AS_6

CONTROLLO

tecnica

Automazione e Strumentazione

Settembre 2017

- Optimization of boiler and gas turbine loads, maximizing

the most efficient machine utilization (as defined by a higher

level closed-loop rigorous optimizer).

APC applications need to cover the all steam production side and

meet steam demand as required. They permit to address significant

issues like the one depicted in

Figure 5

where the HP steam let-

down valve and flow are reported. More than 10 t/h of HP steam is

downgraded during normal operations in this example.

In this specific case, benefits achieved by deploying the APC solu-

tion on this steam network were above $1.5 million per year if

counting only those due to reduced let-down flows and vent flows.

A more comprehensive and efficient solution can be built where a

model-based optimizer is also used to drive the APC system based

on overall economics and efficiencies. The

Figure 6

shows a

very simple case where an optimizer suggests swapping the load

between two boilers to achieve around $ 3,000 per day of benefits.

Many opportunities like this example exist in a Steam Network.

The Path Forward to a Best in Class APC Program

APC benefits on major units are well understood and accepted.

However, to achieve best in class performance in

margins and operational excellence, organizations

must expand their APC footprint to secondary units.

Organizations often do not fully understand the ben-

efits that are available to them and/or face a shortage

of engineering resources to capture APC benefits from

secondary units. APC engineers often have a signifi-

cant workload maintaining existing applications. This

is often due to the use of traditional APC technology.

Advances in APC software like

Adaptive Process

Control

empowers end users, automates many tasks,

adapts and calibrates models in the background with

no disruption to operations and provides increased

robustness. All of this can help reduce the APC main-

tenance workload and maintain peak APC perfor-

mance with ease. Advances in APC technology can

enable organizations to shift focus from just maintain-

ing existing APC applications to deploying additional

APC applications, capturing benefits from secondary

units and enabling a best in class APC program.

Figure 5 - Let-down flow rate and valve position

Figure 6 - Boilers load swap