| ARTICLES | Am. J. innov. res. appl. sci. Volume 2,  Issue 7, Pages 313-328 (July 2016)

Research Artcle   DYNAMIC ANALYSIS OF A CSTR FOR THE PRODUCTION OF BORIC ACID     | Ademola Stanford Olufemi | Mayowa Azeez | Oluwafemi Olayebi | and | Maureen Nkolika Unegbu |. Am. J. innov. res. appl. sci. 2016; 2(7):313-328.     | PDF FULL TEXT |                                                                   |Received | 23 June 2016|          |Accepted | 01 July 2016|         |Published 13 July 2016 |

Abstract Backgound: Most of the boric acid is produced in a CSTR by the reaction against inorganic borates obtained from borax (Na2B4O7 · 10H2O) solutions which were prepared from borax ore with sulfuric acid in an aqueous medium. The automatic control of its production are in order to (1) ensure safe operation (2) reduce raw material and energy costs and (3) meet required product specification is a commonly occurring problem in a CSTR. Objective: This contribution investigates the performance of the Model Predictive Controller (MPC) of the boric acid production system. Methods: Materials used are CSTRs, mechanical stirrer, flat bottom flask, water bath, funnel, laboratory pump, colemanite (solid). The experiment was carried out in the separation process laboratory of the chemical/petroleum engineering department, Niger Delta University, Nigeria. There are four CSTRs in the reactor system, a liquid feed tank, a colemanite feeder and a filtration unit. Result and conclusion: The reaction pathway used for the production of the acid is the reaction of colemanite and sulfuric acid in four CSTR’s connected in series. In the reactor, the product (boric acid) concentration of the fourth reactor is controlled by manipulating the sulfuric acid flow rate fed to the reactor. The concentration of borax solutions was varied from 1120 to 1240 kg/m3 and 1180 kg/m3 was determined to be the optimum concentration value for boric acid production from a relation between borax solution concentration and boric acid production yield and boric acid purity. During this reaction, gypsum (calcium sulfate dihydrate) is formed as a byproduct. The transfer functions of the process and disturbance (colemanite flow rate) were obtained experimentally by giving step (5 %) changes in the manipulated variable and to the disturbance.                            Keywords: Boric Acid, Model Predictive Control, Transfer Function, Disturbance, CSTR.