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 CONTROL

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  • 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