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Start Over Descriptor "NEUTRALIZATION (Chemistry)" Publication Type Electronic Resources
2 results on '"NEUTRALIZATION (Chemistry)"'

1. On designing algorithms for controlling pH

Author

Badran, Wassim Albert and Jacobs, O. L. R.

Subjects
660, Neutralization (Chemistry), Hydrogen-ion concentration, Measurement
Abstract

This thesis describes an investigation of how techniques of modelling, estimation and control can be used to improve regulation of pH. A novel mathematical model of neutralization is used which explicitly accounts for two separate sources of non-linearities in pH systems: the inherent non-linearity of the pH measurement and the variable and uncertain non-linearity of the neutralization chemistry. A detailed interactive simulation package was developed. It has been used to study:

  • 1. The application of a Bayes' non-linear estimator to a noisy pH measurement. The estimator is used in conjunction with an Extended Kalman Filter in order to generate estimates for use in combined feedforward/feedback controllers. A novel version of the Bayes' estimator is developed which successfully estimated jumping and drifting bias on the pH measurement.
  • 2. A novel cautious stochastic control law which uses the generated estimates and allows for their uncertainty. Reduced quality of estimation forces the controller to regulate the pH at an optimally tuned target value where control is easier.
  • 3. Comparisons of a variety of modern and conventional control algorithms. The modern algorithms include three self-tuners, the non-linear estimators and the cautious controller. The conventional algorithms include a PID controller, analytical linearisation of the pH measurement and the use of estimated or measured feedforward signals. Twenty-five pH control laws are simulated.
The quality of regulation which can be achieved depends on what prior information is available about the neutralisation process. A strategy is proposed which matches controller structure to available information. This strategy provides guidelines to the control configurations that can be implemented as well as their relative limitations. It is shown that improvement in performance over a PID regulator is possible if one uses more complex controllers. This improvement is investigated by simulation because it varies from one process to another. It is also shown how the resulting simulation package has been used for computer aided design of pH control systems in the chemical industry.

Published
1984

2. Evaluation of the effectiveness of salt neutralizers for washing snow and ice equipment

Subjects
Roads Snow and ice control Equipment and supplies Corrosion., Corrosion and anti-corrosives., Neutralization (Chemistry), Protective coatings., Neutralisation (Chimie), Revêtements protecteurs., neutralization., protective coating., Corrosion and anti-corrosives., Neutralization (Chemistry), Protective coatings., Anticorrosion coatings., Corrosion protection., Winter maintenance.
Abstract

In winter maintenance, the chloride-based deicers used to keep roadways clear of snow and ice are highly corrosive to vehicles and equipment. Corrosion of snow and ice equipment is a major issue causing increased maintenance and repair costs, reduced vehicle life, and increased vehicle downtime. Statistics show that road salt causes approximately $1500/ton of damage to vehicles, bridges, and the environment. Washing of winter maintenance equipment after exposure to ice control chemicals has been suggested as one possible solution to minimize corrosion. However, washing with soap and water has been shown to be insufficient in removing residual salt from winter maintenance vehicles. Treating winter maintenance equipment with salt neutralizers, used in a variety of household and industrial applications, has been shown to prevent corrosion. Although the consensus points to the need for a reliable and easy to implement corrosion prevention strategy, at present there is not sufficient information available to determine the effectiveness of different wash systems at preventing corrosion. As the corrosion reduction data of salt neutralizer solutions on bare and coated metal surfaces is lacking, a systematic study has been carried out to provide quantitative information. A parallel study of six commercially available salt neutralizers is carried out for comparison. Analysis of the salt neutralizer solutions was carried out using contact angle, Ultra Violet-visible spectroscopy (UV-vis), and Scanning Electron Microscopy imaging (SEM). Corrosion inhibition for several metals treated with salt neutralizer was determined using potentiodynamic measurements and accelerated weight loss analysis (ASTM B117). When considering the effects of corrosion on winter maintenance equipment, it is important to study not only steel but also various "soft metals" (copper, aluminum, brass, etc.) that can be found in the wiring and other parts of the fleet. Electrical Impedance Spectroscopy and visual inspection were used to determine the ability of coated metal samples to prevent corrosion. A cost benefit analysis was completed to determine what specific conditions directly impact the cost effectiveness of corrosion prevention strategies.

Published
2014

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