An investigation of the applicability of attenuated total reflection infrared spectroscopy for measurement of solubility and supersaturation of aqueous citric acid solutions

Dunuwila, Dilum D.; Carroll, L.; Berglund, Kris A.

doi:10.1016/0022-0248(94)90999-7

Cited by 99 publications

(108 citation statements)

References 4 publications

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“…The decrease of pH is connected to the progress of the semi-batch process with equations of equilibrium (Eqs. [1][2][3][4][5][6][7][8] and to the formation of supersaturation (see Figure 2).…”

Section: Control Of Supersaturationmentioning

confidence: 99%

“…For glutamic acid, a FTIR spectrometer with an ATR-probe seems a promising tool to measure concentration online and in situ for control purposes. [1][2][3][4]8,[29][30][31] This study is based on using ATR-FTIR to measure concentration in situ. Khan et al 4 and Grön et al 31 have used similar ATR-FTIR measurements in a feedback connection of a control structure when they studied closed loop cooling crystallization of L-glutamic acid and monosodium glutamate (MSG).…”

Section: Control Systemmentioning

confidence: 99%

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Process control and monitoring of reactive crystallization of L‐glutamic acid

Alatalo¹,

Hatakka²,

Kohonen³

et al. 2009

AIChE Journal

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The aim of the present study was to investigate feedback control of a reactive crystallization process. The present study built up a control structure needed to control the driving force of reactive crystallization using the feed rate of added acid. The concentration of the crystallizing compound and pH was used to compute feedback in the closed-loop control of semi-batch precipitation. The concentration of L-glutamic acid was determined from measured MID-IR ATR-FTIR spectra based on a multivariate model. Dynamic change of set value was based on the mass of added sulfuric acid and pH. The studied properties of the product crystals were polymorphism and crystal size. The polymorphic composition was analyzed with a Raman spectrometer and was expressed by mass fraction of the a-polymorph. The obtained results showed that the developed feedback process control system allows effective control of forming of polymorphs.

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Section: Control Of Supersaturationmentioning

confidence: 99%

Section: Control Systemmentioning

confidence: 99%

Process control and monitoring of reactive crystallization of L‐glutamic acid

Alatalo¹,

Hatakka²,

Kohonen³

et al. 2009

AIChE Journal

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“…Solving the above problem requires knowledge of the current value of the solute concentration c(t). Such concentration can be measured rather accurately in different ways, for example by densitometry or by Attenuated Total Reflectance Infra-Red spectroscopy (ATR-FTIR), the latter becoming a rather established technique in crystallization processes (Dunuwila et al, 1994;Dunuwila and Berglund, 1997;Fujiwara et al, 2002;Lewiner et al, 2001a,b;Groen and Roberts, 2001).…”

Section: Estimating 2-d Growth Ratesmentioning

confidence: 99%

Measurement of particle size and shape by FBRM and in situ microscopy

Kempkes

Eggers

Mazzotti

2008

Chemical Engineering Science

126

103

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“…The concentration was computed with a multivariate model from the ATR-FTIR spectrum [7,8,14,15,19,20,22,27,28]. FTSW-100 spectrometer software of ABB was used www.cet-journal.comwith an OPC server.…”

Section: Crystallizer and Instrumentationmentioning

confidence: 99%

“…Dunuvila's studies on analysis methodology [7,8] were the starting point of monitoring and control studies based on in situ spectroscopic measurements of solution concentrations of crystallization. Fujiwara et al [9] and Liotta and Sabesan [10] used a proportional-integral controller in cooling crystallization so that feedback concentration is measured with an ATR-FTIR in situ probe.…”

Section: Introductionmentioning

confidence: 99%

Closed‐Loop Control of Reactive Crystallization. Part I: Supersaturation‐Controlled Crystallization of L‐Glutamic Acid

Alatalo¹,

Hatakka²,

Louhi-Kultanen³

et al. 2010

Chem Eng & Technol

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The feedback control policy of the reactive crystallization process is studied. A concentration of a crystallizing compound is used to compute the feedback in the closed-loop control of semi-batch precipitation. The pH is used as a second feedback value, and the dynamic change of the set value is based on the mass of added acid. The concentration of L-glutamic acid is determined from measured MID-IR attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra based on a multivariate model. The importance of the supersaturation level control at the nucleation moment and the effect of different supersaturation levels on the quality of the product crystals are studied by using a 50-L crystallizer. The studied crystal properties of the product are polymorphism (reported metastable a-and stable b-forms) and crystal size. The results show that the feedback process control system developed in this study makes it possible to control the formation of polymorphs effectively.

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An investigation of the applicability of attenuated total reflection infrared spectroscopy for measurement of solubility and supersaturation of aqueous citric acid solutions

Cited by 99 publications

References 4 publications

Process control and monitoring of reactive crystallization of L‐glutamic acid

Process control and monitoring of reactive crystallization of L‐glutamic acid

Measurement of particle size and shape by FBRM and in situ microscopy

Closed‐Loop Control of Reactive Crystallization. Part I: Supersaturation‐Controlled Crystallization of L‐Glutamic Acid

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