behavior in the vitrification process can be reliably known and anticipated in various waste streams (glass, secondary liquid and solid waste, and offgas emissions) at Hanford. Iodine in tank wastes exists in the inorganic chemical forms iodide and iodate (and possibly also periodate) and also as organic forms such as alkyl iodides. The measurement of organic iodides is very different from the measurement of inorganic forms and is outside the scope of this report. The inorganic chemical forms are chemically separated, in sequence, from the raw tank waste using solvent extractions and several redox reactions, then measured by ICP-MS. The inorganic chemical forms of iodine are chemically reactive, and so is the tank waste. The chemistry must be carefully designed to avoid unintended reactions that could convert one form of iodine to another during the analysis, which would skew the data and report iodine in the wrong chemical form. This iodine analysis, developed at PNNL, is being transferred to the DOE 222-S Laboratory on the Hanford Site, in Washington State, for implementation during waste processing operations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Arvia organics destruction: an innovative treatment approach for dioxins, furans and other problematic (Orphan) organic wastes - 15380

The safe and efficient disposal of radionuclide-contaminated organic wastes is a key component in the life-cycle of a nuclear power plant. Technologies are available for the processing of some of these wastes although there are a number of waste streams for which the disposition path is not clear or does not exist at all. For example, waste streams such as dioxin, furan and PCB-laden oils pose an issue for the US Dept. of Energy complex. These wastes present a challenge as they cannot be readily treated using existing treatment technologies because of legislative and material constraints such as gaseous phase radioactivity discharge limits, waste elemental content, by-product generation and waste resistance to thermal decomposition. Alternate methods of organics destruction can circumvent some of these issues by using different mechanisms of organics oxidation. One such innovative method, known as the Arvia organics destruction process, combines adsorption with electrochemical combustion and offers such an alternative. This technology, based on a patented material, Nyex{sup TM} that is able to act as both an adsorbent and as an electrode, allows the electrochemical combustion of adsorbed organics to occur on the material's surface. The result is the destruction of organics whilst the bulk of inorganic and radionuclide components remain in the aqueous phase. These components can subsequently be treated using existing waste processing technologies. This paper outlines recent work conducted on demonstrating the Arvia process against the destruction of dioxin, furan and PCB-laden wastes that demonstrates that the technology successfully removes these target species to below discharge standards in the aqueous phase. Based on these successful trials a test unit has been designed to demonstrate the process on actual radioactive wastes at the DOE Oak Ridge facility. The successful treatment of F027-coded waste has also been demonstrated and will be reported. The above work showcases the development, scaling and application of an innovative technology, first presented to the industry at the Waste Management Symposia in 2012, as another option for the treatment of challenging wastes with expensive, complex or no current disposal routes. The Arvia process adds to the portfolio of available treatment technologies and will help facilitate the decommissioning and waste disposal responsibilities of the nuclear industry. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Modularized Production of Fuels and other Value-Added Products from Distributed, Wasted, or Stranded Feedstocks

Distributed, wasted, or stranded feedstocks, when converted and upgraded into fuels, could replace about 6% of the US demand for liquid fuels, which is about 25% of the net import of petroleum by the US. We review the current state of modular approaches for conversion of these feedstocks, including the technology and economics associated with processing carbon-containing waste and stranded, carbon-containing gas. The wide geographic distribution of the feedstocks will require technology that can be scaled down effectively and that can be manufactured, installed, operated and monitored in ways that gain economies of mass production rather than economies of throughput scaling.

Weber, Robert S.↗
DOE OSTI2021

Maximum Cs-137 Curie Loading onto Crystalline Silicotitanate for the Documented Safety Analysis of the Tank Side Cesium Removal Platform

The Tank Side Cesium Removal (TSCR) system is currently being constructed to process Hanford tank waste supernates for vitrification. TSCR incorporates a filtration system and cesium (Cs) removal system using columns filled with crystalline silicotitanate (CST) ion exchanger, produced by Honeywell UOP, LLC. The documented safety analysis (DSA) developed for TSCR limits a single column curie loading to 141,600 Ci; given a 137 Cs isotopic mass fraction of 20% and the planned CST bed size of a TSCR column, this equates to 0.10 mmole Cs per g CST. Factors that influence 137Cs loading onto the CST include, but are not limited to, CST production lot (different production lots behave differently), contact temperature, contact duration, 137Cs mass fraction, and competitors in the tank waste feed. Seventeen tank waste feeds (compositions) were identified by Washington River Protection Solutions to be processed through TSCR. These feed compositions were used to develop a simulant (referred to herein as Stage 1) that would provide an upper bound to the Cs loading onto CST based on maximizing the Cs/Na activity coefficient ratios in solution while maintaining Na at no less than 5.0 M. Building upon this Stage 1 simulant, a series of four additional simulants were developed based on the cationic/anionic species that impact Cs exchange, with each successive formulation relaxing one or more matrix component concentration constraints as show in Table S.1

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Full-scale composting of sewage sludge and market waste: Stability monitoring and odor dispersion modeling

Highlights: • Composting process of different organic waste was monitored at full-scale. • Relationships among odor emissions and analytical and biological variables were found. • Removal of nitrogen and volatile solids was the main responsible for odor generation. • Biomethanization pretreatment reduced odor impact at the beginning of composting. • The highest odor immission occurred in summer season for a wind speed of 2.6 m/s. The aim of this study was to assess the odor immission derived from full-scale composting of different abundant and highly pollutant organic waste: sewage sludge with bulking agent (SL), sewage sludge pretreated through anaerobic digestion and supplemented with bulking agent (SL-AD), and market waste with olive leaves (MW-OL). The combination of dynamic olfactometry and Gaussian dispersion modeling allowed both the quantification of odor emissions from each waste and the evaluation of their global odorous impact in nearby urban areas. Wind speed, summer and winter seasons, and atmospheric conditions were considered in the dispersion model. The results revealed that high wind speed (2.6 m/s) increases the global odor immission in summer season, independently of atmospheric stability. However, the maximum odor immission concentration recommended for composting process was not exceeded in any case, which depends on each country/region. The experimental results also enable to evaluate the influence of several physico-chemical variables on odor emissions derived from composting. The removal of nitrogen and volatile solids was the main cause for odor generation. Moreover, the microbiological activity of each substrate was monitored throughout the process and different percentages of biodegradability were quantified depending on the type of substrate and pretreatment applied.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Crystallization In High Level Waste (HLW) Glass Melters: Operational Experience From The Savannah River Site

processing strategy for the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal tolerant high level waste (HLW) glasses targeting higher waste loadings while still meeting process related limits and melter lifetime expectancies. This report provides a review of the scaled melter testing that was completed in support of the Defense Waste Processing Facility (DWPF) melter. Testing with scaled melters provided the data to define the DWPF operating limits to avoid bulk (volume) crystallization in the un-agitated DWPF melter and provided the data to distinguish between spinels generated by K-3 refractory corrosion versus spinels that precipitated from the HLW glass melt pool. This report includes a review of the crystallization observed with the scaled melters and the full scale DWPF melters (DWPF Melter 1 and DWPF Melter 2). Examples of actual DWPF melter attainment with Melter 2 are given. The intent is to provide an overview of lessons learned, including some example data, that can be used to advance the development and implementation of an empirical model and operating limit for crystal accumulation for WTP. Operation of the first and second (current) DWPF melters has demonstrated that the strategy of using a liquidus temperature predictive model combined with a 100 °C offset from the normal melter operating temperature of 1150 °C (i.e., the predicted liquidus temperature (TL) of the glass must be 1050 °C or less) has been successful in preventing any detrimental accumulation of spinel in the DWPF melt pool, and spinel has not been observed in any of the pour stream glass samples. Spinel was observed at the bottom of DWPF Melter 1 as a result of K-3 refractory corrosion. Issues have occurred with accumulation of spinel in the pour spout during periods of operation at higher waste loadings. Given that both DWPF melters were or have been in operation for greater than 8 years, the service life of the melters has far exceeded design expectations. It is possible that the DWPF liquidus temperature approach is conservative, in that it may be possible to successfully operate the melter with a small degree of allowable crystallization in the glass. This could be a viable approach to increasing waste loading in the glass assuming that the crystals are suspended in the melt and swept out through the riser and pour spout. Additional study is needed, and development work for WTP might be leveraged to support a different operating limit for the DWPF. Several recommendations are made regarding considerations that need to be included as part of the WTP crystal tolerant strategy based on the DWPF development work and operational data reviewed here. These include: Identify and consider the impacts of potential heat sinks in the WTP melter and glass pouring system; Consider the contributions of refractory corrosion products, which may serve to nucleate additional crystals leading to further accumulation; Consider volatilization of components from the melt (e.g., boron, alkali, halides, etc.) and determine their impacts on glass crystallization behavior; Evaluate the impacts of glass REDuction/OXidation (REDOX) conditions and the distribution of temperature within the WTP melt pool and melter pour chamber on crystal accumulation rate; Consider the impact of precipitated crystals on glass viscosity; Consider the impact of an accumulated crystalline layer on thermal convection currents and bubbler effectiveness within the melt pool; Evaluate the impact of spinel accumulation on Joule heating of the WTP melt pool; and Include noble metals in glass melt experiments because of their potential to act as nucleation sites for spinel crystallization.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

Highlights: Black-Right-Pointing-Pointer Simultaneous measurements of 23 elements in process gases of a waste wood combustor. Black-Right-Pointing-Pointer Mobile ICP spectrometer allows measurements of high quality at industrial plants. Black-Right-Pointing-Pointer Continuous online measurements with high temporal resolution. Black-Right-Pointing-Pointer Linear correlations among element concentrations in the raw flue gas were detected. Black-Right-Pointing-Pointer Novel sampling and calibration methods for ICP-OES analysis of process gases. - Abstract: A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. The analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Innovative Approach to the Management of Waste Arising from the Decommissioning of a Redundant Plutonium Processing Facility - 17081

There are a number of redundant plutonium processing facilities located at Sellafield, in the North West of England within the United Kingdom (UK). Over past decades several decommissioning strategies have been deployed to clean up these redundant facilities. Whilst there have been many successes previously reported, there remain many challenges. Some of these challenges have recently been addressed through a new approach which introduces a number of innovations. The new approach seeks to significantly reduce risks to both decommissioning personnel and the environment by minimising the extent of physical 'hands on' decommissioning activities and by simplifying the waste production process. A large bagless transfer system has been engineered to allow the transfer of whole gloveboxes into crates. This leads to a significant reduction in hazardous 'hands on' work in a highly contaminated environment. The crates are consigned directly to interim storage on the Sellafield site. These hazard minimisation activities have only been made possible through the development and implementation of a new approach to criticality safety assessment. This new approach has recently completed active commissioning with the first waste being safely exported in June 2016. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Hydrocoals from waste biomass via catalytic hydrothermal carbonization processing

This study investigates how operating conditions (temperature and residence time) and benzoyl chloride impact hydrochar production from almond shells through hydrothermal carbonization. Carbon content rises while volatile matter decreases with increasing temperature, yielding a hydrochar with an estimated heating value of 28 MJ/kg. Elevated temperatures lower the O/C and H/C atomic ratios of hydrochars. Even at the lowest temperature under scrutiny, catalytic experiments using benzoyl chloride enhance carbonization and fuel ratio across all temperatures. Hydrochars produced through catalytic runs demonstrate elevated fuel ratios relative to those generated through noncatalytic runs, despite operating under the same conditions. These insights reveal the capacity of benzoyl chloride as a catalyst to improve hydrochar properties, suggesting its utility for advancing both the efficiency and effectiveness of hydrothermal carbonization processes.

09 BIOMASS FUELS↗
DOE OSTI2025

Renewable diesel and bio-aromatics production from waste cooking oil using ethanol as a hydrogen donor in deoxygenation reaction

Biofuels offer a promising solution in the fight against climate change. With a global increase in waste cooking oil, this research investigated the production of bio-hydrogenated diesel (BHD) from waste cooking oil, using ethanol as a hydrogen donor in the deoxygenation process. A hydrolyzed waste cooking oil model compound served as the feedstock, and the deoxygenation was performed at 300–400 °C. The catalysts used in the experiments were 2.6 wt% Ni and 7.8 wt% Mo (2.6Ni-7.8Mo) and 10 wt% Ni and 5 wt% Mo (10Ni-5Mo) on γ-Al 2 O 3 . The results showed that ethanol is an effective hydrogen donor for biofuel production without the need for external hydrogen at an elevated pressure. The increasing temperature enhanced the free fatty acid (FFA) conversion and n-alkane selectivity in the oil product, with the highest FFA conversion and alkane selectivity of 100 % and 46 %, respectively, observed at 400 °C for the sulfided 10Ni-5Mo catalyst. On the other hand, 2.6Ni-7.8Mo offers 100 % FFA conversion with a lower n-alkane selectivity of 35 % at identical temperatures. The total acid number (TAN) of the oil products decreased from 174.03 mg KOH/g of feedstock to 9.43 and 8.67 mg KOH/g with the sulfided 2.6Ni-7.8Mo and 10Ni-5Mo catalysts, respectively. Both the catalysts achieved similar heating values (~43 MJ/kg) at 400 °C. This is a significant improvement to the HHV of the feedstock, which was 36.02 MJ/kg. Additionally, aromatic compounds, mainly BTXE (benzene, toluene, xylene, and ethylbenzene), were also produced. Compared to glycerol as a hydrogen donor, ethanol more effectively increased n-alkane selectivity due to its higher effective hydrogen-to-carbon ratio (H/C eff ). Conversely, glycerol was more advantageous for achieving greater selectivity towards BTXE compounds due to its lower H/C eff , which potentially leads to coke formation. Since aromatic compounds are intermediates in coke production, glycerol provides higher aromatic selectivity than ethanol. Finally, this study presents an alternative pathway for producing diesel fuel from waste cooking oil using ethanol as a hydrogen donor.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Comparing the greenhouse gas emissions from three alternative waste combustion concepts

Highlights: Black-Right-Pointing-Pointer Significant GHG reductions are possible by efficient WtE technologies. Black-Right-Pointing-Pointer CHP and high power-to-heat ratio provide significant GHG savings. Black-Right-Pointing-Pointer N{sub 2}O and coal mine type are important in LCA GHG emissions of FBC co-combustion. Black-Right-Pointing-Pointer Substituting coal and fuel oil by waste is beneficial in electricity and heat production. Black-Right-Pointing-Pointer Substituting natural gas by waste may not be reasonable in CHP generation. - Abstract: Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system. The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO{sub 2}-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not achieved.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2012

The environmental comparison of landfilling vs. incineration of MSW accounting for waste diversion

Highlights: Black-Right-Pointing-Pointer Residential waste diversion initiatives are more successful with organic waste. Black-Right-Pointing-Pointer Using a incineration to manage part of the waste is better environmentally. Black-Right-Pointing-Pointer Incineration leads to more power plant emission offsets. Black-Right-Pointing-Pointer Landfilling all of the waste would be preferred financially. - Abstract: This study evaluates the environmental performance and discounted costs of the incineration and landfilling of municipal solid waste that is ready for the final disposal while accounting for existing waste diversion initiatives, using the life cycle assessment (LCA) methodology. Parameters such as changing waste generation quantities, diversion rates and waste composition were also considered. Two scenarios were assessed in this study on how to treat the waste that remains after diversion. The first scenario is the status quo, where the entire residual waste was landfilled whereas in the second scenario approximately 50% of the residual waste was incinerated while the remainder is landfilled. Electricity was produced in each scenario. Data from the City of Toronto was used to undertake this study. Results showed that the waste diversion initiatives were more effective in reducing the organic portion of the waste, in turn, reducing the net electricity production of the landfill while increasing the net electricity production of the incinerator. Therefore, the scenario that incorporated incineration performed better environmentally and contributed overall to a significant reduction in greenhouse gas emissions because of the displacement of power plant emissions; however, at a noticeably higher cost. Although landfilling proves to be the better financial option, it is for the shorter term. The landfill option would require the need of a replacement landfill much sooner. The financial and environmental effects of this expenditure have yet to be considered.

09 BIOMASS FUELS↗