Carbon Dioxide and Nitrogen Infused Compressed Air Foam for Depopulation of Caged Laying Hens

Simple SummaryReportable diseases, such as avian influenza, spread rapidly among poultry, resulting in the death of a large number of birds. Once such a disease has been diagnosed at a farm, infected and susceptible birds are rapidly killed to prevent the spread of the disease. The methods to eliminate infected caged laying hens are limited. An experiment was conducted to study the effectiveness of foam made from compressed air, water, and soap to kill laying hens in cages. The study found that stress levels of the hens killed using compressed air foam in cages to be similar to the hens killed by carbon dioxide or the negative control. Hens exposed to carbon dioxide died earlier as compared to the foam methods. The authors conclude that application of compressed air foam in cages is an alternative to methods such as gas inhalation and ventilation shutdown to rapidly and humanely kill laying hens during epidemics.During the 2014–2015 US highly pathogenic avian influenza (HPAI) outbreak, 50.4 million commercial layers and turkeys were affected, resulting in economic losses of $3.3 billion. Rapid depopulation of infected poultry is vital to contain and eradicate reportable diseases like HPAI. The hypothesis of the experiment was that a compressed air foam (CAF) system may be used as an alternative to carbon dioxide (CO2) inhalation for depopulating caged layer hens. The objective of this study was to evaluate corticosterone (CORT) and time to cessation of movement (COM) of hens subjected to CAF, CO2 inhalation, and negative control (NEG) treatments. In Experiment 1, two independent trials were conducted using young and spent hens. Experiment 1 consisted of five treatments: NEG, CO2 added to a chamber, a CO2 pre-charged chamber, CAF in cages, and CAF in a chamber. In Experiment 2, only spent hens were randomly assigned to three treatments: CAF in cages, CO2 added to a chamber, and aspirated foam. Serum CORT levels of young hens were not significantly different among the CAF in cages, CAF in a chamber, NEG control, and CO2 inhalation treatments. However, spent hens subjected to the CAF in a chamber had significantly higher CORT levels than birds in the rest of the treatments. Times to COM of spent hens subjected to CAF in cages and aspirated foam were significantly greater than of birds exposed to the CO2 in a chamber treatment. These data suggest that applying CAF in cages is a viable alternative for layer hen depopulation during a reportable disease outbreak.

Simple SummaryControl of avian influenza and similar diseases in commercial poultry operations is challenging; the six major steps are surveillance, biosecurity, quarantine, depopulation, disposal, and cleaning and disinfection. Depopulation is used to cull animals that are terminally ill and to reduce the number of animals that can spread an untreatable disease. Water-based foam depopulation was used effectively during the 2014–2015 highly pathogenic avian influenza outbreak in the United States. Water-based foam, however, cannot be used effectively in caged poultry operations. Compressed air foam systems were initially developed for structural fire-fighting and, with modifications, can provide the conditions required to effectively penetrate a poultry cage and provide sufficient residence time for depopulation. In this experiment, compressed air foam was used to depopulate caged layer hens. Compressed air foam resulted in faster unconsciousness than carbon dioxide gassing. The experiment demonstrated that compressed air foam systems have promise for depopulating birds raised in cages.Outbreaks of avian influenza (AI) and other highly contagious poultry diseases continue to be a concern for those involved in the poultry industry. In the situation of an outbreak, emergency depopulation of the birds involved is necessary. In this project, two compressed air foam systems (CAFS) were evaluated for mass emergency depopulation of layer hens in a manure belt equipped cage system. In both experiments, a randomized block design was used with multiple commercial layer hens treated with one of three randomly selected depopulation methods: CAFS, CAFS with CO2 gas, and CO2 gas. In Experiment 1, a Rowe manufactured CAFS was used, a selection of birds were instrumented, and the time to unconsciousness, brain death, altered terminal cardiac activity and motion cessation were recorded. CAFS with and without CO2 was faster to unconsciousness, however, the other parameters were not statistically significant. In Experiment 2, a custom Hale based CAFS was used to evaluate the impact of bird age, a selection of birds were instrumented, and the time to motion cessation was recorded. The difference in time to cessation of movement between pullets and spent hens using CAFS was not statistically significant. Both CAFS depopulate caged layers, however, there was no benefit to including CO2.

Simple SummaryIn the face of a swine health crisis, emerging zoonotic diseases or environmental catastrophe, the mass depopulation of swine may be required to prevent the additional spread of disease and to minimize animal pain or suffering. Due to the increasing risk of global disease outbreaks, the U.S. swine industry needs feasible guidelines in place in preparation for such events. Current American Veterinary Medical Association (AVMA) approved swine depopulation methods can be difficult to implement under field conditions. Emergency depopulation using inhalants such as carbon dioxide (CO2) and nitrogen gas (N2) or the use of aspirated foam agents have been approved and conducted in poultry in the US, but are not approved for use in other livestock. Our findings, using cull sows, demonstrate that although CO2, N2 and aspirated foam combinations successfully killed all the animals, CO2 and aspirated foam did so in the shortest timeframe. In addition, the use of aspirated foam was as effective as CO2 for sow depopulation while having potential operational advantages, such as no use of lethal gases and reduced risk of associated equipment failure.The U.S. swine industry is currently inadequately prepared to counteract the increasing threat of high-consequence diseases. Although approved and preferred depopulation guidelines exist, ventilation shutdown (VSD+) is currently the only method being deployed during a state of emergency to depopulate large swine populations. However, the permitted use of VSD+ during constrained circumstances has been criticized due to raised swine welfare concerns. The objective of this study was to investigate the effectiveness of carbon dioxide gas (CO2), nitrogen gas (N2), compressed air foam (CAF), compressed nitrogen foam (CAF-N2) and aspirated foam (AF) during a 15-min dwell time on adult swine in an emergency depopulation situation. A small-scale trial using 12 sows per depopulation method showed the highest efficiency to induce cessation of movement for AF and CO2 (186.0 ± 48 vs. 202.0 ± 41, s ± SD). The ease of implementation and safety favored AF for further investigation. A large-scale field study using AF to depopulate 134 sows in modified rendering trailers showed a mean fill time of 103.8 s (SD: 5.0 s) and cessation of movement of 128.0 s (SD: 18.6 s) post filling. All sows were confirmed dead post-treatment for both trials. The implementation of AF in modified rendering trailers may allow for a safe and reliable method that allows for the expedient and mobile depopulation of both small and large numbers of sows during an emergency.

The threat of foreign animal disease outbreaks to U.S. swine herds warrants effective and readily available depopulation methods. Current American Veterinary Medical Association-recommendations using preferred physical methods for swine depopulation are unsuitable for large commercial swine herds. Our objectives were to assess and compare the efficacy and performance of three suggested large-scale depopulation methods: 1) medium-expansion water-based foam, 2) prototype high-expansion nitrogen foam and, 3) carbon dioxide gas for finisher pigs under field conditions. Out of 793 finisher pigs included in the study, 84 were implanted with bio-loggers recording electrocardiogram and pig movement data. Aversive pig behaviors were collected manually on a group level for each depopulation method. A subsample of pigs from each method were examined post-mortem for lesions and compared to a reference group of nine pigs euthanized with pentobarbital. Depopulation method assessments included container fill time, the number of aversive pig behaviors observed during depopulation, overall pig movement intensity, time to cessation of movement, time to and cause of cardiac arrest, and respiratory lesions. No difference in fill times between water-based foam and nitrogen foam was observed. The total number of aversive swine behaviors was higher for carbon-dioxide compared to both foam methodologies (P < 0.01). The total pig activity was higher in water-based foam compared to nitrogen foam (P = 0.02) and carbon-dioxide methods (P = 0.01). The mean time to cessation of movement was significantly shorter for water-based foam and nitrogen foam compared to carbon-dioxide (P < 0.01). No differences in cardiac activity were observed. Water-based foam pigs had increased odds of distal trachea occlusions compared to other methods. All depopulation methods demonstrated high efficacy with a 100% mortality rate. The results from this study support large-scale water-based foam, nitrogen foam and carbon dioxide as viable AVMA depopulation guideline candidates for swine.

: The Headquarters Air Force Civil Engineer Support Agency (HQ AFCESA) is finalizing the specifications for the next generation aircraft rescue and fire fighting vehicle for deployed locations. AFRL has proven that ultra high pressure (UHP) technology improves fire fighting efficiency more than 300 percent than conventional low pressure systems. Five P-19 fire trucks were modified with a new pumping system capable of producing UHP, compressed air foam (CAF) and CAF with dry chemical. Five bases with hydrocarbon training pits were chosen to participate including Dyess, Ellsworth, Mountain Home, Davis-Monthan and Tyndall. Each base was provided with training for maintaining the new UHP pump and effective use of each fire fighting system. Two firefighters were chosen to operate the vehicle and evaluations were completed including foam quality, throw distance, pump cycle testing, limited cold weather operation and live fire testing. Several design issues were identified during testing, which were resolved during testing. Field evaluations showed that UHP technology provided improved efficiency similar to that observed under laboratory conditions. AFCESA is currently implementing this technology in new vehicle purchases.

This experimental study compares the flame structure, temperature, and soot formation characteristics of normal (NDFs) and inverse diffusion flames (IDFs), evaluates the effect of CO2 addition, and isolates the thermal and dilution effects of CO2 and N2 addition on soot formation in IDFs. A hyperspectral imager using the TR-GSVD algorithm measures IDFs with different CO2 addition (XD) in the oxidant, with N2 addition as the comparison. In contrast to NDFs, IDFs have an opened tip, and the visible flame height and flame width decrease as XD grows. IDFs have a higher peak temperature than NDFs, but their peak soot volume fraction is substantially lower. Compared with N2 addition at the same XD, CO2 addition narrows IDFs and makes the reaction zone visible, and the peak temperature of CO2 addition is 350 K lower than that of N2 addition. The suppression effect of CO2 on soot formation is more potent than N2, with a soot formation rate of 30% that of N2 addition and a soot loading of 20–60%. The activation energy of soot formation reaction with CO2 addition is higher than N2 addition. The isolating results reveal that the thermal effect contributes to the main suppression effect of CO2 addition on soot formation, while the dilution effect of N2 addition is stronger than its thermal effect.

This report describes an initial step to quantify the effectiveness of waterbased compressed air foam (CAF) generated with a synthetic hydrocarbon-based surfactant.

Foam enhanced oil recovery techniques involving super critical CO2 with surfactants are becoming popular these days due to the ability of foam to appreciably overcome problems like gravity override and viscous fingering. Foam lowers the mobility of the injected fluid consequently increasing the sweep efficiency. Several studies have been conducted to study the differences between CO2-foam and N2-foam which report that CO2 is unable to generate strong/stable foam above its supercritical point (1100 psi, 31°C) whereas N2-foam is unaffected by the increase in pressure and temperature. However, an in-depth investigation to test the stability of mixed CO2/N2–foam has not been carried out yet especially in sandstone porous media. In this work, a novel mixed CO2/N2-foam system was tested for stability for the first time in foot long sandstone cores using an amine oxide-based amphoteric fluorosurfactant. The concentration of the surfactant solution was kept at 0.15 vol% which is above its critical micelle concentration (CMC) of 0.10 vol% that was determined through interfacial tension (IFT) measurements between sc-CO2 and surfactant solution at 1500 psi and 50°C. Foam flooding experiments were then performed at a temperature of 50°C and back-pressure of 1500 psi in which co-injection of sc-CO2, N2 and 0.15 vol% surfactant solution was carried out. N2/CO2 ratio was varied between 0-20% and in-situ foam quality was varied from 0.70 to 0.95. Each foam quality was maintained until steady state conditions prevailed. Strong foam or weak foam was characterized based on pressure drop across the core. The results of this study show that as N2/CO2 ratio is increased from 0 to 20% an increased pressure drop across the core is observed even when the total injection rate is held constant leading to the conclusion that addition of N2 to sc-CO2 was able to generate a stronger (more viscous) foam. Average steady state pressure drop for 0.70 foam quality was 60 psi at 0% N2 and 140 psi at 20% N2 whereas for 0.80 foam quality it was 130 psi at 0% N2 and 170 psi at 20% N2. However, at 0.90 and 0.95 foam qualities average steady state pressure drop reduced to 125 psi at 0% N2 and 150 psi at 20% N2 implying that effect of N2 was most profound for 0.70 foam quality and least for 0.90 and 0.95 foam quality. Also, foam quality of 0.80 exhibits highest pressure drop with and without addition of N2. Steady state pressure drop was stable for about 0.5 PV of injection at all foam qualities indicating high foam stability with this surfactant. This study provides a new and viable alternative for sc-CO2-foam flooding highlighting the effectiveness of addition of N2 to the foam system even at small proportions. The tested mixed CO2/N2-foam system could strengthen the potential of sc-CO2 EOR.

Effect of N2 and CO2 on explosion behavior of H2-Liquefied petroleum gas-air mixtures in a confined space

The Editors’ Choice

Comparison of water-based foam and carbon dioxide gas emergency depopulation methods of turkeys

The United States’ swine industry is under constant threat of foreign animal diseases, which may emerge without warning due to the globalized transportation networks moving people, animals, and products. Therefore, having disease control and elimination protocols in place prior to pathogen introduction is paramount for business continuity and economic recovery. During extraordinary circumstances, it may become necessary to depopulate large populations of animals, including swine, as a disease containment measure. Currently approved depopulation methods for swine present significant logistical challenges when scaled to large populations or performed in field conditions. In the United States, water-based foam is currently approved for poultry depopulation, and recent field studies demonstrate water-based foam is an effective depopulation alternative for swine. While effective, the speed at which water-based foam induces loss of consciousness prior to death, a major welfare consideration, has not been adequately investigated. In this study, 12 nursery pigs were terminated using water-based medium-expansion foam to quantify the time to induce loss of consciousness and ultimately brain death. Each pig was implanted with subdermal electrodes to capture electroencephalographic data, placed in a body sling, and suspended in a plastic bulk container that was subsequently filled with water-based foam. Electroencephalographic data was recorded for 15 min, during which the pigs remained immersed in the water-based foam. Conservatively, average (± SD) time to unconsciousness and brain death was 1 min, 53 s ± 36 s and 3 min, 3 s ± 56 s, respectively. The relatively rapid loss of consciousness compared to other methods limits the amount of distress and is overall a positive finding for the welfare of the pigs that might be depopulated with water-based foam. The findings of this study add additional evidence supporting the use of water-based medium-expansion foam for an emergency depopulation of swine.

Mobile compressed-air-foam (CAF) systems represent a new type of fire suppression system, which is gaining popularity among fire services. Properly engineered CAF systems produce superior quality foam with high momentum. However, until now, there has not been a study to systematically evaluate the fire suppression effectiveness of mobile CAF systems. NRC has carried out a project to evaluate the effectiveness of a mobile CAF system in suppressing fully developed compartment fires. Several full-scale compartment fire tests were conducted to compare the fire suppression performance of a manually applied CAF system with that of hose stream application using water alone and using water-foam solution, under similar conditions. The study showed that a CAF system is much more effective in suppressing the compartment fire compared to hose stream application with water only or with foam-water solution. A CAF system with a 95 L/min (25 GPM) water flow rate suppressed the test fire better than the hose-stream application with water only or with foam-solution using 360 L/min (95 GPM). The CAF system suppressed the fire and cooled down the fire compartment (to 200°C) much quicker than the water alone or foam-solution. Also, the total amount of water used to control the test fire was much less with the CAF system than with the water alone or foam-solution.

Existing portable foam extinguishers generate fire-fighting foam at high pressures with the aid of an air aspirating nozzle. This system could encounter several limitations at the point of application such as poor foam quality due to the use of fire contaminated air for foam generation and insufficient momentum to reach the seat of fire. Research has shown that by incorporating compressed air into a portable foam system, the integrated foam system could generate superior quality foam with high momentum when properly installed with the right components. Several studies had been conducted on the extinguishing performance of compressed air foam systems on multiple fire types, both for small and large fires. Compressed air foam systems mitigate exposure of the operator to heat and provides faster knockdown of the fire plume as compared to air-aspirated foam because of its stronger stability and rheology. Since the expansion ratio of the foam can be regulated to combat specific fire types and sizes, compressed air foam systems can be utilized in protecting a variety of equipment of varied sizes.The aim of this study is to investigate the discharge characteristics of a portable compressed air foam at low pressure. For this study, the requirements of NFPA 10 and CAN/ULC-S508 for a new system were used to determine the feasibility of the system.The effect of air pressure on the expansion ratio of the foam was investigated with foam concentrate ranging from 2% to 4% for three different hoses with lengths of 1-m, 2-m and 3-m. Pressure used ranged from 1.72 bar to 5.52 bar. The 3% and 4% solution for the 2-m hose and 3-m hose exhibited similar trend of a rise and fall with pressure by generating fluid foam of medium expansion ratio in the range of 19 to 28. However, the expansion ratio of 3% solution and 4% solution for the 1-m hose increased monotonically with increasing pressure and generated wet foam of low expansion ratio in the range of 8 to 15. While low expansion foams are effective in extinguishing liquid pool fires, medium expansion foams are used for structural protection due to its slow drainage time and its ability to adhere to sloped, vertical, horizontal and slippery surfaces.Discharge range tests were conducted to investigate the horizontal projection of the foam from the nozzle at a height of 0.9m above the ground. The test was conducted in an open space with little interference of wind. Visual record of the maximum discharge range was taken at intervals. The foam from the 1-m hose projected from 1 m at 2.42 bar to 2.4 m at 5.52 bar while the foam from the 2-m hose projected from 1.8 m at 2.42 bar to 4.5 m at 5.17 bar. Likewise, the foam from the 3-m hose with an initial discharge of 1.85 m at 2.41 bar increased progressively to above 4.5 m at 4.83 bar. The tests demonstrated the relationship between pressure and the momentum of the foam, showing that an increase in pressure leads to an increase in the range covered. Furthermore, flow rates at different pressures were investigated using 3% foam solution with a 2 m hose. The flow rate of the foam ranged from 8 g/s to 20 g/s at 1.93 bar and 5.24 bar respectively, indicating linear progression with pressure. The flow rates correspond to application times of 244 and 102 seconds respectively for the 2-liter solution. Overall, all foams tested met the requirements of the CAN/ULC-S508 standard.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 172620, “Successful Implementation of CO2-Energized-Acid Fracturing Treatment in Deep, Tight, and Sour Carbonate Gas Reservoir in Saudi Arabia That Reduced Freshwater Consumption and Enhanced Well Performance,” by Ataur R. Malik, SPE, Alaa A. Dashash, Saad M. Driweesh, SPE, and Yousef M. Noaman, SPE, Saudi Aramco, and Eduardo Soriano, SPE, and Alfredo Lopez, Halliburton, prepared for the 2015 SPE Middle East Oil and Gas Show and Conference, Manama, Bahrain, 8–11 March. The paper has not been peer reviewed. Carbon dioxide (CO2) with 30% foam quality (FQ) has been introduced for the first time during acid fracturing treatments in a tight, sour, high-pressure/high-temperature carbonate gas reservoir in Saudi Arabia to reduce consumption of fresh water, minimize reservoir damage, reduce the flowback period, and eliminate the need for nitrogen lifting with coiled tubing. The addition of liquid CO2 to hydrochloric acid (HCl) in quantities sufficient to produce emulsion allows live acid to retard and penetrate much deeper than HCl alone. Introduction Gases were introduced to the oil and gas industry primarily as an aid to recover pumped stimulation fluids. This application still accounts for the majority of use of nitrogen and CO2. Special applications, such as foaming stimulation fluids, have reduced consumption of the liquid phase significantly. Stimulation activities have been increasing dramatically in Saudi Arabia. During each stage of fracturing stimulation in Saudi Arabia, up to 3,000 bbl of groundwater is used. Up to 70% of that groundwater consumption can be reduced through the CO2-foam fracturing treatment. The application of CO2 also reduces the flowback period and eliminates the need to perform coiled-tubing nitrogen lifting, which is a unique requirement for tight and depleted reservoirs. The addition of liquid CO2 to HCl in quantities sufficient to produce viscous foam (emulsion) is one of the more significant improvements in recent years. The addition of CO2 to acid accomplishes the following: It increases the viscosity of the commingled fluid. It controls leakoff of acid. Most CO2 foamed-acid treatments are performed at matrix rates. It can easily be pumped at fracturing rates. The fracture length is determined by acid reaction rate, injection rate, fracture width, and rate of fluid loss from the fracture to the formation. It dramatically increases the efficiency of HCl. Laboratory testing with cores from the canyon reef formation indicates an improvement in penetration of live acid of almost ninefold over a conventional acid system. It cleanses the formation. Many formations are only partially soluble in HCl. The energy and viscosity of the foamed acid aid in removal of these undissolved fines from the formation. The CO2 also strips hydrocarbon from the rock, exposing it to dissolution by the acid. It improves formation permeability by the removal of stimulation and connate fluids. It dissolves more rock. An 80%-quality foam (only 20% of the volume is acid) has been proved to remove as much rock as when the entire solution is acid. It reduces or eliminates the need for swabbing. The load to recover is significantly lower than a conventional-treatment volume. The balance of the treatment (the CO2) will vaporize and aid in the recovery of undissolved fines, spent acid, and flush volumes. Because CO2 at the surface is above the critical pressure (1,071 psi) but below the critical temperature (87.8°F), CO2 is pumped into the wellbore as a liquid. It remains a liquid until heated by the formation downhole. Conversion of CO2 to a gas downhole causes no disruption of the two-phase fluid because supercritical CO2 has a high density and no abrupt expansion of CO2 occurs.