Water Scrubbing Research Articles

A prospective absorption system for marine NOx removal from simulated gas using Na2SO3/urea composite absorbents in bubble reactor

The large amount of NOx emitted from ships causes great harm to the environment and to health. Due to the strict regulations on NOx emission, it is urgent to develop a marine NOx absorption technology with efficient NOx removal and less nitrate residue in scrubber water. This paper proposed a novel composite Na2SO3/(NH2)2CO absorption system that could efficiently absorb NOx from ships. The NOx absorption process was studied in combination with a bubble reactor. Na2SO3 could react with NOx to convert the N into nitrite and N2, and (NH2)2CO could reduce the nitrate, nitrite, and NOx to N2. The main key parameters such as Na2SO3 concentration, (NH2)2CO concentration, SO2 concentration, oxygen concentration, NOx oxidation degree, initial NOx concentration, initial pH, and temperature were investigated experimentally. The Na2SO3 concentration had great effects on the NOx absorption efficiency. The nitrate concentration was significantly affected by the absorbents concentration, the NOx oxidation degree, the temperature, and the O2 concentration (0%–8%). Acid condition was not conducive to NOx absorption. A NOx absorption efficiency of 92.3%, a nitrate content of 13.1 mg/L, and the nitrite content of 21.3 mg/L were achieved under the optimal conditions in which, Na2SO3 was 0.25 mol/L, (NH2)2CO was 0.4 mol/L, SO2 was 700 ppm, NOx oxidation degree was 20%, initial NOx was 1000 ppm, and O2 was 12%. The Na2SO3/(NH2)2CO absorption system satisfied the regulations on NOx removal efficiency and nitrate concentration of scrubber water and therefore showed excellent application prospects on ships.

Rancang Bangun Alat Purifikasi Biogas Water Scrubber Berbasis Mikrokontroler

Biogas is one of the potential renewable energies to be developed in Indonesia. Biogas contains CH 4 as the primary element, besides containing impurities such as H 2 S and CO 2 . The presence of these gases can reduce the quality of biogas and can cause corrosion in equipment. Therefore, it is necessary to purify the gas content, one of them by using a water scrubber. Purification of CO 2 and H 2 S gas levels by using a water scrubber is a physical purification. Purification can also be done chemically, one of them by using CaO. In this research, the media used to make biogas were water hyacinth, cow dung and vegetables, while the media for purification used wood sawdust pellets, quicklime pellets (CaO) and mixed lime and wood lime pellets. The purification process was divided into 3 experiments, the best result was the third experiment with the percentage of biogas production by 15 kg of vegetables with 7.5 kg of cow dung and 15 liters of water, and adding EM-4 by 5%. The results showed the greatest reduction in CO 2 gas with a water scrubber media of 54% while the largest H 2 S gas value with a water scrubber media with CaO and sawdust by 66%.

Purificación del Biogás para la producción de Biometano, a través de sistemas de filtración de CO2 y vapor de agua.

El biogás es un biocombustible producto de la digestión anaeróbica de productos orgánicos. Su poder calorífico es bajo (18 MJ/Nm3) y mejora cuando se convierte en biometano por eliminación de CO2, vapor de agua y H2S. Nos propusimos desarrollar tecnología para purificar el biogás obtenido en la planta HPTC del Fundo La Católica de El Pedregal-Majes, para lo cual se diseñó, construyó y evaluó un sistema de filtrado por depuración con agua presurizada (Scrubber), para reducir el contenido de CO2 a valores menores a 5.0% V/V; para ello trabajamos a 03 presiones de operación (6, 9 y 10bar) combinadas con 03 temperaturas (10, 15 y 20ºC), obteniéndose el mejor resultado de purificación, 4,3% V/V de CO2 a 10°C y 10bar de presión. El sistema toma el biogás, lo presuriza e introduce por un tubo de acero de 0.05m de diámetro y 3,0m de altura ubicado en la parte inferior, en cuyo interior se encuentran 04 tubos de PVC de diámetros decrecientes, con perforaciones y separadores que aumentan la superficie de contacto y por ende la absorción del CO2. Igualmente, se desarrolló un sistema de filtrado PSA para el vapor de agua; se presuriza el biogás e introduce en la parte inferior por un tubo de acero de 0,2m de diámetro y 0,5m de altura, en cuyo interior se encuentra la zeolita como adsorbente. El flujo de biogás es controlado a través de válvulas y el filtrado se retira por la parte superior, logrando reducir el contenido de vapor de agua a 2.2% V/V a 8bar de presión y temperatura ambiente.

Polyhydroxamic acid as an efficient metal chelator and flocculant for wastewater treatment

Hydroxamic acid containing organic polymeric flocculants were synthesized from three different commercially available polymeric flocculants, such as WAS590, Zetag 4100, and Zetag 4110. These three polymers are acrylamide and acrylic acid‐based copolymers with different molecular weights and anionic charge density. The conversion of the amide groups to hydroxamic acid groups in the polymers was carried out by the reaction with hydroxylamine at pH 14. The modified polymers were characterized for structure and composition by elemental analysis, FTIR, and NMR. The chelation activity of the modified polymers was determined toward iron (Fe3+) and copper (Cu2+). The flocculation activity of the non‐modified and modified polymers was evaluated toward produced water and scrubber water. The results showed that all the modified flocculants exhibit better chelation with Fe3+ and Cu2+. In addition, the modified polymers display improved flocculation effect on tested wastewater.

Original

The rapid growth of population, urbanization, economic activities and natural phenomena have affected and simultaneously changed the land use land cover pattern. The main aim of this study is to gain a quantitative understanding of land use land cover changes in Chandauli district from 2000 to 2019. The maximum likelihood supervised classication in ERDAS imagine and ARC GIS software is applied in this study for the preparation of land use land cover maps and analysis of the pattern of land cover through satellite data for the years 2000, 2010 and 2019. The classication of land use land cover is divided into nine major classes i.e. water bodies, sand, cropland, built-up land, fallow land, wasteland, dense forest, open forest and scrub forest. Change detection analysis was also included in this analysis. The general pattern of LULC in this area includes an expansion of Fallow land (18.31 per cent), built-up land (13.43 per cent), open forest and water bodies as well as a reduction in the wasteland (12.59 percent) and dense forest areas in the reference period (2000-2019). The result also indicates that the dominating forest cover exists in southern Chandauli district. The mapping of land use land cover classes is also helpful in the study of change detection and natural resource management.

Exergy and energy analysis of three biogas upgrading processes

The aim of this work was to provide a complete exergy and energy analysis of three biogas upgrading technologies: amine scrubbing, water scrubbing and membrane separation processes. Biogas production and treatment represents a key-process for the application of Circular Economy principles, since allows to reuse/reconvert industrial by-products or agro-industrial waste in a product that can be used in different energy demanding sectors, after proper cleaning and upgrading processes. The three technologies here reported have been implemented in Aspen Plus flowsheets, and were used to upgrade a biogas to biomethane, meeting the UNIT/TS 11537:2019 standards for Biogas to be injected in the gas grid. Each units of all the simulated processes have been analysed calculating total exergy feed, total exergy produced and exergy loss, distinguishing that lost for irreversibility and as waste. Water scrubbing was characterized by the highest values of exergy efficiency (94.5%) and methane recovery (99%), whereas the lowest exergy efficiency belonged to membrane separation (90.8%) that returned also the largest specific energy consumption (0.94 kWh/m3 STP). Conversely, amine scrubbing was characterized by the lowest specific energy consumption value (0.204 kWh/m3 STP) but by an exergy efficiency of 91.1%.

Improving high-pressure water scrubbing through process integration and solvent selection for biogas upgrading

Biogas plays a vital role in many renewable and sustainable energy strategies, where CO2 removal is required to produce biomethane (i.e., biogas upgrading). New ideas and technologies have been proposed to improve the process efficiency of biogas upgrading with liquid absorbents, and ionic liquids have been identified as promising candidates. Meanwhile, there is an urgent need to effectively utilize low-quality waste heat in industry. In this study, two strategies (i.e., waste heat integration and desorption unit modification) were proposed and compared with the original high-pressure water scrubbing; in addition, the effects of the temperatures of the heat source and solvents on the energy usage and cost were further investigated. The results showed that the total cost of the process integrated with waste heat recovery decreased by 6.2% compared with the original high-pressure water scrubbing, and the higher temperature of the waste heat source corresponded to a lower cost. The comparison of different solvents further confirmed that ionic liquid-based solvents were promising, with a potential cost reduction of 24.7%; the properties of the solvent, such as the CO2 absorption capacity, selectivity, and viscosity had significant influences on the total cost, and a new and single index “comparative absorption factor” was proposed to reflect the overall impact of these properties on the cost.

Reclamation of Clay–Resin Mixed Waste Sand by a Hot Waste Alkali Liquor Soaking Assisted with Scrubbing Method

The reclamation of clay–resin mixed waste sand (CRMWS) reused over multiple cycles is difficult, while the commonly used thermal–mechanical reclamation process has some major drawbacks with regard to high acid consumption and low rebonding efficiency in the reclaimed sand. In this paper, a hot waste alkali liquor soaking assisted with scrubbing (HWALSS) reclamation method was proposed to reclaim CRMWS as new sand additional for the green sand molding line, as compared to the thermal–mechanical reclamation method and water scrubbing reclamation method. The properties of the reclaimed sand were investigated, and the reclamation mechanism was also discussed. The experimental results indicate that the reclamation method of HWALSS is feasible. The compressive strength (σ24h) of HWALSS reclaimed sand bonded by sodium silicate binder is 8.17 times and 2.71 times more than that of the thermal–mechanical reclaimed sand and the water scrubbing reclaimed sand, respectively. Morphological analysis reveals that the surface of HWALSS reclaimed sand is both smooth and clean, and the quantity and area of the bonding bridges of the sodium silicate bonded sand are found to be large compared to those of the thermal–mechanical and water scrubbing reclaimed sand, which are the main reasons for the improvement of the compressive strength.

Performance Evaluation of Cyclone Type Scrubber for Bio Gas and Comparison with the Water Scrubbing

Performance Evaluation of Cyclone Type Scrubber for Bio Gas and Comparison with the Water Scrubbing

Modification of Sea Water Scrubber System into Fresh Water of Inert Gas System on the Crude Oil Tanker 85,000 DWT

Each ship carrying a hydrocarbon must be equipped with an inert gas system. On tankers, the function of inert gas is to prevent fires or explosions caused by oxygen levels contained in cargo tanks. Inert gas is produced by cleaning the exhaust gas boiler using a sea water scrubber system. However, seawater has corrosive properties that cause the use of material in scrubber system components to be resistant to corrosion. Therefore, through this research a modification of the sea water scrubber system was made into a freshwater scrubber system. The advantages of a freshwater scrubber system include a low corrosive level that causes the use of inexpensive materials. Modification of seawater scrubber systems into fresh water causes additional components to be made, including adding NaOH tank, expansion tank of freshwater, seawater pumps, freshwater pumps, NaOH pumps, heat exchanger, and wash water treatment unit. Economic calculations are carried out to determine the installation costs and operational costs needed from this modification. Based on the technical and economical analysis, modification of the sea water scrubber system into fresh water inert gas system of Crude Oil Tanker 85,000 DWT can be done with an estimated installation cost of 1.5 Bill. Rupiahs.

Membrane-based technologies for biogas upgrading: a review

Global warming caused by increasing CO2 atmospheric levels is calling for sustainable fuels. For instance, biomethane produced by biogas upgrading is a promising source of green energy. Technologies to upgrade biogas include chemical absorption, water scrubbing, physical absorption, adsorption, cryogenic separation and membrane separation. Historically, water scrubbing was preferred because of the simplicity of this operation. However, during the last decade, membrane separation stood out due to its promising economic viability with investment costs of 3500–7500 €/(m3/h) and operational costs of 7.5–12.5 €/(m3/h). Here we review biogas upgrading by membrane separation. We discuss gas permeation, membrane materials, membrane modules, process configurations and commercial biogas plants. Polymeric materials appear as most adequate for membranes aimed to upgrade biogas. Concerning membrane modules, hollow fibers are the cheapest (1.5–9 €/m2). Multistage configurations provide high methane recovery, of 99%, and purity, of 95–99%, compared to single-stage configurations.

Modelling of renewable gas and renewable liquid fuels in future integrated energy systems

This study conducts an integrated energy system assessment to evaluate pathways for using locally distributed sustainable biomass resources in the conversion to renewable gas and liquid biofuels in future integrated energy systems. A modelling framework with a detailed spatiotemporal representation is used, optimising the usage and transportation of local biomass resources for producing renewable gas and renewable liquid fuels through the OptiFlow model, along with the comprehensive power and district heating model Balmorel, integrating short-term dynamics in the long-term planning horizon. Results for a fossil-independent Danish energy system by 2050 show that production of bio-jet fuel in Denmark would impose high pressure on national biomass resources. Electrofuels, such as biomethanol, have economic viability and promising potentials. The results regarding renewable gas production show that anaerobic co-digestion of a mixed feedstock to produce biogas, which is further upgraded to biomethane using water scrubbing for CO2 removal, would be the preferred option. Biorefineries are located near larger cities to benefit from economy of scale and access to large district heating networks, as excess heat from biorefineries could supply up to 21% of the national district heating demand. On the contrary, biogas plants would be located in the countryside, as the costs of transporting manure are a determining factor. Therefore, our study provides a novel modelling approach, which enables optimisation of geographical distributed resources for renewable gas and liquid fuel production, while taking synergies across energy vectors in account.

Techno-economic and environmental assessment of the main biogas upgrading technologies

Five biogas-to-biomethane upgrading technologies were compared from the environmental and economic points of view: High-Pressure Water Scrubbing (HPWS), Amine Scrubbing (AS), Potassium Carbonate Scrubbing (PCS), Pressure Swing Adsorption (PSA) and Membrane Permeation (MP). Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) methods were used for the comparison. In order to provide a wider picture of the conversion system and its impacts, the biogas production processes, starting from source sorted organic fraction of municipal solid waste, were included. The intention was to maintain the same object for the LCA and the LCC, given that the cost of biogas production had to be included for the calculation of the economic indicators. The cost analysis included also the evaluation of the external costs, derived from the monetization of the air emissions of the systems. The selected functional unit was the upgrading of 1 Nm3 of raw biogas. Data were collected directly from companies providing upgrading plants and confirmed by literature review. A biogas-to-biomethane plant proved to have environmental and economic benefits and, as expected, for larger plant sizes the economic performances improved. AS showed the best environmental performances mainly due to its limited CH4 losses and lower electricity consumption. Considering the contribution from only the upgrading part, AS showed the lowest impacts for the global warming potential (GWP) indicator (respectively 13%, 1%, 23% and 3% less than HPWS, PCS, PSA and MP). However, the results changed for other impact categories: for human toxicity indicator PSA showed lower impacts compared to the other technologies, respectively 7%, 144%, 1% and 9% less compared to HPWS, AS, PCS and MP. For small size plants, HPWS proved to be slightly more cost-effective compared to other technologies. For large size plants, PCS showed the highest net present value. Moreover, the sensitivity analysis showed that the electricity consumption is a key parameter for the economic and environmental results. Its variation proved that for the 60% of cases AS was the best solution in terms of GWP, however 35% and 5% of cases respectively indicated that PCS and MP had the lowest GWP.

Optimal Hot-Dipped Tinning Process Routine for the Fabrication of Solderable Sn Coatings on Circuit Lead Frames.

Previous studies merely focus on the hot dipping properties of lead frame materials used in electronic industry. Yet, the environmentally friendly and cost-efficient traits of hot-dipped tinning process make it a possible promising surface modification technique compared with electroplating. As a result, the optimal hot-dipped tinning process routine is proposed in this paper. The hot-dipped tinning process of four different types of copper foils (C11000, C19400, C19210, and C70250), pretreatment parameters, mechanical properties of Cu substrates, thickness of IMC (intermetallic compound) layers and coatings, and microstructure of coatings were investigated to determine the copper substrate suitable for hot-dipped tinning and the optimized tinning procedures. The results indicate that a proper increase in alloying elements (e.g., Cu-Fe-P series alloys) towards Cu substrate leads to a decrease in hot dipping performance. The proper process routine is determined as alkaline cleaning→water scrubbing→accelerant solvent dipping→drying→hot-dipped tinning→cooling. The appropriate dipping temperature range is 260 to 280 °C, which assists to maintain acceptable micro hardness (i.e., maintaining at least 95% of the original hardness). The optimal dipping time should be set as 6–10 s. The proposed hot-dipped tinning process routine may present a guideline for the fabrication of tin coating in electronic industry.

PEMISAHAN GAS CO2 BIOGAS MENGGUNAKAN ALAT WATER SCRUBBER DENGAN VARIASI LAJU ALIR DAN TEKANAN BIOGAS


 
 
 
 Biogass is produced from fermentation of organic materials such as domestic waste and manure from animal husbandary. To increase the quality of biogass as a fuel, it has to be followed by the increasing of CH4 concentration. It could be done with seperating CH4 from other gases such as CO2. One of separation methode is using a water scrubber with water act as medium which as CO2 is more soluable to water than CH4. The result showed that CO2 absorption was increased followed by the increasing of the pressure and the biogass flow rate. The percentage of CO2 absorption at 2,5 m3 per hour of biogass flow rate and 8 bar was 4,6%, meanwhile it was 11,l% at 10 bar. In the other side, there was 9,5% of CH4 increasing at 10 bar. Therefore, CO2 separation from biogass using water scrubber at 10 bar is better than at 8 bar.
 
 
 

Association Between Eliminating Water From Surgical Hand Antisepsis at a Large Ophthalmic Surgical Hospital and Cost

Alcohol-based surgical scrub is recommended for presurgical antisepsis by leading health organizations. Despite this recommendation, water-based scrub techniques remain common practice at many institutions. To calculate the potential financial savings that a large, subspecialty ophthalmic surgical center can achieve with a conversion to waterless surgical hand preparation. A review of accounting records associated with the purchase of scrubbing materials and water company invoices was conducted to assess direct costs attributable to water consumption and scrub materials for brushless, alcohol-based surgical scrub and water-based presurgical scrub. The flow rate of scrub sinks to estimate water consumption per year was tested. Savings associated with operating room (OR) and personnel time were calculated based on the prescribed scrub times for waterless techniques vs traditional running-water techniques. The study was conducted from January 5 to March 1, 2019. The primary outcomes for this study were the quantity of water consumed by aqueous scrubbing procedures as well as the cost differences between alcohol-based surgical scrub and water-based scrub procedures per OR per year. Scrub sinks consumed 15.9 L of water in a 2-minute period, projecting a savings of 61 631 L and $277 in water and sewer cost per operating room per year. Alcohol-based surgical scrub cost $1083 less than aqueous soap applied from wall-mounted soap dispensers and $271 less than preimpregnated scrub brushes per OR per year in supply costs. The decrease in scrub time from adopting waterless scrub technique could save between approximately $280 000 and $348 000 per OR per year. Adopting waterless scrub techniques has the potential for economic savings attributable to water. Savings may be larger for surgical facilities performing more personnel-intensive procedures.

Hybrid Membrane Distillation and Wet Scrubber for Simultaneous Recovery of Heat and Water from Flue Gas.

Flue gas contains high amount of low-grade heat and water vapor that are attractive for recovery. This study assesses performance of a hybrid of water scrubber and membrane distillation (MD) to recover both heat and water from a simulated flue gas. The former help to condense the water vapor to form a hot liquid flow which later used as the feed for the MD unit. The system simultaneously recovers water and heat through the MD permeate. Results show that the system performance is dictated by the MD performance since most heat and water can be recovered by the scrubber unit. The scrubber achieved nearly complete water and heat recovery because the flue gas flows were supersaturated with steam condensed in the water scrubber unit. The recovered water and heat in the scrubber contains in the hot liquid used as the feed for the MD unit. The MD performance is affected by both the temperature and the flow rate of the flue gas. The MD fluxes increases at higher flue gas temperatures and higher flow rates because of higher enthalpy of the flue gas inputs. The maximum obtained water and heat fluxes of 12 kg m−2 h−1 and 2505 kJm−2 h−1 respectively, obtained at flue gas temperature of 99 °C and at flow rate of 5.56 L min−1. The MD flux was also found stable over the testing period at this optimum condition. Further study on assessing a more realistic flue gas composition is required to capture complexity of the process, particularly to address the impacts of particulates and acid gases.

Biogas purification using water scrubber with variations of water flow rate and biogas pressure

Biogas is a form of alternative energy which can be obtained from the anaerobic degradation process of organic materials. The presence of CO2 in biogas needs to be removed to increase its CH4 concentration, which simultaneously increasing its calorific value and biogas qualities. This study used the water scrubber method to absorb CO2 and separate it from the CH4 contained in biogas. The variables used are the biogas pressures of 2, 3, and 4 bar and water flow rates of 0.1 and 0.15 L/s with a contact time of 60 seconds. The results of this study showed that the greatest effectiveness in both CO2 removal of 99.5 percent and CH4 increase of 38.18 percent were obtained at biogas pressure of 4 bar and water flow rate of 0.15 L/s. The most effective results of CO2 biogas removal were obtained at greater biogas pressures and water flow rates.

Computer simulation of NOx removal from diesel engine off-gases under electron beam and wet scrubber system

NOx emission from diesel engine off-gases in marine transportation sector is still an environmental issue to be solved in present day. Electron beam (EB) followed by a seawater wet scrubber method to removal NOx has been experimentally studied (Chmielewski et al., 2018). In this work numerical simulation of NOx reduction using EB followed by a water scrubber system has been carried out. The first stage was to calculate NOx removal versus dose under EB irradiation. Computer code “KINETIC” and Gear method were used, the model has been improved based our previous work (Zwolinska E. et al., 2015) and verified by the experimental results. The calculation results of NOx removal efficiency was 4.9% at 10.9 kGy dose under EB irradiation, which was a little higher than experimental value (3.5%). Computer program MATLAB was used to study NOx absorption in water. The NOx removal efficiency was increased by 17.5% at 10.9 kGy dose for inlet concentration of NOx being 1333 ppm after EB-water absorption process. At the end, NOx reduction in the simulated marine off-gas using microwave plasma was simulated using computer program Chemical Workbench. Less than 20% NOx was removed from the off-gases in microwave plasma reactor even at 9000 kGy dose for the inlet concentration of NOx being 1500 ppm. EB is more energy efficient than microwave plasma for NOx removal.

A Prospective Method for Absorbing NO2 by the Addition of NaHSO3 to Na2SO3-Based Absorbents for Ship NOx Wet Absorption

A high nitrate concentration in scrubber water is a major factor that restricts ship applications of NOx wet absorption technology. In this paper, an absorption system (Na2SO3/NaHSO3) that can effe...