Technical Basis of Scaling Relationships for the Pretreatment Engineering Platform

Abstract

Executive SummaryPacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). As part of this, the Pretreatment Engineering Platform (PEP) is designed and constructed as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," raised by the WTP External Flowsheet Review Team (EFRT). The PEP replicates the WTP leaching process using prototypic equipment and control strategies. The approach for scaling PEP performance data to predict WTP performance is critical to the successful resolution of the EFRT issue. This report describes the recommended PEP scaling approach. Results and Performance Against ObjectivesThis report describes the scale-up methodology for PEP results as authorized through Subcontract Change Number SCN-26. The technical approach was a set of internal objectives that were satisfied as summarized in Table ES.1. Review the rationale for the PEP scale of 4.5. YesThe rationale for the PEP scale of 4.5 was reviewed, documented, and endorsed.Define the technical basis for the approach in scaling PEP performance data to predict WTP performance. YesThe unit operations of the WTP replicated in the PEP were analyzed to define scaling approaches based on established engineering analysis techniques.Define how PEP performance data will be used to predict WTP performance.Yes Anticipated PEP performance data were analyzed and cross-referenced to the appropriate WTP performance parameters.Analyze the PEP system to identify scaling issues and consider their potential impacts and mitigation approaches. YesThe PEP design was considered in terms of scale-up based on maintaining similitude. A number of scaling issues were identified. A mitigating test approach was recommended.Provide input to test conduct and data requirements.Yes A test approach was recommended based on scaling issues. Quality RequirementsPNNL implements the RPP-WTP quality requirements by performing work in accordance with the River Protection Project -Waste Treatment Plant Support Program (RPP-WTP) Quality Assurance Plan (RPP-WTP-QA-001, QAP). Testing and analytical activities were performed to the quality requirements of NQA-1-1989 Part I, Basic and Supplementary Requirements, NQA-2a-1990 Task MethodologyThe task described in this report essentially involved three activities:1. A review of the applicable WTP unit operations and the PEP design and operational approach to achieve the desired M12 objectives. The PEP design was well-advanced when this task was initiated, so there was no opportunity to effect design changes. In particular, the scale factor of 4.5 (meaning the PEP is 4.5 linear times smaller than the WTP) was already established, but a review indicates its selection is sound. A review of the fundamental theory underpinning the applicable processes and physical and chemical phenomena (leaching...

Pretreatment Engineering Platform Phase 1 Final Test Report

“…The PEP was built as a 1 /4.5-scale version of the PTF because, at that scale, the ultrafiltration loop could be designed to meet two important criteria (Huckaby, (a) Kuhn et al 2008). First, when a single, 10-ft-long filter bundle with 12 full-size filter tubes is used for filtering, the ratio of solids in the feed tank to filter surface area will be the same as in the plant.…”

“…Though leaching the simulant boehmite was much slower than waste boehmite at this temperature and additional caustic was required to achieve measurable boehmite dissolution, the differences between leaching at 85ºC and 98ºC were potentially important enough to warrant this additional integrated test. The anticipated differences included impacts on mixing by air sparge mixers in Tank T02A (Kuhn et al 2008), operation of the PJMs at high temperature, and variations in the leach vessel temperature profile (i.e., more hot spots and cold spots at 98ºC).…”

“…When a process step involved Newtonian slurry, the PJMs were operated to match the mixing power per unit volume of the PTF, and when it involved non-Newtonian slurry, the PJMs were operated to match the PJM nozzle velocity of the PTF (Kuhn et al 2008). Because the transition from one set of PJM control parameters to the other generally required several hours of tuning to achieve target PJM stroke length and nozzle velocity, the transitions were only conducted between process steps.…”

“…The kinetics of aluminum dissolution required that the duration of the caustic leaching process (Kuhn et al 2008) be the same in the PEP and full-scale facilities (plant-time). The heat-up and cool-down of the caustic-leach slurry was also controlled to mimic that expected in the PTF (plant-time), so the PEP exhibited approximately the same extent of aluminum dissolution during the heat-up and cool-down.…”

“…Operation of the PEP to achieve prototypic caustic leaching was based on guidelines given in Technical Basis for Scaling Relationships for the Pretreatment Engineering Platform (Kuhn et al 2008), the process description, (b) and specific directions given in the Test Plan, Pretreatment Engineering Platform (PEP) Testing (Phase I). (c) Key operational guidelines were:…”