Gasification Technology for Rolling Mills_ppt

7/15/2019 Gasification Technology for Rolling Mills_ppt

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GASIFICATION TECHNOLOGY FOR

SUBSTITUTION OF FURNACE OIL IN REHEATING

FURNACES OF ROLLING MILLS

B. V. RAVI KUMAR

Director, Cosmo Powertech Pvt. Ltd.Near J ain Public School, Devpuri, Dhamtari Road,Raipur – 492 015, Tel: 0771- 5011262, Fax: 0771-5013016

Email: [email protected]



Cosmo Powertech Pvt. Ltd. : Activities

R & D and commercialization of coal and biomass gasifiers

Commercial utilisation of gasifiers for

- Substitution of furnace oil in steel rolling mills, steel wire units, aluminiummelting / heating, refractories, etc.

- Small scale power generation

Contract R & D in Iron & Steel sector

Process & energy related consultancy

Work in progress on pyrolysis of coal & biomass



What is Gasification?

GASIFIER(Partial oxidation process)

Solid Fuel

Air or

oxygen ,

steam

Gaseous Fuel

Ash or slag

Solid fuel converted into clean combustible gas by partial oxidationprocess

Gasifiers are available, which can accept woody biomass, rice husk,agricultural residues and coal as input fuel

Efficiency of conversion varies in the range 60-85%, depending upontype of gasifier design and fuel

Composition of Gas: CO: 10-20%, H2: 10-20%, Hydrocarbons: 1-6%,

CO2:6-12%, N2: 45-55% (for air gasification)

Calorific Value of Gas: 1000-1300 kCal / Nm3 (for air gasification)



Where Can the Gasifier be Used?

Fuel Gas

Cooling/

Cleaning

Diesel

Engine Gen.Power

Gasifier

Diesel

Fuel Gas

Cooling/

CleaningGas Engine

Generator Power

Gasifier

Fuel Gas

Oil Fired

EquipmentHeat

Gasifier

Gas for

Chemical and Metallurgical

Processes

Fuel Gas

Gas

ConditioningGasifier



Relevance of Gasification Technology

Solid fuel, when converted into gas, becomes compatible for substitution of liquid fuels in most of the applications – INCLUDING ROLLING MILLREHEATING FURNACES

Gas generated from coal or biomass would be much cheaper thanpetroleum based oil in most parts of India

On an average, 4 kg of solid biomass / coal can give gas equivalent to 1 litreof petroleum fuel. The price of 4 kg solid fuel may vary between Rs. 3.00-6.00 whereas 1 litre of diesel costs Rs. 20.00-22.00 and 1 litre of FO costsRs. 10.00-13.00

Gas combustion is less polluting as compared to direct solid fuel burning oreven furnace oil combustion

Financial savings to individual users, cleaner environment to society, foreignexchange savings to the Nation



Types of Gasifiers

Moving bed gasifiers

Entrained flow gasifiers

Fluidized bed gasifiers

Moving Bed Gasifiers

Fuel bed moves gradually downwards counter-current or co-current to theflow of gases

Fuel required to be in lumps, fines not suitable

Suitable for both coal & biomass Gasifying medium could be air or oxygen

Ash disposal could be dry or in slag form

Flexible to changes in capacity utilisation, fuel type and fuel size

Examples: Lurgi Dry Ash & BGL Slagging Gasifiers



Entrained Flow Gasifiers

Pulverized fuel flows co-currently with gases

Fuel required to be pulverized form

Suitable for coal only as it is difficult to pulverize biomass

Gasifying medium is usually oxygen

Operate at very high temperatures, > 1000 C

Ash disposal is usually in slag form

Examples: Shell, Destec and Texaco Gasifiers



Fluidized Bed Gasifiers

Fuel suspended in gasifying medium (air), air & solid fuel particles together

behave like a fluid

Fuel required to be in small particles (usually less than 5 mm)

Suitable for both coal and biomass

Gasifying medium is usually air Reactor temperatures are generally maintained less than 1000 C

Ash disposal is usually in dry form

Examples: HTW , MBEL Gasifiers



COSMOMULTIFUEL UPDRAFT

GASIFIERS

Developed and commercialized

for substi tution of petroleum

fuels in industrial furnaces



Cosmo Multi-Fuel Gasifiers : Features

Convert coal, wood or briquettesof agro residues into producergas

Coal of any grade up to 35% ash

content acceptable

Fuel size: 20-200 mm forbiomass and 25-75 mm for coal

No change in gasifier required

while switching the grade of coalor from coal to wood orbriquettes

Substitute FO, LDO, Diesel or

LPG in furnaces, kilns, hot airgenerators, thermic fluid heatersetc.

Suitable for 25-1000 litres/hour of liquid fuel substitution

Producer gas generated from thegasifier has a calorific value of 1100-1300 kcal/Nm3 and



Suitable for 25-1000 litres

/hour of liquid fuelsubstitution

75-85% conversionefficiency

Cosmo Updraft Gasifiershave fuel flexibility, operatewith higher efficiency andgive higher flametemperatures as compared

to downdraft gasifiers

Smoke less than FO,pollution decreases

Substantial savings-paybacknormally less than one year

2.2-4.2 kg. Coal (dependingupon grade or 3.5-4.0 kg drywood can substitute 1 litre of

FO/LDO/Diesel

Flexibility of operation withoil retained



Oxidation Zone

In the oxidation zone, just above the grate, oxygen in air reacts with carbon:

C + O2 ------> CO2 + heat

Also, the steam, which enters the reactor along with air, reacts with

carbon to produce CO & H2 :

C + H2O + heatÅ-----------ÆCO + H2

Temperatures in the oxidation zone are of the order of 1000-1200 0C.

Reduction Zone

CO2, coming from oxidation zone, reacts at the hot carbon surface:

C + CO2+ heatÅ--------Æ 2CO

Steam (H2O), which escapes un-reacted from the oxidation zone, reacts

here with carbon:

C + H2O + heatÅ--------Æ CO + H2

Reduction zone temperatures are in the range 600-1100 0C.

Pyrolysis Zone

Here, at temperatures between 150-600 0C, volatile matter of fuel is liberated. Fixed carbontravels downwards in the reactor and takes part in reduction and oxidation reactions. Volatilematter, which is a mixture of several hydrocarbons, travels upwards, mixed with gas and comesout of the gasifier as part of producer gas.

Drying Zone

Moisture in the fuel is liberated.

Updraft Gasification



SCHEMATIC OF CUA-SERIES UPDRAFT GASIFIER



Gasifiers for Furnace Oil Substitution in Individual

Roll ing Mill Furnaces

Most rolling mills are in the range of 5 to 15 tons / hour output capacity

Furnace oil substitution requirement is presumed to be in the range of 200 to 750 litres / hour

For such capacities, air blown, moving bed gasifiers are likely to be mostsuitable

For rolling mills in the regions away from coal mines, the option of biomass may be more viable

Entire furnace oil substitution possible

To take care of contingencies, oil burners are also retained

Installation of a gasifier of appropriate capacity as near to the furnace aspossible

Insulated gas piping of suitable size from gasifier to the furnace

Suitable combustion air system with minor modifications in piping

No major changes in the original equipment (i.e. furnace, kiln, etc.)

required

No effect on the original process



Solid Fuel to Furnace Oil Conversion Ratios

Calorific Value of Solid Fuel

(kcal/kg)

Quantity of Solid Fuel Required

to Substitute 1 litre FO

(kg)

3000

3500

4000

4500

5000

5500

6000

6500

4.5

3.9

3.4

3.1

2.7

2.5

2.3

2.1



Economics of Gasifier Installation

The landed price of solid fuel, in equivalent energy terms (say in Rs. per 1000kcal) varies greatly over different parts of the country. Some indicative examples

are in the following Table:

Fuel / Location CalorificValue

(kcal/kg)

LandedPrice

(Rs./ton)

Price inRs./1000

kcal

1500

3500

1200

0.405

0.636

0.343

3700

5500

3500

D-grade coal in Central India

B-grade coal in North India

Biomass in South India



Assumptions for Calculation of Payback Period

Capacity of gasifier : 5 million kcal/hour (equivalent to 500litres / hour oil)

Investment (excluding coal handling) : Rs. 9.00 million (Rs. 90 lacs)

Furnace oil substituted : 400 litres / hour

Price of furnace oil : Rs. 13.00 / litre

Operating hours : 12 hours / day

Interest : 9 % flat

Payback Period for Different Values of Solid Fuel Price

Solid Fuel Price(Rs./1000 kcal)

0.25 0.30 0.35 .0.40 0.45 0.50 0.55 0.60 0.65 0.70

2.00 2.561.651.401.211.070.960.870.790.73Payback Period

(years)



Environmental Aspects

Gas burns with cleaner flame : lower dust emissions (evident frominvisible smoke from chimney

Biomass has negligible sulphur and even Indian coal has lower sulphurcompared to furnace oil for equivalent energy output : lower SO2

emissions

CO is a result of incomplete combustion, better mixing of gas & airpossible, with good combustion control lower CO is expected

When biomass is used as fuel, net CO2 additions to atmosphere arezero



Centralized Gasification Facility for a Cluster of

Rolling Mills

Gasification activity can be de-linked from individual mills

Individual mills can draw gas from distributed gas grid

Gas generation facility could come up as a co-operative venture or asseparate business entity

Gasification Technology (entrained flow or moving bed or fluidized flow)needs to be made depending upon the envisaged size of plant, demandvariation over the day, characteristics of the fuel available,etc.

A detailed techno-economic study would be required to ascertain variousinfluencing parameters



Thermal Applications of Gasifiers

Heating of Steel in Rolling Mill Rolling Mill Furnace

Tunnel Kiln for Stoneware PipesCO2

Manufacturing



Site : M/S R. R. Ispat Ltd., Urla Industrial Area,

Raipur (Chattisgarh), India

Capacity & type of : 5 million kcal/hourgasifier installed Multi-fuel updraft

Month & year of : March, 2000commissioning

Fuel used in : D-grade coal (about 30% ash)gasifier

Fuel substi tuted : Fuel oil

Application : Steel reheating for hot rolling

Operating duration : 24 hours / day

M/S R. R. Ispat Ltd. is a steel rolling mill producing 6 to 32 mm diameter rounds and TMT bars. The production capacity of the mill is 10-15 tons /hour. Before installation

of the gasifier, fuel oil was being utilised to heat

steel billets / ingots up to rolling temperature(11500C). The maximum fuel oil consumptionwas about 500 litres / hour. Now, fuel oil hasbeen completely substituted by producer gasgenerated from coal. The maximum coal

consumption (D-grade coal) is about 2000 kg /hour. The fuel cost of heating steel has comedown by 40-45%.



Site : M/S Unique Structures & Towers Ltd.,

Urla Industrial Area, Raipur (Chattisgarh), India

Capacity & type of : 1.25 million kcal/hougasifier installed Multi-fuel updraft

Month & year of : October, 2001

commissioning

Fuel used in gasifier : Wood or rice husk

Fuel substituted : Fuel oil

Application : Steel reheatingfor hot rolling

Operating duration : 8-12 hours / day



The gasifier has been installed here under an R&D project, carried out in collaboration

with Indian Institute of Technology, Mumbai and sponsored by Ministry of Non-conventional Energy Sources, Govt. of India.

M/S Unique Structures & Towers Ltd. produces a range of products, which includeangles, channels, rounds & flats in 16 – 150 mm size. The production capacity of the

plant is 5-8 tons / hour steel and it normally operates on 8 hours / day basis. Thefurnace is fired 2-4 hours before start of rolling. Originally, the reheating furnace of themill was fired by with fuel. The average fuel oil consumption was about 280 litres /hour. The gasifier substitutes about 50% of the original oil consumption. To substitute140-150 litres /hour of fuel oil, 500-600 kg / hour of wood or 700-750 kg / hour of rice

husk is being consumed. The reduction in fuel costs is 20-30% depending upon therelative prices of oil & biomass.



Site : M/S Nahta Metals & Air Products,Urla Industrial Area,


Capacity & type of gasifier installed : 0.50 million kcal/hour

Multi-fuel updraft

Month & year of commissioning : May, 2002Fuel used in gasifier : wood


Application : CO2 manufacturing


M/S Nahta Metals & Air Products manufacture carbon dioxide (CO2) for the soft-drinks industry and for inert gas welding applications. The unit was manufacturing180-200 kg / hour of CO2 by burning 65-75 litres / hour of fuel oil. Now, fuel oil has

been replaced by producer gas generated from wood. After installation of thegasifier, about 200-210 kg / hour of wood is being consumed to produce the sameamount of CO2. The savings achieved in fuel costs are more than 50%.



Site : M/S Sunil Steel Wires, Bhanpuri ,


Capacity & type of : 0.50 million kcal/hourgasifier installed Multi-fuel updraft

Month & year of : May, 2002commissioning

Fuel used in gasifier : D-grade coal (about 30%

ash) or wood


Application : Annealing & galvanizing of steel wires


M/S Sunil Steel Wires produce galvanized steel wires of various gauges. They have2 production lines of for continuous annealing and galvanizing operations. Originally

fuel oil was being used for these operations. Theconsumption of fuel oil was 0-80 litres / hour. Afterinstallation of the gasifier, fuel oil has been replacedby producer gas generated from 200-250 kg / hour of either wood or D-grade coal. Switching from wood to

coal or vice-versa is done without any interruption inthe operation. The savings in fuel costs are morethan 50%.



Site : Mahakoshal Potteries, Katni (M. P.), India


Multi-fuel updraft

Month & year of commissioning : November, 1999

Fuel used in gasifier : B-grade coal

(about 20% ash)


Application : Baking of refractory bricks


M/S Mahakoshal Potteries produce refractory bricks. The baking of bricks (1150-12500C) is done in a tunnel kiln, which was originally fired by fuel oil. The gasifierwas installed to substitute 50 % of the original fuel oil consumption of 50 litres /hour. The gasifier is now substituting 25-30 litres /hour of fuel oil by producer gasgenerated from 65-80 kg /hour of B-grade coal. The savings in fuel costs are of

the order of 20%.



Site : M/S Perfect Stoneware Pipes,

Gwarighat Road, Jabalpur (M. P.), India

Capacity & type of gasif ier installed : 0.50 million kcal/hourWood - Downdraft

Month & year of commissioning : May, 1996Fuel used in gasifier : wood


Application : Baking of stoneware pipes


M/S Perfect Stoneware Pipes produce stoneware pipes for sanitary piping. These pipes are baked in tunnel kiln at temperatures up to 11000C. The Kiln was

fired by about 80 litres / hour of fuel oil. The gasifier consumes 160-180 kg / hourof wood and generates producer gas to substitute about 45-55 litres / hour of fueloil. The savings in total fuel costs are in the range of 20-30%.



Site : M/S Kesari Metals Ltd., Urla Industrial Area,



Wood - Downdraft

Month & year of commissioning : September, 1998

Fuel used in gasifier : wood

Fuel subst ituted : Fuel oil

Application : Heating of aluminum ingots

Operating duration : 8-10 hours / day

M/S Kesari Metals Ltd. produce aluminum extrusions of various shapes & types. Forextruding, aluminum ingots are heated up to a temperature of 4500C, which was doneby firing 10-12 litres / hour of fuel oil. After installation of the gasifier, the fuel oil hasbeen substituted by producer gas generated from 30-35 kg / hour wood. The savingsin the fuel costs are more than 50%.



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www.cosmopowertech.com

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Gasification Technology for Rolling Mills_ppt