INTEGRATED CRYOGENIC SYSTEM FOR CO[sub 2] SEPARATION AND LNG PRODUCTION FROM LANDFILL GAS

Abstract

An integrated cryogenic system to separate carbon dioxide (CO 2 ) and produce LNG from landfill gas is investigated and designed. The main objective of this design is to eliminate the requirement of a standard CO 2 removal process in the liquefaction system such distillation or (temperature or pressure) swing adsorption, and to directly separate carbon dioxide as frost at the liquefying channel of methane. Two identical sets of heat exchangers are installed in parallel and switched alternatively with a time period so that one is in separation-liquefaction mode while the other is in CO 2 clean-up mode. A thermal regeneration scheme is presented for the purpose of saving energy and avoiding the stoppage of LNG production followed by the flow switching. The switching period is determined from results of a combined heat and mass transfer analysis on the CO 2 freeze-out process.

Solid–Liquid–Vapor Equilibrium Models for Cryogenic Biogas Upgrading

“…For instance, Tuinier et al exploited a novel cryogenic capture process using dynamically operated packed beds, whereas Song et al and Chang et al developed two cryogenic separating systems able to capture the CO 2 for solidification in heat exchangers. The adopted refrigerating systems are a Stirling chiller and a Brayton refrigerator, respectively. In 2001, Clodic and Younes developed a cryogenic separation process, in which the CO 2 could be captured as a solid on the fins of heat exchangers which were cooled thanks to an integrated cascade system.…”

“…Researches in this field result in the development of different processes. For instance, Tuinier et al 3 exploited a novel cryogenic capture process using dynamically operated packed beds, whereas Song et al 4 and Chang et al 5 developed two cryogenic separating systems able to capture the CO 2 for solidification in heat exchangers. The adopted refrigerating systems are a Stirling chiller 4 and a Brayton refrigerator, 5 respectively.…”

Hydrate-based CO2 capture and CH4 purification from simulated biogas with synergic additives based on gas solvent

“…Therefore, separation of CO 2 from CH 4 is very important in these cases. Numerous ways can be applied to separate CO 2 and obtain purified CH 4 from biogas [4], such as water wash [9], absorption [10], adsorption [11], cryogenic fractionation [12], and membrane separation [13]. However, new processes should be considered due to the energy cost.…”

Thermodynamic Equilibrium Conditions for Simulated Landfill Gas Hydrate Formation in Aqueous Solutions of Additives

“…4 However, the removal of CO 2 from the landfill gas is very important in this case since it is the prerequisite process to enhance its calorific values and reduce the greenhouse effect. Numerous ways can achieve this goal, 5 such as absorption, 6,7 adsorption, 7 cryogenic fractionation, 8 and membrane separation. 9 These processes prove successful for the selective removal of CO 2 , but their major drawback is the large energy cost.…”