Absorption Unit Research Articles

The Capability to Make Ice from Sunlight Utilizing a New Absorption Unit of Nano-Coated Ammonia/Calcium Chloride

In southern Jordan, the ice machine was designed, produced, operated, and fully examined at Mutah University, a unique Nano-coated ammonium/calcium chloride absorption sun unit. Analytical and experimental assessments on the use of ammonia/calcium chloride absorption unit ice produced. The new study has decreased energy emission by the Nano ice-making company while enhancing Nano's ice machine's nuclear power compared to standard solar chiller absorption that is not used in the current research. Our case was the world's first research to examine the effect of a nanoparticle combination of paint on an absorption cooling system used to make ice by the sunlight. The result of the test was quite encouraging. The combination of paint and nanofluid particle materials has boosted the accessibility to sun-based cooling processes and their capability to make ice of absorption. In addition, 0.6 was found to be a pretty good COP for the ammonia/calcium chloride solar system of absorption.

Influence of Leachate and Nitrifying Bacteria on Photosynthetic Biogas Upgrading in a Two-Stage System

Photosynthetic biogas upgrading using two-stage systems allows the absorption of carbon dioxide (CO2) in an absorption unit and its subsequent assimilation by microalgae. The production of microalgae requires large amounts of nutrients, thus making scale-up difficult and reducing economic feasibility. The photosynthetic process produces oxygen (O2) (1 mol per mol of CO2 consumed), which can be desorbed into purified biogas. Two-stage systems reduce its impact but do not eliminate it. In this study, we test the use of landfill leachate as a nutrient source and propose a viable and economical strategy for reducing the O2 concentration. First, the liquid/gas (L/G) ratio and flow mode of the absorber were optimized for 20% and 40% CO2 with COMBO medium, then landfill leachate was used as a nutrient source. Finally, the system was inoculated with nitrifying bacteria. Leachate was found to be suitable as a nutrient source and to result in a significant improvement in CO2 absorption, with outlet concentrations of 0.01% and 0.6% for 20% and 40% CO2, respectively, being obtained. The use of nitrifying bacteria allowed a reduction in dissolved oxygen (DO) concentration, although it also resulted in a lower pH, thus making CO2 uptake slightly more difficult.

Automatically Adaptive Ventilated Metamaterial Absorber for Environment with Varying Noises

AbstractAn automatically adaptive metamaterial sound absorber is designed, which can absorb tunable low‐frequency (<500 Hz) sounds under ventilated conditions by designing a feedback circuit to actively detect the noise signals and adjust the sliders on the reconfigurable absorbers. The automatically adaptive ventilated absorber provides an intelligent route to adapt for different low frequencies, through adjusting the sound absorption units directly in accordance with the external environment while retaining high‐efficiency absorption and ventilation. The intelligent sound absorber is demonstrated experimentally and the effective model of coupled lossy oscillators is employed to understand its mechanism. In the future, the absorber that is fabricated can be adjusted to adapt for different working frequencies in stunning applications such as ventilated smart windows, which not only effectively solves the influence of external noise but also provides a fresh and bright working environment. The automatically adaptive absorber should also find promising applications in ducts, where the frequencies of noises can vary time by time, and it is often difficult and inaccurate to manually tune an absorber in such scenarios.

Performance optimization of ground rubberized green concrete with metakaolin

The disposal of waste vehicle tires is an environmental and health problem, as their recycling is very difficult. One of the effective ways of recycling is using these tires as partial replacement of Portland cement in construction industry. In this study, a systematic experimental study (by making 810 laboratory samples) is performed on concrete made with finely ground rubber (GR) and metakaolin (MK) as partial replacements of cement to investigate the compressive strength, splitting tensile strength, flexural strength, water absorption, and dry unit weight. The main goal of this study is to achieve the optimal proportions of concrete incorporating GR and MK by maximizing mechanical strengths while minimizing the water absorption (WA) of concrete. To do so, 7 concrete mixtures containing GR are produced with 3 different cement contents: 350, 400, and 450 kg/m3 in conjunction with 2 different water-cement ratios: 0.45 and 0.50. Also, 1 concrete mix is used to optimize the concrete with hybrid blends of GR and MK by employing the response surface methodology (RSM). GR and MK are applied as partial replacements of Portland cement in ranges of 0–30 vol% and 0–20 vol%, respectively. The results show that the use of GR and MK in concrete has a significant effect on its mechanical and durability properties and, thus, reduces the cement consumption which can contribute to decreasing the negative impacts of cement production on the environment. According to the optimization results, 4.2% and 19.5 vol% replacements of cement with GR and MK, respectively, can be considered as the optimum mixture compositions of hybrid concrete to maximize compressive and splitting tensile strengths by about 1–4% and 6–8%, respectively, while minimizing WA by about 48%. Depending on the flexural strength results, the amounts are changed into 1.8% and 14.7% while the flexural strength increases by about 11%.

Power Generation using Hybrid Energy System for Domestic Purpose

We all are aware that the world is precisely running towards a quest for a substitute energy source. Till today, the maximum power requirement is met with the help of fossil fuels. Anyways the estimates which were made recently have predicted that the usage of the fossil fuels like oil and coal might last only till 2030, and later we will have to switch over to the usage of more efficient sources and emerging technologies. According to current situation the further usage of oil and coal will be replenished and whole world will need to foster for renewable energy source which can satisfy the growing needs of the future generation. For the past few years solar and wind energy have already been trapped and are widely accepted as an alternative source of energy. But in this paper we have planned to concatenate the three outcomes i.e. heat, pressure and sound. Most of the times these three energies are considered as unwanted source of energy and they go unnoticed. With the help of Peltier module, Piezoelectric transducer and sound absorption unit the energies like heat, pressure and noise can be converted into electrical energy respectively. Piezoelectric plate transducer is capable of producing energy using the pressure put on the piezo electric plate. In this paper a footstep piezoelectric plate is used easy to incorporate and even effect cost wise. Peltier module is a thermoelectric device which has the capability of converting the thermal/heat energy into electricity. It primarily works based on the principle of Seeback effect. This device is built using 2 different semiconductor material like p-type and n-type. As the heat emerges and spreads through the material, charge carriers begin to cold side from hot side. The resultant voltage is proportional to the difference in temperature between the layers of the device. As long as there is a difference in temperature the material keeps generating the potential difference. The voltage produced by the entire Peltier module is function of time and the temperature difference. The voltage varies with the change in temperature gradient and time. The sound absorption unit uses sound as an input for producing electric energy, because lot of sound is wasted in our surrounding where in it can used as a source of energy. By using these non-conventional type of energy resources, the generation of power can be achieved with a minimal cost and it will also pave a way to the conservation of the conventional energy source for future needs. This energy thus generated is boosted and stabilized using a DC-DC chopper and later utilized to operate a DC load.

Titania-Supported Ni2 P/Ni Catalysts for Selective Solar-Driven CO Hydrogenation.

Solar-driven Fischer-Tropsch synthesis (FTS) holds great potential for the sustainable production of fuels from syngas and solar energy. However, the selectivity toward multi-carbon products (C2+ ) is often hampered by the difficulty in the regulation of transition metals acting as both light absorption units and active sites. Herein, a partial phosphidation strategy to prepare titania supported Ni2 P/Ni catalysts for photothermal FTS is demonstrated. Under Xenon lamp or concentrated sunlight irradiation, the optimized catalyst shows a C2+ selectivity of 70% at a CO conversion of >20%.Conversely, nickel metal in the absence of Ni2 P delivers negligible C2+ products (≈1%) with methane being the major product (>90%). Structural characterization and density functional theory calculation reveal that the partial phosphidation allows exposed metallic Ni to be active for CO adsorption and activation, while the existence of Ni2 P/Ni interface is responsible to inhibit CO methanation and promote C-C coupling of adsorbed *CH intermediates. This work introduces a novel phosphidation strategy for nickel-based photothermal catalysts in efficiently harnessing solar energy, and regulating the reaction pathways for CO hydrogenation to deliver high value products.

Effect of long-term and heating storage on honey visible spectrum: an alternative parameter for quality monitoring of bracatinga honeydew honey

Bracatinga (Mimosa scabrella Bentham) honeydew honey (BHH) is a peculiar Brazilian honey. It is produced only every 2years, which raises concerns about its quality since it can be submitted to different storage conditions until a new harvest is carried out. Therefore, this study investigated the changes in the visible spectrophotometric profile (VSP) of BHH during its storage at room temperature over 24months and 40°C for 4months. Our findings indicated a similar VSP between the BHH samples, but that varied according to the storage condition. These changes were associated with the formation of brown compounds, such as 5-hydroxymethylfurfural, which has a maximum limit established for honeys. Thereby, absorbance above 0.500 absorption units between 380 and 410nm was proposed as indicative of BHH exposure to prolonged heating with significant loss of its quality. Still, a regression model for absorbance at 380nm was proposed aiming to predict the BHH storage time at room temperature, since storage time longer than 20months at average temperatures of 23.0 ± 2.3°C do not seem to be suitable for BHH. Thus, the VSP showed potential for monitoring BHH quality.

Development of a new high-capacity formaldehyde absorption unit for environmental problems solving and resource saving in formalin production

Ways of further intensification of formaldehyde absorption process and new constructions of more compact apparatuses have been developed on the basis of generalization of results of experimental study of regularities of mechanism and kinetics of formaldehyde absorption in conditions of formalin production. The most effective and for intensification of formaldehyde absorption process are vortex apparatuses in the form of a cascade of one-stage vortex apparatuses, or in the form of a vortex column including three vortex phase contact stages. A new splash trap with bag filtering elements was developed for effective fog catching.

Air side-stream ammonia stripping in a thin film evaporator coupled to high-solid anaerobic digestion of sewage sludge: Process performance and interactions

Air side-stream ammonia stripping in a thin-film evaporator (TFE) is proposed for the first time to control total ammonia nitrogen (TAN) concentration in a centralized full-scale plant performing high-solid anaerobic digestion (HSAD) of sewage sludge (SS). In this process, anaerobically digesting sludge (ADS) is continuously recirculated from the digester to the TFE unit where ammonia is stripped by an air stream. The stripped ammonia reacts with sulfuric acid in an absorption unit to produce ammonium sulfate. Overall, HSAD coupled to air side-stream ammonia stripping results in a twofold production of fertilizers (i.e. ammonium sulfate and SS digestate) recycling nutrients from organic wastes in agreement with the principles of circular economy. This study evaluates the influence of different operational airflow rates, temperatures and CO2 concentrations on air side-stream ammonia stripping in the TFE without alkali addition and the impact of air-based ammonia stripping on HSAD performance at full-scale. The study also investigates the chemistry and the interaction between the ammonia and carbonate subsystems of ADS and clarifies the stoichiometric relationship between ammonia and CO2 stripping.

Energy, exergy and pinch analyses of a novel energy storage structure using post-combustion CO2 separation unit, dual pressure Linde-Hampson liquefaction system, two-stage organic Rankine cycle and geothermal energy

The cost of electricity production and its purchase price markedly differ at different hours of the day; therefore, the idea of storing electricity during off-peak hours (low price) and its use during peak hours (high price) is discussed. In this study, a novel integrated structure for separating CO2 from the output smoke of a power plant using a chemical absorption unit via the post-combustion and CO2 liquefaction method by the dual pressure Linde-Hampson liquefaction system during off-peak hours is developed. The low-temperature organic Rankine cycle and the gas turbine power production unit are used to produce power during peak hours. The post-combustion CO2 separation unit produces 9307 kmol/h CO2 from the power plant's output smoke by absorbing 249.6 MW heat flow from the geothermal energy and 24.42 MW power. At hours when the energy demand is low, the produced CO2 is converted into condensed liquid form by receiving 18.31 MW power. When the demand for electric energy consumption is increased, this integrated structure produces 11.61 MW power. The multi-functional LCES system round trip and baseline LCES system exergy efficiencies are 36.75% and 58.48%, respectively. The exergy analysis results illustrate that the highest exergy destruction contribution in the equipment belongs to the fractionating columns (48.52%), heat exchangers (43.62%), and compressors (2.86%). The heat exchanger network related to the HE12, HE15, HE16, and HE18 multi-stream heat exchangers are extracted by pinch analysis. The sensitivity analysis illustrates that the exergy efficiency of the power generation cycle, baseline LCES plant, and multi-functional LCES structure increase up to 33.19%, 60.87%, and 21.14%, respectively when the pumped pressure of liquid carbon dioxide at peak consumption increases from 80 bar to 120 bar.

A parameter design method for multifrequency perfect sound-absorbing metasurface with critical coupled Helmholtz resonator

The low-frequency harmonic components of urban substation noise are easy to annoy the residents. Multi-frequency perfect sound-absorbing metasurface based on the Helmholtz resonator (HR) is an alternative solution to suppress the low-frequency harmonic noise. This paper proposes an efficient design method of structural parameter for the multi-frequency perfect sound-absorbing metasurface. Taking the perfect sound absorption at the target frequency as objective and the structural parameters of HR as optimization variables, the structural parameter optimization model of multi-frequency perfect sound-absorbing metasurface is established and solved by the sequential quadratic programming algorithm. The proposed design method effectively overcomes the deterioration of sound absorption performance caused by the combined design of multiple perfect sound absorption units. Utilizing the proposed method, we designed a multi-frequency perfect sound-absorbing metasurface to absorb the four harmonic components of an urban substation noise simultaneously. The finite element simulation results and the experimental results of the physical sample indicate that the designed multi-frequency perfect sound-absorbing metasurface can satisfy critical coupling to achieve perfect sound absorption at all target frequencies.

Characteristics of hemp fibre reinforced foam concretes with fly ash and Taguchi optimization

This study presents investigation on microstructural, mechanical, durability and thermal characteristics of hemp fibers (HFs) reinforced foam concrete with fly ash (FA) and Taguchi optimization approach. Three series of foam concretes mixtures were produced with foam contents of 50, 75 and 100 kg/m3. There is a reference mixture without HFs and FA. Thus, mixtures contain FA as cement replacement at the concentrations of 0%, 10%, 20%, 30%, 40% and 50%. HFs with varying fiber length were introduced into mixes at concentrations of 0.75%, 1.5% and 3% by weight of cement. Slump test was done to see workability. Compression and flexural properties were determined at 7, 28 and 91 days. Durability was investigated by high temperature, freeze–thaw and sulphate exposures. Thermal conductivity, drying shrinkage, porosity, water absorption and dry unit weight properties of foam concretes were also investigated. Experimental results were analyzed using Taguchi optimization approach. Addition of HFs provides very large compressive and flexural strength enhancements. FA addition reduces the drying shrinkage and thermal conductivity while it increases the high temperature resistance of foam concretes.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ РАБОТЫ УСТАНОВКИ ОСУШКИ ТОПЛИВНОГО И ПРЕДЕЛЬНОГО ГАЗА

The paper proposes a solution to the problem of reducing corrosion wear of the 
 pipeline for hydrogen sulfide gas caused by the accumulation of ammonium salts during the pipeline 
 operation. The possibility of retrofitting the existing process diagram of the fuel and limit gas drying 
 unit with an absorption unit was considered, as well as the absorption column was calculated and its 
 main geometric dimensions were determined

Design of a heat recovery unit using exhaust gases for energy savings in an absorption air conditioning unit

Abstract Optimum utilisation of the available energy is vital to eliminate waste heat and address other environmental issues. This study is concerned with the design of a heat exchanger for the optimum use of loss heat from flue gases. The heat content in exhaust gases can be applied in the absorption chiller to preheat a dilute solution (lithium bromide) before entering the high-temperature generator. The exploitation of the energy from a glass furnace outlet flue gas temperature of 400 °C will reduce the rate consumption of natural gas. The thermodynamic properties of flue gases were determined based on chemical composition analysis measured by the gas analyser. Moreover, the solution at the inlets and outlets of the Li-Br absorption chiller unit components was estimated using heat and mass balance equations. The heat recovery unit was designed to extract heat from flue gases to preheat, directly or indirectly, the Li-Br solution before entering the high-pressure generator using water as an intermediate solution. The heat exchanger design specification was determined for both cold fluids (Li-Br and H2O) at different tube diameters using copper and steel materials. Furthermore, the theoretical design analysis was executed using a FORTRAN program. It was found that the compact direct heat exchanger showed the best performance with respect to the overall heat transfer area, while the shell-and-tube heat exchanger was favourable because of its simple design and manufacturing. The results showed that the minimum outlet flue gas temperature was 200 °C to keep the glass furnace operating as a natural draught system. The feasibility study was carried out by the CONSUKORRA Company (Hitachi agent in Egypt) based on the current study data. The proposed feasibility study showed that the annual fuel savings was about 23%, while the annual cost saving was 18%. Moreover, the coefficient of performance of absorption unit will be enhanced by 34% after installing the heat recovery unit.

New Apparatus for CO2 Solubility Measurements From Total Pressure-composition Data

Carbon capture, utilization, and storage (CCUS) is among the selected strategies to restrain the effects of climate change in the near future. However, the amount of CO2 that is captured currently is much lower than the levels required for successful climate action. One key to unlock CCUS deployment is reducing the cost of captured CO2. The assessment of new technologies or different operating scenarios through process simulation rely on thermodynamic models that can reproduce the system’s properties. These models are fine-tuned based on accurate phase and chemical equilibrium measurements, especially vapor-equilibrium data. However, the measurement of such properties is often cumbersome and expensive. In this context, the goal of this work is to provide a reliable basis for thermodynamic modelling and process simulation of a CO2 absorption unit using a mixed salt solution. The work entails the commissioning and measurement of equilibrium data, which will be followed by the correlation of such properties using the extended UNIQUAC model. The developed model will be suitable for process simulations and should provide insights on energy consumption and cost of captured CO2.

Energy and Exergy Analysis of an Absorption and Mechanical System for a Dehumidification Unit in a Gelatin Factory

In this paper, an energy and exergy analysis is applied to the air dehumidification unit of a liquid desiccant system in an industrial gelatin conveyor dryer. The working fluid is a binary solution of lithium chloride (LiCl) in water. Dry air is used in order to decrease the amount of liquid in the gelatin. Therefore, the environmental air must have its absolute humidity reduced from about 12 g/kg to the project target, which is 5 g/kg. The process is a cycle using an absorption desiccant unit (LiCl in water), where the weak solution absorbs water vapor from the air. In the regenerator, condensation of the solution (desorption) from the moist air occurs. As a result, the steam consumption of the desorber and electrical power used for the vapor compression chiller (with ammonia, NH, as working fluid) are the primary sources of cost for the factory. To improve the plant’s energy and exergy behaviors, the process is evaluated using a mathematical model of the system processes. In addition, we evaluate the substitution of the vapor compression chiller by an absorption unit (lithium bromide (LiBr) in water). The performance indicators of the compression vapor systems showed the best results. Even when using the condenser’s energy to pre-heat the solution, the installed system proved to be more effective.

A new durability assessment method of the tuffs used in some historical buildings of Cappadocia (Turkey)

Cappadocia region in Turkey is known as a touristic and historical area with volcanic rocks formed by the effect of intense Neogene calcalkaline volcanism. Rhyolitic to trachyandesitic tuffs, being widespread as a volcanic rock in this region, are used as building stone in historical structures and many monuments with cultural heritage. However, since they have variable durability performances, it is important to evaluate the durability of tuffs for restoration purposes. The aim of this study is to characterize the tuffs using their properties including effective porosity, water absorption, dry and saturated unit weights, dry and saturated uniaxial compressive strengths, dry and saturated point load strengths, dry and saturated sonic velocities and slake durability index, and to estimate the long-term durability of tuffs based on the correlation between field performances and measured properties of the tuffs. In the context of this study, 13 tuff samples used in ancient monuments with good durability performances were taken from nine quarries of Kayseri and Aksaray areas in the Cappadocia region. The physical and mechanical properties of these tuffs were investigated. The properties of these tuffs and the ones with poor durability based on the literature data were compared. A series of correlation graphs using unit weight, effective porosity, water absorption, sonic velocity, and uniaxial compressive strength values of all tuffs has been developed to identify durable and non-durable tuffs. Among these, effective porosity (by volume)-dry sonic velocity and effective porosity (by volume)-dry uniaxial compressive strength pairs yield better durability assessment for the tuffs.

Experimental and numerical analysis of hybrid solar heating and cooling system for a residential user

The paper presents an experimental investigation of a solar dish concentrating system with thermal collectors, along with a numerical investigation of a solar cooling installation based on such system by means of dynamic simulation. The main aim of this study is the analysis of heat generation from the system for heating and cooling purposes, with the use of sorption chillers. A computer simulation of the dynamic operation of the proposed solar heating and cooling system was developed within TRNSYS software. The experimental data were used to validate the model of the concentrator and solar collectors. Successively, a solar heating and cooling installation for a residential application, integrating the different configurations of solar energy collecting devices and thermally driven chillers, was proposed and dynamically simulated. Flat-plate, evacuated tube and photovoltaic-thermal collectors were considered along with absorption and adsorption chiller units. In the present study, different system configurations, localities and time bases were considered to investigate the energy and economic performance of the system.The model of the solar dish and collector arrangement overestimates the produced energy by less than 5% as compared to the experimental study. The results show that the space cooling demand is matched in 23.6 and 46.2% by solar energy in Warsaw, while in Lisbon from 38.2 to 46.1%. The simple payback period of the investigated system configuration was for Warsaw between 18.1 years for the combination of flat-plate collector and absorption chiller and 27.2 year for the photovoltaic-thermal collector with adsorption chiller.

Electroscrubbers for removing volatile organic compounds and odorous substances from polluted gaseous streams

The treatment of waste gaseous streams has become an important topic of environmental concern. One promising technology is electroabsorption which combines two important treatment processes into a single unit. In this sense, this review compiles the information available in the recent literature showing the hybridization of absorption units with electrochemical cells for treatment of gases polluted with volatile organic compounds and odorous substances. This approach is compared with other competing technologies, paying special attention to the technology readiness level. Although from the laboratory tests, it appears to be a promising methodology for the degradation of volatile organic compounds and environmental odorous gases; this critical review points out that more research is needed to raise the technology readiness level of this treatment technology in a context in which the society is demanding more and more sustainable technologies.

Simultaneous removal of CO2, NOx and SOx using single stage absorption column

Capturing flue gases often require multiple stages of scrubbing, increasing the capital and operating costs. So far, no attempt has been made to study the absorption characteristics of all the three gases (NO, SO2 and CO2) in a single stage absorption unit at alkaline pH conditions. We have attempted to capture all the three gases with a single wet scrubbing column. The absorption of all three gases with sodium carbonate solution promoted with oxidizers was investigated in a tall absorption column. The absorbance was found to be 100% for CO2, 30% for NO and 95% for SO2 respectively. The capture efficiency of sodium carbonate solution was increased by 40% for CO2 loading, with the addition of oxidizer. Absorption kinetics and reaction pathways of all the three gases were discussed individually in detail.