Mitsubishi Plant Optimization System

A Mitsubishi Plant Optimization System (MHI-POS) can calculate the efficiency of each major piece of equipment as well as the overall plant efficiency by inputting actual plant data into an efficiency calculation program.
On the other hand, the calculation result when the ideal plant data, that is the plant data at the time of the design, is input into the efficiency calculation program can be interpreted as the optimal efficiency of each major piece of equipment.

If you compare those two efficiency values, they are always different.
The actual efficiency can be lower because of things like wear and dirt on the heat exchangers.

By comparing the actual efficiency and the optimal efficiency calculated from the design data, an MHI-POS can find out where maximum efficiency drops occur in the power plant.

Therefore, if you use an MHI-POS, you can find which part of the system you should spend a limited budget on in order to improve the plant performance effectively.

Functions

• Efficiency drop display
  The actual efficiency and the optimal efficiency of a major piece of equipment can be displayed as values and bar graphs on the plant system diagram. The efficiency drop can be converted to a monetary value to be displayed as an operational loss when you compare the actual plant status and the calculated optimal status.
• Validity of process values can be verified
  When efficiency is calculated, it is important that the process values used for efficiency calculation are precise.
  Consequently, the efficiency calculated from data received from a transmitter with large errors is not reliable.
  This system checks the validly of major process values by using consistency checks between major signals.
  For each major process value, the correlation data between the signal and the correlated signals is predefined in the system. If the process value stops satisfying this correlation, the signal is deemed unreliable and is excluded from the inputs of the efficiency calculation.
  Instead, the interpolated value calculated from the plant model is used.
• Historical trend graph for efficiency and efficiency drops
  You can save measured process values, calculated actual efficiency, calculated optimal efficiency, and so on into a historical trend graph and view the data at your convenience. As a standard option, you can save the data of the past three years in the system, and you can compare the current efficiency values with previous values.
• Analysis for the cause of efficiency drops
  An MHI-POS can analyze the root cause of efficiency drops.
  If the difference between the actual efficiency and the optimal efficiency exceeds the threshold, an efficiency drop alarm is generated. At the same time, the program for root cause analysis on efficiency drop automatically starts.
  The root cause analysis function uses the knowledge base of the relationship between an instance of efficiency drop and its probable cause based on the know-how and experience MHI has accumulated over many years. Triggered by an efficiency drop alarm, the condition at the time is checked against the knowledge base, and guidance about the probable causes of the efficiency drop is displayed.
  If a new type of incident not included in the knowledge base occurs, the user can update and customize the knowledge base.

Main Equipment calculating the optimal efficiency by MHI-POS

An MHI-POS calculates the efficiency drop for the following major pieces of equipment.
(a) Boiler
(b) Feed Water Heater
(c) Turbine Condensor
(d) Turbine
(e) Main pump

Data required for POS

An MHI-POS needs the heat balance data of the plant because it needs to calculate the efficiency for each major piece of equipment using a plant model.
If DIASYS Netmation is introduced, the necessary data for the MHI-POS can be acquired from an accessory station (ACS). In order to design an MHI-POS, the following data is necessary in addition to the data acquired from the ACS.
(a) Electric current values at the main pumps and fans
(b) Generated heat from the fuel used
(c) Fuel costs
(d) Electricity rates
(e) Others

System Configuration

An MHI-POS has the following system configuration.

MHI Pos.pdf