International Journal of Chemical Separation Technology
Volume 12, Issue 2 (2026)
Table of contents
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Density-Based Separation and Polymer Type Verification of Mixed Post-ConsumerThermoplastic Streams: A Sequential Separation and Contamination Reduction Protocol for Secondary Polymer Supply Chains
Abstract: The separation of mixed post-consumer thermoplastic waste streams into polymer-type-specific fractions suitable for industrial reintegration is a fundamental chemical separation challenge in secondary polymer supply chains. Density-based separation, exploiting the characteristic density ranges of common thermoplastic polymers, remains the dominant first-stage separation technique in commercial recycling operations due to its low cost, scalability, and applicability across mixed waste stream compositions. This paper presents a sequential separation and contamination reduction protocol …
Published in International Journal of Chemical Separation Technology · Vol. 12, Issue 2, 2026 Read article
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Dynamic Matrix Control Versus Nonlinear ModelPredictive Control for the Van de Vusse ContinuousStirred-Tank Reactor: Diagnosing and Correcting aCost-Function Pathology That Masked NMPC’sTrue Performance
Abstract: The Van de Vusse reaction in a continuous stirred-tank reactor (CSTR) is a benchmark for nonlinear multivariable control, but its narrow operating envelope creates a trap for nonlinear model predictive control (NMPC): when the setpoint step is small relative to the plant’s reachable range, a standard quadratic NMPC cost function can make zero control action mathematically optimal, even with a perfect prediction model. This paper documents that failure mode, traces …
Published in International Journal of Chemical Separation Technology · Vol. 12, Issue 2, 2026 · pp. 55–66 Read article