Search

Abstract Completion fluids play a vital role in well-related processes within the oil extraction industry. This article presents a comprehensive study of the properties and performance of various brine solutions as completion fluids for different well and reservoir conditions. Attributes examined include density, corrosion resistance, temperature stability, compatibility with formation fluids, clay swelling potential and influence on wettability. The research highlights the significance of selecting appropriate completion fluids to optimize well and reservoir operations. Zinc chloride emerges as an excellent option for high density applications, while sodium chloride and potassium formate solutions are ideal for extreme cold conditions. Potassium acetate outperforms calcium chloride and potassium chloride and has excellent pH stability. The compatibility of completion fluids with formation water has been observed to be excellent, with no sedimentation or emulsion formation. Potassium acetate also experiences minimal clay swelling, making it suitable for clay-rich formations. On the other hand, calcium chloride has a higher clay swelling than most of the brines tested, making it less suitable for sandstone formations with a higher clay content than these brines. The research evaluates the water-wetting abilities of completion fluids in carbonate and sandstone formations. Potassium chloride and zinc chloride have the most significant impact in carbonate formations, while potassium acetate and potassium formate excel in sandstone formations. This study provides a comprehensive understanding of completion fluids, facilitating informed decisions that maximize operational efficiency, protect reservoir integrity, and enhance hydrocarbon recovery. The appropriate selection of completion fluids should align with specific well and reservoir conditions, considering the priorities of the application.

Hydrazine complexes with formic acid, free formate ion, and a potassium formate complex 5DMSO · K+HCOO− formed in the system N2H4—HCOOH—K+HCOO−— DMSO were studied. The possibility for hydrazine formylation to occur was assessed. According to calculations, a [N2H6(HCOO)3]− complex is formed in the system in question. The calculated kinetic and thermodynamic characteristics suggest that hydrazine formylation can occur in this complex. The reaction is reversible; as a consequence, the reaction medium can contain both the [N2H6(HCOO)3]− complex and formylhydrazine. All calculations were carried out using the B2PLYP-D2/6-311+G**//B3LYP/6-31+G* approach with inclusion of solvation effects in terms of the IEFPCM continuum model with DMSO as solvent and with explicit inclusion of the nearest solvation shell of the potassium cation (five DMSO molecules). [ABSTRACT FROM AUTHOR]

Completion fluids play a vital role in well-related processes within the oil extraction industry. This article presents a comprehensive study of the properties and performance of various brine solutions as completion fluids for different well and reservoir conditions. Attributes examined include density, corrosion resistance, temperature stability, compatibility with formation fluids, clay swelling potential and influence on wettability. The research highlights the significance of selecting appropriate completion fluids to optimize well and reservoir operations. Zinc chloride emerges as an excellent option for high density applications, while sodium chloride and potassium formate solutions are ideal for extreme cold conditions. Potassium acetate outperforms calcium chloride and potassium chloride and has excellent pH stability. The compatibility of completion fluids with formation water has been observed to be excellent, with no sedimentation or emulsion formation. Potassium acetate also experiences minimal clay swelling, making it suitable for clay-rich formations. On the other hand, calcium chloride has a higher clay swelling than most of the brines tested, making it less suitable for sandstone formations with a higher clay content than these brines. The research evaluates the water-wetting abilities of completion fluids in carbonate and sandstone formations. Potassium chloride and zinc chloride have the most significant impact in carbonate formations, while potassium acetate and potassium formate excel in sandstone formations. This study provides a comprehensive understanding of completion fluids, facilitating informed decisions that maximize operational efficiency, protect reservoir integrity, and enhance hydrocarbon recovery. The appropriate selection of completion fluids should align with specific well and reservoir conditions, considering the priorities of the application. [ABSTRACT FROM AUTHOR]

Achievement of thermal comfort in air conditioning is a vital issue in the verge of global warming, where it is essential to provide a system that is less harmful to the environment, energy-efficient and economical. In this regard, dehumidification plays an important role in achieving thermal comfort of air conditioning system. Most of the dehumidification systems as of now require high energy and induce negative environmental impacts. Recently a vacuum membrane-based dehumidification has been considered for the alternative air-conditioning system. Development of efficient membranes for the dehumidification operation is indispensable for moisture removal. Typically, the membrane is constructed out of a fine and porous twilled Dutch weave stainless steel wire mesh serving as the support structure laminated with a film of active materials that serve to attract and isolate the moisture from the working air. In this work a combination of nanomaterial and hygroscopic polymer was adopted to improve the film functionality on the wire mesh. In particular, titanium dioxide (TiO2) is coated as intermediate layer on the wire mesh. Further, Polyvinyl alcohol (PVA) and various concentration of potassium formate (KCOOH) were used as the active additive material aiming to increase sensitivity of the membrane towards water vapor. The water vapor and air permeability tests were conducted to investigate the water vapor permeation and air selectivity of the membrane under various air conditions. Morphological and permeance analogy of the produced membrane showed that adding KCOOH enhanced hydrophilicity, which also increased water vapor permeability by 720%. [ABSTRACT FROM AUTHOR]

The performance of perovskite solar cells (PSCs) is negatively affected by iodine (I2) impurities generated from the oxidation of iodide ions in the perovskite precursor powder, solution, and perovskite films. In this study, the use of potassium formate (HCOOK) as a reductant to minimize the presence of detrimental I2 impurities is presented. It is demonstrated that HCOOK can effectively reduce I2 back to I− in the precursor solution as well as in the devices under external conditions. Furthermore, the introduced formate anion (HCOO−) and alkali metal cation (K+) can reduce the defect density within the perovskite film by modulating perovskite growth and passivating electronic defects, significantly prolonging the carrier lifetime and reducing the J–V hysteresis. Consequently, the maximum efficiency of the HCOOK‐doped planar n–i–p PSCs reaches 23.8%. After 1000 h of operation at maximum power point tracking under continuous 1 sun illumination, the corresponding encapsulated devices retain 94% of their initial efficiency. [ABSTRACT FROM AUTHOR]

Various internal and external defects present in the perovskite film are one of the main factors that cause low efficiency and stability, and in order to realize high-performance perovskite solar cells, it is necessary to develop a method to effectively suppress them. In this study, a heterofunctional dopants strategy was attempted to integrate the effect of alkali metal cations (Rb+ and K+) and formate anion (HCOO¯) through doping engineering with alkali-metal formates, i.e., rubidium formate (RbHCOO) and potassium formate (KHCOO). Inclusive physical and photoelectric analysis revealed that doping with a small amount of alkali-metal formate leads to crystal growth and reduction of grain boundaries, and further passivates or inhibits bulk and surface defects. As a result, the photogenerated charge recombination was reduced and the charge carrier transport was improved, leading to improved PSC performance. RbHCOO-doped inverted planar PSCs achieved a PCE of up to 20.41% with long-term stability. Our findings provide a way for producing high-quality perovskite films with low defect densities that are essential for realizing high-performance PSCs.

Use of de-icing agents is necessary in winter to maintain appropriate quality of road and airport surfaces. Formate or acetate de-icing agents are safer for aircraft and the environment than the commonly used sodium chloride, but may cause an alkali-silica reaction in concrete. The study investigated the influence of sodium formate and potassium formate on the occurrence of ASR (alkali-silica reaction) in mortars with granite aggregate. Accelerated mortar-bar tests at 80°C using various de-icing agents were performed and detailed studies of the SEM-EDS microstructure were carried out. [ABSTRACT FROM AUTHOR]

Large amount of montmorillonite is generally encountered when drilling in salt/gypsum-containing or shale formations. Montmorillonite, as a typical easily hydrated and swelling clay, when in contact with filtrates from water based drilling fluids, will cause borehole wall instability, stuck pipe, tight hole and borehole collapse etc. Formate water based drilling fluid containing potassium formate, a strongly inhibitive additive, is becoming an important water based mud for drilling complex formations. In laboratory studies, a molecular dynamics method was adopted to further reveal, from the molecular point of view, the mechanisms of potassium formate to inhibit the hydration of montmorillonite. The interaction of potassium formate and montmorillonite was calculated by establishing the models of the two. It was found from the studies that the ionized formate in the potassium formate solution mainly interacts with water molecules existed in between the montmorillonite layers and can form hydrogen bonds with the water molecules. The ionized potassium, on the other hand, is adsorbed on the surfaces of the montmorillonite particles, thereby reducing the zeta-potential of the montmorillonite particles by reacting with the surfaces of the particles. At a concentration that is above a certain level, the number of potassium ions adsorbed onto the surfaces of the montmorillonite particles reaches saturation, and the redundant potassium ions begin to diffuse into the spaces between two montmorillonite layers. Simulation experiments showed that low concentration potassium formate solution is beneficial to stabilizing the mechanical property of montmorillonite; as the concentration of potassium formate increases, it inhibits the diffusion of water molecules, and the mechanical property of the montmorillonite is deteriorated to some extent. When the concentration exceeds a certain level, the inhibitive capacity of potassium formate becomes stabilized, so does the mechanical property of the montmorillonite. The simulation results show that the optimum concentration of potassium formate in water based drilling fluids is 32.57% – 34.92%. [ABSTRACT FROM AUTHOR]

Open absorption heat pump (OAHP) system is more viable option to recover waste heat from moist gas as compared to the traditional condensation methods. This promising technology has great potential for latent heat recovery from moist gas, drying process in paper and other industrial heating applications. This study presents the process modelling and comparative analysis of OAHP system in Aspen Plus using two different solutions by adopting part regeneration technique. The promising potassium formate-water (HCOOK/H2O) which has lower causticity, lower costs and better crystallization characteristics is used as an alternative to the caustic lithium bromide-water (LiBr/H2O) solution in this study. Process model of the system is established in Aspen Plus and, the properties validity is confirmed with published experimental and Engineering Equation Solver (EES) library data. A detailed comparative parametric study is carried out to evaluate the effect of influencing parameters on coefficient of performance (COP), water recovery (φ) and heat recovery (ζ) efficiencies. The performance of OAHP system is found to be very similar using different concentrations as 2.13 COP value for 50% LiBr/H2O and 2.19 for 70% HCOOK/H2O solution over design conditions. Similarly, φ is found to be 0.701, 0.688 while ζ as 0.716 and 0.705 for both the absorbents. Moreover, the system's operational concentration range is 45-61.3% for LiBr/H2O and 55-82.1% for HCOOK/H2O at 135 °C regeneration heat input. Potassium formate solution having quite similar properties to the aqueous lithium bromide is also confirmed to have similar performance trends using 50% and 70% concentrations. [ABSTRACT FROM AUTHOR]

The formation and evolution of the corrosion scales on the super 13Cr stainless steel (SS) surface after exposure in a formate completion fluid with the presence of various aggressive substances was investigated. The results indicate that the formation of Fe3O4 covered the surface of super 13Cr SS as the inner layer accompanied with outer scattered FeS. The corrosion rate was below 0.07 mm/year after 120 h of exposure in the formate fluid at 180°C under N2 environments; the presence of aggressive substances such as sulfide and CO2 in the formate fluid promoted the proceeding of anodic dissolution in the early period, and the ingress of CO2 progressively increased the general corrosion rate to 1.7 mm/year. For CO2-containing conditions, the formation of FeCr2O4 and Cr(OH)3 was detected in the inner corrosion product layers, and the precipitation of “sheet”-shaped iron carbonate (FeCO3) was detected as the outer layer. The accumulation rate of corrosion products increases by two orders of magnitude with the ingress of CO2, corresponding to thicker corrosion products, but the dissolution rate is still three orders of magnitude higher than when CO2 was absent.

During the wintertime, concrete pavements experience harsh exposure conditions due to the presence of both the freezing–thawing and wetting–drying cycles. Airport concrete pavements are commonly de-iced using chloride-free organic salts such as potassium formate or potassium acetate. However, these materials contain alkali ions which can have harmful effects on both the cement matrix and the aggregate. Specifically, there is an increased risk of occurrence of the alkali–silica reaction (ASR). The goal of this research was to estimate the influence of potassium formate on the potential of causing alkali–silica reaction in aggregates with different categories of reactivity (R0, R1, R2). The accelerated mortar bar test and its modification (which involves replacing sodium hydroxide solution with a potassium formate solution) were used. Detailed SEM-EDS examinations were performed to confirm the presence of alkali–silica reaction and to analyze the influence of potassium formate on the microstructure of mortar.

Air conditioning using a liquid desiccant (LD) is an energy-efficient air purification and cooling system. However, high energy is required to concentrate or regenerate the LD. This study aimed to investigate the characteristics of membrane fouling in more detail and determine control strategies for LD concentrating using membrane distillation (MD). Two different LDs—lithium chloride (LiCl) and potassium formate (HCOOK)—were used. Because LDs require high concentrations by nature (i.e., 40 wt% for LiCl and 70 wt% for HCOOK), the concentration was started from half of those concentrations. This resulted in a flux decline with severe membrane fouling during the concentration using MD. Different membrane fouling mechanisms were also observed, depending on the LD type. Three different physical membrane fouling control methods, including water flushing (WF), air backwashing (AB), and membrane spacer (SP), were introduced. Results showed that WF was the most effective. Both AB and SP showed a marginal change to no cleaning; however, an initial flux with SP was about 1.5 times higher than no cleaning. Therefore, WF combined with the SP could maintain a high flux and a low fouling propensity in the treatment of a high-concentration solution using MD.

Liquid desiccant dehumidification is promising as it could be driven by renewable energy. In the present study, it newly investigated the dehumidification characteristics of KCOOH solution in an internally cooled dehumidifier. To select suitable concentration range, the vapor pressure of KCOOH solution with different solution concentration and temperature was measured with static method firstly. Then comparative experimental study was conducted to identify the dehumidification performance of KCOOH and LiCl solution under different solution and air flow rate, temperature and air humidity. Experimental results indicated that 70.3% KCOOH solution had almost the same vapor pressure as 35% LiCl solution. Under the same experimental conditions, the absolute moisture removal of 70.3% KCOOH solution was slightly higher than that of 35% LiCl solution as a result of the increased wetting area. It was found that the mass transfer coefficients of the two liquid desiccants were almost the same. An empirical correlation of S h number was obtained to predict the mass transfer coefficient of KCOOH solution for dehumidification with a mean absolute relative deviation of 7.81%. • 70.3% KCOOH had almost the same vapor pressure as 35% LiCl. • Absolute moisture removal of 70.3% KCOOH was higher than that of 35% LiCl. • Wetting ratio is higher for KCOOH than LiCl. • A correlation of S h number was fitted for KCOOH dehumidification. [ABSTRACT FROM AUTHOR]

In recent years, microplastics (MPs) contamination has been emphasized as one of the most global ecological problems. Bottom sediments were identified as one of the major sinks of MPs, while river-lake systems - as the main transport routs of MPs into the coastal seas and the World Ocean. Thus, the MPs determination in freshwater sediments is an important task for identifying sedimentation processes and contamination sources. Density separation is commonly used to extract anthropogenic particles from bottom sediments. The proposed method is dedicated to determining the abundance of MPs in freshwater organic-rich sediments. Repeated wet peroxide oxidation was applied to digest organic matter that can hamper the microplastic determination in a sample. Potassium formate with a density 1.5 g/mL was used as a separation solution. This method is intended to identify various types of MPs (fibers, films, fragments and beads) ranging in size from 0.174 to 5 mm. The effectiveness of the MPs extraction with potassium formate was 98.0 ± 2 % (р = 0.05; n = 16), while the extraction of MPs when analyzed under a microscope was 92.0 ± 4% (р = 0.05; n = 20).

Microplastics (MPs) are considered an important stratigraphic indicator, or ‘technofossils’, of the Anthropocene. Research on MP abundance in the environment has gained much attention but the lack of a standardized procedure has hindered the comparability of the results. The development of an effective and efficient method of MP extraction from the matrix is crucial for the proper identification and quantifying analysis of MPs in environmental samples. The procedures of density separation used currently have various limitations: high cost of reagents, limited solution density range, hazardous reagents, or a combination of the above. In this research, a procedure based on density separation with the use of potassium formate water solution (H2O/KCOOH) in controlled conditions was performed. Experimental sediment mixtures, spiked with polyethylene (PE), polystyrene (PS), polyurethane (PUR) and polyethylene terephthalate (PET) particles were prepared and an extraction procedure was tested in the context of a weight-based quantitative analysis of MPs. This article discusses the effectiveness and safety of the method. It additionally provides new information on the interactions between MP particles and the mineral matter of the sediment. Results were acquired with the use of instrumental methods, namely thermogravimetry (TG), Fourier Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron microscopy and Energy Dispersive spectrometry (SEM/EDS), as well as X-ray fluorescence (XRF) analysis.

Bubble pressures of the Potassium formate – Water solution (HCOOK + H2O) were measured in the temperature range 313.15–453.15 K with the mass fraction of HCOOK from 0.2–0.75. The experimental data were correlated with electrolyte-NRTL model and compared with reported empirical model. This work shall be helpful for the design and evaluation of absorption refrigeration system using Potassium formate – Water as a working fluid pair. [ABSTRACT FROM AUTHOR]

Xanthan gum solutions have gained increasing interest for their use as environmentally friendly chemicals in the oil industry. Xanthan is compatible with most concentrate brines used for controlling formation damage and fluid loss. Particularly, formate brines reinforce the ordered structure of the biopolymer in solution, gel strength, and the specific gravity of the resulting fluid. In this paper, we studied the effect of thermal aging on the rheological behavior of xanthan solutions as a function of the concentration in potassium formate. Ionic strength below a threshold concentration does not prevent the degradation of the structure of xanthan after being submitted to aging at 165 °C. Aged solutions show an important loss of strength in their mechanical properties, lower pH, and higher content in furfural and hydroxymethylfurfural. Highly concentrated formate brines are necessary to maintain the strength of the rheological properties after exposure to high-temperature environments.

• A hybrid heat recovery system based on liquid desiccant is proposed for boilers. • System thermal efficiency can reach 104.0% when return water temperature is 60 °C. • A better inlet temperature and flowrate of the desiccant solution are recommended. • The formation of white smoke is avoided due to lower flue gas relative humidity. In district heating, conventional flue gas heat recovery systems do not perform well anymore when the return water temperature is high. In this paper, a hybrid heat recovery system based on vapor compression refrigeration and liquid desiccant dehumidification is then proposed, with proper refrigerants and desiccants recommended. A simulation model of this system is established and a typical case is studied based on the model with a return water temperature of 60 °C. Then, an equivalent thermal efficiency is introduced to evaluate the system performance. Parametric analyses are conducted by changing the liquid-gas flowrate ratio and the inlet solution temperature in the second stage of the absorber in the system. According to the parametric analyses, a liquid-gas mass flowrate ratio of 3.2–3.4 and an inlet solution temperature of 45 °C are recommended as the best working conditions considering the economic and ecological effects. Under these conditions, the equivalent thermal efficiency of a boiler can be increased from 90% to 104%. For a boiler with a rated heating capacity of 7 MW, about CNY 236,000 (USD 34,000) can be saved per month. Besides, the flue gas is finally discharged at a relative humidity of only 33%. The formation of white smoke can thus be avoided and the contaminant attachment in the atmosphere around can be alleviated. The proposed system is efficient and environmentally friendly and the simulation results can offer references to real applications under variable working conditions. [ABSTRACT FROM AUTHOR]

The heat and mass transfer process of a novel cross-flow hollow fiber integrated liquid desiccant dehumidification system is analyzed numerically. Compared with other porous media or packing towers in dehumidification applications, hollow fibre membranes have significant advantages including low weight, corrosion resistance and no liquid droplet carryover. A novel air-KCOOH cross-flow dehumidification system was designed and manufactured, with 5500 hollow fibres formed into a circular module. The variations of the dehumidification effectiveness and moisture removal rates were studied numerically and validated against experimental results under the incoming air mass flow rates of 0.08–0.26 kg/s and relative humidity from 55% to 75%. The dehumidification performance comparisons for the proposed system using CaCl 2 , LiCl and KCOOH as the desiccants have been conducted. The results demonstrated that under the same m*(ratio between solution mass flow rate to the air mass flow rate), the proposed system using 62% KCOOH could achieve approximately the same latent effectiveness compared with 40% CaCl 2 and 32% LiCl, with at least 3.1% sensible effectiveness improvement. Therefore, it could be concluded that the proposed system using KCOOH as desiccant could be more applicable for dehumidification purpose compared with other systems using conventional liquid desiccants. [ABSTRACT FROM AUTHOR]

Highlights • The vapor pressure and density of KCOOH solution were measured and fitted in formulas. • Heat capacity of KCOOH solution was also fitted with the MARD of 0.15%. • Models of mass transfer process concerning film shrinkage were developed. • The predicted falling film shape agreed well with experimental measurements. • The predicated performance was also in line with the experimental data. Abstract Compared with the extensive attention drawn by salt solutions, the promising potassium formate (KCOOH) solution which has smaller causticity and lower price receives little attention in the field of liquid desiccant cooling system (LDCS). Consequently, the present paper studied both the thermal properties and mass transfer performance of KCOOH solution for its practical engineering application. The vapor pressure and density of KCOOH solution under different concentrations and temperatures were measured and then fitted in the form of polynomials with the mean absolute relative deviation (MARD) of 0.06% and 0.551% respectively. Referring to the data in the existing literature, the heat capacity of KCOOH solution was also fitted with the MARD of 0.15%. Mathematical models of dehumidification/regeneration with the film shrinkage on the plate dehumidifier/regenerator were developed and validated by the experimental data. Results showed that the wetting ratio predicted by the model matched well with the measured one with the relative difference of 3.4%. Besides, the dehumidification/regeneration performance obtained by the model in terms of absolute moisture change was also in line with the experimental ones with the MARD of 6.05%/4.2%. In summary, the correlations of KCOOH solution thermal properties, mathematical model, and experimental results were valuable for the engineering application of KCOOH solution in LDCS. [ABSTRACT FROM AUTHOR]

Highlights • This paper presents equilibrium vapour pressure data for H 2 O–KCOOH desiccant. • This data is compared with a referenced chemical engineering property database. • A best-fitting regression model is reported: the MAPE is 1.1%. • H 2 O/KCOOH seems to be very promising as '' desiccant of the future ''. Abstract This paper presents the measurement of the equilibrium vapour pressure of H 2 O/KCOOH solution with a concentration in salt from 60 to 80% in the temperature range from 5 to 75 °C typical for desiccant application. The experimental measurements were performed in a VLE apparatus instrumented with a pressure gauge having a maximum uncertainty (k = 2) within ±35 Pa and a platinum resistance thermometer having a maximum uncertainty (k = 2) within ±0.05 K. A set of 40 experimental data points on H 2 O/KCOOH equilibrium vapour pressure was fully reported and compared with the unique other set of experimental data (Beyer and Steiger, 2010) available in the open literature and also with the estimation of a referenced chemical engineering property database (Aspen Plus®): a reasonable agreement was found in both the cases. A best-fitting regression model based on present set of data was also reported: the mean absolute percentage deviation between experimental and calculated data is 1.1%. [ABSTRACT FROM AUTHOR]

This study presents an Artificial Neural Network (ANN) model for predicting the dynamic viscosity of H 2 O/KCOOH (potassium formate) solution. The model accounts for the effect of temperature and concentration in salt and it covers the concentrations typical for brine (0–50%) and desiccant (60–80%) applications, including also pure water. The model shows a fair agreement in predicting experimental data: the mean absolute percentage error (MAPE) is 0.92%. The characteristic parameters of the ANN model are fully reported in the paper. [ABSTRACT FROM AUTHOR]

[Display omitted] • A passive humidity pump system is proposed for moisture transfer between two regions. • It consists of a passively-cooled thermosyphon-driven liquid desiccant membrane loop. • Potassium formate is used to allow effective absorption at elevated temperatures. • Parametric study is carried out to assess the system under various air conditions. • The system was able to pump the air humidity even against its natural flow direction. Indoor humidity management is one of the most challenging aspects of the control of indoor environment and is energy intensive, especially in hot and humid climates. A promising approach is the removal of the water vapor from the room using hygroscopic materials, otherwise known as desiccants. Desiccant cycles are thermally driven but require a heat sink and electricity-driven mechanical parts for desiccant circulation. Accordingly, this work proposes a thermosyphon-driven membrane-based liquid desiccant loop for sustainable humidity pumping between two areas at different humidity conditions. Mathematical models were developed for the different system subcomponents, which were validated with published data and in-house experiments. The models were used in a parametric study to determine the influence of the design and operation parameters on the system performance under different air conditions surrounding its various sections. It was found that the system was able to pump the air moisture from high to low and low to high humidity areas. Four cases were considered with outdoor conditions raging from moderate and hot and humid to semi-arid climates. The latent load removal density per unit area of the exposed membrane varied between 4 W/m2 to 35 W/m2 over the entire range of considered cases at required heat inputs varying between 150 W and 570 W respectively. The heat input increased with the channel height and the air humidity surrounding both system sides. The added sensible load depended on the heat sink temperature and was more than 65 % lower than removed latent load in most considered cases. [ABSTRACT FROM AUTHOR]

This paper aims to evaluate the application of liquid desiccant air conditioning technology in the development of efficient and effective tri-generation/waste-heat-driven system applications, in particular with regard to solid oxide fuel cell (SOFC) technology. Using operational thermal input values typical of an SOFC combined heat and power (CHP) system, the paper's evaluation validates the concept of integrating SOFC and liquid desiccant air conditioning technology into an efficient and effective first-of-its-kind tri-generation system. This is due to good dehumidification capacity and effective regeneration of a potassium formate solution at a 0.65-0.7 solution mass concentration. Conclusions of the paper's evaluation include: (1) effective instantaneous balancing of the dehumidifier and regenerator across a range of environmental and operational values, (2) operation of the dehumidifier is dictated, to some degree by the available thermal energy (CHP prime mover, process heat), (3) encouraging thermal COP values, for a system of this scale, in the range of 0.4-0.66 are achievable with a low-grade thermal input (45-60°C) typical of an SOFC CHP system and (4) potential for non-synchronous operation in a tri-generation system context, bringing about improvements to peak cooling output and total system efficiency. The compact nature and effective use of low-grade thermal energy means the liquid desiccant air conditioning system demonstrates significant potential for integration with other CHP prime mover technologies such as internal combustion engine or any (waste) heat source with a similar thermal quality/quantity. A future paper by the authors will present a novel SOFC liquid desiccant tri-generation system. [ABSTRACT FROM AUTHOR]

The present study intended to study the dehumidification performance of KCOOH solution both experimentally and numerically. The heat and mass transfer model for internal cooling dehumidifier was built. The influences of different parameters on dehumidification performance were identified by experiments. Results indicated that the air temperature and solution has negligible influence on dehumidification performance. However, the air humidity and solution temperature have significant influence on dehumidification due to its close relationship with mass transfer driving force. The proposed model can simulate the dehumidification performance in terms of absolute moisture change well with the MARD of 6.05%.

Formate-based fluids has been successfully used in over hunders HPHT well operations since they introduced in field practice. They have many advantages when compared with conventional HPHT drilling and completion fluids such as: minimal formation damage, maintenance of additve properties at high temperatures, reduced hydraulic flow resistance, low potential for differential sticking, naturally lubricating, very low corrosion rates, biodegradable and pose little risk to the environment etc. Formate-based fluids can be applied during deep slim hole drilling, shale drilling, reservoir drilling, salt and gas hydrate formations drilling. The laboratory research was carried out to evaluate the rheological behavior of formate-based fluids as a function of temperature. Formate-based fluids were formulated using potassium formate brine, xanthan polymer, PAC, starch and calcium carbonate. Experimental results show that potassium formate improves the thermal stability of polymers.

This paper presents the measurement of the thermal conductivity and the dynamic viscosity of H 2 O/KCOOH (potassium formate) desiccant with a salt concentration from 60 to 80% in the temperature range 1–80 °C. The thermal conductivity measurement gives evidence of a great sensitivity to salt concentration and lower sensitivity to temperature: H 2 O/KCOOH desiccant shows a thermal conductivity from 23 to 33% lower than water at the same temperature. H 2 O/KCOOH desiccant exhibits a Newtonian behaviour in all the investigated ranges of temperature and concentration. The relative viscosity shows a great sensitivity to salt concentration and weak or no sensitivity to temperature up to a solution concentration of salt around 70%. For higher solution concentration of salt (75 and 80%) the relative viscosity shows a great sensitivity also to temperature. H 2 O/KCOOH desiccant presents a dynamic viscosity from 4 to 30 times higher than water at the same temperature. [ABSTRACT FROM AUTHOR]

To date, the application of liquid desiccant air conditioning systems in built environment applications, particularly small scale, has been limited. This is primarily due to large system size and complexity, issues of desiccant solution leakage and carry-over and equipment corrosion. As a result, a novel integrated desiccant air conditioning system (IDCS) has been developed. The system combines the regenerator, dehumidifier and evaporative inter-cooler into a single membrane based heat and mass exchanger. This paper presents an evaluation, based on experimental data, of the novel IDCS operating with a potassium formate (CHKO 2 ) desiccant working fluid. A range of tests have been completed to characterise the performance of the dehumidifier, regenerator and complete IDCS. Cooling output in the range of 570 to 1362 W and dehumidifier effectiveness in the range of 30 to 47% are presented. An issue encountered has been an imbalance between moisture removal rate in the dehumidifier and moisture addition rate in the regenerator. As a result, an adjusted thermal COP (COP th,adj ) value has been calculated. COP th,adj values of 1.26 have been achieved with an average of 0.72. Electrical COP (COP el ) values of 3.67 have been achieved with an average of 2.5. The work demonstrates that the novel IDCS concept is viable and has provided progress to the field of liquid desiccant air conditioning technology for building applications. Further work is required in order to address the main issue of mass imbalance between the dehumidifier and regenerator. [ABSTRACT FROM AUTHOR]