Ice Melting Capacity Research Articles

Enhanced chloride-free snow-melting agent generation from organic wastewater by integrating bioconversion and synthesis

In this study, a new process for producing chloride-free snow-melting agents (CSAs) was proposed. Organic wastewater was converted to total volatile fatty acids (TVFA) by anaerobic acidogenic fermentation. The experiments for acid generation showed that the maximum TVFA concentration of 45.9 g/L was obtained at an organic loading rate of 5 g chemical oxygen demand /(L·d), and the proportion of acetic acid reached 78.8 %. Forward osmosis was used for concentrating the TVFA solution. The obtained CSAs, after evaporation and crystallization, had a better ice-melting capacity and less corrosion on metal and concrete than NaCl and CaCl2. Additionally, the damage caused by CSAs to the germination of plant seeds was significantly lesser than that caused by chloride salts. This study proposed a feasible method for the high-value conversion of organic wastewater, providing a new direction for the reuse of organic wastewater.

Preparation and Application of a Novel Slow-Releasing with Core-Shell Deicer in Asphalt Mixtures.

The massive application of chloride salts has a direct effect on the corrosion of structures and vehicles and decreases durability as well as road pavement damage. A novel slow-release deicer with a core-shell structure was prepared to reduce the salts’ impacts, subsequently characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). The conductivity evaluation, moisture absorption, and the snow or ice melting performance of the deicer were also tested. The core-shell deicer with different replacement rates was used to prepare the deicing asphalt mixture based on the equivalent volume replacement method. In this study, the high- and low-temperature performance, moisture damage resistance, and snow or ice melting capacity of mixtures were evaluated in the laboratory. The results show that the low-temperature and moisture stability performances decreased, and high-temperature performance improved, as the content of the core-shell deicer was increased. It is confirmed that the replacement rate of the deicer filler should be lower than 75% to meet the specification requirements. The prepared deicing asphalt mixture has good snow and ice melting performance and can reduce the bonding strength between ice and pavement surface. Durability and cost–benefit analysis are expected in further investigations.

Improving the ice-melting capacity of traditional deicers

Deicers with low freezing point depression and rapid ice-melting capacity are ideal for winter maintenance of pavements located in snow-prone regions. The current study aims 1) to improve the ice-melting capacity of traditional rock-salt deicer at very low temperatures (0 °C, −10 °C, −20 °C, and −30 °C) by employing bio-based non-toxic corn-derived polyols, 2) to evaluate the skid resistance of the pavements when the polyol-modified deicing solutions are applied on the pavement surface, and 3) to determine the viscosity of the polyol-modified deicing solutions. The deicers investigated herein are prepared by adding three corn-derived polyols (sorbitol, mannitol, and maltitol) to the traditional deicing solution (23.3% wt. salt brine deicer) in varying weight concentrations (5%, 10%, 15%, and 27.7%). The ice-melting capacity of the deicing solutions is evaluated by conducting ice-melting tests at different low temperatures using an in-house built ice-melting test setup. The viscosity of the deicing solutions, the skid resistance of the pavement surfaces, and dissolved oxygen values are then evaluated corresponding to the deicer combinations that resulted in high ice melting capacity. For temperatures up to −20 °C, the increase in the concentration of corn-derived polyols led to an increase in the ice melting capacity of the deicing solutions. Among the investigated additives, the mannitol and salt brine combination (27.7% wt. mannitol + 23.3% wt. salt brine) resulted in two times more ice melting at −20 °C when compared to the 23.3% wt. salt brine alone. The viscosity of the reference deicing solutions increased by up to 23.3% after the addition of optimal amounts polyols (27.7% wt. sorbitol or maltitol or mannitol) in the deicing solutions. The skid resistance tests revealed that the application of the polyol-based deicing solution on the pavements led to up to 33% reduction in the skid resistance of the Portland cement concrete pavement when compared to the skid resistance of dry pavement surface. Moreover, the polyol-modified deicers exhibited up to 64% higher viscosity and resulted in up to 33% consumption of dissolved oxygen in river water when compared to the salt brine deicer.

Eco-friendly deicer prepared from waste oyster shells and its deicing properties with metal corrosion

ABSTRACT Calcium acetate eco-friendly deicer was prepared using waste oyster shell as a raw reactant material and its physicochemical properties were investigated. The waste oyster shells were converted to a calcium acetate deicer by reaction with acetic acid at ambient temperature. The physicochemical properties of the prepared calcium acetate deicer were analysed using various analytical method. The ice melting and metal corrosion characteristics of the calcium acetate deicer synthesized from the waste oyster shell were evaluated by comparison with those of the calcium chloride and sodium chloride deicers. The chloride deicers severely corroded the metal, but the calcium acetate deicer prepared from the waste oyster shell did not cause metal corrosion. The ice melting performance of calcium acetate prepared from the waste oyster shell was lower than that of calcium chlorides, however, the addition of sodium hydroxide could significantly improve the ice melting capacity.

Justification of ice melting capacity on 6-10kV OPL distributing power networks based on fuzzy modeling

Justification of ice melting capacity on 6-10kV OPL distributing power networks based on fuzzy modeling

Design and Preliminary Experiment of Portable Device for Melting Thin Ice on The Highway Road

Removal of thin ice and accumulated snow on the highway road snow is agent problem to be solved in the southern China. We proposed a heating method to remove the thin ice and snow on the highway road. Theoretical analysis was conducted to prove the feasibility by burning diesel oil for heating. The ice and snow are effectively melted with little diesel oil. A heating device model was proposed accordingly. The specific 3D structure was designed according to the presented proposal. To verify the ice melting capacity of the device, a preliminary experiment melting ice is conducted. Experimental result shows that the ice was quickly melted with low consumption of the fuel. With further optimization of device structure, a portable device for removal of thin ice and snow on the highway road will have a wide range of applications in southern China.

The Effect of Additives on the Low Temperature Ice-Melting Capacity of NaCl

Winter maintenance of high-traffic volume roads requires chemicals for the strategy of obtaining sufficient friction. Challenges often arise in very cold temperatures because the effect is reduced. To improve the low temperature ice-melting capacity of road salt, additives are sometimes used. There is a lack of knowledge as to how these additives affect low temperature ice-melting capacity. The tests often use SHPR H-205.1 and H-205.2; however, recent research has shown that the SHRP tests produce inaccurate results. This paper uses calorimetry to study the effect of additives on the low temperature ice-melting capacity of sodium chloride (NaCl). Magnesium chloride (MgCl2), calcium chloride (CaCl2), potassium formate (KFo), calcium magnesium acetate (CMA), and sugar (sucrose) were added to NaCl at −18°C. The chemicals were also tested individually. The measurements were done in a recently improved custom-made calorimeter, described in the paper. The results showed that solid chemicals had a far higher melting capacity than solutions. In a solid state NaCl had the highest ice-melting capacity, however, the results differed for solutions, where brine had the lowest. CaCl2had the highest ice-melting capacity of the solutions, melting 285% more than NaCl at −18.6°C. This was followed by MgCl2, KFo, mix NaCl/CaCl2, mix NaCl/CMA, CMA, and mix NaCl/MgCl2. The improvements using chlorides (MgCl2and CaCl2) depended on the amount of additive. KFo had a destructive influence on melting capacity when mixed with NaCl, whereas mixing CMA with NaCl produced a higher melting capacity than the two components individually. Sugar froze at −18°C.

The effect of mass diffusion on the rate of chemical ice melting using aqueous solutions

In wintertime, deicing chemicals are an important tool for keeping roads and runways free from snow and ice. The most common deicing chemical is sodium chloride. However, sodium chloride has a negative impact on the environment, and it is corrosive to vehicles and roadside structures. In addition, sodium chloride has been found to be ineffective at low temperatures. To overcome these issues, there is an ongoing effort to find better deicing chemicals. A part of this effort includes tests of, for example, ice melting performance, such as melting capacity and rate. Although the ice melting capacity is fairly well understood, the melting rate is not. Therefore, an experiment was designed to melt ice using aqueous solutions of nine different chemicals. The purpose was to better understand the underlying mechanisms controlling the ice melting rate. Specifically, we examined the role of diffusive flux on the melting rate of ice. Our results show that for a given chemical, a lower solution freezing point provides a larger driving force for diffusion and results in faster melting. However, the differences between different chemical solutions of the same freezing point were large, and they appeared to be related to the chemical diffusivity in water. The diffusive flux, a combination of driving force and diffusivity, correlated well with the ice melting rate. This indicates that the chemical melting rate of ice was rate-limited by mass diffusion. However, the correlation between diffusive flux and ice melting rate was only present when using notations designed for non-ideal systems. The classic Fick's law could not be related to the ice melting rate. This implied that thermodynamic properties such as chemical potential and activity were better descriptors of concentrated deicing solutions than concentration.

Effect of Prewetting Brines and Mixing on Ice-Melting Rate of Salt at Cold Temperatures: New Tracer Dilution Method

A novel test method has been developed to measure the ice-melting rate of deicers. The ice-melting rates of prewetted salt were determined by measuring the change in the concentration of chloride (Cl−) or magnesium or calcium cations (Mg2+ or Ca2+, respectively) in the ice melt as tracers. The method is substantially more precise than the SHRP H205.1 standard and has the further advantage of measuring ice-melting and salt dissolution rates simultaneously. Brines were preequilibrated with ice at −19.3°C (−2.7°F) and blended with solid salt to determine the effect of different prewetting brines on the ice-melting rate of the solid salt component only. The measured equilibrium ice-melting capacity of sodium chloride (NaCl) agreed well with the theoretical value calculated from the NaCl freezing point curve. Under a condition of no mixing, solid salt yielded 0.87% of its total available ice-melting capacity after 60 min when wetted with NaCl brine and 9.7% when wetted with calcium chloride (CaCl2) brine. Mixing raised the yield of ice melt to 27.1% and 50.5% after 60 min when wet with NaCl and CaCl2 brines, respectively. The CaCl2 brine was slightly more effective than the magnesium chloride (MgCl2) brine at enhancing the ice-melting rate of salt. The test method promises to be a useful tool for permitting a more precise optimization of prewetting brine composition, concentration, and brine-to-salt ratio at different temperatures. The method may also permit better determination of the cost-effectiveness of different prewetting strategies and provide deeper insights into the mechanism of chemical ice melting.

Use of Calorimetry to Measure Ice-Melting Capacity

The ability to melt snow and ice is an important feature of any deicing chemical or product. This ability is called the “melting capacity” and is defined as the grams of melted ice per gram of deicer. A product’s melting capacity determines its applicability for use in snow and ice control. The standard procedures in the United States for measuring melting capacity are SHRP H-205.1 for solid chemicals and H-205.2 for liquid chemicals. However, these test methods have proved to be inadequately accurate for research purposes. There is a growing need to develop improved procedures as more deicing products are released on the market. This paper describes how calorimetry, which measures the heat changes that occur during a process, may be used to measure melting capacity. A calorimeter was custom made for the research described in this paper. The calorimeter required minimal mechanical handling and had high-precision temperature control that excluded the most extreme causes of measurement errors in previously developed test methods. Liquid sodium chloride was tested and compared with the calculated melting capacity. The calorimeter produced accurate results. Tests were also performed on magnesium chloride; the results demonstrated that magnesium chloride had a higher melting capacity than sodium chloride.

Impacts of Potassium Acetate and Sodium-Chloride Deicers on Concrete

AbstractThe use of deicers in cold regions has raised many concerns regarding their negative impacts on the durability of concrete infrastructure. Numerous studies have been conducted in the laboratory settings with respect to the chemical and physical deterioration of concrete as a function of deicer type. However, little research has been done with concrete structures in the field, especially concrete bridge decks whose durability is also affected by temperature cycling and mechanical loadings. In this study, the effects of sodium chloride (NaCl) and potassium acetate (KAc) deicers were investigated using concrete samples obtained from the field bridge deck coring and those prepared in the laboratory. The relevant tests of both the field-cored and laboratory-fabricated concrete samples revealed that the two deicers (NaCl and KAc) imposed negative impact on the durability of the concrete materials. To compare the practical implications of these two deicers on concrete, their ice-melting capacity was test...

Effectiveness of Liquid Agricultural By-Products and Solid Complex Chlorides for Snow and Ice Control

AbstractAgro-based products and complex chlorides/minerals (CCM) based products are increasingly employed in snow and ice control operations, either used alone or more commonly as additives for chloride-based products. Recent studies have shown that agro-based or CCM-based products have the potential to improve the overall deicing and/or anti-icing performance and reduce the corrosion and environmental risks. However, the effectiveness of such products has been limited to qualitative field observations, and their specific role in snow and ice control is poorly understood. This work consists of a systematic laboratory investigation, which focuses on the thermal properties, ice melting behavior, and corrosivity of four agro-based deicers and two CCM based deicers. First, CCM-based deicers do not exhibit significantly better ability to lower the freezing point of water when compared with NaCl, but they feature slightly better ice melting capacity at −9.4°C (15°F) than NaCl. Second, agro-based additives appea...

Deicers based on magnesium and calcium nitrates

Based on a study of the phase equilibria in cuts of a Mg(NO3)2–Ca(NO3)2–H2O system at temperatures of 0 to–50°C, new deicers have been developed, including a liquid solution of magnesium and calcium nitrates and a solid composition of dehydrated nitrates. The ice-melting capacity of the agents under equilibrium conditions was determined. It was established that agents made of dehydrated magnesium and calcium nitrates interact with ice via heat release, which accelerates ice melting. The corrosion activity of liquid of a nitrate agent toward metals (in the collaboration with the All-Russian Institute of Aviation Materials) was determined. It was established that it can be significantly decreased at the introduction of a corrosion inhibitor. The possibility of synthesizing agents from natural mineral raw materials (dolomite, magnesite, and calcite) has been considered.

Accuracy of Ice Melting Capacity Tests: Review of Melting Data for Sodium Chloride

In cold climate regions, chemicals are often applied on roads to facilitate snow and ice removal. A commonly used performance indicator is the ice melting capacity. There is a growing need for stakeholders to measure melting capacity as more commercial products for deicing become available. There are two standardized test methods for measuring melting capacity, SHRP H-205.1 for solid deicers and SHRP H-205.2 for liquid deicers, but there have been concerns that these tests are not accurate. Researchers have developed alternative test methods, including the shaker test, the mechanical rocker test, and the ice cube titration test. This paper summarizes published data on measured melting capacity for sodium chloride (NaCl). The published data were compared with the calculated melting capacity of NaCl. The findings confirm that SHRP tests have low reproducibility and are not able to measure full melting capacity. The newer test methods measured closer to full melting capacity than the SHRP tests did. They also showed improved accuracy, although more data from the newer test methods are needed before conclusions can be drawn.

Phase equilibria in the sodium formate–potassium formate–water system below 0°c and the anti-icing properties of salt compositions

Phase equilibria in the sodium formate—potassium formate—water system below 0°C along the NaHCOO : KHCOO = 5 : 1, 4 : 1, 3 : 1, 2 : 1, and 1 : 1 w/w sections have been investigated, the onset temperatures of ice crystallization from the aqueous solutions have been determined, and ice melting polytherms have been constructed for each section. The ice-melting capacity of the formate mixtures at —5 to —10°C has been calculated.

Effect of Prewetting Brines on the Ice-Melting Rate of Salt at Very Cold Temperatures

At temperatures close to its eutectic, sodium chloride (NaCl) is shown to have substantial ice-melting capacity, but the ice-melting rate is very slow. The effects of magnesium chloride (MgCl2), NaCl, and mixed MgCl2-NaCl brines on the ice-melting rate of prewetted NaCl rock salt at temperatures close to the NaCl eutectic were measured. The solid salt component of a 50:50 mixture of salt and 26.0% MgCl2 brine melted ice 7.1 times faster than dry salt after 3 h, 3.5 times faster after 7 h, and 1.7 times faster after 24 h at an average temperature of −4.48F (−20.2°C). The solid salt component of a 50:50 mixture of salt and 23.3% NaCl brine melted ice 2.9 times faster than dry salt after 3 h, 2.0 times faster after 7 h, and 1.6 times faster after 24 h at the same temperatures. Ice-melting rates with mixed MgCl2-NaCl prewetting brines were intermediate between those of the straight NaCl and MgCl2 prewetting brines. Above a ratio of prewetting brine-to-salt high enough so that the ice was completely covered with brine, there was no significant increase in the ice-melting rate with increased prewetting brine application rate. Preliminary evidence suggests that a contribution to the rate enhancement caused by MgCl2 may be enhanced diffusion of NaCl from the dissolving salt crystals in the MgCl2 brines.

Anti-icing agents based on magnesium and sodium acetates and chlorides

Phase equilibria in sections of the Mg(CH3COO)2-NaCl-H2O system at 0 to −30°C have been investigated, and, based on the data obtained, new anti-icing agents (solid and liquid ones) are suggested. The ice melting capacity of these agents under equilibrium conditions has been determined. The liquid agent causes no damage to Portland cement concrete pavements. The corrosivity of this agent toward carbon steel St3 has been determined. The agent can be made considerably less corrosive by introducing a corrosion inhibitor. The agents can be prepared using mineral raw materials, namely, bischofite (MgCl2 · 6H2O) and halite (NaCl).

Evaluation of Ice-Melting Capacities of Deicing Chemicals

Abstract Common deicing chemicals include sodium chloride, magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, potassium formate, and corn or beet-based deicer solution. Liquid deicers are commonly used for pre-wetting road salt, sand or other solid deicers, or mixed with salt brine as liquid deicer. Although manufacturers provide performance data under specific conditions, a standardized test is very much needed. Samples of sodium chloride, magnesium chloride, calcium chloride, potassium acetate, and beet juice-based chemical deicers were selected for performance evaluation. The SHRP Ice-Melting Capacity Test has been used in many research projects, but the results do not always correlate well with field data. A simple and economical test has been developed to evaluate the ice-melting capacities of deicing chemicals using a martini shaker, which shows some potential to become a standardized test for ice-melting capacity evaluation. Field data was collected by the Nebraska Dept. of Roads using automatic vehicle location (AVL) and the maintenance decision support system (MDSS) installed on some plow trucks. The AVL takes roadway pictures from the cab and records vehicle location. The MDSS collects weather data from area weather stations. Although initial shaker test results correlate well with known deicer performance and limited field data provided by MDSS, further development work is necessary before the shaker test can be considered for official use.

Development of Standard Laboratory Testing Procedures to Evaluate the Performance of Deicers

Abstract This work aims at identifying and developing standard laboratory testing protocols that can be used to evaluate the performance of deicing chemicals, additives, and mixtures of these used on roadways and other transportation facilities. Several test methods were evaluated for the purpose of developing a promising test protocol, including a differential scanning calorimetry (DSC) thermogram test for liquid deicers, modified Strategic Highway Research Program (SHRP) ice melting test for solid and liquid deicers, modified SHRP ice penetration test for solid and liquid deicers, and a modified ice undercutting test developed by Minnesota Department of Transportation (DOT) for solid and liquid deicers. These tests shed light on the complexity and challenges in evaluating various deicers, especially the poor reliability inherent in conventional test methods. The DSC-based method was demonstrated to be very reproducible for each deicer at a given dilution ratio and cooling/heating rate, and thus may serve as a “fingerprint” tool for quality assurance of deicers. The DSC data also showed strong correlation with the modified SHRP ice melting test data, which holds the promise of establishing the DSC-based method for evaluating the performance of liquid deicers (both in terms of characteristic temperature and ice melting capacity). The modified SHRP ice melting test used in this study incorporates a control substance for reference and various indicators to determine acceptability of the data, as discussed in the paper.

Longevity of corrosion inhibitors and performance of liquid deicer products under field storage

This work investigated the longevity of inhibitors and the performance of corrosion-inhibited deicer products under two storage conditions. Three liquid deicers (MgCl2-based FreezGard, CaCl2-based CCB, and NaCl+GLT) were selected for the field storage monitoring and the key properties tested included the chloride and inhibitor concentrations, corrosion parameters (Ecorr and PCR), pH, electrical conductivity, and performance parameters (Tc and IMC30°F). The three liquid deicers investigated did not lose their quality over the 14 months of field storage, regardless of the storage condition (mixed or non-mixed). As such, it is not necessary to implement any mixing for the liquid deicer tanks during storage. It is however essential to mix the tanks immediately prior to the use of the liquid deicers, to ensure uniform composition. This study also revealed that the investigated corrosion inhibitors did not show side benefits in suppressing effective temperature or in providing ice melting capacity of their corr...