Firewater storage, treatment, recycling and management : new perspectives based on experiences from the United Kingdom

Smart firewater management and recycling helps reduce water use and protect the environment from pollution. However, contamination of recycled water may pose a health risk to fire fighters. This review assesses international literature to identify best practices, and to recommend new technologies and methods on firewater management and recycling. The literature assessment indicates that this is a new research area where insufficient findings have been published in Web of Science-referenced journals. Therefore, informally published materials (a.k.a. grey literature) were also assessed. Findings indicate the need for practical decision support tools to estimate consumption rates, predict “bottlenecks” and bund capacity, assess water quality and determine pump requirements. This article recommends that cost-efficient and rapid on-site treatment methods, such as compact and mobile filtration units for firewater recycling should be researched in the future. The filters should be based on compartments with different media. The empty pore space should decrease from inflow to outflow. A light plastic media should be positioned near the inflow to retain large particles, such as a grid. Activated carbon media could be placed near the outlet to remove fine suspended solids and dissolved contaminants. This should address concerns by fire fighters dealing with contaminated water, spray and foam

Modelling the Interfacial Flow of Two Immiscible Liquids in Mixing Processes

This paper presents an interface tracking method for modelling the flow of immiscible metallic liquids in mixing processes. The methodology can provide an insight into mixing processes for studying the fundamental morphology development mechanisms for immiscible interfaces. The volume-of-fluid (VOF) method is adopted in the present study, following a review of various modelling approaches for immiscible fluid systems. The VOF method employed here utilises the piecewise linear for interface construction scheme as well as the continuum surface force algorithm for surface force modelling. A model coupling numerical and experimental data is established. The main flow features in the mixing process are investigated. It is observed that the mixing of immiscible metallic liquids is strongly influenced by the viscosity of the system, shear forces and turbulence. The numerical results show good qualitative agreement with experimental results, and are useful for optimisating the design of mixing casting processes

Optimal design of hydraulic capsule pipelines transporting spherical capsules

Scarcity of fossil fuels is affecting efficiency of established modes of cargo transport within transportation industry. Extensive research is being carried out on improving efficiency of existing modes of cargo transport, as well as to develop alternative means of transporting goods. One such alternative method can be through the use of energy contained within fluid flowing in pipelines in order to transfer goods from one place to another. The present study focuses on the use of advanced numerical modelling tools to simulate the flow within Hydraulic Capsule Pipelines (HCPs) transporting Spherical Capsules with an aim of developing design equations. Hydraulic Capsule Pipeline is the term which refers to the transport of goods in hollow containers, typically of spherical or cylindrical shapes, termed as capsules, being carried along the pipeline by water. HCPs are being used in mineral industries and have potential for use in Oil & Gas sector. A novel modelling technique has been employed to carry out the investigations under various geometric and flow conditions within HCPs. Both qualitative and quantitative flow analysis has been carried out on the flow of spherical shaped capsules in an HCP for both on-shore and off-shore applications. Furthermore, based on Least-Cost Principle, an optimisation methodology has been developed for the design of single stage HCPs. The input to the optimisation model is the solid throughput required from the system, and the outputs are the optimal diameter of the HCPs and the pumping requirements for the capsule transporting system

Aerospace Fuels From Nonpetroleum Raw Materials

Recycling human metabolic and plastic wastes minimizes cost and increases efficiency by reducing the need to transport consumables and return trash, respectively, from orbit to support a space station crew. If the much larger costs of transporting consumables to the Moon and beyond are taken into account, developing waste recycling technologies becomes imperative and possibly mission enabling. Reduction of terrestrial waste streams while producing energy and/or valuable raw materials is an opportunity being realized by a new generation of visionary entrepreneurs; several relevant technologies are briefly compared, contrasted and assessed for space applications. A two-step approach to nonpetroleum raw materials utilization is presented; the first step involves production of supply or producer gas. This is akin to synthesis gas containing carbon oxides, hydrogen, and simple hydrocarbons. The second step involves production of fuel via the Sabatier process, a methanation reaction, or another gas-to-liquid technology, typically Fischer-Tropsch processing. Optimization to enhance the fraction of product stream relevant to transportation fuels via catalytic (process) development at NASA Glenn Research Center is described. Energy utilization is a concern for production of fuels whether for operation on the lunar or Martian surface, or beyond. The term green relates to not only mitigating excess carbon release but also to the efficiency of energy usage. For space, energy usage can be an essential concern. Another issue of great concern is minimizing impurities in the product stream(s), especially those that are potential health risks and/or could degrade operations through catalyst poisoning or equipment damage; technologies being developed to remove heteroatom impurities are discussed. Alternative technologies to utilize waste fluids, such as a propulsion option called the resistojet, are discussed. The resistojet is an electric propulsion technology with a powered thruster to vaporize and heat a propellant to high temperature, hot gases are subsequently passed through a converging-diverging nozzle expanding gases to supersonic velocities. A resistojet can accommodate many different fluids, including various reaction chamber (by-)products

ZnO nanopowder derived from brass ash: Sintering behavior and mechanical properties

The present investigation studied the recycling of zinc from brass ash which is a secondary product produced during the brass smelting process. A retiring cycle was devised to produce high-purity ZnO nanopowders. Recovery of > 90 wt% of the total zinc available was achieved after the calcination of brass ash at 700 °C and a multistage hydrometallurgical treatment at room temperature. ZnO powder produced by the developed method was analyzed by X-ray diffraction, transmission electron scanning microscopy, ICP-AES and BET analysis. The ZnO nanopowder obtained from the brass ash was well dispersed and the size of the individual particles was in the range of 30–50 nm. The purity of the powder was 99.83 wt%, and the surface area was about 30.5 m2/g. A relative density level of about 98.1% was reached with ZnO pellets sintered at 1300 °C

Development of a Design Methodology for Hydraulic Pipelines Carrying Rectangular Capsules

The scarcity of fossil fuels is affecting the efficiency of established modes of cargo transport within the transportation industry. Efforts have been made to develop innovative modes of transport that can be adopted for economic and environmental friendly operating systems. Solid material, for instance, can be packed in rectangular containers (commonly known as capsules), which can then be transported in different concentrations very effectively using the fluid energy in pipelines. For economical and efficient design of such systems, both the local flow characteristics and the global performance parameters need to be carefully investigated. Published literature is severely limited in establishing the effects of local flow features on system characteristics of Hydraulic Capsule Pipelines (HCPs). The present study focuses on using a well validated Computational Fluid Dynamics (CFD) tool to numerically simulate the solid-liquid mixture flow in both on-shore and off-shore HCPs applications including bends. Discrete Phase Modelling (DPM) has been employed to calculate the velocity of the rectangular capsules. Numerical predictions have been used to develop novel semi-empirical prediction models for pressure drop in HCPs, which have then been embedded into a robust and user-friendly pipeline optimisation methodology based on Least-Cost Principle

On the accuracy of Landweber and Tikhonov reconstruction techniques in gas-solid fluidized bed applications

As electrical capacitance tomography technique needs a sophisticated reconstruction, the accuracy of two of the most widely used reconstruction techniques (Landweber and Tikhonov) for gas-fluidized bed applications were assessed. For this purpose, the results of two-fluid model simulations were used as an input of reconstruction. After finding the optimum reconstruction parameters for the studied system, it is found that both techniques were able to obtain the radial profile and overall value of average volume fraction very well. Conversely, both methods were incapable to determine bubble sizes accurately especially small bubble sizes, unless the Landweber technique with inverted Maxwell concentration model is applied. The probability distribution of the reconstructed results was also smoother in transition between the emulsion and bubble phases compared to the reality. Finally, no significant differences in noise immunity of these two techniques were observed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4102–4113, 201