Two-stage Cleaning Research Articles

Prospects for reducing resistance of ash collecting apparatus

Various variations of reducing the aerodynamic resistance of devices with a complex flow-through configuration are considered. About 50% of power plants in the Russian Federation operate on coal, with two-stage cleaning used in the ash collection process. Modern coarse ash collectors allow achieving an efficiency of 55 – 80% depending on their service life. It is advisable to reduce the number of cleaning stages by upgrading them with modern cleaning devices that allow achieving high efficiency of cleaning the dusty flow and subjecting this cleaning complex to less repair work. IVACis an inertial-vacuum ash collector, which can achieve the capture of a wide range of studied particles (1 – 100 μm) with an efficiency of up to 99%. This device was tested at the Omsk CHP Plant, but it was found to feature an increased aerodynamic resistance, as well as high efficiency. The objective of this work is to keep an aerodynamic resistance to 660 Pa (the resistance of the cyclone apparatus so that the apparatus can be used as the first and, consequently, as two stages of purification) while maintaining the efficiency of the apparatus. The results of changing the configuration of the flow part of the IVAC are analyzed, the model submitted for patenting after numerous is considered. The research methodology is the analysis of a numerical experiment in ANSYS CFX using the k-ε mathematical model (ash mass content of 70 g / kg; One-Way Coupling). In conclusion, recommendations are proposed for further prospects of IVAC research.

Obtaining higher manganese silicide films with high thermoelectric properties

This article provides information about the process of obtaining a Mn4Si7 film by magnetron sputtering, its high thermoelectric properties, and the possibility of using the resulting film in instrument-making production. Using the magnetron sputtering method, a thin Mn4Si7 film was obtained, and the composition and structure were studied by a scanning electron microscope. Two-stage cleaning of the silicon surface was used in work. Resistivity was determined by the four-probe method, thermoelectric properties, by the two-probe method. The bandwidth of the Mn4Si7/SiO2 film was measured on a high-precision spectrometer according to the law of light reflection. It is shown that the thermoelectric power of the Mn4Si7 film increases during the transition from the amorphous state to the nanocrystalline one, which is associated with the selective scattering of charge carriers at the boundaries of nanoclusters and Mn4Si7 on SiO2/Si have high speed and high sensitivity. It is shown that this film can be used in thermal detectors radiation waves in the visible and IR ranges.

Highly Efficient Treatment of Oily Sludge by a Novel High-Speed Stirring Method at Room Temperature.

Oily sludge is one of the main hazardous wastes which seriously endangers the ecological environment and human health. In this paper, in order to effectively treat oily sludge, a novel high-speed stirring (HSS) method was proposed to clean oily sludge, and the main parameters affecting the residual oil rate of oily sludge were studied experimentally. Firstly, the cleaning time and stirring speed were optimized in the one-stage HSS cleaning, and then the optimal cleaning time of two-stage HSS cleaning was determined by the response surface method. The results suggested that the oil can be efficiently separated by high-speed stirring at room temperature, and that the two-stage cleaning with a circular-hole outlet (Rotor-C) followed by a vertical hole-outlet (Rotor-V) presented the best effect. The optimal stirring speed was 6000 r/min, and the optimal cleaning times of the two-stage cleaning were 7 min and 8 min, respectively. After cleaning, the residual oil rate of the treated oily sludge was 1.65%, and the removal rate of the petroleum hydrocarbons was 84.3%.

Modernization of inertial-vacuum ash collector

Various variations of reducing the aerodynamic resistance of devices with a complex configuration of the flow path are considered. About 50% of power plants in the Russian Federation operate on coal, while two-stage cleaning is used in the ash collection process. Modern coarse ash collectors can achieve an efficiency of 55 – 80%, depending on the period of their work. It is advisable to reduce the number of purification stages by upgrading with the use of modern cleaning devices, which allow achieving high efficiency in cleaning a dusty flow and less subjecting this treatment complex to repair work. The inertial-vacuum ash collector (IVAC) provides trapping of a wide range of studied particles (1 – 100 microns) with an efficiency of up to 99%. This device was tested at the combined heat and power plant of the city of Omsk, and in addition to high efficiency, increased aerodynamic resistance was established. The aim of this work was to achieve an aerodynamic resistance of 660 Pa (resistance of the cyclone apparatus, so that the apparatus can be used as the first, and consequently as two stages of cleaning) while maintaining the efficiency of the apparatus. To achieve this goal, the IVAC uses the method of perforating holes along the divider for the subsequent decrease in speed in the confuser channel and a general decrease in resistance on the device. Perforation is carried out at three different heights, the distance between which is 1 meter. The study used the analysis of a numerical experiment in ANSYS CFX using a k-ε mathematical model (mass ash content 70 g/kg; One-way Coupling). Recommendations for further prospects for the study of the IVAC are proposed.

Innovation comprehensive solutions for off-gases cleaning in steel industry. Technical solutions for dusty gas flows cleaning

Metallurgical production associates with such processes as crushing, drying and pneumatic transportation of raw materials, roasting, melting etc., in the process of which hard particles and harmful gaseous components are emitted into atmosphere. At pneumatic transportation of raw materials and sand, their concentration in the atmosphere as a rule exceeds maximum permissible concentrations. Existing facilities of dusty flows cleaning in some cases don’t ensure sanitary norms ГН 2.1.6.3492‒17. Technical solutions proposed to clean gases in a centrifugal filter, a facility of complex gas cleaning – cyclo-filter and two-stage system of high-concentrated gas-dust flows cleaning. Description of the centrifugal filter, cyclo-filter, two-stage facility of gas cleaning design presented. The facility comprises centrifugal filter and ceramic pulse filter. Industrial tests of the centrifugal filter ЦФ2-6-1 under conditions of a system of pneumatic transportation of sand established, that efficiency of gas-dust flows cleaning of sand particles in a six-channel filter can reach 98.65%. Application of two-stage system of gas cleaning comprising centrifugal filter and ceramic pulse filter ФКИ enables to reach residual hard particles concentration at the exit of such a facility of 5 mg/m3, having initial dust level of 127878 mg/m3. Application of such a complex two-stage cleaning facility allows to reach values of 0.1 of maximum permissible concentrations near the source of emissions.

Selection of Expedient Combination of Charge Densities of Filters for Multistage Filtration of Spinning Solutions

An approach to expedient selection of charge density of filter baffle plates for two-stage cleaning of spinning solution of viscose and other solutions of polymers is scrutinized. Use of the characteristics of variation of unit costs per unit volume of the filtered spinning solution as a function of charge density of the main filtration stage as a criterion of selection is validated. Because of universality of the used generalized equation of filtration and economic criterion (unit cost) for analysis and selection of solution of the set task, the elucidated approach to finding the expedient combination of charge density for multistage filtration has prospect for use in industrial production of viscose and other artificial fibers, yarns, and films. This approach could be useful also for other industries that use filtering equipment.

Numerical and experimental studies of gas cleaning in multi-cyclone elements with filter inserts

As a result of the tightening of standards for the content of suspended particles with a particle size of less than 10 μm in the atmospheric air, the development of production structures in the urban environment often becomes closely linked to the problem of deep cleaning of heterogeneous emissions, that requires, at a minimum, two-stage cleaning. In this paper, we consider the effectiveness of using a multi-cyclone apparatus for such purposes, the elements of which combine both stages of purification. A bench test of such an element, which is a cyclone filter with a diameter of 250 mm on the basis of a serial cyclone TsN-11, was carried out. A numerical model of the multi-cyclone has been investigated, which has made it possible to establish the optimal arrangement of the cyclone elements with respect to the trajectories of the streams of trapped particles.

Measurements of ash emissions from a plant for burning of radioactively contaminated wood

The object of research is the efficiency of dust and gas treatment equipment for the removal of contaminated combustion products from the flue gases of the incinerator plant. One of the most problematic areas of the research facility is that when removing contaminated combustion products (ash) from flue gases, the efficiency of the dust and gas treatment equipment should ensure ash concentrations of up to 4 mg/m3 in the incinerator plant emissions.Investigations were conducted in Chornobyl, Ukraine on an incinerator plant equipped with a gas stream cleaning system, and includes coarse and fine cleaning. Application of two-stage cleaning allows to increase the efficiency of dust and gas cleaning equipment and to reduce emissions of radiation ash.In order to confirm the design requirement for gas cleaning equipment, in which flue gas filtration should provide ash emissions to 4 mg/m3, experimental measurements are made during the operation of the incinerator plant. Based on the results of measurements of dust and gas cleaning equipment, the maximum ash concentration is 3.76 mg/nm3, which meets the requirements.This plant plays an important role in reducing emissions and reducing the ecological load of the region and improving the environmental safety of Ukraine.

Gas emission monitoring of pre-heat furnace of metatitanic acid pastes

Due to the gradual convergence of national environmental legislation with European Union requirements it is necessary to conduct environmental monitoring of gas emissions of pre-heat furnace of metatitanic acid pastes. Critically analyzing the current system of clearing, it is established that technology isn’t provide the use of exhaust gas heat. As a result is an irreversible loss of 27,8 MW of heat and thermal pollution of the atmosphere; degree of purification of harmful components doesn’t exceed 55 %, which doesn’t meet modern requirements, then – a significant excess of maximum permissible concentrations of pollutants; insufficient level of dust collection, which causes loss of pigment TiO2. Overall, the current technology is ineffective and has no prospects for intensification.In the article the technological feasibility and economic viability of recycling waste and reducing energy consumption is proved. The concept of two-stage wet cleaning is proposed. Its implementation provides high separation efficiency of TiO2 particles, neutralization of harmful gas components and partial recycling of exhaust gas heat.

Analysis of dust removal equipment used in the manufacture of soluble powders

Analyzed the system of drying plant air cleaning, specializing in the production of food powders, dust emission identified place in the shop drying in the production of soluble dietary powders, the parameters of the dryer exhaust coolant, analyzed the properties of the product, as well as determined the effectiveness of the use of air purification equipment. Analyzed used at the enterprise two-stage cleaning system. As a first purification stage conical cyclone installed as a second stage purification analyzed dust collector is proposed with internal circulation of the liquid. It was found that the drying of the powder contained in the emissions of a large proportion of the fine fraction of dust. Several studies have been conducted with this food dust. It was found that the collection efficiency in the cyclone ranged from 68% (tea dust) to 92% (dust kvass wort). Analyzing the data obtained indicated that the efficiency of cleaning exhaust coolant is heavily dependent on the food composition of disperse dust, and less than 10 microns particles is insufficient. It is proposed to use for cleaning the coolant wet dust collector with internal circulation of the liquid. The regularities of change of concentration of solids in the cleaning liquid, its viscosity and surface tension with increasing operating time since the start of the dust collector. It is found that increasing the concentration of solids in the cleaning liquid increases with the operating time of the machine since the start-up leads to changes in surface tension and viscosity of the liquid. It is shown that the effective dust collection in the machine decreases as the viscosity of the working fluid. Both theoretically and experimentally established patterns may be used when calculating the optimum specific liquid flow to provide effective cleaning and releases the trapped product return process cycle.

PERFECTION OF PRINCIPLES FOR NATURAL GAS CLEANING FROM SOLID PARTICLES ON THE BASE OF TWO-STAGE MULTIBANK FILTERS WITH ONE-SIDE CONNECTION OF INLET AND OUTLET PIECES

Existing two-stage plants of natural gas cleaning, placed in front of safety protecting accessories and gas flow meter assemblies of main gas regulating modules are characterized by high metal consumption, considerable areas for their accommodation, large quantity of connecting elements and shut-off valves. Technical solution is offered for installation of two-stage cleaning, permitting at the same time to carry out natural gas rough and fine cleaning from solid, arranging two units of rough cleaning, connected in series, in one casing. The sizes of particles for rough cleaning should be not more than 0,1 mm and not more than 0,01mm for dust. Application of proposed multi-bank devices for complex natural gas cleaning from solid, liquid, and viscous particles with one-sided inlet and outlet pieces, arranged on the first cover, also permits, comparing with existing analogues to exclude laborious operations for disconnecting of the inlet and outlet pieces with feeding and leading off gas pipeline during dismantling, diminish the square and the volume of the space for gas regulating module, intended for proposed multi-bank cleaning plants, increase duration of the period between operations for moving off solid particles out of the filter, and provide the possibility for flexible increase of filter capacity during the reconstruction period owing to filter units quantity augment.

Research on Separation of Mixed Copper-Lead Concentrate

This paper presented the results of an investigation into effects of reagent removal by activated carbon, regrinding and combined depressant on the separation of chalcopyrite and galena. With the utilization of a selective collector called Z-200, a separation test of mixed copper-lead concentrate was conducted. By adopting single-stage roughing, two-stage scavenging, two-stage cleaning, a copper concentrate of containing 21.72% Cu, 7.81% Pb with the copper recovery of 91.28%, and a lead concentrate of containing 62.16% Pb, 0.82% Cu with the lead recovery of 95.24% were obtained.

Study on Flotation of Lead-Zinc Oxide Ore from Yunnan

With regard to a deep-extend oxidized refractory lead-zinc ore from Yunnan province, containing 4.55% Pb and 17.09% Zn, a test study was carried out. By adopting single-stage roughing, single-stage scavenging, two-stage cleaning in the flotation of lead oxide ores, and single-stage cleaning, single-stage cleaning in the reverse flotation of zinc oxide ores, bulk concentrate of lead and zinc containing 36.60% Pb, 19.63% Zn with the Pb recovery of 82.45%, zinc concentrate containing 36.52% Zn, 0.44%Pb with the Zn recovery of 73.18% were obtained in the closed circuit experiment.

Art Forms in Nature EXAMINATION AND CONSERVATION OF A BLASCHKA GLASS MODEL OF THE PROTOZOAN AULOSPHAERA ELEGANTISSIMA

The paper describes the examination and conservation treatment of a glass model of a micro-organism made by the German glass artisans Leopold and Rudolf Blaschka in the late nineteenth century. The beautiful object is part of a collection held at the Natural History Museum in London and has been chosen for priority conservation due to its relatively poor condition. The model is assembled from several hundred parts with the help of organic materials. Major conservation issues identified were breakages and detachments of extremely fragile glass spines, the partially unstable glass composition and consequent deterioration, the presence of a water-soluble organic coating and inappropriate previous storage conditions. Characterization of the original materials and their deterioration processes was carried out using a range of analytical facilities, allowing the development of suitable treatments. These included a two-stage cleaning process, reattachment of broken spines with Paraloid™ B72 and reversible remounting of fragments using nylon micro-tubing.

DESIGN AND DEVELOPMENT OF A THRESHING CHAMBER AND PNEUMATIC CONVEYING AND CLEANING UNITS FOR SOYBEAN HARVESTING

A threshing chamber was developed for an alternative soybean threshing device. Pneumatic conveying andcleaning systems were developed for the device based on dilute-phase design principles. Also presented is a structuredapproach for using dilute-phase pneumatic design principles to solve conveying and cleaning problems associated withsoybean harvesting. The device threshed standing uncut soybean plants with an array of plastic fingers fixed tocounter-rotating shafts. The threshed materials were initially pneumatically cleaned and then pneumatically conveyed to agrain tank. The collection system captured 85% of the threshed beans. A two-stage cleaning system was incorporated toremove the material-other-than-grain (MOG) before the grain reached the grain tank. Over 95% of the MOG, excludingsoybean stalks, was removed in the first stage of the cleaning system. The second stage of the cleaning system further removedthe chaff from the grain. The average efficiency of the conveying system was 92%.

Membrane Cleaning: Chemically Enhanced Removal of Deposits Formed During Yeast Cell Harvesting

Cleaning strategies have been evaluated for a microfiltration membrane fouled during cell harvesting. The membrane selected was a flat sheet of hydrophilic polyethersulphone with a nominal pore size of 0.1 μm. Baker’ s yeast was selected as a model micro-organism. During microfiltration, a constant transmembrane pressure of 2 bar, cross-flow velocity of 1ms−1, and suspension temperature of 34°C produced a steady state flux within 90 minutes. A water rinse removed the majority of the cellular cake revealing tenacious non-cellular and cellular deposits. Chemically enhanced cleaning of the rinsed deposit was investigated using dilute solutions of sodium hydroxide, nitric acid and P3 Ultrasil 11. Cleaning temperature effects were investigated over the range 30°C to 60°C and laminar and turbulent flow regimes were compared. A combination of measured flux recovery and microscopic visualization was used to assess cleaning performance. Effective two-stage cleaning was achieved with sequential alkali and acid treatments while effective single-stage cleaning was achieved using the formulated detergent P3 Ultrasil 11.

Flotation of Rakha (India) copper ore with LIX-65 NS

Copper ore from the Rakha Copper Concentrator (India) was successfully floated using LIX-65 NS as the collector. The beneficial role of this reagent was clearly demonstrated in hatch-flotation tests. From a feed containing around 1% Cu, it was possible in a single-stage flotation to obtain a 23.7% Cu concentrate with a recovery of more than 90%. The plant now uses rougher, scavenger and a two-stage cleaning process. The tests demonstrated that LIX-65 NS is superior to conventional xanthate for the recovery of copper from the Rakha ore.

Disinfection of food production areas.

Disinfection, other than by heat, is ineffective unless all surfaces have previously been thoroughly cleaned to remove interfering materials. Cleaning is therefore extremely important as part of a two-stage cleaning and disinfection (sanitation) programme. The author describes the principles of sanitation, the chemicals and equipment involved, and the programme of events to be followed. For food products of 'low risk' (in terms of stable shelf life and safety), traditional sanitation programmes are adequate and in some cases disinfection may not be required. However, disinfection is essential for 'high-risk' food products, but this cannot be effectively undertaken without due consideration of hygienic design and possible cross-contamination. To ensure continued satisfactory performance of a sanitation programme, routine assessments should be undertaken.