Friday 31 May 2013

Optimising Combustion Efficiency in a Boiler

Getting into the basics of combustion, the ideal amount of air required to burn a given quantity of fuel is referred to, as stoichiometric  air. This is calculated based on the fuel composition. The level of mixing of air and fuel, that is required for complete combustion, is practically never achieved. If we supply the stoichiometric quantity of air for combustion, we would almost ensure that the combustion is incomplete. Hence the burners are designed with a particular level of excess air that ensures proper combustion.

Normally boilers are designed with excess air levels at around 20% for oil and gas fired unit at full load conditions.

The extra air that is supplied carries with it some heat which is not recoverable. So higher the excess air, higher are dry flue gas losses. Though a boiler is designed for a particular level of excess air, when a unit is commissioned, it is tuned to a particular load. Over a period of operation of the unit, there is a tendency for deviations from the tuned values, due to:-
- Variations in the fuel quality like density, viscosity, flash point etc
- Variations in the fuel pump outlet pressure, firing rate etc
- Normal wear and tear of fuel system components
- Vibrations

Conventionally, there is no feedback mechanism to regulate the combustion air inflow, to account for the variations and the firing rates. Due to the above reason, we end up with high fuel consumption.

With undesired high excess air, one may end up burning extra fuel. Also the monitoring of oxygen levels is also equally important. Too low quantity of air supply will lead to unburnt/incomplete combustion and subsequently soot formation in the boiler. Thus, it is very important to optimize the air flow for efficient combustion.

The losses in a boiler are:
Stack loss or Heat loss (highest 8 to 10% in a well tuned burner)
Moisture and Hydrogen loss (depends on the fuel and hydrogen & moisture content in it), Radiation loss (about 0.5%)
Unburnt fuel loss (negligible in liquid and gaseous fuels), etc. 

When total of all the losses is subtracted from 100, we get efficiency. Typical boiler efficiency for liquid/gaseous fuels is in the range of 88 to 90%. Thus all the losses put together will be in the range of 10 to 12% of which the stack loss is around 8%. 
Thus stack loss is 67% of total losses put together, and most important to monitor.

Testo Solution: 
For combustion efficiency optimization , it is always O2, CO, and CO2 that are monitored. O2 tells us the type of combustion, either complete or incomplete. The CO levels tell us how much fine tuning is required for the air to fuel ratio.
Hence, for all small boilers, testo 320 and testo 330-LL is the best solution. While for large power plants and bigger boilers & furnaces, testo 340 and testo 350 are the right solutions. Offcourse with O2 and CO sensors, CO2 is always calculated.

For more information, click here or write to us at info@testoindia.com

Friday 24 May 2013

Detecting Electrical Unbalance and Overloads with Thermography


Thermal images are an easy way to identify apparent temperature differences in industrial three-phase electrical circuits, compared to their normal operating conditions. By inspecting the thermal gradients of all three phases’ side-by-side, technicians can quickly spot performance anomalies on individual legs due to unbalance or overloading. 

Electrical unbalance can be caused by several different sources: a power delivery problem, low voltage on one leg, or an insulation resistance breakdown inside the motor windings. Even a small voltage unbalance can cause connections to deteriorate, reducing the amount of voltage supplied, while motors and other loads will draw excessive current, deliver lower torque (with associated mechanical stress), and fail sooner. A severe unbalance can blow a fuse, reducing operations down to a single phase. Meanwhile, the unbalanced current will return on the neutral, causing the utility to fine the facility for peak power usage. 

What to check?

Capture thermal images of all electrical panels and other high load connection points such drives, disconnects, controls and so on. Where you discover higher temperatures, follow that circuit and examine associated branches and loads. Check panels and other connections with the covers off. Ideally, you should check electrical devices when they are fully warmed up and at steady state conditions with at least 40 % of the typical load. That way, measurements can be properly  evaluated and compared to normal operating conditions. 

What to look for? 

Equal load should equate to equal temperatures. In an unbalanced load situation, the more heavily loaded phase(s) will appear warmer than the others, due to the heat generated by resistance. However, an unbalanced load, an overload, a bad connection, and a harmonic imbalance can all create a similar pattern. Measuring the electrical load is required to diagnose the problem. 

Testo Offering: 

Testo Thermal Imager 875i offers you an entry into professional thermography. It quickly and reliably quickly and reliably detects anomalies and weak spot in materials and components. Thanks to an imaging process, energy losses and cold bridges as well as damage or overheating in industrial systems are detected without contact. Whereas with other methods, cable or pipeline systems must be exposed over a large area, with testo thermal imager 875i, a single glance is enough.

Click here for more information or write to us at info@testoindia.com

Friday 10 May 2013

Optimise Your Indoor Climate…With Easy HVAC Analysis Like Never Before !


When it comes to energy, a building is a self-contained system, which can only be optimised as a whole. 
The HVAC All-Rounder - testo 480
Testo measuring technology supports HVAC tradesmen, facility managers, architects, supply engineers, experts and energy consultants for the same.


You probably come across this situation often: employees can no longer concentrate due to a lack of fresh air. It's either draughty in the workplace or it's too hot. This results in less efficiency and high energy costs for the company. A naturally pleasant climate and air of a high hygienic quality are key to a healthy working environment. That is why air technology system (VAC system) experts measure and evaluate climate and air quality. Testo measuring technology for all relevant parameters helps you to carry out this work efficiently, safely and with time savings.

HVAC is one of the fastest growing industries in India. As the number of buildings, green buildings, greenhouses, commercial complexes, malls, hospitals, high rise buildings and offices increases, more is the requirement of HVAC.
By 2050, the International Energy Agency in Paris expects a global increase of more than 300% in building areas, –which will have to be heated, ventilated and cooled. This makes the efficient and environmentally sound use of energy even more important. Current and future legislation prescribes strict measures to reduce consumption. Companies are optimizing energy control in order to lower costs. The job of the Facility Manager is now becoming “Facility Energy Manager”.


Values for flow, temperature, humidity, pressure, illuminance, radiated heat, turbulence and CO2 concentration can be recorded with our high-end testo 480 climate measuring instrument in a single step. Its intelligent probes give you accurate measuring values, with deviations being automatically eliminated after calibration. The robust multitaskers from Testo such as testo 480 and testo 435 enable you not only to carry out measurements in compliance with standards, but also to produce professional reports quickly using PC software.

Testo offers you, as specialists, accurate, quick and easy to- use measuring instruments to ensure thermal comfort when it comes to air conditioning in work areas. That way, you ensure a constantly controlled climate in store rooms and cold rooms, in production halls and server rooms. Click here for more information or write to us at info@testoindia.com