6 research outputs found
Core-scale characterisation of flow in tight Arabian formations
Peer reviewedPublisher PD
Novel metered aerosol valve
The design and performance of a new valving mechanism for portable pressurized spraying devices is described, where
the propellant in the device is a safe gas (so-called compressed gas) propellant rather than the current liquefied gases all
of which are either volatile organic compounds or greenhouse gases. The valve sprays a fixed volume of liquid when the
spraying actuator is depressed, as is essential used medical sprays, such as pressurized metered dose inhalers and nasal
sprays, and also for automatic (wall-mounted) aerosol delivery systems for air-fresheners, insecticides and disinfectants.
For ‘compressed gas’ aerosol formats, there is no flash vaporization of propellant so that pumping liquid from a metering
chamber and atomization to form a spray must be achieved entirely by designing some means of using the pumping action
of the gas in the container to act upon the liquid in the metering chamber. The new design utilizes a loosely fitting
spherical piston element and a simple arrangement of a concentric housing and a moveable valve stem, such that liquid
flow paths between the different elements are automatically closed and opened in the correct time sequence when the
valve stem is depressed and released. Spraying data show excellent repeatability of liquid sprayed per pulse throughout
the lifetime of device and drop sizes that are acceptable for devices such as air-fresheners and nasal sprays. The valve has
only one additional component compared with liquefied gas metered valves and can be straightforwardly injection
moulded. As will be explained, previous attempts failed due to expense, complexity and unreliability.
Keywords
Aerosol valve, spray metering, insert, inhaler, air-freshene
Next generation of consumer aerosol valve design using inert gases
The current global consumer aerosol products such as deodorants, hairsprays, air-fresheners, polish, insecticide, disinfectant
are primarily utilised unfriendly environmental propellant of liquefied petroleum gas (LPG) for over three decades.
The advantages of the new innovative technology described in this paper are: (i) no butane or other liquefied
hydrocarbon gas; (ii) compressed air, nitrogen or other safe gas propellant; (iii) customer acceptable spray quality and
consistency during can lifetime; (iv) conventional cans and filling technology. Volatile organic compounds and greenhouse
gases must be avoided but there are no flashing propellants replacements that would provide the good atomisation and
spray reach. On the basis of the energy source for atomising, the only feasible source is inert gas (i.e. compressed air),
which improves atomisation by gas bubbles and turbulence inside the atomiser insert of the actuator. This research
concentrates on using ‘bubbly flow’ in the valve stem, with injection of compressed gas into the passing flow, thus also
generating turbulence. Using a vapour phase tap in conventional aerosol valves allows the propellant gas into the liquid
flow upstream of the valve. However, forcing bubbly flow through a valve is not ideal. The novel valves designed here,
using compressed gas, thus achieved the following objectives when the correct combination of gas and liquid inlets to the
valve, and the type and size of atomiser ‘insert’ were derived:
1. Produced a consistent flow rate and drop size of spray throughout the life of the can, compatible with the current
conventional aerosols that use LPG: a new ‘constancy’ parameter is defined and used to this end.
2. Obtained a discharge flow rate suited to the product to be sprayed; typically between 0.4 g/s and 2.5 g/s.
3. Attained the spray droplets size suited to the product to be sprayed; typically between 40 mm and 120 mm
Solubility trapping as a potential secondary mechanism for CO2 sequestration during enhanced gas recovery by CO2 injection in conventional natural gas reservoirs : an experimental approach
This study aims to experimentally investigate the potential of solubility trapping mechanism in increasing CO2 storage during EGR by CO2 injection and sequestration in conventional natural gas reservoirs. A laboratory core flooding process was carried out to simulate EGR on a sandstone core at 0, 5, 10 wt% NaCl formation water salinity at 1300 psig, 50 °C and 0.3 ml/min injection rate. The results show that CO2 storage capacity was improved significantly when solubility trapping was considered. Lower connate water salinities (0 and 5 wt%) showed higher CO2 solubility from IFT measurements. With 10% connate water salinity, the highest accumulation of the CO2 in the reservoir was realised with about 63% of the total CO2 injected stored; an indication of improved storage capacity. Therefore, solubility trapping can potentially increase the CO2 storage capacity of the gas reservoir by serving as a secondary trapping mechanism in addition to the primary structural and stratigraphic trapping and improving CH4 recovery