An absorption–hydration hybrid method was employed
for separating
C2 components (C2H4 + C2H6) from low-boiling gas mixtures such as refinery dry gas using water-in-diesel
emulsions under hydrate formation conditions. Span 20 was used to
disperse the water or hydrate in diesel to form the emulsion or hydrate
slurry. To simulate a three-stage separation process, three (CH4 + C2H4 + C2H6 + N2) feed gas mixture samples with different gas molar
compositions were prepared. Separation experiments were performed
under different conditions to investigate the influences of feed composition,
temperature, pressure, initial water cut in the emulsion, and initial
gas/liquid volume ratio on separation efficiency. The experimental
results show that the absorption–hydration hybrid method is
obviously superior to the single-absorption method. After three stages
of separation at appropriate operating conditions, we found that C2
compounds can be enriched from ∼15 to more than 50 mol % in
the (hydrate + diesel) slurry phase and that the content of C2 compounds
in the residual gas phase can be reduced to lower than 2 mol %. Low
temperature, low initial gas/liquid volume ratio, high pressure, and
high water cut were found to be favorable for the recovery of C2 compounds.
However, when the temperature was lower than 270.2 K and the water
cut was higher than 30 vol %, the formation of flowable hydrate slurry
became difficult.
Optimizing
interfacial compatibility is one of the core issues
for constructing high-performance green poly(lactic acid) (PLA) blends.
Herein, we prepared a poly(epichlorohydrin)-b-poly(d-lactic acid) (PECH-b-PDLA) diblock copolymer
as an efficient compatibilizer for poly(l-lactic acid)/poly(epichlorohydrin)
(PLLA/CHR) blends. The PECH-b-PDLA enabled the blends
to form unique interlocks among the chains through combining the strong
dipolar interaction and PLLA/PDLA stereocomplexation (SC). This strategy
endows the PLLA/CHR blend with a unique “co-continuous”
structure composed of CHR particles as the core and a bilayer shell
formed by the PECH entanglement layer with strong dipolar interaction
and a rigid SC thin layer. Physical properties of the blends were
remarkably improved by a co-continuous structure with enhanced interfacial
adhesion between phases. The optimum formulation showed unprecedented
balanced mechanical properties: a nonbroken sample with an impact
strength of 106.7 kJ/m2 and a high elongation at break
of up to 467.2%; both were about 40 times those of pure PLLA. The
interlocking mechanism through strong dipolar interaction and SC provides
a broadly applicable and facile strategy to achieve PLA materials
with superior properties for expanded industrial application.
Marine spherical double plugging is a novel plugging device, which can achieve the initiative plugging in the oil and gas pipeline. In order to ensure that the plugging head will not collide with the pipeline wall and not be scratched by the drill cuttings, the analysis of twisting process is necessary to assure reliable operation. In this article, we designed the overall scheme of marine spherical double plugging and established the mathematic model of spherical double plugging. Through studying the twisting algorithm of plugging head and trajectory algorithm of plugging head contour, four dangerous points were obtained. The multi-body dynamic of the structure was built using ADAMS, and the twisting process and motion analysis of four points were analyzed. The twisting error of the plugging head between the four points and the inner wall of the pipeline was analyzed in overshoot states to obtain the maximum allowable overshoot of inserting hydraulic cylinder and twisting hydraulic cylinder. Simulation results show that overshoot of inserting hydraulic cylinder needs to be controlled within 11.5 mm and overshoot of twisting hydraulic cylinder needs to be controlled within 5.3 mm to avoid the unpredictable danger. This article will provide theoretical and technical support for the optimization design of control system and the plugging head.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.