Distributed estimation and control of a four-tank process

A multivariable process of four interconnected water tanks is considered for modeling and control. The objective of the current study is to design and implement a distributed control and estimation (DEC) for a multivariable four-tank process. Distributed model and inter-nodal communication structure are derived from global state–space matrices, thus combining the topology of plant flow sheet and the interaction dynamics across the plant subunits. Using experimental data, the process dynamics and disturbance effects are modeled. A typical lab-scale system was simulated and the obtained results demonstrated the potential of the DEC algorithm.

Synthesis and characterization of fat-liquor from waste tallow

The fat-liquoring is an important step in leather making before dying to improve the glossiness, appearance, physical and chemical qualities of the leather. Synthetic sulphonated or sulphited oils are generally used to fill fibrous leather & to give it soft, elastic and loose characteristics. Natural fat-liquors (vegetable and animal-based) and synthetic fat-liquors are the two types of emulsions. The emulsion’s charge can be anionic, cationic, or nonionic. In this study, fat-liquor has been made from a bio-waste, namely tallow, which is obtained from a slaughterhouse as a byproduct of the animal hides and skin processing for leather. Triglycerides, a combination of oleic, stearic, and palmitic fatty acids, and glycerol make up the majority of this animal fat. Fat-liquor is made through a series of three reactions, namely, amidation, esterification, and sulphitation. Amidation helps to increase the hydroxyl groups. To react with fat, alkanol amine with a wide emulsifying characteristic isutilised. Anhydrides derived from di-carboxylic acids were then esterified with amidated fat in the next phase. By altering the process recipe, the stability of the emulsion product has been examined, and required raw materials are optimized. Finally, aqueous hydrolyzed sodium metabisulphite is used to sulphite the product, yielding bisulphite and hydroxide ions. The saponification and acid values are computed. The end product has a distinct advantage (anti-foaming & fire-retardant) over traditional fat-liquoring techniques. Material balance is performed once the process flow sheet was created. The process has been scaled up with the help of a preliminary reactor design. The degree of fat-liquoring and the process’ performance are revealed by FTIR spectrum. NMR was used to determine the final product’s structure.

Recovery of Rare Earth Metals (REMs) from Nickel Metal Hydride Batteries of Electric Vehicles

Nickel metal hydride (NiMH) batteries are extensively used in the manufacturing of portable electronic devices as well as electric vehicles due to their specific properties including high energy density, precise volume, resistance to overcharge, etc. These NiMH batteries contain significant amounts of rare earth metals (REMs) along with Co and Ni which are discarded due to illegal dumping and improper recycling practices. In view of their strategic, economic, and industrial importance, and to mitigate the demand and supply gap of REMs and the limited availability of natural resources, it is necessary to explore secondary resources of REMs. Therefore, the present paper reports a feasible hydrometallurgical process flowsheet for the recovery of REMs and valuable metals from spent NiMH batteries. More than 90% dissolution of REMs (Nd, Ce and La) was achieved using 2 M H2SO4 at 75 °C in 60 min in the presence of 10% H2O2 (v/v). From the obtained leach liquor, the REMs, such as Nd and Ce, were recovered using 10% PC88A diluted in kerosene at eq. pH 1.5 and O/A ratio 1/1 in two stages of counter current extraction. La of 99% purity was selectively precipitated from the leach liquor in the pH range of 1.5 to 2.0, leaving Cu, Ni and Co in the filtrate. Further, Cu and Ni were extracted with LIX 84 at equilibrium pH 2.5 and 5, leaving Co in the raffinate. The developed process flow sheet is feasible and has potential for industrial exploitation after scale-up/pilot trails.

Thermal Performance of Integrated Direct Contact and Vacuum Membrane Distillation Units

An integrated membrane distillation (MD) flowsheet, consisting of direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) units, was proposed and analysed in terms of thermal performance and water recovery factor, for the first time. The same lab-scale membrane module (40 cm2) was used for carrying out experiments of DCMD and VMD at fixed feed operating conditions (deionised water at 230 L/h and ~40 °C) while working at the permeate side with deionised water at 18 °C and with a vacuum of 20 mbar for the DCMD and the VMD configuration, respectively. Based on experimental data obtained on the single modules, calculations of the permeate production, the specific thermal energy consumption (STEC) and the gained output ratio (GOR) were carried out for both single and integrated units. Moreover, the calculations were also made for a flow sheet consisting of two DCMD units in series, representing the “traditional” way in which more units of the same MD configuration are combined to enhance the water recovery factor. A significant improvement of the thermal performance (lower STEC and higher GOR) was obtained with the integrated DCMD–VMD flowsheet with respect to the DCMD units operating in series. The integration of DCMD with VMD also led to a higher permeate production and productivity/size (PS) ratio, a metric defined to compare plants in terms of the process intensification strategy.

Recovery of Cassiterite and Topaz Minerals from an Old Metallurgical Dump, Eastern Desert of Egypt

Huge amounts of tailing dumps as a result of mines’ blasting operations were impacting both economical and environmental problems. This issue was in serious need to be treated with suitable solutions. Evaluation of one of these tailing dumps in the Eastern Desert of Egypt showed the presence of reasonable amount of cassiterite mineral reaching 0.199%. The mineral was found as finely disseminated particulates within varieties of quartz-feldspar-hornblende-biotite granitic formations. In the present study, the processing regime relied upon the synergy between reaching liberation size, and mineral over grinding due to its extreme brittleness. However, delicate grinding via attrition scrubbing was adopted to produce − 0.51 + 0.074 mm attrition product with fine fractions, reaching 62.31% and 37.59%, respectively. The recovery of cassiterite from the − 0.50 + 0.074 mm size fraction was accomplished by the physical difference between mother granitic formations that shielded the mineral grains. Under these conditions, joint shaking table/dry high intensity magnetic separation techniques were conducted to recover cassiterite mineral. The CCD statistical system was used as a mathematical approach to optimize the effect of the main working parameters of the magnetic separator, i.e., splitter inclination angle, and belt speed, and their interactions on the cassiterite recovery of the final concentrate. The suggested flow sheet succeeded to recover cassiterite mineral with a grade reaching 11.25% SnO2 with 94.08% operational recovery from a feed contained 0.19% SnO2. These results are highly imperative to achieve applicable processing flow-sheet of such kind of minerals’ secondary resources.

Reaction Sequences in Flash Smelting and Converting Furnaces: An In-depth View

Flash smelting and flash converting are mature technologies in copper and nickel sulfide smelting. The sensitivity of operation concerning the furnace design is evident. It is obvious that when two unit operations are carried out in separate spaces in the same furnace, skills related to maintenance of suspension oxidation of fine minerals, fluxing, fluid as well as heat flows and the overall energy balance are required. Despite these fundamental features, the flow-sheet wide understanding of linking the suspension oxidation of sulfides with the subsequent smelting processes in the furnace as well as the chemistry of its off-gas train is largely absent in the scientific literature. This review gives a detailed outlook on the microscale phenomena in flash smelting and flash converting furnaces accumulated during the last decades. It connects their vital features and chemistries with the reaction tendencies and heat fluxes in the different parts and reaction zones of the furnace as well as in the off-gas train from the smelter to the acid plant. Graphic Abstract

Preparation of collective lead-zinc concentrates for selection cycle

The object of the study is a collective concentrate, which was obtained by flotation of sulfide lead-zinc ore from an East Siberian deposit using a combination of diesel fuel and butyl xanthate. In the collective concentrate the main ore minerals are galena and sphalerite. Non-metallic minerals are quartz, dolomite, calcite and chlorite. In the work were studied various methods of preparing a collective concentrate for a flotation selective cycle: without pulp preparation, washing with sodium sulfide, temperature, ultrasound, and bacterial treatment of a collective concentrate. The results of studies of the flotation selective cycle showed that it is impossible without preparation. Satisfactory technological indicators were not obtained when applying twice washing with sodium sulfide and using ultrasound. Introduction to the flow sheet of the operation of steaming in a medium of sodium sulfide and dosing of activated carbon into the process made it possible to obtain a foam product (lead concentrate) with a lead content of 45%, but the recovery was ~ 43%. In addition, the process is environmentally unfavorable, characterized by high material and energy costs. The prospects of using the bacterial method for preparing collective concentrates using diesel fuel for the flotation selective cycle are shown. The bacterial method consists in treating the collective concentrate with the bacteria Ochrobactrum anthropi and Pseudomonas aeruginosa JCM 5962.

DIELECTRIC OIL`S TEST MACHINE WISH VOLTAGE RISE ELECTRONIC MODULE

For test operations according to the liquid dielectric breakdown voltage measurement method we use high voltage machines that consist of high-voltage step-up transformer, voltage rise block, test cell with electrodes and so on. Described dielectric oil's test machine UIM – 90 with electromechanical voltage rise block. Cause of hard requirements in specification documents about voltage sine wave form on cell's electrodes, we performed field tests for UIM – 90 that help to evaluate the mains voltage impact on the test voltage distortion and measurement accuracy. Was discovered that during usage of electromechanical voltage rise block voltage steps disrupt sine wave’s form proportionally to step-up transformer’s transformation coefficient. Performed analysis of this block’s construction and established that usage of ЛАТР and mechanical voltage controller could lead to additional sine’s wave disruption. Decided to develop electronic voltage rise block which will allow to get rid of mains influence on test data. Created the algorithm of wave shaping from microcontroller, which generates voltage ramp to the amplifier representing pulse width modulator, then to the step-up transformers cascade. Proposed to use additional transformer for level matching of amplifier’s output voltage and main high voltage transformer’s input voltage. Presented flow sheet for UIM – 90 with electronic voltage step-up block and cascading start ofstep-up transformers. Provided voltage oscillograph trace and it spectrograph on the main transformer’s primary side, received due to the implementation of developed electronic voltage step-up block, prove that voltage sine wave form doesn’t rely on mains quality. After upgraded UIM – 90 and it world analogues technical parameters analysis we could make a conclusion about it competitive capability on global level.

Combined Vapor Permeation and Continuous Solid-State Distillation for Energy-Efficient Bioethanol Production

Extracting ethanol by steam directly from fermented solid-state bagasse is an emerging technology of energy-efficient bioethanol production. With continuous solid-state distillation (CSSD) approach, the vapor with more than 25 wt% ethanol flows out of the column. Conventionally, the vapor was concentrated to azeotrope by rectification column, which contributes most of the energy consumption in ethanol production. As an alternative, a process integrating CSSD and vapor permeation (VP) membrane separation was tested. In light of existing industrial application of NaA zeolite hydrophilic membrane for dehydration, the prospect of replacing rectification operation with hydrophobic membrane for ethanol enriching was mainly analyzed in this paper. The separation performance of a commercial PDMS/PVDF membrane in a wide range of ethanol–water-vapor binary mixture was evaluated in the experiment. The correlation of the separation factor and permeate flux at different transmembrane driving force was measured. The mass and energy flow sheet of proposed VP case and rectification case were estimated respectively with process simulation software based on experimental data. Techno-economic analysis on both cases was performed. The results demonstrated that the additional VP membrane cost was higher than the rectification column, but a lower utilities cost was required for VP. The discount payback period of supplementary cost for VP case was determined as 1.81 years compared with the membrane service lifetime of 3 years, indicating that the hybrid CSSD-VP process was more cost effective and energy efficient.

Processing Technogenic Raw Materials-Phosphorus Slags with the Production of Precipitated Nanosilica and Simultaneous Recovery of Valuable Components

The paper provides a flow sheet of the phosphorus slag processing to produce precipitated silica (white soot). The process conditions for opening phosphorus slag at the I stage of leaching have been selected: the nitric acid concentration is 3.5 mol/dm3; the ratio S:L = 1:3.5; the temperature is 60 oС; and the process duration is 1 hour. The parameters of the white soot production II stage have been determined: the HNO3 concentration is 6.5 mol/dm3; the ratio S:L = 1:3.5; the temperature is 50 oС; and the process duration is 1 hour. The temperature effect on the white soot structure and the specific surface have been established. At optimal process parameters, the white soot batches have been obtained with the main SiO2 component content of 88.2 and 90.5 %, and a specific surface of 170 and 182 m2/g, respectively. The through recovery of silicon into a commercial product is 98.0 % of its initial content in slag.