PSI Blog

The Root of Sustainable Metals Production - 7 Ways to Go Green and Improve Operational Efficiency

19 Aug 2021 - Energy, Industry 4.0, Production, Sustainability, Technology

A Mighty Tree Starts with a Seed – Let’s Plant it Together! ©00one/iStock; edited by PSI Metals
A Mighty Tree Starts with a Seed – Let’s Plant it Together! ©00one/iStock; edited by PSI Metals

When solving problems and realizing potential, it is more effective to dig at the roots instead of just hacking at the leaves – treating the cause rather than the symptoms, so to speak. When it comes to sustainable metal production, the question often arises as to whether manufacturers should invest on becoming more green or on improving their operational efficiency which are both the root of sustainable metals production. Sounds like a dilemma, but it is not! Discover 7 ways in which even small, but forward-thinking investments in planning and scheduling solutions can result in significant environmental improvements that go hand-in-hand with greater plant efficiency.

While the ultimate solution for emissions reduction involves very large investments and big structural changes to production equipment and the energy sources utilized in a metals plant, there are numerous short term actions. These actions, although limited in their potential, still bring significant environmental improvements, which are coupled with efficiency gains in the plant.

Consider a steel making plant that produces one million ton per year, consuming approximately 2.5 MWh per ton produced.

A reduction of 2% on energy consumption, easily achievable with specialized optimization tools, means less 50,000 MWh per year utilized.

Using Germany as an example, where the CO2/MWh ratio is 485Kg/MWh in average, that translates to less 24,500 tons of CO2 emitted per year, or the equivalent of removing 6,000 cars of the streets.

A mighty tree starts with a seed – so how can the Production Management System and the Planning Suite in particular support waste reduction and energy consumption in your steel plant?

Let's take a look at the following 7 optimization opportunities!

Opportunity #1: Reducing Energy for Heating with Melt Shop Scheduling Tool

Let’s start from the melt shop. Here, we know that the heat temperature and the time spent from tapping to casting are key. Indeed, the duration between the heat tapping at the converters/electric arc furnaces and the casting should be kept as short as possible in order to reduce the needed energy for heating. This can be achieved with the support of the melt shop scheduling tool. At the same time, this tool should also optimize the plant throughput, create a schedule that avoids bottlenecks, plan enough buffer in the schedule to cope with unplanned events and ensure the casting of the sequence.

Online Heat Scheduling ©PSI Metals

Opportunity #2: Reducing Energy for Heating with Ladle Planning

The equipment’s preparation also consumes energy. It’s important to have a good ladle management system to always have a clear overview of the available equipment and their parameters in order to use them efficiently and plan maintenance operations. A ladle planning solution also enables the melt shop operator to better choose which ladle should be used for each type of heat, depending on the melt shop schedule as well as the ladle parameters (temperature and wear), so that the energy used for heating equipment can be minimized.

Opportunity #3: Reducing Energy Consumption with Hot Charging Optimization

In the rolling stage, energy is consumed in the reheating furnaces. The hot charging of slabs to the reheating furnaces of a hot strip mill, in an integrated steel plant, results in an important energy consumption reduction. At the same time, it reduces the inventory and the slab handling. However, it is a challenging task to create production schedules for both the continuous casters and the hot strip mill that maximize such hot charging. The main reason is that different and conflicting process constraints apply to those lines. For the caster, it is important to minimize grade and width changes. While for the hot strip mill, thickness jumps and edge wear constraints must be considered. Of course, logistical constraints such as order due date and downstream capacity constraints must also be considered in any solution, which complicates the scheduling task even further.

Caster Scheduling ©PSI Metals

Opportunity #4: Improving Schedule Quality with Dynamic Re-Allocation while Scheduling the HRM

Some opportunistic hot charging can also be done thanks to the re-allocation process, carried out just before producing at the hot rolling mill. This re-allocation process can be combined with the scheduling process at the hot rolling mill. By being able to change the allocations dynamically, while scheduling the hot rolling mill, more options are provided to improve the schedule quality. For example, the right order can be allocated to the slab in order to bridge a width or thickness jump. This will even enable you to still schedule the mill as you reduce the stock in the slab yard. By being able to re-allocate your slabs just before producing a sequence, you can also reduce the number of unpiling operations in the slab yard.

Hot rolling mill scheduling ©PSI Metals

Opportunity #5: Minimizing Scrap with Reactive Cutting Plan Optimization

The stock in the slab yard could also be reduced by avoiding unallocated slabs directly at the caster exit. Through the use of the Level 2 information about an actual production deviation (quality, width, grade, steel quantity in the tundish, closed strand, e.t.c.), a reactive cutting plan optimization at the caster can decide how to cut a slab based on given characteristics, with consideration to the order book. Thanks to this reactive service, the slabs will be cut at the right length and will remain allocated to existing orders at the caster exit, even if the production deviates from the plan. The added value of this process is especially high if your slab dimensions are very heterogeneous, as in that case the unallocated slabs are more difficult to be re-allocated to other customer orders and may lead to some waste.

Reactive cutting plan optimization ©PSI Metals

Opportunity #6: Minimizing Waste with Material Allocation & Coil Combination

In the solid phase, material waste can also be minimized thanks to the material allocation and coil combination tools. The material allocation tool will find an optimal production order to be assigned to a complete coil in stock. But in case of smaller production orders, different pieces of a same input coil can be allocated to different orders. The coil combination optimization combines the material allocation problem with a cutting plan generation and scrap minimization. This assignment process encompasses the optimization of feasible cutting patterns in order to minimize the material losses.

The coil combination tool can also be used in design mode in order to calculate the optimal dimensions of a coil to serve some smaller orders. With this solution, a coil can be produced at the right dimensions to exactly generate those output pieces and therefore minimize the waste.

Opportunity #7: Aligning the Schedule to the Available Energy with an Energy Consumption Forecast

In order to respect some maximum energy consumption constraints from your energy provider, an energy consumption forecast can be calculated as part of the scheduling process. This will give you the overview of your energy consumption per line and per product for a better monitoring. It will also enable you to adjust schedules in order to avoid exceeding some maximum energy consumption limits. With this visibility, you can better balance the energy consumption in time and at the end pay less.

This energy consumption forecast can also be used to adjust the production plan to fit to the available green energy quantity in time.

Energy consumption forecast ©PSI Metals

A Mighty Tree Starts with a Seed – Let’s Plant it Together!

It is easy to calculate how all of these solutions benefit the business and bring better financial results. But they also have an impact on CO2 emissions! By scrap reduction alone, that can be achieved by the usage of a reactive cutting plan, emissions of up to 1.9 tons of CO2 can be avoided for each ton of scrap.

In conclusion, better planning & scheduling not only lead to better production efficiency, but also demonstrable and significant environmental benefits. The cost of such solutions are a small fraction of the massive investments required to change production equipment’s and they can be implemented much quicker.

Do you want to know how PSImetals Planning can help you improve your supply chain sustainability?

Leave the road, take the trails and join us in exploring the nature of your supply chain! Follow our “Explore the Nature of Your Supply Chain - Smart Plans for Sustainable Metals Production” campaign, which is enriched with many exciting blog articles and exclusive webinars!

Jérémy Coppe

Head of Competence Center Planning at PSI Metals

After several years developing the standard PSImetals Planning components, Jérémy Coppe implemented several solutions in many major steel producers all over the world, such as Coil Combiner, Line Scheduler, Caster Scheduler and Online Heat Scheduler. Jérémy also worked for 3 years as an analyst in the R&D project FutureLab. As the Head of Competence Center Planning, Jérémy is now managing all the standard software developments for PSImetals Planning components. Jérémy’s interests include sports and wine tasting.