Online residence time distribution measurement of thermochemical biomass pretreatment reactors

Sievers, David A.; Kuhn, Erik M.; Stickel, Jonathan J.; Tucker, Melvin P.; Wolfrum, Edward J.

doi:10.1016/j.ces.2015.10.031

Cited by 29 publications

(14 citation statements)

References 14 publications

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“…The determination of the residence time distribution (RTD) is an important criterion for the characterization and description of any chemical plant [69][70][71][72][73]. It indicates the average residence time and potential back-mixing of molecules in the reaction apparatus and system periphery.…”

Section: Residence Time Distribution and Dead Time Measurements (Non-mentioning

confidence: 99%

Dynamically Operated Fischer-Tropsch Synthesis in PtL-Part 1: System Response on Intermittent Feed

Loewert

Pfeifer

2020

ChemEngineering

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Society is facing serious challenges to reduce CO2 emissions. Effective change requires the use of advanced chemical catalyst and reactor systems to utilize renewable feedstocks. One pathway to long-term energy storage is its transformation into high quality, low-emission and CO2-neutral fuels. Performance of technologies such as the Fischer-Tropsch reaction can be maximized using the inherent advantages of microstructured packed bed reactors. Advantages arise not only from high conversion and productivity, but from its capability to resolve the natural fluctuation of renewable sources. This work highlights and evaluates a system for dynamic feed gas and temperature changes in a pilot scale Fischer-Tropsch synthesis unit for up to 7 L of product per day. Dead times were determined for non-reactive and reactive mode at individual positions in the setup. Oscillating conditions were applied to investigate responses with regard to gaseous and liquid products. The system was stable at short cycle times of 8 min. Neither of the periodic changes showed negative effects on the process performance. Findings even suggest this technology’s capability for effective, small-to-medium-scale applications with periodically changing process parameters. The second part of this work focuses on the application of a real-time photovoltaics profile to the given system.

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Section: Residence Time Distribution and Dead Time Measurements (Non-mentioning

confidence: 99%

Dynamically Operated Fischer-Tropsch Synthesis in PtL-Part 1: System Response on Intermittent Feed

Loewert

Pfeifer

2020

ChemEngineering

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“…2 Uchida and Okamoto measured the powder flow by X-ray technology and found that increasing the pitch width of the screw decreased the transport velocity. 8 Mondal and Nabendu Ghosh studied the performance of the screw conveyor when feeding continuously at different rotational speeds. They were more conducive to particle transport and uniform mixing.…”

Section: Introductionmentioning

confidence: 99%

“…The influence of screw speed and transport volume on residence time was studied by sodium chloride tracer and conductivity method. 8 Mondal and Nabendu Ghosh studied the performance of the screw conveyor when feeding continuously at different rotational speeds. It indicated that the transport capacity of the screw conveyor was different at different rotational speeds and the shorter the screw conveyor was, the greater the influence of filling coefficient on the transport of materials was.…”

Section: Introductionmentioning

confidence: 99%

Comparison of computational fluid dynamics–discrete element method and discrete element method simulations for a screw conveyor

Wang

et al. 2019

Asia-Pacific J Chem Eng

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Flow behavior of particles is simulated by means of discrete element method (DEM) in a screw conveyor. The gas flow is considered by the Euler model. The subgrid scale model turbulence model is applied to solve gas turbulence. A detailed description of the model equations applied has been presented.The comparison between computational fluid dynamics (CFD)-DEM (i.e., considering gas flow) and DEM (i.e., not considering gas flow) simulation results is performed. Predicted mass flow rate with CFD-DEM model is in better agreement with experiments by Roberts and Wills comparing with DEM results. The effects of incline angle and filling rate on the flow behavior of particles are predicted. The simulation results show that the gas flow has a major impact on particle flow behavior at a high rotation speed, whereas the velocity of particles increases with an increase of rotation speed. As the filling rate rises, both the translational granular temperature and the rotational granular particle temperature decline, which means that the particles fluctuation turns weak. While with an increase of incline angle, from the horizontal to vertical, the translational granular temperature is increased, but the rotational granular temperature reduces and then goes up. In brief, translational motion is a main mode of motion in a screw conveyor. K E Y W O R D SCFD-DEM, filling rate, gas-solid two-phase flow, incline angle, screw conveyor

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“…These authors respectively used the following tracers or tracking techniques: titanium dioxide, pellet type of compounded CaCO3 in polymer and positron emission particle tracking. Sievers et al (2016) used NaCl as a tracer to analyse residence time distribution in a succession of screws. They found that soluble and insoluble compounds travel at the same rates in a horizontal auger tube reactor thus there is no liquid/solid stratification.…”

Section: Introductionmentioning

confidence: 99%

Residence time distribution in a biomass pretreatment reactor: Experimentation and modeling

Youssef

Ducept

Bennaceur

et al. 2017

Chemical Engineering Research and Design

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The production of cellulosic bioethanol, one of the two main possibilities of second generation biofuels, involves four dependent steps: pretreatment, enzymatic hydrolysis, fermentation and distillation. This work concerns the first step which purpose is to modify the structure of the lignocellulosic biomass hence allowing cellulose to become more accessible to enzymatic hydrolysis. In this paper, the biomass flow is characterized in a pretreatment reactor. This is done by performing residence time distribution (RTD) experiments along with the use of new methodology well adapted to our system, industrial pilot plant presenting tough thermodynamic conditions. In this novel methodology, the tracer, sodium carbonate, reacts with the acidified biomass. Our protocol consists in measuring the variation of electrical conductivity and pH at the reactor entrance and exit. Two experiments were performed in the reactor for two different theoretical residence times. A chemical model was developed allowing the determination of tracer concentrations from the measured data. The experimental residence time distributions in the reactor, obtained by deconvolution, are well represented by using CSTR and axial dispersion models. The obtained results point out the nearly plug-flow behaviour of the pretreatment reactor. 3/37

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Online residence time distribution measurement of thermochemical biomass pretreatment reactors

Cited by 29 publications

References 14 publications

Dynamically Operated Fischer-Tropsch Synthesis in PtL-Part 1: System Response on Intermittent Feed

Dynamically Operated Fischer-Tropsch Synthesis in PtL-Part 1: System Response on Intermittent Feed

Comparison of computational fluid dynamics–discrete element method and discrete element method simulations for a screw conveyor

Residence time distribution in a biomass pretreatment reactor: Experimentation and modeling

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