Virtual reality: Plant simulation software

Plant simulation software aids in plant management, and bridges the gap between theoretical and actual production capability.

When asked about their operating plant’s capabilities, most aggregate producers either know exactly how much material the plant makes, but don’t know what it is capable of making – or they know what the plant’s capacity may be, but don’t know its actual production. If you don’t arm yourself with both knowledge of your plant’s capacity and an accurate measure of your production output, you can’t truly manage your production process.

In reality, most plants are underutilized. This is where process flow simulation software is a useful tool that producers, engineers, equipment manufacturers and equipment dealers can use to simulate the flow of material through aggregate and mining operations. The software enables users to build both simple and complex crushing, screening or washing plants on their computer screens.

By choosing equipment types and settings, monitoring flow rates and gradations at desired points, and then virtually running the plant, users can compare calculated results to actual field results. When validated by field sampling and measurement, the data produced with process flow simulators can become one of the most critical components of a plant’s performance measurement. In fact, without plant flow modeling capability, it is almost impossible to simulate – much less manage – the processing options that are available in most aggregate plants.

Simulation software helps identify and solve a variety of operational problems, such as bottlenecks and inefficiencies, highlighting the differences between what the plant should produce and what it does produce. Users may then simulate unlimited “what-if” scenarios to visualize options – such as replacing equipment or tweaking feed rate and gradation settings – to accurately assess the impact of these potential changes on maximizing plant efficiency and achieving optimum production mixes.

Process flow simulators have become more and more sophisticated in the past 20 years, and today can replicate a plant’s actual production capabilities with surprising accuracy. These tools are designed to reduce calculation time and increase operational productivity. In addition to assisting producers in improving their plants, such simulation software also is an excellent tool for the design of new plants in order to optimize the proposed plant layout and identify what equipment will best meet intended goals.

Actual meets theoretical

The value you gain from process flow simulation requires accurately defining both the current production and the engineered capability of your plant. Building a simulation model begins with understanding the manufacturers’ stated capacity for each piece of equipment in the process – from the feeders, to the crushers, to the conveyors, to the screens.

Measure production by setting up belt scales on conveyors that come off of every crusher. Note: If you are setting up belt scales only in certain locations, it is nearly impossible to know actual production. Aggregate plant simulation accuracy also requires basic assumptions about the material and the way the equipment is run: Is the equipment fully loaded or under-loaded? Is the material wet or dry? Is it hard or soft?

The bottom line

Process flow simulators will not miraculously identify why a plant is operating sub-optimally. In addition to knowing actual equipment capacities and accurately measuring production, the best tool for bottleneck elimination during aggregate processing is also careful observation. By watching amp gauges, you will know if a crusher is running at capacity.

Blinded screens slow production and can send good rock to the waste pile. Failure to choke feed a cone crusher not only creates a bottleneck, but also can affect product quality. At the same time, process flow simulators will identify and highlight deviation from the plant’s theoretical capability or the established benchmark.

The future of process flow simulation

The world of process flow simulation software is always in a state of development. For instance, for the first time ever, simulation software now has the ability to directly tie aggregate production into sales forecasts.

We all know plants run to meet annual sales demands, and need to do this within scheduled hours. Additionally, many plants make products in different combinations at different rates, and need a plan to match production to sales volumes. Through process flow simulation, once an accurate plant model is in place, production scheduling software that is tied into the simulator now allows producers to virtually “test drive” production scenarios using enhanced operational modes – providing a simple method to plan for the year.

The software can plan production based on sales forecasts up to 12 months out; determine inventory (including existing inventory); schedule operating modes based on inventory and sales forecasts; balance production to sales; and determine sales shortfalls.

How does it work? Once a benchmark for plant performance is set (actual production rates and plant availability), the producer should use the simulation software to optimize the plant. From there, the producer can enter sales forecasts; match each sales product to production products or blends (i.e., stockpiles); enter required sales, which are prioritized over higher revenue sales; and enter monthly prices by sales product.

The next step is to enter inventory minimums, maximums, cap limits and value; enter plant availability (hours per day and days per month); select available operating modes; and enter the previous month’s closing inventory. The producer also may enter the previous 12 months’ forecast and production to use for comparison, if desired.

The production scheduler software will solve for the highest revenue, while meeting required sales commitments and inventory constraints as it calculates the shortfalls by month for each sales product. By automatically selecting the best combination of operating modes in the available scheduled time, the software shows the production by mode and the inventory trends over the sales forecast. It provides outcomes – by stage and for the entire plant – with results that are exportable to Excel.

Take note

By comparing actual, measured field results to the program’s calculated results, you can identify your plant’s bottlenecks and inefficiencies.

Bryan Lewis is the president and founder of Bedrock Software, the creator of the AggFlow process flow simulation software. He has a degree in nuclear engineering from Oregon State University. www.aggflow.com