Inferential control of boric acid production system

Dervişoğlu, Özgecan
Inferential control of boric acid production system using the reaction of colemanite with sulfuric acid in four continuously stirred tank reactors (CSTR) connected in series is aimed. In this control scheme, pH of the product is measured on-line instead of boric acid concentration for control purposes. An empirical correlation between pH and boric acid concentration is developed using the collected data in a batch reacting system in laboratory-scale and this correlation is utilized in the control system for estimator design. The transfer function model of the 4-CSTR system previously obtained is used in the MPC controller design. In the experiments done previously for the modelling of 4-CSTR system, it was observed that the reaction goes complete within the first reactor. Therefore, the control is based on the measurements of pH of the second reactor by manipulating the flow rate of sulfuric acid given to the first reactor, while the flow rate of colemanite fed to the system is considered as disturbance. The designed controller’s performance is tested for set point tracking, disturbance rejection and robustness issues using a simulation program. It is found that, the designed controller is performing satisfactorily, using the inferential control strategy for this complex reacting system.


Dynamic Behavior of continuous flow stirred slurry reactors in boric acid production
Yücel Çakal, Gaye Ö; Eroğlu, İnci; Department of Chemical Engineering (2004)
One of the most important boron minerals, colemanite is reacted with sulfuric acid to produce boric acid. During this reaction, gypsum (calcium sulfate dihydrate) is formed as a byproduct. In this study, the boric acid production was handled both in a batch and four continuously stirred slurry reactors (4-CFSSR̕s) in series system. In this reaction system there are at least three phases, one liquid and two solid phases (colemanite and gypsum). In a batch reactor all the phases have the same operating time (...
Quantum chemical simulation of nitric oxide reduction by ammonia (scr reaction) on v2o5 / tio2 catalyst surface
Soyer, Sezen; Önal, Işıl; Department of Chemical Engineering (2005)
The reaction mechanism for the selective catalytic reduction (SCR) of nitric oxide by ammonia on (010) V2O5 surface represented by a V2O9H8 cluster was simulated by density functional theory (DFT) calculations. The computations indicated that SCR reaction consisted of three main parts. In the first part ammonia activation on Brønsted acidic V-OH site as NH4+ species by a nonactivated process takes place. The second part includes the interaction of NO with pre-adsorbed NH4 + species to eventually form nitros...
Chemical vapor deposition of boron carbide
Karaman, Mustafa; Özbelge, Önder; Department of Chemical Engineering (2007)
Boron carbide was produced on tungsten substrate in a dual impinging-jet CVD reactor from a gas mixture of BCl3, CH4, and H2. The experimental setup was designed to minimise the effect of mass transfer on reaction kinetics, which, together with the on-line analysis of the reactor effluent by FTIR, allowed a detailed kinetic investigation possible. The phase and morphology studies of the products were made by XPS, XRD,micro hardness and SEM methods. XPS analysis showed the existence of chemical states attrib...
Dissolution of colemanite and crystallization of gypsum during boric acid production in a batch reactor
Erdoğdu, Anıl; Eroğlu, İnci; Department of Chemical Engineering (2004)
One of the most commonly used boron compounds, boric acid, is produced by dissolving colemanite (2CaO₉3B2O3₉5H2O) in aqueous sulfuric acid whereby gypsum (CaSO4₉2H2O) is formed as a byproduct and must be separated from the main product. This process consists of two steps, dissolution of colemanite and formation of gypsum. The amount of boric acid formed depends on the first step, dissolution of colemanite. In the latter step, gypsum crystals are formed and stay in the reaction mixture to grow up to a size l...
Catalytic partial oxidation of propylene on metal surfaces by means of quantum chemical methods
Kızılkaya, Ali Can; Önal, Işık; Department of Chemical Engineering (2010)
Direct, gas phase propylene epoxidation reactions are carried out on model slabs representing Ru-Cu(111) bimetallic and Cu(111) metallic catalyst surfaces with periodic Density Functional Theory (DFT) calculations. Ru-Cu(111) surface is modelled as a Cu(111) monolayer totally covering the surface of Ru(0001) surface underneath. The catalytic activity is evaluated following the generally accepted oxametallacycle mechanism. It is shown that the Ru-Cu(111) surface has a lower energy barrier (0.48 eV) for the s...
Citation Formats
Ö. Dervişoğlu, “Inferential control of boric acid production system,” M.S. - Master of Science, Middle East Technical University, 2007.