This paper presents a study on the effect of cleaning factors on the energy consumption of the cleaning process in a CIP system, and the correlation between single components of electricity necessary to perform this process and the cleanliness degree obtained. Studies were carried out in a laboratory cleaning station, wherein a plate heat exchanger contaminated with hot milk was included. The research program was developed according to a 5-level statistical plan. Based on the results, obtained with Experiment Planner 1.0, a regression function of energy requirement considering variables such as: cleaning time, temperature and flow rate of the cleaning liquid via the cleaned exchanger has been developed. Describing this relationship, linear and quadratic functions with double interactions were used. Significance level for the analysis was established at α = 0.05. Correlation analysis between components of the electricity necessary to perform the cleaning process (pump drive and heating of the cleaning agent) and the resulting degree of cleaning of heat exchanger plates was performed.
A simple model of behaviour of a single particle on the bulging membrane was presented. As a result of numerical solution of a motion equation the influence of the amplitude and frequency of bulging as well as the particle size on particle behaviour, especially its downstream velocity was investigated. It was found that the bulging of a membrane may increase the mean velocity of a particle or reinforce its diffusive behaviour, dependeing on the permeation velocity. The obtained results may help to design new production methods of highly fouling-resistant membranes.
The aim of this work was to present the numerical simulation results determining the distributions of flow velocity and pressure in the individual channels of a plate heat exchanger. The simulations have been conducted by means of the Finite Volume Method (FVM) of numerical computation using the ANSYS CFX software. The computational model constituted spaces between 10 flat, straight flow type plates of the heat exchanger. The obtained results of numerical simulations confirm the presence of inhomogeneous flow conditions in the neighbouring channels between the plates. The computations enabled to point out the regions on the plates, in which insufficient flow can result in problems with their cleaning. The results of this work constitute the first part of a research leading to an assessment of cleaning conditions in plate heat exchangers.
At present, electromobility is a very dynamically developing segment and at the same time has many unknowns that enterprises that want to develop this area in their structures have to face. This article aims is to show the difficulties of electromobility development from the perspective of Polish energy groups which are closely related to this area, especially considering the obligations imposed on energy companies by the legislator. The electrification of transport has become a reality and in order to use its potential to develop new services or implement innovations and new technologies, it is necessary to identify development barriers and prepare a response plan. The authors of the article decided to show the formal and legal implications for the development of electromobility in Poland in first order, and then examine the development strategies of Polish energy groups in terms of electromobility and indicate explored areas related to it. The next section focuses on identifying the main barriers to the implementation of business models, classifying them according to the following factors: economic, operational, technical, social and legal. This presentation of the problem allows for an in-depth recognition of the issue and realizing that in order to achieve the goals set by the Legislator, close cooperation of all stakeholders is necessary both at the national and local level, while engaging energy groups, financial companies, electric vehicle manufacturers, and above all local government units in these activities.
Samples of steam coal used in heat and power plants as well as densimetric fractions obtained on a laboratory scale by dense organic liquid separation have been examined. The contents of ash, mercury, chromium, cadmium, copper, nickel and lead have been determined in coal, in the light and medium fraction as well as in the refuse. The degree of removal of mineral matter and the examined heavy metals as well as the coal combustible parts yield have been determined. Examination of 5 coals revealed that it is possible to remove 41% of mercury and more than 35% of other heavy metals bound to mineral matter in coal.
The objective of this study was to determine the suitability of the nanofi ltration (NF) process to recover the regenerating agent (NaOH) from spent solutions contaminated with organic compounds. NaOH recovery from 2 spent regenerant solutions after cleaning ultrafiltration (UF) membranes (polymeric 30 kDa, ceramic 300 kDa) fouled with natural humic water was carried out using 2 types of NF membranes: NP010P (Na2SO4 rejection: 35–75%) and NP030P (Na2SO4 rejection: 80–95%). It has been shown that the use of the NP030P membrane allows for very high separation effi ciency of organic compounds (up to 97% of color intensity reduction) from the tested solutions. It was also observed that the effectiveness of the process, in addition to the type of membrane used, also depends on the time of NF process – along with the elapsed time of the process, the hydraulic and separation properties of the tested membranes deteriorated. The obtained results showed that the use of both tested NF membranes allows for the recovery of NaOH to a degree that allows its re-use.
In the processes of coal mining, preparation and combustion, the rejects and by-products are generated. These are, among others, the rejects from the coal washing and dry deshaling processes as well as the coal combustion by-products (fly ash and slag). Current legal and industry regulations recommend determining the content of mercury in them. The regulations also define the acceptable content of mercury. The aim of the paper was to determine the mercury content in the rejects derived from the coal cleaning processes as well as in the combustion by-products in respect of their utilization. The mercury content in the representative samples of the rejects derived from the coal washing and dry deshaling processes as well as in the coal combustion by products derived from 8 coal-fired boilers was determined. The mercury content in the rejects from the coal washing process varied from 54 to 245 μg/kg, (the average of 98 μg/kg) and in the rejects from the dry deshaling process it varied from 76 to 310 μg/kg (the average of 148 μg/kg). The mercury content in the fly ash varied from 70 to 1420 μg/kg, (the average of 567 μg/kg) and in the slag it varied from 8 to 58 μg/kg (the average of 21 μg/kg). At the moment, in light of the regulations from the point of view of mercury content in the rejects from the coal preparation processes and in the coal combustion by-products, there are no significant barriers determining the way of their utilization. Nevertheless, in the future, regulations limiting the maximum content of mercury as well as the acceptable amount of leachable mercury may be introduced. Therefore, preparing for this situation by developing other alternative methods of using the rejects and by-products is recommended.
The removal of inclusions is a major challenge prior to the casting process, as they cause a discontinuity in the cast material, thereby lowering its mechanical properties and have a negative impact on the feeding capability and fluidity of the liquid alloys. In order to achieve adequate melt quality for casting, it is important to clean the melts from inclusions, for which there are numerous methods that can be used. In the course of the presented research, the inclusion removal efficiency of rotary degassing coupled with the addition of different fluxes was investigated. The effects of various cleaning fluxes on the inclusion content and the susceptibility to pore formation were compared by the investigation of K-mold samples and the evaluation of Density Index values at different stages of melt preparation. The chemical composition of the applied fluxes was characterized by X-ray powder diffraction, while the melting temperature of the fluxes was evaluated by derivatographic measurements. It was found that only the solute hydrogen content of the liquid metal could be significantly reduced during the melt treatments, however, better inclusion removal efficiency could be achieved with fluxes that have a low melting temperature.
A number of technologies is developed that substitute simple metal cores in the high-pressure casting technology. Soluble cores, namely
on the salt basis, represent the highest prospect. The contribution gives the results of the production of salt cores by high-pressure
squeezing and shooting with using a binder. Special attention is paid to the shape of NaCl salt crystals with additives and the influence on
strength properties of cores. A technology of bonding the salt cores is developing. Salinity of circulating water is studied and it is checked
with the aid of electrical conductance.
Nowadays, actions allowing for a reduction of anthropogenic mercury emission are taken worldwide. Great emphasis is placed on reducing mercury emission from the processes of energochemical coal conversion, mainly from the coal combustion processes. One of the methods which enable a reduction of anthropogenic mercury emission is the removal of mercury from coal before its conversion. It should be pointed out that mercury in hard coal may occur both in the organic and mineral matter. Therefore, a universal method should allow for the removal of mercury, combined in both ways, from coal. In the paper, a concept of the hybrid mercury removal process from hard coal was presented. The idea of the process is based on the combination of the coal cleaning process using wet or dry methods (first stage) and the thermal pretreatment process at a temperature in the range from 200 to 400 °C (second stage). In the first stage, a part of mercury occurring in the mineral matter is removed. In the second stage, a part of mercury occurring in the organic matter as well as in some inorganic constituents characterized by a relatively low temperature of mercury release is removed. Based on the results of the preliminary research, the effectiveness of the decrease in mercury content in coal in the hybrid process was estimated in the range from 36 to 75% with the average at the level of 58%. The effect of the decrease in mercury content in coal is much more significant when mercury content is referred to a low heating value of coal. So determined, the effectiveness was estimated in the range from 36 to 75% with the average at the level of 58%.
U-10wt.%Zr-5wt.%RE fuel slugs for a sodium-cooled fast reactor (SFR) were conventionally prepared by a modified injection casting method, which had the drawback of a low fabrication yield rate of approximately 60% because of the formation of many metallic fuel scraps, such as melt residue and unsuitable fuel slug butts. Moreover, the metallic fuel scraps were classified as a radioactive waste and stored in temporary storage without recycling. It is necessary to develop a recycling process technology for scrap wastes in order to reduce the radioactive wastes of the fuel scraps and improve the fabrication yield of the fuel slugs. In this study, the additive recycling process of the metallic fuel scraps was introduced to re-fabricate the U-10wt.%Zr-5wt.%RE fuel slugs. The U-10wt.%Zr-5wt.%RE fuel scraps were cleaned on the surface impurity layers with a mechanical treatment that used an electric brush under an Ar atmosphere. The U-10wt.%Zr-5wt.%RE fuel slugs were soundly re-fabricated and examined to evaluate the feasibility of the additive process compared with the metallic fuel slugs that used pure metals.