Moisture Separation Research Articles

The effect of moisture content on the energies involved in the compaction of ibuprofen

The influence of moisture content and compression speed on the ejection force, plastic and elastic energies of ibuprofen was measured. It was found that moisture can significantly reduce the force required to initiate ejection by the breaking of tablet/die-wall adhesions. At all compression speeds, an increase in moisture content resulted in a marked reduction in the ejection force of ibuprofen compacts. The plastic energy was found to increase with moisture content up to 2.5% w/w, ascribed to an increase in particle-particle interactions. Subsequent decrease in plastic energy at higher moisture contents was probably due to a decrease in particle interaction due to the moisture separation of the particles of ibuprofen. The elastic energy was found to decrease with increasing moisture content up to about 2.5% w/w. This is believed to be due to the strong bonding of particles, brought about by moisture facilitating the formation of interparticle hydrogen bonding and so reducing the interparticle separation. Subsequent increase of elastic energy with increasing amount of moisture beyond 2.5% w/w was thought to be due to the formation of multilayers of water at the surfaces of the particles. This excess moisture increased the elastic energy, by decreasing particle-particle interaction.

Steam Turbine Generators for Sizewell ‘B’ Nuclear Power Station

The thermodynamic cycle of the modern 3000 r/min steam turbine as applied at Sizewell ‘B’ is presented. Review is made of the factors affecting thermal efficiency including the special nature of the wet steam cycle and the use of moisture separation and steam reheating. Consideration is given to the optimization of the machine and cycle parameters, including particular attention to reheating and to the provision of feedheating, in order to achieve a high overall level of performance. A modular design approach has made available a family of machines suitable for the output range 600–1300 MW. The constructional features of the 630 MW Sizewell ‘B’ turbine generators from this range are described in detail. The importance of service experience with wet steam turbines and its influence on the design of modern turbines for pressurized water reactor (PWR) applications is discussed.

Horizontal-tube film desalination plants. Research data, of principal processes and of production prototypes design

The paper presents experimental data on the dynamics of a liquid film on the outer surface of a horizontal pipe as well as on heat transfer from vapour to the inner surface and from outer surface to a film of draining off liquid for smooth and diversely shaped horizontal pipes, on moisture separation and the design of a tube bundle and a feed distributor. The data were obtained from the tests of laboratory, rig and experimental-commercial horizontally arranged tube climbing film evaporators (HTPE). The data permitted the methods of HTFE calculation and four types of desalination units of the output from 10 to 700 t/h equipped with the above evaporators to be developed.

On investigation results of steam separation and heat transfer intensification in distillation desalination units of two types

The results are presented of the studies into the processes of moisture separation and heat-and-mass transfer in evaporators of distillation desalting units (DDU). Recommendations are given on the use of separation devices that ensure a high degree of vapour purification from drops entrained and the data are considered on the effectiveness of heat-and-mass transfer from condensing vapours on shaped pipes in case of pure vapours and vapours containing air. The possibility is shown of intensifying heat transfer from vapours by additionally shaping the surface of standard longitudinally shaped vertical pipes or by using horizontal shaped ones.

Horizontal-tube film desalination plants. Research data of principal processes and of production prototypes design

The paper presents experimental data on the dynamics of a liquid film on the outher surface of a horizontal pipe as well as on heat transfer from vapour to the inner surface and from outher surface to a film of draining off liquid for smooth and diversely shaped horizontal pipes, on moisture separation and the design of a tube bundle and a feed distributor. The data were obtained from the tests of laboratory, rig and experimental-commercial horizontally arranged tube climbing film evaporators (HTFE). The data permitted the methods of HTFE calculation and four types of desalination units of the output from 10 to 700 t/h equipped with the above evaporators to be developed.

The application of basalt paper and board as filtration materials for the purification and sterilization of air

Papers have appeared in recent years on the application of special types of paper and board for the sterilization of air by filtration [1-3]. The properties of these materials depend on many factors: the type of fibers used, methods of physicochemical treatment, the presence of sizing agents, etc. The structure of a sheet for air purification is that of a fairly porous interweaving of fibers of various lengths The most dependable method of preparing filter paper and board of uniform structure is the multilayer pouring method [4], since on superimposing thin leaves one upon the other, possible defects in individual layers are covered. Sterile air is used in the process of manufacturing antibiotics and is obtained by filtration through a layer of fibrous filtration material. Sterile air, which is supplied for aeration in the fermentation process, must have a defined temperature and moisture content. In the event of a drop in air temperature below the dew point, moisture separation occurs which wets the filtration material and leads to a reduction in its mechanical strength. Moreover, as a result of the swelling of cellulose fibers the pore size and consequently the air penetrability is reduced [4, 5]. To prevent the phenomenon mentioned and to impart hydrophobicity and ~-et strength to the paper and board, various polymeric binders are introduced into the fibrous mass which after special treatment confer stiffness on the paper fibers. The filtration materials obtained in this way are sufficiently tough, stable to the action of moisture, and retain their previous values of specimen porosity thus guaranteeing a high moisture penetrability. At the present time basalt superfine fiber (BSFF) (fiber diameter 1 p) is used as a filtration material in filters for the fine purification of air [6]. This material answers the requirements set for a material for sterilization by the filtration method, viz. a high effectiveness in retaining particles of contaminants (99.999 % of 0.3 p particles), sufficient vapor and thermal stability, and an extended service life. The comparatively small mechanical strength is a shortcoming of the material. This shortcoming also caused a search for a filtration material based on BSFF and more sturdy and convenient in operation. Specimens of materials in form of paper and board based on BSFF have been developed in the Ukrainian Paper Research Institute [7]. Pulverized cellulose fibers and latex were added to increase the durability of materials in manufacture. An investigation has been carried out in the All-Union Scientific-Resea rch Institute of Antibioties on specimens of basalt paper and board with the aim of possibly using them for the sterilization of process air in antibiotic manufacture. It is known that materials for air purification are evaluated according to the drop in pressure and the size retention of particles entering with the air [8]. An increase in the drop in pressure is energetically unprofitable; however, simultaneously with the growth of this parameter the efficiency of retaining particles is raised, and consequently it is necessary to find the size of the optimal ratio of the values mentioned. An investigation to find the optimum has been carried out with the aim of elucidating the interrelationshi p of the properties of the paper and the sizes of the characteristics mentioned. Tests on specimens of paper and board were carried out at afiltration rate ofl cm/sectaldng the highly effective materials for testing [9] The effectiveness of a material was verified on a test bed with an oil spray [I0]. Averaged results of several measurements are presented in Tables 1 and 2. In column 2 of Tables 1 and 2 the labelling of the basaltic materials submitted by the manufacturer is given. For example,