Vapor Products Research Articles

Application of dividing wall column in azeotropic distillation with intermediate boiling-point heteroazeotrope: Simulation and optimization

Dividing wall column (DWC), as a proven process intensification technology, has been used widely in separation of ideal multi-components, and some azeotrope systems. For heterogeneous azeotrope with the potential possibility of crossing distillation boundary by liquid-liquid splitting, it is advantageous to integrate liquid-liquid decanter with distillation column, especially with DWC to further simplify flowsheets and reduce energy consumption. In this work, existing heterogeneous azeotrope separation processes are described, and an innovative DWC-based process (MHADWC) is proposed for intermediate boiling-point heteroazeotropic systems. Then an industrial case of MIPK system, is used to evaluate mentioned configurations by rigorous simulation and optimization. These configurations are compared and analyzed in detail on energy consumption, exergy analysis and equipment invest. The results show that, from the perspective of process energy consumption, MHADWC process has the most advantages, because it saves 37% of energy consumption; if both equipment costs and exergy recovery are taken into account, HADWC2 has a higher thermodynamic efficiency (43.5%) at its TAC and can be used as a preferred target. And in this work, purification of an intermediate boiling-point heteroazeotrope is the main difference of these processes compared with the well-known heterogeneous azeotropic distillation process where the top vapor product is the lowest boiling point of the ternary system.

Full cattail leaf-based solar evaporator with square water transport channels for cost-effective solar vapor production

Full cattail leaf-based solar evaporator with square water transport channels for cost-effective solar vapor production

Performance Assessment of Direct Vapor Generation Solar Organic Rankine Cycle System Coupled with Heat Storage

Phase change materials employed as thermal energy storage can aid in maximizing the use of stored solar energy. The current research examined the impact of three kinds of phase change materials (PCMs) on the dynamic performance of a solar organic Rankine cycle (ORC) system based on a direct vapor production. A number of evacuated flat plate collectors, a condenser, an expander, and an organic fluid pump make up this system. The thermodynamic cycle model of the direct vapor generation (DVG) solar ORC system was combined with the finite difference model of a phase change material heat storage tank created in MATLAB. The effect of PCMs (Organic, Inorganic and Eutectic PCMs) on the collector, ORC, and system efficiency, net power output, PCM temperature, and heat stored was studied weekly, monthly, and annually. Among the selected PCMs, Mg(NO3)2.6H2O had the highest system efficiency at 9.34%; KNO3-NaNO2 had the highest net power output at 33.80 kW; and MgCl2.6H2O stored the maximum energy of 20.18 MJ annually. Under the given operational and boundary conditions, the spring and fall were preferable to the summer and winter months for storing heat from phase change materials.

Design and fabrication of a multi-tubular fixed bed reactor for acetone production as a pilot plant model for chemical engineering training in developing nations

In this work, the design and fabrication of a pilot-scale multi-tubular fixed bed reactor have been carried out with the aid of computational software (MATLAB R2010b), aiming to process 6.5 L/h of isopropanol to acetone using non-adiabatic thermal conditions. The reactor fabricated would serve as a demonstration rig to enhance research practice, teaching, and learning processes in Advanced Reactor Analysis. The acetone production studied involves four stages, which are simultaneous vaporization and dehydrogenation, condensation, and storage. In the simultaneous vaporization and dehydrogenation, isopropanol is heated to 473 K indirectly to change the phase of raw material from liquid to vapor. In comparison, isopropanol is dehydrogenated to be acetone and hydrogen with 50 % conversion using Cu/SiO2 composite as a catalyst in the multi-tubular fixed bed reactor at 473 K and 1 bar. Condensation occurs when an ice bath cools down the vapor product to liquid. Hence, the condensed product is tested for acetone, and the overall cost analysis for the whole process iscalculated. The design can be a model for other chemical engineering schools to fabricate a locally made reactorfor the training and re-training of chemical engineers, especially in developing nations.

Deconvolution of Systemic Pharmacokinetics Predicts Inhaled Aerosol Dosimetry of Nicotine

Absorption of inhaled compounds can occur from multiple sites based on upper and lower respiratory tract deposition, and clearance mechanisms leading to differential local and systemic pharmacokinetics. Deriving inhaled aerosol dosimetry and local tissue concentrations for nose-only exposure in rodents and inhaled products in humans is challenging. In this study we use inhaled nicotine as an example to identify regional respiratory tract deposition, absorption fractions, and their contribution toward systemic pharmacokinetics in rodents and humans. A physiologically based pharmacokinetic (PBPK) model was constructed to describe the disposition of nicotine and its major metabolite, cotinine. The model description for the lungs was simplified to include an upper respiratory tract region with active mucociliary clearance and a lower respiratory tract region. The PBPK model parameters such as rate of oral absorption, metabolism and clearance were fitted to the published nicotine and cotinine plasma concentrations post systemic administration and oral dosing. The fractional deposition of inhaled aerosol in the upper and lower respiratory tract regions was estimated by fitting the plasma concentrations. The model predicted upper respiratory tract deposition was 63.9% for nose-only exposure to nicotine containing nebulized aqueous aerosol in rats and 60.2% for orally inhaled electronic vapor product in humans. A marked absorption of nicotine from the upper respiratory tract and the gastrointestinal tract for inhaled aqueous aerosol contributed to the differential systemic pharmacokinetics in rats and humans. The PBPK model derived dosimetry shows that the current aerosol dosimetry models with their posteriori application using independent aerosol physicochemical characterization to predict aerosol deposition are insufficient and will need to consider complex interplay of inhaled aerosol evolutionary process. While the study highlights the needs for future research, it provides a preliminary framework for interpreting pharmacokinetics of inhaled aerosols to facilitate the analysis of in vivo exposure-responses for pharmacological and toxicological assessments.

Evaluation of the effects of interfacial tension forces in homogenous equilibrium mixture modeling of a cavitation flow of liquefied natural gas inside a Laval nozzle

Achieving the robust performance in turbomachinery equipments including the modern liquefied natural gas (LNG) fuel pumps, is highly dependent on prediction of cavitating patterns and control of consequent cavitation damages. In most studies to date of cryogenic cavitation, effects of vapor-liquid interfacial tension on the onset and development of transient cryogenic cavitation have not been addressed sufficiently. This is of more interest when it comes to numerical homogenous equilibrium mixture (HEM) modeling of cavitation where vapor fraction field is calculated through appropriate weighting functions, as opposed to that in transport-equation –based modeling, known as TEM approach, where separate transport equation is introduced for calculation of vapor phase fraction. In the present work, a HEM-based cryogenic cavitation solver is employed to examine the interfacial tension effects on the phase-change behavior of LNG inside a Laval nozzle. Based on the theoretical considerations and comparison of the results with available literature data, it is concluded that the presence of interfacial tension forces in the in-nozzle cavitation LNG flow can potentially stabilize cavitating patterns through modifying the local phase-change incidents. The net LNG vapor production in the nozzle is however observed not to be largely affected by the interfacial tensions, suggesting the pre-dominance of temperature-dependent inertia and advective forces in modulating LNG phase-change processes. Counting the calculations of interfacial tension forces in the cavitation solver is also found to improve accuracy of the modeling against the experimental data.

Comprehensive Validation and Calibration of MODIS PWV over Mainland China

Although ground-based precipitable water vapor (PWV) can be obtained with a high temporal resolution and spatial resolution of tens of kilometers in an urban area using Global Navigation Satellite System (GNSS) observation, it remains fairly sparse in the vast regions over Mainland China. Satellite-derived PWV has a high spatial resolution, thereby enabling the accurate investigation of regional climate change. However, understanding the quality of satellite-derived PWV products is a prerequisite before use, which has become the focus of this study. PWV products, namely, MOD05_L2 and MYD05_L2, over the entirety of Mainland China derived from MODerate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellites are validated over the period 2000–2017 using multiple sources, including GNSS, radiosonde, AErosol RObotic NETwork (AERONET), and European Center for Medium-Range Weather Forecasts ERA-Interim (ECMWF). The accuracy of MODIS PWV products is less than 4.3 mm over the entirety of Mainland China; however, it varies in four areas of South China (SC), North China (NC), Northwest China (NWC), and Tibetan Plateau (TP), separately with values ranging from 3 mm to 6 mm. A linear fit model is applied to calibrate the MODIS PWV products, and the accuracies of the corrected PWV from MODIS infrared (IR) and near-infrared (NIR) products have been improved by approximately 7.5% and 50.6%, respectively. The MODIS PWV is compared and calibrated in the four areas, and the improved accuracies vary widely. The root mean square error (RMSE) of IR PWV is approximately less than 4 mm over China except for the SC area with a value of approximately 5.3 mm after calibration, whereas the values of NIR PWV are approximately 2 mm over the entirety of Mainland China, except for the TP area, with a value of approximately 2.6 mm. The MODIS NIR PWV performs better than that of IR PWV data in most areas of Mainland China regardless of whether with calibration. The validation and calibration of MODIS water vapor products over Mainland China also indicate their capability to investigate the seasonal and annual variations as well as long-term trend changes in water vapor in China.

Wasteless technology of coal gasification for heat and chemical production

Coal is a conventional source of energy, but its use has recently been restricted because of the environmental standards. Coal is a high-value source for the production of chemicals such as hydrogen, ammonia, methanol, carbamide, etc. The chemicals are produced from synthesis gas in the course of coal gasification. The value of coal as a source for the chemical production also lies in the ampleness of its reserves worldwide while oil and gas reservoirs are available not in all countries. Accordingly, the effective use of coal can contribute to the development of many branches of the chemical industry. The wasteless technologies of coal gasification for the production of heat, synthesis gas, reducing gas for the metallurgy needs and pure hydrogen are described. In these technologies, prior to gasification, thermal decomposition of coal is carried out in a reactor under temperatures up to 700 °C, and the volatile and resinous matters separated from carbon under temperatures of 300–550 °C, after cooling, are used in conformity with their material constitution. The coal gasification flowcharts function in a closed mode, where flows of heated gases first heat coal for the recovery of the associate components of carbon, some heat of the heated gases goes to the production of vapor for the steam gasification of carbon, and the residual heat of gases, up to absorption of СО2 by solutions of alkalis, is used to produce hot water, which reduces external consumption of heat in coal gasification. The proposed methods of coal gasification are low-cost as the by-produced substances and heat of different heated materials are utilized. Moreover, air emissions are absent, thus, the production is ecofriendly and green.

Testing of a Low-Cost Dry Cell Prototype for Oxyhydrogen Production

This work aims to study the production of oxyhydrogen gas by a small low-cost prototype consisting of six dry cells. Firstly, a molecular composition study of the gas was carried out, presenting concentrations of 67% H2 and 28% O2. The deviation from the stoichiometric yield is discussed to be caused by water vapor production and/or oxygen dissolution in the liquid phase. Secondly, an efficiency study was done, considering the ratio between the reversible voltage of an electrolytic cell and the voltage applied to the dry cell by an external power source. Different working conditions (electrolyte concentration, 3% (w/w) of KHO and 20% (w/w) of KHO) have been tested to analyze their effect on the efficiency of the system. The results show that a lower electrolyte concentration increases the applied cell voltage, and so the necessary power input for gas production to occur, resulting in lower cell efficiency. Overall, the efficiencies are below 69.8 ± 0.6% for the studied electrolyte concentrations and approach approximately the same value around 50% for higher powers.

Study on root hump formation mechanism in full penetration laser welding with backing gas for aluminum alloy

The dynamic behavior of molten pool in full penetration laser welding (FPLW) with backing gas or without backing gas for aluminum alloy was observed. It is found that the backing gas can greatly improve the root hump formation. A transient and multi-phase 3D numerical model considering the metallic vapor ejection process was developed to explain this phenomenon, in which an evaporation and condensation model was established to simulate the production of metallic vapor. Based on the proposed model, the metallic vapor ejection, periodic keyhole variation profiles and molten pool evolution were presented, which indicated that the flow pattern of melt in the molten pool was deeply affected by the vapor ejection pattern. The ejection velocity of vapor is 45–70 m s −1 . The high-speed vapor makes the melt flow (MF) velocity within 1 mm of the keyhole wall change from 5.5 m s −1 to 0.2 m s −1 . The high velocity gradient near the keyhole is the main reason to form an invert cone-shaped sagging under the keyhole and some globular spatters near the keyhole outlet. The surface tension plays an important role to shorten the invert cone-shaped sagging and improves root hump formation. Alumina film formed on the back surface of molten pool can worsen the root hump formation due to the lack of surface tension. • An innovative transient and multi-phase 3D numerical model considered the metallic vapor ejection process was developed to simulate the root hump formation process in full penetration laser welding of aluminum alloy. • The flow pattern of melt in the molten pool evolution was presented in the full penetration laser welding with backing gas. • Proposing that the high-speed metallic vapor results in a significant velocity gradient near the keyhole wall, which is the main reason to form an invert cone-shaped sagging under the keyhole. • Proposing that the surface tension plays an important role to shorten the invert cone-shaped sagging and backing gas is helpful for improving the formation of root hump.

The Influence of Brand Equity, Price and Service Quality on Vapor Product Purchase Decisions

This study aims to determine, explain and analyze the effect of Brand Equity, Price, and Service Quality on Vapor Product Purchase Decisions on Vapeboss Sidoarjo. This research is based on a fact in the company that if the brand equity in Vapeboss Sidoarjo is high, it will add value to consumers, as well as the price at Vapeboss Sidoarjo which is affordable so that it can compete with other stores. However, this is also balanced with the quality of service at the Vapeboss Sidoarjo store so that consumers continue to survive and use products at Vapeboss Sidoarjo. This study uses quantitative methods, data collection techniques using questionnaires, distributed to 100 respondents who have used Vapeboss Sidoarjo products. The data analysis technique used in this study is multiple linear regression using SPSS (Statistical Program for Social Science) version 25. The results of this study prove that brand equity variables affect consumer decisions, price variables affect consumer decisions, service quality affects on consumer decisions, and brand equity, price and service quality variables have a simultaneous effect on purchasing decisions for vapor products at Vapeboss Sidoarjo.

Low-Cost Air Purifier Prototype Using a Ventilating Fan and Pump Against Haze Pollution

This study aimed to focus on the design and development of low-cost do-it-yourself (DIY) air purifiers, using a ventilating fan, air pump, water pump, and an ultrasonic generator that can be used during the haze pollution. Six types of household air purifiers were fabricated. The amount of particulate matter (PM) and carbon dioxide (CO2) levels were recorded at 0, 10, 20, 30, and 60 min (min), then, repeated 3 times. After 10 min of the 3rd experiment of each study, the last measurement of air pollution would be recorded. The results showed at 60 min, the high-efficiency particulate air (HEPA) filter and electrostatic fiber was the best technique regarding reduction of PM and CO2 levels. The highest PM reduction rate had occurred at 30 min using an air pump procedure (99.330 to 100%). The CO2 levels of all experiments had fluctuated at different times. After 10 min of a closed machine, PM levels of all air purifier systems were decreased, except HEPA filter and electrostatic fiber types. In conclusion, the best method for reducing particulate matter and cost without taking humidity into account is an air pump technique, whereas the HEPA filter and electrostatic fiber method is the best choice for lowering PM levels without increasing humidity and vapor production.

Predicting spatial and temporal changes in surface urban heat islands using multi-temporal satellite imagery: A case study of Tehran metropolis

Nowadays, predicting spatial and temporal changes of surface urban heat islands (SUHIs) is both a demanding challenge and a subject of interest for researchers working on urban thermal environments. This study aimed to predict the spatial-temporal changes of SUHI in Tehran city. The research data consisted of Landsat multi-temporal images, MODIS-derived water vapor and land surface temperature (LST) products, as well as climatic data. The cellular automata (CA)-Markov model was used for predicting the spatial and temporal land cover changes. Afterward, based on the statistical and spatial information of the impact of land cover changes on LST changes, maps of the LST and SUHII were procured for future years. The results showed that the area of built-up lands increased by 88% from 1985 to 2019. The built-up lands area is expected to increase to 446.3, 463.9, and 480.1 km2 by 2026, 2032, and 2038, respectively. The mean LST of Tehran city in 1985, 1992, 2000, 2009, and 2019 was 36.45, 41.95, 43.15, 44.95, and 47.25 °C, respectively. By 2026, 2032, and 2038, the mean LST may reach 48.65, 49.95, and 51.15 °C, respectively. Analysis of the SUHI ratio index in Tehran showed an increase from 0.01 in 1985 to 0.34 in 2019, and is expected to reach 0.38, 0.45, and 0.51 by 2026, 2032, and 2038, respectively.

Group Combustion of Dispersed Spherical Core–Shell Nanothermite Particles

The group combustion characteristics of core–shell nanothermite particles differ from other dispersed solid or liquid fuels. In a core–shell structure, each discrete nanothermite particle can undergo an exothermic reaction as the oxygen atoms in the metal oxide shell undergo a solid state diffusion to oxidize the metal core. This feature allows the spherical core–shell nanothermites to react in the absence of gaseous oxygen, thus modifying their group combustion characteristics compared to char or liquid fuels. Using a number of simplifying assumptions, a theoretical framework was established—based on existing group combustion theory—to examine the characteristics of mass and heat diffusion in nanothermite combustion. First, a model for the quasi-steady state single-particle combustion, in quiescent air, was established. The isolated particle combustion theory serves as the basis for the combustion interaction and mass transfer in a spherical cloud of dispersed nanothermite particles. The type of group combustion is strongly dependent on the diffusion of vapour products, i.e., the interaction is more pronounced when the diffusion of vapour products is higher. The group combustion regimes in dispersed nanothermites were identified and delineated.

Fusion of CMONOC and ERA5 PWV Products Based on Backpropagation Neural Network

Data fusion is an effective method to obtain high-precision and high-spatiotemporal-resolution precipitable water vapor (PWV) products, which play an important role in understanding climate change and meteorological monitoring. However, existing fusion methods have some shortcomings, such as ignoring the applicability of the model space or the high complexity of model operation. In this study, the high-precision and high-temporal-resolution Global Navigation Satellite System (GNSS) PWV was used to calibrate and optimize the ERA5 PWV product of the European Center for Medium-Range Weather Forecasts Reanalysis 5 (ERA5) with high spatial resolution to improve its accuracy, and its applicability was verified at the spatiotemporal scale. First, this study obtained accurate GNSS PWV from meteorological data from stations and used it as the true value to analyze the distribution of the ERA5 PWV in mainland China. The results showed that the ERA5 PWV showed significant spatial and temporal differences. Then, a backpropagation neural network (BPNN) fusion correction model with additional constraints was established. The correction results showed that the bias of the ERA5 PWV mainly fluctuated near 0, the correlation between the ERA5 PWV and GNSS PWV was increased to 0.99, and the positive improvement rate of the root-mean-square error (RMSE) was 95%. In the temporal scale validation, the RMSE of the ERA5 PWV decreased from 2.05 mm to 1.67 mm, an improvement of 18.54%. In the spatial scale validation, the RMSE of the four seasons decreased by 0.26–80% (spring), 0.28–70.71% (summer), 0.28–45.23% (autumn), and 0.30–40.75% (winter). Especially in the summer and plateau mountainous areas where the ERA5 PWV performance was poor, the model showed suitable stability. Finally, the fusion model was used to generate a new PWV product, which improved the accuracy of ERA5 PWV on the basis of ensuring the spatial resolution.

Enhanced photocatalytic splitting of photothermally induced water vapor to evolve hydrogen

Solar energy conversion using photocatalytic water splitting shows promising potential for resolving the current energy crisis. To split vapor into hydrogen in this study, we built a surface carbonized wood/TiO2 (C-wood/TiO2) photothermal-photocatalytic system. Natural wood that had been surface carbonized enabled stable steam production and produced a solid/gas reaction interface with a lower Gibbs free energy, enabling TiO2 to produce hydrogen photocatalytically without the need for a co-catalyst made of a noble metal. The carbonized surface was able to transfer photogenerated electrons quickly from TiO2, while also significantly enhancing solar spectrum absorption. The C-wood/TiO2 system demonstrated efficient solar spectrum utilization in vapor production and hydrogen evolution. The C-wood/TiO2 system's hydrogen evolution rate under AM 1.5G light irradiation was 487.4 μmol·m−2·h−1when using deionized water, and the cycling experiment demonstrated long-term stability. Additionally, this system could evolve hydrogen from seawater (248.1 μmol·m−2·h−1). This study showed the photothermal-photocatalytic biphasic system's strong suit and potential for producing hydrogen.

Variability of Water Vapor in Central Mexico from Two Remote Sensing Techniques: FTIR Spectroscopy and GPS

Abstract Total column H2O is measured by two remote sensing techniques at the Altzomoni Atmospheric Observatory (19°12′N, 98°65′W, 4000 m above sea level), a high-altitude, tropical background site in central Mexico. A ground-based solar absorption FTIR spectrometer that is part of the Network for Detection of Atmospheric Composition Change (NDACC) is used to retrieve water vapor in three spectral regions (6074–6471, 2925–2941, and 1110–1253 cm−1) and is compared to data obtained from a global positioning system (GPS) receiver that is part of the TLALOCNet GPS-meteorological network. Strong correlations are obtained between the coincident hourly means from the three FTIR products and small relative bias and correction factors could be determined for each when compared to the more consistent GPS data. Retrievals from the 2925–2941 cm−1 spectral region have the highest correlation with GPS [coefficient of determination (R2) = 0.998, standard deviation (STD) = 0.18 cm (78.39%), mean difference = 0.04 cm (8.33%)], although the other products are also highly correlated [R2 ≥ 0.99, STD ≤ 0.20 cm (<90%), mean difference ≤ 0.1 cm (<24%)]. Clear-sky dry bias (CSDB) values are reduced to <10% (<0.20 cm) when coincident hourly means are used in the comparison. The use of GPS and FTIR water vapor products simultaneously leads to a more complete and better description of the diurnal and seasonal cycles of water vapor. We describe the water vapor climatology with both complementary datasets, nevertheless, pointing out the importance of considering the clear-sky dry bias arising from the large diurnal and seasonal variability of water vapor at this high-altitude tropical site.

A miniatured built-in surface ionization oven for the compact microwave ion source

At Peking University (PKU), a compact 2.45 GHz microwave ion source was developed to obtain high-intensity Li+ beam. To improve the generation efficiency of Li+ ions, we developed a built-in lithium oven named surface ionization oven (SIO), which consists of a heating oven for lithium vapor production and a surface ionizer for the ionization of lithium neutrals. Consequently, the surface ionization and electron cyclotron resonance heating (ECRH) principles are combined within the compact microwave ion source. In this work, the structure and materials of the SIO are investigated systemically to lower thermal risk and increase ionization efficiency. The oven is heated by resistance heating. To minimize the heat loss, polished stainless steel shields are used to surround the oven. The surface ionizer is installed at the exit of the nozzle of the heating oven. It consists of six rhenium wires with the diameter of 0.25 mm inside the ionizer tube. Limited space near the microwave window, the dimension of SIO is ⊘ 13.5 mm × 40 mm. This source has been tested with only heating oven and SIO. With only heating oven, which means the absence of surface ionization, and a 200 eμA pulsed Li+ ion beam was stably extracted from this ion source. When the surface ionizer and the heating oven work together, a pulsed Li+ ion beam of 800 eμA is obtained, which increased by about 300%. The experiment proved that surface ionization could dramatically increase the discharge efficiency of lithium plasma in ECRIS.

Performance improvement of NH3–H2O absorption chiller with a combined generator

The present experimental work investigates the impact of an innovative falling-film and plate combined generator, associating vapor production and purification, on the performance of an NH3–H2O absorption chiller of 5-kW cooling capacity. The impact of the flooding of the lower part of the exchanger on the performance of the machine is investigated: It decreases the COP by 33% and cooling capacity by 38%. Solution sub-cooling at the combined generator inlet improves the purity of the ammonia vapor produced, but degrades the performance of the chiller. A design of experiments is defined to characterize the performance of the combined generator, which is highly impacted by the solution mass flowrate and concentration. Then, two correlation forms are used to predict the performance, and the adapted NTU model yields better results. Finally, for an air-conditioning application, a low solution mass flowrate allows the energy consumption to be reduced by approximately 15% but it requires a higher temperature for the heat source; while the increase in the solution mass flowrate degrades the performance but enables the machine to self-regulate at a low heat source.

Evaluation of Water Vapor Product from TROPOMI and GOME-2 Satellites against Ground-Based GNSS Data over Europe

A novel integrated water vapor (IWV) product from TROPOspheric Monitoring Instrument (TROPOMI) is validated together with a Global Ozone Monitoring Instrument-2 (GOME-2) standard product. As reference, ground-based Global Navigation Satellite Systems (GNSS) IWV data in 235 European stations from May 2018 to May 2019 are used. Under cloud free situations, a general comparison is carried out. It suggests that TROPOMI IWV exhibits less bias than GOME-2 and better results in the dispersion and regression parameters. Moreover, TROPOMI presents more homogeneous results along the different stations. However, TROPOMI is found to be overestimating the IWV uncertainties and being, therefore, too conservative in the confidence interval considered. The dependence of satellite product performance on several variables is also discussed. TROPOMI IWV shows wet bias of 5.7% or less for IWV < 10 mm (TROPOMI) and dry bias of up to −3% (TROPOMI). In contrast, GOME-2 shows wet bias of 30% or less for IWV < 25 mm (GOME-2) and dry bias of −12.3% for IWV > 25 mm. In addition, relative standard deviation (rSD) increases as IWV increases. In addition, the dependence on solar zenith angle (SZA) was also analyzed, as solar radiation bands are used in the retrieval algorithm of both instruments. Relative mean bias error (rMBE) shows positive values for GOME-2, slightly increasing with SZA, while TROPOMI shows more stable values. However, under high SZA, GOME-2 IWV exhibits a steep increase in rMBE (overestimation), while TROPOMI IWV exhibits a moderate decrease (underestimation). rSD is slightly increasing with SZA. The influence of cloudiness on satellite IWV observations is such that TROPOMI tends to overestimate IWV more as cloudiness increases, especially for high IWV. In the case of GOME-2, the rSD slightly increases with cloudiness, but TROPOMI rSD has a marked increase with increasing cloudiness. TROPOMI IWV is an important source of information about moisture, but its algorithm could still benefit from further improvement to respond better to cloudy situations.