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Potential risk factors for solar polysilicon production process

Different from those used to electronics and solar cells, monocrystalline silicon, is also different from amorphous silicon thin-film devices and solar cells, polysilicon is made up of tiny silicon materials. Major polysilicon producer Hemlock Semiconductor, OCI, WACKER (Wacker Chemie), GCL-poly energy, and REC, LDK Solar, MEMC, and some smaller producers.

Polysilicon industry is developing rapidly, and levels above 1000t polysilicon production plant were built. However, polysilicon production process, hydrogen, chlorine, trichlorosilane and silicon and other harmful substances, and there are fire, explosion, poisoning, suffocation, electric shock injuries and many other risk factors.

Potential risk factors in the production process

, Polysilicon production process of harmful gas

Harmful substances produced in the polysilicon production process of chlorine gas, hydrogen, Silicon, hydrogen chloride, trichlorosilane, main risk characteristics are:

1. hydrogen gas: mix can form explosive mixtures with air, heat or open flame or explosion. Gas is lighter than air, when indoors use and storage, leakage increased stranded roof difficult to discharge, when Mars will cause an explosion. Halogens such as fluorine, chlorine, bromine and hydrogen will react violently.

2. oxygen, combustible materials, combustible matter combustion and explosion of one of the essential elements and oxidation of most active substances. And combustible (such as acetylene and methane) forms explosive mixtures.

3. chlorine: a pungent odor and can be generated with a number of chemical explosions or explosive material. Almost all metallic and non-metallic corrosion. Are highly toxic. Is a strong irritant gases.

4. hydrogen chloride: anhydrous hydrogen chloride is non corrosive, but when in contact with water, are corrosive. Can react with reactive metal powders, releasing hydrogen gas. Cyanide can produce highly toxic hydrogen cyanide gas.

5. three hydrogen Silicon chlorine: open flame burning strongly. Subject to high thermal decomposition may produce toxic chlorine gas. Reacts with oxidants, are a fire hazard. Very volatile and fumes in the air, in contact with water or water vapour can generate heat and toxic corrosive smoke. Combustion (decomposition) products: hydrogen chloride, silica.

6. Silicon tetrachloride: heating or hot water liberation, release toxic corrosive smoke.

7. hydrofluoric acid: corrosive, very strong. H vesicant immediately burned. Can react with bare metal and releases hydrogen with air to form an explosive mixture.

8. a nitric acid: strong oxidizing. And combustible (such as benzene) and organic matter (such as sugar, cellulose) exposure will react violently, even cause fire. With alkali metals react violently. Has strong corrosion resistance.

9. the nitrogen: in case of high fever, increased pressure within the container. Cracking and danger of explosion.

10. hydrogen fluoride: highly corrosive. In case of high fever, increased pressure within the container, is in danger of cracking and exploding.

11. sodium hydroxide solution: this product is non-combustible, with strong strong corrosive, irritant can cause the human body burns.

Second, electric shock, other risk factors such as mechanical damage

Fire, explosion, poisoning is polysilicon projects in major danger and harmful factors in production, in addition, there is electric shock, mechanical damage, corrosion, dust and other hazardous and harmful factors. Are:

1. preparation of hydrogen: electrolyzer, hydrogen, and oxygen tanks, fire and explosion, electric shock and mechanical damage.

2. hydrogen chloride synthesis: synthesis furnace of hydrogen chloride, chlorine and hydrogen gas buffer tanks, fire and explosion, poisoning, electrocution.

3. the three Silicon-hydrogen chloride synthesis: three Silicon-hydrogen chloride synthesis furnace, synthesis gas scrubbers, feeding machine, fire and explosion, electric shock, poisoning, corrosion, mechanical damage and dust.

4. the synthesis gas separation: mixed gas scrubber, hydrogen chloride absorption tower, Tower, the mixed gas compressor hydrogen chloride resolved, fire and explosion, electric shock, poisoning, corrosion, mechanical damage.

5. separation of chlorosilanes: distillation, reboiler, condenser air, fire and explosion, electric shock, poisoning, corrosion, mechanical damage.

6. the three hydrogen Silicon chlorine reduction: three hydrogen Silicon chlorine carburetor, reduction furnace, reduction furnace cooling water circulation pumps, fire and explosion, electric shock, poisoning, corrosion, mechanical damage.

7. restore gas separation: mixed gas scrubber, gas compressors, hydrogen chloride absorption towers, fire and explosion, electric shock, poisoning, corrosion, mechanical damage.

8. hydrogen-Silicon tetrachloride: Silicon tetrachloride carburetor, hydrogen furnace, fire and explosion, electric shock, poisoning, corrosion, mechanical damage.

Based on the above analysis, it is the main potential risks of fire and explosion, chemical poisoning, harmful factors in terms of technology, equipment, facilities and protection problems and defects, is very likely to occur, it should be for reasons that may occur and take preventive measures to actively exclude.

Primary prevention measures are: automatic control system for production use, and improve the standard of control; in chlorine, hydrogen chloride, trichlorosilane Silicon Silicon chloride, hydrochloric acid, easy to leak part of fresh air and sets flammable and toxic gas detection and alarm system; personnel issued qualified for the job for antivirus, dust-proof and burns and other protective equipment to avoid risks of polysilicon.

How does solar energy convert into biomass energy and mechanical energy

How does solar energy convert into biomass energy and mechanical energy(III)

Solar energy-biomass energy conversion

By photosynthesis in plants, solar energy synthesis of organic matter to carbon dioxide and water (bio-energy) and give off oxygen. The process of photosynthesis is the largest on Earth to convert solar energy, fuel is an ancient and modern human photosynthetic fixation of solar today, at present, the photosynthetic mechanism is not fully understood, energy conversion efficiency of only a few hundredths, in future, its mechanism is of great theoretical significance and practical significance of the study.

Solar energy-mechanical energy conversion
In early 20th century, Russian physicist, experimental proof of light pressure. 20, the Soviet physicists suggested that the great solar sail in space, can move the ship forward under the pressure of sunlight, solar energy directly into mechanical energy. Scientists estimate that in the next 10-20 years, solar sail vision can be achieved. In General, conversion of solar energy to mechanical energy, intermediate process for indirect conversion is required.

How Does solar energy convert into hydrogen energy

How Does solar energy convert into hydrogen energy(II)

Hydrogen is a high quality source of energy. Decomposition in water or any other ways in which solar energy can be converted to hydrogen energy, hydrogen production from solar energy, it is mainly as follows:

(1) solar-hydrogen from electrolysis of water. Hydrogen from electrolysis of water is now more widely used and more mature, more efficiently (75%-85%), but the power in both conventional hydrogen, from the energy use of gain. Therefore, only after the significant drop in the cost of solar power, large-scale hydrogen from electrolysis of water can be achieved.

(2) solar thermal hydrogen production from water decomposition. Water or steam heated to above 3000K, the hydrogen and oxygen in the water can break down. Efficient hydrogen production by this method, but requires a high concentration can achieve high temperatures, hydrogen production are generally not used in this way.

(3) the solar thermochemical cycle for hydrogen production. In order to reduce the high temperature solar direct thermal water splitting for hydrogen production requirements, developed a thermochemical cycle for hydrogen production methods, that is, in the middle of adding one or more water, then heated to a lower temperature, going through various stages of response, ultimately splitting water into hydrogen and oxygen, and intermediate consumption, recyclable. Thermochemical cycle decomposition temperature along the lines of 900-1200K, it was a rotating parabolic mirror concentrator for easy temperature, decomposition of water efficiency in the 17.5%-75.5%. Intermediate restores are the main problems that exist, even if restoring by 99.9%-99.99%, and would also like to add a 0.1%-0.01%, which will affect the price of hydrogen, and environmental pollution.

(4) solar photochemical hydrogen production from water decomposition. This hydrogen thermochemical cycle for hydrogen production with such similarities, adding a photosensitive substance in water as a catalyst, increasing long wavelength absorption of light energy to the Sun, use of photochemical reactions of hydrogen. Japan people use iodine sensitivity to light, devised including photochemical, thermal response an integrated hydrogen production processes, hydrogen 97 liters per hour, efficiency of up to 10% per cent.

(5) the solar photoelectrochemical cells hydrogen production from water decomposition. 1972, Japan this more health first people uses n type Titania semiconductor electrode for anode, and to Platinum black for cathode, made solar photoelectric chemical battery, in too Sun irradiation Xia, cathode produces hydrogen, anode produces oxygen, two electrode with wire connection will has current through, that photoelectric chemical battery in too Sun of irradiation Xia while achieved has decomposition water system hydrogen, and system oxygen and obtained power. Scientists around the world attach great importance to this experimental result, considered to be a breakthrough in solar technology. However, photoelectrochemical cells hydrogen production efficiency is very low, only 0.4%, only absorb ultraviolet light from the Sun, and near ultraviolet light, and electrode corrosion-prone, inconsistent performance, it has yet to meet the practical requirements.

(6) solar hydrogen production by catalytic decomposition of water by complexation. Since 1972, scientists found three adjacent pethidine nail of the excited state complexes with electron transfer capacity and charge transfer reaction catalyzed by complex, made use of this process for hydrogen production by photocatalytic decomposition of water. This complex is a catalyst, its role is to absorb light energy, charge separation and charge transfer and Assembly, and through a series of coupled processes, leading to split water into hydrogen and oxygen. Hydrogen production by catalytic decomposition of water by complexation was premature, the research is continuing.

(7) the bio-hydrogen production by photosynthesis. Green algae under anaerobic conditions for more than 40 years ago, after exposure to the Sun can evolve hydrogen; more than 10 years ago, also found that many algae, blue-green algae in an oxygen-free environment to adapt over time, photosynthetic hydrogen under certain conditions. At present, due to the mechanism of photosynthesis and algal hydrogen have so much to learn, algae, hydrogen is inefficient, to achieve engineering there is a considerable gap between the hydrogen. It is estimated that such as algal photosynthesis biohydrogen efficiency to 10%, 9 grams of algae per square metre per day hydrogen molecules, received 50,000 square kilometers of solar, through photosynthetic hydrogen engineering meets United States of all the fuel needs.

How does solar energy convert to heat energy and electricity

How does solar energy convert to heat energy and electricity(I)

Solar energy is radiant energy, have the immediacy, must transform into other forms of energy to use and store. To convert solar energy into different forms of energy require a different energy converters: collector by absorbing solar energy can be converted to thermal energy, photovoltaic solar cells to convert solar energy into electricity, the effect, through photosynthesis, plants can convert solar energy into biomass, and so on. In principle, solar energy can be converted to energy in any form, directly or indirectly, but converting more and eventually lower the efficiency of solar energy conversion.

Solar-thermal energy conversion

Black absorbing surface absorbs solar radiation, can convert solar energy into heat energy, and its absorption capability, but the radiation heat loss, so black absorbing surface is not a perfect solar absorption surface. Selective absorption surfaces with a high ratio of Solar absorptance and lower emission, good capacity of absorption of solar radiation, and radiation heat loss, is more ideal solar absorption surfaces. This absorbing surface by selective absorption material, referred to as selective coating. It was made sometime in the 40 ‘s in 1955 and utility requirements, 70 research into mass production and the selective coating and many new application, has developed hundreds of selective coating.

Solar-power conversion

Electrical energy is a high quality energy, use, transmission and distribution easier. Convert solar energy to electrical energy is important for large-scale use of solar technology, all countries in the world attach great importance to, convert it there are many ways, direct conversion of photoelectric, thermoelectric indirect conversion. Focus on photoelectric conversion devices – solar cells directly.

The world, in 1941, reports of silicon solar cells, developed in 1954 the effectiveness rate of 6% single-crystal silicon solar cell, 1958 applies solar powered satellites. In the 70 ‘s before, due to the low efficiency of the solar cell, the prices are too expensive, is mainly used in space. After 70, solar cell materials, structures and processes have been extensively researched and made more progress in improving efficiency and reducing costs, the ground gradually to expand the scale, but from the large-scale use of solar energy, compared with conventional power generation, the cost remains high.

At present, the laboratory efficiency of solar cells in the world for the highest standard: Mono c-SI 24% (4cm2), SI 18.6% (4cm2), InGaP/GaAs dual junction solar cell 30.28% (AM1), amorphous silicon solar cell 14.5% (the initial), 12.8 (stable), cadmium telluride cells 15.8%, Silicon battery 14.6%, titanium dioxide and organic Nano-cell 10.96%.

Conversion efficiency of solar panels

Solar Panel efficiency

Solar Panel efficiency refers to the conversion of solar panels (solar cell) efficiency in converting sunlight into electricity. Higher conversion efficiency, same power module area can be smaller. MW-level PV power station, set the decreased size, including construction costs, will be reduced. Conversely, if within the same area is covered with solar panels, conversion efficiency, the higher the output power will be bigger and bigger. For plots of land prices and set terms of limited size million-watt class solar power plant business, the conversion efficiency is a very important indicator.

Solar panel consists of several solar cells (power symbol). In solar research and development phases, solar cell efficiency is the focus of attention, and when panels composed of cells (assemblies), due to the current consumption of wiring, efficiency is reduced. Power generation business it is essential that the efficiency of the photovoltaic system as a whole, including the conversion efficiency of solar panels and converted to AC power regulator (PCS) conversion efficiency.

Current solar cells can only convert some of the energy of sunlight into electricity. Now the mainstream is the use of semiconductor materials for solar cells, solar panels from the fires, caused by electron transfer, to generate electricity. Sunlight excitation wavelength depends on the type of semiconductor. Using a variety of compound semiconductor solar theory than the crystalline silicon-type solar cell conversion efficiency higher, because wavelength can be used for power generation and more. Says crystalline silicon-type solar cell conversion efficiency tends to peak, compounds solar conversion efficiency with technological development and there is still a lot of room for improving, this is why.

Technicians currently working on principle of quantum-dot solar power compared to semiconductor solar cells, if in the future this innovative solar cells in use, nearly 40% is possible to achieve a conversion efficiency of high efficiency solar panels.

Conversion efficiency of solar panels

 

Government employs regional authorities to deliver green offer to fuel bad

The federal government has a brand-new ally in the struggle to improve uptake of the foundering eco-friendly offer: regional authorities.

Greg Barker has actually simply revealed the victors of the bid for a share of the £& pound; 88m established apart for their supposed environment-friendly bargain areas plan.

The system will provide 24 regional authorities a bundle of cash to improve power effectiveness in their neighborhoods, provided they access match funding and come up with a convincing street-by-street plan.

The neighborhood authorities to be offered a share of the environment-friendly offer communities system are:

  • London Borough of Haringey
  • Bracknell Forest
  • Eastleigh Borough Council
  • Nuneaton & Bedworth Borough Council
  • London Borough of Harrow
  • Bath & North East Somerset Council

The local authorities will utilize the cash to assist reinforce involvement in green offer actions either by comprising any sort of shortfall in environment-friendly deal and ECO financing or by simply paying for steps themselves.

Most authorities will make use of the cash to deal with personal property owners and real estate associations to set up insulation and double glazing in big blocks of social real estate.

Peterborough city board, where 80 each cent of town hall housing is strong walled, will use the funding, along with £& pound; 8m from ECO and other sources, to install insulation, new central heating boilers and double glazing in 2,000 residences. The houses fall under four areas where there is a high percent of strong wall surface houses and higher degrees of energy destitution.

Council leader, Marco Cerest, mentioned: “This is a great possibility for us to enhance the top quality of housing in Peterborough.I hope landlords come onward and use up the alternatives offered. It makes best feeling for them as they finish up with power happy tenants and effective residences.”

Announcing the bid champions, energy priest, Greg Barker shared:“Properties throughout the nation are leaking hundreds of pounds each year via defective central heating boilers, draughty home windows and not enough insulation. By mounting power saving enhancements we can aid hundreds of difficult pushed customers save electricity and less their costs.This is why we & rsquo; ve quadrupled the eco-friendly offer areas funding, to make sure that regional authorities could assist many more folks take advantage of these improvements.”

But with green deal take up foundering and simply 33 new finance strategies signed in February 2014, is this a lifeline to a struggling scheme, or just a situation of tossing good money after bad?

John Alker, supervisor of policy and interactions at the UK Green Building Council, said:”This brand-new assistance for the eco-friendly offer couldn” t come at a more critical time, following last month” s frustrating data on uptake, and will definitely aid location based delivery of the scheme. Local authorities are a relied on voice and essential to obtaining the message out concerning electricity efficiency. Nonetheless, the federal government could go further by stepping in to lesser rates of interest [ on environment-friendly offer plans] – helping regional authorities to make the eco-friendly deal a much more desirable proposition for the consumer – or by presenting long-term structural rewards, such as variable rates of stamp task.”