Adsorption Tank Research Articles

Research on Oil and Gas Adsorption Optimization Based on CFD Modeling and Process Simulation.

In the process of oil extraction and refining, some of the liquid light hydrocarbon components will inevitably evaporate into the atmosphere, causing serious air pollution and safety hazards. This paper is focused on oil and gas adsorption systems to comprehensively optimize key parameters by combining computational fluid dynamics (CFD) modeling with process simulation, enabling the efficient treatment of hazardous materials. First, a CFD model of the hydrocarbon adsorption process is established to the porous media model by a user-defined function (UDF). Subsequently, the mass transfer process of oil and gas in porous media is successfully simulated to obtain the gas distribution in an industrial fixed bed adsorption tower. The adsorption tank is intensified, and the gas distribution in the tank is improved by optimizing the height-to-diameter ratio of the equipment and the design of the intake distributor. Third, the cyclic two-tank adsorption model of the pressure swing adsorption (PSA) process is established for key parameters optimization. Finally, the operating parameters and conditions of the PSA process are suspected by considering five factors affecting the adsorption efficiency: adsorption time, adsorption pressure, adsorption temperature, feed flow rate, and purge ratio of the washing step.

Numerical simulation of the hydrogen charging process in an adsorption storage tank

Adsorption storage utilizing activated carbon is acknowledged as a promising approach for hydrogen storage duo to its high efficiency. This study compares the activated carbon adsorption storage method with the conventional empty tank storage approach. Finite element simulation is conducted to analyze the hydrogen charging process. Results reveal that under conditions with an initial temperature of 281 K and a storage pressure of 50 MPa, the adsorption tank exhibits a higher system volumetric capacity compared to the empty tank, with an increase of 12.6%. Furthermore, the influence of activated carbon's macroporosity and adsorption performance on storage capacity is investigated. It is indicated that increasing macroporosity effectively enhances storage capacity. Additionally, a comparison between the hydrogen storage performance of AX-21 activated carbon and carbon nanotubes (CNTs) highlights the significant impact of adsorption performance of the adsorbent materials on the storage capacity and temperature distribution.

Experimental and numerical investigation of cryogenic no-vent fill (NVF) process using adsorption on activated carbon

This paper describes a novel method of utilizing adsorption to a no-vent fill (NVF) process. A primary goal of the NVF process is to complete the fill process of cryogenic liquid within the allowable pressure of the receiver tank without venting. The use of physical adsorption at cryogenic temperature can suppress the pressure rise of the tank and facilitate the NVF process by adsorbing and storing the vapor at a high density. To prove the effects of adsorption on NVF, we conduct experimental tests of NVF processes of liquid nitrogen (LN2) using adsorption on activated carbon. The experimental apparatus used in tests consists of a 158 L receiver tank, a 180 L supply tank, an LN2 transfer line, and an adsorption storage system. The adsorption storage system, which has a volume of 2.2 L and contains 833 g of granular activated carbon, is precooled by a Stirling cryocooler before the NVF process starts. When the adsorption inlet valve is opened at 48 s, the peak pressure reduction of 3.2 kPa is proved experimentally in the sorption-assisted NVF process. Furthermore, a numerical model for the sorption-assisted NVF is established to investigate the adsorption-related parameters that affect NVF processes. The numerical model is developed by dividing it into NVF and adsorption models and is validated by comparing the predicted tank pressure and filling ratio with the measured data. For four experimental cases, the absolute error of the filling ratio is within 3.3 %, and the absolute error of the pressure is within 10.8 kPa. From numerical simulations, we identify four adsorption parameters: valve opening time, volume ratio of activated carbon and copper, adsorption tank volume, and valve opening degree. The simulation results demonstrate the applicability of adsorption effects for the NVF process.

Pengolahan Air Limbah Tahu Menggunakan Metode Elektrokoagulasi dan Adsorpsi Secara Kontinyu

Tofu wastewater contains a lot of protein therefore it is easily degraded to produce foul odors and harmful gases due to microbes. Protein levels can be reduced through the electrocoagulation method which is equipped with adsorption. The purpose of this study is to reduce the value of turbidity, TSS, and COD in tofu wastewater due to the influence of voltage in the electrocoagulation process which is equipped with an adsorption process. This research was conducted with an electrocoagulation process at a rate of 250L/min with voltage variations of 15, 20, and 24Volt in a 10L tank containing 3 pairs of aluminum (Al) electrodes connected with direct current. The output water from the electrocoagulation process flows into the settling basin and flows into the adsorption tank containing activated carbon adsorbent. Both of these continuous processes were the innovation of this research. Sampling was conducted every 10 minutes for analysis of turbidity, TSS, COD, and pH. The results of the output water analysis from the electrocoagulation process after passing through the precipitation and adsorption processes show that increasing the voltage results in the decrease of turbidity, TSS, and COD values, however, increased efficiency and pH. Thus, a voltage of 24V with a flow rate of 250mL/min resulted in the highest efficiency of the voltage variations (15, 20, and 24V) with a process time of 90 minutes with a turbidity impurity reduction efficiency value of 45.42% with a value of 41.36 NTU from 75.22NTU, TSS 91.42% with a decrease to 1827mg/L from 21288mg/L, and COD 55.56% with a COD value of 9600mg/L from 21600mg/L, and a process output water pH of 4.91, as well as a reduction in aluminum electrode weight of 1.024grams.

ZrBDC-Based Functional Adsorbents for Small-Scale Methane Storage Systems

Metal-organic frameworks (MOF), potentially porous coordination structures, are envisioned for adsorption-based natural gas (ANG) storage, including mobile applications. The factors affecting the performance of the ANG system with a zirconium-based MOF with benzene dicarboxylic acid as a linker (ZrBDC) as an adsorbent were considered: textural properties of the adsorbent and thermal effect arising upon adsorption. The high-density ZrBDC-based pellets were prepared by mechanical compaction of the as-synthesized MOF powder at different pressures from 30 to 240 MPa at 298 K without a binder and mixed with polymer binders: polyvinyl alcohol (PVA) and carboxyl methylcellulose (CMC). The structural investigations revealed that the compaction of ZrBDC with PVA under 30 MPa was optimal to produce the ZrBDC-PVA adsorbent with more than a twofold increase in the packing density and the lowest degradation of the porous structure. The specific total and deliverable volumetric methane storage capacities of the ZrBDC-based adsorbents were evaluated from the experimental data on methane adsorption measured up to 10 MPa and within a temperature range from 253 to 333 K. It was measured experimentally that at 253 K, an 100 mL adsorption tank loaded with the ZrBDC-PVA pellets exhibited the deliverable methane storage capacity of 172 m3(NTP)/m3 when the pressure dropped from 10 to 0.1 MPa. The methane adsorption data for the ZrBDC powder and ZrBDC-PVA pellets were used to calculate the important thermodynamic characteristic of the ZrBDC/CH4 adsorption system—the differential molar isosteric heat of adsorption, which was used to evaluate the state thermodynamic functions: entropy, enthalpy, and heat capacity. The initial heats of methane adsorption in powdered ZrBDC evaluated from the experimental adsorption isosteres were found to be ~19.3 kJ/mol, and then these values in the ZrBDC/CH4 system decreased at different rates during adsorption. In contrast, the heat of methane adsorption onto the ZrBDC-PVA pellets increased from 19.4 kJ/mol to a maximum with a magnitude, width, and position depended on temperature, and then it fell. The behaviors of the thermodynamic state functions of the ZrBDC/CH4 adsorption system were interpreted as a variation in the state of adsorbed molecules determined by a ratio of CH4-CH4 and CH4-ZrBDC interactions. The heat of adsorption was used to calculate the temperature changes of the ANG systems loaded with ZrBDC powder and ZrBDC pellets during methane adsorption under adiabatic conditions; the maximum integrated heat of adsorption was found at 273 K. The maximum temperature changes of the ANG system with the ZrBDC materials during the adsorption (charging) process did not exceed 14 K that are much lower than those reported for the systems loaded with activated carbons. The results obtained are of direct relevance for designing the adsorption-based methane storage systems for the automotive industry, developing new gas-power robotics systems and uncrewed aerial vehicles.

Thermal Management for Hydrogen Charging and Discharging in a Screened Metal-Organic Framework Particle Tank.

Thermal management of H2 gas storage in a tank is crucial for determining the H2 gas deliverable capacity. In this study, a strategy for the design of an excellent comprehensive performance fuel storage tank from the screening of microscopic materials to the design of macroscopic particle adsorption tank performance is proposed. The best metal-organic framework (MOF) for H2 deliverable capacity in a computation-ready experimental MOF database is first screened using a grand canonical Monte Carlo (GCMC) method. An upscale model that combines the finite volume method with GCMC is then established to investigate the H2 charging and discharging processes in a screened best MOF-filled adsorption particle tank that is integrated with a phase-change material (PCM) jacket. The process of the heat and mass transfer in the screened best MOF particle adsorption tank with and without the PCM jacket-inserted metal foam is studied. The results show that the prescreened XAWVUN has the highest gravimetric and considerable volumetric deliverable capacity among 503 MOFs, which can reach up to 23.1 mol·kg-1 and 20.8 kg·m-3 at 298 K and pressures between 35 000 kPa (adsorption pressure) and 160 kPa (desorption pressure), respectively. The H2 deliverable capacity can be maximized by 3.2 and 12.1% for PCM jackets inserted with metal foam in the H2 charging and discharging processes when it is compared with the case without the PCM jacket, respectively. The above study will facilitate the development of new equipment for hydrogen storage.

Experimental Research on the Law of Energy Conversion during CO2 Sequestration in Coal

CO2 sequestration in coal is mainly attributed to adsorption. The adsorption experiments of CO2 were conducted at injection pressures ranging from 1 to 3 MPa on coal samples with five kinds of particle sizes. The fitting degree of four classical adsorption models to experimental adsorption data was systematically compared. The adsorption properties of CO2 were comprehensively discussed. The temperature changes of coal samples at different positions during CO2 adsorption were measured by using the improved adsorption tank, and then the energy conversion law was obtained. The results showed increasing gas injection pressure can effectively increase the adsorption capacity of CO2 on coal samples. The BET equation had the best fitting accuracy for CO2 adsorption on various size coal samples. There was a significant exothermic effect during CO2 adsorption and storage. With the rise of injection pressure, the peak value of the rising temperature of coal samples increased, but the change rate decreased. The maximum temperature rise of coal samples was up to 13.6 °C at 3 MPa, which should be of great concern for the prevention of coal spontaneous combustion. During the sequestration process of CO2, the adsorption resulted in a decrease in coal surface free energy and then partial conversion to heat, leading to the rise of coal temperature. In addition, the CO2 adsorption on the pore surface caused the expansion and deformation of coal.

Comparison of two typical regeneration methods to the spent biological activated carbon in drinking water.

The spent biological activated carbon (BAC) should be disposed properly; regeneration was a better choice. Performances of thermal and ultrasonic regeneration to the BAC with various service time (3years, 5years, and 10years) were compared comprehensively; the recovery of the BAC's pore structure, variation of mechanical hardness, influence of bioactivity, and removal efficiency of typical pollutants in the reuse were examined. The results showed that thermal regeneration was an utterly regeneration, and almost all the pore structure was restored, whose recovery rate was above 90% for BAC used 3years and disfavored by the longer BAC's service time (83% for the BAC used 5years). Ultrasonic regeneration could recover part of the BAC's pores (including micropores) and the restoration mainly focused on the BAC's surface, so the recovery rate was not influenced by the BAC's service time, and the recovery values of specific surface areas and iodine value were kept at 120m2/g and 200mg/g, respectively. In addition, the ultrasonic treatment enhanced the BAC's biological activity even with a significant decrease of the biomass on the BAC. The mechanical hardness of BAC decreased from 95 to 89% for the first regeneration and further to 79% for the second regeneration, whereas relatively lower decrease happened for the ultrasonic regeneration (less than 10% after 5 regeneration cycles). The mass losses in the thermal and ultrasonic regeneration were about 13%, 0.5%, and 25%, 3% for the first and second regeneration, respectively. The thermal-regenerated activated carbon (AC) exhibited excellent adsorption ability, good adherence of biofilm, and maintain higher removal rate for more than 2years, which were similar with that of the fresh AC, but relatively lower removal performance was found. However, the ultrasonic regenerated BAC retained the biodegradation ability, restored the fast-adsorption ability, and the higher removal process lasted about 6months. Taking the regeneration cost, operation, variation of the AC's characteristics, and the removal performance in reuse, ultrasonic regeneration was more suitable for the BAC filter and better used as a regular measure to maintain the higher removal performance, whereas thermal regeneration was more applicable to the activated carbon adsorption tank.

Industrial Application of Non-thermal Plasma (NTP) for Mercury and Dioxin Removal in Flue Gas

At present, there is an urgent demand for mercury and dioxin pollution control technology, internationally. It is necessary to find a solution other than the activated carbon adsorption process. In recent years, our self-developed low temperature plasma coupling system has been applied for mercury and dioxin removal in the flue gas, the system is composed of corona discharge plasma reactor and ceramic nano-material adsorption tank. The parameters of the plasma are 35-40kV, 400-450A, 1000Hz. The saturated adsorption capacity of ceramic nano-materials for Hg2+ is more than 5156μ g(Hg2+)/g. Pilot plant testes have been conducted in several industries, including collaborative disposal of cement kiln, medical waste incineration, recovery of waste mercury catalyst, recycling of waste fluorescent tubes, and achieved ideal result (Hg removal efficiency > 95%). It is expected to be an economical and efficient technology for mercury and dioxin removal, with great promotion value and social significance.

Improvement of adsorption-thermal nitrogen cycle-shunt condensation organic gas recovery technology

Based on the adsorption-thermal nitrogen cycle-shunt condensation organic gas recovery technology, this paper investigates the existing adsorption theories and engineering practices and studies the desorption part of this recovery process using a combination of theory and experiment so as to propose suggestions for improvements from the viewpoint of desorption rate and desorption effect. Based on the experimental conditions of this paper, when the cyclic desorption turndown ratio (the ratio of clean gas to total circulation gas) λ equals 0.5, it is more advantageous to increase the desorption rate of volatile organic compounds. Continuing to increase λ will increase energy consumption in actual engineering, but has no significant effect on either the desorption rate of activated carbon in the adsorption tank or the desorption effect. This provides reliable data and methods for efficient operation of this technology and energy saving.

Experimental investigation of CO2 separation by adsorption methods in natural gas purification

CO2 separation for natural gas purification by the adsorption method was studied in detail using volumetric adsorption apparatus. The crystalline phase and microstructure of the experimental sample were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Micromeritics ASAP 2020 instrument. The XRD pattern proves that the experimental sample consists of 13X zeolites. The SEM images show that the 13X zeolites expose a large number of micro-channels on the surface of the particles. The microporous volume is 0.22cm3(STP)/g. The ideal swing frequency for the adsorption tank can improve the adsorption performance of an adsorbent compared with a static adsorption tank. The pure CO2 adsorption experimental data agrees well with the extended Langmuir model. The Langmuir-Freundlich model correlates the CO2/CH4 mixture adsorption experimental data fairly well. The relative errors between the simulated results and the experimental data are very little, which indicates that these fitted models are correct. The average selectivity of CO2/CH4 in a static and swing adsorption tank are, respectively, 3.57 and 3.93, considerably higher than 1, indicating preferential CO2 adsorption over CH4 in CO2/CH4 mixtures. This also shows that the swing can improve CO2 separation for natural gas purification. For the three types of motion status, the temperature of the adsorption tank increased in the order swing 2>swing1>static state for pure CO2 adsorption in 13X zeolites. The temperature variation decreased as the pressure increased. The amplitude and time of temperature variations in the adsorption tank can explain the adsorption capacity and adsorption speed. This research will improve the efficiency of offshore natural gas exploitation, and will affect the optimization of energy structures.

Applications of organic phase change materials embedded in adsorbents for controlling heat produced by charging and discharging natural gas

This paper studied the thermal effect resulting from the adsorption of natural gas on both charge and discharge on an absorbed storage system using a phase change material (PCM) as heat exchanger. A kind of organic PCM whose phase change heat is 153 J/g, measured by DSC,consisting of decanoic acid and lauric acid was prepared. The PCM was used to control the heat effect during the adsorption and desorption of natural gas. By adding the volume ratio of 6.10 % of the PCM into the adsorption tank, the temperature change can be reduced 21.8 °C during adsorption and can be increased 22.7 °C during desorption. Meanwhile, the delivered natural gas volume was increased 39.4 % with the use of the PCM compared to the case without PCM for a 0–3.5 MPa of pressure swing. Application of this kind of cheap PCM in the adsorption tank is an effective method to reduce the adverse effects of adsorption heat and thereby enhance storage capacity and delivery.

Assessment of options for economic processing of preg-robbing gold ores

One of the challenges facing the gold industry in the twenty-first century is the continuing need to identify new reserves of economically treatable ores. Discoveries of large, metallurgically simple orebodies are becoming increasingly rarer, forcing companies to investigate options for the processing of ores which may present recovery, economic and/or environmental issues, requiring innovative approaches to their treatment. Ores which contain naturally occurring carbonaceous material (‘preg-robbing ores’) is an example of one such ore type. Newmont’s Jundee operation contains zones of carbonaceous ore within the oxidised ore body. A program consisting of detailed laboratory work and extensive plant trials has been undertaken to assess the options of the processing of this material. Laboratory tests demonstrated the advantage of carbon-in-leach (CIL) over direct cyanide leaching and carbon-in-pulp (CIP) for treatment of these ores. The laboratory program identified several factors which would enhance overall gold recoveries when preg-robbing ore was being processed, including: keeping preg-robbing ore separate from non-graphitic ore, maximising gravity recovery and ensuring the plant operates in ‘pure’ CIL mode i.e. no leaching before first adsorption tank. Plant trials were undertaken to assess the economic sustainability of treating moderate preg-robbing ores through a modified gravity/leach/adsorption circuit. Results indicated that where good operational control of the circuit was maintained to ensure high gravity recovery, minimal leaching prior to carbon contact and maintenance of good, active carbon inventory, then acceptable and sustainable overall gold recoveries could be obtained. However, plant trials did not produce gold recovery as high as laboratory tests. Using these relatively simple plant modifications potentially allows a plant to treat ores with preg-robbing index (PRI) values up to 1. When PRI values rise to 1·3–1·6 leach recoveries can drop from >85 to <40%, indicating a more intensive approach may be required, including kerosene addition and higher carbon inventories and activities.

Optimization Design of Experimental Devices of Carbon Dioxide Removal by Membrane Method

Basing on the calculation and analysis, the thesis has carried on the optimization design to the arrangement way of the carbon dioxide membrane contactor and the way between the original fluid pond and the adsorption tank. From the calculation results, if the vertical space is sufficient, membrane contactors can take vertical layout (a). Membrane contactor vertical layout does not require additional water pump, the economy is high. However, if taking into account the ease of operation, and the lack of vertical space, the level of membrane contactor layout should be taken. The level of membrane contactor layout needs the pump head minimum in the same condition. In addition, basing on the calculation, no matter what kind of layout membrane contactor, the vertical layout is better than the level layout in the arrangement way between the original fluid pond and the adsorption tank. The vertical layout arrangement between the original fluid pond and the adsorption tank, which needs the pump head minimum, the economy is high.

Studies on Micro-Polluted Source Water Treatment by Ozone Combined Processes

According to the water quality characteristics, micro-polluted source water treatment by ozone combined processes. The results show that the average removal efficiencies of algae, CODMn, NH4+-N, turbidity, chromaticity by bio-pretreatment filter are 72.0%, 14.5%, 80.5%, 58.6% ,26.0%, respectively; while the whole average removal efficiencies by pre-ozonation tank following bio-pretreatment filter had increased at the different dosages of ozone, such as algae 12.0%, CODMn 19.5% ,NH4+-N 7.5%, turbidity 10.9%, chromaticity 34.5%, respectively; and the optimal dosages of ozone are between 0.7 and 1.5mg/L. Furthermore, compared with the conventional water treatment process, all kinds of combined water treatment processes are better than the conventional one, of which the combined process Ⅲ with granular activated carbon (GAC) adsorption tank is obviously the best, all the average removal efficiencies of algae, CODMn, NH4+-N, turbidity, chromaticity can reach 82%, while whose operation expenditure is higher than any others, so it should be considered comprehensively in the practice.

The Experiment of Gas Adsorption and Desorption Under the Action of High Tempertature and High Pressure Water

Through the determination test for the quantity of gas adsorption and desorption under different temperature conditions, the law of influence of the temperature change on the adsorption and desorption of coal and methane in constant pressure condition was researched. The paradoxical law highly emphasizes that the increase of gas desorption quantity due to temperature rise and part of water adsorbing coal under the effect of high pressure water together affect the quantity of gas adsorption and desorption. In the end, we can obtain the law of desorption seepage of the coal seam gas when the coal was placed under different water contents and different temperature. Making use of the adsorption and desorption experiment system of the coal under constant pressure, the temperature control module was added to the osmoscope, thus, the desorption quantity of the coal sample in different temperature and high pressure water was measured. The result shows that, when the adsorption tank is under the same pressure, desorption quantity of the coal will increase with the temperature; if the same coal sample adsorbs twice, the adsorption quantity is bigger than the former. When it is affected by high pressure water, the adsorption rate of the coal to the gas will reduce. If the same coal sample experiences high pressure water twice, the water quantity injected in the second time is larger; and the adsorption and desorption quantity is different, the second one is a little larger than the first one. The initial temperature is also higher when it begins to desorb. When the coal is affected by high pressure water, the water adsorbed influences the gas desorption and seepage.

Contact-Adsorption-Regeneration-Stabilization Process for the Treatment of Municipal Wastewater

In this work, the application of the contact-adsorption-regeneration-stabilization activated sludge process for the municipal wastewater treatment was investigated by using continuous experiments coupled with adsorption batch experiments. The process optimization for performance evaluation was studied. The obtained appropriate operational parameters of recycle ratio, hydraulic retention time (HRT) of the regeneration tank, HRT of the adsorption tank and solids retention time (SRT) of the system were 40%, 2 h, 30 min, and 6 d, respectively. Adsorptive kinetics and equilibrium were investigated with batch experiments of adsorption. The results showed that the activated sludge concentration was in a positive proportion to its adsorptive capability, but that temperature was in an inverse proportion to the adsorptive capability. Adsorptive equilibrium was reached within 15 min. In addition, the equilibrium data fitted well to both the Freundlich and Langmuir adsorption models.

Ultrasound Attenuation for Controlling Carbon Concentration in Gold Adsorption Tanks

An instrument has been developed for the accurate determination of carbon concentration in a gold adsorption tank. The DEBEX Carbon Concentration Meter (С Meter™) uses high-frequency ultrasound attenuation to measure the carbon concentration. It can be connected to a control system to automate the carbon transfer process.

A regenerable carbon dioxide removal and oxygen recovery system for the Japanese experiment module

The Japanese Space Station Program is now under Phase B study by the National Space Development Agency of Japan in participation with the U.S. Space Station Program. A Japanese Space Station participation will be a dedicated pressurized module to be attached to the U.S. Space Station, and is called Japanese Experiment Module (JEM). Astronaut scientists will conduct various experimental operations there. Thus an environment control and life support system is required. Regenerable carbon dioxide removal and collection technique as well as oxygen recovery technique has been studied and investigated for several years. A regenerable carbon dioxide removal subsystem using steam desorbed solid amine and an oxygen recovery subsystem using Sabatier methane cracking have a good possibility for the application to the Japanese Experiment Module. Basic performance characteristics of the carbon dioxide removal and oxygen recovery subsystem are presented according to the results of a fundamental performance test program. The trace contaminant removal process is also investigated and discussed. The solvent recovery plant for the regeneration of various industrial solvents, such as hydrocarbons, alcohols and so on, utilizes the multi-bed solvent adsorption and steam desorption process, which is very similar to the carbon dioxide removal subsystem. Therefore, to develop essential components including adsorption tank (bed), condensor, process controller and energy saving system, the technology obtained from the experience to construct solvent recovery plant can be easily and effectively applicable to the carbon dioxide removal subsystem. The energy saving efficiency is evaluated for blower power reduction, steam reduction and waste heat utilization technique. According to the above background, the entire environment control and life support system for the Japanese Experiment Module including the carbon dioxide removal and oxygen recovery subsystem is evaluated and proposed.

Liquid-to-particle mass transfer in a stirred batch adsorption tank with non-linear isotherm.

Liquid-to-particle mass transfer in a stirred batch adsorption tank with non-linear isotherm.