Wyniki wyszukiwania - BazTech

1

Supercritical antisolvent method for recrystallization of HMX

Thakur Anupama, Taniya, Soni Pramod, Seema Mahesh, Deshwal Seema

Chemical and Process Engineering

|

2022

|

Vol. 43, nr 2

165--170

EN

Supercritical antisolvent (SAS) method is an emerging technique for particle processing of high energetic materials. The study investigates the recrystallization of high energy material HMX (octahydro- 1,3,5,7-tetranitro-1,3,5,7-tetrazocine) using SAS method. The effect of pressure, solution flow rate, supercritical antisolvent flow rate and temperature on particle size and morphology of HMX crystals has been studied with acetone as solvent and supercritical carbon dioxide as antisolvent. Stable and desirable 𝛽- polymorphic form of HMX could be obtained under certain process conditions and has been confirmed by FTIR spectroscopy. The experimental results show that 𝛽- polymorph of HMX is of rhombohedral morphology with mean particle size of 13.7 μm, as confirmed by SEM and particle size analyzer respectively.

2

Working Fluid Selection for Simple and Recuperative Organic Rankine Cycle Operating Under Varying Conditions: A Comparative Analysis

Igbong Dodeye, Nyong Oku E., Enyia James, Agba Ambrose

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no 4

202--221

EN

The selection of suitable working fluid for simple and recuperative organic Rankine cycle (ORC) operating under subcritical, superheated and supercritical conditions are investigated. 11 fluids with critical temperature above 1500C are considered as potential candidates. Performance screening parameters such as net power output, thermal efficiency, turbine sizing parameter (SP) and volumetric flow ratio (VFR), exegetic parameters like irreversibility rate, fuel depletion ratio, and improvement potential rate of exergy destruction were also evaluated. Results indicate that R600a, R236fa and R1233dz(E) demonstrated the best performance for subcritical, superheated and supercritical simple ORC, respectively. R236fa and R1233dz(E) proved more suitable for subcritical/superheated and supercritical recuperative cycles, respectively. The system exegetic efficiency is reveal to be significantly higher in subcritical/superheated (61-65%) cycles compared to the supercritical (35-45%) cycle, the evaporator seen as the main source of exergy destruction, accounting for 17-37% of inlet exergy destroyed and about 8-24% in the turbine.

3

Technologie mikrokapsułkowania – nowe trendy

Kawka D., Dłużewska E., Maszewska M.

Przemysł Spożywczy

|

2018

|

T. 72, nr 4

24--27

PL

W artykule przedstawiono kierunki rozwoju technologii mikrokapsułkowania składników i dodatków do żywności. Omówiono wyniki badań nad doborem właściwego nośnika, poprawą stabilności substancji aktywnych i wydajności procesów oraz nad modyfikacją sposobu uwalniania substancji aktywnych z mikrokapsułek. Przedstawiono nowości dotyczące m.in. suszenia rozpyłowego, mrożenia rozpyłowego, cyklodekstryn, liposomów. Zaprezentowano nowe technologie mikrokapsułkowania ze szczególnym uwzględnieniem tych metod, w których wykorzystuje się gazy w stanie nadkrytycznym. Technologie te pozwalają nie tylko na uzyskanie mikrokapsułek o lepszej jakości niż mikrokapsułki otrzymane metodami konwencjonalnymi, ale zaliczane są także do tzw. zielonych technologii, które umożliwiają większą ochronę środowiska.

EN

The article presents trends in technologies of microencapsulation of food ingredients and additives. The results of research on the choice of the proper carrier, the improvement of the stability of active substances and the efficiency of processes as well as on the modification of the method of release of active substances from microcapsules are shown. Also novelties concerning, among others, spray drying, spray freeze drying, cyclodextrins, liposomes are presented. New technologies of microencapsulation are described, with particular emphasis on those methods in which supercritical fluids are used. These technologies allow not only obtaining microcapsules with a better quality compared to microcapsules obtained by conventional methods, but also belonging to the so-called green technologies that allow for greater environmental protection.

4

High pressure vapour-liquid equilibrium of volatiles in supercritical carbon dioxide

Gurgenova K., Bogeł-Łukasik R., Wawrzyniak P.

Chemical and Process Engineering

|

2013

|

Vol. 34, nr 3

387--392

EN

Binary vapour-liquid equilibrium of thymoquinone and carbon dioxide at the isothermal conditions was carried out at temperature 323.15 K and pressures from 6 to 10 MPa. The experimental data were fitted to the Soave-Redlich-Kwong equation of state. Results could be used for selection of process parameters in separation of volatiles from raw oil or for evaluation of existing separation technologies.