Combustion Boiler Control

Combustion Boiler Control

Properly handled combustion boiler can be a very efficient source of energy. The task however can be quite complicated, when taking into account possible anomalies and of course the impact on our environment. That's why the proper analysis of the exhaust gases and then control of the burning cycle can bring not only cost savings but also safety and environment friendly results.

Application Overview

Let's take a look at the system of six industrial boilers. Each boiler can have up to 8 analogue inputs, one analogue output and some digital IO points. All data need to be scaled and should have min/max alarms. All sensors need to be cleaned on time or failure basis, which also has to be monitored by the program. Most of the data measured need to be calculated in different engineering units, depending on fuel used in the burner. The data then needs to be logged and stored for the future reference and analysis.

XL6e with SmartMod I/O

Based on the system requirements, Horner has developed solution consisting of the XL6e as a main controller, together with multiple SmartMod IO modules (Modbus RTU), one module per boiler. Controller uses the Micro SD card for all the necessary datalogging and because of the embedded Ethernet port, the whole application can be monitor and even controlled via Web Server or Envision RV.

Implementation

During the first stage of implementation, our XL6e was used as an exhaust gases analyzer. It was achieved by multiple probes connected to each SmartMod IO measuring level of gases like CO, CO2 or NO, a pressure and a temperature (up to 8 signals). The controller then is scaling, calculating and storing the values on the flash memory. This data was crucial to determine whether the process was environment safe or not. Second phase was embedding the control algorithm into the burner working cycle and dosing the oxygen input.

Cscape Program Example

Boiler Automation example

The Cscape configuration file consists of:

  • Hardware configuration (XL6e + SmartMod I/O)
  • Scaling procedures (Logic Modules -> Main -> Scaling)
  • Finding Min/Max Values (Logic Modules -> Main -> Min_and_Max)
  • Control procedure (Logic Modules -> Main -> Control)
  • Handling Alarms (Logic Modules -> Alarms)
  • Datalog configuration (menu Program -> Datalog Configuration)
  • Application Screens (Overview + Alarm screens)

(Cscape 9.20 SP1 or higher needed)

Summary

Horner solution was chosen because its flexibility (very easy to increase the number of boilers), powerful datalogger and several remote access options. Also the working conditions (wide temp. range, dust and electrical noise) were too harsh for some of the competition. It was also important for the maintenance team to be able to easily see what's going on and quickly determine the level of pollution (hence colourful, good quality screen).

The benefits for the plant manager are quite obvious. Proper oxygen content control optimizes the air/fuel ratio which equals energy savings. The process itself becomes safer, because whenever an anomaly is detected, the burning cycle can be corrected. To sum up: correct combustion means money savings and safer and cleaner plants.