Studying the effect of using chitosan modified with diethylenetriaminepenta acetic acid (dtpa) to overcome scale formation in heat exchangers

In this work, chitosan and Chitosan-Ethylenediaminepentaacetic acid (DTPA) was prepared, evaluated and applied to inhibit calcium sulfate scale according to the following sequences: 1. Extraction and characterization of chitosan from shrimp shells waste. 2. Preparation and evaluation of chitosan-diethylenetriaminepentaacetic acid (DTPA) as scale inhibitor. 3. Make a comparative study of the produced scale inhibitor with other scale inhibitors such as: • Ethylenediaminetetraacetic acid (EDTA). • Sodium hexameta phosphate (SHMP). 4. Investigate experimentally the effect of the operating parameters such as, velocity, temperature, water constituents and salt concentration on calcium sulfate scale formation process 5. Evaluation the performances of these inhibitors and determine their optimal dose for maximum anti-scale effect. 6. An experimental unit was designed and coupled with a data acquisition system for a continuous measuring and monitoring the investigated parameters. The results showed that, low molecular mass chitosan samples with DD > 64% and Mw of the major component <104 was obtained by treating the chitin with 50% NaOH at 100 oC for up to 10 h. The antiscalants used in the present work have the following order for reducing calcium sulfate scaling Chitosan-DTPA < EDTA < SHMP.