Analyzing Hydrocarbon Burner Gases

The fuel that makes a Bunsen burner work is a mixture of alkane hydrocarbons. One type of fuel is natural gas, whose primary component is methane (CH4). The other type is called LP gas and consists primarily of propane (C3H3). In this experiment, you will use the ideal gas equation to help identify the main component of your classroom fuel supply. 

What type of alkane gas is used in the burner fuel supplied to your laboratory  

Prepare all written materials that you will take into the laboratory. Include safety precautions, procedure notes, and a data table. 

Use the formulas of methane, ethane, and propane to calculate the compounds molar masses. 

Given R and gas pressure, volume, and temperature, show how you will rearrange the ideal gas equation to solve for moles of gas. 

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The total gas flow from the reactor oudet is monitored on-hne by an FTIR analyzer (MKS Multigas 2030) and an EI-MS (V F, H-sense). The FTIR is operated at a cell temperature of 463 K. A sample gas cooler is installed between FTIR and EI-MS to protect the EI-MS from excessive amounts of water in the gas composition. The sample gas cooler is set to 278 K to remove water and other species, e.g., unconverted hydrocarbons, which condense at these conditions. Additionally, an IMR-MS (V F, Air-sense) and a GC-MS (6890 N, Agilent) can be used. The total gas flow is fully oxidized in the flame of a bunsen burner after it leaves the analytics. To quantify the total gas flow that reaches the FTIR, an adapted external standard method is used (Hartmann, 2009 Hartmann et al., 2009 Kaltschmitt, 2012). 

A sample of the air/gas mixture is fed into the analyzer cell at a fixed rate. The cell and sensor are maintained at approximately 1500°F (812°C). the sample ignites, burners and the hot products of combustions (POC s) flow past the ceramic/platinum sensor and produce an electrical voltage proportional to the amount of excess O2 or excess hydrocarbon. The signal is amplified, conditioned and lineraized. A discrete step function occurs when excess hydrocarbon (unburnt fuel) is present in the POC s. This signal is in used an input to the PLC which has a PID control loop output to operate a gas flow control valve to maintain the specified Plasma Valve. 

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