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To determine the effects of nonventilatory CO2 transfer on breathing pattern, we monitored breathing in 7 patients with renal failure undergoing hemodialysis. A respiratory inductance pleth

Summary A pilot CO2 recovery system was installed in a major west Texas field to confirm the operation and performance of commercial-size coated hollow-fiber membrane gas separators. Data were gathered to verify predicted membrane performance on the basis of earlier demonstration tests. Such parameters as feed pressure, temperature, and CO2 content in the feed gas were evaluated. Removal of CO2 from a casinghead gas stream containing 40 to 80 vol% CO2 was successfully demonstrated with minimum pretreatment of the feed gas. The data taken compared favorably with predicted performance curves based on earlier demonstration unit results.

An overview into the development of a carbon dioxide removal plant for submarines to meet the U.S. Navy's operational and safety requirements is presented. The monoethanolamine -CO2 removal process and parametric studies to reduce atmospheric CO2 levels in submarines to 0.5% and possibly 0.2% are discussed.

Vessels suitable for storing mushrooms [Agaricus bisporus (Lange) Singe] at absolute pressures to 35 atm were constructed from 43 liter (1A) gas cylinders and plumbed for conducting static or continuous-flow experiments. Neither pressurization nor gradual depressurization over 6 hr injured mushrooms. Pressure did not affect respiration, but significantly reduced moisture loss during storage. Mushrooms depleted O2 to very low levels and showed high tolerance to CO2. Pressure was used to safely increase CO partial pressure (p) 35-fold. At 0.035p, CO reduced mushroom browning but not respiration. A completely autonomous storage system with CO2 removal and automatic O2, replenishment was developed.

Use of the total-sample method was extended to measurement of the leakage of carbon dioxide through an oil-filled knockout trap in a large synthetic ammonia plant. Approximately 1 mc of C14O2 was injected into the plant, and gas samples were withdrawn from points ahead of and beyond the trap. The C14O2 was recovered from the samples and counted in a liquid scintillation counter. The high sensitivity of the method is illustrated by the detection of approximately 1 μc of C14 in a gas stream flowing at over 6 × 106 standard ft3/hr. The trap was shown to be 99.9 percent efficient in CO2 removal.

The rates of hemoglobin saturation and carbon dioxide reduction in blood flowing in a curved channel membrane exchanger were studied theoretically by considering the fluid-limited process and the wall-limited process. The fluid-limited process was studied for laminar flows with and without secondary circulations. The relatively nontraumatic centrifugally induced circulations in the curved channel can reduce the required channel length to less than 1/500 that required for unperturbed flow. Such improvement, however, is practical only if very permeable membranes are available. If the PO2 = 715 mm. Hg and PCO2 = 0 mm. Hg at the walls, the fluid-limited analyses show oxygenation to be the slower process and the wall-limited analyses indicate CO2 removal to be the limiting process. If the best available silicone rubber membranes are used, the process will be fluid limited for the unperturbed flow and wall limited for the flow with secondary circulations.

Hilliard [M.D. Hilliard, A predictive thermodynamic model for an aqueous blend of potassium carbonate, piperazine, and monoethanolamine for carbon dioxide capture from flue gas, Ph.D. Dissertation, The University of Texas at Austin, Austin, Texas, 2008.] completed several thermodynamic models in Aspen Plus ® for modeling CO 2 removal with amine solvents, including MEA- H 2 O- CO 2 . This solvent was selected to make a system model for CO 2 removal by absorption/stripping. Both the absorber and the stripper used RateSepTM to rigorously calculate mass transfer rates. The accuracy of the new model was assessed using a recent pilot plant run with 35 wt% MEA. Absorber loadings and removal were matched and the temperature profile was approached within 5 ∘ C. An average 3.8% difference between measured and calculated values was achieved in the stripper. A three-stage flash configuration which efficiently utilizes solar energy was developed. It reduces energy use by 6% relative to a simple stripper. Intercooling was used to reach 90% removal in the absorber at these optimized conditions.

The main aim of the research is to continue the studies on promising technologies of coal conversion into synthetic liquid fuel (methanol). The object of study is the plants for combined production of electricity and synthetic liquid fuel (PCPs), which are eco-friendly and more efficient as compared to the plants for separate production. The previous studies on PCPs consider the systems for fine cleaning of gasification products in a simplified way. This study presents the detailed mathematical modeling of the aforementioned systems and determines the values of energy consumption and investment in them. The obtained values are used to carry out the optimization studies and find the optimal parameters of PCPs with different degree of CO2 removal from gasification products providing fine cleaning of gasification products from H2S.

Recent work examining likely changes in global temperatures as a result of carbon dioxide (CO 2 ) emissions has suggested that cumulative CO 2 emissions (i.e. total emissions over an extended period of time) could be more significant than the differences between particular emissions pathway (e.g. with different timing of emissions or peak emissions rate) in determining how the global climate might change in response to CO 2 emissions. This suggests that effective measures to mitigate the risk of dangerous climate change will need to limit cumulative emissions of CO 2 . Further, if cumulative CO 2 emissions overshoot acceptable limits, it will become necessary to remove CO 2 from the air–so-called ‘negative emissions’. Technologies that effect ‘negative emissions’ could also be used to offset additional anthropogenic emissions from sectors where greenhouse gas emissions are difficult or impossible to reduce beyond certain, still relatively high, limits. If the prevailing carbon price for marginal abatement options rises significantly from current levels (e.g. of order up to $200/t CO 2 has been suggested by some) then a relatively wide range of options for removing CO 2 from the air may become cost-effective. Additionally, some options for removing CO 2 from the air are likely to have much lower abatement costs. This paper summarises results from research conducted to compare and contrast various options for capturing CO 2 from the air, with a particular focus on establishing the potential of these options to have a significant impact in reducing CO 2 emissions and, if so, over what timescales.

The COCS (Cost Saving CO2 Capture System) Project had been carried out by RITE in collaboration with four Japanese companies from April 2004 to March 2009. It was the R&D project to reduce CO2 capture cost by half compared to the cost of a conventional technology for CO2 removal from a blast furnace gas in an integrated steel works. One of the main research issues in this project was to develop a novel absorbent which could be regenerated with a low thermal energy. RITE especially led the development of new absorbents. Initially amine solvents were investigated through laboratory-scale experiments, and then some selected solvents were evaluated at the 1t-CO2/d test plant. RITE successfully developed innovative amine absorbents, which have high absorption rate and low desorption energy of about 2.5–2.65 GJ/t-CO2 for CO2 capture from a blast furnace gas.

The dissolved CO 2 accumulation has become an important factor restricting production in the high-density recirculating aquaculture system in which pure oxygen injection is used. In this paper, a novel CO 2 removal device is designed for the recirculating aquaculture water environment based on the principle of gas exchange. In terms of experiments, the DOE (design of experiment) method is applied to design three factor two level orthogonal experiment, Further, significance effect of gas to liquid ratios (G / L), inlet CO 2 concentration, the water flow rate (Q W ) on CO 2 removal efficiency is analyzed. Results show that G/L has the most significant influence on the CO 2 removal efficiency. Influences of the latter two on CO 2 removal efficiency are not apparent. Tests results of G/L effect on CO 2 removal efficiency show that, when G/L=1∼5, CO 2 removal efficiency increases rapidly with the increase of G/L; when G/L=5, CO 2 removal efficiency=80%∼88%; when G/L=8, CO 2 removal efficiency=86%∼92%, when G/L>8, CO 2 removal efficiency increases gently with the increase of G/L. Considering both system energy saving and effective removal of carbon dioxide, G/L=5∼8 is considered to be the best for the aquaculture water CO2 removal device running, CO 2 removal efficiency=80%∼92%.

The cost of CO 2 removal from natural gas with subsequent storage is estimated and the results show that it can be very close to an economically viable process. The cost of removing CO 2 from a natural gas stream(sweetening) using the MDEA process is 30% lower than cost of conventional amine MEA technology for CO 2 capture from flue gas, putting this project at a much lower cost than capture from most other industrial CO 2 sources. The cost of CO 2 removal is as low as 35€/tonne. In addition natural gas sweetening projects will capture potentially larger volumes of CO 2 than many industrial projects if new large gas fields are developed. The large scale could provide the necessary amount and steady supply of CO 2 needed to kick-start the deployment of CCS. This could happen either by allowing a large-scale offshore central CO 2 storage or offshore EOR projects. Large scale storage would reduce the storage cost for CO 2 improving the cost benefit situation for a CCS project. A large scale EOR project could create a market for CO 2 in the Nordic region that also land-based industry can sell to thereby reducing their costs for CCS sufficiently to allow industrial CCS projects to start.

This paper presents a description of the CO2 removal process of 500MW coal and gas fired power plants. The parameters and other operating conditions for Aspen Plus rate based model were selected to achieve 85% of CO2 removal. The effects of absorber pressure and packing height on re-boiler duty are studied. Re-boiler duty is decreasing with the increase of packing height and absorber pressure. The effect of solvent properties on CO2 removal efficiency is also analyzed. The removal efficiency increases as the increase of MEA concentration and temperature. When the lean loading of MEA solvent is increased, efficiency of the removal process is decreasing. The liquid and vapour phase temperature profiles and CO2 loading in the absorber are analyzed to understand the model behaviour.

A CO2 capture process based on MEA absorption has been simulated with Aspen HYSYS and Aspen Plus. Both rate-based simulations and simulations with specified Murphree efficiencies have been performed. The differences between the equilibrium models and between Aspen HYSYS and Aspen Plus were small. The removal efficiency was calculated to be lower and the temperature profiles were slightly different in the rate-based calculations. The simulations were close to equivalent if the aim is to calculate CO2 removal efficiency as a function of circulation rate, number of column stages and inlet temperature.

The fire developed in an MDEA CO2 removal system because of switching from one semi-lean pump to another.

The development of redox CO2 carrier molecules capable of binding CO2 and releasing it will provide a basis for efficient CO2 removal system for possible applications on long-duration manned space missions. The objective of research being conducted is the utilization of these carriers to develop membranes to selectively and efficiently pump CO2 when a potential is applied across the membranes. The topics covered include the effects of pumping rate and CO2 solubility on carrier efficiency, chemical requirements of redox active carriers, and the screening and evaluation of potential carriers.

Low frequency jet ventilation was used successfully for maintaining normal ventilation during tracheal resection for stenosis. Following resection of the stenosis around the endotracheal tube, the tube was withdrawn and the proximal end of a sterile double lumen nasogastric tube with the distal end removed passed over the ether screen. The larger lumen was connected to a Saunders jet apparatus and the smaller to a CO2 analyzer. With the distal end held in the lumen of the distal tracheal stump, jet ventilation was initiated at a rate of 20/min at a pressure sufficient to obtain adequate chest rise and fall. Adequate CO2 removal was verified by monitoring the expired level and blood gases. We obtained normal arterial and end tidal gas tensions by this method which allowed the surgeon complete freedom to anastomose the posterior and lateral tracheal walls.

Tracheal and alveolar gas composition was studied by mass spectrometry in a patient with severe ARDS treated by low frequency positive pressure ventilation/extracorporeal CO2-removal (LFPPV-ECCO2R). Measured alveolar gas concentrations were compared with values derived from standard respiratory equations. As a result we found that during LFPPV-ECCO2R with a constant endotracheal O2-flow, alveolar gas composition cannot be predicted reliably from standard equations. The reasons for this finding are discussed. We conclude that monitoring of alveolar gas composition by mass spectrometry is of great value during LFPPV-ECCO2R if PAO2, P(A-a)O2 and Qva/Qt are to be determined correctly.

NASA's Langley and Goddard facilities have evaluated the effects of animal science experiments on the Space Station's Environmental Control and Life Support System (ECLSS) by means of computer-aided analysis, assuming an animal colony consisting of 96 rodents and eight squirrel monkeys. Thirteen ECLSS options were established for the reclamation of metabolic oxygen and waste water. Minimum cost and weight impacts on the ECLSS are found to accrue to the system's operation in off-nominal mode, using electrochemical CO2 removal and a static feed electrolyzer for O2 generation.

An advanced flight prototype regenerable CO2 and humidity control system was delivered to NASA-JSC in February 1980. It is pointed out that this system offers substantial weight savings compared with the Shuttle Orbiter expendable lithium hydroxide CO2 removal system for extended duration missions. The present paper provides a brief description of the 4- to 10-man regenerable CO2 and humidity control system. The potential advantages which can be realized for an extended duration Shuttle mission are considered along with the results of extensive testing conducted at JSC. The performance evaluation and endurance tests show that the system is capable of long-term operation (up to 60 days) without maintenance.

A low molecular weight heparin (LMWH, Sandoz), a standard heparin (SH, LiqueminR) and ancrod (Arvin^)have been compared in an extracorporeal veno-venous bypass for CO2 removal using a membrane lung in dogs. Four animals received 150 anti-FXa U/kg in bolus followed 90 min later by 40 anti-FXa U/kg/h of LMWH and four other 300 IU/kg followed by 100 IU/kg/h of SH. Six dogs received 1 U/Kg of ancrod intravenously during 2 h before bypass started.Mean FXa inhibition was 49% in LMWH group and 29% in SH group, mean FI la inhibition 31% and 49% respectively. No statistically significant differences were found between LMWH and SH groups for any of the parameters measured (fibrinogen, FV, antithrombin III, plasminogen, α 2-anti piasmin, platelet counts). At the end of bypass 5000 U protamine abolished both anti-FXa and anti-FIIa activities in SH group, but failed to neutralize more than half of anti-FXa in LMWH group. In ancrod group no clottable fibrinogen was detectable. A dramatic fall of α2-antiplasmin was observed after ancrod infusion and, during bypass, sharp decreases in FV and platelet counts without significant antithrombin III and plasminogen consumption were noted.No bleeding occurred in any group throughout the seven hours of bypass. The main finding was fibrin deposition in the tubing in three out of four dogs receiving LMWH, whereas no fibrin deposition occurred either in SH or in ancrod group.These results suggest that in this model which involves blood contact with artificial surfaces (1) SH and ancrod are efficient to prevent clotting, but not the LMWH used at the dosage reported (2) high anti-FIIa activities are required to prevent fibrin formation (3) ancrod defibrination does not protect against severe haemostatic disturbances and (4) the use of LMWH may raise problems when emergency neutralisation procedures are required.

The development of a CO2 removal system for an astronaut portable life support system to meet the EVA requirements for the Space Station is discussed, focusing on the factors important in the selection of the metal oxide absorbent for CO2 removal. Results from laboratory tests on metal oxide absorbent materials are given, including characterization studies and dynamic CO2 uptake and regeneration measurements. The preliminary design of the breadboard system to perform both the absorption and regeneration functions is presented.

A recently developed hollow fiber membrane oxygenator, made of microporous polypropylene (Capiox, Terumo, 1.6 m2) was tested to evaluate the hemocompatibility and the ease and safety of operation. Two types of this oxygenator were tested: one with and one without an integral heat exchanger. Each type was tested in 6 dogs during a partial bypass of 2 hours at a flow rate of 2 l/min. In addition, gas transfer measurements were carried out. The Terumo oxygenator preserved the blood cells and the platelet function very well. In addition, neither the Wu-Hoak index, a method to measure platelet aggregates, nor inspection of the oxygenator revealed platelet aggregates. Operation and debubbling procedure were easy and safe. The estimated rated blood flow for O2 was 1.5 l/min with a corresponding CO2 removal of 90 ml/min. The integral heat exchanger did not affect the results significantly. Our data show that this oxygenator is easy and safe to use. Clinical evaluation is recommended.

This paper presents a status review of Spacecraft Air Revitalization System (ARS) integration using regenerable techniques. The paper addresses concepts of integration of individual subsystems into an Air Revitalization System, as well as integration of components within subsystems. An ARS design is presented based on the Electrochemical Depolarized Carbon Dioxide Concentrator Subsystem, the Sabatier Carbon Dioxide Reduction Subsystem, the Static Feed Water Electrolysis Subsystem, a condensing Humidity Control Subsystem, and a Water Handling Subsystem to perform the functions of CO2 removal, CO2 reduction, O2 generation, humidity control and by-product water distribution, respectively. The paper also highlights the numerous advantages of this integration. Trace contaminant control and the nitrogen supply are not included in the ARS described in this paper.

HIGEE is a rotation mass transfer apparatus in which centrifugal force is used to intensify mass transfer. This paper deseribes a joint

Biogas serves a reliable renewable resource and energy carrier with growing potentials based on the number and size of plants in operation and planned for future. The technical viability of membranes for biogas valorization has attracted attention towards further advancements from the materials and process perspectives. The present review aims to meticulously analyze the extensive works carried out at laboratory, pilot, semi-industrial and industrial scales pertinent to biogas with the aid of membrane separation processes. Discussions are devoted to the performance characteristics and specifications of various membrane materials, processes and configurations employed spanning the entire value chain of biogas production, upgrading and conversion. These include recovery of dissolved methane and liquids (water, ammonia) at the production stage, as well as exploitation of semipermeable and gas-liquid membranes such as membrane contactors, membrane reactors and membrane bioreactors for upgrading of raw biogas to achieve quality biomethane. Besides, valuable experiences in integration of membranes in hybrid configurations for biogas upgrading are evaluated. Also, the emerging trends in biogas conversion are delineated by focusing on methanation and hydrogenation with the aid of membranes. Finally, guidelines for the design, integration and optimization of high-performance membrane systems are set by taking into account the economic considerations.

Poster presented in AlgaEurope 2018 Conference. Influence of different operating parameters on biomethane quality during biogas upgrading coupled to wastewater treatment in algal-bacterial photobioreactors.

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy is a rescue strategy for severe cardiopulmonary failure. The estimation of cardiac output during VA-ECMO is challenging. A lung circuit ($${\dot{\text{Q}}}$$ Q ˙ Lung) and an ECMO circuit ($${\dot{\text{Q}}}$$ Q ˙ ECMO) with oxygenators for CO2 removal ($$\mathop {\text{V}}\limits^{.}$$ V . CO2) and O2 uptake ($$\mathop {\text{V}}\limits^{.}$$ V . O2) simulated the setting of VA-ECMO with varying ventilation/perfusion ($$\mathop {\text{V}}\limits^{.}$$ V . /$${\dot{\text{Q}}}$$ Q ˙ ) ratios and shunt. A metabolic chamber with a CO2/N2 blend simulated $$\mathop {\text{V}}\limits^{.}$$ V . CO2 and $$\mathop {\text{V}}\limits^{.}$$ V . O2. $${\dot{\text{Q}}}$$ Q ˙ Lung was estimated with a modified Fick principle: $${\dot{\text{Q}}}$$ Q ˙ Lung = $${\dot{\text{Q}}}$$ Q ˙ ECMO × ($$\mathop {\text{V}}\limits^{.}$$ V . CO2 or $$\mathop {\text{V}}\limits^{.}$$ V . O2Lung)/($$\mathop {\text{V}}\limits^{.}$$ V . CO2 or $$\mathop {\text{V}}\limits^{.}$$ V . O2ECMO). A normalization procedure corrected $$\mathop {\text{V}}\limits^{.}$$ V . CO2 values for a $$\mathop {\text{V}}\limits^{.}$$ V . /$${\dot{\text{Q}}}$$ Q ˙ of 1. Method agreement was evaluated by Bland–Altman analysis. Calculated $${\dot{\text{Q}}}$$ Q ˙ Lung using gaseous $$\mathop {\text{V}}\limits^{.}$$ V . CO2 and $$\mathop {\text{V}}\limits^{.}$$ V . O2 correlated well with measured $${\dot{\text{Q}}}$$ Q ˙ Lung with a bias of 103 ml/min [− 268 to 185] ml/min; Limits of Agreement: − 306 ml/min [− 241 to − 877 ml/min] to 512 ml/min [447 to 610 ml/min], r2 0.85 [0.79–0.88]). Blood measurements of $$\mathop {\text{V}}\limits^{.}$$ V . CO2 showed an increased bias (− 260 ml/min [− 1503 to 982] ml/min), clinically not applicable. Shunt and $$\mathop {\text{V}}\limits^{.}$$ V . /$${\dot{\text{Q}}}$$ Q ˙ mismatch decreased the agreement of methods significantly. This in-vitro simulation shows that $$\mathop {\text{V}}\limits^{.}$$ V . CO2 and $$\mathop {\text{V}}\limits^{.}$$ V . O2 in steady-state conditions allow for clinically applicable calculations of $${\dot{\text{Q}}}$$ Q ˙ Lung during VA-ECMO therapy.

To investigate the role of complement activation in the adult respiratory distress syndrome (ARDS) and in the complications of extracorporeal circulation (ECC), several parameters (CH50, C3 split products, C3a, C5a, PMN aggregating activity, carboxypeptidase activity) of the complement profiles of 23 ARDS patients were measured. Twenty patients were treated by long-term extracorporeal support. Before connection to ECC, marked leukocytosis (18,250 ± 5,950) and significantly high plasma C3a levels (p < 0.005) were observed. After connection, C3a levels increased further, up to values eight times higher than the basal ones. The WBC count transiently decreased to 41% of prebypass levels after 15 minutes of ECC. At the same time C3 split products appeared and PMN aggregating activity was shown in 52% of the patients. C5a levels remained normal during bypass, even in two samples in which PMN aggregating activity was detected. Later decreases in CH50 titers (p < 0.001) and carboxypeptidase activity (p < 0.005) were observed. Complement activation was no longer evident after the 24th hour of bypass. We conclude that there is a low-degree complement activation in ARDS, and ECC is a further strong stimulus for complement activation. This phenomenon appears, however, to be self-limited.

High-flow nasal cannula (HFNC) is increasingly proposed as respiratory support for hypoxemic non-intubated acute respiratory failure patients. Clinically, HFNC therapy decreases dyspnea, improves patient's comfort, improves oxygenation and enhances clearance of upper airway secretions [1]. We present preliminary results from a clinical study aimed at measuring the effects of HFNC on gas exchange, lung volumes and inspiratory effort in hypoxemic non-intubated critically ill patients.

Ventilation of ARDS patients with low tidal volume (Vt) is performed in order to minimize ventilation induced lung injury. This strategy, however, may induce hypercapnic acidosis, promote derecruitment and, in some individuals, induce alveolar overdistention despite the use of low Vt. Extracorporeal CO2 removal can help minimizing hypercapnic acidosis and to further reduce Vt (i.e. ultraprotective ventilation).

Pump-driven venovenous extracorporeal CO2 removal (ECCO2-R) increasingly takes root in hypercapnic lung failure to minimize ventilation invasiveness or to avoid intubation. A recently developed miniaturized device consisting of a centrifugal pump and a membrane ventilator (iLA Activve®; Novalung, Germany) allows effective decarboxylation via a jugular double lumen cannula. So far no data on gas exchange in this setting exist to date.