Business Model For Adapting Energy Efficient Moulding Technology in Foundries

Foundry – being an Energy Intensive Industry is known to all. Several studies have been done by Institutions like CII, UNIDO, BEE and also several individuals, at 57th IFC Dr.M.Arasu, L.Rogers Jeffrey from PSG presented a detailed study on the energy consumption in Foundries, a comprehensive guide to energy efficiency in Canadian foundries was also made.

Lot of studies and work has been done for the major energy consumer of the foundry industry i.e. melting shop and lot of work has been done which is on an average 70%, but varies on the extent of mechanization and type of melting facility.

As the say, once the main parameter has been taken care of in the Foundry Business Model, we should focus on the 2nd highest consumer in the foundry – Moulding Process.

The study is more focused on Green Sand Moulding process – the most widely used process for casting production, probably more than 70-80 % of the castings produced in Grey/SG Iron are produced by green sand moulding process.

Mould making may consume as much as 20% of all energy in the foundry, depending on the technology used.The prevalent green sand mould making consists of sand and clay receiving, conveying, preparation, delivery to the mould area, mould handling, shakeout, reclamation, reconditioning and more conveying.*

The moulding process would again be comprising of two distinct processes:

a.?????? Mould making

b.????? Sand Management

Creating a Business Model

To create a business model dealing in nos and figures, let us first put together the elements of energy which go into the process.

A. Mould Making

Principally the moulding process can be divided into 3 major categories from the perspective of Energy Efficiency Evaluation:

1. Simultaneous Jolt Squeeze Moulding Technology working on Compressed Air (JSQ)
2. High Pressure Moulding Technology working on combination of Compressed Air and Hydraulic Energy (HPML)
3. High Pressure Moulding Technology working on Hydraulic Energy only (FM)

In terms of basic mechanical engineering, the efficiency of power transmission through compressed air has been considered the poorest, even if very popular and useful, to as low as 30%, which some manufacturers have been able to improve to a bit more. The specific energy consumption of compressed air as stated by “Kaeser” in their case study is 1.4 to 1.6 kWh/cfm at 7 bar pressure.

In hydraulics the specific energy consumption or transmission is between 85% to 90%, though such equivalent calculation on specific consumption has not been calculated.

Rhino Machines produces FM working on only Hydraulic Energy Transmission, delivering 10 kg/cm2 specific squeeze pressure while the JSQ – a very popular and widely used technology produces between 1.5 to 2.5 kg/cm2 i.e 5 to 6 times lower than the High Pressure Machines.

Based on studies and data collected over last 14 years Rhino has tabulated the comparison in the figure below

The energy consumption and the commercial impact is tabulated considering all the Operating cost factors, and a comparison between the two processes has been shown.

When comparing with JSQ – both the high pressure routes have also a distinct advantage of weight saving as a result of the 5 to 6 times higher squeezing force applied with the right pre-compaction.

We had made a study on the actual energy consumption for a typical mould size for JSQ machine in actual production, and that of FM series in our factory with 1 hour of running.

The energy consumed per hour for a 600x600 mm box size in FM was 0.19 kWh/mould while that for JSQ – ARPA 300 machine was about 0.3 kWh/mould (we have not factored the compressor efficiency here).

This would impact a metal saving of about 2% from weight saving, about 0.5% from rejection and the contribution from 2.5% of additional saleable castings. A typical Savings Balance Sheet of JSQ v/s FM installation is as under. The table takes into account the energy factor, weight saving as well as the manpower, investment, maintenance costs to give a net saving per year. This balance sheet was prepared in explains the business model of investing in High Pressure Moulding working with ONLY hydraulic energy to realize comprehensive energy advantage, with the saving over 3 years.

In a recent article by V Satyanarayana (VP – DISA) (Oct 2017 MMR Foundry Review Magazine) who produce both JSQ & the Compressed Air-Hyd Combination High Pressure moulding machines, they have estimated a weight saving of 5 to 8% as compared to ARPA Machine…the business case becomes even more strong considering this estimated saving.

However, the energy efficiency business model does not end here. We also need to evaluate the energy installed and consumed in the process of high pressure moulding and handling as a comprehensive comparison. The innovative thinking of Renzo Cappelletto – Fondarc France – the brain behind the development of MultiflexFM? in India with Rhino Machines, has taken energy efficiency to the next level.

In the fully hydraulic process as stated above FM series consumes about 0.19 kWh/mould for a box size of 600x600 x 150 mm with multipiston. The equivalent compressed air – hydraulic combination have still higher energy consumptions. The comparison below compares the business model with a Flaskless High Pressure Moulding line working with Compressed Air-Hydraulic Combination.

In the mould handling again, Renzo Cappelletto has demonstrated at GIFA 2015, and Rhino has partially implemented the solution in India of RoboFlex and RoboFM? - using servo drives of robot, reducing the movements, consumed energy in handling of the moulds before and after preparation. It is expected to reduce the energy consumed by nearly 40 to 50% directly, and increase productivity by nearly 15 -20% with better uptime and lower maintenance of Industrial Foundry Duty Robots. In the year 2018, data on this innovative solution will also be generated and shared.

Rhino Machines has already optimized the energy for even the conventional mould handling system with turnover, closing machines and the total energy for a foundry capable of producing 1000 TPM – the total power of moulding and mould handling is just 60 kW! ?

B. Green Sand Handling & Processing

?The second and equally important energy consumer for the moulding technology is sand plant - where the sand handling, sand cooling and sand preparation are managed. It is an integral part of any moulding process, and in present context of green sand moulding process. The figure below gives an overall picture of the entire Green Sand Process – Circulation System.

We have tried to capture the energy consumed in different activities of Sand System as below.? We can divide the energy consumption into Handling, Mixing, Cooling & Dust Collection. Typical comparison of the Conventional Sand Plant with Bucket Elevator Design and the one with rEcoflex? design installed power is shown below in the two for 40 t/hr and 10 t/hr plants.

The Basis of this Energy Saving is derived from addressing the root cause analysis (Why Why …) done by Rhino team.

• Bucket Elevators create turbulence, have higher travel velocity which results into more dust generation and therefore huge amount of dust collection energy
• Bucket Elevators consume more energy for the travel of same height and length, as they move with a higher speed – about 75 to 90 m/sec v/s the belt working at 30 m/sec or max 60 m/sec, and the fact that they also carry the additional load of buckets – the combined effect increases the power need.
• The cooling and mixing is a common machine – RMC or MaxCool – the innovation of Renzo Cappelletto about more than 10 years ago eliminated additional equipment and the energy used for mixing is used partially for cooling.
• The belt conveyor design allows natural cooling by recirculation with the same installed energy, improving the utilisation of the dust collection at polygonal sieve.
• Another energy saving not accounted is the illumination of the sand plant with lower height, lower foot print and lower pit area. This has not been quantified right now.

The Business Case of Energy Efficient Sand Management in the Moulding Process is given below for a 40 MT/hr Sand Plant.

A recent case study publication on energy saving in Sand Plant was given by Brakes India in Foundry Magazine in Nov 2017 wherein the power consumption for the sand and dust collection was stated as 10 kWh/MT which they reduced to 9 kWh/MT, of which 75% of the energy was of the dust collector. They stated that the dust collection energy is fixed and they could reduce only the mixing energy.

This once again reiterates our conviction to WORK ON THE ROOT CAUSE and eliminate bucket elevators (which also have a high maintenance cost and break down %age), and move to the rEcoFlex? design sand plant.

The Business Case Summary?

We have tabulated a combined business advantage particularly for MSME’s – foundries operating from 15 MT per month to 1500 MT per month as below:

Disclaimer: The views and findings are conducted by Rhino Machines, without any prejudice to any brand or make or manufacturer. Errors and Omissions maybe pointed out with relevant data.

References:

https://www.pjms.zim.pcz.pl/PDF/PJMS4/IMPORTANCE%20OF%20ENERGY%20MANAGEMENT%20IN%20FOUNDRIES.pdf? Seweryn Jar?a – Polish Journal

https://www.foundryinfo-india.org/tech_section/pdf/57ifctp12.pdf - Energy consumption studies in cast iron foundries at 57th IFC, Dr.M.Arasu, L.Rogers Jeffrey, PSG, Coimbatore

Guide to Energy Efficiency - Opportunity in Canadian Foundries by CIPEC

https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/oee/pdf/cipec/ieep/newscentre/foundry/Foundry_eng.pdf? -