Low-temperature Filtration Research Articles

Effect of Nanoparticles on Rheological Properties of Water-Based Drilling Fluid.

Nano-water-based drilling fluids (NWBDFs) are prepared using nano-copper oxide (CuO) and multiwalled carbon nanotubes (MWCNTs) as modification materials. The effects of the temperature and concentration of the nanoparticles (NPs) on the rheological properties are studied using a rotational rheometer and viscometer. Also, the influence of two NPs on the filtration properties is studied using a low-pressure and low-temperature filtration apparatus, as well as a scanning electron microscope (SEM). It is found that MWCNTs with a concentration of 0.05 w/v% have the most obvious influence on the NWBDFs, which improve the stability of the gel structure against temperature and also decrease the filtration rate. Finally, a theoretical model predicating the yield point (YP) and the plastic viscosity (PV) as a function of the temperature considering the influence of the NPs is developed based on DLVO theory.

Generic and rapid determination of low molecular weight organic chemical contaminants in protein powder by using ultra-performance liquid chromatography-tandem mass spectrometry

A rapid, simple, and generic analytical method that could simultaneously determine 291 undesirable low molecular weight chemical contaminants from different drug families in protein powder, such as veterinary drugs and pesticides, etc, had been developed. This method comprised the extraction with acetonitrile-dimethyl sulfoxide (DMSO), clean-up through dispersive solid phase extraction (D-SPE) and low temperature filtration, and analysis by ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry at multiple-reaction monitoring mode. Acetonitrile-DMSO was more generic than acetonitrile or methanol for the extraction of large-scale organic chemical contaminants with different polarities in protein powder. Most interferences in the extract were eliminated by the combination of D-SPE and low temperature filtration, which simultaneously provided satisfactory recoveries of both hydrophobic and hydrophilic analytes. In particular, besides the purification function, the sorbent of D-SPE also played an important role in grinding samples to improve extraction efficiency during homogenization. This streamlined approach allowed the processes of extraction and the main purification were carried out in one-step, and dramatically reduced sample preparation turnaround times and solvent consumption. For quantification, matrix-fortified calibration curves showed competent linearity for most of the target compounds with linear regression coefficients (r) higher than 0.9900, except for two analytes. The limits of quantification ranged from 0.1 μg/kg to 50 μg/kg, which was usually sufficient to verify the compliance of products with legal tolerances. The average recoveries for spiked protein powder ranged from 65.6% to 142.2% with associated RSD values between 0.5% and 28.5%. For over 90% of the analytes, the recoveries were between 70% and 120% with RSD values in the range of 1%–15%. Applying this method in routine monitoring programs would drastically reduce both effort and time.

Trace Water Removal from Nitrous Oxide in a Membrane Cascade

A method is proposed for the removal of water vapor from commercial grade nitrous oxide during its high purification using membrane gas-separation technologies. A single membrane module, a two-stage recirculation unit with the recycling of permeate stream, and two-stage cascades with membranes of different selectivity and experimentally determined the permeability of Lestosil, PVTMS, and CTA test membranes to nitrous oxide have been considered. The optimum values of the main operating parameters of the drying system have been determined, and the energy efficiency of membrane gas separation and low-temperature filtration processes have been evaluated with taking into account the operating costs and purified gas losses.

Graphene nanoplatelets as high-performance filtration control material in water-based drilling fluids

The main objective of this work is to evaluate the effectiveness of graphene nanoplatelets (GNP) as filtration control materials in water based drilling fluids. Three (3) general samples of water based drilling fluids were prepared including basic potassium chloride (KCl) drilling fluids, nanosilica (NS) drilling fluids and GNP drilling fluids. Several concentrations of NS and GNP were dispersed in controlled formulations of water based drilling fluids. Standard API filtration tests were carried out for comparison purposes as well as High Temperature High Pressure (HTHP) filtration tests at 150 °F (∼66 °C), 250 °F (∼121 °C) and 350 °F (∼177 °C) at a fixed 500 (∼3.45MPa) psi to study the filtration trend as a function of temperature. Mud cake samples from several tests were selectively chosen and analyzed under Field Emission Scanning Electron Microscope (FESEM) for its morphology. Results from this work show that nanoparticle concentrations play a factor in filtration ability of colloid materials in water based drilling fluids when studied at elevated temperature. Low temperature filtration, however, shows only small differences in volume in all the drilling fluid samples. 0.1 ppb concentrations of GNP reduced the fluid loss of 350 °F by 4.6 mL as compared to the similar concentration of NS drilling fluids.

Asymptotic approximation of long-time solution for low-temperature filtration combustion

There is a renewed interest in using combustion for the recovery of medium viscosity oil. We consider the combustion process when air is injected into the porous medium containing some fuel and inert gas. Commonly the reaction rate is negligible at low temperatures, hence the possibility of oxygen breakthrough. In this case, the oxygen gets in contact with the fuel in the downstream zone leading to slow reaction. We focus on the case when the reaction is active for all temperatures, but heat losses are negligible. For a combustion model that includes heat and mass balance equations, we develop a method for calculating the wave profile in the form of an asymptotic expansion and derive its zero- and first-order approximations. This wave profile appears to be different from wave profiles analyzed in other papers, where only the reaction at the highest temperatures was taken into account. The combustion wave has a long decaying tail. This tail is hard to observe in the laboratory because heat losses must be very small for the long tail to form. Numerical simulations were performed in order to validate our asymptotic formulae

Water removal from ammonia by low-temperature filtration

This paper examines the removal of high-boiling, poorly soluble impurities from ammonia by low-temperature filtration using fine fiber filters. We describe a technique for evaluating low-temperature filtration parameters which takes advantage of the Lifshits-Slezov model and filtration theory, calculate parameters of water removal from ammonia, and experimentally verify the calculation results.

A design for low-temperature filtration of strongly hygroscopic crystals

A design for low-temperature filtration of strongly hygroscopic crystals

Initiation of low-temperature filtration combustion waves for porous systems

In this work a numerical modeling method was used to study different variations of realizing this method: local ignition in the central part of a porous specimen of "infinite" (from the point of view of its excluding the effect of boundary conditions) length; initiation of a counter FC wave by local warm-up of the rear (in relation to the direction of gas filtration) part of the specimen; formation of an associated inverse FC wave with warm-up of its frontal part. The aim of this study is to clarify the features of FC wave dynamics, the effect on it of temperature @p and width of the firing zone 6warm-up) Lp; to establish the relationship between the minimum (critical) ignition temperature @i and Lp with different regime parameters and characteristics of the physical system; to determine the ignition time Ti and the amount of "flashback" of the oxidant (instantaneous ~L/~0 and integral ~(~L/~0)e~ during firing, o

Effect of heat losses on propagation of stationary low-temperature filtration combustion waves with forced filtration of the gas-oxidizer

Effect of heat losses on propagation of stationary low-temperature filtration combustion waves with forced filtration of the gas-oxidizer

Low temperature filtration device and method for the purification of crude nitrogen trifluoride

Low temperature filtration device and method for the purification of crude nitrogen trifluoride