Reference no: EM132896438
MECH341 Fluid Mechanics - Queen’s University
Natural Gas Dehydration Assignment
Assignment type:
This is a team assignment to be done with a group of four members. There must be no collaboration between teams. Teams are the same as those for your air conditioning laboratory. It is your responsibility to start team meetings within the first week after assignment distribution.
Assignment task:
To produce pipeline quality dry natural gas, sourced gas must undergo processing to remove impurities. These impurities include water, carbon-dioxide and the heavier hydrocarbons (essentially reducing every component except the methane and ethane to trace amounts). Water must be removed at the wellhead to prevent the formation of methane hydrates within the gas processing plant and the gas transmission pipelines.
Usually the removal of water vapour from natural gas is performed using either absorption (e.g. glycol dehydration) or adsorption using a solid adsorbent (e.g. solid-desiccant dehydration). Heavier hydrocarbon compounds may then be removed using absorption while lighter hydrocarbons such as ethane require a cryogenic expansion process to extract a significant portion.
In the proposed processing plant, the reduction of the water content to an acceptable level is to be achieved by dehumidification using a mechanical refrigeration plant. Natural gas water content of less than 0.3% by weight will be considered an acceptable upper limit.
The composition, temperature and pressure of the natural gas supplied to the refrigeration plant near the wellhead will be provided through your group's Moodle discussion board.
You are to specify the requirements of the refrigeration system capable of reducing the water vapour content from the natural gas source to acceptable levels. As part of this process, you should:
• Find suitable phase and material property data for the constituent gases and the water vapour.
• Determine the properties of the gas-vapour mixture using suitable models.
• Derive psychrometric relationships for the gas-vapour mixture and create the associated psychrometric chart (the chart should include at least the wet and dry bulb temperatures, the specific and relative humidity, the mixture enthalpy and specific volume).
• Plot the water removal process on your psychrometric chart.
• Determine the necessary operational requirements of the refrigeration system:
o the minimum temperature of the natural gas required for the process,
o the heat to be removed per unit mass of natural gas, and
o a suitable refrigeration cycle and refrigerant.
• State all assumptions made and discuss the limitations and hence the usefulness of your modelling. When discussing the usefulness of your modelling results for a real-world application, you should also consider the following:
o How sensitive are your results to changes in the natural gas mixture component ratios? For example, what does a 5% change in Methane content (with corresponding changes in the other components) have on the refrigeration system requirements?
o How sensitive are your results to changes in wellhead temperature? - and pressure?
Your solution should be communicated in a short report. The report must be no more than six pages long. Appendices should not be used. In the interest of assessment equity between groups, anything beyond the permitted 6 pages for the written report will not be examined.
Attachment:- Fluid Mechanics.rar