Hospital Oxygen Supply Overwhelmed Due to COVID-19: When Demand Exceeds Supply.

BACKGROUND: During the first wave of COVID-19, we experienced problems with our hospital oxygen supply system. This study aimed to analyze factors that stressed this system and rethink the design criteria of the gas pipeline system considering the varying oxygen demand. METHODS: A retrospective study was conducted to describe problems that occurred at different stages in the oxygen supply system at our hospital due to increases in oxygen use in general, and the creation of an intermediate respiratory care unit (IRCU) and use of high-flow nasal cannula (HFNC) in particular. Herein, the characteristics and design criteria of the medical gas pipeline system are analyzed, and the steps taken to avoid future problems are outlined. RESULTS: Increases in oxygen use were observed at times of maximum occupancy, and these created vulnerabilities in the oxygen supply due to insufficient capacity in terms of cryogenic tanks, evaporators, and the piping network. The peak consumption was 3 times higher than the peak in the preceding 4 years. The use of HFNC therapy aggravated the problem; IRCU use accounting for as much as two-fifths of the total across the hospital. Steps taken subsequently prevented the recurrence of vulnerabilities. CONCLUSIONS: The design criteria for storage and distribution networks of medical gases in hospitals need to be revised considering new parameters for their implementation and the use of HFNC therapy in an IRCU. In particular, the cryogenic tanks, evaporators, and piping network for hospital wards are critical.

Investigation on thermochemical co-gasification of rice husk and groundnut shell in open core gasifier for the generation of producer gas: An optimization by central composite design.

Several energy-related strategies and scenarios have been suggested to address concerns about rising global temperatures. In addition to using renewable energy, the improvement in energy efficiency of conventional systems is also in focus. Policies are already in place in many countries, including India, to address the energy needs of rural and small-scale enterprises by gasifying locally available, diverse agricultural leftovers. Although rice husk and groundnut shell are two commonly used agricultural leftovers in the southern part of India, their appropriate blending must be studied to improve their conversion efficiency in co-gasification. Therefore, the primary objective of this research is to construct a statistical model utilizing response surface methodology (RSM) to analyze the thermochemical co-gasification of the aforementioned biomass materials. Since RSM can predict optimum performance with limited experimental data, this could contribute to the identification of the performance and operating parameters of an open-core gasifier. The model predicts that the mixture containing 20% rice husk and working at an ER of 0.25 and a reduction zone inlet temperature of 879.9 °C will be CO-23.53%, H2-13.97%, and CH4-3.56%. In addition, the lower heating value and gas yield can be as high as 6.17 MJ/Nm3 and 2.369 m3/kg, respectively. This outcome can contribute to the effective utilization of biomass for energy supply in rural areas. However, the economic parameters must be analyzed to implement the same in any region.

Gasification of MDF residue in an updraft fixed bed gasifier to produce heat and power via an ORC turbine.

Biomass, which is a renewable resource, is regarded as an essential energy source due to its accessibility and abundance. In this study, the gasification of wood-based biomass wastes from the medium density fiberboard (MDF) facility was carried out and investigated utilizing an updraft fixed bed gasifier. The feeding capacity of the upstream gasifier is 2100 kg/h. MDF wastes are loaded into the system with feeding capacities of 1500, 1750 and 2100 kg/h. As a reference, the system has also been tested with oak wood chips at a maximum rate of 2100 kg/h. Produced syngas production rate to biomass waste is approximately 2.5 Nm3/kg. The measured gas compositions are CO, CO2, CH4, H2, O2 and N2. Test results with 2100 kg/hMDF wastes have similar gas composition compared to the test results with oak wood chips. The quality of the syngas produced by gasification is directly related to the fuel. It has been observed that the efficiency of the gasification process can be directly or indirectly impacted by the properties of the fuel, such as the moisture content, chemical compositions, and size. The temperature of the produced gas is approximately 430 °C, and it isdirectly combusted with tars and soot it contains to ensure that no chemical energy is lost. The thermal gasification system converts approximately 88% by weight of MDF residue to syngas. The calorific value of produced syngas is obtained between 6.0 and 7.0 MJ/Nm3. The hot syngas containing tars produced from the gasifier was directly burned in the thermal oil heater retrofitted to vortex syngas burner to recover thermal energy, which was then utilized in the production of energy via an ORC turbine. The thermal oil heater has a thermal capacity of 7MWh and the power generation capacity of the ORC turbine is 955 kW of electricity.

Integration of ion transport membrane with conventional powerplant to enhance the plant capacity with improved power production.

Ion Transport Membrane (ITM) is an emerging technology for producing O2 by separating air in its membrane. To decrease energy loss in air separation unit and to increase the overall efficiency of a power generation unit ITM is added with the gasification unit in this model. Ceramic materials are generally used to make the ion transport membrane that produces oxygen by conducting oxygen ions at a specified temperature. Potential advantages can be gained by integrating ITM technology with power generation units as 99% pure oxygen is produced from ITM. Using ITM air separator is more beneficial compared to cryogenic air separation as ITM technology helps to improve IGCC overall efficiency and also reduces plant auxiliaries than that of power generation systems integrated with cryogenic. This paper proposed a novel and effective integration of ITM, gas turbine, HRSG system, gas clean up system and gasification unit to produce sustainable energy. Environmental impacts are considered to design this integrated power generation unit. The proposed model achieved a high gross electric efficiency of 47.58% and high net power of 296730 kW which revealed its potentiality compared to available cryogenic ASU-based combine cycle power plants.

Distributions of and environmental risks posed by Cr and Zn when co-treating solid waste in different kilns.

In order to dispose solid waste reasonably and provide reference data for solid waste co-treatment in industrial kilns, coal chemical products were co-treated in a pulverized coal furnace and refuse-derived fuel was co-treated in a gasifier-coupled pulverized coal furnace system. The distribution and environmental risks of Cr and Zn in different kilns were compared and analyzed. The Cr and Zn distributions in the solid products from the pulverized coal furnace tests were similar. Fly ash contained > 80% of the Cr and Zn. In the gasifier, cyclone dust and gasification gas contained only âˆ¼ 60% of the Cr and Zn, and gasification slag contained > 40% of the Cr and Zn. The gasification gas contained âˆ¼ 33% of the Cr and Zn volatilized. The pulverized coal furnace temperature was > 1,500 °C. Most of the Cr and Zn volatilized and then condensed, so became enriched in the fly ash. The gasifier temperature was âˆ¼ 750 °C, so less volatilization occurred and Cr and Zn became enriched in the gasification slag. The Cr and Zn concentrations in leachates of the solid products were lower than the limits of "GB 5085.3-2007". However, the Cr and Zn concentrations in the gasification slag and cyclone dust leachates were close to the limits and tens to hundreds of times higher than the concentrations in the pulverized coal furnace fly ash and slag leachates. The low temperatures and low-oxygen environments of gasifiers are not conducive to heavy metals being stable in the solid products, and the environmental risks posed by heavy metals in the solid products are high. The risks to the environment are less serious for co-treating solid waste in pulverized coal furnaces than gasifiers.

Biomass energy conversion in a gasifier for injera baking mitad application.

The performance of gasification for Injera baking was explored in this study, as well as the effects of moisture content, and primary and secondary airflow rates. Primary air is used in the reactor of a biomass gasifier, which creates syngas that is burned by secondary air on the mitad's bottom side. An average temperature of averaged 185 °C at the center and 170 °C away from the center was observed; the size of the cone determines the temperature distribution on the metal surface. The reactor's narrower cone diameter allowed for a greater temperature only in the center and a more variable baked Injera eye appearance. The cone diameter has been reduced to 0.15 m of the mitad diameter to improve the temperature distribution on the mitad surface. The gasifier temperature is 800 °C when the air/fuel ratio is 5.8 kg/kg and the moisture content of the wood is 16%. Gasification is improved by heating the primary air and changing the air-fuel ratio. The findings revealed that pre-heated air is more efficient for gasification and saves money on baking and fuel. Fuel efficiency (0.45) and time savings (0.12) were discovered in the new gasifier. Between gasification temperatures of 650 and 800 °C, an effective Injera baking temperature (170-185 °C) on the mitad surface was attained. Following the tests, the average specific wood fuel consumption (1.414 g/kg), char residue (317 g), and average Injera baking time were calculated. For each test of one baking cycle, this was found at the burning rate capability of both stoves, which is 6 kg/hr. Therefore, the fuel consumption and burning rate of fuel are depending on the amount of airflow rate.

Numerical Simulation of an Improved Updraft Biomass Gasifier Based on Aspen Plus.

In this paper, numerical investigation and optimization is conducted upon an improved updraft gasifier which is expected to overcome the weakness of conventional updraft gasifier. The comprehensive Aspen Plus model of the improved updraft gasifier is based on the RYield and RCSTR reactor. The tar prediction model is constructed, and the yield of tar is determined by the volatile of biomass and gasification temperature. The Aspen Plus simulation results agree very well with experiment results for the product yields and gasification efficiency, which shows the accuracy of the Aspen Plus model. The tar content in syngas of the improved gasifier is proved to be much lower than that of the conventional one by this model. The inflection point of the gasification efficiency occurs when air ratio is 0.25, and the optimum steam proportion in the air is 7.5%. Such a comprehensive investigation could provide necessary information for the optimal design and operation of the improved updraft gasifier.

Development and performance analysis of top lit updraft: natural draft gasifier stoves with various feed stocks.

The performance of an Ethiopian-designed and built-in gasifier stove was studied and evaluated. The water boiling test (WBT) findings are reported. This test was conducted in a controlled setting utilizing eucalyptus, bamboo, and sawdust-cow dung briquettes as test feedstocks, in accordance with WBT's 4.2.3 standard process and test manuals. Based on moisture content, the net calorific values of eucalyptus, bamboo, and sawdust-cow dung briquettes were calculated and determined to be 15.77 MJ/kg, 14.70 MJ/kg, and 15.35 MJ/kg, respectively. The efficiency of this stove was calculated utilizing those three feedstocks. As a result, the gasifier stove's efficiency having eucalyptus, sawdust-cow dung briquette, and bamboo as feedstock were 32.30 ± 0.3%, 31.5 ± 0.5%, and 26.25 ± 0.25%, respectively. This proportion did not include the ultimate charcoal production, but when this yield was employed as an energy input for additional charcoal burners, it increased to 53 ± 2%. The relationship between gasifier stove charcoal production and total efficiency is negatively related, with a linear equation of Y = - 0.7956X+ 22.766 and an R-squared value of 0.92. When compared to local stoves and foreign gasifier stoves, whose efficiency is in the range of 10 %-39% this efficiency rating was exceptional due to the fact that space between the internal and external cylinder help the secondary air to preheat before combustion and also the interior hallow cylinder help the primary air to move evenly in the vertical circular pattern for proper gasification, it will also help the gases that are produced during gasification process to move to the top part for combustion, indicating that this study can be fostered for prospective use.

Multi-objective optimization of a biomass gasification to generate electricity and desalinated water using Grey Wolf Optimizer and artificial neural network.

In the current research, an innovative biomass-based energy system is proposed for power and desalinated water production. The plant's primary components consist of a gasifier, a compressor, a heat exchanger, a gas turbine, a combustion chamber, and a Multi-effect desalination with thermal vapor compression (MED-TVC) unit. A comprehensive thermodynamic and thermoeconomic assessment is conducted on the proposed system. Besides, a parametric study is conducted to determine the effect of primary decision variables on the system performance. Multiple objective optimization using the multi-objective grey wolf optimizer (MOGWO) algorithm is applied to obtain the optimal solution with the highest exergy efficiency and the minimum amount of total cost rate. The artificial neural network (ANN) has an intermediary role in the optimization process to decrease computational time and enhance optimization speed. The relation between the objective function and decision variables is investigated, employing ANN to determine the energy system's optimum point. The generation rate for power and freshwater at the optimal point is equal to 5127 kW and 38.6 kg/s, respectively. Besides, the optimum value of the exergy efficiency and total cost rate are computed as 15.61% and 206.78 $/h, respectively. The results also revealed that the number of effects of the desalination unit does not affect the carbon dioxide emissions. Moreover, the scatter distribution of the key decision variable indicates that the air compressor pressure ratio is not a sensible variable, and their optimum points are distributed across the entire domain.

Valorisation of hazardous medical waste using steam injected plasma gasifier: a parametric study on the modelling and multi-objective optimisation by integrating Aspen plus with RSM.

The COVID-19 Pandemic has a detrimental effect on the environment related to the exponential rise in medical waste (MW). Extraction of energy from the toxic MW with the latest gasification technology instead of conventional incineration is of utmost importance to promote sustainable development. This present study investigates the processing of MW for the generation of enriched hydrogen syngas using steam injected plasma gasifier. Modelling of Plasma gasifier was performed in Aspen Plus and Model validation was done with the experimental result and, a good agreement was attained. Sensitivity analysis was implemented on MW in which the influence of gasification temperature, equivalence ratio (ER), and Steam/Biomass (S/B) on the producer gas (PG) composition, gas yield, H2/CO ratio, cold gas efficiency (CGE), and the higher heating value (HHV) was calculated. Furthermore, Response surface methodology (RSM) has been incorporated for the multi-objective optimisation of the variable gasification parameters. R2 values obtained from ANOVA for H2, CGE, and HHV are 98.62%, 99.10%, and 98.9% respectively. Using the response optimiser, the optimum values of H2, CGE, and HHV were found to be 0.43 (mole frac), 89.95%, and 7.49 MJ/Nm3 for temperature at 1560.60°C, equivalence ratio 0.1, and S/B 0.99, respectively. The observed coefficient of desirability was about 0.97.

pH-dependent release of elements from hardened and non-hardened wood ash.

Bioenergy systems that utilize clean wood feedstocks are becoming more common in western Canada to produce heat and electricity. But, wood combustion leads to ash residuals that need to be managed. Although there is growing interest in value-added uses for these wood ashes, large quantities of wood ashes are currently stockpiled or landfilled. Wood ash may be self-hardened as a pretreatment strategy to improve handling and reduce reactiveness prior to land application. This study determined aqueous concentrations of constituents released from wood bottom ash (BA) and hardened wood bottom ash (HBA) when subjected to increasing levels of acidity (pH 10 to 4). Such acidic conditions are not common but may exist during some storage, landfilling or land reclamation scenarios. Acidification of BA and HBA increased aqueous concentrations of B, Ca, Cd, Co, Cu, Mg, Mn, Ni, Sr, and Zn, whereas Cr, Hg and Mo showed decreased concentrations. Hardening reduced aqueous concentrations of As, Ca, Co, Fe, Ni, P, and Pb, in HBA compared to BA over a pH range. When properly managed, hardened and non-hardened bottom ashes generated from the combustion of clean wood should pose minimal risk to the environment.

A field study of dioxins during co-processing of hazardous waste in multicomponent slurry gasifier.

A field test was conducted to study the emission and distribution characteristics of dioxins during co-processing of hazardous waste in a multicomponent slurry gasifier (MCSG). The toxicity equivalent concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in all exhaust gas, waste water, and solid waste under both blank condition (i.e., feedstock was normal coal-water slurry) and test condition (i.e., feedstock mixed with hazardous waste and labeling reagents) were analyzed. Results showed that organic matter was fully degraded in the MCSG. The dioxin amount in the black water flash steam increased with the addition of hazardous waste and chlorine in the feedstock, and octachlorodibenzo-p-dioxins (OCDD) with the largest increase is the most easily formed monomer in dioxins. The dioxin amount in all samples was far below the standard limit in China and other countries. This indicates the low environmental risk from dioxins during the co-processing process. The dioxin distribution trend in solid, liquid, and gas phase during co-processing did not change: 86.63%-94.18%, 0.02%-0.13%, and 5.8%-13.23% of PCDDs were distributed in the exhaust gas, waste water, and solid waste, respectively, while 6.10%-22.95%, 0.59%-0.80%, and 76.45%-93.10% of PCDFs were distributed in the exhaust gas, waste water, and solid waste, respectively.

Mobility of biomass ash constituents as influenced by pretreatment and soil - An artificial weathering study.

Biomass ashes are potential soil amendments that reduce soil acidity and provide plant nutrients, but trace elements in ash may be leached from the solid phase, thereby posing environmental concerns. We determined the leachability of selected major elements, trace elements and anions from wood derived bottom ash generated from an updraft gasifier as influenced by ash pretreatments and the presence of soil via serial aqueous batch extraction. We found that self-hardening reduced initial solubility and reactivity of ash (i.e. lowered electrical conductivity), and reduced initial aqueous concentrations of Ba, Ca, Cu, Fe, Hg, Pb, Sr and Zn. But, hardening of ash increased initial aqueous concentrations of B, Cr, P, Se and SO42-. Although mixing ash into soil (5% ash by mass) generally decreased the mobility of most constituents, aqueous concentrations of P and As were increased relative to that of either ash-alone or soil-alone treatments. Overall, extract concentrations of constituents in various treatments were relatively low. Results of this serial batch extraction support the use of clean wood-derived bottom ash as a safe and environmentally suitable soil amendment.

Steam gasification of lignite and solid recovered fuel (SRF) in a bench scale fluidized bed gasifier.

The reduction of CO2 emissions and solid waste disposal are critical issues with high importance for the environmental protection. Gasification is a promising process for sustainable energy production, because it can produce a versatile gaseous fuel starting from a wide range of organic feedstocks, and with reduced greenhouse gas emissions compared to combustion. Lignite is an abundant carbonaceous resource in Europe and in this work, gasification tests were carried out with lignite and a lignite and Solid Recovered Fuel (SRF) mixture, to evaluate the quality of gas produced from co-gasification of waste materials, in view of the final uses of the gas. Experimental gasification tests were carried out in a bench scale fluidized bed gasifier at different operating temperatures; the results were evaluated in terms of gas composition, tar content and conversion rates. In addition, characterization analyses were carried out on materials before and after the tests, and pressure fluctuation signals were analysed in order to evaluate the fluidization quality of the bed inventory.

Dataset on the integrated downdraft gasifier and multi integrated gas cleaner system (IGCS) for municipal solid waste (MSW).

This experiment uses the Municipal Solid Waste (MSW) from households and traditional markets as feed materials in the Integrated Downdraft Gasifier and Multi Integrated Gas Cleaner System (IGCS). The IGCS consist of cyclone, rectangular venturi scrubber, and rotary separator. The data from the experiment show the gasification characteristics such as temperature, Low Heating Value (LHV) and tar content. The parameter consists of Air Fuel ration (AFR) at 0.48, 0.5, 0.54 scrubbing water discharge at 1.26, 2.62, 3.33 l/min, and 0.9 rotary separator using suction speed at 0.9, 3.4, 4.4 m/s, respectively. The data also show the power output of the plant and energy balance of the system. This data can be used as reference for the further development of Integrated Downdraft Gasifier and Multi-Integrated Gas Cleaner systems.

Energy production from steam gasification processes and parameters that contemplate in biomass gasifier - A review.

The transformation of biomass using steam gasification is a chemical route to facilitate changes in organic or residue supported carbonaceous substances addicted to carbon mono-oxide, hydrogen including carbon-di-oxide, etc. However, to commercialize the method of steam gasification, the hurdles persist during the gasification as well as downstream processing. This article delivers a summary of the different approaches that are described in the previous studies to achieve H2 refinement and adaptation within the gasifier system. These include advanced aspects in the research and development of biomass gasification (alike advancements under the gasification operation). The upshot of diverse operating conditions like steam flow rate, operating temperature, moisture content, gasifier agents, residence time, biomass to air, steam to biomass, equivalence ratio, etc. towards the execution of biomass gasifier. This review accomplishes that the interdependence of several issues must be considered in point to optimise the producer gas.

Impacts of stove/fuel use and outdoor air pollution on chemical composition of household particulate matter.

Biomass combustion for cooking and heating releases particulate matter (PM2.5 ) that contributes to household air pollution. Fuel and stove types affect the chemical composition of household PM, as does infiltration of outdoor PM. Characterization of these impacts can inform future exposure assessments and epidemiologic studies, but is currently limited. In this study, we measured chemical components of PM2.5 (water-soluble organic matter [WSOM], ions, black carbon, elements, organic tracers) in rural Chinese households using traditional biomass stoves, semi-gasifier stoves with pelletized biomass, and/or non-biomass stoves. We distinguished households using one stove type (traditional, semi-gasifier, or LPG/electric) from those using multiple stoves/fuels. WSOM concentrations were higher in households using only semi-gasifier or traditional stoves (31%-33%) than in those with exclusive LPG/electric stove (13%) or mixed stove use (12%-22%). Inorganic ions comprised 14% of PM in exclusive LPG/electric households, compared to 1%-5% of PM in households using biomass. Total PAH content was much higher in households that used traditional stoves (0.8-2.8 mg/g PM) compared to those that did not (0.1-0.3 mg/g PM). Source apportionment revealed that biomass burning comprised 27%-84% of PM2.5 in households using biomass. In all samples, identified outdoor sources (vehicles, dust, coal combustion, secondary aerosol) contributed 10%-20% of household PM2.5 .

Effects of biochar parent material and microbial pre-loading in biochar-amended high-solids anaerobic digestion.

This study characterises the effect of biochar (pyrolysed biomass) produced from wood pellets, wheat straw and sheep manure on high-solids anaerobic digestion (HSAD) of poultry litter. Also, pre-loading biochar with microorganisms before addition to HSADs was investigated. The addition of wood pellet biochar provides a 32% increase to the methane yield compared with control digesters. The addition of biochar produced from either wheat straw or sheep manure has detrimental effects on digester performance compared with controls. The addition of wood pellet biochar pre-loaded by placing it in a high-solids digester for 90 days provides a 69% increase in the total methane yield, 44% increase in the peak daily methane yield and a 33% reduction in the lag time compared with controls. This study highlighted a need for careful selection of parent material for biochar production and, for the first time, the opportunities to re-use wood pellet biochar for further improvements.

Characterizing dynamic relationships between burning rate and pollutant emission rates in a forced-draft gasifier stove consuming biomass pellet fuels.

Biomass is a dominant solid fuel type worldwide. Traditional biomass combustion leads to severe indoor and ambient environmental problems. Biomass pellet utilization in forced-draft gasifier stoves is regarded as an improved approach to these problems. Previous studies on forced-draft biomass stoves mainly considered average emission amounts and lacked details of the combustion properties and dynamic correlations between emissions and combustion. This study used a dynamic measurement system to test a typical forced-draft gasifier stove consuming wood pellets and maize straw pellets. Real-time fuel burning rate, that partly reflects the combustion performance, and CO, NOx and PM2.5 emission rates, over a whole combustion course, were monitored. In all tests, the burning rate rose to a high and stable level, and then sharply subsided. CO, NOx and PM2.5 emission rates varied across the combustion course. CO (NOx) emissions have a negative (positive) logarithmic linear relationship with burning rate, while no consistent relationship was observed for PM2.5 emission rate. The identified relationships between burning rate and pollutant emission rates suggest the possibility of estimating emission performance of forced-draft biomass pellet stoves based on combustion indicators, or vice versa.

Steam gasification of land, coastal zone and marine biomass by thermal gravimetric analyzer and a free-fall tubular gasifier: Biochars reactivity and hydrogen-rich syngas production.

The steam gasification properties and kinetics, products distribution and syngas composition derived from land, coastal zone and marine biomass have been studied by TGA and free-fall tubular gasifier. Volume model, shrinking core model and random pore model were applied to describe the reaction kinetics. The influence of temperature and fuel types on steam gasification in a free-fall tubular gasifier were clarified simultaneously. Results showed that gasification reactivity of reed (Re) and Sargassum horneri (Sh) chars were better than that of corn stalks (Cs) char, which mostly determined by its carbonaceous structure and the varying inorganic contents. RPM model was applied successfully to corresponding to the experimental data. Bench scale reactor test found that the steam gasification of Re gave the largest amount of gaseous product than Sh and Cs, while no liquidus formation in Sh. An increase in the temperature during gasification process boosted produced sharply total gas production yield, more yield of H2 and CO2 and less CO and CH4 from different biomass.