Calcium Carbide Method Research Articles

Research the Instrument of Karl Fischer Titration How to Detect the Moisture Content from Transformer Insulating Oil

This article focuses on the monitoring and control of the moisture content from the transformer insulating oil. When its moisture content exceeds the standard value, it will endanger the normal operation of the equipment and cause accidents. Research on how the moisture content penetrates into the insulating oil of the transformer. How to diagnose the moisture content is an important issue under the premise of affecting hidden worries about the quality of power supply？ Currently, there are three types of moisture content detecting: "visual", "calcium carbide method" and "liquid chromatography." This article will use the most accurate and effective "liquid chromatography", also referred to as "Karl Fischer coulometric titration" or "ASTM D6304-20", as the vertical axis and "monitoring and control" as the horizontal axis to analyze and discuss the moisture of generation in transformer insulating oil and detection methods to compose throughout them for an article. When the detecting oil sample has measured without contamination under normal procedures which has 30 to 35 ppm of moisture content, it is judged as a passing standard by ASTM D6304-20. If it exceeds standard level, the transformer equipment must be shut down for being deal with. To pay more attention on the item for detection of moisture content in insulating oil, so be doing that the transformer - related electrical accident failure which will be what It will not happen again similar accidents caused by moisture content. In addition to being a reference for maintenance technicians of substation equipment, this article can effectively monitor the moisture content inside the transformer to ensure the safe operation of the equipment.
 Detection Methods: the principle of the Karl Fisher Titration detection method is to employ the reaction of chemical between iodine (I2) and sulfur dioxide (SO2), and then absorb all the water (2H2O) from the insulating oil, while the chemical reaction produces sulfuric acid (H2SO4) and hydrogen iodide (2HI), so by doing to diagnose the moisture content in parts per million (ppm) of the oil sample.
 Detection Purpose: To explain "the Instrument of Karl Fischer Titration How to Detect the Moisture Content from Transformer Insulating Oil.”
 Detection Effectiveness: The most accurate and effective method of liquid chromatography, also known as Karl Fisher Titration which is employed for power companies.

Comparison of the Calcium Carbide Method and Darr Drying to Quantify the Amount of Chemically Bound Water in Early Age Concrete

Hydration is the exothermic reaction between anhydrous cement and water, which forms the solid cement matrix of concrete. Being able to evaluate the hydration is of high interest for the use of both conventional and more climate-friendly building materials. The experimental monitoring is based on temperature or moisture measurements. The first needs adiabatic conditions, which can only be achieved in laboratory. The latter is often measured comparing the weight of the material sample before and after oven drying, which is time-consuming. This study investigates the moisture content of two cement-based and two calcium sulphate based mixtures for the first 90 days by using the calcium carbide method and oven drying at 40 °C and 105 °C (Darr method). Thereby, the amount of chemically bound water is determined to derive the degree of hydration. The calcium carbide measurements highly coincide with oven drying at 40 °C. The calcium carbide method is therefore evaluated as a suitable alternative to the time-consuming Darr drying. The prompt results are seen as a remarkable advantage and can be obtained easily in laboratory as well as in the field.

A bi-level model integrating planning and scheduling for the optimization of process operation and energy consumption of a PVC plant under uncertainty

PVC production by the calcium carbide method is a typical hybrid system consisting of continuous and intermittent processing, and the optimization of the whole process scheduling is of practical significance. Still, the existence of uncertain factors in the external environment and production process makes it challenging to continue to implement deterministic scheduling. This paper, therefore, proposes an integration model, the discrete-time method applied in the planning layer, and the chance-constrained programming used to deal with external uncertainties. The continuous-time modeling method based on event points is adopted in the scheduling layer, and the optimization of equipment-level operations with variable production rates is performed. Then, the data-driven robust optimization method is applied to deal with endogenous uncertainty based on the data-driven flexible uncertainty set. Finally, the results provide valuable guidance to improve the robustness and stability of the production system under uncertainty. The comparative results verify the effectiveness and superiority of the proposed model in total cost and energy consumption.

A Combined Algorithm Using Both the MINLP Model and Approximated MILP Model for PVC Production Scheduling.

In this paper, a scheduling model of PVC production by a calcium carbide method is designed based on a continuous-time modeling method, and an improved mixed-integer nonlinear programming (MINLP) model for scheduling of PVC production is proposed. The optimization goal is to minimize the total cost. Considering the practical requirements of both the solution rapidity and quality, a combined algorithm is further established using both the MINLP model and approximated mixed-integer linear program (MILP) model for PVC production scheduling. The optimization result of the linear model is substituted into the original MINLP model as the initial value of variables to accelerate the solution process. Then, the optimal solution of the improved model is executed. Afterward, the effectiveness of the proposed method is verified with two actual cases. The comparative results demonstrate that the proposed algorithm can significantly accelerate the computation and obtain more accurate optimal solution.

CO2 mineralization of carbide slag for the production of light calcium carbonates

The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption, leading to massive flue gas and carbide slag emissions. Currently, the carbide slag with high CaO content is usually stacked in residue field, easily draining away with the rain and corroding the soil. In this work, we coupled the treatment of flue gas and carbide slag to propose a facile CO2 mineralization route to prepare light calcium carbonate. And the route feasibility was comprehensively evaluated via experiments and simulation. Through experimental investigation, the Ca2+ leaching and mineralization reaction parameters were determined. Based on the experiment, a process was built and optimized through Aspen Plus, and the energy was integrated to obtain the overall process energy and material consumption. Finally, the net CO2 emission reduction rate of the entire process through the life-cycle assessment method was analyzed. Moreover, the relationship between the parameters and the CO2 emission life-cycle assessment was established. The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO2)−1 of energy (including heat energy of 979.32 kW·h·(t CO2)−1 and electrical energy of 175.37 kW·h·(t CO2)−1), and the net CO2 emission reduction rate was 35.8%. The light CaCO3 product can be sold as a high value-added product. According to preliminary economic analysis, the profit of mineralizing can reach more than 2,100 CNY·(t CO2)−1.

Life cycle assessment of acetylene production from calcium carbide and methane in China

Currently, resource and environmental issues are becoming increasingly prominent, and human populations are facing many challenges from this perspective. Acetylene is an important raw material in China's national economy, but previous studies on the environmental performance of its production process were not sufficiently comprehensive. In this study, a life cycle assessment was conducted, using the CML 2001 method, to evaluate the environmental impact of acetylene production using the calcium carbide, methane partial oxidation, and methane plasma methods. At the same time, the impacts of technology improvements, energy substitution, and policy planning on the environmental performance of the three acetylene production methods were studied. The results showed that under the current electric power generation structure, the partial oxidation method exhibited the best environmental performance, followed by the plasma method. With increasing use of renewable energy in China, the plasma method will eventually have more advantages than the partial oxidation method, in terms of its environmental credentials; the environmental performance gap between the calcium carbide method and the other two methods will gradually narrow. The purposes of this study were to compare the environmental performance of these three acetylene production methods, to find ways to reduce the environmental burdens of acetylene production, and to provide a reference for the sustainable development of the acetylene industry in China.

Neutron Radiography and Tomography of the Drying Process of Screed Samples.

The moisture content of screed samples is an essential parameter in the construction industry, since the screed must dry to a certain level of moisture content to be ready for covering. This paper introduces neutron radiography (NR) and neutron tomography (NT) as new, non-destructive techniques for analysing the drying characteristics of screed. Our NR analyses evaluate the results of the established methods while offering much higher spatial resolution of 200 m, thereby facilitating a two- and three-dimensional understanding of screed’s drying behaviour. Because of NR’s exceptionally high sensitivity regarding the total cross section of hydrogen the precise moisture content of screed samples is obtainable, resulting in new observations. The current methods to measure moisture content comprise the ‘calcium carbide method’, the ‘Darr method’, and electrical sensor systems.

Critical analysis of residual water in self-leveling underlayment – Part I: Study on model materials

A self-leveling underlayment is a thin layer used to smooth floors and has to contain a very low level of residual water prior to covering with the final coating. Therefore, the evaluation of residual water is a key point. The aim of this study is to compare two residual water evaluation techniques: the calcium carbide method (CCM) and oven drying at 40 °C. The following model materials are investigated: silica, gypsum, plaster, and ettringite. The CCM measurements provide an effective indicator of free water for silica and gypsum. Although not a field measurement, oven drying offers a reliable and truly representative measure of the residual water, regardless of the material used.

Analiza porównawcza badań wilgotnościowych metodą chemiczną w stosunku do badań grawimetrycznych wybranych materiałów budowlanych

Metoda grawimetryczna, metoda bezpośrednia, uznawana jest za jedyny miarodajny sposób badania wilgotności. Funkcjonuje jednocześnie wiele metod pośrednich gdzie wynik pomiaru obarczony jest mniejszym lub większym błędem. Głównym celem artykułu jest określenie dokładności otrzymywanych wyników metodą chemiczną w stosunku do metody grawimetrycznej oraz wyznaczenie wzorów regresyjnych potrzebnych do skorygowania wyników.

Multiperiod Planning of a PVC Plant for the Optimization of Process Operation and Energy Consumption: An MINLP Approach

This work addresses the integrated optimization of both the plant-wide material processing system and the utility system for a polyvinyl chloride (PVC) plant. In the plant-wide material processing system, vinyl chloride monomer (VCM) production process and VCM polymerization process are optimized to determine production allocation and switching operation of parallel equipment as well as raw material supply arrangement. In the utility system, power generation/supply plan is determined by combined heat and power (CHP) units and the state grid. The nonlinear electricity consuming characteristics of calcium carbide production process, CHP process, and electrolysis process are modeled based on the industrial data. A multiperiod mixed-integer nonlinear programming (MINLP) model of a PVC plant by calcium carbide method is proposed with the intent to enhance the profit and reduce the energy consumption. The proposed MINLP model is successfully applied to two cases originated from a real-world industrial plant in ...

Decomposition Algorithm for the Scheduling of Typical Polyvinyl Chloride Production by Calcium Carbide Method

In our previous work (Tian et al. Ind. Eng. Chem. Res. 2016, 55(21), 6161–6174), a plantwide scheduling model was presented, which was difficult to solve for industrial scale instances in acceptable time. Because the vinyl chloride monomer (VCM) buffer links the continuous process with the batch process, the whole scheduling problem can be decomposed into the upstream VCM production processes and the downstream polymerization processes. Thus, a decomposition algorithm is presented in this paper to accelerate the computation progress. Using the decomposition algorithm, the polymerization scheduling optimization problem is first conducted and thus the detailed VCM demand schedule is obtained. Then, with an off-line model formulated in advance, the operating states (i.e., start/stop operations) of arc furnaces are optimized in the second step, which would be the hard-to-solve binary variables in the plantwide scheduling model. In the off-line work, the furnaces operating range (i.e., the production rate) is ...

Plantwide Scheduling Model for the Typical Polyvinyl chloride Production by Calcium Carbide Method

The polyvinyl chloride (PVC) production by calcium carbide method accounts for the majority of PVC in the market in China, the largest market share in the world. Due to high energy costs, increasingly stringent requirements on emission reduction, and intense global competition, the scheduling optimization of PVC production processes, as an effective way to improve profit, is drawing increasing attention. However, most research is only focused on the scheduling of vinyl chloride monomer (VCM) polymerization processes rather than plantwide scheduling optimization. Moreover, the majority of energy consumption lies in the upstream VCM preparation process, including calcium carbide and chlorine production processes. Therefore, plantwide scheduling optimization is of great importance for reducing the energy consumption and improving the overall profit. Hence, a discrete time representation based plantwide scheduling model is proposed in this paper. Since the operation characteristics in the time scales for VCM ...

Preparation of Fe3O4 magnetic porous microspheres (MPMs) and their application in treating mercury-containing wastewater from the polyvinyl chloride industry by calcium carbide method

Abstract Fe 3 O 4 magnetic porous microspheres (MPMs) were successfully synthesized by an easy one-step solvothermal method. The structure, specific surface area, and magnetic property of the MPMs were analyzed and confirmed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Brunauer–Emmett–Teller (BET) method, and vibrating sample magnetometry. The application of the MPMs in the treatment of Hg-containing wastewater released from a polyvinyl chloride plant by calcium carbide method was researched. Results indicated that the pore size of Fe 3 O 4 MPMs ranged from ∼31.0 to 56.0 nm, their BET surface area was 86.39 m 2 /g, and their pore volume was 0.3528 cm 3 /g. Their saturation magnetization was 87.15 emu/g. Their adsorption efficiency for mercury reached 99.1%, and the Hg concentration in wastewater can be decreased from 24.18 to 0.242 μg/L, in accordance with the national discharge standard of China. The saturated adsorbent of Fe 3 O 4 MPMs was regained easily with a magnetic field and reused for 10 times after desorption by 0.1% HNO 3 . The adsorption of Hg 2+ by the MPMs well fitted the Langmuir isotherm model and followed pseudo-second-order kinetics. These results can enable the rational design of MPMs for the treatment of Hg-containing wastewater.

Experimental Research on Mercury-Containing Wastewater in PVC Production by Fly Ash Processing Calcium Carbide Method

To study the removal capacity of modified fly ash in wastewater containing mercury ions under different conditions, the dust from a calcium carbide furnace was added to fly ash, and the pyrogenic process was employed to modify the fly ash. The result indicated that the wastewater had a pH value of 9, the modified fly ash dosage was 0.2 g, the adsorption equilibrium time was 40 minutes, the reaction temperature was 30 °C, and the removal rate could reach 91.9%. Using modified fly ash in polyvinyl chloride production via the calcium carbide method to remove mercury-containing wastewater can help meet the government-prescribed emission standard. This method has advantages such as positive treatment effect, simple operation, and low operating cost.