Aqueous hydrolysis of tallow for the production of glycerin: Model development and study on parametric sensitivity

Narayani, T.; Barnabas, Vinay; Panda, Rames C.

doi:10.1080/00986445.2018.1550391

Cited by 2 publications

(3 citation statements)

References 20 publications

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“…Let us consider an element Δ v along the height of the column (see right side of Fig. 1) 33; x is the weight fraction of glycerine in the raffinate, z is the weight fraction of hydrolysable fat in the raffinate, y is the weight fraction of glycerine in the extract, and y * is the concentration of glycerine in equilibrium with x , with the distribution constant m . Also, ρ is the density of the fat, t is the time, A is the cross‐sectional area of the hydrolyser/tower, R is the raffinate mass flow rate, E is the extract mass flow rate, δ is the raffinate fraction, K is the overall mass transfer coefficient, C p is the specific heat, w is the fat content (kilogram of glycerine per kilogram of fat basis) in raffinate, a is the interfacial area, and H is the height of the hydrolyser.…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…The results obtained in the open-loop simulation of the dynamic model for material and energy transfers can be viewed in ref. [33]. A parameter sensitivity analysis was conducted to identify which input parameter has a major impact on the process outputs, and the sensor was fixed at the most sensitive point, which was identified as 8 m from the bottom of the hydrolysis tower, where the only measured variable is the process temperature.…”

Section: Energy Balance Equationsmentioning

confidence: 99%

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Parametric Identification of a Countercurrent Aqueous Hydrolysis Process for the Production of Glycerine under Higher Pressure and Temperature

Thirunavukarasu,

Panda,

Panda

et al. 2023

Chem Eng & Technol

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Glycerine is produced by aqueous hydrolysis of tallow fat in the Twitchell process under high pressure (40–60 bar) and temperature (250–270 °C). An effort was made to improve the degree of hydrolysis under optimal operating conditions by varying the feed ratio in a 20‐L Parr reactor. The 1:4 blend of water/tallow at 256 °C and 60 bar was recorded as optimal operating conditions (non‐catalytic), yielding a degree of hydrolysis of 98.4 %. A survey shows that there is a need to find alternate operating control strategies for achieving better efficiency and safe operation. Material and energy balances across the countercurrent hydrolysis tower were developed to calculate the glycerine and free fatty acids in the raffinate and extract phases, using the first principle for dynamic analysis. The model equations were validated and used to identify simple model structures suitable for designing model‐based strategies to control the process temperature in the extraction process.

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Section: Mathematical Modelingmentioning

confidence: 99%

Section: Energy Balance Equationsmentioning

confidence: 99%

Parametric Identification of a Countercurrent Aqueous Hydrolysis Process for the Production of Glycerine under Higher Pressure and Temperature

Thirunavukarasu,

Panda,

Panda

et al. 2023

Chem Eng & Technol

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“…To achieve maximum yield/degree of hydrolysis, proper models capturing the overall dynamics are required which are done through the first principle method [37]. The mathematical model formulated here predicts the distribution of tallow in two phases (fat and aqueous) across height of the column.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis using economic model predictive control for hydrolysis of tallow fat

Thirunavukarasu

Panda

2021

Asian Journal of Control

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Tallow is a resource for glycerine and oleochemicals produced by subsequent hydrolysis, saponification, or transesterification. Since steam hydrolysis, an industrial practice, uses continuous high pressure and temperature, is energy intensive; this has been replaced by use of pressurized hot water from top and bottom of hydrolyzing tower. The fat and water form continuous phase in the heat exchange part where hydrolysis takes place in approximately 3 h. The degree of hydrolysis depends on vapor-liquid equilibrium of water which is a function of temperature and pressure. It has been found that degree of hydrolysis is feasible at 256 C. Continuous countercurrent flow is maintained by the density difference between the two phases in the heat exchange sections. There is a need for improving degree of hydrolysis along the safe operating region in the temperature-pressure domain of energy-utility spectrum by using model predictive control (MPC). A nonlinear mathematical model, representing glycerine concentration and temperature in fat and aqueous phases, for the fat hydrolysis system is used for system identification and synthesizing model-based tuning rules for the said process. Auto-tuning algorithms (multiloop with IMC-PID-Laurent tuning) are developed for PID tuning. The conventional control algorithms (IMC-PI and MPC) focus on error minimization and performance optimization; hence, economic model predictive control (EMPC) is adopted (incorporating reaction kinetics into objective function) to optimize the process utility via improved energy efficiency. A closed-loop comparison (PI, MPC, and economic MPC) of performance indices reveals that economic MPC gives satisfactory results.

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Aqueous hydrolysis of tallow for the production of glycerin: Model development and study on parametric sensitivity

Cited by 2 publications

References 20 publications

Parametric Identification of a Countercurrent Aqueous Hydrolysis Process for the Production of Glycerine under Higher Pressure and Temperature

Parametric Identification of a Countercurrent Aqueous Hydrolysis Process for the Production of Glycerine under Higher Pressure and Temperature

Performance analysis using economic model predictive control for hydrolysis of tallow fat

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