Traditional buoyancy materials generally use polyurethane foam, epoxy foam or other foam plastic, although the cost is low, but the pressure strength is low, soaking for some time, will lose water buoyancy, the use of poor reliability. People began to develop lightweight high-strength solid buoyancy materials to replace the traditional buoyancy materials for deep-sea resource exploration and mining.
At present, the use of high-performance hollow glass beads filled with polymer synthesis of deep-sea high-strength buoyant material has been applied. It is made of epoxy resin
As the substrate, filled with a certain amount of high-performance hollow glass beads and other additives into a light buoyant material. In the deep sea oil and gas field exploration and operations to reflect the light, resistant to seawater corrosion, dimensional stability, high strength, good insulation and many other advantages.
1977 Charles .G. Wade US Atlas Powder Company proposed not adding the sensitizer, only 1 on the 6th detonators reliable emulsion explosives detonated. Its main feature is the use of sensitization of hollow glass microspheres.
Thin-walled hollow glass beads from sodium borosilicate material with a special process, closed the tiny sphere, the sphere inside the parcel certain amount of gas, its specific density, low thermal conductivity, low oil absorption, particle size and chemical composition controllable superior performance, which makes it very suitable as emulsion explosives sensitizers.
Hollow glass microspheres uniformly distributed stable formation of numerous tiny bubbles of space in explosives. In the role of external initiation impulse, each bead by adiabatic compression local temperature form burning point, and detonated outside the mechanical energy is focused on those burning point is at a temperature high enough to cause burning and oil phase oxidant the violent exothermic chemical reactions such as decomposition, to detonation.Internal phase emulsion explosive matrix supersaturated solution, the density is large, liquid beads were separated by the film; the Foreign Secretary for the film, the density is relatively small, in the long-term storage in the aqueous phase has a tendency to sink, the oil phase has a floating trend, final lead to breaking. Most of hollow glass microspheres diameter between 10μm to 150 μm, and a matrix of internal phase droplet diameter of 10-1μm to 1μm, Foreign Minister film thickness of 10-3μm to 10-2μm.After addition of cenospheres, nearly one-third of the space of the substrate surface granularity “huge” hollow microspheres occupied surface of each bead around the oil droplets are associated with many closely together. They play the role of care afloat stabilizer.
In summary, hollow glass beads is a multifunctional additive in emulsion explosives.
For example: by adding water dilution, plus hollow ceramic microspheres method, add the foam method. Dilution water and add the cement foam-regulating unstable performance. Plus hollow ceramic microspheres law, and hollow ceramic beads themselves strong enough, in the slurry injection wells can break, resulting slurry density rises.And in the deep mining of oil, adding high-performance hollow beads of grout has a certain fluidity in the process of injection wells, grout injection wells, it can quickly condense, and reached a considerable strength in the short term, the hardened cement pasteIt has good stability and impermeability, corrosion resistance and so on.Temperature and pressure at the bottom of the well with the depth of enhancements and improved every depth 100m, an increase of about 3 degrees Celsius temperature, pressure increase 1.0-2.0mpa. Depth of 7000 meters above the bottom hole temperature up to 200 degrees Celsius, and pressures up to 125mpa.Thus high temperature and pressure, to influence various properties of cement, oil well cement production and use of the most important issues. The strength of the cement slurry high temperature decreased significantly. Added with cenospheres slurry, not only to reduce the density and can withstand prolonged high pressure and high temperature strength, this lightweight cement outperforms other conventional light cement.
Sorter is using gravity separation, sorting consists of three sizes settlement box. In the lower portion of each settling tank, are provided with discharge means, when the gas stream containing fly ash from the intake pipe into the settling tank, since the gas flow passage cross section is increased, the gas flow rate drops quickly, fly ash by itself the force of gravity. Part of the gradual drop in the settling tank, according to the principles and other lower, heavier coarse particles, honeycomb vitreous quartz, mullite, solid beads, iron beads and large particles of carbon particles were mostly settled in the sorter within . There are some small hollow glass beads, beads, etc. Superfine into the air separator.
By the action of the separator is in the gas stream during rotation of the centrifugal force on the particles in the inertia, so that particles are separated out from the gas stream. The main form of cyclone separator group, by sinking down box channel tiny hollow beads into the air separator, sorting through a two-stage cyclone group can most small cenospheres sorting out, the remaining very small amount of ultra-fine beads and finally with the air enters the collector.
Collector terminal sorting apparatus, it is both the purification apparatus is recovered ultrafine microbeads collector. Process uses a pulse bag collector, it is not selected by the separator down the majority of ultrafine beads collected.
Currently, deep-sea exploration and development mainly in diving technology, the use of submersible, underwater robots in the deep sea observation, measurement, sampling, install the necessary instruments and facilities, operations, and other underwater.In order to increase pressure resistance, structural stability dive drag body, diving and underwater robots, and to provide sufficient net buoyancy, people started to develop high-strength solid buoyant material to replace the traditional ball buoyancy and pressure buoyancy tube.High strength solid buoyant material is an important part of modern diving technology, to ensure the buoyancy of submersible, submersible increased payload, reduce its dimensions plays an important role.
When the actual buoyancy material requires long-term immersion in water, the requirements of its water, pressure, corrosion and impact. In particular, for each additional 100m depth in the ocean, the pressure will increase by an object about 10 atmospheres ie 1MPa.Therefore, advanced solid buoyancy material should be both light and strong, that is, in the case of maintaining a low density, a substantial increase in compressive strength, but often reduced density while pressure is also reduced.
Over the years, in order to improve performance and storage stability of detonation of emulsion explosives, and other people in the formulation of emulsion explosives, sensitizer and equipment of various aspects of the research.
Density adjustment is one of the key production of emulsion explosives operational aspects, the choice of density modifiers directly affects the detonation performance and storage stability of emulsion explosives.At present, more commonly used emulsion explosive density modifiers of chemical blowing agent and expanded perlite, the disadvantage of the former is difficult to control the density of explosives, short shelf life, and there aftereffect; the latter vulnerable to its size disadvantage is explosive, strength and limit oil resistance, low detonation performance, short shelf life.The introduction of hollow glass microspheres in the emulsion explosives, to overcome the above drawbacks, greatly improving the performance of explosive detonation and significantly improved storage stability. In other countries, like the United States, Britain, Sweden and Japan and other countries has been the use of hollow glass microspheres as emulsion explosive density modifiers.However, due to expensive imported glass beads in the country has been unable to universal. With the advent of homemade beads, the current domestic production of emulsion explosives plant has been gradually promoting the use of hollow glass beads.In order to increase the detonation sensitivity of the emulsion base, people have proposed adding explosive class sensitizing agents and other organic amine nitrate sensitizer.
In the sky into the sea are indispensable, this little beads naturally become the focus of attention. Prior to the development of the mine hospital market, in full compliance with the international community to provide the technical requirements of the hollow glass beads manufacturers mainly US 3M Company. But the United States for the export of raw materials hollow glass microspheres are strictly limited. Although some units costing tens of millions of domestic production and the introduction of foreign technology and equipment, trying to develop the production of hollow glass beads, but the lack of key technologies, regardless of quality or performance of different specifications, can not be compared with foreign products.
In 2008, the hospital began to explore innovative high performance hollow glass microspheres in cooperation with Chinese Academy of Sciences, 2009 related to the preparation and full production has basically ended.
Because of the higher strength requirements, so diving with solid buoyant material commonly used buoyancy regulating medium and high strength resin composite.Especially in the field of application of the deep sea is a great depth, to ensure buoyancy material has high compressive strength and greater security and reliability, often only use hollow glass microspheres with a polymer composite syntactic foam.At the same time, in order to obtain a low density syntactic foam, improve its buoyancy, volume content of hollow glass microspheres are high, reaching 60 to 70%.Thus, hollow glass microspheres have a significant impact on diving performance benefits of solid materials. It can be said that only the hollow glass microspheres base low density, high strength prepared on order to get a good solid buoyant material.
High strength hollow glass microspheres with diameter no more than 1 mm are attractive for hydrogen storage and transport. Microspheres were made by drop tower techniques with 150-250 μm diameter and 0.9-4.0 μm membrane thickness . By immersion in high pressure hydrogen for a period of time at an elevated temperature the microspheres could bu filled with hydrogen. The hydrogen pressure was equal to that of gas-filled chamber at 350℃ for 6-10 h. With the help of Fick’s first law and the ideal gas law the pressure in the microspheres could be calculated. Based on the Arrhenius expression, permeability conefficient decreased as temperature dropped. The half-life time for hydrogen retention in hollow glass microspheres was about 40-50 d at room temperature. The maximun hydrogen pressure could reach 20-25 MPa in the hollow glass microspheres with 200 μm diameter and 2 μm membrane thickness. The hydrogen mass fraction was 13% to 16%.
Titanium doped hollow glass microsphere preparation process
Sol-gel technology is metal organic or inorganic compound as precursor, uniform and hydrolysis under liquid phase polycondensation reaction, after solution, sol and gel and curing, after heat treatment and the technological process of the solid oxide or other compounds.Sol-gel technology provides a low temperature chemical new ways of cutting and control in the microstructure of the material. Tell from the principle of doping, titanium doped glass sol – gel titanium doped glass – titanium doped dry gel particles – titanium doped hollow glass microspheres in furnace pelletization process each link of uniform doping control technology properly, can realize Ti – the titanium HGM uniform doping.
Doped Ti hollow glass microspheres prepared in the furnace
Doped Ti of hollow glass microspheres pelletization process inside the furnace is in a composite of high temperature oven dry gel microsphere was prepared. Doped titanium dry gel particles from the feed zone into free fall after high temperature, in turn after absorption of heat, encapsulation, foaming, refining, cooling process, the final settlement in the collection the collection vessel.
