3 research outputs found
N‑Containing 1,7-Octadiyne Derivatives for Living Cyclopolymerization Using Grubbs Catalysts
Synthesis
of a new class of conjugated polyenes containing N-heterocyclic six-membered
rings was demonstrated via cyclopolymerization of N-containing 1,7-octadiyne
derivatives using Grubbs catalysts. Successful cyclopolymerization
was achieved by introducing protecting groups to the amines in the
monomers. Moreover, a hydrazide-type monomer containing a di-<i>tert</i>-butyloxycarbonyl group (<b>6</b>) promoted the
living cyclopolymerization to give polyÂ(<b>6</b>) with a controlled
molecular weight and narrow dispersity. This living polymerization
allowed us to prepare various conjugated diblock copolymers using
polyÂ(<b>6</b>) as the first block
CFD Simulation of Microchannel Reactor Block for Fischer–Tropsch Synthesis: Effect of Coolant Type and Wall Boiling Condition on Reactor Temperature
Computational
fluid dynamic (CFD) simulation of heat transfer in
a microchannel reactor block for low temperature Fischer–Tropsch
(FT) synthesis was considered. Heat generation profiles for different
operating conditions (GHSV 5000 h<sup>–1</sup>; catalyst loading
60%–120%, where 100% loading equals 1060 kg/m<sup>3</sup> of
cobalt based catalyst from Oxford Catalyst Ltd.) were obtained from
a single channel model. Simulations on a reactor block quantified
the effects of three coolant types: cooling oil (Merlotherm SH), subcooled
water and saturated water, on reactor temperature, and also evaluated
the effect of wall boiling conditions. At process conditions of GHSV
5000 h<sup>–1</sup> and catalyst loading of 120%, predicted
temperature gradients along channel length were 32, 17 and 12 K for
cooling oil, subcooled water and saturated water, respectively. A
modified reactor block showed improved thermal performance as well
as heat transfer enhancement due to wall boiling conditions
Computational Fluid Dynamics Based Optimal Design of Guiding Channel Geometry in U‑Type Coolant Layer Manifold of Large-Scale Microchannel Fischer–Tropsch Reactor
A microchannel Fischer–Tropsch
reactor retaining high heat
and mass transfer performance requires uniform flow distribution on
the coolant side to induce isothermal condition for controllable and
sustainable operation. The present work improved the flow performance
of a large-scale layer of over 100 channels by introducing an extremely
simple guiding fin in the inlet and outlet rectangular manifolds.
Case studies with three-dimensional computational fluid dynamics (CFD)
were carried out where the upper and bottom lengths of the guiding
fin were the main geometric variables. Then the optimization work
was conducted to estimate the performance of the optimal design. The
robustness for the proposed geometry was tested with varying the flow
rate, fluid type, and temperature. The result showed that the proposed
design can retain uniform distribution over a wide operation range
(500 ≤ <i>Re</i><sub>GF</sub> ≤ 10800)