TY - JOUR

T1 - Dynamics of pressure- and temperature-initiated adsorption cycles for transformation of low temperature heat: Flat bed of loose grains

AU - Girnik, I. S.

AU - Okunev, B. N.

AU - Aristov, Yu I.

PY - 2020/1/25

Y1 - 2020/1/25

N2 - Despite significant progress made in adsorption heat transformation, still, there is a big room for it's further improving. This work addresses the dynamic study of methanol adsorption and comparison of two ways of the process initiation. The traditional way is due to fast temperature change (TI), and the less studied one is by quick pressure variation (PI). The appropriate temperature/pressure variations were selected similar to those in a new cycle “Heat from Cold” recently suggested for upgrading the ambient heat in cold countries. An activated carbon ACM-35.4, used as a methanol adsorbent, was located on metal support as a thin flat bed of loose grains. For a monolayer bed configuration, the dynamics is almost identical for the two initiation ways. Both TI and PI kinetic curves are exponential with a characteristic time, which depends on the process boundary conditions rather than the initiation mode. The mathematical model of methanol adsorption on a single spherical carbon grain is developed to explain these results. The perceptible difference is found for the multi-layer configuration of the carbon bed. The PI adsorption dynamics is faster than the TI one at short adsorption time and equal to it at long time. A possible reason for this difference is discussed.

AB - Despite significant progress made in adsorption heat transformation, still, there is a big room for it's further improving. This work addresses the dynamic study of methanol adsorption and comparison of two ways of the process initiation. The traditional way is due to fast temperature change (TI), and the less studied one is by quick pressure variation (PI). The appropriate temperature/pressure variations were selected similar to those in a new cycle “Heat from Cold” recently suggested for upgrading the ambient heat in cold countries. An activated carbon ACM-35.4, used as a methanol adsorbent, was located on metal support as a thin flat bed of loose grains. For a monolayer bed configuration, the dynamics is almost identical for the two initiation ways. Both TI and PI kinetic curves are exponential with a characteristic time, which depends on the process boundary conditions rather than the initiation mode. The mathematical model of methanol adsorption on a single spherical carbon grain is developed to explain these results. The perceptible difference is found for the multi-layer configuration of the carbon bed. The PI adsorption dynamics is faster than the TI one at short adsorption time and equal to it at long time. A possible reason for this difference is discussed.

KW - Activated carbon

KW - Adsorptive heat transformation

KW - Driving force

KW - Methanol

KW - PUMPS

KW - SORPTION

KW - ADSORBENT

KW - DRIVEN

KW - PAIRS

UR - http://www.scopus.com/inward/record.url?scp=85075357187&partnerID=8YFLogxK

U2 - 10.1016/j.applthermaleng.2019.114654

DO - 10.1016/j.applthermaleng.2019.114654

M3 - Article

AN - SCOPUS:85075357187

VL - 165

JO - Applied Thermal Engineering

JF - Applied Thermal Engineering

SN - 1359-4311

M1 - 114654

ER -