TSA Process Research Articles

Adsorption study of CO2/CH4 and CO2/N2 binary mixtures on titanosilicates ETS-10 and SrETS-10; industrial application aspects

Despite the outstanding features of the titanosilicate ETS-10 and some studies done on CO2 adsorption so far, there is a lack of coherent information to evaluate its potential industrial application in CO2 separation from natural gas and flue gas. In this work, ETS-10 and SrETS-10 were synthesized and characterized by PXRD, SEM, DTA, EDX, and BET. Pure gas adsorption isotherms of CO2, CH4, and N2 at 298 K were obtained by the constant-volume method. The obtained adsorption data were fitted with Langmuir and UNILAN isotherm models. The CO2/CH4 selectivity (yCO2 = 0.05) predicted by Ideal Adsorption Solution Theory (IAST) was 67.54 and 35.65 for ETS-10 and SrETS-10, respectively, while the CO2/N2 selectivity (yCO2 = 0.04) was 94.64 and 99.94. The Pseudo-Nth-Order (PNO) and micropore diffusion model were used to evaluate the CO2 adsorption kinetics and diffusivity of the adsorbents. The results showed that both ETS-10 and SrETS-10 exhibited fast kinetics for CO2 adsorption, but SrETS-10 had a slightly smaller diffusion coefficient (DC/rC2 = 0.01494 and 0.01458 s−1 for ETS-10 and SrETS-10, respectively) resulting in a slower adsorption rate than ETS-10. The regenerability of ETS-10 and SrETS-10 was studied and it was found that for ETS-10 about 79.07% and 96.32% of the capacity can be regenerated by applying vacuum and heating, respectively and also 79.67% of the SrETS-10 capacity can also be regenerated by applying vacuum. From the results of this work with an approach of industrial application, it was concluded that ETS-10 and SrETS-10 can be used in a combined PSA and TSA process for CO2 separation.

Novel dynamic light scattering immunosensor for prostate specific antigens based upon dual-tyramine signal amplification strategy

The sensitive detection of biomarkers is crucial for the early diagnosis, treatment, and improvement of the quality of life of patients. A novel dynamic light scattering-dual tyramine signal amplification strategy (DLS-dTSA) was constructed to detect prostate-specific antigen (PSA). The Oligo 1 was first immobilized in a 96-well plate for PSA capture. Afterwards, horseradish peroxidase (HRP) and Oligo 2 functionalized AuNPs (HRP-Au NPs-Oligo 2) bound to Oligo 1 through DNA hybridization. In the presence of hydrogen peroxide (H2O2), tyramine could be converted into a transient radical intermediate by HRP, leading to the aggregation of tyramine and HRP-labeled AuNPs (tyramine-AuNPs-HRP) near HRP-AuNPs-Oligo 2, triggering the first TSA process. Later, the PSA was added into the 96-well plate, to specifically recognize aptamer and thus depart the Au-aggregate from the 96-well plate. Then H2O2 was added to the Au-aggregate solution, triggering the free Au-aggregate to gather again, realizing the second TSA amplification. The average diameter of Au NPs increased linearly with the concentration of PSA during the range of 0.0001 – 1000 ng mL−1, and the limit of detection was 0.033 pg mL−1. Moreover, this strategy has been used to analyze PSA in human serum samples successfully, demonstrating the potential application of the proposed method for rapid clinical and early clinical diagnosis of prostate cancer in vitro.

Performance study on an energy-efficient TSA air-purification process utilizing compression heat regeneration

A novel compression heat regeneration TSA process is disclosed in this paper, which aims to reduce the regeneration energy consumption of the raw air purifier in the air separation process. Since air separation is an energy-intensive process accounting for a significant proportion (about 5 %) of China's total electricity consumption, this new process holds great significance in energy conservation. Distinguishing from traditional processes, the new one integrates components such as a compressor, a regenerator, and an expander to meet the regeneration heat requirements of the purifier with minimal electrical energy consumption. It also recovers the waste heat from the tail gas to enhance the expander’s power generation, thereby realizing efficient and comprehensive energy utilization. Mathematical models have been established for components such as the adsorber, compressor, and expander, and simulations have been conducted based on actual data from an industrial-grade purifier. Consequently, historical parameter curves and bed profiles at the inlet and outlet of the adsorber have been obtained, providing insights into the purification performance and regeneration effectiveness of the new process. Furthermore, the inlet and outlet parameters, as well as the power consumption of the compressor and expander, have been determined. The temperature bed profiles and temperature history curves at the inlet and outlet of the regenerator have also been obtained. Subsequently, a comparison has been made between the new and traditional processes regarding energy consumption, and an economic assessment of the new process has been conducted based on its energy-saving potential. The following conclusions have been drawn through comparative analysis: (1) Compared to the traditional process, the new process can save approximately 51.6 % of electrical energy; (2) The payback period for retrofitting the traditional process to the new one is approximately 1.93 years.

Experimental and Numerical Investigations on the Adsorption/Desorption Performance of Low-Concentration VOCs over H-ZSM-5 with Different SiO2/Al2O3 Ratios

A mechanistic study was presented on the effect of the SiO2/Al2O3 ratio (SAR) on the adsorption/desorption behaviors of low-concentration volatile organic compounds (VOCs) over H-ZSM-5. In this study, n-hexane, toluene, and ethyl acetate were used as the probe VOC molecules. And their adsorption isotherms on different H-ZSM-5 (SARs = 25, 130, 300, and 470) were collected at various temperatures (30, 40, and 50 °C). Results showed that high SARs were conducive to adsorption, but the desorption efficiency was imperfect. The dependence between an absorbent and VOCs was divergent. Higher adsorption capacity for toluene (87.54 mg·g–1) and ethyl acetate (150.74 mg·g–1) was achieved on H-ZSM-5(470), while H-ZSM-5(300) owned higher adsorption capacity for n-hexane (107.24 mg·g–1). Based on the adsorption isotherms and breakthrough curves, the equilibrium and kinetic parameters were obtained based on the Langmuir model. Then, a rigorous temperature swing desorption (TSA) model was established to predict the evolution of temperature and VOC concentration along the axial adsorption bed. And the simulation results of the TSA process agreed well with the experimental data.

Rapid temperature swing adsorption using microwave regeneration for carbon capture

The use of microwave heating for the thermal regeneration of a porous carbon adsorbent in adsorptive carbon capture was evaluated. In this Microwave Swing Adsorption (MSA) process, a multimode microwave oven has been used to accelerate the desorption of CO2 after the adsorption of a CO2 / N2 (15/85 v/v) mixture. Starting from a commercial activated carbon (AC) material (MSP-20X), sorbent extrudates were prepared and loaded in a Teflon column. The heating of the sorbent bed inside the microwave (MW) cavity was characterised at different locations. Although the adsorption bed is not heated uniformly due to hot spots in the multimode MW cavity, flowing a purge gas reduces the non-uniform heating during the regeneration step. This study also reports that MSA regeneration achieves extremely fast total desorption (in 56 to 79 s), the quickest regeneration reported up to date in MSA, and very rapid desorption rates allowing swift adsorption–desorption cycles. This fast desorption is associated with the extremely high heating rates achieved (100 to 400 °C/min). We show that the desorption rate is faster when using higher powers at practically identical MW energy inputs. Complete CO2 desorption can be achieved at slightly longer durations when using 2-step MW heating. When comparing the MSA results with a reference TSA process, MSA outperforms TSA, due to the higher heating rates achieved by MSA. During eleven adsorption–desorption cycles, it is evidenced that the MSA process can regenerate the adsorption bed at a high reproducibility. The microporosity of the material remained intact during the MSA, revealing that localised heating and the high heating rates are not damaging the sorbent material.

A Comparative Assessment of Emerging Solvents and Adsorbents for Mitigating CO2 Emissions From the Industrial Sector by Using Molecular Modeling Tools

Some specific examples are presented showing the possibilities offered by molecular modelling tools to obtain relevant data at process conditions while also gaining molecular insights on the techniques used for CO2 capture and separation. Two different technologies, absorption with amine-based systems and adsorption on porous materials, were explored, using the molecular-based equation of state, soft-SAFT, and Grand Canonical Monte Carlo simulations, respectively. The aqueous monoethanolamine (MEA) system was used as the benchmark for absorption and compared to the performance of eight alternative amine-based systems, while sixteen adsorbents belonging to different families (zeolites, Metal Organic Frameworks, silicas and activated carbons), bare or functionalized with alkylamines, were investigated for the separation of CO2 by adsorption. In addition to obtaining molecular information on the CO2 capture process, the models were further used to examine the CO2 capture performance in terms of cyclic working capacity and energy index as key performance indicators, allowing the identification of promising systems that can improve the current ones to be further evaluated for separation in non-power industries. Results show that for the same total amine mass concentration, non-aqueous amine solvents possess a 5–10% reduction in cyclic working capacity, with a 10-30% decrease in the energy index compared to their aqueous counterparts, due to lower heat of vaporization and sensible heat. It has also been obtained that M-MOF-74 and zeolites NaX and NaY structures offer the best results for adsorption in TSA processes. Some adsorbent structures achieved similar values of energy requirement to the ones obtained for alternative amine-based systems (2-2.5 MJ∙kgCO2-1), although the disadvantage of the TSA process versus absorption should be taken into account. These results confirm the reliability of the molecular modelling approach as an attractive and valuable screening tool for CO2 capture and separation processes.

Production of MOF Adsorbent Spheres and Comparison of Their Performance with Zeolite 13X in a Moving-Bed TSA Process for Postcombustion CO2 Capture

Well-shaped 300–700 μm spheres of aggregated metal–organic framework CPO-27-Ni crystallites have been produced using a spray-granulation method with cross-bonded alginate as the binder. The spheres...

Water vapor harvesting by a (P)TSA process with MIL-125(Ti)_NH2 as adsorbent

The potential of the MIL-125(Ti)_NH2 for water (H2O) capture from air is assessed in the present study. To achieve this goal, the adsorption affinity of the material towards different adsorbates, and its subsequent regeneration in adsorption/desorption cycles, were evaluated. Adsorption equilibrium isotherms were measured in a temperature range between 283 and 323 K and pressure between 0 and 7 bar. Water vapor presented isotherms of Type V and were fitted by applying the Cooperative Multimolecular Sorption (CMMS) model and Polanyi’s theory model. Breakthrough experiments of water vapor corroborated that the adsorption equilibrium isotherm is of Type V. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis revealed a high capability of regeneration during the adsorption/desorption cycles. The pressure-temperature swing adsorption (P)TSA proposed process shows a maximum productivity of 320 L·day−1·ton−1, considering a regeneration temperature of 373 K, and condensate the outlet stream during the regeneration step at 283 K.

A comprehensive performance evaluation of temperature swing adsorption for post-combustion carbon dioxide capture

Carbon dioxide capture from the post-combustion flue gas via temperature swing adsorption is supposed to be a valid technology to mitigate carbon emissions. With regard to the adsorbent development and process improvement, the technologies of temperature swing adsorption for post-combustion carbon dioxide capture have been reviewed and compared in terms of fixed bed, fluidized bed and moving bed. A comprehensive evaluation framework of fixed-bed temperature swing adsorption for CO2 capture has been established. In a four-step fixed-bed cycle, a shortcut model has been utilized. Four typical adsorbent materials, such as activated carbon, zeolite 13X, zeolite NaUSY and Mg-MOF-74, have been chosen in this assessment. The comparative study has been conducted under the same operating conditions, from four aspects using eight performance indicators. Results indicate that Mg-MOF-74 and zeolite 13X reveal excellent performance among the four selected adsorbents. Thereinto, Mg-MOF-74 performs well at four indicators including purity, productivity, specific thermal energy consumption and second-law efficiency; zeolite 13X excels in the other four indicators such as selectivity, recovery, minimum separation work and capture cost. Future work will complete a thorough assessment criterion in evaluating the TSA process for CO2 capture.

A novel temperature swing adsorption process for natural gas purification, Part II: Performance assessment

A novel temperature swing adsorption-based natural gas purification cycle using a monolith consisting of adsorbent-coated microchannels is investigated in this two-part study. In the accompanying paper, Part I, the development of a full process simulation model, and selection of geometric parameters and adsorbent and heat transfer fluid were reported. This paper, Part II, develops a comprehensive performance map of the process that involves determination of ranges of product purity, CH4 recovery and process capacity, and energy requirements. The TSA-based process in the present work is found to produce up to two orders of magnitude more purified product than that from adsorbent bed-based PSA processes reported in the literature, while product purity and CH4 recovery values remain competitive. This concept is also found to reduce the system footprint by 82% when compared with a TSA process that uses separate microchannels for the flow of working and coupling fluids. Additionally, methods for reducing process energy requirements are considered, along with enhancement of product purity via a staged purification scheme. The energy requirement for the process is found to be lower than that for MEA absorption systems, indicating the potential for large-scale installations based on this process.

Evaluating the Feasibility of a TSA Process Based on Steam Stripping in Combination with Structured Carbon Adsorbents To Capture CO2 from a Coal Power Plant

The present work evaluates the feasibility to capture at least 85% of the CO2 emitted by an advanced supercritical pulverized coal power plant of 800 MWe, delivering a CO2 product with a purity of 95% (dry basis) or higher, using an adsorption-based postcombustion capture process based on carbon honeycomb monoliths regenerated by steam stripping. Process performance has been evaluated through the dynamic simulation of the cyclic adsorption process. The fixed bed adsorption model, which was validated against experimental results, is based on the mass, momentum, and energy conservation equations, and it accounts for competitive adsorption between the three main flue gas components: N2, CO2, and H2O. The evaluated TSA process meets the targets for the capture rate and product purity, with a heat duty of 3.59 MJ kg–1 CO2, which is close to the specific reboiler duty of the benchmark amine-based absorption process. Materials and process development will lead to lower duties. A sensitivity analysis was carried ...

A Dynamic Time-slot Assignment for Ground Wireless Sensor Network

This paper is on the background of the applied communications of automated vehicle in the multi-hop environment. The paper provides a dynamic time-slot assignment protocol for the ground wireless sensor network (WSN), based on TDMA. By interacting of the two-hop neighboring nodes information, the protocol finishes the dynamic time-slot assignment, realizes the efficient and fair sharing of channel, reduces the transfer delay of the end-to-end burst data, meets the communication demand of assignment on-demand in WSN, and prolongs the life-time of the network with the virtual backbone mechanism. The theoretical analysis and simulation results showed that the protocol provided has better adaptability for the burst network services and topological variation, comparing to the traditional static mac layer protocol in the TDMA system. multiple address (TDMA), automated vehicle 1. Background WSN has widely used in various fields, especially in the military field. It is well suited to use in the wretched battlefield environment, including monitoring our forces, materials and equipment, keeping watch over the conflict zones, detecting the topography and defensive of the enemy, aiming the targets, assessing the damage, detecting the nuclear, biological and chemical attacks. WSN on the ground is disposed into three parts: the lowest part is the smallest and lowest power consumption attended sensor, the second part is the directional sensor which could assess the azimuth and the third part is the confirmed sensor which has a imaging ability. The first two parts only need slow communications (kbps) between each other and the communication distance is 100-400 meters. The confirmed sensor in the third part need two-speed or two transceivers (Mbps), the one is responsible for the communication with the lower node and the other one is responsible for the communication with the directorial node in a distance which could not exceed 10km. Based on the communication of the ground sensor by using unmanned vehicle in mobile multi-hop, a MAC protocols for the ground wireless network is designed, a TDMA-based dynamic TSA protocol is proposed, this protocol can complete the TSA process by the communication between two neighboring nodes, which can realize the sharing of the high-quality and fair-minded signal path, fulfilling the demand to distribute the communication according to need for the ground wireless network at the same time. This review is followed by an introduction. A brief summary of some of the relevant concepts is presented in Section 2.Section 3 demonstrates the protocol design. Section 4 is the theoretical performance study of the protocol. In Section 5, we discuss the preliminary results of a simulation study. Finally, conclusions and future work are summarized.

What will the small district general hospital look like in the future?

The Mid Staffordshire NHS Foundation Trust was de-licensed and services transferred to two other acute providers on 1 November 2014. The very troubled history of the trust is well documented, and it had been the subject of many reviews and reports, namely: Francis (2013) , Edwards (2012) , Colin-Thome (2009) and Alberti (2009) . While the future of the district general hospital (DGH) has been debated at length, few health economies have significantly altered the distribution of services or ‘clinical model’ of a DGH to secure the longer term sustainability of services. The Trust Special Administration process at Mid Staffordshire NHS Foundation Trust has developed a clinical model which addresses many of the challenges faced by small hospitals. The TSA process involved a full economic review of a range of options including a value for money assessment, however this case study describes the approach taken to developing the clinical model, the outcome achieved and what can be learned by others.

Intensification of the temperature-swing adsorption process with a heat pump for the recovery of dichloromethane

The temperature-swing adsorption process (TSA) is a widely used process for solvent recovery. Steam or a heated gas is used for the desorption of organic pollutants from activated carbons. This study aims to show the efficiency of coupling the TSA process with a heat pump. Hence, the adsorption column was cooled down whereas the column under regeneration was warmed by the heat pump. An experimental unit was designed and experiments were conducted with dichloromethane. The advantages of coupling the TSA process with a heat pump are twofold: the first benefit was for the adsorption step whose efficiency was increased. The decrease of temperature inside the fixed bed enabled a significant increase of breakthrough times (+30% on average). The second benefit of using the heat pump during regeneration cycle is the warming of the activated carbon bed prior to steam desorption. Temperatures up to 45°C were measured during desorption when using the heat pump alone. Experimentally, the results have shown an interesting recovery efficiency (up to 71%) during dichloromethane desorption if using only the heat pump. Numerical simulations, via the software ProSim DAC, predicted the expected process behaviors for dichloromethane on a larger scale: a TSA unit containing 15t of activated carbon. The results showed that the regeneration rate was not totally sufficient, 38.5%, and the use of a heat pump alone was not able to ensure the desorption of the VOC. Although the heap pump by itself was not sufficient to ensure the regeneration, the combination with the steam desorption shed light on new perspectives for the reduction of energy consumption.

Experimental and modeling investigation on post-combustion carbon dioxide capture using zeolite 13X-APG by hybrid VTSA process

Zeolite 13X-APG with Si/Al ratio of 1.23 supplied by UOP (China) was evaluated for capturing the low concentration CO2 from flue gas. The adsorption equilibrium isotherms of CO2 and N2 on this adsorbent were measured at various temperatures (303, 333, 363, 393)K with 0–1bar range of pressure and the experimental data were fitted by the multi-site Langmuir model. Compared with the conventional NaX zeolite, 13X-APG zeolite has an excellent adsorption capacity to CO2, especially at low CO2 partial pressure. The adsorbent is more selective to CO2 in the flue gas. The breakthrough experiments of CO2 and N2 in the column packed with zeolite 13X-APG pellets have been studied. A mathematical model based on the bi-LDF approximation for mass transfer, taking into account the energy and momentum balances, have been employed in the simulation of breakthrough curves in order to obtain the adsorption kinetic parameters of CO2 and N2, respectively. The experimental and theoretical results of a six-step hybrid VTSA process, as well as four-step VSA and five-step TSA process were presented for CO2 capture at ambient temperature and ambient pressure from the simulated flue gas (85% N2 and 15% CO2), and the feasibility and efficiency of VTSA process were analyzed. The regeneration conditions of VTSA process became more gentle when compared with the cases in both VSA and TSA processes, and it would be a saving power-energy consumption process for post-combustion CO2 capture if it was retrofitted to the existed power plants with the utilization of the lower grade heating/cooling source.

The downsizing of a TSA system for an air purification unit using a high flow rate method

A high flow rate type air purification unit to reduce the size of adsorption vessel was developed. The setting area of air purification unit and the cost of adsorption vessel were reduced to 65% and 70% respectively. The downsizing was achieved by the way that a mass transfer zone (MTZ) was formed in the whole region of adsorbent layer and by the development of adsorbent for the high flow rate process. As regards the adsorbent, the adsorption performance to realize the process was investigated. Then the adsorbent which has larger size and higher adsorption performance was developed and TSA process experiment was carried out. As the result, the realization of the high flow rate process was made sure experimentally.

Amines immobilized on a solid support for postcombustion CO2 capture–A preliminary analysis of the performance in a VSA or TSA process based on the adsorption isotherms and kinetic data

Abstract A series of different amines was immobilized on a silica support by grafting or impregnation and tested for CO 2 adsorption in simulated flue gases. This paper compares the adsorption isotherms and the cyclic adsorption capacities of these materials. Furthermore, we estimate the diffusion rate of CO 2 from simulations of the breakthrough curves and discuss some aspects of the design of a potential adsorption process for CO 2 capture.

Experimental Investigation on CO2 Post−Combustion Capture by Indirect Thermal Swing Adsorption Using 13X and 5A Zeolites

Experimental results of CO2 post-combustion capture for a TSA process including an internal heat-exchanger (indirect heating/cooling) are presented. The comparative experimental study is carried out on 13X and 5A zeolites, with a mixture 90% N2−10% CO2 modeling the flue gas. With 5A zeolite having given the best performances, we tested it with various operating conditions including one with nitrogen purge during desorption. This one showed a good compromise between CO2 capture rate, purity of the desorbate, volumetric productivity, and specific-heat consumption. We obtained a volumetric productivity of 37 kgCO2/m3ads·h and a specific-heat consumption of 6 MJ/kgCO2 at our laboratory scale and 4.5 MJ/kgCO2 for the adiabatic estimate (in the same order of magnitude as those obtained industrially with the reference MEA amine process). These results are promising because our process is not optimized yet and the scale-up on an industrial version involves a reduction in specific-heat consumption.

Electrothermal Desorption in an Annular—Radial Flow—ACFC Adsorber—Mathematical Modeling

A mathematical model of an annular, radial-flow adsorber with the possibility of electroresistive heating of the adsorbent bed has been postulated. The model consists of a set of coupled nonlinear PDEs, ODEs and algebraic equations (material and energy balances for the gas and solid in the adsorbent bed and for the gas in the inlet and in the outlet tube, plus equilibrium relation, criterial equations etc.). The model was solved numerically, using the method of orthogonal collocation for space discretization. It can be used for simulation of adsorption, desorption and TSA processes (cyclic adsorption-desorption). The simulation was used for investigation of the influence of the main process parameters and optimization of the TSA process.

A TSA process with indirect heating and cooling: parametric analysis and scaling-up to practical sizes

The performances of a recently developed TSA process for gaseous pollutant treatment, based on indirect heating and cooling by means of an internal heat-exchanger, have been investigated both numerically and experimentally. Heating is carried out by condensing steam, and cooling by water circulation. The cycle performances are usually better than those of competing processes, but with increased heat consumption. The sensitivity of the performances to the regeneration temperature and purge flow rates is discussed. Lastly, it is shown that in the conditions of an adsorber scaled-up to a typical practical size including a mass of adsorbent 1000 times higher than in the laboratory column, the specific heat consumption is in the same range as conventional TSA processes.