30 research outputs found
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Implementation of model predictive control on a hydrothermal oxidation reactor
This paper describes the model-based control algorithm developed for a hydrothermal oxidation reactor at the Pantex Department of Energy facility in Amarillo, Texas. The combination of base hydrolysis and hydrothermal oxidation is used for the disposal of PBX 9404 high explosive at Pantex. The reactor oxidizes the organic compounds in the hydrolysate solutions obtained from the base hydrolysis process. The objective of the model predictive controller is to minimize the total aqueous nitrogen compounds in the effluent of the reactor. The controller also maintains a desired excess oxygen concentration in the reactor effluent to ensure the complete destruction of the organic carbon compounds in the hydrolysate
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Base hydrolysis and hydrothermal processing of PBX-9404 explosive
Base hydrolysis in combination with hydrothermal processing has been proposed as an environmentally acceptable alternative to open burning/open detonation for degradation and destruction of high explosives. In this report, we examine gaseous and aqueous products of base hydrolysis of the HMX-based plastic bonded explosive, PBX-9404. We also examine products from the subsequent hydrothermal treatment of the base hydrolysate. The gases produced from hydrolysis of PBX-9404 are ammonia, nitrous oxide, and nitrogen. Major aqueous products are sodium formate, acetate, nitrate, and nitrite, but not all carbon products have been identified. Hydrothermal processing of base hydrolysate destroyed up to 98% of the organic carbon in solution, and higher destruction efficiencies are possible. Major gas products detected from hydrothermal processing were nitrogen and nitrous oxide
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Parameter Identification and On-Line Estimation of a Reduced Kinetic Model
In this work, we present the estimation techniques used to update the model parameters in a reduced kinetic model describing the oxidation-reduction re- actions in a hydrothermal oxidation reactor. The model is used in a nonlinear model-based controller that minimizes the total aqueous nitrogen in the reac- tor effluent. Model reduction is accomplished by com- bining similar reacting compounds into one of four component groups and considering the global reac- tion pathways for each of these groups. The reduced kinetic model developed for thk reaction system pro- vides a means to characterize the complex chemical reaction system without considering each chemicaJ species present and the reaction kinetics of every pos- sible reaction pathway. For the reaction system under study, model reduction is essential in order to reduce the computational requirement so that on-line imple- mentation of the nonlinear model-based controller is possible and also to reduce the amount of a priori information required for the model
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Parameter identification and on-line estimation for reduced kinetic model
The base hydrolysis process for the destruction of energetic or explosive materials results is a high pH hydrolysate solution with reaction products that include a series of carboxylic acid salts, glycolates, amines, and nitrates. The hydrolysate solutions obtained from this process contain from two to ten wt% of organic carbon and nitrogen compounds that must be further treated before disposal. Hydrothermal oxidation at elevated temperatures (450 C) and pressure (14,000 psi) was selected as the treatment process for the hydrolysate solutions obtained from hydrolysis of the high explosive PBX 9404 at the Department of Energy Pantex facility in Amarillo, Texas. In this work, the authors describe the use of receding horizon identification and estimation techniques to determine the model parameters for a reduced kinetic model describing the oxidation-reduction reactions in a hydrothermal oxidation reactor. This model is used in a model predictive controller that minimizes the total aqueous nitrogen in the hydrothermal oxidation reactor effluent
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Base hydrolysis and hydrothermal processing of PBX-9404 explosive
Base hydrolysis in combination with hydrothermal processing has been proposed as an environmentally acceptable alternative to open burning/open detonation for degradation and destruction of high explosives. In this report, the authors examine gaseous and aqueous products of base hydrolysis of the HMX-based plastic bonded explosive, PBX-9404. The authors also examine products from the subsequent hydrothermal treatment of the base hydrolysate. The gases produced from hydrolysis of PBX-9404 are ammonia, nitrous oxide, and nitrogen. Major aqueous products are sodium formate, acetate, nitrate, and nitrite, but not all carbon products have been identified. Hydrothermal processing of base hydrolysate destroyed up to 98% of the organic carbon in solution, and higher destruction efficiencies are possible. Major gas products detected from hydrothermal processing were nitrogen and nitrous oxide
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Pilot-scale base hydrolysis processing of HMX-based plastic-bonded explosives
Los Alamos National Laboratory has demonstrated that many energetic materials can be rendered non-energetic via reaction with sodium hydroxide or ammonia. This process is known as base hydrolysis. A pilot scale reactor has been developed to process up to 20 kg of plastic bonded explosive in a single batch operation. In this report, we discuss the design and operation of the pilot scale reactor for the processing of PBX 9404, a standard Department of Energy plastic bonded explosive containing HMX and nitrocellulose. Products from base hydrolysis, although non-energetic, still require additional processing before release to the environment Decomposition products, destruction efficiencies, and rates of reaction for base hydrolysis will be presented. Hydrothermal processing, previously known as supercritical water oxidation, has been proposed for converting organic products from hydrolysis to carbon dioxide, nitrogen, and nitrous oxide. Base hydrolysis in combination with hydrothermal processing may yield a viable alternative to open burning/open detonation for destruction of many energetic materials