Frequently Asked Questions

Q: We are interested in buying Combustion Expert, but we are not sure it will fill our needs. Is there a trial period or demo program?  Is there an easy way to pay from Spain ?

A:  The software ships with a lock that allows the user between 15-30 days unlimited operation. After this period you must register to run the program. You get your permanent registration code, when we receive our payment. If you decide to pay up front you have 14 days no questions asked return policy. 

The easiest way to pay outside US is by Bank wire transfer. Your local bank can make this transaction for you. We accept Credit Cards or Cashier's Check, but we are flexible. Terms are 30 days net. 

Q: Is there an easy way of converting the calculated results from US units to International measuring units?  

A: Yes! First save the results in a project file. Next restart the program, but select SI units. Open the project file and copy data to program. 

Q: How can I add a company logo on my reports?

A: There are two ways to do this. First there is a quick way. There is a bmp file called bizlogo.bmp in the program directory. This file is copied to every report on the top left hand corner. To create your own logo you can scan in a picture or create a new using paint by clicking on Logo in the "Process Heat screen".

Q: How can you add a new compound like Hydrogen Sulfide to the fuel composition?  

A: Click on the name of the compound you want to edit. Then enter the new name, the number of C,H,O,N and S atoms it contains (H=2,S=1) enter the heat of formation (can be found in Chemical Handbooks such as CRC 82nd Ed,CRC Press) (Hf =-20.6 kJ/mole). The program will fill in the rest.

Q: What is the difference between fuel efficiency and process efficiency and how are they calculated?

A: The fuel efficiency is based on the useful heat of the fuel.  Eff  =  Useful heat / gross heat input.  The process efficiency is based on the theoretical heat required, equal to the heat required (to increase the temperature of the process from initial to final temperature) divided by the gross heat input ( = grossHV x fuel flow). Ideally the two should be the same, but if the required heat is different from the useful heat it will differ.

Q: How is the compressibility calculated and can you calculate the compressibility at other pressures than those for combustion?

A: There are two programs for calculation of compressibility; detailed method and gross characterization method. The first method uses the viral equation of state and its mixing rules and valid up to half the critical density. The second method is a correlation method and can be used to estimate the compressibility if the mixture contains compound with unknown viral coefficients. Yes, you can calculate compressibilities for pressures up to 750 psig.

Q: Doesn't temperature and dilution change emission values from the stack ?

A: Yes, you are correct the emission changes with dilution. To bring all values back to a standard that can be used for comparison we refer volumetric  emissions to an oxygen level of 3 vol%. NOx and SOx are also calculated as lb/ton product and lb/MMBTU both these values are not dependent by dilution. You can also use a nifty calculator to calculate emissions at any oxygen level. The temperature itself will not change the volumetric values when expressed in part per million (ppm) or per cent. 

Q: Are there different standards for calculation of heating values?

A: First there are two different heating values (upper and lower). The Upper heating values refers to liquid water as the final product, whereas the lower heating value refers to gaseous water as the final product. European heating values often uses 1 atm, 25*C as a reference state, whereas U.S uses 30 in mercury and 60 degF for measurement or calculation of heating values.

Q: Can I correct the stack gas calculations by using actual measured dry gas composition ?

A: Version 3.0 allows you to do this correction. First do the calculations as usual. Then select "Dry gas". Check that H2O = 0.0000 and enter your measured values. Next click on "Dry gas" again and then on "Calculate". The values used in the new calculation are based on the measured values.

Q: How does measurement of residual oxygen using a stack gas analyzer compare with calculating air/fuel ratio?

A: The stack gas analyzer is a good help in determining the air/fuel ratio. Used properly they both give the same results. However, the following aspect should be considered. (a) any air leaks in the furnace walls will give false readings (b) the sampling procedure can introduce errors (c) the operator often relies on a single value taken once a week or once a day, but Air pressure, temperature and humidity changes hourly.

Q: Where can I obtain information in my local area about barometric pressure, temperature and humidity data ?

A: I personally like the weather bug. It is a free software that you can download to your computer from http://ww3.weatherbug.com but you can also get weather information from your local TV or Radio stations.

Q: I am thinking of using the net heat released in an oil fired furnace to calculate the flow rate of natural gas when converting the furnace to a natural gas fired furnace. Is this a correct way of doing it?

A: You may get the right magnitude by doing this comparison. However, when doing a fuel conversion it is the transferred (or useful) heat that should be compared. Unfortunately these calculations are too complex to do without a computer program like our Combustion Expert. Not only will the radiative heat transfer be different but also the stoichiometric ratio and the flame temperature.

Q: What advantage will your software provide for calculating the efficiency? Doesn't the fuel consumption provide enough information about the process efficiency?

A: That is a misconception! For all I know you could fire the burner outside the furnace but it will do the process no good. The software provides you with a detailed calculation to show how much heat is going into the process, how much heat is reflected, how much heat is absorbed, how much heat is radiated from its surface what the gas emissivity is, what your furnace losses are. It allows you to change the fuel and is composition as well as the air/oxygen composition, the furnace dimensions, the wall temperatures and emissivities. All factors influencing the process efficiency.

Q: Can you handle calculations for combustion where the flue gas is recirculated?

A: The recirculation does not change the results of the calculated stackgas composition. The only change is in the composition of the incoming components of the fuel. However, should the temperature of the recycled stack gas be lower than the outlet stack gas temperature it will effect the stack gas losses and the efficiency.

To obtain a demo CD . If you live within the 48 continuous states in US, send us $9.95 to cover our cost for S & H. For Hawaii, Alaska and all other countries the S & H cost is US$19.95 Make a note of which operating system you are using as there are some compatibility issues.