Sugar Plant High Pressure on

MODERN TRENDS IN SUGAR PLANT HIGH PRESSURE CO-GENERATION

www.avantgarde-india.com AVANT-GARDE

Avant-Garde - 22 Years of Sugar Experience

• Early 1990: Avant-Garde established by a group of Technocrats

• An ISO 9001:2008 Organisation

• Areas of Specialization:

Consultancy for Captive and Cogeneration Power plants with Renewable and Fossil fuels

Energy Conservation and Energy Audits

Consultancy for Sugar Plants and Ethanol Distilleries

Solar PV and Solar Thermal Power plants

Core Competence

Captive power plant Sugar plants

Cogeneration plant Distillery Plants

Steam Generator design and Engineering

Water and Waste Water treatment plants

Waste Heat Recovery systems Industrial Effluent Treatment plants

Mini Hydro Electric power plants Process piping

Combined cycle power plants Equipment design

Solar Thermal & Solar PV power plants Procurement & Site supervision

Energy Audit Third Party Inspection services

Engineering software development Residual Life Assessment

Our Association with Sugar Mills

• Designing Bagasse and Multi-fuel Fired Boilers - Around 80 Boilers are in Operation, Revamping

• Designing Co-generation Plants for wide capacity range of Sugar Mills

• Providing Sugar Plant Consultancy Services including Sugar Plant Automation

• Providing Ethanol Plant Consultancy Services

• Energy Audit for Sugar Mills

Cogeneration Experience

• Pioneered Bagasse Cogeneration in India and Commissioned the first project (18.68 MW) in November 1994 - Market Share in India about 75%

• Commissioned 74 Projects, including a 34.2 MW Project in Kenya, with the aggregate generation capacity of 1550 MW

• Implementing 38 Projects, including a 80 MW Project in Pakistan, with the aggregate generation capacity of 957 MW

• Completed Feasibility Reports for 62 Projects aggregating to 1150 MWMarket Share

75%

Commissioned

74 Projects

Implementing

38+ Projects

Avant-Garde Sugar Cogeneration Experience

with Cycle parameter

S.NoCycle

Parametersbar(a) / °C

Commissioned

Under Implementati

on

1 45 / 440 14 5

2 67 / 485 16 3

3 87 / 515 27 6

4 110 / 535 16 22

5 125 / 545 1 2

Total 74 38

Avant-Garde’s Bagasse & Coal Fired Installations

• Out of the 74 Projects commissioned so far, 57 are designed with Bagasse and Coal firing capability and 27 are operating with coal. All the Sixteen (16), 110 bar installations are operating with Bagasse and Coal

• The maximum size of the unit under operation is a 36 MW plant in Maharashtra. The maximum capacity of the plant is 44 MW to be commissioned in Maharashtra. Both units will be in full fledged operation by the 3rd quarter of this year. Both units are for bagasse and coal

• Under execution is 2 x 40MW units designed for bagasse and coal for JDW Sugars Limited in Pakistan

What is Co-Generation ?

• It is the Co-incident generation of Thermal and Electrical energy, from the same fuel source, where both forms of energy are put to productive use.

*This is generally in the form of Low Pressure Steam

Fuel Cogeneration Plant

Electrical Power

Inhouse Consumption

Export to Grid

Useful Heat Energy*

Industries Where Cogeneration is Possible

• Any Industry needing low pressure process steam could be a candidate for Cogeneration

• Typical Industries

Sugar Textile Paper Chemical and Petro Chemical Metals

• Most of the Cogeneration applications are in Topping Cycle mode

Sugar Plant’s by-products Utilization

• Under the present Economic scenario, the Economic viability of the Sugar mills are quite uncertain

• The situation could some extent be redeemed by value addition through by products utilization

• Molasses and Bagasse are two by products of Sugar manufacturing which could be utilized profitably

Value Addition through Byproducts

Sugar Plant’s Energy Requirements

• Sugar plant needs both Thermal and Electrical energy

• Thermal energy is needed to concentrate the sugar juice for crystallization, It is supplied by low pressure steam, typically at 2.5 bar(a) and the steam is used efficiently in multiple effect evaporators. (typically 36% steam on cane)

• Electrical energy is needed for driving the mills, pumps and other machinery. (typically for all electrical drive mill 24 KW/MT of cane crushed)

Cogeneration in Sugar Mills

• Cogeneration is not new to the Sugar industry, every Sugar mill is designed with cogeneration of Thermal and Electrical energy

• However, conventionally the power generation was restricted to in house consumption

• The boiler steam parameters were adjusted to generate just adequate power while giving the required process steam

• Cogeneration under present day context is additional power generation for export to grid by adopting higher boiler steam parameters

Boiler Parameters for Sugar Mill Co-Generation

• Gradual increase in the Operating Pressure of bagasse fired boilers with the advent of energy conservation and cogeneration

• With low pressure boilers and steam turbine drives there was always mismatch resulting in inefficiency and use of supplementary fuels like wood or oil

11

14

21

32

42

67

80

110

125

135

bar

How Higher Pressure Power Cycles Help?

• Every 100 kg of bagasse will produce the following steam and power for various power cycles in a pass out turbine with 2.5 bar as the exhaust pressure. Feed water inlet to the boiler at 105°C.

Steam Cycle Parameters Steam Production Power Generation ata / °C (KGS) with BP of 2.5 bar(KW)

21 / 340 250 22.7332 / 380 243 28.6042 / 400 240 31.3045 / 440 233 32.8067 / 485 227 37.8087 / 515 224 40.10110 / 540 220 44.10125/545 220 45.54


• Every 100 kg of bagasse will produce the following steam and power for various power cycles in a condensing turbine with 0.1 bar exhaust pressure. feed water inlet to the boiler at 105°C.

Steam Cycle Parameters Steam Production Power Generation

ata / °C (KGS) with BP of 0.1 bar(KW)

21 / 340 250 42.532 / 380 243 51.442 / 400 240 53.845 / 440 233 55.567 / 485 227 60.187 / 515 224 64.6110 / 540 220 66.5125/545 220 68.6


• With higher pressure energy extraction from steam is high with out the exhaust steam moisture levels getting into unacceptable levels

• Higher boiler pressure means higher saturation temperatures

• With higher saturation temperatures and with an economical economizer approach, the design permits heating the feed water to a higher temperature before it enters the boiler

• Adopting regenerative heaters to increase the feed water temperature improves the cycle efficiency

• With the increase in the turbine inlet pressure and depending on the turbine size more heaters could be introduced to increase the feed water temperature to higher values

The comparison was made as part of the feasibility study for a 3500 TCD Sugar Mill

Comparison of various cycle Parameters

Comparison of various cycle Parameters

Efficiency – Where are we vis-à-vis utilities?

A typical coal fired power plant of 40 MW capacity

Boiler steam parameters of 110 bar(a) and 540°C

No reheat

Deaerator and two stages of hp feed water heating

Final feed water temperature of 210°C

Water cooled condenser with the vacuum of 0.09 bar(a)

Coal HHV of 6500 kcals/kg and boiler efficiency of 84% on HHVHHV

31.76%

LHV30.32

%

Efficiency – Where are we vis-à-vis Utilities?

Contemporary Thermal Power plant Efficiencies

Efficiencies typically for 500 / 660 MW plant Source: NTPC, India

• A 40 MW plant efficiency as seen above at 31.76% (Gross on HHV) is 5.84% less compared to the base efficiency of 37.6% of the coal fired utility thermal power plant

• The difference goes up to 8.14% considering the modern super critical plants

• The possible reasons Boiler outlet steam pressure of 170 bar against 110 bar Boiler efficiency difference between a PF and Travelling

grate type The reheat will increase the efficiency by about 1.5% The utility plant employs almost 7 stages of feed water

heating as against three in the 40 mw plant Bigger turbine with less losses. turbine cycle heat rate of

1900 Kcals/kWhr as against 2260 Kcals/kWhr

Efficiency – Where are we vis-à-vis utilities?

Cogeneration Efficiency - Where are we vis-à-vis Utilities?

• While the Electrical energy was the only output from the 40 MW plant, a cogeneration plant gives both thermal and electrical energy as output

• Electric eff. (EFFe) = Y/X

• As ‘Z’ increases, EFFe comes down and that is what happens to the electric efficiency under cogeneration mode. Typically for a sugar mill cogeneration EFFe comes to around 21% (net based on LHV)

• (Z+Y)/X – is called the combined heat and power (CHP) efficiency

• Cogeneration Efficiency is the maximum if the total output from the plant is considered

if ‘Z’ is zero EFFe approaches the efficiency of the 40 MW power plant

Operation with Sugar Mill

• The Cogeneration plant should operate in synchronize with the Sugar mill

• Basically the sugar mill operations are fluctuating both in terms of energy demand and bagasse generation. The Cogeneration plant should be designed to take care of these

• As the process steam supplies are generally large, the high temperature condensate should be taken back to the Cogeneration plant

• Possibility of contamination of the condensate and consequent large make up to be taken care of in plant design

Feed Water Management – Crucial while operating in sync with Sugar Mill

• Maintaining the quality of return exhaust condensate from sugar mill is important. No vapor condensate will be used as boiler feed water

• Permissible levels of Silica, Iron, Copper and other minerals are lower at higher pressures

• Vaporous carry over of Silica increases with pressure and poses serious scaling problem in turbines

• Make up will be only DM water. Membrane based treatment plant preferred but could be decided based on raw water analysis

Operation with Sugar Mill

Bagasse - The Primary Fuel

• The major advantage of sugar mill cogeneration is that the fuel is generated in house

• Bagasse is the residue of cane after juice extraction and because of the process of extraction, it is loaded with 50% moisture

• Bagasse is an excellent fuel with 40% volatiles, 8.5% fixed carbon and 1.5% ash with the GCV of 9205 KJ/KG

• Bagasse availability depends on cane variety, climate and irrigation and is generally around 30% of the cane (with 50% moisture)

Alternate/Supplementary Fuel

• The Sugar mills crush only for a limited number of days in a year and hence the bagasse availability is limited

• By proper sizing and optimization some bagasse could be saved in the season for the off-season operation of the power plant

• However year round operation of power plant will call for alternate fuels. these alternate fuels could be used as supplementary fuel in case of exigency in season

• Coal and Bio-mass are the major alternate fuels

Technology Options for Cogeneration

Gasification Route:

• Promising future technology. A lot of work is going on to fine tune the technology and make it a commercially viable option

• Not an advisable option as of now

Combustion Route:

• Well established route, wherein the fuel is combusted in a boiler to generate steam to drive the turbine

• The boiler to be designed considering the primary and alternate/supplementary fuel characteristics

Major Equipment

• Boiler system – generally of the travelling grate stoker fired

• Turbogenerator system – extraction pass out type or extraction condensing type

• Water Treatment plant – additionally makes up the losses on the return condensate

• Fuel (bagasse and supplementary fuel like coal) and Ash handling systems

• Distributed Control System (DCS)

• HV and EHV Electrical system

Technology Options for the Boiler

Pulverized Fuel Firing

• Not a viable option as pulverization of as milled bagasse is not possible. co-firing of bagasse with coal is possible, but has limitations

Ciculating Fluidized Bed Combustion (CFBC)

• Low ash content in bagasse is a limitation. Can be fired along with coal with the coal percentage being higher at 60 to 70%

Atmospheric Fluidized Bed Combustion (AFBC)

• Because of the lightness of bagasse not possible to burn in AFBC boilers

Spreader Stoker Travelling Grate

• Better suited technology to fire bagasse and coal or any other bio-mass. unfortunately comes as the lowest ranking in terms of boiler efficiency

Technology Options for Turbogenerator

Pass Out (Backpressure)

Extraction Condensing

All the Steam supplied will be exhausted to process. There will be no condenser. Power generation is incidental to process steam flow. Turbine can not operate if there is no process steam requirement.

Part of the input steam is extracted at the desired pressure through ports in turbine. the balance steam goes to the condenser. the turbine could be designed for condensing the entire input steam.

Sugar Mill Cogeneration Plant Design Basis• Adopt energy conservation measures in the sugar mill to reduce

the process steam consumption and the power consumption

• Select an extraction condensing turbogenerator designed for both season and off-season operation

• The cogen plant size should be based on the process steam requirements and the minimum steam requirements for condenser and feed water heaters

• Downsizing the plant will enable saving of bagasse for a few days of operation in off-season. use of cane trash or other biomass as supplementary fuel to bagasse or coal should be envisaged in the design

• The coal usage should be minimized considering the low efficiency of operation compared to utilities

• Use extensive feed water heating to improve the efficiency

• Use extensive Electrical protection and controls to safeguard the machine and to prevent plant tripping during grid failure

Current State of the Technology

• Combustion route with travelling grate boiler and extraction condensing turbine

• The plants are being designed for multi fuel firing (mostly bagasse and coal) to run the plants year round

• The steam parameters has steadily increased and the prevalent is 125 bar(a) and 545°C

• As the plant sizes are in the range of 15 to 40 MW, considering the cost, these parameters will stay for quite sometime

• Will probably await gasification to further improve the efficiency

Avant-Garde Design

• 135 bar(a) 545°C cycle is under engineering

• Studies are in progress for introducing steam drying of

bagasse with extraction steam from Cogeneration

turbine

• Configuration of Cogeneration plant with reheat cycle

under engineering with development of suitable

turbines with manufacturers

Sugar mill Co-Generation – Indian Scenario

• The first project with a capacity of 18.68 MW was commissioned in 1994

• Could probably have a total installed capacity of around 2000 MW, with another 1500 MW could be under implementation

• A large number of the projects implemented are with steam parameters of 110 bar(a) and 540°C few units of 125 bar (a) 540°C have been implemented

• Majority of the plant sizes are in the range of 20 to 40 MW and most of them are designed with bagasse and coal firing

• Large number of projects are being designed with air cooled condensers

• Because of the shortage in grid capacity, these projects are getting good encouragement

A few of Our Recently Completed Cogeneration Projects

• Mumias Sugar Company Limited, Kenya

• Rajshree Sugars Limited, Tamil Nadu, India

• Hemarus Technologies Limited, Maharashtra, India

• Sunil HiTech Limited, Maharashtra, India

• Bannari Amman Sugars Limited, Tamil Nadu, India

Mumias Sugar Company Limited, Kenya

Location Mumias, Kenya

Boiler170 TPH, 87 bar(g), 515°C, Bagasse

TG capacity 34.2 MW

Gross Power Generation

Crushing SeasonOff-Crop

34.2 MW28 MW

Power Export


27.1 MW24.8 MW

Project Cost US$ 55 Million

Commissioning Date May 2009

Rajshree Sugars Limited, Tamil Nadu, India

Location Tamil Nadu, India

Boiler

110 TPH, 110 bar(g),540°C, Bagasse & Coal

TG capacity 20 MW



20 MW20 MW

Power Export


14.15 MW17.81 MW


Commissioning Date October 2008

Hemarus Technologies Limited, Maharastra, India

Location Kolhapur, India

Boiler

110 TPH, 110 bar(g),540°C, Bagasse & Coal

TG capacity 20 MW



20 MW20 MW

Power Export


14.5 MW17.5 MW


Commissioning Date

December 2010

Sunil Hitech Limited, Maharashtra, India

Location Gangakhed, India

Boiler

150 TPH, 110 bar(g), 540°C, Bagasse & Coal

TG capacity 30 MW



28 MW30 MW

Power Export


20.9 MW26.8 MW


Commissioning Date

December 2009

Bannari Amman Sugars Limited, Tamil Nadu, India

Location Thirukkoilur, India

Boiler

130 TPH, 125 bar(g), 545°C, Bagasse & Coal

TG capacity 25 MW



25 MW25 MW

Power Export


19 MW22 MW


Commissioning Date May 2011

Sugar Plant Gallery

34.2 MW PLANT AT MUMIAS SUGAR COMPANY INKENYA OPERATING SINCE MAY 2009

34.2 MW Cogeneration Plant at Mumias Sugar Company, Kenya

Commissioned in April 2009

AVANT-GARDE


34.2 MW COGEN PLANT AT MUMIAS SUGAR COMPANY, KENYA

34.2 MW TG at Mumias Sugar Company, Kenya

AVANT-GARDE


34.2 MW COGEN PLANT AT MUMIAS SUGAR COMPANY, KENYA

34.2 MW TG AT MUMIAS, KENYA

170 TPH, 87 BAR(A), 515 DEG.C BOILER AT MUMIAS

Plant Control Room at Mumias Sugar Company, Kenya

AVANT-GARDE

17 MW Cogeneration Plant Commissioned in 2001

AVANT-GARDE

16 MW, 67 bar 485°C Cogeneration PlantCommissioned in 1999

AVANT-GARDE

Cooling Tower and Water Treatment Plant

AVANT-GARDE

50

23 MW Cogeneration Plant with ACC Commissioned in 2006

AVANT-GARDE

28.8 MW Plant with ACC Commissioned in 2009

AVANT-GARDE

30 MW Direct Coupled TG Commissioned in 1997

AVANT-GARDE

20 MW Cogeneration PlantCommissioned in 2003

AVANT-GARDE

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