Training manual on Best Operating Practices

for

Howrah foundry cluster

Prepared for

Swiss Agency for Development and Cooperation (SDC)

About the manual

Foundry is one of the most energy intensive sub-sectors in MSME sector in India. It is one of the important sub-sectors in overall economy of the country. Howrah is one of the largest foundry clusters in India. There are about 320 foundries located in Howrah cluster with a total production of 750,000 tonne of castings per year. The typical energy costs in total production costs in a foundry unit vary from 15-25%, which is quite significant.

Though adoption of energy efficient technologies such as Divided Blast Cupola (DBC) system would help in improving energy performance of foundries, it is essential that the system must be operated efficiently and various operating parameters must be maintained at optimum levels. However, the technical skills of factory floor personnel play an underlined critical role in sustaining energy efficiency in foundries.

The existing technologies can yield significant energy savings at a relatively lower cost, if the technical skills of plant operators and supervisors are upgraded through training in best operating practices (BOP). Structured training or availability of suitable guidance/ manual is absent which further aggravates the poor performance of foundries. Experiences show that 3-5% of energy saving is possible through adoption of BOP which have marginal or no investments. With this background, TERI had initiated training programs for foundry personnel in Howrah cluster for identifying various best operating practices and train them in their adoption.

This manual on “Best Operating Practices” provides various simple measures along with potential energy and monetary savings that can be adopted by foundry personnel which would help them in saving energy and improve the overall performance.

This study was conducted as part of the project “Scaling-up Energy Efficiency in Small Enterprises (EESE)” being undertaken by TERI with the support of the Swiss Agency for Development and Cooperation (SDC).

Raw material storage

Before After

Prevents wetting of raw material from rain and storm water 0.1% increase in coke consumption per 1% increase in moisture in coke

Cost benefit Cost: Rs 0.25-0.5 lakh, Savings: 0.1-0.5% coke, Payback: 12 – 24 months

Storage in open area Store under shed

Rain water logging Shed

Bed coke size

Before After

Leads to high quantity of initial chill metal 100 kg chill metal corresponds to 13 kg coke consumption

Cost benefit Cost: Negligible, Savings: 0.2-0.5% coke, Payback: Immediate

Large coke used for bed preparation Recommended bed coke size 3-6”

Coke size > 10” Coke size < 6”

Bulk density of coke

Before After

Coke consumption and bed height optimized Estimate bulk density using a 2' high dummy well with cupola ID

Cost benefit Cost: Negligible, Savings: 3 – 5 % bed coke (~one Jhuri), Payback: Immediate

Bed coke quantity not estimated Coke for bed and charge calculated

using bulk density

Dummy well

Limestone size

Before After

Effective de-slagging and reduced lining erosion Reduction in refractory consumption

Cost benefit De-slagging cost: 30% higher, Savings: 20 – 40% refractory, Payback: Immediate

Large size ≥ 3” Recommended size 1-2”

Limestone quality

Before After

Better de-slagging Lower possibility of tap hole and tyuere blockage

Cost benefit Cost: 30% higher, Savings: 20 – 40% refractory, Payback: Immediate

CaO content ˂ 35% CaO content recommended > 45%

CaO = 33% CaO = 43%

Scrap and foundry return size

Before After

Sub-optimal charge pre-heat leading to additional coke consumption Chances of bridging high

Cost benefit Cost: Rs 700/heat, Savings: 2-3% coke (~one Jhuri), Payback: NA

Size larger than safe limit Restrict metallics size ≤ ⅓ of furnace ID

Size > 50% of ID

Size < ⅓ of ID

Shot-blasting of foundry return

Before After

Reduction in energy consumption De-slagging chemical consumption reduced

Cost benefit Cost: Rs 1.5 lakh, Savings: 1 – 2%, Payback: 06 – 12 months

Returns not free from moulding sand Minimize sand in foundry returns

3 – 5 % sand content 1 – 2 % sand content

Bundling of scrap

Before After

Cost benefit Cost: Rs 3.5 lakh, Savings: 1.5% electricity, Payback: 12 months

Loose or bigger size bundle scrap Restrict size to ⅓ of crucible ID

Reduction in specific energy consumption of induction furnace Enhancement of production efficiency

Lining repair

Before After

Cost benefit Cost: Negligible, Savings: 20 – 50% refractory, Payback: Immediate

Refractory and patching mass improper Use IS8/6 and proper patching mass

Refractory requirement per melting campaign reduces by about 35% Avoid pre-mature relining of cupola

Weighment of raw material

Before After

Cost benefit Cost: Rs 0.1 – 0.2 lakh, Savings: 2-3% coke (~one Jhuri), Payback: Immediate

Raw materials not weighed Weigh and record charges

Improved performance and trouble-shooting Help in better operation of cupola

Stack filling

Before After

Cost benefit Cost: Negligible, Savings: ~1% coke, Payback: Immediate

Charge height in stack not maintained Stack to be always full

Pre-heating of charge sub-optimal, loss of heat in flue gases Increased erosion of lining

Irregular split coke quantity

Before After

Cost benefit Cost: Negligible, Savings: 2 – 5% coke, Payback: Immediate

Quantity subjectively fixed Quantity for 200 mm height in cupola

Melt rate and temperature of metal will be affected Possibly will result in oxidation and chilling of metal

Pressure gauge

Before After

Cost benefit Cost: Rs 3000 – 5000, Savings: Proper air distribution, Payback: Immediate

Improper pressure gauge and location Install gauge in accessible location

Ensures proper air pressure and easy monitoring Use glycerin filled dial pressure gauge calibrated in MMWC

Air leakage in wind box

Before After

Cost benefit Cost: Negligible, Savings: 1 – 2 kWh/tonne melt, Payback: Immediate

Wind box damaged by wear and tear Periodic inspection to arrest leakage

Lower volume and drop in pressure Excess air generated by blower leading to higher power consumption

Hole in wind box

Air leakage from tuyere cover

Before After

Cost benefit Cost: Negligible, Savings: 1 – 3% coke, Payback: Immediate

Lack of sealing in tuyeres Ensure proper seal of tuyere covers

Reduced melt rate and metal temperature Inadequate blast pressure and volume

Leakage from tuyere

Sealing

Slag quality

Before After

Cost benefit Cost: Linked with other BOPs, Savings: Reduced iron loss and coke consumption

Slag thick and blackish in color Easy flowing and moss-green in color

High oxidation due to: thin rusty scrap, hard blowing, uneven charge distribution, high percentage of steel or bridging (Iron oxide in slag < 8%)

Ladle lining

Before After

Result in temperature drop leading to higher coke consumption Use refractory and fireclay in 3:1 ratio for preparing lining material

Cost benefit Cost: Rs 1000-2000/ladle, Savings: 0.5-1% coke, Payback: Immediate

Surface temperature >350° C

Refractory lining

Ladle lining was done improperly Use ladle with proper lining

Radiation loss in induction furnace

Before After

Reduced radiation loss and improved production efficiency Improvement in work-place environment

Cost benefit Cost: Rs 2 – 3 lakh, Savings: 3-5% input energy, Payback: 09 – 12 months

No lid used for entire batch cycle Use lid during melting & superheating

Automation in charging system

Before After

Reduced specific energy consumption Enhanced production efficiency

Cost benefit Cost: Rs 3 – 6 lakh, Savings: 3-5% input energy, Payback: 09 – 12 months

Raw material charged manually Use mechanical charging system

V-belt for motors

Before After

Energy saving by improved transmission Increased life of belt

Cost benefit Cost: Rs 0.1 – 0.2 lakh, Savings: 1 – 3 % input electricity, Payback: 06 – 12 months

Flat V-belts used Use cogged V-belts

Flat belt

Cogged

Blower motor

Before After

Every re-winding reduces efficiency of motor by 2 – 4% Ensure proper input voltage to avoid burn-out

Cost benefit Cost: Rs 1.5 – 2.0 lakh, Savings: 3 – 8 % input electricity, Payback: 18 – 36 months

Use of re-winded motors Motors re-winding max twice

Standard motor IE2 motor

Bottom door probes

Before After

Bottom probe failure may lead to stoppage and production loss Fire hazard and safety

Cost benefit Cost: Marginal, Savings: Safety, Payback: NA

Corroded, undersized Place two probes of 2" diameter

Placed straight Not straight

Locking of fettling door

Before After

Ensure proper safety during cupola operation

Cost benefit Cost: Marginal, Savings: Safety, Payback: NA

Secured with single clamp Make two tier locking arrangement

Single clamp

About TERI A dynamic and flexible not-for-profit organization with a global vision and a local focus, TERI (The Energy and Resources Institute)

is deeply committed to every aspect of sustainable development. From providing environment-friendly solutions to rural energy

problems to tackling issues of global climate change across many continents and advancing solutions to growing urban transport

and air pollution problems, TERI’s activities range from formulating local and national level strategies to suggesting global

solutions to critical energy and environmental issues. The Industrial Energy Efficiency Division of TERI works closely with both

large industries and energy intensive Micro Small and Medium Enterprises (MSMEs) to improve their energy and environmental performance.

About SDC SDC (Swiss Agency for Development and Cooperation) has been working in India since 1961. In 1991, SDC established a Global

Environment Programme to support developing countries in implementing measures aimed at protecting the global environment.

In pursuance of this goal, SDC India, in collaboration with Indian institutions such as TERI, conducted a study of the small-scale industry sector in India to identify areas in which to introduce technologies that would yield greater energy savings and reduce

greenhouse gas emissions. SDC strives to find ways by which the MSME sector can meet the challenges of the new era by means of

improved technology, increased productivity and competitiveness, and measures aimed at improving the socio-economic conditions of the workforce.