Actual Plant Conditions Research Articles

Effects of Shaft Tuyere Parameters on Gas Movement Behavior and Burden Reduction in Oxygen Blast Furnace

Parameters of shaft tuyere have vital effects on the gas flow distribution and working condition in the TGR-OBF, which determine the production index, CO2 emission reduction, and economic benefit. To clarify the effects of shaft tuyere parameters on gas movement behavior and burden reduction in oxygen blast furnaces, a 2D steady-state model based on actual plant conditions in China is published in this study. The shaft of the blast furnace can be divided into region I near the wall and region II close to the center, which was influenced by top gas and bosh gas, respectively. The farthest movement distance of the top gas along the radial direction was defined as the penetration depth decided by its kinetic energy ratio. As the height of shaft tuyere decreased from 5/10 L to 1/10 L, the penetration depth decreased from 1.615 m to 1.308 m, and the reduction degree of iron-bearing burden before entering the cohesive zone increased from 0.925 to 0.982. With the shaft tuyere diameters increased from 0.088 m to 0.096 m with a constant blast velocity, the penetration depth was kept elongated at 1.24 m, and the reduction degree before entering the cohesive zone increased from 0.972 to 0.983. While the blast volume of top gas was kept constant, the reduction degree before entering the cohesive zone increased from 0.969 to 0.986. When the shaft tuyere angles increased from −20° to 20°, both the distribution of temperature and CO fraction moved towards the upper shaft slightly, and the penetration depth was kept around 1.24. Under experimental conditions, a low-height shaft tuyere was appropriate for an oxygen blast furnace. Within a certain control range, the changes of shaft tuyere diameters and angles had a small effect on the oxygen blast furnace.

Investigating the Efficiencies of Fusion Algorithms for Accurate Equipment Monitoring and Prognostics

Recent findings suggest the need for optimal condition monitoring due to increasing counter-productive issues ranging from threats to life, malware, and hardware failures. Several prognostic schemes have been reported across many disciplines; however, the issues of sensor data discrepancy emanating from varying loading and operating conditions of cyber-physical system (CPS) components still remain a challenging factor. Nonetheless, a significant part of these prognostic schemes comprises a sensor/feature fusion module for comprehensive health indicator (HI) construction. This study investigates the prowess of unsupervised fusion algorithms for constructing optimal HI construction on two publicly available datasets—a simulated turbofan engine degradation experiment and an actual production plant condition monitoring dataset. The fusion efficiencies of the algorithms were evaluated using standard metrics for prognostic parameter assessments. The results show that the autoencoder is more reliable for real-life applications, including cases with uniform degradation patterns and the more complex scenarios with irregular degradation paths in the sensor measurements/features, and is expected to direct continued research for improved multi-sensor-based prognostics and health management of industrial equipment.

Predicting chattering alarms: A machine Learning approach

Alarm floods represent a widespread issue for modern chemical plants. During these conditions, the number of alarms may be unmanageable, and the operator may miss safety-critical alarms. Chattering alarms, which repeatedly change between the active and non-active states, are responsible for most of the alarm records within a flood episode. Typically, chattering alarms are only addressed and removed retrospectively (e.g. during periodic performance assessments). This study proposes a Machine-Learning based approach for alarm chattering prediction. Specifically, a method for dynamic chattering quantification has been developed, whose results have been used to train three different Machine Learning models – Linear, Deep, and Wide&Deep models. The algorithms have been employed to predict future chattering behavior based on actual plant conditions. Performance metrics have been calculated to assess the correctness of predictions and to compare the performance of the three models.

Development of Air Supply Control Technology in Sidestream MLE Process by Measuring Conductivity

Objectives : This study aimed to achieve improved process performance and energy saving by developing a technology to control the air supply of an aerobic basin by measuring the conductivity in the anoxic basin.Methods : To verify whether conductivity can be used as an operation indicator of biological treatment, the correlation analysis between water quality factor and conductivity of each process was conducted by dividing into summer (methanol input), winter and autumn periods. An empirical formula was presented by briefly arranging the required air quantity formula, and a quick reference was prepared by putting air supply in the conductivity range sequentially. The performance evaluation was judged based on the removal efficiency of ammonia nitrogen and total inorganic nitrogen, SNR and SDNR, the change of air supply, the stability of the process against inflow change.Results and Discussion : The seasonal correlation coefficients of conductivity and water quality items were calculated in the order of ammonia nitrogen, total inorganic nitrogen, DOC, and phosphate in the range of 0.5267 ~ 0.9115. It was found that the conductivity could be used as an operation indicator of the biological treatment process with a correlation coefficient of 0.5 or more. The regression equations for the conductivity and ammonia nitrogen are secured by season, so it is possible to estimate the ammonia nitrogen through the conductivity. At the end of the aerobic basin DO was 3.4 mg/L, the nitrogen treatment efficiency in winter was the best. The aerobic basin DO can be controlled by the air supply, and it can be seen that it is possible to control the air supply and improve the nitrogen treatment efficiency by directly measuring the conductivity having a high correlation with nitrogen. An empirical formula for estimating the required air volume through conductivity and inflow is presented. A' and (B' + X') are 0.0589 (m<sup>3</sup>-air/h)/(m<sup>3</sup>/h)/(μS/cm) and –77.562 (m<sup>3</sup>-air/h)/(m<sup>3</sup>/h). The result of automatic control of air supply according to the measured conductivity of anoxic tank during winter season showed that total inorganic nitrogen removal efficiency and SDNR were 8.3% and 0.007 g-N/g-MLSS/d higher than the actual plant conditions, respectively. During the automatic control period, the air supply/inflow average ratio was 36 (m<sup>3</sup>-air/h)/(m<sup>3</sup>/h), which could reduce the air supply by 21.7% compared to the actual plant conditions.Conclusions : The air supply can be estimated from the flow rate and conductivity. The air supply control technology of the conductivity-based MLE process will be able to simultaneously improve nitrogen removal efficiency and reduce energy consumption.

Study of Calcium Treatment in Steel Ladles for the Modification of Alumina Inclusions to Avoid Nozzle Clogging during Casting

Presence of non-metallic inclusion deteriorates quality of steel and causes nozzle clogging during casting. Nozzle clogging eventually leads to a disruption of normal casting operations. This happens when solid alumina inclusions get accumulate in the nozzle of submerged entry nozzle (SEN). Therefore, it is required to understand the inclusion characteristics (shape, size and chemistry), which forms during the steelmaking process. Calcium is added in the steel ladle furnace (LF) in the form of CaSi wire to modify inclusions and to desulphurize steel. The range in which all the oxides become liquid and no solid sulphides begin to form is regarded as the "optimum window" or “liquid inclusion window” for calcium treatment. It is a target to obtain this calcium addition window, during calcium addition in the ladle furnace. This window mainly depends on the sulfur and total oxygen contents of the liquid steel bath. In the present study, inclusions characteristics such as volume fraction of inclusions, inclusion rating and EDS analysis of inclusions has been carried out using SEM-EDS. Thermodynamic study is carried out using thermodynamic software FACTSAGE and databases to find out formation of various calcium aluminates and the precipitation of CaS. Results show that liquid inclusion window mainly depends mainly on the sulphur level, total oxygen and aluminum content in the steel. These windows will help in calculation of calcium addition range for optimizing the addition of calcium in the ladle. These nomograms have been validated with actual plant condition to reduce the nozzle clogging during continuous casting.

Operator Training Simulator for Ethylene Plant

In a petrochemical plant, training new operators to operate plant safely and consistent is a need. Conventional training for operators relies on senior operators' experience. When experience operator leaves or resigns, it will take longer duration to train new personnel to gain the equivalent experience of previous or senior operators. The operators control the plant by using Distributed Control System (DCS) as an interface and ensure the reliability and productivity of plant sustains. The more challenges they face, the more experience they gain. Most of the operators are trained by real time events they faced on the job but errors or plant upsets should be avoided. It is estimated that in the United States alone, 10 billion USD is lost annually in the process industry caused by errors when faced with plant upsets. Operator training plan is therefore the crucial step to reduce the losses as well as the risk of operating the plant. Operator Training Simulator (OTS) is an alternative solution to safely provide the operators with various realistic operational conditions of the plant, including start-up, shutdown, and emergency conditions. This article discusses on the methodology of building an OTS for Ethylene plant, that are beneficial for educating operator response when faced with critical process upsets and succeeding quicker start-up. A dynamic process model was developed to give accurate dynamic behaviour of the plant process mainly during start-up, shutdown and upset conditions. Testing and verification processes of the models such as Model Acceptance Test (MAT), Factory Acceptance Test (FAT) and Site Acceptance Test (SAT) were deliberated. Few issues or problems faced during the testing were also discussed. Based on the experience of developing the simulator, process model was developed using mass and energy balance method does not reflect the actual plant conditions. It might be suitable for commissioning a new plant. However, once the plant is started all the parameters need to be realigned to meet the actual plant data. Process model for existing plant should always apply the actual plant data as a primary data. Especially during MAT, FAT and SAT processes, experience of the panel man is the best input data to get the best output of the simulations.

Simulation and Analysis of Small Break LOCA for AP1000 Using RELAP5-MV and Its Comparison with NOTRUMP Code

Many reactor safety simulation codes for nuclear power plants (NPPs) have been developed. However, it is very important to evaluate these codes by testing different accident scenarios in actual plant conditions. In reactor analysis, small break loss of coolant accident (SBLOCA) is an important safety issue. RELAP5-MV Visualized Modularization software is recognized as one of the best estimate transient simulation programs of light water reactors (LWR). RELAP5-MV has new options for improved modeling methods and interactive graphics display. Though the same models incorporated in RELAP5/MOD 4.0 are in RELAP5-MV, the significant difference of the latter is the interface for preparing the input deck. In this paper, RELAP5-MV is applied for the transient analysis of the primary system variation of thermal hydraulics parameters in primary loop under SBLOCA in AP1000 NPP. The upper limit of SBLOCA (10 inches) is simulated in the cold leg of the reactor and the calculations performed up to a transient time of 450,000.0 s. The results obtained from RELAP5-MV are in good agreement with those of NOTRUMP code obtained by Westinghouse when compared under the same conditions. It can be easily inferred that RELAP5-MV, in a similar manner to RELAP5/MOD4.0, is suitable for simulating a SBLOCA scenario.

福島第一原子力発電所燃料デブリ取出し工法に係る炉内熱流動評価解析

Removal of molten fuel debris accumulated in Units 1 to 3 of Fukushima Daiichi Nuclear Power Plant must be completed in order to deal start the decommissioning process. Several methods are proposed to remove the fuel debris from PCV/RPV, and it is essential to perform safety assessment for all the possible scenarios. In the present study, numerical model to investigate the three-dimensional distribution of in-vessel heat transfer characteristics of the actual plant condition is developed. The simulation results obtained from the commercial CFD code, STARCCM+, is compared with the actual plant data taken by Tokyo Electric Power Company to verify the validity of the current analysis. Following the confirmation of the model's validity, the numerical analysis was carried out to investigate the expected conditions during “dry method” in 2021, which marks 10 years from the accident.

Computer Simulation on Reaction Condition when Vinyl Acetate is Compound by Acetic Acid and Acetylene in Fixed Bed Reactor

The macro-dynamics for synthesis of vinyl acetate on Zn(Ac)2—acticarbon catalyst was studied. Consulting actual plant conditions by means of computer simulation, the parameters and reaction conditions for a fixed bed reactor used to produce vinyl acetate in acetylene method were calculated. The result shows that total heat transfer coefficient between catalyst bed and heat conductive oil could be affected by variety of conditions: catalyst diameter, airspeed, temperature and speed of heat conductive oil, and tube diameter in reactor. Analyzing the principles about how the factors affect the heat conduction, a laboratory reactor was made according to the analogue data. The actual temperature distribution of catalyst bed could inosculate with the analogue results roughly.

Effect of concentrate recycle on anti-scalant performance

A convenient reverse osmosis (RO) laboratory technique for rapid initial screening of anti-scalant performance is based on full recycling of concentrate and permeate to the feed vessel and observing the scale suppression effectiveness under different operating conditions. Once-through flow tests in which both permeate and concentrate are continuously withdrawn from the RO system simulate more closely actual plant conditions but are usually impractical as they require a large inventory of the feed solution. In the recycle mode of operation, the residence time of the anti-scalant in the system is increased. The objective of the present study was to investigate if the increased residence time leads to a deviation between results measured by the simple recycle technique with those obtained by the more elaborate once-through technique. A comparison between inhibition results observed in full recycle and once-through tests respectively was carried out in a continuous flow pilot RO system. Tests were performed w...

Pathways from laboratory to full scale carbon capture—Technology demonstrations in plant settings

Abstract The Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) was setup with distinct programs focusing on storage, capture, demonstration, education and international collaboration designed to address the many issues facing potential carbon capture and storage (CCS) projects. In particular the Capture Program aims to research, develop and deploy technologies that can achieve significant cuts in capture cost (75%–80%) and provide Australia with a research and education capability to support industries using these technologies. This paper provides details on the capture research activities within the centre, the major demonstration projects underway, including outlines of the equipment employed and how they are enabling the progression of separation technologies from laboratory through to eventual large scale commercial operation. Aided by recent initiatives of the Victorian State Government, under their Energy Technology Innovation Strategy (ETIS) program, CO2CRC is leading the research in two such research and development projects. These three year projects, one a $6 million post combustion demonstration incorporating a 10,000 tpa CO 2 capture plant, and the other a $5.5 million pre-combustion application, each designed to test the CO2CRC’s full range of capture technologies (solvents, membranes and adsorption systems), in purpose built rigs under actual power plant conditions. The ability to demonstrate both conventional and novel capture techniques in the one facility is, we believe, unique.

One-component silicon adhesives-sealants

One-component adhesives-sealants, mechanisms of their synthesis and cure, the most important fields of their application, and peculiarities of their production under actual plant conditions are described. The assortment of domestic adhesives-sealants and their main developers and producers are reported. The most important parameters of the properties of domestic one-component adhesives-sealants, Elastosil, Pentelast, Avtogermesil, and other grades, are discussed.

A simulation of a steam generator tube rupture in a VVER-1000 plant

In the operation of nuclear power plants, it is very important to evaluate different accident scenarios in actual plant conditions. One of the main accidents is steam generator tube rupture (SGTR), in the field of nuclear safety. In this research the variation of thermo-hydraulics parameters in a primary loop under SGTR accidents at Bushehr VVER-1000 Nuclear Power Plant (NPP) is analyzed by RELAP5/MOD 3.2 thermo-hydraulics code. A model of Bushehr unit 1 has been developed based on RELAP5/MOD 3.2 at Shiraz University in Iran. The results obtained by this code are compared with the Preliminary Safety Assessment Report (PSAR) data of Bushehr NPP. The DINAMICA-97 code was used to evaluate the SGTR accident in Bushehr PSAR by Federal Agency on Nuclear Energy of Russia. In simulation of this accident, it was supposed that after the establishment of a steady-state condition in the system, primary-to-secondary coolant leakage is as a result of an instantaneous break happened with equivalent diameter of 100 mm in the area of lower row heat exchanging tubes in one of the fourth steam generators (SG#2). Loss of off-site power and two diesel generators of in-site power in loops 1and 2 of the primary cycles follow this event. The results show that after initiating the accident, the pressure above the core decreases rapidly from 16 MPa to 8 MPa during 130 s and finally, it will stabilize to about 7.1 MPa and it becomes practically equal to the secondary pressure and it leads to stop leakage completely at the end of transient. The coolant temperature at the reactor inlet decreases from 566 K to 473 K during the transient time and the cooldown of the coolant of the primary loop is performed. The primary-to-secondary coolant leakage reduces from 800 kg/s to approximately 0.0 kg/s during the first 150 s of the accident. As seen from the results, the thermo-hydraulics code correctly predicts the behavior of the main plant parameters in comparison with the reported PSAR data.

Effect of Combined Loading Due to Bending and Internal Pressure on Pipe Flaw Evaluation Criteria

Considering a rational maintenance rule of Light Water Reactor piping, reliable flaw evaluation criteria are essential to determine how a detected flaw is detrimental to continuous plant operation. Ductile fracture is one of the dominanant failure modes to be considered for carbon steel piping, and can be analyzed by the elastic-plastic fracture mechanics. Some analytical efforts have been provided as flaw evaluation criteria using load correction factors such like the Z-factors in the JSME codes on fitness-for-service for nuclear power plants or the ASME boiler and pressure vessel code section XI. The present correction factors were conventionally determined taken conservatism and simplicity into account, however, the effect of internal pressure which would be an important factor under an actual plant condition was not adequately considered. Recently, a J-estimation scheme, “LBB. ENGC” for ductile fracture analysis of circumferentially through-wall-cracked pipes subject-ed to combined loading was newly developed to have a better prediction with more realistic manner. This method is explicitly incorporated the contribution of both bending and tension due to internal pressure by means of the scheme compatible with an arbitrary combined loading history. In this paper, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. A correction factor based on the new J-estimation scheme was compared with the present correction factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of internal pressure.

Effect of Combined Loading Due to Bending and Internal Pressure on Pipe Flaw Evaluation Criteria

Considering a rational maintenance rule of Light Water Reactor piping, reliable flaw evaluation criteria are essential to determine how a detected flaw is detrimental to continuous plant operation. Ductile fracture is one of the dominanant failure modes to be considered for carbon steel piping, and can be analyzed by the elastic-plastic fracture mechanics. Some analytical efforts have been provided as flaw evaluation criteria using load correction factors such like the Z-factors in the JSME codes on fitness-for-service for nuclear power plants or the ASME boiler and pressure vessel code section XI. The present correction factors were conventionally determined taken conservatism and simplicity into account, however, the effect of internal pressure which would be an important factor under an actual plant condition was not adequately considered. Recently, a J-estimation scheme, “LBB. ENGC” for ductile fracture analysis of circumferentially through-wall-cracked pipes subject-ed to combined loading was newly developed to have a better prediction with more realistic manner. This method is explicitly incorporated the contribution of both bending and tension due to internal pressure by means of the scheme compatible with an arbitrary combined loading history. In this paper, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. A correction factor based on the new J-estimation scheme was compared with the present correction factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of internal pressure.

Design of mixture de-noising for detecting faulty bearing signals

Detecting the waveform of a noisy signal is a key problem in the detection of early bearing faults under actual plant conditions. Mixture de-noising is found to be a useful technique for identifying bearing signals and greatly improves the fault diagnostics of the bearings. The mixture de-noising technique consists of an adaptive noise-canceling filter and a wavelet-based de-noise estimator. The mixture de-noising technique can substantially improve the signal-to-noise ratio when the signal is contaminated by noise. The performance of mixture de-noising under different noise ratios, bearing failure sizes and shaft speeds are discussed in this paper. This paper shows that the diagnostic role of failure diagnosis and analysis techniques can be made more effective with the application of mixture de-noising.

ICONE11-36136 Program of in-pile IASCC testing under the simulated actual plant condition : Development of Technique for In-pile IASCC Initiation Test in JMTR

Irradiation assisted stress corrosion cracking (IASCC) is caused by the synergistic effects of neutron irradiation, stress and corrosion by high temperature water. It is, therefore, essential to perform in-pile SCC tests, which are material tests under the conditions simulating those of actual LWR operation, in order to clarify the precise mechanism of the phenomenon, though mainly out-of-pile SCC tests for irradiated materials have been carried out in this research field. There are, however, many difficulties to perform in-pile SCC tests. Performing in-pile SCC tests, essential key techniques must be developed. Hence as a part of development of the key techniques for in-pile SCC tests, we have embarked on development of the test technique which enables us to obtain the information concerning the effect of such parameters as applied stress level, water chemistry, irradiation conditions, etc. on the crack initiation behavior. Although it is difficult to detect the crack initiation in in-pile SCC tests, the crack initiation can be evaluated by the detection of specimen rupture if the cross section area of the specimen is small enough. Therefore, we adopted the uniaxial constant loading (UCL) test with small tensile specimens. This paper will describe the current status of the development of several techniques for in-pile SCC initiation tests in JMTR and the results of the performance tests of the designed testing unit using the out-of-pile loop facility.

ICONE11-36106 Program of in-pile IASCC testing under the simulated actual plant condition : Thermohydraulic design study of saturated temperature capsule for IASCC irradiation test

ICONE11-36106 Program of in-pile IASCC testing under the simulated actual plant condition : Thermohydraulic design study of saturated temperature capsule for IASCC irradiation test

ICONE11-36324 Program of in-pile IASCC testing under the simulated actual plant condition : Overview

ICONE11-36324 Program of in-pile IASCC testing under the simulated actual plant condition : Overview

Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX).

To investigate the dechlorination of fly ash during low-temperature treatment under oxygen-deficient conditions (thermocatalyic treatment or Hagenmaier process), six fly ash samples from six different incineration plants were treated in a laboratory experiment or in the actual plant, either under ideal (400 degrees C, 120 min) or intermediate (300 degrees C, 30 min) conditions. The aim of the present study was to confirm the decrease in the I-TEQ (international toxicity equivalency) of polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs) and coplanar polychlorinated biphenyls (co-PXBs) and, also for the first time, the decrease in the sum of dioxin-like toxicity (bioassay- or bio-TEQ) of all kinds of other dioxin-like Ah receptor agonists (such as PXDD/Fs, PXBs, PXN, X = Br, F) measured by two state-of-the-art cell-based Ah receptor-dependent bioassays: H4IIE-Ethoxy-Resorufin-o-Deethylase (EROD) and H4IIE-luc/DR-Chemical Activated Luciferase expression (DR-CALUX). The treatment efficiency was calculated on the basis of the reduction in the I-TEQ and bio-TED values. For these fly ash samples, the treatment efficiency, as measured by chemical analysis, was higher than 99%, and 85%-99%, in the case of the bio-TED values, indicating that these Ah receptor binding toxic compounds were sufficiently decomposed. Bio-TEQ values for untreated fly ash samples (n = 6) were on average 1.2 times (range 0.7-1.9), for the H4IIE-EROD assay, and 2.8 times (1.1-4.9), for the DR-CALUX assay, higher than I-TEQ values measured by chemical analyses (sum of PCDD/Fs and co-PCBs). In the case of these fly ash samples treated under ideal conditions and therefore low in contaminants, the bio-TEQ values were on average 1.4 times (range 0.9-1.8), for the H4IIE-EROD assay, and 5.1 times (range 1.2-12), for the DR-CALUX assay, higher than the I-TEQ values.