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 Uptil
now Knowell Cells which are huge in size, have been used
for Hydrogen generation by Water Electrolysis process.
These Cells require large space and consume 6.5 KWH for
each Cubic Meter Hydrogen generation. These are open type
Cells and often require overhauling to remove carbonate
formed due to adsorption of atmospheric CO2. Also these
require huge quantity of electrolyte. Now MECPRO offers
Bipolar cells, which are very compact, require small quantity
of electrolyte and low power consumption of 4.5 KWH per
M3 of hydrogen produced.
 Bipolar
Cells |
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The cell is of
circular shape for uniform distance between Anode
& Cathode. |
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The asbestos diaphragm is fixed
on solid frames with bolting, which keeps the generated
gases separate and maintain uniform purity. |
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The frames, Centre Electrodes,
End Electrodes, End Frames are fully machined from
selected Steel and Nickel plated to have uniform
pressure on each face and gasket. Thus, the iron
in electrolyte and leakage is fully controlled. |
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The installation of Electrolyte
separation tanks, Gas coolers and Gas washing tanks
are arranged in such a manner that the cell can
be attended without dismantling the complete plant.
The cell can be easily installed in a room of 15
feet height. |
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The (+)ve (Anode) and (-)ve
(Cathode) connections are provided on top of cell
to have minimum length of bus bars and maximum safety. |
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The filter provided will remove
any fine fibres of asbestos, dust, rust and carbonate
which cause resistance to electricity and reduce
efficiency. |
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The Anode and Cathode electrodes
are designed and fabricated from 2 mm thick CRCA
steel to have minimum over voltage of gases and
uniform distribution of electrolyte and electricity. |
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The plants are supplied with
base frames and insulators ready to install without
foundation. |
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The M-1000 and M-2000 filter
press type cells can be easily installed in parallel
and series with 2000 Amps Knowell Cells. The combination
will produce more gas using the rectifier already
in use. The disconnected Knowell Cells can be kept
as spare for replacement of damaged Knowell Cells.
Thus, Knowell Cells can be replaced most economically
by MECPRO's Bipolar Cells. |
| Electrolyte |
The specific conductivity of Potassium Hydroxide (KOH)
is higher than that of Sodium Hydroxide up to 100oC and
is less corrosive. We use electrolyte of 28% concentration
having 1.288 Specific Gravity at 20oC made from KOH of
followings specifications:
Carbonate(K2CO3)
|
<1.0% |
| Chloride (CI) |
<0.002% |
| Sulphate (SO4) |
<0.003% |
| Iron (Fe) |
<0.005% |
| Feed
Water |
 The performance and long life of electrolyser depends
on the quality of feed water. As only Hydrogen and Oxygen
together with some water vapour escape from the electrolyser,
each impurity introduced with the feed water will accumulate
in electrolyte i.e. chloride, sulphate and iron. The former
will have harmful effect on Nickel metal, which leads
to heavy corrosion and the latter will cause impure Oxygen
gas. The most suitable and economical method for production
of pure feed water is by ION Exchanger (DM water). For
immediate detection of impurities in feed water its specific
conductivity shall be monitored and should not exceed
2x10 6 ohm/cm.
| Purity
of Gases |
MECPRO's is electrolyser produces Oxygen and Hydrogen
of following purities: H2 : 99.8%+0.2% O2 : 99.5%+0.5%
For producing ultra high purity Hydrogen from these cells,
we provide a Deoxo unit and a Dryer unit. Purified gas
contains less than 1 ppm oxygen impurity and dew point
is (-)70oC.
| Control
System |
We provide a control panel and instrumentation system
with alarm and tripping functions for ensuring safe and
unattended operation. Also an online gas analyser continuously
indicates Hydrogen purity.
| Deoxo
System |
We can provide Deoxo purification and Dryer units for
Oxygen as well as Hydrogen gases. A catalytic Deoxo purifier
removes oxygen while a twin tower, Molecular Sieves dryer
removes moisture and produces Hydrogen gas of following
purity:
Oxygen
|
1
ppm (max) |
| Hydrogen |
99.9999% |
| Dew point |
Upto
(-)70oC |
| Pressure
of Gas |
Both gases are produced at around 250 mm WG pressure and
taken to low pressure floating type Gas Holders. If Oxygen
recovery is not required, it is vented through pressure
balancing tank to atmosphere. For producing Hydrogen gas
at higher pressure, we provide a Diaphragm type or a Reciprocating
type Compressor which can deliver Hydrogen gas upto pressure
of 150 kg/cm2.
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Oil & Fats
Industry. |
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Hydrogenation of Edible Oils
and Fatty Acids. |
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Metallurgical Industry. |
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Reducing protective atmosphere
for heat treatment of metals. |
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Chemical Industry. |
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Hydrogenation process
and ammonia synthesis. |
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Electronic Industry. |
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Protective atmosphere
for manufacture of electronic components. |
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Glass Industry. |
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Protective atmosphere
for casting float glass on molten metal bath. |
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Industrial Gas
Companies. |
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Purification of
argon, oxygen etc. |
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Meteorological
Stations. |
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Observation balloon
filling. |
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Meteorological
Stations. |
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Protective gas
and reducing agent. |
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| Bi-Polar
Cells |
Knowll
Cells |
| Adjust
cooling water flow once a shift |
Cooling
and heating as and when required |
| Adjust distilled
water flow once a shift |
Adjust water
level every hour |
| Tempeprature
measured continuously |
Not possible
to measure temperature of each cell continuously |
| No leakage
of gases |
Check gas
leakage every hour Gas losses 5% per cell average
(188x5)=0.9 M3/hr in 15 Nm3/hr plan |
| Lye losses
very little @5 ltr/month |
Makeup lye
losses every week (20 ltr/month/cell=20x18=360 Ltrs/month
in 15 Nm3/hr plan |
| Lye in closed
condition and hence no fumes |
Blow-off
of gases and electrolyte in case of over pressure
and low level of electrolyte. |
| No air pollution
and no fire hazards |
Minor leakage
of gases cannot be detected which causes caustic
atmosphere in cell room and surrounding areas. |
| Lye concentration
in cell is uniform throughout the unit |
Lye concentration
is too low on top & too high near electrode. |
| No formation
of carbonate as electrolyte is in closed cell. |
The electrolyte
is open to atmosphere. It absorbs carbon dioxide
and Sodium carbonate is formed which is a resistance
to electricity |
| No damage
to plating if pure distilled water is used as makeup
water (free from chlorine and sulphate) |
Damage to
plating because of over heating, short circuit in
cells, deposition of carbonate and solid caustic |
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