About Lithium-Based Battery

There is only one way to charge lithium-based batteries. The so-called 'miracle chargers', which claim to restore and prolong batteries, do not exist for lithium chemistries. Neither does super-fast charging apply. Manufacturers of lithium-ion cells have very strict guidelines in charge procedures and the pack should be charged as per the manufacturers "typical" charge technique.

Lithium-ion is a very clean system and does not need priming as nickel-based batteries do. The 1st charge is no different to the 5th or the 50th charge. Stickers instructing to charge the battery for 8 hours or more for the first time may be a leftover from the nickel battery days.

Most cells are charged to 4.20 volt with a tolerance of +/?0.05V/cell. Charging only to 4.10V reduced the capacity by 10% but provides a longer service life. Newer cell are capable of delivering a good cycle count with a charge to 4.20 volts per cell. Figure 1 shows the voltage and current signature as the lithium-ion cell passes through the charge stages.

 

• Preparing new lithium-ion for use

Unlike nickel and lead-based batteries, a new lithium-ion pack does not need cycling through charging and discharging. Priming will make little difference because the maximum capacity of lithium-ion is available right from the beginning. Neither does a full discharge improve the capacity of a faded pack. However, a full discharge/charge will reset the digital circuit of a 'smart' battery to improve the state-of-charge estimation.

 

• What happens if a battery is inadvertently overcharged?

Lithium-ion is designed to operate safely within their normal operating voltage but become unstable if charged to higher voltages. When charging above 4.30V, the cell causes plating of metallic lithium on the anode; the cathode material becomes an oxidizing agent, loses stability and releases oxygen. Overcharging causes the cell to heat up. If left unattended, the cell could vent with flame.

 

• Much attention is focused to avoid over-charging and over-discharging.

Commercial lithium ion packs contain a protection circuits that limit the charge voltage to 4.30V/cell, 0.10 volts higher than the voltage threshold of the charger. Temperature sensing disconnects the charge if the cell temperature approaches 90°C (194°F), and a mechanical pressure switch on many cells permanently interrupt the current path if a safe pressure threshold is exceeded. Exceptions are made on some spinel (manganese) packs containing one or two small cells.

 

• Extreme low voltage must also be prevented.

The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible.

There are several safeguards to prevent excessive discharge. The equipment protects the battery by cutting off when the cell reaches 2.7 to 3.0V/cell. Battery manufacturers ship the batteries with a 40% charge to allow some self-discharge during storage. Advanced batteries contain a wake-up feature in which the protection circuit only starts to draw current after the battery has been activated with a brief charge. This allows prolonged storage.

 

• Lithium Ion (Li-Ion)

Lithium Ion batteries are very different. You should not deliberately discharge a Li-Ion cell. In fact, if you were to manage to run one flat, it would probably be damaged. There is electronics inside each Li-Ion battery to protect it from such abuse, but don't take the risk!

 

To keep your Li-Ion battery in good shape, simply charge it overnight before it runs down. If a full battery at all times matters to you, you can top it up whenever you like, but you'll probably get a longer service life from it if you only recharge it when it is getting a bit low.

 

• Storage

Batteries of any type don't like to be left discharged. In general, if you have a spare battery, it is probably best to use it alternately with its partner.

• Declining years

Li-Ion batteries can fail suddenly, possibly because the electronics inside it have gone wrong, but in general they simply fade away. Because the capacity falls gradually over the charge cycle life, when to replace it is a matter of when the charge capacity is no longer sufficient for your needs. Never try to revitalise a Li-Ion battery in any way, or expose it to excessive heat: the very high power density of Li-Ion makes such actions very dangerous.

 

Summary :

• Never discharge your battery fully as safety circuits can fail when a low charge is left in your battery
• As a rule try to charge your battery when it reaches approximately 20%
• As soon as a Li-ion battery is created from the factory, the life of it decreases ever so slowly so buying a spare and not using it as much does not see much better life
• If you need to store a Li-ion battery that is not used, charge or discharge it to approximately 40% and store in a cold environment such as a fridge to prolong battery life
• Li-ion do not need priming and do not have a memory effect as did Nickel Cadium Batteries did
• Li-ion batteries prefer a partial discharge instead of a full discharge

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Operator Dictionary (D)

DAMPER
Usually a flap or shutter to control air flow in a furnace (may be in the supply and/or the flue ducting).

DEACTIVATION
Reduction in catalyst activity by poisoning or coating of catalyst particles by contaminants, or by a change in the physical structure of the catalyst particles.


DEADWEIGHT
The amount of cargo, stores and fuel which a vessel carries when loaded to the appropriate draught allowed by law. The difference between deadweight and displacement is the actual weight of the vessel.

DEARATOR
Device for the steam stripping of 0₂ and other gases from boiler feed water.

DEBTORS
Accounts receivable.

DECOMPOSITION
The breaking up of compounds into smaller chemical forms through the application of heat, change in other physical conditions, or introduction of other chemical bodies.


DEFERRED TAXATION
Provision for tax payable in the future, but deferred in the current year because of timing differences between the Company's accounts and the accounts required by the Inland Revenue Department.

DEHYDRATION
The removal of water from crude oil, from gas produced in association with oil, or from gas from gas‑condensate wells.

DEHYDROCYCLISATION
Any process involving both dehydrogenation and cyclisation reactions.

DEHYDROGENATION
A reaction process in which hydrogen atoms are eliminated from a molecule.

DEIONIZED WATER
Water that has had all the free ions removed by ion‑exchange, also called demineralised water.

DEISOLATION
The opposite of isolation i.e. To energise a piece of equipment.

DEMISTER
Any device used to stop passage of liquid droplets e.g. a demister section in a vacuum column is to stop the asphaltenes from the residue getting into the waxy distillate.

DEMULSIFIER
An additive used to prevent the formation of an emulsion ‑ applicable in crude/water emulsions in desalter.

DEMURRAGE
Amount payable to ship owner for failure to load or discharge ship within time allowed.

DENITRIFICATION
Removal of nitrogen compounds on feedstock by hydrogenation. N₂ + 3H₂ = 2NH₃.

DENSE BED LOADING
Catalyst loading system of "raining" the catalyst onto the bed which achieves a higher loaded density than "sock" loading.

DEOXYGENATION
Removal of oxygen on feedstock by hydrogenation. 0₂ + 2H₂ = 2H₂0.


DESALTING
A process to remove inorganic salts and other impurities from crude oil by mixing with water followed by settling in an electrostatic field.

DESULPHURISATION
The removal of sulphur or sulphur compounds from a charge stock.


DESUPERHEATER
Equipment used to reduce the temperature of superheated steam.

DETERGENCY
The ability of a substance to clean and to wash away undesirable substance. Detergents may be either oil‑soluble or water‑soluble. Soap and synthetic detergents help to wet, disperse, and de-flocculate solid particles. Oil‑soluble detergents are used in motor oils to disperse, loosen, and remove carbon, dirt, etc. from interior surfaces of internal‑combustion engines.

DETERGENT OIL
A lubricating oil possessing special sludge‑dispersing properties for use in internal‑combustion engines. These properties are usually conferred on the oil by the incorporation of special additives. Detergent oils hold sludge particles in suspension and thus promote engine cleanliness.

DETONATION
Detonation or knocking is the sharp metallic sound emitting from the cylinders of spark‑ignition engines under certain conditions. It occurs when conditions in a cylinder are such that self‑ignition of an unburnt mixture of fuel and air takes place. It reduces power output.

DEW POINT (at a given pressure)
The temperature at which a vapour, contained in a closed vessel under the given pressure, will form a first drop of liquid on the subtraction of heat. Further cooling of the vapour at its dew point results in condensation of part or all of the vapour as liquid. The dew point of a normal gasoline is approximately the same as the temperature at which 70% by volume distils over in the ASTM‑distillation test. The dew point of a pure compound is the same as its boiling point.

DEWAXING
The process of removing paraffin wax from lubricating oils.

DIESEL ENGINE
As internal‑combustion engine in which air drawn in by the suction stroke is so highly compressed that the heat generated ignites the fuel, which is automatically sprayed into the cylinder under high pressure.

DIESEL FUEL
A general term covering oils used as fuel in diesel and other compression ignition engines.

DIESEL INDEX
A measure of the ignition quality of a diesel fuel; the index is calculated from a formula involving the gravity of the fuel and its aniline point (API gravity times the aniline point (determining by ASTM D611‑47T) divided by 100).

DIFLUOROETHANE
A catalyst promoter used on the Hydrocracker.

DILUENT
A liquid used to dilute or thin out another liquid.

DIPPING
A process for measuring the height of a liquid in a storage tank. This is usually done by lowering a weighted graduated steel tape through the tank roof and noting the level at which the oil surface cuts the tape when the weight gently touches the tank bottom (see Ullage).

DISTILLATE
The liquid obtained by condensing the vapour given off by a boiling liquid. Also the top product taken off a fractionating column; and in its broadest sense: any fraction other than the bottom product of the fractionator.

DISTILLATION
(fractional) A fractionation process based on the difference in boiling point of the various constituents of the mixture to be fractionated. It is carried out by evaporation and condensation in contact with reflux. When applied to the separation of gasoline, kerosene, etc., from a crude oil, to leave a residual fuel oil or asphaltic bitumen, the process is frequently called topping. Distillation is normally carried out in such a way as to avoid decomposition (cracking); in the case of the higher boiling distillates, such as long residue, this is accomplished by carrying out the distillation under vacuum (which requires a lower temperature).

DISTILLATION CURVE
Curve made by plotting the percentage of gasoline (or other petroleum product) distilled versus the temperature.

DISTILLATION LOSS
The difference, in a laboratory distillation, between the volume of liquid originally introduced into the distilling flask and the sum of the residue and the condensate recovered.

DISTRIBUTOR (LIQUID/GAS)
A device for distributing a 2 phase flow correctly within a vessel, i.e. encouraging separation. DISULPHIDE A compound containing a ‑S‑S‑ linkage. Such compounds are colourless liquids completely miscible with hydrocarbons and insoluble in water. The lower members, when pure, possess a nauseating sweet odour which is particularly clinging and penetrating. Although disulphides are normal constituents of the lighter distillates, they are also formed as a result of the oxidation of mercaptans. Sour distillates become sweetened in this way.

DIVIDEND COVER
Net profit after tax and before extraordinary items Dividend for year.

DIVIDEND YIELD
Market Price of Shares (cents).
Dividend Paid (cents).

DOCTOR SOLUTION A
solution (sodium plumbite) made from lead oxide and sodium hydroxide, used to treat gasoline or other light petroleum distillates to remove mercaptan sulphur. The "doctor test" is used for the detection of sulphur compounds in light petroleum distillates which react with sodium plumbite.

DOCTOR TREATMENT
A process of sweetening sour gasoline’s ‑ by conversion of the mercaptans ‑ by means of a solution of lead oxide in caustic soda, together with sulphur.

DOLPHIN 
Separate pile in jetty system ‑ used for mooring.

DOWNCOMER
A means of conveying liquid from one tray to the next below in a trayed column.

DOWNSTREAM 
Towards the later end of the process e.g. final blending, product tankage. In the business sense ‑ Marketing of finished products, filling stations etc.

DRAW OFF
A connection which allows liquid to flow from the bottom of a vessel or to remove the contents from a draw off tray.

DRY GAS
Natural gas which does not contain liquid hydrocarbons at storage pressure. Also often used for a petroleum gas consisting of no other compounds than inert gases (e.g. hydrogen, nitrogen, etc) and the light hydrocarbons methane, ethane, ethene, propane, propene (sometimes also: hydrogen sulphide).

DUAL PURPOSE KEROSENE
An export grade Kero that meets both premium and Avtur specifications.
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Coal Gasification Could Fuel Clean Coal

There is a growing consensus that increased demand for electricity will cement coal's place in the energy portfolio for years to come. In fact, more than half of the electricity produced in the United States comes from coal. With demand for electricity expected to double by 2050 and renewable resources still years away from offsetting increased demand, it is clear -- coal is here to stay.

But can 'dirty' coal be used cleanly? The answer may be a resounding yes if gasification becomes common place, researchers said February 15 at the 2008 Annual Meeting of the American Association for the Advancement of Science in Boston.

"Coal gasification offers one of the most versatile and clean ways to convert coal into electricity, hydrogen and other valuable energy products," said George Muntean, staff scientist at the Department of Energy's Pacific Northwest National Laboratory.

"Gasification provides significant economic and environmental benefits to conventional coal power plants," Muntean said. Rather than burning coal directly, gasification breaks down coal into its basic chemical constituents using high temperature and pressure. Because of this, carbon dioxide can be captured from a gas stream far more easily than from the smokestacks of a conventional coal plant.

"If we plan to use our domestic supply of coal to produce energy, and do so in a way that does not intensify atmospheric CO2 concentrations, gasification is critical," Muntean said. "It has the potential to enable carbon capture and sequestration technologies and play an important role in securing domestic sources of transportation fuels."

Many experts predict that coal gasification will be at the heart of clean coal technology if current lifespan and economic challenges are addressed. One significant challenge is the historically short lifespan of refractories, which are used to line and protect the inside of a gasifier. Currently, refractories have a lifespan of 12 to 16 months. The relining of a gasifier costs approximately $1 million and requires three to six weeks of downtime.

"Gasification happens in an extreme environment so the lifespan of refractories is historically low," said S.K. Sundaram, PNNL staff scientist. "Refractory lifespan must be increased before we can realize the promise of clean coal."

During the symposium, S.K Sundaram highlighted two advanced gasifier models developed at PNNL that provide a scientific understanding on when and why refractories fail at such high rates. The data collected from these models could enable advanced or alternative gasification technologies to be produced. Use of these models could extend refractory lifespans by 3 years.

"Advances in modeling will help us better understand some of the key challenges associated with coal gasification -- refractory durability and lifespan," Sundaram said. "This will help reduce the capital costs of operating a coal gasifier."

During the symposium, researchers at PNNL also highlighted advances in millimeter wave technology that could be used for real-time measurement of critical parameters (temperature, slag viscosity, refractory corrosion) inside a gasifier. The millimeter wave technology, developed at PNNL, has been used for a number of different applications, from airport security to custom fit clothing. Although in the early stages of development for this application, the technology shows promise to increase the efficiency and safety of coal gasifiers.

"Advances in gasification will help us meet demand for clean energy worldwide," Sundaram said. "Science and technology are paving the way for cleaner coal for future generations."


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What is Hot Tapping ?

A few week ago we've have problem in our heat exchanger, there was a leakeage in the tube side.  We realize that the consequences of a shutdown would not be practicable. So the management decide to use the hot tapping methode to reduced the leakage.

 

Hot tapping, or under-pressure drilling,  is a method of making a connection to existing pipelines or tanks while that existing system is under pressure.  This method employs a drilling or tapping machine, a full-ported valve and a pressure-containing fitting to the existing pressurised system.  The end result a new branch connection abstracted from the original pipe while the line is still operational.

 

A necessary element in most hot-tap connections is the full-ported valve, which can become a control valve for the new connection, and allows the drilling machine to be removed after the cutting operation. Gate valves and other full-ported valves with flanges and screwed connections; typically include 150lb through 900lb ANSI ratings.

 

PHL purchases its machinery from leading international suppliers of hop tap equipment and therefore has access to the latest developments in this fast-moving engineering process. PHL is therefore able to put a wider range of solutions together, testing the boundaries, whilst maintaining good practice and adhering to our stringent safety codes.

 

The overall process is completed without any leakage or interruption to the flow of liquid. It is possible to perform a hot tap on pipes from 1" to 48" with pressure ratings up to 1480 psi and temperatures up to 700 degrees Fahrenheit.

The types of pipes that this method can be applied to is almost unlimited:

• Cast iron
  
• Ductile iron
  
• Non ferrous metal
  
• Mild steel
  
• Plastic
  
• Reinforced concrete

 

 

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