Chlorine Flow Research Articles

Studi Performa Cooling Tower berdasarkan Kualitas Air Pendingin

Cooling water is used to cool fluids with a high temperature in a closed system, such as a cooling tower or heat exchanger. Sometimes, the cooling water is specified in a long tube, which risks fouling and rusk. This research will study cooling water quality as Total Dissolved Solid (TDS), chlorine concentration, and antiscale. In the design of the cooling tower at PLTGU Tanjung Uncang, the range or limit of the permitted TDS is 50,000. If this figure has been reached, the cooling tower must be blown down. Blowdown is water in the cooling tower that is deliberately removed to avoid the concentration of impurities during heat evaporation. At PLTGU Tanjung Uncang, the permitted chlorine concentration is in the range of 0.2-0.5. Chlorine flow in the cooling tower at PLTGU Tanjung Uncang is reversed with Cl concentration and TDS. Inject Antiscale aims to maintain cooling tower performance, which aims to be anti-rust.

Time dependent analysis of lateral bearing capacity of reinforced concrete piles combined with corrosion and scour

This study investigates the effect of chlorine corrosion and flow scour on the lateral bearing capacity of piles. A chloride diffusion model was established to obtain the initial corrosion time of reinforcement based on Fick's second law. The degradation of stiffness after corrosion is represented by a reduction coefficient. The finite difference method is used to solve the deflection differential equation of laterally loaded piles. The maximum scouring depth of piles in cohesive soil and the variation of scouring depth with time are calculated by empirical model. The calculated results from the analytical solution revealed that the pile stiffness decreases with the exposure time. As the time increase, the lateral displacement and shear force decrease on the other hand the bending moment increases. The increase of flow velocity and pile diameter results in the increase of the maximum scour depth around the pile. The bending moment, shear force, and lateral displacement of piles after scour increase significantly compared to the lateral bearing performance of piles before scour.

A data-driven model for the prediction of chlorine losses in water distribution trunk mains

A data-driven model that uses 4 different machine learning (ML) algorithms (Feed forward artificial neural networks (ANN), Nonlinear autoregressive exogeneous (NARX) ANN, support vector machine and Random Forest) was designed for the prediction of chlorine loss events in water distribution trunk mains. The model, firstly, identifies past chlorine loss events and their associate flow or temperature events. Then, the detected past flow events and their associate past chlorine loss events are used to train the ML algorithms. The model was tested in 3 trunk mains of the same drinking water distribution system with similar diameter but with different characteristics, using each time a different combination of parameters (flow (input) - past chlorine losses (output) or flow, temperature, and chlorine (input) - past chlorine losses (output)) and machine learning algorithms. Results indicate that the model could predict a future chlorine loss event with a period between 2 to 10 hours depending on the parameter and ML algorithm used and the trunk mains’ hydraulic characteristics.

Co-chlorination of low-density polyethylene in paraffin: An intensified green process alternative to conventional solvent-based chlorination

Abstract This study experimentally demonstrates the potential of co-chlorination as a green process alternative to conventional independent chlorination of polyolefins, which involves the use of non-environment-friendly solvents like carbon tetrachloride (CCl4). Low-density polyethylene (LDPE) was used as a representative polymer in this study and co-chlorinated with paraffin. Apart from being a reactant, the paraffin also acts as a solvent, thus eliminating the need for using CCl4 during the reaction. Test runs were first conducted to measure LDPE-paraffin solution viscosities at different LDPE concentrations to investigate the solubility of LDPE in paraffin. Co-chlorination experiments were then carried out covering a range of temperatures (100–130°C), chlorine flow rates (150–350 mL·min−1), LDPE concentrations in paraffin (10–30%) and agitation speeds (100–400 rpm). The chlorinated LDPE and paraffin products were subsequently characterized post separation using FTIR/1H NMR spectroscopy and differential scanning calorimetry. Specific properties of these two co-chlorinated products were compared with independently chlorinated LDPE and paraffin. The co-chlorinated products were found to compare well in terms of chlorine content and quality. A preliminary comparative study from a process perspective between co-chlorination and conventional chlorination of LDPE is also reported. The results obtained confirm the potential of co-chlorination as an environmentally friendly alternative.

High Energy and Low-Cost Membrane-Free Chlorine Flow Battery

Grid-scale energy storage is essential for reliable electricity transmission and renewable energy integration. Redox flow batteries (RFB) provide affordable and scalable strategies for stationary energy storage. But most of the current RFB chemistries are based on expensive transition metal ions or synthetic organics. Here, we report a reversible Cl2/Cl- redox flow battery through electrolysis of aqueous NaCl electrolyte, the as-produced Cl2 is stored and extracted using carbon tetrachloride (CCl4) or mineral spirit flow. The immiscibility between the CCl4 and NaCl electrolyte enables a membrane-free design with energy efficiency of >91 % and energy density of 125.7 Wh/L. With the inherently low cost of active materials (~5 $/kWh) and highly reversible redox reaction of Cl2/Cl-, the chlorine flow battery leaves significant space to meet the stringent price and reliability target for stationary energy storage. Figure 1

High-energy and low-cost membrane-free chlorine flow battery

Grid-scale energy storage is essential for reliable electricity transmission and renewable energy integration. Redox flow batteries (RFB) provide affordable and scalable solutions for stationary energy storage. However, most of the current RFB chemistries are based on expensive transition metal ions or synthetic organics. Here, we report a reversible chlorine redox flow battery starting from the electrolysis of aqueous NaCl electrolyte and the as-produced Cl2 is extracted and stored in the carbon tetrachloride (CCl4) or mineral spirit flow. The immiscibility between the CCl4 or mineral spirit and NaCl electrolyte enables a membrane-free design with an energy efficiency of >91% at 10 mA/cm2 and an energy density of 125.7 Wh/L. The chlorine flow battery can meet the stringent price and reliability target for stationary energy storage with the inherently low-cost active materials (~$5/kWh) and the highly reversible Cl2/Cl− redox reaction.

Potentiometric Free Chlorine Detection without Using Conventional Reference Electrodes

Introduction Chlorine disinfection of water is one of the treatment methods to supply safe drinking water. The concentration of free chlorine has to be monitored as an important index to make the process efficient and is generally measured at several points in the pipeline system between water treatment plant and the water taps. For realizing smart water supply system based on various IoT technologies, low cost and maintenance-free type sensor which can be easily applied to pipeline network system would be effective.Various kinds of analytical techniques for detection of free chlorine concentration have been proposed and practically utilized. Comparing with regent-type colorimetric methods, electrochemical methods are suitable for in-line monitoring with simplicity and low cost. So far, many amperometric sensors have been proposed [1, 2], Recently, the authors reported a simple sensor device which is composed of two dissimilar electrodes [3]. The open circuit potential of each electrode has a different sensitivity to free chlorine and then the differential signal is extracted as sensor output. In this study, sensing characteristics of this sensor device in flowing-tap-water system were evaluated. Principle The schematic diagram of simple two-electrode system to enable in-line monitoring of free chlorine concentration is represented in Fig.1. Ideally, the sensor device consists of detecting and compensating metal electrodes that are active and inactive to free chlorine as target compound, respectively. Furthermore, sensitivities to interferences, such as temperature, pressure, pH, conductivity, and so on, have to be almost same in order to self-compensate the fluctuation of various environmental factors. In our previous study [3], it was found that platinum and SUS316 electrode are suitable for detecting and compensating electrode, respectively. The difference in open circuit potential could be explained by mixed potential theory. This passive-type sensor which utilize its electromotive force between dissimilar electrodes would have many advantages of low cost, low power consumption and these features enable long-term use of sensor device without periodical maintenance. Method Pt and SUS316 were used as test electrodes. These metal rods were embedded in center of a Teflon mold. Prior to use, each electrode surface was polished with SiC paper and ultrasonically rinsed with ethanol. In order to validate the sensor performances of Pt-SUS316 pair of electrodes in flowing-tap-water system, these electrodes were directly inserted in pipeline, as shown in Fig. 1. Practical tap water with or without free chlorine was fed into this test pipeline at various flow rate by using activated carbon filter which can selectively remove free chlorine. The differential open circuit potentials of Pt-SUS316 pair were measured using a high-input impedance electrometer. The concentration of residual chlorine was checked by free chlorine portable photometer based on DPD method. Results and Conclusions As a first step, the baseline drift behavior of Pt-SUS316 electrode pair was checked, as shown in Fig. 2. Baseline drift was defined as the variation in sensor output from that at the start time of each experiment. Although a slight baseline drift was observed, the value of the drifts were within the range of ±10 mV. However, trend of the drift could not be clarified. It would be caused by tiny fluctuation of environmental conditions such as temperature, pH, etc.Typical sensor performance in flowing-tap-water system was described in Fig. 3. Potential difference (sensor output) between Pt and SUS316 was around 150 mV in practical tap water without free chlorine. It indicates that open circuit potential of Pt was higher than that of SUS316 under this condition. When the flow experiment started, the baseline level was slightly fluctuated. After the level was stabilized, tap water containing free chlorine (0.6 mg/L) flow thorough the test pipeline. The sensor output sharply increased and reached to steady state within 10 min. This large response was mainly attributed to high sensitivity of Pt to free chlorine. Therefore, concentration of free chlorine could be monitored under in-line condition without using conventional reference electrodes. On the other hand, recovery rate was very slow and seem to become slower. However, reproducibility of the sensor response with repeated exposure to free chlorine was good since the steady state values almost unchanged.

Characteristics of scales and their impacts on under‐deposit corrosion in an oil production well

AbstractThis study examined the composition and characteristics of scales formed at different depths in an oil production well, which had developed over years of well operation, workovers, and interventions, by the combined use of optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, and X‐ray diffraction. The iron‐rich scales consist of several mineral phases, including a dominant portion of akagneite and hibbingite, some barite, silicon dioxide, copper sulfide, and small amounts of iron oxide and calcium carbonate. The scales typically have a layered structure consisting of five to six distinct layers, which impacts steel corrosion processes. The type of corrosion beneath the scale surface was found to be diversified. Pitting morphology corresponding to different stages in the development of scales was observed. The relation between pitting density and the extent of corrosion was analyzed. The effects of environmental factors, including calcium, chlorine, oxygen content, steel microstructure, and multiphase flow, on scale formation and corrosion mechanisms, were discussed. The results provide important insights into the formation of scales and the under‐deposit corrosion processes in the oil production tubes.

Potentiometric Free Chlorine Detection without Using Conventional Reference Electrodes

Introduction Water chlorination is one of key process for supplying safe drinking water. The concentration of fee chlorine has to be monitored as an important index to make the process efficient and is mainly measured at water treatment plant. For realizing smart water supply system based on various IoT technologies, low cost and maintenance-free type sensor which can be easily applied to whole pipeline network system including water outlet on every home would be required. Various kinds of analytical techniques for detection of free chlorine concentration have been proposed and practically utilized. Comparing with regent-type colorimetric methods, electrochemical methods are suitable for in-line monitoring with simplicity and low cost. So far, many amperometric sensors have been proposed [1, 2], Recently, the authors reported a simple sensor device which is composed of two dissimilar electrodes [3]. The open circuit potential of each electrode has a different sensitivity to free chlorine and then the differential signal is extracted as sensor output. In this study, sensing characteristics of this sensor device in flowing-tap-water system were evaluated. Principle The schematic diagram of simple two-electrode system to enable in-line monitoring of free chlorine concentration is represented in Fig.1. Ideally, the sensor device consists of detecting and compensating metal electrodes that are active and inactive to free chlorine as target compound, respectively. Furthermore, sensitivities to interferences, such as temperature, pressure, pH, conductivity, and so on, have to be almost same in order to self-compensate the fluctuation of various environmental factors. In our previous study [3], it was found that platinum and SUS316 electrode are suitable for detecting and compensating electrode, respectively. The difference in open circuit potential could be explained by mixed potential theory. This passive-type sensor which utilize its electromotive force between dissimilar electrodes would have many advantages of low cost, low power consumption and these features enable long-term use of sensor device without periodical maintenance. Method Pt and SUS316 were used as test electrodes. These metal rods were embedded in center of a Teflon mold. Prior to use, each electrode surface was polished with SiC paper and ultrasonically rinsed with ethanol. In order to validate the sensor performances of Pt-SUS316 pair of electrodes in flowing-tap-water system, these electrodes were directly inserted in pipeline, as shown in Fig. 1. Practical tap water with or without free chlorine was fed into this test pipeline at various flow rate by using activated carbon filter which can selectively remove free chlorine. The differential open circuit potentials of Pt-SUS316 pair were measured using a high-input impedance electrometer. The concentration of residual chlorine was checked by free chlorine portable photometer based on DPD method. Results and Conclusions As a first step, the baseline drift behavior of Pt-SUS316 electrode pair was checked, as shown in Fig. 2. Baseline drift was defined as the variation in sensor output from that at the start time of each experiment. Although a slight baseline drift was observed, the value of the drifts were within the range of ±20 mV. However, trend of the drift could not be clarified. It would be caused by tiny fluctuation of environmental conditions such as temperature, pH, etc. Typical sensor performance in flowing-tap-water system was described in Fig. 3. Potential difference (sensor output) between Pt and SUS316 was around 200 mV in practical tap water without free chlorine. It indicates that open circuit potential of Pt was higher than that of SUS316 under this condition. When the flow experiment started, the baseline level was slightly fluctuated. After the level was stabilized, tap water containing free chlorine (0.6 mg/L) flow thorough the test pipeline. The senor output sharply increased and reached to steady state within 10 min. This large response was mainly attributed to high sensitivity of pt to free chlorine. Therefore, concentration of free chlorine could be monitored under in-line condition without using conventional reference electrodes. On the other hand, recovery rate was very slow and seem to become slower. However, reproducibility of the sensor response with repeated exposure to free chlorine was good since the steady state values almost unchanged.

Reducing Water Losses for Sustainable Urban Development

From the point of view of water supply systems, and in particular of distribution networks, the environmental, social and economic criteria have had a significant role in the selection of urban water development decisions. In this respect, the article addresses the issue of reducing water losses in drinking water supply systems. Thus, there are presented the methods and technologies used and studied, currently, for the detection of damages on the pipes of the distribution networks. Continuous monitoring of the pipeline network has become an integral part of drinking water supply systems. Remote data transmission and the use of professional software allows for accurate loss detection in places where the probability of loss is maximum. The relocation method has the benefit of economies of time and money. In most developed countries, the percentage of water loss is significant. The article makes a theoretical analysis on the application of non-revenue water loss solutions (NRW) in Timisoara, Romania. At various points in the drinking water distribution network, measuring points are installed to measure the pressure, residual chlorine concentration, flow rate and flow direction. Measurement panels installed in underground fireplaces and sensors mounted directly on pipes transmit the measured data from sensors directly to the dispatcher via the GPRS data service. In addition to this information, the measurement point also generates alarms in the event of a home flood, unauthorized access, or lack of power from the grid. The results of the analysis highlight the fact that the loss reduction is quantified in water savings with positive effects on the reduction of pressure on the existing networks.

Carbon derived from silicon carbide fibers, a comparative study

SiC-based fibers, eleven in total, derived from polycarbosilane pyrolysis and belonging to the three different generations, were fully converted into microporous carbon after selective etching of silicon atoms under pure chlorine flow at intermediate temperatures (550–850 °C). In this work, relationship between as-received fibers and their subsequent carbide-derived carbon (CDC) properties, pore structure oxidation resistance and mechanical properties, was investigated. The resulting carbon is microporous or micro-mesoporous with equivalent specific surface area exceeding 1000 m2 g−1 and pore size distribution (PSD) related to the substrate chemical composition and microstructure of former fibers. Oxidation kinetics were found to depend on this PSD. The former sp2 carbon free network of fibers remained unaffected by the chlorination. Its amount and percolation were respectively correlated to Young modulus and tensile strength of CDC. This carbon thus displays a nano-composite-like behavior with a former etched carbide matrix (transformed SiC and SiCO) and carbon free reinforcement. The results demonstrate CDC allows the control over pore size and mechanical properties by selecting an appropriate multiphasic substrate, combining etched and non-etched compounds.

Interplay of factors involving chlorine dose, turbidity flow capacity and pH on microbial quality of drinking water in small water treatment plants

In an endeavour to ascertain the interplay of factors involving chlorine dose, turbidity and flow capacity on microbial quality of drinking water in small water treatment plants (SWTPs), data from a previous study were analysed. The findings showed that most of the SWTPs were not producing water of safe microbial quality. Fifty one percent (51%) and seventy three (73%) of the SWTPs were below the stipulated limits for residual chlorine in final water and water at the point of use respectively. Current flow capacity was a major determinant of the microbial water quality indicators but no association was found between the dose of chlorine used for water treatment and the microbial water quality indicators. However, a combination of the amount of chlorine dose used up during treatment, flow capacity and change in turbidity contributed to about 65% of the amount of heterotrophic plate counts removed from raw water. Current flow capacity contributed less than 14% of the variation in chlorine dose used in water treatment at the plants. Turbidity tended to correlate and contribute more to the prediction of total coliform counts while faecal coliform counts were determined by current flow capacity and conductivity. Treatment plants with current flow capacity of over 50 Ml / d tended to be more efficient in heterotrophic plate count removal. In conclusion, this study noted that most of the SWTPs were using a chlorine dosage that was below the amount required by their respective current flow capacity; possible micro-organism resistance to chlorine and the significant effect of the level of turbidity on the microbial quality of treated water.

Degradation of chloramphenicol by chlorine and chlorine dioxide in a pilot-scale water distribution system

This paper presents the degradation of chloramphenicol (CAP) by chlorine and chlorine dioxide (ClO2) in tap water in a pilot-scale water distribution system (WDS) containing loops of three different pipe materials (stainless steel, ductile iron, and polyethylene). Greater degradation of CAP was seen with chlorine than with chlorine dioxide. After 180 min in the ductile iron loop of the WDS, the percent degradation of CAP by 2.0 mg/L of chlorine or ClO2 was 76% and 52%, respectively. The degradation of CAP by chlorine in the WDS was investigated under various conditions, including chlorine concentrations of 1.0–4.0 mg/L, and varying pipe materials, flow velocity, and temperature. Degradation of CAP under different conditions could be fitted by first-order kinetics, and the determined first-order rate constants (k, min−1) increased with an increase in chlorine concentration, flow velocity, and temperature. The degradation of CAP in different pipes followed the order stainless steel loop > ductile iron loop > polyethylene loop. Identified oxidized products of the chlorination of CAP were in agreement with proposed reaction pathways, which were also theoretically confirmed by quantum chemical calculations. Formation of three disinfection byproducts (chloroform, bromodichloromethane, and dibromochloromethane) was observed, with increases of 7.7, 0.76, and 0.39 µg/L, respectively, after 160 min.

Microstructure and deposition kinetics of Nb prepared by chemical vapor deposition

The deposition kinetics and microstructure of chemical vapor deposition (CVD) of Nb on the Mo substrate at different deposition variables is investigated. The morphology of CVD Nb is columnar, it exhibits a strong preferred orientation and its growth direction is perpendicular to the substrate surface, the deposition rate and grain size increased with the increase of deposition temperature. The deposition rate conforms to the Arrhenius formula, the activation energy [Formula: see text] at high temperature and low temperature is 0.85 kJ/mol and 7.2 kJ/mol, respectively. The rate-limiting step for CVD Nb at high temperature is chemical reaction step, whereas that is the mass transport step at low temperature. Chlorination temperature has a weak influence on deposition rate and grain structure, the deposition rate and grain size of CVD Nb increased with the increase of the chlorine flow and hydrogen flow, the maximum deposition rate is [Formula: see text], thus, the optimum deposition temperature is 1200[Formula: see text]C, chlorination temperature is 350[Formula: see text]C, hydrogen flow is 400 ml, chlorine flow is 200 ml.

Factors affecting the performance and monitoring of a chlorine wash in preventing Escherichia coli O157:H7 cross-contamination during postharvest washing of cut lettuce

This study examined factors that may affect the performance of a produce wash in preventing E. coli O157:H7 cross-contamination. Fresh-cut romaine lettuce (8 or 20 g) inoculated with ca. 7 log CFU/g of E. coli O157:H7 expressing green fluorescence protein was washed with uninoculated cut lettuce (800 or 2000 g) in 40 L of water for 2 min. Washing trials were performed in both sterile tap water and spent wash water collected from a commercial leafy greens processing facility under different prewash free chlorine levels (0, 5, 20 and 30 ppm), water temperatures (3 and 20 °C), leaf-to-water ratios (1:20 and 1:50), and flow rates (fast, medium, and slow). Performance of the chlorine wash was greatly affected by free chlorine level and wash water quality. Temperature, lettuce-to-water ratio, or water flow rate did not appear to have a significant impact. A prewash free chlorine concentration of 10 or 20 ppm was effective in preventing E. coli O157:H7 cross-contamination when lettuce was washed in tap water in the two washing systems assembled; 30 ppm of chlorine was needed to prevent cross-contamination during washing in industry water. Small-scale (100 ml) inactivation studies were performed to examine the impact of organic and solid contents (with the addition of lettuce juice and play sand) on the antimicrobial efficacy of chlorinated water. Increases in organic matter resulted in greater depletion of chlorine and the presence of solids enabled the pathogen to better survive chlorination; both led to a lower antimicrobial efficacy observed. ORP did not correlate linearly with free chlorine. E. coli O157:H7 cross-contamination was observed when ORP exceeded 650 mV, indicating that a threshold level of 650 mV may not ensure the safety of produce wash water. Since effective chlorine level is highly influenced by wash water quality, monitoring of produce washing systems may best be performed by measuring wash water quality in conjunction with rapid measurement of free chlorine.

Online Monitoring of Wastewater Effluent Chlorination Using Oxidation Reduction Potential (ORP) vs. Residual Chlorine Measurement

Various control strategies are employed to insure that sufficient amount of chlorine has been applied to the wastewater effluent to achieve desired disinfection goals. In the commonly used control strategies, such Feed Back Control and Compound Loop Control, the combination of effluent flow rate, chlorine flow rate and chlorine residual are measured for dosing control with the chlorine residual used as a set point parameter. Recently Oxidation-Reduction Potential (ORP) has been employed as a control measurement and set point parameter for effluent chlorine dosing control as well. Theoretically, use of chlorine residual or ORP set point makes the chlorine dosing possible to simultaneously respond to changes in effluent flow rate and in process (such as fluctuating effluent ammonia levels), which cause variations in chlorine demand and thus the ORP or chlorine residual after the dose point. This would also potentially reduce chlorine feed requirements. Specific ORP or residual chlorine residual levels to ensure effective disinfection could be effectively monitored and maintained under changing effluent quality conditions. In addition, immediate detection of chlorine feed malfunction could be achieved when analyzers are employed at the chlorine dosing point.This title belongs to WERF Research Report SeriesISBN: 9781843397175 (eBook)

Investigation of chloride deposit formation in a 24 MWe waste to energy plant

Waste-to-energy (WTE) plants are widely utilized for the production of heat and electricity from municipal solid waste (MSW) and refuse-derived fuel (RDF). However, there is the potential for high temperature corrosion to occur on the heat transfer surface due to a high chlorine content (0.5–1.0wt.%) in MSW. Therefore, a full scale investigation was conducted in a WTE plant located in Tianjin, China, to study the corrosion mechanism and deposit chemistry that occurs during engineering projects. Deposit and corrosion probes were inserted and exposed to flue gas at five different locations for nine months then two different alloy probes were removed and analyzed. The chlorine flow in the incinerator was also investigated via stack sampling and the analysis of the composition of the residual. The results demonstrate that fly ash dominates the output for chlorine mass flow, accounting for 40.3% of total chlorine. Bottom ash accounts for approximately 6.7%, semi-dry scrubber and bag filter ash 31.4%, stacks 2.75% and leachate 18.6%. Using the back-calculation method, the chlorine content is 0.92wt.% which is consistent with the elemental analysis that considers alkali salts soluble in the leachate resulting from MSW storage prior to boiler combustion. All deposits have a high concentration of sulfur and calcium but the potassium and chlorine concentrations suddenly decrease with flue gas flow. The deposit growth can be classified into three layers: the outer layer, the inner layer and the interface. The sodium and sulfur contents are high in the interface while the silicon and magnesium are high in the inner layer and calcium and chlorine are considerably high in the outer layer. The results are valuable for a better understanding of chlorine characteristics in large-scale WTE plants thereby assisting in reducing chlorine corrosion.

Mechanism of fluidized chlorination reaction of Kenya natural rutile ore

In this paper, the thermodynamics and kinetics of nature rutile carbochlorination in a fluidized-bed were investigated. The thermodynamic calculations of TiO2–C–Cl2 system show that when C is excess in the solid phase, titanium tetrachloride and carbon monoxide can exist stably. At high temperature, the reaction with CO as the product is the dominant reaction. The appropriate reaction conditions are as follows: reaction temperature of 950 °C, reaction time of 40 min, carbon ratio of 30 wt% of rutile, natural rutile particle size of −96 μm, petroleum coke size of −150 μm, and chlorine flow of 0.036 m3·h−1. Under the above conditions, the reaction conversion rate of TiO2 can reach about 95 %. This paper proposed a reaction rate model, and got a rutile chlorination rate formula, which is generally consistent with the experimental data. For the TiO2–C–Cl2 system, the reaction rate is dependent on the initial radius of rutile particle, density, and the partial pressures of Cl2. From 900 to 1,000 °C, the apparent activation energy is 10.569 kJ·mol−1, and the mass diffusion is found to be the main reaction-controlling step. The expression for the chlorine reaction rate in the C–Cl2 system is obtained, and it depends on the degree of reaction, the partial pressure of Cl2, and the size of rutile particle.

Chloride Deposit Formation in a 24 MW Waste to Energy Plant

Waste-to-energy (WTE) plants are utilized for the production of heat and electricity from municipal solid waste (MSW) and refused derived fuel (RDF). However, a desire to raise the steam temperature in order to improve the electrical efficiency of WTE plants has introduced potential high temperature corrosion problems to the heat transfer surface, due to high chlorine content (0.5wt.%∼1.0wt.%) in MSW. To study the corrosion mechanism and deposits chemistry, full scale investigations were therefore conducted in a WTE plant in Tianjin, China. Deposit and corrosion probes were inserted and exposed to the flue gas at five different locations. After nine months exposure, two different alloy probes were taken out and analyzed. Meanwhile, the chlorine flow in the waste incinerator was also investigated via stack sampling and analysis of the residue's composition. The results showed: the most significant outlet for chlorine flow is via fly ash, accounting for 40.3% of total chlorine. Other main distributions are approximate 6.7% in bottom ash, 31.4% in semi-dry scrubber and bag filter ash, 2.75% discharged from stacks and rest in the leachate. The chlorine content was 0.92% via back-calculation method, which kept consistence with the elemental analysis. The deposits on the probes showed similar but distinct characteristics: all deposits were rich in sulfur and calcium content, potassium decreasing with flue gas flow suddenly showed highest value at Evaporator. With the deposits growth, the deposits can be classified into outer, inner and interface. The sodium and sulfur contents were rich in interface; silicon and magnesium were rich in inner; and calcium and chlorine were very high in the outer.

Use of On-line Water Quality Monitoring Data to Predict Bacteriological Failures

Variations in continuously monitored on-line water quality data were investigated to establish whether they could be linked to coliform detections at regulatory monitoring points. We focussed on chlorine residual, turbidity and flow rate at water treatment works (WTW)-A. Archived on-line monitoring data from WTW-A were analysed using cross-correlation and self-organising maps in MATLAB® to identify trends in the data running up to coliform detections. The results show that these tools could be developed to help manage WTWs to reduce the number of bacteriological failures. A fingerprint of WTW conditions relating to coliform failures was identified for this case study.