Coal Mining Energy Utilization and Environmental Impact Management Strategy Using the LCA Method

Coal mining processing and the clearing of land require that materials which have been removed be carefully inspected before it is reused. In this study, the boundary of our model starts with excavation and ends with material recovery. Therefore, further processing of the material to be recovered (recycling, reprocessing) is excluded from the model. In this study, the topsoil layer was collected in three pits numbered one, two, and three, from January to December 2020. The use of the LCA method gives results after the inventory data is carried out, which results in global warming. The results showed material removal unit process generated a total CO2 value of 32.44 kg CO2- eq.tonne-1 of coal, and the coal mining unit process generated a total CO2 value of 255.99 kg CO2- eq.tonne-1 of coal, for the impact of global warming. When compared to the material removal process, the results of the coal mining unit process show the highest global warming impact. Coal processing gives a yield of 25.61 kg CO2- eq.tonne-1 of coal. So that the resulting impact as a whole is 314 kg CO2- eq.tonne-1 of coal. The total emissions resulting from B30 fuel (314 kg CO2- eq.tonne-1 of coal) are smaller than B20 fuel (320 kg CO2- eq.tonne-1 of coal), 6 kg CO2-eq.tonne-1 of coal. The coal mining process includes fuel used in coal extraction, coal hauling, coal stockpiling, blasting, water pumps, and water tracks.

Methodology for criteria-based assessment of energy efficiency of main pipeline pumps

В настоящее время об энергоэффективности насосного агрегата судят на основании результатов приемо-сдаточных испытаний - по значению КПД в номинальной рабочей точке. Опыт эксплуатации насосов на объектах нефтепроводного транспорта показывает, что реальная рабочая точка насоса отличается от номинальной. Данное расхождение объясняется вариативностью режимов работы насосных установок. В этой связи предлагается оценивать энергоэффективность насоса по результатам испытаний исходя из реальных условий функционирования насосного оборудования - в рабочем диапазоне, необходимом для перекачки нефти (нефтепродуктов) с учетом изменения потребной подачи и напора гидросистемы. Существующие методики оценки энергоэффективности насосов в рабочем диапазоне имеют ограничения для применения на объектах магистральных нефтепроводов. В настоящей работе предлагается использовать с этой целью критериальную оценку по характерным точкам в диапазоне подач. Сформулированы основные положения разработанной методики. Сделан вывод о том, что ее применение при приемо-сдаточных испытаниях позволит улучшить качество оборудования, поставляемого на производственные объекты, а следовательно, энергоэффективность НПС. Currently, energy efficiency of a pumping unit is assessed based on the acceptance test results according to the efficiency value at the nominal working point. The experience of operating pumps at oil pipeline transportation facilities shows that the actual working point of the pump differs from the nominal one. This discrepancy is explained by the variability of the pumping unit process modes. In this connection, it is proposed to evaluate pump’s energy efficiency based on the test results under the actual operating conditions of the pumping equipment, in the operating range required for pumping oil (petroleum products), taking into account the change in the required supply and hydraulic system pressure. The existing methods for assessing energy efficiency of pumps in the operating range have limitations for use at main oil pipeline facilities. This study proposes to use a criteria-based assessment using characteristic points in the supply range for this purpose. The basic principles of the developed method are formulated. It is concluded that its application during the acceptance tests will improve the quality of equipment supplied to production facilities, and hence the PS energy efficiency.

A Reusable Unit Process Life Cycle Inventory Model for Infeed Centerless Grinding

Environmental impact minimization is an important aspect for improving the sustainability performance of manufacturing processes. Quantifying the environmental impacts of unit manufacturing processes requires systematic modeling of process life cycle inventories. This paper develops an inventory model for infeed centerless grinding based on the unit process life cycle inventory methodology. The developed model estimates the energy consumption, material losses, and consumable fluids, for a typical high-volume production setup. Process consumption data is estimated from parameters directly used for process setup as well as machine and tool specifications that can be easily obtained from technical documentation and product geometrical specification. The developed model is demonstrated using a case study involving the infeed centerless grinding of an Inconel 718 shaft on a Cincinnati Twin-Grip Centerless Grinding Machine.

Method of combined treatment of air terminal wastewater and liquid wastes from dry closets of aircrafts

В состав сточных вод аэровокзалов входят хозяйственно-бытовые и производственные стоки от технологического оборудования пищеблока. Технологические схемы очистки сточных вод аэровокзалов не предусматривают прием и очистку жидких отбросов от биотуалетов самолетов, которые являются высококонцентрированными по показателям ХПК, азот аммонийный, фосфор. Кроме того, они содержат высокие концентрации дезинфицирующих средств, действующим веществом которых являются четвертичные аммониевые соли (ЧАС), токсичные для микроорганизмов. В результате поступления жидких отбросов на действующие очистные сооружения аэровокзала качественные показатели биологической очистки сточных вод значительно ухудшились, также изменились свойства биоценоза биопленки. Целью исследований являлось определение способа снижения концентрации ЧАС до значений, при которых прекращается токсичное воздействие на биоценоз биопленки, и определение соответствующей технологической схемы. Представлен анализ литературных данных по воздействию ЧАС на микроорганизмы активного ила, на основании которого выполнены лабораторные исследования и разработан способ подготовки жидких отбросов из биотуалетов самолетов для последующей их совместной очистки с хозяйственно-бытовыми сточными водами аэропорта. В ходе испытаний определена эффективность сорбции предварительно регенерированным избыточным активным илом загрязняющих веществ, в том числе и ЧАС. Определены технологические параметры процессов, разработана и внедрена эффективная, надежная, простая в эксплуатации технологическая схема совместной очистки хозяйственно-бытовых сточных вод аэровокзала и жидких отбросов биотуалетов самолетов. The composition of the wastewater of air terminals includes sewage and industrial wastewater from the technological equipment of the food unit. Process flow schemes for wastewater treatment of air terminals do not provide for the reception and treatment of liquid wastes from water closets of aircrafts, that are highly concentrated in terms of COD, ammonium nitrogen, phosphorus. In addition, they contain high concentrations of disinfectants with quaternary ammonium salts (QAS) as an active ingredient toxic to microorganisms. As a result of liquid waste discharge to the operating treatment facilities of the air terminal, the quality indicators of biological wastewater treatment have significantly deteriorated, and the properties of the biocenosis of the biofilm have also changed. The aim of the research was to determine a method for reducing the concentration of QAS to the level where the toxic effect on the biofilm biocenosis ceased, and to develop an appropriate process flow scheme. An analysis of the literature data on the impact of QAS on activated sludge microorganisms is presented; on this basis laboratory studies were carried out and a method was developed for the pre-treatment of liquid waste from aircraft water closets for the subsequent combined treatment with the air terminal sewage. In the course of the tests, the efficiency of pollution sorption, including QAS, by the preliminary regenerated excess activated sludge was determined. The technological parameters of the processes were determined; an efficient, reliable, easy-to-use process flow scheme for the combined treatment of sewage of the air terminal and liquid waste of water closets of aircrafts was developed and implemented.

Economic realities and management systems in aquaculture production

This study reviewed and unveiled the economic sizes and managing systems in aquaculture production. The focus had been on developing new technologies and management systems in aquaculture production that can produce fish food on an economically competitive basis while still maintaining environmental health. The technique of recirculating aquaculture system (RAS) had been discussed. Economic issues such as: adequately available quality water, economic sizes, management issues, financial capabilities, various investment options, species selection, cost of production, capitalization cost of unit process, cost of pumping and bio-filtration, gas stripping and pH control, solid wastes removal, economically competitive scale, labor requirements as wellas predicted cost of production. The economic comparison of broilers and catfish production were evaluated. Also, challenges against the effective aquaculture technological application and the prospects to economic realities and management systems in aquaculture production were also highlighted. It could be concluded that economic realities and management of RAS is the soft and live wire in aquacultural development especially in developing countries like Nigeria. It is therefore, recommended that fish farmers need to engage and be trained on the use of this new fish production technology for increase production and economy benefits.

Dirt Loss Estimator for Photovoltaic Modules Using Model Predictive Control

The central problem tackled in this article is the susceptibility of the solar modules to dirt that culminates in losses in energy generation or even physical damage. In this context, a solution is presented to enable the estimates of dirt losses in photovoltaic generation units. The proposed solution is based on the mathematical modeling of the solar cells and predictive modeling concepts. A device was designed and developed to acquire data from the photovoltaic unit; process them based on a predictive model, and send loss estimates in the generation unit to a web server to help in decision-making support. The results demonstrated the real applicability of the system to estimate losses due to dirt or electrical mismatches in photovoltaic plants.

Comparative LCA of Automotive Gear Hobbing Processes with Flood Lubrication and MQL

The Life Cycle Inventory (LCI) data of a gear hobbing was obtained by means of the methodology Unit Process Life Cycle Inventory (UPLCI), in order to conduct a comparative Life Cycle Assessment (LCA) between hobbing assisted by Flood Lubrication (FL) and Minimum Quantity Lubrication (MQL). The results of the LCIA pointed out 4 among 11 normalized environmental impact categories totalized more than 80% of the accumulated impacts: fossil depletion (43%), climate changes (19%), terrestrial acidification (11%) and freshwater consumption (8%). The identified hotspot in the case study was the input flow of raw material for the system “Hobbing Machine”, which was linked to more than 75% of the total amount of normalized potential environmental impacts. Once, changes on raw material depends on the gear design, the research focused on the environmental aspects of energy and cutting fluid consumption, which depends directly on the hobbing process parameters. The introduction of MQL provided reduction of 70.77% on the total amount of normalized potential environmental impacts, while the strategies to reduce electric energy consumption by the machine tool accounted only for 3.74%. The consumption of energy and cutting fluids are the main environmental aspects of the gear hobbing process itself, since they are directly associated to the majority of potential environmental impacts derived from that machining operation. Nevertheless, when raw material flow is taken into account in the LCA, it turns into the process hotspot, due to high energy demanded in the steel-making process, forging and turning operations to shape the semi-finished gear.

The Evolution of Manufacturing Technology for GaN Electronic Devices

GaN has been widely used to develop devices for high-power and high-frequency applications owing to its higher breakdown voltage and high electron saturation velocity. The GaN HEMT radio frequency (RF) power amplifier is the first commercialized product which is fabricated using the conventional Au-based III–V device manufacturing process. In recent years, owing to the increased applications in power electronics, and expanded applications in RF and millimeter-wave (mmW) power amplifiers for 5G mobile communications, the development of high-volume production techniques derived from CMOS technology for GaN electronic devices has become highly demanded. In this article, we will review the history and principles of each unit process for conventional HEMT technology with Au-based metallization schemes, including epitaxy, ohmic contact, and Schottky metal gate technology. The evolution and status of CMOS-compatible Au-less process technology will then be described and discussed. In particular, novel process techniques such as regrown ohmic layers and metal–insulator–semiconductor (MIS) gates are illustrated. New enhancement-mode device technology based on the p-GaN gate is also reviewed. The vertical GaN device is a new direction of development for devices used in high-power applications, and we will also highlight the key features of such kind of device technology.

Life Cycle Assessment of the NdFeB Recycling Process Route for Oil Sludge Waste Treatment

In this paper, based on the life cycle concept of oil sludge waste from the NdFeB manufacturing process, we investigate the process technology route to recover valuable elements from the oil sludge waste by hydro-metallurgical refining and calcium reduction to fabricate a sintered NdFeB magnet. The life cycle list was calculated and the environmental impact of the main processes was examined using the ReCiPe method, and the main factors of environmental impact were identified. The results showed that the hydrometallurgical technology route, compared with the calcium reduction technology route, resulted in 119.84% of human health hazards, 119.84% of ecological damage and 119.84% of resource. The consumption was found to be 13.08% higher than that of FDP. The sensitivity analysis revealed that the production of hydrochloric acid is highly sensitive to FDP, and power consumption is high to WTP in the hydrometallurgical technology route, and WTP in the calcium reduction unit process, and HTP in all processes in the calcium reduction technology route. The overall results show that reducing the environmental impact in the calcium reduction recovery process and accelerating the clean production of China's power resources are of great significance for the recovery of oil sludge waste for the preparation of recycled sintered NdFeB.