Inorganic elements in palm empty fruit bunch (EFB) are problematic in boiler operation, causing slagging and fouling deposits. The first pilot-scale hydrothermal treatment (HTT) system was commenced in a palm oil mill to remove undesirable elements. Fuel properties, combustion behavior, and fouling deposition of HTT-EFB were investigated. Liquid temperatures and treatment times in the HTT system significantly altered EFB-fuel properties. At ≥ 60 °C, potassium removals of at least 78 % were achieved, generating EFB-fuel containing potassium below 0.5 %wt. Later, a series of EFB combustion experiments were conducted in a specially designed fixed-bed reactor to simulate the tube surface of industrial boilers. Fouling deposition from HTT-EFB combustion reduced to below half of untreated EFB at all HTT conditions and combustion temperatures studied. The deposit-to-fuel ratio of HTT-EFB combusted at 1,000 °C was 37.3 % lower than untreated EFB combusted at a typical EFB boiler at 800 °C. Results demonstrated great potential for HTT-EFB in industrial applications.

Circulating Fluidized Bed (CFB) boiler often experience leaks in the wall tube due to corrosion and abrasion of the bed material after use that varies between 3 and 8 months. To avoid erosion corrosion, a coating was done in the form of Chrome Clad Tube Armor (CTA). In this research, a Failure Analysis (FA) was performed on the characterization of the boiler tube using several types of samples, which are Wall Tube Without Coating (WT) and CTA (in new condition and after eight months of use). Macro visual, Field emission scanning electron microscopes (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), corrosion, and Thermogravimetric analysis (TGA) tests showed that the CTA type has better corrosion and thermal resistance. The hardness values of the CTA and WT coating substrates after eight months of use were 197.75 and 195.2 HV. The failure mechanism on the tube was caused by high temperatures (long-term overheating) and friction between the tube and the fluid or metal. Wall tubes in furnaces fail due to erosion and corrosion due to fluid and solid particle mixtures and environmental contact.

In this paper, we propose a data classification and analysis method to estimate fire risk using facility data of thermal power plants. To estimate fire risk based on facility data, we divided facilities into three states-Steady, Transient, and Anomaly-categorized by their purposes and operational conditions. This method is designed to satisfy three requirements of fire protection systems for thermal power plants. For example, areas with fire risk must be identified, and fire risks should be classified and integrated into existing systems. We classified thermal power plants into turbine, boiler, and indoor coal shed zones. Each zone was subdivided into small pieces of equipment. The turbine, generator, oil-related equipment, hydrogen (H2), and boiler feed pump (BFP) were selected for the turbine zone, while the pulverizer and ignition oil were chosen for the boiler zone. We selected fire-related tags from Supervisory Control and Data Acquisition (SCADA) data and acquired sample data during a specific period for two thermal power plants based on inspection of fire and explosion scenarios in thermal power plants over many years. We focused on crucial fire cases such as pool fires, 3D fires, and jet fires and organized three fire hazard levels for each zone. Experimental analysis was conducted with these data set by the proposed method for 500 MW and 100 MW thermal power plants. The data classification and analysis methods presented in this paper can provide indirect experience for data analysts who do not have domain knowledge about power plant fires and can also offer good inspiration for data analysts who need to understand power plant facilities.

The generation of water vapor is crucial for the petrochemical industry. In order to protect the boiler from damage, the re-injected water must not contain any suspended matter, especially hydrocarbons. Moreover, it is condensed steam with a temperature close to 100 °C and the unintentional creation or chronic generation of pollution, respectively, that can more or less produce the concentrated pollution. In this context, membrane processes appear promising in order to achieve this reuse and more especially crossflow ceramic membranes. The novelty of this paper is to study the retention of hydrocarbons and suspended solids contained in the condensate hot water of a high-capacity boiler using ceramic ultrafiltration membranes. In total, two ultrafiltration molecular weight cut-offs were used: 50-150 kDa. Several operating parameters were studied such as effluent type (accidental or chronic pollution), temperature, transmembrane pressure, initial volume, and pilot plant size. In all cases, retention of suspended matter was above 90% and residual hydrocarbon concentrations were under 0.1 ppm even for high-volume concentrations. Control of the transmembrane pressure and the molecular weight cut-off of the membrane are key to optimizing the process. Despite the high-volume concentration obtained, the membranes were perfectly regenerated with conventional cleaning procedures.

Waste heat dissipated in the exhaust system of a combustion engine represents a major source of energy to be recovered and converted into useful work. The Waste Heat Recovery System (WHRS) based in an Organic Rankine Cycle (ORC) is an approach for recovering energy from heat sources, achieving a significant reduction in fuel consumption and, as a result, exhaust emissions. This paper studies pressure drop in an ORC shell-and-tubes boiler for a WHRS implementation experimentally and with computational simulations based on a 1-dimensional heat transfer model coupled with 3D calculations. An experimental database is developed, using ethanol in a pressure range of 10-15 absolute bar as working fluid, with mass fluxes inside the tubes in the range of 349.31 kg/s-m2 and 523.97 kg/s-m2, and inlet temperatures in the range of 60 °C and 80 °C. Thus, the friction factor of different regions of the boiler were estimated using both CFD simulations, experimental data, and bibliographic correlations. Simulations of operating points and the results of the experimental test bench showed good agreement in pressure drop results, with a mean absolute error of 15.47%, without a significant increment in the computational cost.

A comparative study was carried out of emissions from the catalytic combustion of pellets made from furniture board waste and pellets made from wood mixed with Fe2O3. The mass content of the Fe2O3 catalyst in the fuel was varied from 0% to 5%, 10%, and 15% in relation to the total dry mass weight of the pellets. The average flame temperature in the boiler was between 730 and 800 °C. The effect of the catalyst concentration in the fuel was analysed with respect to the contents of O2, CO2, CO, H2, and NOx in the flue gas and the combustion quality of the pellets in the heating boiler. Changes in the CO2 content and the proportion of unburned combustible components in the combustion residue were assessed. It was established that an increase in the Fe2O3 content of the prepared fuels had a positive effect on reducing NOx, CO, and H2 emissions. However, the proportion of iron oxide in the tested fuel pellets did not significantly influence changes in their combustion quality. A strong effect of the addition of Fe2O3 on the reduction of the average NOx content in the flue gas occurred with the combustion of furniture board fuel, from 51.4 ppm at 0% Fe2O3 to 7.7 ppm for an additive content of 15%. Based on the analysis of the residue in the boiler ash pan, the amount of unburned combustibles relative to their input amounts was found to be 0.09-0.22% for wood pellets and 0.50-0.31% for furniture board waste pellets.

When stay-at-home orders were issued to slow the spread of COVID-19, building occupancy (and water demand) was drastically decreased in many buildings. There was concern that widespread low water demand may cause unprecedented Legionella occurrence and Legionnaires’ disease incidence. In lieu of evidenced-based guidance, many people flushed their water systems as a preventative measure, using highly variable practices. Here, we present field-scale research from a building before, during, and after periods of low occupancy, and controlled stagnation experiments. We document no change, a > 4-log increase, and a > 1.5-log decrease of L. pneumophila during 3- to 7-week periods of low water demand. L. pneumophila increased by > 1-log after precautionary flushing prior to reoccupancy, which was repeated in controlled boiler flushing experiments. These results demonstrate that the impact of low water demand (colloquially called stagnation) is not as straight forward as is generally assumed, and that some flushing practices have potential unintended consequences. In particular, stagnation must be considered in context with other Legionella growth factors like temperature and flow profiles. Boiler flushing practices that dramatically increase the flow rate and rapidly deplete boiler temperature may mobilize Legionella present in biofilms and sediment.

Combustion stands as one of the essential methods in resource recovery for disposal of distillery sludge. In this study, sludge along with coal has been considered an option for co-combustion in the grate furnace aiming for further application as a boiler fuel. Detailed analysis was carried out to verify the feasibility of co-combustion of sludge with coal. Distillery sludge was blended with coal as a mixed fuel at co-combustion ratios of 20%, 30%, and 40% in grate furnace. The results of the analysis indicated that the combustion with 40% sludge mixed coal is suitable for application as a fuel in boiler. According to the chemical composition of bottom ash, weight loss from 460 to 800°C indicated the presence of C-C and C-H. Also, EDX and XRD analyses of mixed fuel was carried out to determine the mineralogical composition. The presence of quartz (SiO2), mullite (3Al2O32SiO2), and hematite (Fe2O3) present in the ash can be used as mineral additives in cement industries. The study also provided a promising approach towards diverting combustion bottom ash from landfills for its utilization in various industries which can be a possible cost-effective solution.

Gas boilers dominate domestic heating in the UK, and significant efficiency improvements have been associated with condensing boilers. However, the potential remains for further efficiency improvement by refining the control, system specification and installation in real dwellings. Dynamic building simulation modelling, including detailed heating system componentry, enables a deeper analysis of boiler underperformance. This paper explores the link between the space heat oversizing of boilers and on/off cycling using dynamic simulation, and their subsequent effect on boiler efficiency and internal temperatures. At plant size ratio (PSR) 8.5 daily cycles numbered over 50, similar to median levels seen in real homes. Simulations show that typical oversizing (PSR >3) significantly increases cycling behaviour and brings an efficiency penalty of 6-9%. There is a clear link between raising PSR, increased cycling and an associated decreased efficiency; however, in the UK, boilers are regularly oversized with respect to space heating, especially combination boilers to cover peak hot water demand. Current legislation and labelling (ErP and SAP) overlook PSR as a determinant of system efficiency, failing to incentivise appropriate sizing. Reducing boiler oversizing through addressing installation practices and certification has the potential to significantly improve efficiency at low cost, decreasing associated carbon emissions. Practical application: This research provides the basis for a practical and cost effective means of assessing the potential for underperformance of boiler heating systems at the point of installation or refurbishment. By assessing the oversizing of the boiler with respect to space heating, unnecessary cycling and the associated efficiency penalty can be avoided. Plant size ratio, as an indicator of cycling potential, can be implemented in energy performance certificates (EPCs), through the standard assessment procedure (SAP), using existing data. The potential for real carbon savings in the existing boiler stock is considerable, and the findings have wider implications for next generation heating systems.

Readily available temperature sensing in boilers is necessary to improve efficiencies, minimize downtime, and reduce toxic emissions for a power plant. The current techniques are typically deployed as a single-point measurement and are primarily used for detection and prevention of catastrophic events due to the harsh environment. In this work, a multi-point temperature sensor based on wavelength-multiplexed sapphire fiber Bragg gratings (SFBGs) were fabricated via the point-by-point method with a femtosecond laser. The sensor was packaged and calibrated in the lab, including thermally equilibrating at 1200 °C, followed by a 110-h, 1000 °C stability test. After laboratory testing, the sensor system was deployed in both a commercial coal-fired and a gas-fired boiler for 42 days and 48 days, respectively. The performance of the sensor was consistent during the entire test duration, over the course of which it measured temperatures up to 950 °C (with some excursions over 1000 °C), showing the survivability of the sensor in a field environment. The sensor has a demonstrated measurement range from room temperature to 1200 °C, but the maximum temperature limit is expected to be up to 1900 °C, based on previous work with other sapphire based temperature sensors.