Refrigerant

About: Refrigerant is a research topic. Over the lifetime, 36164 publications have been published within this topic receiving 258103 citations.

Ozone in Water Treatment : Application and Engineering

Abstract: INTRODUCTION. PURPOSE OF BOOK. CURRENT ROLE OF OZONE IN DRINKING WATER TREATMENT. History of Ozone Use. Current Status in North America. Current Status in Europe. Current Status in the Middle East and Far East. Current Status in the World at Large. THE FUTURE. FUNDAMENTAL ASPECTS. CHEMISTRY-INTRODUCTION. Molecular Ozone Reactivity. Decomposition of Ozone. Reaction With Inorganics. Oxidation of Synthetic Organic Compounds. Reaction of Ozone on Cell Constituents In Vitro. Reactions With Aquatic Humic Substances. TOXICOLOGY. Principles and Limitations of Toxicological Testing. Short-Term Mutagenicity and Genotoxicity Tests. Short-Term Bioassay for Carcinogenic/Mutagenic By-Products. Subchronic Bioassays on Nongenotoxic Ozone Disinfection By-Products. THEORETICAL ASPECTS OF OZONE ANALYSIS-INTRODUCTION. Ozone Measurements in the Gas Phase. Interferences Affecting Dissolved Ozone Measurements. Constraints of Dissolved Ozone Measurements. Reporting Gas-Phase Ozone Concentration. Ozone Measurement in the Aqueous Phase (Ozone Residual). Gas-Phase Measurements. Conclusions. OZONE GENERATION. Basic Principles. Ozone Generation By Corona Discharge. Alternative Methods. OZONE GAS TRANSFER. Solubility of Ozone in Water. Contacting of Ozone With Water. PRACTICAL APPLICATION OF OZONE: PRINCIPLES AND CASE STUDIES. INTRODUCTION. Uses of Ozone. Current Practice. IRON AND MANGANESE REMOVAL. Principles of Removal. Case Studies. Design Considerations. COLOR ABATEMENT. Definition and Origin of Color. Treatments for Color Removal. Case Study: Tullich Water Treatment Works, Oban, Scotland. Design Considerations. CONTROL OF TASTES AND ODORS. Introduction. Definition of Tastes and Odors and Evaluation Techniques. Odor- and Taste-Producing Compounds and Their Origin. Odor and Taste Elimination Processes. Case Studies: Choisy-le-Roi and Morsang-sur-Seine. Design Considerations. ELIMINATION OF SYNTHETIC ORGANIC COMPOUNDS. Uncatalyzed Ozonation. Advanced Oxidation Processes. Case Study on Ozone-GAC Treatment: Rouen La Chapelle Water Utility (Seine Maritime, France). Design Considerations. PARTICULATE REMOVAL. Principles. Case Studies. Special Considerations for Process Evaluation, Design, and Control. ALGAE REMOVAL. Problems Connected With the Presence of Plankton in the Water. Review of the Principal Treatments Currently Used for Plankton Removal. Advantages of Ozonation in Treating Plankton-Laden Water. Case Studies. DISINFECTION. Principles. Case Studies. DISINFECTION BY-PRODUCT CONTROL. Introduction. Formation of Ozonation By-Products. Primary Effects on General Disinfection By-Product Formation. Secondary Effects of Preozonation on Disinfection By-Products. Case Study: The Belle Glade Water Treatment Plant. Design of Pilot Studies for DBP Control. MINIMIZATION OF ADVERSE HEALTH EFFECTS. Introduction. Case Studies: Subchronic, Carcinogenic, and Mutagenic Effects of Ozonated Drinking Water. Unresolved Questions Concerning the Toxicology of Ozonation By-Products. Conclusions and Recommendations. BIOLOGICAL STABILIZATION. Introduction. Fundamental Aspects. Stabilization Processes. Design Considerations. ENGINEERING ASPECTS. TREATABILITY STUDIES. General Study Considerations. Study Approach. Bench-Scale Studies. Pilot- and Demonstration-Scale Studies. Parameter Measurements. Interpretation of Results. Process Recommendations. FEED GAS PREPARATION. Feed Gas Selection. Feed Gas Quality. Gas Preparation Systems. OZONE GENERATION. Commercial Scale Ozone Generator Operating Principles. Generator Technology and Materials Used. Electrical Parameters and Variables That Affect Ozone Production. Ozone Generator Cooling. Various Types of Ozone Generators. DESIGN OF CONTACT CHAMBERS AND DIFFUSION SYSTEMS. Overall Considerations. Ozone Dissolution Techniques. Contactor and Dissolution System Selection. Contactor Design Considerations. INSTRUMENTATION AND CONTROL SYSTEMS. General Considerations. Dewpoint Measurement and Drying System Control. Gas Flow Meters. Alarms. OZONE DESTRUCTION SYSTEMS. Reasons for Ozone Destruction. Current Design Practice. Other Ozone Destruction Methods. CORROSION CONSIDERATIONS AND OZONE-RESISTANT MATERIALS. Gas Preparation System. Material Selection for Ozonation Systems. RETROFIT OF OZONE SYSTEMS. Introduction. Approach to Retrofit Project Development. Process Considerations. PERFORMANCE EVALUATION. Introduction. Specification Requirements. Example Power Evaluation Test. OTHER CONSIDERATIONS. Noise Control. Structural Arrangement. CHECKLISTS FOR OZONE SYSTEM DESIGN. OPERATING AN OZONATION FACILITY. OPERATING METHODS. Air as Feed Gas. Oxygen as Feed Gas. OZONE SYSTEM RELIABILITY. Design and Standby Capacities. Reliability of Equipment. REQUIRED PLANT MAINTENANCE. Air Compressors. Aftercooler and Refrigerant Dryer. Moisture Separators and Air Filters. Desiccant Dryer. Ozone Generator. Contractor and Dissolution System. Destructor. Control Boards and Electronic Equipment. EMPLOYEE TRAINING. Operator Participation in Pilot Tests. Training Personnel During Facility Startup. Plant O & M Manuals. Troubleshooting Schedules. SAFETY. Gaseous Ozone Exposure-The Labor Code. Protection of Personnel. ECONOMICS OF OZONE SYSTEMS: NEW INSTALLATIONS AND RETROFITS. "ORDER-OF-MAGNITUDE" ESTIMATES OF OZONE SYSTEM COSTS. Procedure for Obtaining Estimated Capital Cost. Proposed Procedure for Obtaining Estimated O & M Costs. CONSIDERATIONS FOR ESTIMATING THE COST OF AN OZONATION FACILITY. Considerations for Assessing Capital Costs. Considerations for Assessing Operating and Maintenance Costs. Considerations for Assessing Secondary Benefits and Costs. INFLUENCE OF THE DESIGNED OZONATION SYSTEM ON THE CAPITAL COST. Ozone Requirement Including Standby. System Size and Housing. Availability of Power to the Site. Contactors and Associated Dissolution System. Degree of Automation. INFLUENCE OF THE DESIGNED OZONATION SYSTEM ON O & M COSTS. O & M Costs of Feed Gas Train. O & M Cost of Ozone Generation. O & M Cost of the Dissolution Systems. O & M Cost of Ozone-Containing Offgas Destruction Systems. Overview of Total O & M Costs. CASE STUDIES. Case Studies of Capital Costs. Case Studies of Operating Cost. APPENDIX A: OZONE SYSTEM TERMINOLOGY, MEASUREMENTS, AND CONVERSIONS. INTRODUCTION. STANDARD CONDITIONS. OZONE CONSIDERATION. Measuring Ozone Concentration. Ozone Concentration Conversion Factors. PRODUCT GAS OZONE PRODUCTION. OZONE TRANSFER EFFICIENCY. INDEX.

Science and technology of ammonia combustion

Abstract: This paper focuses on the potential use of ammonia as a carbon-free fuel, and covers recent advances in the development of ammonia combustion technology and its underlying chemistry. Fulfilling the COP21 Paris Agreement requires the de-carbonization of energy generation, through utilization of carbon-neutral and overall carbon-free fuels produced from renewable sources. Hydrogen is one of such fuels, which is a potential energy carrier for reducing greenhouse-gas emissions. However, its shipment for long distances and storage for long times present challenges. Ammonia on the other hand, comprises 17.8% of hydrogen by mass and can be produced from renewable hydrogen and nitrogen separated from air. Furthermore, thermal properties of ammonia are similar to those of propane in terms of boiling temperature and condensation pressure, making it attractive as a hydrogen and energy carrier. Ammonia has been produced and utilized for the past 100 years as a fertilizer, chemical raw material, and refrigerant. Ammonia can be used as a fuel but there are several challenges in ammonia combustion, such as low flammability, high NOx emission, and low radiation intensity. Overcoming these challenges requires further research into ammonia flame dynamics and chemistry. This paper discusses recent successful applications of ammonia fuel, in gas turbines, co-fired with pulverize coal, and in industrial furnaces. These applications have been implemented under the Japanese ‘Cross-ministerial Strategic Innovation Promotion Program (SIP): Energy Carriers’. In addition, fundamental aspects of ammonia combustion are discussed including characteristics of laminar premixed flames, counterflow twin-flames, and turbulent premixed flames stabilized by a nozzle burner at high pressure. Furthermore, this paper discusses details of the chemistry of ammonia combustion related to NOx production, processes for reducing NOx, and validation of several ammonia oxidation kinetics models. Finally, LES results for a gas-turbine-like swirl-burner are presented, for the purpose of developing low-NOx single-fuelled ammonia gas turbine combustors.

Reduction of hysteresis losses in the magnetic refrigerant Gd5Ge2Si2 by the addition of iron.

Abstract: The magnetocaloric effect is the change in temperature of a material as a result of the alignment of its magnetic spins that occurs on exposure to an external magnetic field. The phenomenon forms the basis for magnetic refrigeration, a concept purported to be more efficient and environmentally friendly than conventional refrigeration systems. In 1997, a 'giant' magnetocaloric effect, between 270 K and 300 K, was reported in Gd5Ge2Si2, demonstrating its potential as a near-room-temperature magnetic refrigerant. However, large hysteretic losses (which make magnetic refrigeration less efficient) occur in the same temperature range. Here we report the reduction (by more than 90 per cent) of these hysteretic losses by alloying the compound with a small amount of iron. This has the additional benefit of shifting the magnetic entropy change peak (a measure of the refrigerator's optimal operating temperature) from 275 K to 305 K, and broadening its width. Although the addition of iron does not significantly affect the refrigerant capacity of the material, a greater net capacity is obtained for the iron-containing alloy when the hysteresis losses are accounted for. The iron-containing alloy is thus a much-improved magnetic refrigerant for near-room-temperature applications.