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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

An assessment of gas-side fouling in cement plants

The cement industry is the most energy-intensive industry in the United States in terms of energy cost as a percentage of the total product cost. An assessment of gas-side fouling in cement plants with special emphasis on heat recovery applications is provided. In the present context, fouling is defined as the buildup of scale on a heat-transfer surface which retards the transfer of heat and includes the related problems of erosion and corrosion. Exhaust gases in the cement industry which are suitable for heat recovery range in temperature from about 100 to 1300 K, are generally dusty, may be highly abrasive, and are often heavily laden with alkalies, sulfates, and chlorides. Particulates in the exhaust streams range in size from molecular to about 100 micrometers in diameter and come from both the raw feed as well as the ash in the coal which is the primary fuel used in the cement industry. The major types of heat-transfer equipment used in the cement industry include preheaters, gas-to-air heat exchangers, waste heat boilers, and clinker coolers. At the present time, the trend in this country is toward suspension preheater systems, in which the raw feed is heated by direct contact with the hot kiln exit gases, and away from waste heat boilers as the principal method of heat recovery. The most important gas-side fouling mechanisms in the cement industry are those due to particulate, chemical reaction, and corrosion fouling.

Marner, W. J.↗
NASA NTRS1985

Monitoring Marine Microbial Fouling

Two techniques developed for studying marine fouling. Methods originally developed to study fouling of materials used in Space Shuttle solid fuel booster rockets. Methods used to determine both relative fouling rates and efficacy of cleaning methods to remove fouling on various surfaces including paints, metals, and sealants intended for marine use.

Colwell, R.↗
DOE OSTI2025

Complete coverage fouling model for constant flux crossflow ultrafiltration and experimental validation

A complete coverage model is proposed to describe fouling in constant flux crossflow ultrafiltration. Constant flux crossflow fouling experiments were conducted using dilute latex bead suspensions and commercial poly(ether sulfone) flat sheet ultrafiltration membranes to investigate the influence of operating conditions on evolution of transmembrane pressure (ΔP, TMP) with time. Changes in permeate flux or crossflow rate had little influence on the normalized TMP profile at high latex bead concentration (i.e., above 25 ppm) because the membrane surface was covered with latex beads. At low concentration (i.e., below 25 ppm), increases in permeate flux or foulant concentration increased normalized ΔP. However, this increase in normalized ΔP with permeate flux or foulant concentration diminishes when the permeate flux/concentration is high enough to overwhelm particle removal due to crossflow. Furthermore, these results are in good agreement with the new complete coverage model which describes the influence of operating parameters on fouling better than the previous model.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Emulsion separation and fouling of electrospun polyacrylonitrile membranes for produced water applications

Produced water (PW) is a complex mixture generated during oil and gas extraction. Membrane fouling by hydrocarbon emulsions (sizes < 10 µm) challenges most PW treatment systems. Electrospinning has the possibility of creating microporous membranes that present unique performance properties, though evaluations of these characteristics are largely restricted to unrealistic dead-end configurations. Three different nanofibrous polyacrylonitrile (PAN) membranes were synthesized by electrospinning and their performances contrasted with a commercially available PAN membrane. Feed solutions included synthetic oil and solvent emulsions and a PW from an operating well-site. Two nanoparticles, polyaniline (PANI) and reduced graphene oxide (RGO), were studied for enhancing the oleophobicity and fouling properties of the electrospun PAN membranes. Electrospun membranes showed higher porosities (68 to 80 %) and water permeance values (9,000 to 10,000 LMH/bar) relative to that for the commercially available PAN membrane (44 % and 8,800 LMH/bar). All electrospun membranes provided superior performance characteristics when treating the emulsions and PW relative to the commercial membrane. Furthermore, the PANI integrated membrane demonstrated the greatest resistance to oil/solvent emulsion fouling and comparable performance to the RGO and PAN membrane treating the PW.

03 NATURAL GAS↗
DOE OSTI2020

Application of electrodialysis pretreatment to enhance boron removal and reduce fouling during desalination by nanofiltration/reverse osmosis

we report membranes have emerged as promising technologies for treatment of non-traditional waters, but fouling and poor rejection of small, neutral solutes (e.g., boric acid) impede their further implementation for water purification. Boron rejection is increased by raising the pH to convert boric acid to borate ion, but this change often leads to calcite supersaturation. This study investigated the use of a hybrid electrodialysis-nanofiltration/reverse osmosis (ED-NF/RO) system to reduce fouling from calcite precipitation and calcium-polysaccharide sorption to NF/RO membranes. Also, the study examined the potential of the hybrid process to increase permeate flux and boron rejection during NF/RO of synthetic saline water. ED pretreatment reduced calcite oversaturation and reduced flux decline during NF/RO. Low alginate concentrations (25 mg/L) limited NF/RO fouling, but high concentrations (100 mg/L) appeared to promote calcite scaling. ED pretreatment reduced the osmotic pressure of the NF/RO feed water, enabling lower operating pressures or greater permeate water fluxes. Boron rejection during NF/RO increased with ED pretreatment, probably due to stronger electrostatic repulsion and an increase in the fraction of total boron present as B(OH)4- following ED. This hybrid ED-NF/RO system shows promise as a novel approach to enhancing the performance of current membrane systems for treating complex feed waters.

alginate↗
DOE OSTI2025

Jupyter notebooks for analyzing transmission SAXS/WAXS from beamline 7.3.3 during operando membrane fouling experiments v1.0

This software consists of python-based Jupyter Notebooks for processing transmission x-ray scattering images collected at beamline 7.3.3 at the Advanced Light Source. The measurements considered in these analyses are collected during membrane fouling experiments, where contaminants in the water deposit on/attach to the membrane surface. This software is used to elucidate the mechanisms of membrane fouling that occur during these operando membrane fouling experiments, but the analyses provided in these scripts can be extended to other scientific cases.

Landsman, Matthew [Lawrence Berkeley National Labo↗
NASA NTRS1984

A survey of gas-side fouling measuring devices

A survey of measuring devices or probes, which were used to investigate gas side fouling, was carried out. Five different types of measuring devices are identified and discussed including: heat flux meters, mass accumulation probes, optical devices, deposition probes, and acid condensation probes. A total of 32 different probes are described in detail and summarized in matrix or tabular form. The important considerations of combustion gas characterization and deposit analysis are also given a significant amount of attention. The results show that considerable work was done in the development of gas side fouling probes. However, it is clear that the design, construction, and testing of a durable, versatile probe - capable of monitoring on-line fouling resistances - remains a formidable task.

Marner, W. J.↗
DOE OSTI2025

Fouling behavior of zwitterionic membranes compared to polyamide membranes

Membrane fouling remains a critical bottleneck for reverse osmosis (RO) desalination, driving energy consumption and reducing membrane lifetime. Here, we employ all-atom molecular dynamics simulations to investigate the antifouling behavior of random zwitterionic amphiphilic copolymer (r-ZAC) membranes composed of sulfobetaine methacrylate (SBMA) and allyl methacrylate (AMA), benchmarked against conventional polyamide (PA) RO membranes. Structural and dynamical analyses—including radial distribution functions, coordination numbers, tetrahedral order parameters, vector orientation, and residence-time correlation functions—reveal that r-ZAC surfaces sustain tightly bound, long-lived hydration layers with preserved tetrahedrality and anisotropic water orientation, in sharp contrast to the weak and disordered hydration of PA. Steered molecular dynamics simulations demonstrate that r-ZAC membranes impose substantial free-energy barriers to foulant approach (alginate ≈ 90 kcal/mol, sucrose ≈ 35 kcal/mol, humic acid ≈ 15 kcal/mol), whereas PA membranes exhibit negligible barriers (< 1 kcal/mol) and thermodynamically favorable adsorption. Detailed foulant–surface interaction analyses show that zwitterionic hydration and electrostatic heterogeneity in r-ZAC suppress adhesion, except in the case of amphiphilic humic acid, which exploits multiple binding modes. Together, these results establish molecular-level design principles for antifouling membranes: the combination of zwitterionic hydration, structured interfacial water, and controlled amphiphilic balance in r-ZAC membranes provides superior resistance to organic fouling relative to PA.

Cross-linked polyamide↗
DOE OSTI2023

CFD modeling of crystallization fouling with CO 2 desorption incorporated for a falling-film evaporator in thermal desalination

Seawater flowing around horizontal tubes in falling-film evaporators is a common configuration for thermal desalination. Heat is transferred from in-tube steam condensation to the shell-side seawater by conduction through the tube wall and scaling layer, and conduction and convection to the evaporating liquid film. CO 2 is simultaneously released from seawater and mixed with the produced vapor. Fouling coupled with CO 2 desorption has deleterious impacts on both evaporation and condensation. The evaluation of spatiotemporal dependent crystallization fouling and CO 2 desorption is vital to selecting optimal operating conditions. Here, in this work, a CO 2 desorption model is integrated into CFD modeling for predictions of coupled heat and mass transfer, to understand and predict scale formation and CO 2 desorption with local and transient profiles of temperature, carbonate species concentrations, pH, and total alkalinity. The porosity of the scale layer is experimentally determined as 67.7% and invoked in the calculation of effective thermal conductivity. The simulation results reveal that high steam temperatures increase seawater total alkalinity and accelerate scale formation. The scale thickness on the bottom tube reaches 0.30 μm and 5.24 μm for steam temperatures of 60 °C and 80 °C, respectively. High salinity leads to a large CO 2 desorption rates. The CO 2 desorption rate increases 43% when the seawater salinity increases from 35 to 55 g/kg. The effects of operating conditions on carbonate speciation and pH have been compared and analyzed. This model can serve as a comprehensive tool for the design of thermal desalination systems and optimal operation.

42 ENGINEERING↗
DOE OSTI2021

Modeling of crystallization fouling on a horizontal-tube falling-film evaporator for thermal desalination

Scale formation within horizontal-tube falling-film evaporators is an important issue for thermal desalination, because of the deterioration of heat transfer performance and added maintenance costs. Predicting the fouling process is crucial for desalination plant design, operation, and maintenance. In this paper, a model is developed to predict the crystallization fouling process during seawater falling-film flow over a horizontal tube bundle. The scaling is estimated based on deposition theory, with couple heat transfer including the in-tube steam condensation, conduction through the tube wall and the scale layer, and falling-film evaporation. The spatial and temporal variations of temperature, heat transfer coefficient, and scale thickness are predicted, and the effects of variations in process parameters of steam, feed seawater, and tube properties on the scale thickness, evaporation rate, and heat transfer coefficient for falling-film evaporation are analyzed. Comparisons to existing experimental data show the scaling layer thickness falls in the general range of reported measurements, with a slight overestimation due to neglecting the delay of scaling onset under real conditions. The scale layer thickness increases dramatically as the in-tube steam pressure is increased or the seawater flow rate is decreased. In general, the scaling layer becomes thicker on the lower tubes in the tube bundle, due to the heat and mass transfer of the falling film. The effect of tube material on scaling appears mainly dependent on thermal conductivity; thus, using polymer rather than a stainless steel tube decreases scaling and evaporation rate 96% and 88%, respectively. Finally, this work has potential to guide thermal desalination plant design, material selection, and operating parameter optimization.

42 ENGINEERING↗
DOE OSTI2022

FOULING MITIGATION FOR LASER IGNITERS IN NATURAL GAS ENGINES

Due to several recent developments in lasers and optics, laser igniters can now be designed to be (i) compact so as to have the same footprint as a standard spark plug, (ii) have low power draw, usually less than 50 Watts, and (iii) have vibration and temperature resistance at levels typical of reciprocating engines. Primary advantages of these laser igniters remain (i) extension of lean or dilution limits for ignition of combustible mixtures, and (ii) improved ignition at higher pressures. Recently, tests performed in a 350 kW six-cylinder stationary natural gas reciprocating engine retrofitted with these igniters showed an extension of the operational envelope to yield efficiency improvements of the order of 2.6% points while being compliant with the mandated emission regulations. Even though laser igniters offer promise, fouling of the final optical element that introduces the laser into the combustion chamber is of concern. After performing a thorough literature search, a test plan was devised to evaluate various fouling mitigation strategies. The final approach that was used is a combination of three strategies and helped sustain an optical transmissivity exceeding 98% even after 1500 h of continuous engine operation at 2400 rpm. Based on the observed trend in transmissivity, it now appears that laser igniters can last up to 6000 h of continuous engine operation in a stationary engine running at 1800 rpm.

spark ignited engines, laser ignition, natural gas↗
DOE OSTI2024

Ash Fouling Free Regenerative Air Preheater for Deep Cyclic Operation

The University of Kentucky (UKy) project titled “Ash Fouling Free Regenerative Air Preheater for Deep Cyclic Operation”, DE-FE0031757, was conducted from 8/15/2019 to 8/14/2024 in two Budget Periods. Other participants included PPL Corporation and Black Dragon Double Boiler. The overall goal was to investigate the proposed self-cleaning technology to achieve ash fouling free air preheater operation in a coal-fired power plant, especially during deep cycling. All project deliverables, milestones, and success criteria were met. UKy obtained the following scientific findings. • Temporary and periodic high temperature of heating elements (450 ~ 500 °F) can prevent ash accumulation and maintain air preheater free of clogging. • The ash samples analysis and unit operation provide solid evidence of ABS formed during low load with SCR ammonia slip being the major cause of ash accumulation, and air preheater clogging can be prevented by raising the heating element temperature up to 450 °F~ 500 °F at which ABS is decomposed. • In-situ self-cleaning can be controlled by monitoring temperature and/or presetting fixed number of cleanings per day. Both approaches in pilot testing show positive results for maintaining an ash free state for the air preheater. • Temperature criteria (cold end or gas outlet temperature) for entering self-cleaning service is critical to balance the number of cleaning cycles with maintaining the ash level. • Temperature criteria (cold end or gas outlet temperature) for exiting self-cleaning service is critical to balance the duration of the cleaning cycles with maintaining the ash level.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Simple Bioparticle Filtration Device Based on an Ultralow-Fouling Zwitterionic Polyurethane Membrane for Rapid Large-Volume Separation of Plasma and Viruses from Whole Blood

Plasma separation from whole blood is oftent required as an essential first step when performing blood tests with a viral assay. However, developing a point-of-care plasma extraction device with a large output and high virus recovery remains a significant obstacle to the success of on-site viral load tests. Here, we report a portable, easy-to-use, cost-efficient, membrane-filtration-based plasma separation device that enables rapid large-volume plasma extraction from whole blood, designed for point-of-care virus assays. The plasma separation is realized by a low-fouling zwitterionic polyurethane-modified cellulose acetate (PCBU-CA) membrane. The zwitterionic coating on the cellulose acetate membrane can decrease surface protein adsorption by 60% and increase plasma permeation by 46% compared with a pristine membrane. The PCBU-CA membrane, with its ultralow-fouling properties, enables rapid plasma separation. The device can yield a total of 1.33 mL plasma from 10 mL whole blood in 10 min. The extracted plasma is cell-free and exhibits a low hemoglobin level. In addition, our device demonstrated a 57.8% T7 phage recovery in the separated plasma. The results of real-time polymerase chain reaction analysis confirmed that the nucleic acid amplification curve of the plasma extracted by our device is comparable to that obtained by centrifugation. With its high plasma yield and good phage recovery, our plasma separation device provides an excellent replacement for traditional plasma separation protocols for point-of-care virus assays and a broad spectrum of clinical tests.

36 MATERIALS SCIENCE↗
NASA NTRS1980

Fouling and the inhibition of salt corrosion

In an attempt to reduce fouling while retaining the beneficial effects of alkaline earth inhibitors on the hot corrosion of superalloys, the use of both additives and the intermittent application of the inhibitors were evaluated. Additions of alkaline earth compounds to combustion gases containing sodium sulfate were shown to inhibit hot corrosion. However, sulfate deposits can lead to turbine fouling in service. For that reason, dual additives and intermittant inhibitor applications were evaluated to reduce such deposit formation. Silicon in conjunction with varium showed some promise. Total deposition was apparently reduced while the inhibition of hot corrosion by barium was unimpaired. The intermittant application of the inhibitor was found to be more effective and controllable.

Deadmore, D. L.↗
DOE OSTI2020

Method for preventing fouling of a demister

A method for preventing fouling of a demister is disclosed. A process fluid is provided into a vessel. A gas is provided to a gas inlet of the vessel. The gas comprises a component that desublimates, crystallizes, solidifies, reacts, or a combination thereof, in the process fluid, forming a first solid. The gas is passed through the process fluid, the component of the gas forming the first solid, resulting in a component-depleted gas. The component-depleted gas is passed out of the process fluid, causing splashing or spurting of the process fluid and the first solid. The diverter section is provided between the demister and the gas inlet, the diverter section comprising a physical obstruction preventing the process fluid and the first solid from splashing or spurting onto the demister. In this manner, fouling of the demister is prevented.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗