Model compound testing was conducted in a batch reactor to evaluate the effects of trace contaminant components on catalytic hydrogenation of sugars. Trace components are potential catalyst poisons when processing biomass feedstocks to value-added chemical products. Trace components include inorganic elements such as alkali metals and alkaline earths, phosphorus, sulfur, aluminum, silicon, chloride, or transition metals. Protein components in biomass feedstocks can lead to formation of peptide fractions (from hydro-lysis) or ammonium ions (from more severe breakdown), both of which might interfere with catalysis. The batch reactor tests were performed in a 300-mL stirred autoclave, with multiple liquid samples withdrawn over the period of the experiment. Evaluation of these test results suggests that most of the catalyst inhibition is related to nitrogen-containing components.

This annual report gives the results of the work conducted by the Pacific Northwest Laboratory in FY 1994 on Task 3 of the Ferrocyanide Safety Project, Ferrocyanide Aging Studies. Waste aging refers to the dissolution and hydrolysis of simulated Hanford ferrocyanide waste in alkaline aqueous solutions by radiolytic and chemical means. The ferrocyanide simulant primarily used in these studies Savannah River Operations Office PO. Box A

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SummaryThis annual report gives the results of the work conducted by the Pacific Northwest Laboratory in FY 1995 on Task 3 of the Ferrocyanide Safety Project, Ferrocyanide Aging Studies. Aging refers to the dissolution and hydrolysis of simulated Hanford ferrocyanide waste in alkaline aqueous solutions by radiolytic and chemical means. The ferrocyanide simulant primarily used in these studies was driedIn-Farm-lB, Rev. 7, prepared by Westinghouse Hanford Company to simulate the waste generated when the In-Farm flowsheet was used to remove radiocesium from waste supernates in single-shell tanks at the Hanford Site. In the In-Farm flowsheet, nickel ion A d ferrocyanide anion were added to waste supernates to precipitate sodium nickel ferrocyanide, Na,NiFe(CN),, and co-precipitate radiocesium. Once the radiocesium was removed, supernates were pumped from the tanks, and new wastes from cladding removal processes or from evaporators were added. These new wastes were typically highly caustic, having hydroxide ion concentrations of over 1 M and as high as 4 M. The Aging Studies task is investigating reactions this caustic waste may have had with the precipitated ferrocyanide waste in a radiation field.In previous Aging Studies research, N%NiFe(CN), in simulants was shown to dissolve in basic solutions, forming insoluble Ni(OH), and soluble Na,Fe(CN),. The influence on solubility of base strength, sodium ion concentration, anions, -and temperature was previously investigated. Destruction of ferrocyanide anion by hydrolysis to form ammonia and formate ion was found to be promoted by gamma irradiation. Increasing temperature and gamma dose rate increased the rate of hydrolysis, as indicated by the amount of ammonia formed with time. Ammonia was found to be radiolyzed in the gamma field. The change in concentration of formate ion generally paralleled that of ammonia but was three to four times less concentrated. Total soluble iron concentrations were found to decrease in what appeared to be a pseudo-first-order fashion. The nickel concentration tended to increase, sometimes to 90% redissolution. Aluminum added to the hydrolysis solution had relatively little effect and may have slightly promoted hydrolysis.. In FY 1995 Aging Studies work, temperature and gamma dose rate effects were further investigated. Consistent with prior work, as the temperature or the gamma dose rate increased, the rate of hydrolysis also increased. As an approximation, ammonia production with time was described as being linear. Rate constants for ammonia production followed a linear Arrhenius relationship and also increased linearly with increasing applied gamma dose rate. Rate constants for ammonia production at other conditions could be predicted with use of the temperature and dose rate relationships.Ammonia was found to be destroyed in the gamma environment. Rate constants of 1.1 x Mlday at an applied dose rate of 1.07 x l@ Rad/h, and 2.1 x lo4 Mlday at 8.91 x 103 Rad/h were measured for this process. Formate ion destruction was found to occur at...

SummaryThis final report gives the results of the work conducted by Pacific Northwest National Laboratory (PNNL) from FY 1992 to FY 1996 on the Ferrocyanide Aging Studies, part of the Ferrocyanide Safety Project. The Ferrocyanide Safety Project was initiated as a result of concern raised about the safe storage of ferrocyanide waste intermixed with oxidants, such as nitrate and nitrite salts, in Hanford Site single-shell tanks (SSTs). In Numerous studies conducted by the Task Team defmed safety criteria and resulted in closure of the USQ in March 1994. The potential for ferrocyanide reactions in Hanford Site SSTs was evaluated, and the energy released during these reactions was quantified. Dynamic X-ray diffraction was also used to identify specific reactions and to quantify reaction rates. In addition, a number of experimental and theoretical studies were conducted in an effort to analyze the thermal characteristics of the tanks and to investigate the likelihood of "hot spots" forming as a result of radiolytic heating.Resolving the Ferrocyanide Safety Issue requires that tank contents meet the safety criteria and operations be conducted such that waste conditions fall within the criteria limits. Because the ferrocyanide sludge has been exposed for many years to other highly caustic wastes, as well as to elevated temperatures and both gamma and beta radiation, ferrocyanide decomposition has occurred in the tanks. As a result, the concentration of ferrocyanide is less than that predicted by tank inventory records. As such, C-Farm tanks have been re-categorized as safe, allowing resolution of the Ferrocyanide Safety Issue for these tanks. In the PNNL studies, ferrocyanide waste simulants were used instead of actual waste. The simulants used in these studies were primarily In-Farm simulants, prepared by WHC to mimic the waste generated when the In-Farm flowsheet was used to remove radiocesium from waste supernates in the SSTs. In the In-Farm flowsheet, nickel ion and ferrocyanide anion were added to waste supernate to precipitate sodium nickel ferrocyanide and co-precipitate radiocesium. Once the radiocesium was removed, supernates were pumped from the tanks and disposed to the ground via cribs. Later, new wastes from cladding removal processes and/or from evaporators were added.These new wastes were typically highly caustic, having hydroxide ion concentrations of over 1 M and as high as 4 M. The Aging Studies investigated possible reactions between this caustic waste and the precipitated ferrocyanide waste in a radiation field.Over a 5-year period, these studies demonstrated and characterized the aging of ferrocyanide waste simulants through dissolution and hydrolysis processes. The experiments show the ultimate products are ammonia (which is slowly radiolyzed), carbonate, and oxides or hydroxides of iron and nickel. Thus, most of the fuel value in the solid phase is consumed in the process. Any ferrocyanide tank waste that contacted highly caustic waste also would undergo similar aging processes. The rate of agi...