A New Method for Production of Titanium Dioxide Pigment - Eliminating CO2 Emission

The objective of this project was to demonstrate the potential of a new process technology to reduce the energy consumption and CO{sub 2} emission from the production of titanium dioxide (TiO{sub 2}) pigment. TiO{sub 2} is one of the most commonly used minerals in the chemical manufacturing industry. It has been commercially processed as a pigment since the early 1900's, and has a wide variety of domestic and industrial applications. TiO{sub 2} pigment is currently produced primarily by the use of the so called �chloride process�. A key step of the chloride process relies on high temperature carbo-chlorination of TiO{sub 2} bearing raw materials, hence producing large quantities of CO{sub 2}. The new method uses a chemical/metallurgical sequential extraction methodology to produce pigment grade TiO{sub 2} from high-TiO{sub 2} slag. The specific project objectives were to 1) study and prove the scientific validity of the concept, 2) understand the primary chemical reactions and the efficiency of sequential extraction schemes, 3) determine the properties of TiO{sub 2} produced using the technology, and 4) model the energy consumptions and environmental benefits of the technology. These objectives were successfully met and a new process for producing commercial quality TiO{sub 2} pigment was developed and experimentally validated. The process features a unique combination of established metallurgical processes, including alkaline roasting of titania slag followed by leaching, solvent extraction, hydrolysis, and calcination. The caustic, acidic, and organic streams in the process will also be regenerated and reused in the process, greatly reducing environmental waste. The purpose and effect of each of these steps in producing purified TiO{sub 2} is detailed in the report. The levels of impurities in our pigment meet the requirements for commercial pigment, and are nearly equivalent to those of two commercial pigments. Solvent extraction with an amine extractant proved to be extremely effective in achieving these targets. A model plant producing 100,000 tons TiO{sub 2} per year was designed that would employ the new method of pigment manufacture. A flow sheet was developed and a mass and energy balance was performed. A comparison of the new process and the chloride process indicate that implementation of the new process in the US would result in a 21% decrease in energy consumption, an annual energy savings of 42.7 million GJ. The new process would reduce CO{sub 2} emissions by 21% in comparison to the chloride process, an annual reduction of 2.70 million tons of CO{sub 2}. Since the process equipment employed in the new process is well established in other industrial processes and the raw materials for the two processes are identical we believe the capital, labor and materials cost of production of pigment grade TiO{sub 2} using the new method would be at least equivalent to that of the chloride process. Additionally, it is likely that the operating costs will be lower by using the new process because of the reduced energy consumption. Although the new process technology is logical and feasible based on its chemistry, thermodynamic principles, and experimental results, its development and refinement through more rigorous and comprehensive research at the kilogram scale is needed to establish it as a competitive industrial process. The effect of the recycling of process streams on the final product quality should also be investigated. Further development would also help determine if the energy efficiency and the environmental benefits of the new process are indeed significantly better than current commercial methods of pigment manufacture

The ride comfort and energy-regenerative characteristics analysis of hydraulic-electricity energy regenerative suspension

For optimization of performances of a hydraulic-electricity energy regenerative suspension (HERS) unit, the tradeoff point was determined based on study of ride comfort and energy-regenerative characteristics of a HERS unit in this study. A HERS unit as a new energy reclaiming suspension device is equipped with an energy-harvesting hydraulic electromagnetic shock absorber (HESA). The HESA together with a quarter car was modeled based on theoretical analysis and experiments, in which the root mean square (RMS) values of the sprung mass vibration acceleration and the recovered power are regarded as the optimization objectives under different road excitation conditions such as the constraints (natural frequency, dynamic displacement, and dynamic load of wheels). The HERS unit was optimized after the relationship between the ride comfort and the energy regeneration was obtained. In comparison with the traditional suspension, the HERS unit may be utilized to improve the ride comfort and meet the vehicle-driving requirements. Moreover, the total input power may be saved by 34-100 W on average while the vibration acceleration is among 0.65-1.06 m/s2. Furthermore, it is verified that the HERS damping force control is the feasible under various load currents

Biomarkers of Oxidative Stress and Endogenous Antioxidants for Patients with Chronic Subjective Dizziness

As a neurotologic disorder of persistent non-vertiginous dizziness, chronic subjective dizziness (CSD) arises unsteadily by psychological and physiological imbalance. The CSD is hypersensitivity reaction due to exposure to complex motions visual stimuli. However, the pathophysiological features and mechanism of the CSD still remains unclearly. The present study was purposed to establish possible endogenous contributors of the CSD using serum samples from patients with the CSD. A total 199 participants were gathered and divided into two groups; healthy (n = 152, male for 61, and female for 91) and CSD (n = 47, male for 5, female for 42), respectively. Oxidative stress parameters such as, hydrogen peroxide and reactive substances were significantly elevated (p < 0.01 or p < 0.001), whereas endogenous antioxidant components including total glutathione contents, and activities of catalase and superoxide dismutase were significantly deteriorated in the CSD group (p < 0.01 or p < 0.001) as comparing to the healthy group, respectively. Serum levels of tumor necrosis factor -α and interferon-γ were significantly increased in the CSD participants (p < 0.001). Additionally, emotional stress related hormones including cortisol, adrenaline, and serotonin were abnormally observed in the serum levels of the CSD group (p < 0.01 or p < 0.001). Our results confirmed that oxidative stress and antioxidants are a critical contributor of pathophysiology of the CSD, and that is first explored to establish features of redox system in the CSD subjects compared to a healthy population

Effects of airflow on the acoustic attenuation performance of reactive muffler

In order to study the effect of airflow on the acoustic attenuation performance of reactive muffler, firstly, the formulas of wavenumber, transfer matrix method and three point method were deduced in the case of uniform flow. Then, the differences between transfer matrix method and three point method were compared based on the results of finite element method (FEM), for the no-flow, uniform flow and non-uniform flow three different cases. The results showed that both the transfer matrix method and three point method can accurately calculate the transmission loss (TL) of muffler under no-flow and uniform flow conditions. But, for the non-uniform flow case, both the results calculated by the two methods above have deviations on account of the complexity of flow field and the limitations of calculation methods. In addition, negative values even appear in the low frequency range. Finally, comparative study about the effect of uniform flow and non-uniform flow on the acoustic attenuation performance of muffler was made. Results showed that the difference of the effect of uniform flow and non-uniform flow on the acoustic attenuation performances is little when the airflow regenerated noise is ignored and the existence of airflow has little effect on the acoustic attenuation performance of reactive muffler. Therefore, the effect of airflow on the acoustic attenuation performance can be neglected during the initial phase of muffler design

A Spatial Euler-Bernoulli Beam Element for Rigid-Flexible Coupling Dynamic Analysis of Flexible Structures

A two-node spatial beam element with the Euler-Bernoulli assumption is developed for the nonlinear dynamic analysis of slender beams undergoing arbitrary rigid motions and large deformations. During the analysis, the global displacement and rotation vectors with six degrees of freedom are selected as the nodal coordinates. In addition, the “shear locking” problem is avoided successfully since the beam cross-sections are always perpendicular to the current neutral axes by employing a special coupled interpolation of the centroid position and the cross-section orientation. Then a scheme is presented where the original transient strains representing the nodal forces are replaced by proposed average strains over a small time interval. Thus all the high frequencies can be filtered out and a corresponding equivalent internal damping will be produced in this new formulation, which can improve the computation performance of the proposed element for solving the stiff problem and evaluate the governing equations even by using the nonstiff ordinary differential equation solver. Finally, several numerical examples are carried out to verify the validation and efficiency of this proposed formulation by comparison with the analytical solutions and other research works