On-line heuristic optimization strategy to maximize the hydrogen production rate in a continuous stirred tank reactor

• Published in: Process biochemistry (1991) Vol. 50; no. 6; pp. 893 - 900
• Main Authors: Ramírez-Morales, Juan E., Torres Zúñiga, Ixbalank, Buitrón, Germán
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2015
• Subjects: Biohydrogen production; biomass; Biomass yield; Constants; Continuously stirred tank reactors; glucose; Hydrogen production; Hydrogen yield; microorganisms; Modeling; On-line systems; Optimization; Organic loading rate; Reactors; statistical analysis; Strategy; system optimization; Tanks; Hydrogen yield; Organic loading rate; Biomass yield; Modeling; Optimization; Biohydrogen production
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2015.03.003

•A real-time optimization strategy was implemented.•The strategy was able to maximize and stabilize the hydrogen production rate.•The process was operated at the optimum state, approaching its overload limit.•The biomass yield is variable and decreases as the F/M ratio increases. This work presents a simple heuristic approach to maximize the hydrogen production rate (HPR) using an on-line optimization strategy in a continuous stirred tank reactor. An initial investigation of the relationship between the organic loading rate (OLR) and HPR was used to propose the objective function of a nonlinear optimization problem, subject to a limited range of hydraulic retention times (HRTs) and a maximum productivity standard deviation. The inlet flow was the optimized variable while the influent substrate concentration was fixed at a constant value. The results showed a maximum HPR of 25.4L H2/(Ld), reached for an optimal OLR of approximately 100g COD/(Ld) and an HRT of approximately 4h. Following the optimization strategy, the specific HPR was increased from 7.52 to 16.35L H2/(gVSSd). The hydrogen yield increased from 1.8 to 2.32mol H2/mol glucose, representing an improvement of 29%. Finally, during the optimization period, the specific hydrogen production rate increased from 3.3 to 16.35L H2/(gVSSd), which suggested that the substrate was used by hydrogen-producing biomass rather than by other competing microorganisms.