Need help with process calculations for heat transfer oil furnaces?
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The heat load of the heat transfer oil furnace is 3 million kcal/h; it is now necessary to calculate how many Nm3/h of natural gas is required as fuel Natural gas is expressed on a methane basis. I have the following questions for assistance: 1. If calculating manually, what are the approximate steps? 2. Is there any software that can calculate this process? What software? 3. Can the Aspen software calculate this process? If possible, how should the calculation for this process be carried out? Which module or combination of modules should be chosen to simulate this process? 4. After receiving this task, I have the following questions regarding calculations: a. What temperature and pressure are generally chosen for feeding fuel into the heating furnace? b. At what temperature and pressure does the fuel undergo combustion reactions in the furnace? c. How is the air used for combustion handled in the calculations? I would appreciate guidance on the above issues from experts in heat transfer oil furnaces. Thank you!
Estimation: Natural gas calorific value, combustion rate, heat transfer efficiency (heat transfer coefficient), to meet 3 million kcal/h
When calculating the fuel amount in this way, does it still need to take into account the effect of nitrogen in the air on heat? 1. Both natural gas and air enter the heater for combustion at room temperature. 2. Natural gas and air enter the heater for combustion after being preheated to 150°C by flue gases. Do these two scenarios have any impact on the calorific value of the natural gas fuel? Does it have an impact on the calculated fuel amount? Also, can this process be simulated using Aspen software? Thank you!
1. Manual calculation: The calorific value of methane is 8578 Kcal/Nm3; therefore, for natural gas, the value is 3*10^6/8578 = 349.7 Nm3/h. 2. Boiler calculation software includes a function for combustion calculations. 3. The Aspen software can simulate this process. You can check for issues with combustion using the Aspen software on the site. 4. a. The choice of temperature and pressure should be determined based on the performance of the burner and the structure of the furnace. The higher the fuel temperature, the better; for a boiler with a capacity of 5 T/h, the gas pressure range is 10–30 kp. b. The fuel conditions meet the three requirements for combustion; the furnace pressure depends on the design parameters, with the temperature being around 2000 degrees or so. Generally, only the furnace pressure is of concern. c. The air required for combustion can be determined by referring to the excess coefficient specified in the boiler’s calculation documents. According to TSG ZB001, the excess factor should be lower than 1.2.
Both natural gas and air enter the furnace for combustion after heat exchange with the flue gases