Vinasse Concentration and Incineration
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VINASSE FIRED BOILER SLOP FIRED BOILER SPENTWASH FIRED BOILER SLOP INCINERATION VINASSE INCINERATION SPENTWASH INCINERATION DISTILLERY WASTE DISPOSAL DISTILLERY EFFLUENT DISPOSAL DISTILLERY POLLUTION CONTROLTRANSCRIPT
SLOP / VINASSE CONCENTRATION
AND INCINERATION
PRESENT STATUS OF TECHNOLOGY
AVANT-GARDE
Vinasse
Fermented Wash from which the Ethanol and other Volatile
Hydro Carbons have been removed in the Stripper Column
Dark Brown acidic liquid with the pH of 3.5 to 4.5
Contains all Inorganic substance that were present in the
Molasses
BOD and COD Levels at 55,000 and 130,000 respectively
results in Eutrophication if let into water bodies
Solids concentration is expected to be around 14 to 15%
W/Wavantgarde@vsnl.com
The Quantity of Vinasse depends on the alcohol percentage
tolerable in the fermented wash, osmatic pressure tolerance
of yeast and Vinasse recycling (used instead of water for
molasses dilution in fermentation)
With about 8% v/v alcohol content and no vinasse recycling
the quantity is expected to be 10 litres/litre of alcohol
This Quantity could come down to 7.5 to 8 litres per litre of
alcohol if recycling is resorted to
Most of the distillery suppliers today go with vinasse
recycling anywhere between 15 to 25%
Vinasse
Contd..
avantgarde@vsnl.com
Vinasse Disposal
Considered as one of the worst Polluting agent, because of itscolour and high BOD and COD content, various disposal methods
have been attempted
Some of the disposal methods are:
Fert-irrigation
Composting the raw spent wash with filter mud and bagasse ash
Anaerobic digestion with Bio-Gas Generation and Composting
Incineration
Out of the above, Incineration is a clean way of disposalprovided there are no technical issues in the process
If the Incineration results in some useful heat it will be anadded advantage
avantgarde@vsnl.com
The raw Vinasse with 17.5% w/w solids concentration will have
about 6.7% Carbon, 0.645% Hydrogen and has approximate Gross
Calorific Value (GCV) of 525 Kcals/Kg (2195 Kj/Kg)
The low GCV of Vinasse cannot support combustion and even with
a support fuel the Heat Energy in Vinasse could be just used to
evaporate the water in the Vinasse
The Vinasse needs to be concentrated to a higher solids content so
that the combustion could be sustained and some useful heat
energy is derived
It has been found that the Vinasse could be concentrated to 60%
w/w solids without much of difficulty in terms of viscosity and
severe scaling
Vinasse Disposal
Contd..
avantgarde@vsnl.com
Vinasse Concentration
The concentration process needs heat energy for removing
the moisture. A Multiple effect Evaporation system provides
steam economy
Various Evaporator designs have been tried and the one
found to be suitable and economical is a combination of
falling film and forced circulation and flash Evaporation
system
The Vinasse could be concentrated to about 30 to 35% solids
concentration in a falling film evaporator and further
concentration could be done in a forced circulation
evaporator systemavantgarde@vsnl.com
Vinasse Concentration
Contd..
The forced circulation Evaporator, at the cost of additional
electrical power consumption eliminates severe scaling in
the heat exchanger tubes. It employs forced circulation heat
exchanger and flash vessel for Evaporation
In the concentration process the energy economy is very
important as the incineration should yield a net benefit in
terms of energy recovery and expenditure
Todays Distilleries adopt multi pressure distillation principle
in which the various columns operate at different pressures.
Some of the columns operate at vacuum some at higher
pressure and some at atmospheric pressureavantgarde@vsnl.com
This affords the advantage of using the vapours from one
column in the other for the supply of energy. This principle
has also offered the advantage of using the vapours from the
stripper column to be used for concentrating the vinasse in
the first stage
The above called as Integrated Evaporator system uses the
stripper vapours to concentrate the vinasse from a solid
concentration of about 17.5% w/w to 25% w/w
Vinasse Concentration
Contd..
avantgarde@vsnl.com
Integrated Evaporator System
avantgarde@vsnl.com
Independent Vinasse Evaporation System
avantgarde@vsnl.com
Vinasse Concentration Experience
There are a few plants in India concentrating vinasse. TheIntegrated Evaporator concept has just come in and a few plantshave Independent Evaporators for concentration from about 14% to60% w/w
Some of the early designs had faced scaling problems and arenormally cleaned with regular CIP. The new designs with forcedcirculation have very slight scaling. The experience is that theevaporators other than the last body could operate with outcleaning even for 30 days. The last body needs CIP once in 8 to 10days
Chinese have also used the forced circulation evaporatorssuccessfully
Adopting forced circulation system has ensured that there is nosevere problem on account of scaling. Adopting lower temperatureregime has immensely helped
avantgarde@vsnl.com
Concentrated Vinasse Analysis
The following gives the Ultimate Analysis of the Vinasse witha solids concentration of 60% w/w, and the Ash Analysis
Constituent % by Weight
Carbon 22.93%
Hydrogen 2.21%
Oxygen 15.22%
Nitrogen 1.91%
Sulphur 0.63%
Moisture 40%
Mineral Matter 17.11%
Gross Calorific Value 7780 kJ/Kg
Ash Analysis Percent
Silica as SiO2 Nil
Iron oxide as FeO3 2.0
Calcium Oxide as CaO 14.0
Magnesium Oxide as MgO 6.50
Sulphate as SO3 20.0
Phosphate as P2O5 10.0
Potassium oxide as K2O 47.0
Sodium Oxide as Na2O 0.50
Chlorides 6.00avantgarde@vsnl.com
Vinasse Incineration Concerns
There is no issue in Incinerating the Vinasse in a refractory furnace
and letting the gases out after tempering
The concern is only when the Vinasse is to be fired in a Boiler for
Steam Generation
Highly fouling nature of ash due to high alkali (Sodium &Potassium) presence
Severe corrosion potential specifically on Superheaters due tothe presence of Alkalies Chloride and Sulphur
Alkalies, specifically potassium with chlorine forms potassiumchloride and corrodes the Superheater Tubes
Low temperature corrosion due to presence of Chlorine andSulphur
avantgarde@vsnl.com
Vinasse Incineration Boiler Salient Points
Adequate furnace volume to ensure complete combustion of
Vinasse
Adequate furnace heat transfer area to absorb the heat
released in the furnace so as to cool the gases to a lower
temperature of about 500 C at Superheater entry
Proper spacing of tubes for heat absorbing areas to eliminate
bridging of slag
Higher flue gas temperature leaving the boiler to eliminate
low temperature corrosion
Higher economizer inlet feed water temperature to
eliminate low temperature corrosion in economizeravantgarde@vsnl.com
Limit Superheater outlet steam temperature to around 400 C,
to eliminate high temperature corrosion
Use Steam Air Heater
Appropriate spray gun selection for Vinasse feeding to the
boiler
Adequate soot blowers and wall blowers both in numbers and in
locations
Preferably Travelling Grate design for the Boiler
Support fuel for drying and combustion of Vinasse, could be
coal or bagasse or wood chips
Vinasse Incineration Boiler Salient PointsContd..
avantgarde@vsnl.com
Vinasse Incineration Advantages
Foremost is the disposal of Vinasse
The steam generation from Vinasse itself will meet with
about 65% of the Process Plants Energy requirements
Typically for a 60 KLPD plant the Vinasse could generate 13.5
TPH of 42 bar (a) 400 C Steam and using that Steam the
Power Generation could be about 1200 kW
In Indian scenario, the variable cost of steam at 42 bar(a)
with coal firing will be Rs.750 per MT. The Steam generated
from Vinasse will save Rs.7.3 Crores in fuel cost
avantgarde@vsnl.com
The Ash from Vinasse firing is rich in potash and could be
sold as a fertilizer. One of the Indian company has already
started granulating this ash and selling it as a fertilizer. The
Ash Generation will be about 25 to 30 MT per day
A Boiler designed with Vinasse and other supplementary fuel
firing could meet with all the Steam and Power requirements
of the distillery
Vinasse Incineration AdvantagesContd..
avantgarde@vsnl.com
Vinasse Incineration Boiler
- Technology and Experience
Eventhough Vinasse is an obnoxious Pollutant, Parallel can bedrawn with the black liquor in paper plants
Numerous black liquor fired boilers are in operation for ages worldwide
The ill effects of firing the Vinasse in a conventionally designedboiler not understood hitherto have now been understood. Even
the concentration technology with low temperature and forced
circulation have eliminated the severe scaling faced earlier
China and India have been using this technology for a few yearsnow and they have used both FBC and Travelling Grate technology
both technologies work
Coal, Bagasse or Wood Chips could be used as supplementary fuelalong
