The high content of carbon dioxide in natural gas is a major problem when utilizing natural gas. This is due to the acidity of the carbon dioxide, which will pose problems for the extraction, production and transport of natural gas. Carbon dioxide deposits on the packaging material due to the transfer of the cold energy stored in the packaging material.
The dynamic behavior of the packed bed is described using a one-dimensional plug flow model. High CO2 content can cause corrosion problems in natural gas extraction, transportation, production (S.A. Enbenezer, 2005). For the separation of high CO2 content in natural gas, a separation method using a dynamic packed bed is proposed for the simultaneous separation of CO2 and H2O from natural gas.
In addition, it is also important to investigate the separation characteristic of CO2 and H2O from natural gas in the capture cycle. This technology makes use of the difference in the dew point and sublimation point which will enable the separation of CO2 from flue gas. In addition, there are some of the cryogenic separation technologies that have already been applied for commercial application.
Mass transfer processes in dynamic packed bed are investigated using ID plug flow model.
Experiment 1: Calibration Curve for the C02 and CH4 Mixture Using Gas
The gas chromatography to be used is the Gas Chromatography Flame Ionization
The setting must be the same for every sample that need to be analysed later
The septum of each bag is punctured by the micro syringe and 2mm3 of gases is extracted from the bag and injected into the injection port of gas
Each of the gas is analysed and a calibration curve is obtained from the analysis
The tube and marbles that will be used for the experiment of cryogenic separation of CO2 from natural gas must be calibrated to ensure subsequent smooth operation, as well as to determine certain parameters that must be known during the experiment. For calibration, the apparatus must be used for cryogenic separation of CO2 from natural gas and the dimensions of the apparatus must be obtained. P.V.C tape is attached to the thread of the pipe to prevent leakage during the experiment.
The pipe is connected and the bottom of the pipe is closed with the cap. The volume of the pipe occupied by the stainless steel wool is marked on the pipe. Marble is inserted into the pipe and finally the stainless steel wool is inserted on top.
The tube to be used for the experiment with the cryogenic separation of C02 from natural gas must be calibrated to ensure smooth operation later and to determine certain parameters that must be known during the experiment. To determine the heat transfer coefficient across the pipe for the cryogenic separation of CO2 from natural gas experiment to better understand the pipe heat transfer. This is to create a vacuum space to reduce heat loss from the packed bed.
The valve at the liquid nitrogen Dewar opens slowly and liquid nitrogen is supplied into the packed bed. After the packed bed temperature reaches -50°C, the liquid nitrogen supply is stopped and the stopwatch is started. The temperature of the packed bed is measured every 10 seconds for 1 minute and every 1 minute after the first minute.
Due to the time limit as well as lack of suitable equipment, the experiment is done at atmospheric pressure. The flow of the liquid nitrogen is stopped after it reaches -110 °C and the C02 is fed to the packed bed. The sample is collected at the end of the column to be analyzed using the gas chromatograph (GC).
Superficial velocity, vg
Effective diffusion coefficient, Deff\
JXnjMft
Tci = Critical temperature of component i, TCOz = 304Kand TCH^ = 190.3 K
Putting allthe values into the diffusion coefficient equation to obtain Deff\
RePrXg Re2Pr2Ag
Peax 6(1-eg)Nu
This is shown by the straight line representing the same fraction of the CO2 as in the inlet. The graph shows that the shorter the time the feed gas is used in the packed bed, the smaller the change in temperature in the packed bed. However, the calibration curve obtained from the gas chromatograph is useful in quantitative analysis of the unknown sample.
The external standard is used in the quantitative analysis of the gas using a gas chromatograph. The fraction of an inch calculated here is the measure of the empty spaces in the packed bed. In addition, data on the characteristics of the packed bed is obtained and recorded for future use.
The result for experiment 3 is represented in the graph in figure 28 for the study of the heat loss to the surroundings of the system. T outside refers to the temperature probes located at the outer shell of the 4" pipe used as insulation for the cooled packed bed. As we can see from the graph, the temperature of the packed bed dropped rapidly just after the liquid nitrogen supply is stopped.
However, the temperature of the packed bed decreased slowly after the rapid decrease after 10 seconds. T2 refers to the thermometer probes located at the end of the packed bed farthest from the liquid nitrogen supply. T3 refers to the thermometer probes located in the center of the packed bed and T4 refers to the thermometer probes located in the 4" tube.
The graph shows the slow increase in the temperature of the packed bed after the C02 is supplied to the packed bed. This is due to the loss of "cold" or the transfer of heat from the higher temperature C02 to the very low temperature of the packed bed. As mentioned earlier, C02 is supplied on the other side of the packed bed which is closest.
The sample taken from the outlet of the packed bed was analyzed by gas chromatograph. The sample analysis is given in Table 5. However, for Case 2, the result shows that all the CO 2 is able to be captured by the packed bed.
