A Hybrid Pyrolysis / Oxidation System for Solid Waste Resource Recovery

Wheat, maize and cotton, grown as spaced plants in large pots of soil, differed in the way high (2 X ambient) CO2 concentration affected the time-course of soil water use. For wheat, the tendency to conserve water owing to reduction in stomatal conductance in high CO2 was largely offset by the stimulation of leaf area development as the soil column dried. However, when the soil was maintained continuously wet, soil water conservation occurred because in the absence of water stress high CO2 did not maintain a greater leaf area. For maize, which has little or no photosynthetic response to CO2 concentrations above ambient but a strong stomatal response, water was conserved and the soil profile dried more slowly. Maize leaf area and dry matter growth increased in response to damper soil under high CO2, despite no growth response to CO2 in the absence of water stress. For cotton, which has a strong photosynthetic but weak stomatal response to CO2, the soil column dried faster under high CO2. Despite this drier soil, cotton still showed the greatest response to high CO2 of leaf area and dry matter growth of the three species compared. Under wet soil conditions, cotton exhibited a very large leaf area response to CO2 leading to much greater water use per plant. This contrasts with both wheat and maize which con- served water at high CO2 when wet. Despite these contrasting transpiration and growth responses, all three species exhibited a relatively similar increase in water use efficiency under high CO2 for both wet and dry conditions. It is concluded that the secondary effect of high CO2 on soil water content exerts a strong confounding influence on growth responses to CO2. In the longer term, the changed soil water status would influence hydrology, soil microbiology, nutrient relations and species composition. From indirect evidence it is proposed that the relative enhancement of growth owing to CO2 enrichment is greater under drought conditions than in wet soil because of the effect of water deficit on the intercel-

<div class="htmlview paragraph">The 1975 federal CVS test procedure and emission standards have placed a heavy emphasis on minimizing the time required after engine start up to begin converting exhaust emissions. Four major improvements in catalytic HC/CO converters have been made in the past year to reduce catalyst ignition time:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">Use of low thermal capacity monolithic catalyst supports.</div> </li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">Locating converter after thermal reactor and/or closer to the exhaust manifold.</div> </li> <li class="list-item"> <span class="li-label">3.</span> <div class="htmlview paragraph">Development of catalysts with superior stability to long exposure at high temperatures.</div> </li> <li class="list-item"> <span class="li-label">4.</span> <div class="htmlview paragraph">Development of catalysts with improved low temperature activity.</div> </li> </ol> </div> <div class="htmlview paragraph">Small laboratory samples of potential HC/CO oxidation catalysts were screened for activity in a “laboratory simulated cold-start” test with exhaust from a 2-cyl engine. Several improved catalyst candidates were evaluated in a full-size converter “cold-start” test with exhaust from a 351 in<sup>3</sup> engine.</div> <div class="htmlview paragraph">Locating the converters closer to the exhaust manifold results in higher catalyst operating temperatures which require greater stability at high temperatures in the presence of trace contaminants. Stability, when exposed to wide temperature variations and changes from oxidation to reduction environments, has been evaluated in a thermal-cycling test for several improved catalysts. Catalyst stability to long-term exposure has also been evaluated in an engine dynamometer mileage accumulation test operated under simulated road conditions.</div> <div class="htmlview paragraph">Unfortunately, the rapid thermal-chemical response of the improved catalyst, operated closer to the exhaust manifold, increases the occurrences of excessive catalyst temperatures. Mathematical model studies of the effect of the improved catalyst properties on thermal response indicate a need to prevent unexpected high CO or HC concentration peaks in the engine exhaust, or to improve properties of existing catalysts. System changes, such as moving the low temperature catalyst farther from the exhaust manifold, may be required to obtain some protection from catalyst overtemperatures. These changes increase emission levels and require a breakthrough in engine control of raw emissions or improved catalysts.</div>

<div class="htmlview paragraph">Controlled Auto-Ignition (CAI) combustion, also known as HCCI or PCCI, has recently emerged as a viable alternative combustion process to the conventional spark ignition (SI) or compression ignition (CI) process for internal combustion (IC) engines, owing to its potential for high efficiency and extremely low emissions. One of the most effective and practical means of achieving CAI combustion in an engine is to retain or recycle the burnt gases. In order to understand better the effects of recycled burnt gases on CAI combustion, detailed analytical and experimental studies have been carried out. The analytical studies were performed using an engine simulation model with detailed chemical kinetics.</div> <div class="htmlview paragraph">The five effects of the recycled burned gases studied include:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">Charge heating effect: higher intake charge temperature due to hot burned gases;</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">Dilution effect: the reduction of oxygen due to the presence of the burned gases;</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">Heat capacity effect: due to higher specific heat capacity of burned gases;</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">Chemical effect: chemical reactions involving CO<sub>2</sub> and H<sub>2</sub>O in the burned gases</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">Stratification effect: recycled burned gases are stratified from the fuel/air mixture.</div></li> </ol> </div> <div class="htmlview paragraph">And the main conclusions are:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">The charge heating effect is mainly responsible for the advanced AI timing due to hot burned gases. It increases the heat release rate and shortens the combustion duration.</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">The dilution effect does not affect AI timing, but it extends combustion duration. Its slows down the heat release rate only when large amount of burned gases is present.</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">The heat capacity effect is mainly responsible for the reduction in the heat release rate, and it has a similar effect to extend the combustion duration as the dilution effect.</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">The chemical effect does not affect AI timing and heat release rate. It reduces the combustion duration slightly at high concentrations of burned gases.</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">The stratified burned gases facilitate the CAI combustion due to the presence of higher temperature region at the boundary between of the hot burned gases and combustible charge.</div></li> </ol> </div>

The catalytic CO oxidation over polycrystalline LaMnO3 exhibits a bistability at high CO concentration. Under atmospheric pressure, the regime of bistability extends from 200 to 220°C and widens with increasing CO concentration. A systematic study of the solid solution system La1‐xSrxMnO3 which crystallizes in the perovskite structure, shows that the width of the bistable regime decreases with an increasing amount of strontium substitution and no bifurcation was observed for x > 0.2. A model is proposed to explain the bistability, based on a CO‐driven reconstruction of the reduced surface, leading to pairs of Mn2 ions with a Mn‐Mn distance comparable to the spacing in the metal. These pairs provide reactive sites for CO oxidation and oxygen chemisorption. Such metal‐metal pairs are not found in the perovskite lattice but are a structural feature of the closely related hexagonal 4‐layered packing which is the normal crystal structure of SrMnO3. The rate of change back to the “oxidized” surface is found to correlate with the lattice oxygen mobility. With low oxygen mobility, the transition from the active into the less active state becomes slow and hysteresis may result. Strontium substitution increases the number of defects in the oxygen lattice and leads ultimately to an oxygen deficiency (reductive nonstoichiometry). The catalytic activity of the system peaks at x = 0.2, indicating the influence of both the oxygen mobility and the oxygen nonstoichiometry on the catalytic oxidation reaction.

Lycopersicon esculentum Mill. cv Vedettos and Lycopersicon chmielewskii Rick, LA 1028, were exposed to two CO(2) concentrations (330 or 900 microliters per liter) for 10 weeks. The elevated CO(2) concentrations increased the initial ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity of both species for the first 5 weeks of treatment but the difference did not persist during the last 5 weeks. The activity of Mg(2+)-CO(2)-activated Rubisco was higher in 900 microliters per liter for the first 2 weeks but declined sharply thereafter. After 10 weeks, leaves grown at 330 microliters per liter CO(2) had about twice the Rubisco activity compared with those grown at 900 microliters per liter CO(2). The two species showed the same trend to Rubisco declines under high CO(2) concentrations. The percent activation of Rubisco was always higher under high CO(2). The phosphoenolpyruvate carboxylase (PEPCase) activity measured in tomato leaves averaged 7.9% of the total Rubisco. PEPCase showed a similar trend with time as the initial Rubisco but with no significant difference between nonenriched and CO(2)-enriched plants. Long-term exposure of tomato plants to high CO(2) was previously shown to induce a decline of photosynthetic efficiency. Based on the current study and on previous results, we propose that the decline of activated Rubisco is the main cause of the acclimation of tomato plants to high CO(2) concentrations.

Biomethanation of syngas at high CO concentration in a continuous mode

SummaryWe evaluated the usefulness of end‐tidal CO (ETCO) as an internal standard for reducing the error in end‐tidal H2 (ETH2) measurements due to contamination of repeated breath samples with nonalveolar gas. Triplicate end‐tidal samples were drawn from 12 healthy premature infants in small (< 1 cc) increments through a posterior nasopharyngeal catheter at end‐expiration, determined from the infant's chest wall movement. CO and H2 determinations were made on each sample by a reduction gas detector capable of determining CO and H2 concentrations to ±0.001 and 0.010 ppm, respectively. Respiratory breath samples were corrected for ambient CO and H2 concentrations. Since the alveolar gas fraction has the highest CO concentration of all tidal gases, the end‐tidal sample with the highest CO peak was assumed to be most representative of uncontaminated alveolar gas. The other samples were “corrected” using a factor that was the ratio of the patient's highest CO peak to the given sample's CO value. The use of ETCO to correct ETH2 from samples deliberately contaminated with ambient air can significantly reduce the variability of ETH, values. However, such correction is probably not necessary when comparing groups of infants using a standard collection technique. For individual infants, correction may reveal more marked short‐term fluctuations in true alveolar H2 concentration.

The recent eruption of Tajogaite volcano occurred between September and December 2021 at La Palma Island is considered the most devastating of Europe since that of Vesuvio in 1944. The post-eruptive period is being characterized by the appearance of high outdoor and indoor CO2 concentrations at inhabited areas such as La Bombilla and Puerto Naos (Hernández et al., 2022), forcing the eviction of numerous homes. However, anomalous concentrations of CO2 have not only appeared in inhabited areas, but also in cultivated lands. In fact, the highest CO2 concentration values measured in the outdoor environment during the entire post-eruption period have been in a banana plantation of approximately 4,200 m2 that INVOLCAN has been monitoring since June 2022, named Las Hoyas.Since June 2022, 26 scientific observation surveys have been carried out at Las Hoyas consisting of the measurement at 39 homogeneously distributed sites of the CO2 and O2 concentration at two heights, 40 and 170 cm from the ground, as well as sampling of atmospheric air in 19 sites at 40 cm for carbon isotope ratio of air CO2. Air CO2 and O2 concentrations are measured with a hand portable Dräger X-am® 8000 meter and the carbon isotope ratio of air CO2 (expressed as δ13C-CO2 ‰ vs. VPDB) is analyzed at ITER/INVOLCAN lab by a Thermo Finnigan MAT 253 mass spectrometer. Spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) to evaluate the spatial distribution of the air CO2 concentration. Observed air CO2 concentration values ranged from air value (412ppm) up to 69%, the highest ever measured during the post-eruptive period, with an average value of 7.1%. Air O2 concentration values ranged between 7.9% to air value (20.9%), with an average value of 19.2%. δ13C-CO2 values ranged between –8.90 to -2.66‰, with an average value of -4.87‰, indicating a clear volcanic-hydrothermal origin for the anomalous CO2 emitted from Las Hoyas banana plantation and ruling out a single biogenic origin.In order to investigate the temporal evolution of the observed high CO2 concentrations in Las Hoyas, a Sinclair statistical graphic analysis was applied to the data from each survey. Time series of background and peak populations does not show a clear trend, with the occurrence of peaks and valleys throughout the entire series, and maintaining values much higher than those of the air. Likewise, the temporal evolution of the δ13C-CO2 values shows a trend towards heavier values, indicating that the volcanic-hydrothermal contribution increases with time. The spatial distribution of the air CO2 concentration measured at 40 cm shows that in most of the surveys, the anomalous values (>10%) are located mainly along the walls of Las Hoyas and in the NW sector, where in more than a year after the eruption, the banana plants are still withered and dead terrestrial and aerial fauna constantly appear due to poisoning and suffocation from CO2 inhalation. Hernández et al. EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7705, https://doi.org/10.5194/egusphere-egu22-7705, 2022.

Several studies related to CH4 cycling focus on the effect of elevated atmospheric CO2 levels on soil methanogenesis and methanotrophy. However, periodically waterlogged soils are characterized by much higher CO2 concentrations, while aggregates forming in arable soils due to traditional cultivation may be a natural CH4 source for low-affinity methanotrophs. We present a comprehensive laboratory investigation into both methanogenesis and methanotrophy in three different soils under ambient and high CO2 concentrations. The tested materials were agricultural soils widely distributed in Europe: Eutric Cambisol, Haplic Podzol and Mollic Gleysol with determined properties: Corg, Ntot, clay, silt, sand, pH, NO3−, NH4+. We conducted two independent experiments on methanogenesis (flooded conditions) and methanotrophy (non-flooded conditions). All samples for both studies were divided into three sets which differed in the initial CO2 concentration in headspace: ambient CO2 (0.03% v/v ± 0.005), and two high CO2 levels (5% ± 0.4 and 10% ± 0.5 v/v CO2). Moreover, 1% (v/v) of CH4 was added to all sets prepared for the methanotrophy test since low-affinity methanotrophy in the tested soils had been reported previously. Gas concentrations (CH4, CO2, O2) in headspace were measured using gas chromatography method. We observed that the examined soils differed in their ability to produce CH4 as follows: Haplic Podzol = Eutric Cambisol > Mollic Gleysol, as well as to consume CH4: Mollic Gleysol > Haplic Podzol > Eutric Cambisol. The CH4 emissions started faster in Gleysol, but the final CH4 concentration and CH4 production rate in this soil were significantly lower than in the two other soils. The CH4 uptake rate significantly differed among the tested soils. The MANOVA confirmed the significance of the soil-type factor in determining both process rates, whereas the effect of CO2 level and the interaction between both factors were not significant. The amount of consumed O2 during CH4 oxidation was also characteristic for examined soil, but did not differ significantly between CO2 variants. CH4 production and consumption in three different soils (Eutric Cambisol, Haplic Podzol and Mollic Gleysol) collected from periodically waterlogged arable fields were more strongly affected by soil properties than by high CO2 concentration. In contrast, the high CO2 level significantly decreased CO2 production accompanying tested the CH4-related processes.

BackgroundMicroalgae are diverse in terms of their speciation and function. More than 35,000 algal strains have been described, and thousands of algal cultures are maintained in different culture collection centers. The ability of CO2 uptake by microalgae varies dramatically among algal species. It becomes challenging to select suitable algal candidates that can proliferate under high CO2 concentration from a large collection of algal cultures.ResultsHere, we described a high throughput screening method to rapidly identify high CO2 affinity microalgae. The system integrates a CO2 mixer, GasPak bags and microplates. Microalgae on the microplates will be cultivated in GasPak bags charged with different CO2 concentrations. Using this method, we identified 17 algal strains whose growth rates were not influenced when the concentration of CO2 was increased from 2 to 20% (v/v). Most CO2 tolerant strains identified in this study were closely related to the species Scenedesmus and Chlorococcum. One of Scenedesmus strains (E7A) has been successfully tested in in the scale up photo bioreactors (500 L) bubbled with flue gas which contains 10-12% CO2.ConclusionOur high throughput CO2 testing system provides a rapid and reliable way for identifying microalgal candidate strains that can grow under high CO2 condition from a large pool of culture collection species. This high throughput system can also be modified for selecting algal strains that can tolerate other gases, such as NOx, SOx, or flue gas.

<div class="htmlview paragraph">Viability of bioregeneration for life support – providing food, water and air – on long-duration missions depends critically on cost of the plant habitat and on plant productivity in this habitat. Previous estimates, e.g. <span class="xref">Drysdale and Wheeler, 2002</span> of both cost and productivity have been made using existing chamber designs, in particular the BIO-Plex (Bioregenerative Planetary Life Support Systems Test Complex) Plant Growth System intermediate design review (IDR) design. However, this design was developed for a terrestrial testbed, and is not optimized for use in space, much less for a particular space environment. Nor has productivity been determined experimentally for this configuration.</div> <div class="htmlview paragraph">We have examined this design and updated it for use on the Moon, with 709-hr days (light / dark cycles), using both natural and artificial light. Each system within the plant habitat was evaluated and modified to some extent for the desired use. Plant productivity was estimated for the expected conditions. Cost impact was calculated using equivalent system mass (ESM). Major improvements are likely by using natural sunlight during the Lunar day and a reduced level of artificial light during the Lunar night.</div>

Elodea canadensis grows over a wide range of inorganic carbon, nutrient, and light conditions in lakes and streams. Affinity for HCO 3- use during photosynthesis ranged from strong to weak in Elodea collected from seven localities with different HCO 3- and CO2 concentrations. The response to HCO 3- was also very plastic in plants grown in the laboratory at high HCO 3- concentrations and CO2 concentrations varying from 14.8 to 2,200 μM. Bicarbonate affinity was markedly reduced with increasing CO2 concentrations in the growth medium so that ultimately HCO 3- use was not detectable. High CO2 concentrations also decreased CO2 affinity and induced high CO2 compensation points (360μM CO2) and tenfold higher half-saturation values (∼800 μM CO2).The variable HCO 3- affinity is probably environmentally based. Elodea is a recently introduced species in Denmark, where it reproduces only vegetatively, leaving little opportunity for genetic variation. More important, local populations in the same water system had different HCO 3- affinities, and a similar variation was created by exposing one plant collection to different laboratory conditions.Bicarbonate use enabled Elodea to photosynthesize rapidly in waters of high alkalinity and enhanced the carbon-extracting capacity by maintaining photosynthesis above pH 10. On the other hand, use of HCO 3- represents an investment in transport apparatus and energy which is probably not profitable when CO2 is high and HCO 3- is low. This explanation is supported by the findings that HCO 3- affinity was low in field populations where HCO 3- was low (0.5 and 0.9 m M) or CO2 was locally high, and that HCO 3- affinity was suppressed in the laboratory by high CO2 concentrations.

Soybean (Glycine max L. Merrill cv ;Bragg') plants were grown in pots at six elevated atmospheric CO(2) concentrations and two watering regimes in open top field chambers to characterize leaf xylem potential, stomatal resistance and conductance, transpiration, and carbohydrate contents of the leaves in response to CO(2) enrichment and water stress conditions. Groups of plants at each CO(2) concentration were subjected to water stress by withholding irrigation for 4 days during the pod-filling stage.Under well watered conditions, the stomatal conductance of the plants decreased with increasing CO(2) concentration. Therefore, although leaf area per plant was greater in the high CO(2) treatments, the rate of water loss per plant decreased with CO(2) enrichment. After 4 days without irrigation, plants in lower CO(2) treatments showed greater leaf tissue damage, lower leaf water potential, and higher stomatal resistance than high CO(2) plants. Stomatal closure occurred at lower leaf water potentials for the low CO(2) grown plants than the high CO(2) grown plants. Significantly greater starch concentrations were found in leaves of high CO(2) plants, and the reductions in leaf starch and increases in soluble sugars due to water stress were greater for low CO(2) plants. The results showed that even though greater growth was observed at high atmospheric CO(2) concentrations, lower rates of water use delayed and, thereby, prevented the onset of severe water stress under conditions of low moisture availability.

High CO(2) concentration (0.5%) increased the rate of ethylene production, measured in a continuous flow system, in intact sunflower (Helianthus annuus L.) plants. However, the rate of ethylene production subsided to near control levels after approximately 24 hours. The effect of high CO(2) could only be observed in light. Although high CO(2) concentration had no effect on the rate of ethylene production in darkness, prolonged exposure (approximately 16 hours) of plants to high CO(2) in the dark prevented the increase in ethylene production when the plants were exposed to light and high CO(2).

The amount of condensed water should be carefully estimated in gas development plans, especially for fields with high CO2 content. This may affect the design of the well, surface facilities such as water treatment equipment and CO2 removal units, and flow assurance and corrosion control strategies. However, reliable prediction of the water content of gas with high CO2 level in contact with formation brine is still a challenge. The actual condensed water production data from a sour gas field offshore peninsular Malaysia has indicated that the condensed water levels are higher than estimated in the field development plan (FDP). The trend of water/gas ratios (WGR) across the field was analyzed versus depth, pressure, temperature and CO2 content of the reservoirs. To isolate the primary source of errors in the measured WGR from production tests, the measured water/condensate splits were verified with liquid/gas ratio (LGR) using calculated CGRs based on equation-of-state models. Salinity measurements of lower than 300 ppm were considered as fresh water. Equilibrium-based predictive tools were used to estimate the condensed water levels according to gas composition, pressure, temperature and water salinity. The results demonstrate significant differences between the EOS model prediction and the actual condensed water production. This might be due to the CO2 content of different reservoirs, in-situ pressure-temperature conditions, formation water salinity, the water vaporization around the wellbore due to the high gas velocity, the dry-out effect, or may be attributed to non-equilibrium concepts. This paper details the investigation of high condensed water production in the field and what cautions that must be taken into account in developing such fields. A new correlation was developed to predict the amount and trend of condensed water in the field with various CO2 levels. The study results can be used as a useful reference during the development planning of similar fields. Introduction The amount of water production from the gas fields prior to water breakthrough can be affected by both thermodynamic and kinetic bahaviour of the fluid flow in the reservoir and more particularly in the near wellbore area. Parameters, which affect the thermodynamic conditions and determine the water content of the gas, are temperature, pressure, formation water salinity, gas composition and CO2 content. Near wellbore area kinetic and non-equilibrium facts such as gas velocity, drawdown, gas stripping, water vaporization and dry out phenomena may also affect the amount of the produced water. All of these parameters must be considered to quantify the produced water prior the water breakrough time. During full field review of a particular sour gas field on the edge of the Malay Basin, it is observed that at the initial stage of reservoir life, many of the field's reservoirs were produced with constant higher water levels than the estimated condensed water based on the equilibrium conditions. Investigation has been undertaken to explain the source and amount of high water production in the field. The high condensed water levels should be considered carefully in the development plans for high CO2 levels gas fields in the region as they may impact the design of surface facilities, such as water treatment equipment, CO2 removal units and corrosion protection for pipelines.