• Energy Research
• 6. Clean water close

A prototype air cycle cooling system, designed for forced cooling of HPOF pipe-type cable, was built under an EPRI contract. Its main components are a turbine and compressor operated on a single high speed shaft and a compact cable. oil to air heat exchanger. Air cooling is supplemented by a spray water system. Tests were conducted on the prototype unit at the EPRI Waltz Mill Cable Test Facility to evaluate its performance and operating characteristics. This paper briefly describes this equipment and presents the results of the test program.

Addressing the environmental risks related to contamination of groundwater with the phenolics, benzene, toluene, ethyl benzene, xylene (BTEX) and polycyclic aromatic hydrocarbons (PAHs), which might be potentially released from the underground coal gasification (UCG) under adverse hydrogeological and/or operational conditions, is crucial in terms of wider implementation of the process. The aim of this study was to determine the main organic pollutants present in the process condensate generated during the UCG trial performed on hard coal seam in the Experimental Mine ‘Barbara’, Poland; 8,933 L of condensate was produced in 813 h of experiment duration (including 456 h of the post-process stage) with average phenolics, BTEX and PAH concentrations of 576,000, 42.3 and 1,400.5 μg/L, respectively. The Hierarchical Clustering Analysis was used to explore the differences and similarities between the samples. The sample collected during the first 48 h of the process duration was characterized by the lowest phenanthrene, anthracene, fluoranthene and pyrene contents, high xylene content and the highest concentrations of phenolics, benzene, toluene and ethyl benzene. The samples collected during the stable operation of the UCG process were characterized by higher concentrations of naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, while in the samples acquired in the post-process stage the lowest concentrations of benzene, toluene, naphthalene, acenaphthene and fluorene were observed.

AbstractInfluence of adding CuO nanoparticles in the base fluid on flow and heat transfer in an inclined half-annulus was studied considering constant heat flux as boundary condition of hot wall. Control Volume based Finite Element Method (CVFEM) is applied in order to simulate procedure. Pressure gradient source terms are eliminated by using vorticity stream function formulation. Influences of CuO volume fraction, inclination angle and Rayleigh number on hydrothermal manners are presented. Results indicate that inclination angle makes changes in flow style. The strength of eddies reaches to its minimum value when the upper wall is hot. Temperature gradient enhances with rise of buoyancy forces while it reduces with augment of inclination angle.

Abstract. The impact of multiphase reactions involving nitrogen dioxide (NO2) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism) was applied for the aqueous phase reactions, whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 µm and a liquid content (LC) of 50 µg m-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO2 with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may increase gas phase HONO levels under some conditions and that the extent of this effect is strongly pH dependent. Especially under moderate acidic conditions (i.e. pH above 4) this source may represent more than 75% of the total HONO/NO2 - production rate, but this contribution drops down close to zero in acidic droplets (as those often encountered in urban environments).

Microbial fuel cell (MFC) is a sustainable and energy efficient technology, which uses graphite as cathode for hydrogen peroxide (H2O2) production often with simultaneous power production. Nevertheless, slow kinetics of oxygen reduction reaction (ORR) at the surface of graphite often results in poor performance of MFC. In an attempt to improve the performance of MFC for in‐situ H2O2 production, a treatment of graphite cathode using nitric acid was performed. The treatment was conducted in three steps (i) heat treatment at 450°C for 2 h; (ii) acid treatment with concentrated nitric acid for 5 h; and (iii) drying at 120°C for 2 h. After the treatment, four times increase in surface area of treated cathode (GR‐HA) was observed. Energy‐dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared (FTIR) analysis revealed the presence of nitrogen and quinone based functional groups on the surface of GR‐HA. Cyclic voltammetric (CV) analysis of GR‐HA cathode further confirmed the production of H2O2 at the peak current value of −3.7 mA and on‐set potential of −0.1 V. Following CV analysis, H2O2 production experiments were performed in a dual chamber MFC using GR‐HA as cathode. Maximum 150 mg/L of H2O2 was produced with simultaneous power production of 36.438 mW/m2. Approximately, 25% increase in both H2O2 and power production was observed in the case of G cathode. Subsequently, Fenton oxidation experiments were performed (with GR‐HA and GR‐CA cathodes) to determine the efficacy of in‐situ produced H2O2. This resulted in an increase of 8.28%, 11.04%, and 31.32% in decolorization, chemical oxygen demand (COD), and Total Organic Carbon (TOC) removal efficiency, respectively. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 382–393, 2017

Summary Extraheavy-oil (XHO) reservoirs in South America represent some of the largest hydrocarbon accumulations (>500 billion bbl) in the world. Primary production (PP) that uses long horizontal wells is a commercially proved technology for XHO reservoirs. The expected ultimate recovery with primary production is generally less than 12% of original oil in place (OOIP), and thermal enhanced oil recovery (EOR) is critical for increasing recovery to 30–60% OOIP. Economic and environmentally viable thermal development of these reservoirs will require the use of horizontal steam injectors. Our results reveal that continuous steam injection (CSI) with a horizontal injector placed vertically above a horizontal producer (CSI-HIHP) is a very effective method for XHO reservoirs, with high peak-oil rate and significantly high recovery. This study, the first of its kind for an XHO reservoir, outlines an integrated work flow to evaluate the production potential of a large XHO greenfield with PP followed by thermal exploitation. The work flow, based on a probabilistic framework [involving design of experiment (DOE), proxy methods, and Monte Carlo simulations], evaluates reservoir performance for the whole life cycle of the field under a range of uncertainties, and quantifies the impact of key parameters affecting the reservoir performance. XHO reservoirs usually have significantly higher pressures than typical conventional heavy-oil reservoirs, where CSI has been applied commercially. Therefore, pressure in these reservoirs must be reduced before CSI can begin. Cyclic steam stimulation (CSS) after the initial stage of PP can be used to accelerate pressure reduction in the reservoir, while providing additional recovery. Our results demonstrate that geological features such as shale baffles have a significant impact on delaying pressure reduction during PP and CSS. Under a broad range of conditions investigated in this study, PP for 1 year followed by CSS for 4 years has been found to be successful in reducing pressure to the target pressure for CSI. High pressure drop in the horizontal steam injector can cause pressure near the toe region of the injector to be lower than the producer pressure. This results in poor steam injection and poor steam-chest development in that region, thus greatly reducing the efficiency of the thermal-recovery process. We quantify pressure drop in a horizontal steam injector and its impact on the thermal performance and suggest a novel well configuration that uses two injectors for every long producer during CSI. The proposed configuration with a sequential development plan can significantly improve economics of the projects. A novel probabilistic work flow for a full-field (FF) development plan (PP, CSS, and CSI) of XHO reservoirs provides robust production forecast during the entire life cycle. The work flow developed and the insights obtained would be very valuable in preparing effective exploitation plans and optimal facility design, a key economic variable in large projects of developing giant XHO reservoirs.

The aim of this study was to investigate the effectiveness of cultivating Parachlorella kessleri and Acutodesmus obliquus, in anaerobic digestion effluent (ADE) derived from the co-digestion of end-of-life dairy products with mixtures of agro-industrial wastes. To this end, their performance under sterile and non-sterile conditions and different ADE loadings was evaluated, in terms of biomass and lipid production, nutrient removal efficiency and vitality of the photosynthetic apparatus. 10% (v/v) ADE loading inhibited growth over 9-12days of cultivation, however biomass yields of 1.1 and 1gL-1, 22.7% and 19.5% (w/w) fatty acids concentration, as well as NH3-N assimilation of 49.7mgL-1 and 32.3mgL-1 and TP removal of 84.2% and 84% were recorded for P. kessleri and A. obliquus, respectively. Among all the ADE-based treatments tested, P. kessleri outperformed A. obliquus, with no differences observed between sterilized and non-sterilized ADE.