Energy can neither be created nor destroyed, energy can only be transferred or changed from one form to another.

The above is the First Law of Thermodynamics, and it is called the Law of Conservation of Energy. We all read it in school and very rarely remember this law whenever we eat food for energy, whenever our vehicles consume fuel to run, whenever we switch on the bulb to get light, or when plant personnel press the start button for a steam turbine generator.

Energy needs to be used efficiently, otherwise it is waste of natural resources and money. Yokogawa Electric Corporation (hereafter will be used as Yokogawa) and KBC (a Yokogawa company) work in the field of Energy Management to conserve and optimize energy so that Manufacturing units can run their plants efficiently while also helping the environment.

In February 2013, Yokogawa announced the addition of Soteica Visual Mesa's best-in-class energy management and optimization solution services to its portfolio of plantwide energy management solutions (EMS). The solution can reduce the total energy cost of utility equipment in the plant by 2 to 5% per year, and reduce the site CO2 emission, thus conserving the environment.

Visual MESA Energy Management System consists of three solution suits:

The solutions share the same platform and use the same digital twin model. Users can have all three of them, two of them in any combination or just one, based on their needs. Some sites are suitable for both real-time optimization and monitoring (VM-ERTO + VM-EM) while a smaller and simpler site would benefit with only energy real-time monitoring (VM-EM).

VM-ERTO is the leading real-time digital twin for energy system optimization, including discrete variables. In open loop, the system works in advisory mode. It is up to the operators to implement the system recommendations. When in closed loop, the system automatically sends the optimum set points directly to the DCS controllers.

VM-EM is specifically designed for energy system monitoring, such as, KPIs calculation, balances, historization, etc. and optimization of only continuous variables.

VM-MPO is the energy management tool for the optimal scheduling of utilities assets.

How does VM-ERTO work?

1.     The Process unit sets the demand of utilities such as: Hydrogen, Fuel, Steam, Water, and Electricity to Utility Section of the Site

2.    Through DCS the measurement of the demand is sent to the energy system software

3.     Simulation model uses first-principles for the target utility unit. The model can simulate behavior of various equipment such as: boiler, boiler feed water preheater, steam turbine generator, gas turbine generator, heat recovery steam generator, deaerator, and letdown. The fuel line and utility line connect the equipment in the model. The model also includes fuel price information and environmental constraints as conditions. The simulation finds the optimized combination of energy utilization source, considering mainly two constraints.

3.1. Lowest Cost of total Energy Utility

3.2. Emissions Regulation based on Local and National Laws.     

4.     There are two options for regulating utility

4.1. Closed Loop: VM-ECLRTO sends the optimum set points to DCS automatically

4.2. Open Loop: VM-ERTO issues the advisory report, and operator has the choice to change the set points on DCS Manually

Below is an example which explains that how VM-ERTO finds the gaps between actual and optimized operations

For Turbine or Motor swappable drive or unit, VM-ERTO chooses the best for energy cost.

On the left-hand side of the above figure, the Steam Turbine and Motor connect to the same shaft to drive the pump. In normal operation, one of the two drivers supply mechanical power to the pump. So, there is a choice on which driver should be used. On the right-hand side of the above figure, there are three pumps, two are driven by steam turbine, and the remaining one is driven by motor. In normal operation, working two of the three pumps satisfies water supply. In this case, there is choice that which pump should be used.

VM-ERTO creates the Report and suggests the best option to the DCS Panel Operator to choose or directly changes the set point if it is connected to DCS directly through closed loop connection.

The below figure depicts the Energy Monitoring feature of Visual MESA Energy Management System. From the model, several parameters can be used to create a report and to make a trend for generating history.

For example, in the below model one can check several parameters

1.     Steam turbine: Generated power, Efficiency, etc.

2.    Steam line: Temperature, Pressure, Enthalpy etc.

Steam header: Inlet flow and outlet flow. If there is big gap in between these flows, then there is possibility of steam leak or instrumental error.

Data Validation is a very important step for correctly measuring the data and then finding the optimized set points by running simulation models.

The figure below is an example of a Visual MESA Operation Report, which explains the gap between current (actual) operation and optimized operation, which ultimately reflects in terms of money savings per hour basis.

Success Story

Location: A petrochemical plant located in South East Asia

Customer Challenge: To reduce total cost of energy in real time and integrate their utility system.

Solution: Yokogawa Implemented VM-ERTO including simulation model, optimization and KPI calculation on their utility system.

Benefits: Customer’s Engineers were trained on new system of Energy Management, the customer realized ROI which is less than one year and CO2 reduction.