Abstract
Hydrate slurry has been reported to be a suitable secondary fluid for refrigeration and air-conditioning systems. The latent heat of CO2 hydrate is 387 kJ/kg under phase equilibrium condition of 7 °C and 30 bar. The utilization of CO2 hydrate slurry in air-conditioning systems is promising in improving the energy efficiency and shifting energy supply and demand load as well as relieving greenhouse effect caused by normal refrigerants like CFCs, HCFCs etc.
The production of CO2 hydrate slurry in a coil heat exchanger is investigated in this study. Crystals are supposed to firstly form on the wall of the tube, generating a solid layer. The appearance of the solid layer increases the heat resistance from liquid to the refrigerant. Type-III antifreeze proteins have been added to the solution to better control the crystallization process of hydrate formation since AFPs have proven to be an effective hydrate formation preventer which is environment friendly. A kinetic model is developed based on the gas hydrate growth model of Skovborg and Rusmussen (1994), taking the mass transfer process to be the rate-control step. The influence of pressure, temperature and concentration of the hydrate formation preventer on the diffusion coefficient of dissolved gas into the solid interface is investigated and mainly the concentration of hydrate formation preventer appears to have a large impact.
Results show that the growth rate decreases with the increase of the concentration of AFPs. Higher concentrations of AFPs move the equilibrium line to slightly higher temperatures.
The production of CO2 hydrate slurry in a coil heat exchanger is investigated in this study. Crystals are supposed to firstly form on the wall of the tube, generating a solid layer. The appearance of the solid layer increases the heat resistance from liquid to the refrigerant. Type-III antifreeze proteins have been added to the solution to better control the crystallization process of hydrate formation since AFPs have proven to be an effective hydrate formation preventer which is environment friendly. A kinetic model is developed based on the gas hydrate growth model of Skovborg and Rusmussen (1994), taking the mass transfer process to be the rate-control step. The influence of pressure, temperature and concentration of the hydrate formation preventer on the diffusion coefficient of dissolved gas into the solid interface is investigated and mainly the concentration of hydrate formation preventer appears to have a large impact.
Results show that the growth rate decreases with the increase of the concentration of AFPs. Higher concentrations of AFPs move the equilibrium line to slightly higher temperatures.
Original language | English |
---|---|
Title of host publication | Proceedings of the 16th International Refrigeration and Air Conditioning Conference at Purdue |
Subtitle of host publication | IRACC 2016 |
Editors | Eckhard Groll |
Place of Publication | West Lafayette, IN, USA |
Publisher | Purdue University |
Number of pages | 10 |
ISBN (Print) | 978-1-5108-2873-5 |
Publication status | Published - 2016 |
Event | 16th International Refrigeration and Air Conditioning Conference at Purdue - West Lafayette, IN, United States Duration: 11 Jul 2016 → 14 Jul 2016 Conference number: 16 |
Publication series
Name | Purdue e-Pubs |
---|---|
Publisher | Purdue University Libraries |
Conference
Conference | 16th International Refrigeration and Air Conditioning Conference at Purdue |
---|---|
Abbreviated title | IRACC 2016 |
Country/Territory | United States |
City | West Lafayette, IN |
Period | 11/07/16 → 14/07/16 |
Bibliographical note
Paper no. 1672http://docs.lib.purdue.edu/iracc/1672
Keywords
- hydrate slurry
- crystallization
- kinetic model