CAD programming: Spatial modeling of a column apparatus in the Autodesk Inventor environment

The tutorial describes in detail the creation of an external subsystem for Autodesk Inventor in the high-level language C# Microsoft Visual Studio of the column apparatus. Such issues as working in the Microsoft Visual Studio 2010 programming environment, connecting the library of functions of the Autodesk Inventor API to an external user subsystem, spatial solid-state modeling of elements of a column apparatus, saving constructed objects, assembling the apparatus from stored modules by the interface method of surfaces are considered. Meets the requirements of the federal state educational standards of higher education of the latest generation. For students of higher educational institutions studying in the direction of "Computer Science and computer engineering", in preparation for laboratory work and the exam. It can be used by students of other specialties when studying the courses "Fundamentals of Computer Science", "High-level programming language" and "3D modeling of machines and apparatuses". It may be useful for programmers engaged in spatial modeling of objects.

DETERMINATION OF HYDRODYNAMIC CHARACTERISTICS OF MASS-EXCHANGE COLUMN APPARATUS OPERATION IN A CYCLIC MODE

The efficiency of operation of perforated trays in a cyclic mode depends on the accepted hydrodynamic modes, which determine the limits of stable operation of mass-exchange column apparatus. There are no general methods of calculating the boundaries of the hydrodynamic modes of perforated trays operate in the cyclic mode. On this basis, the authors were tasked to determine the hydrodynamic modes of operation of mass-exchange column apparatus equipped with perforated trays, the action of which occurs in the mode of controlled cycles of fluid retention on the plates and the overflow of fluid through all holes or slits. Sieve and scaly trays with arched-type scales without overflow devices were selected for study. The aim of the work was to determine the hydrodynamic modes of operation of the sieve and scaly trays without overflow devices in a cyclic mode of retention and overflow of liquid, determination of lower and upper critical velocity of the vapor in the holes of the sieve and scaly trays, the linear velocity of the vapor in the free cross section of the mass-exchange column apparatus and the relative magnitude of the liquid splash to the upper trays. Liquid flow was monitored using a flowmeter RM, air velocity in the free section of the column was monitored using an anemometer MC-13. It was determined that the lower critical air velocity in the bubbling holes was 5.4 m/s; linear air velocity in free column cross section was 0.25 m/s. The velocity of the air in the holes at which the fluid splashes onto the upper plates begins was 8 m/s; thus linear air velocity in free column cross section was equal to 0.7 m/s. Hydrodynamic modes of scaly trays and corresponding values of air velocity in the free section of the column were established. In bubbling mode it was 0.5…0.9 m/s, in the transitional mode it was 0.9…1.3 m/s and in the jet mode, it was 1.3…2.0 m/s. It was determined that the lower critical air velocity in the holes of the trays, below which the drain of liquid is occurs, was 6.5…7.0 m/s. The upper critical air velocity in the holes of the trays above which the liquid splash on the upper trays is observed was 16 m/s. The air velocity in the free cross section of the column was 1.3…1.5 m/s. the relative magnitude of the liquid splash in the mode of steady operation of scaly trays in the bubbling mode does not exceed 0.1 kg/kg of air, in the jet mode, does not exceed 0.2 kg/kg of air. It is proved that intense overflow of liquid through bubbling holes of the perforated trays occurs at air velocities less than the lower critical. For sieve and scaly trays, this velocity should not exceed 1.5-1 m/s. A slight spillage of liquid through the holes of the trays occurs in the range of values of air velocity in the holes of sieve trays of 1.5-5.3 m/s, in the holes of scaly trays of 1,5-6,4 m/s.

IMPROVEMENT OF BIOGAS UPGRADING PROCESS USING CHEMICAL ABSORPTION AT AMBIENT CONDITIONS

Biogas major components are methane, carbon dioxide and traces of hydrogen sulfide, ammonia and nitrogen. Biogas upgrading process is the process by which carbon dioxide (composing 40 % of the biogas) is removed. In this study chemical absorption process using three different solvents (10 – 30 % monoethanolamine, 4 – 12 % sodium hydroxide and 5 – 15 % aqueous ammonia) was performed to produce methane-enriched biogas. A laboratory-scale packed-column apparatus containing efficient and cheap packing material (plastic bioball) was used to perform the experimental work in this study. Initial absorption runs were performed to select the best solvent type and concentration. Monoethanolamine (MEA) was proven to have the highest ability in producing upgraded biogas using a single absorption column apparatus at ambient conditions. The liquid to gas flow ratio was investigated using 30 % MEA solution. Optimum liquid to gas flow ratio for biogas upgrading process was determined to be about 18 (on mass basis). Biogas with methane content up to 96.1 v/v% was produced with CO2 loading capacity up to 0.24 mole-CO2 per mole-MEA.