Water Blast Research Articles

Chemical Cleaning of Crude Oil Fouling Deposits; Applying the Coke Spectrum

Fouling of heat exchangers and refining equipment by crude oil deposits is a chronic operating problem. In general, many such deposits are narrowly defined as coke fouling, for which the prescribed cleaning has traditionally been high-pressure water blasting. The results for this type of cleaning are mixed at best. Heat exchangers are often returned to service at conditions less than 85% clean performance, driving the need for more efficient cleaning regimens. A detailed characterization of 62 field-based crude oil fouling deposits from hydrocarbon process units was presented by the authors in 2019. This paper demonstrated that such deposits are exceptionally complex, resulting in the introduction of the Coke Spectrum. Here, these deposits are revisited, and chemical cleaning methods are applied. Chemical cleaning encompasses a variety of applications. Circulation, ultrasonic immersion, and clean-in-place techniques were reviewed on laboratory-scale samples to determine what chemical cleaning agents are most effective toward the various categories of foulant making up the Coke Spectrum. Combination techniques which employ both chemical and mechanical applications simultaneously or in sequence are considered in depth. The correlation between chemical composition and the effectiveness of the cleaning method is explored with considerations for scaling from laboratory to industrial application.

Modeling and analysis of domino effect in petrochemical storage tank farms under the synergistic effect of explosion and fire

The synergistic effect of explosion and fire (SEEF) is one of the challenges of domino effect risk assessment for petrochemical storage tank farms. However, the domino effect probabilities at different orders and accident propagation patterns in storage tank farms under the SEEF are still unclear. An approach based on Bayesian networks is developed to model the propagation of domino effects in storage tank farms under the SEEF. The method accounts for the temporal and spatial synergistic effects of blast wave and fire thermal radiation in multiple accidents during domino accident escalation and the damage enhancement effect caused by the SEEF on the target units. Application of the method to a real tank farm highlights that the SEEF has a significant impact on the domino effect probabilities. Compared with only considering a single accident type, the SEEF leads to an increase in the domino effect probabilities of the tank farm. Installing water deluge systems and blast walls for all tanks at the same time is an effective safety measure to mitigate domino effects due to the SEEF. When safety resources are limited, the priority to equip critical tanks with water deluge systems and blast walls can also mitigate the domino effects.

Investigating the effects of nano-blast furnace slag powder on the behaviour of composite cement materials

Attributable to the depletion of raw materials and for sustainability purposes in construction works. Therefore, this study looked into the effects of nano blast furnace slag (BFS) on the microstructure, mechanical properties, and durability of mortar. BFS was substituted for cement at various weight percentages of 0, 1, 1.5, 3, 5, and 7%.A suspension of water and Nano blast furnace slag was made using ultrasonic mixers to prepare the samples. The suspension was combined with cement and sand using 1 cement, 0.5 water, and 2.75 sand in the mixture to make cement mortar. The mixture was then shaped, left in the mould for 24 hours, and then allowed to cure for 7, 14, 28, 60, and 91 days. SEM was used to investigate the microstructure before and after cement replacement. The mechanical characteristics were evaluated by testing the compressive strength and the surface hardness. While the durability was assessed using the water absorption ratios.The results revealed that increasing the BFS in the mortar improved mechanical characteristics and durability by up to 3% of BFS. Replacing Nano-blast furnace slag for a portion of the cement is a proposed solution to address the problems of environmental pollution and resource consumption caused by cement production.Another sustainable material needs to be used for additional investigation. We may evaluate more properties and use different weight percentages.Each year, a significant amount of slag is produced as a result of the iron industry, endangering the environment. There have been numerous initiatives to reduce slags negative environmental consequences. Using slag to replace some of the cement is one of the options to eliminate this byproduct and reduce excessive cement use.This study investigates the possibility of using a blast furnace blast within the Nanoscale to replace some of the cement used in the construction due to the positive impact on the environment to get rid of industrial byproducts and decrease the use of cement.

Highly robust and hydrophobic aerogel beads with dandelion-like structure for water treatment

Nowadays the human living environment faces grave challenges raised by a series of environmental issues, including water pollution and the greenhouse effect. These crises call for the development of novel materials with functional properties for effective environmental engineering control and robust mechanics to manage various complex conditions. Herein, taking inspiration from dandelion blowballs, we propose a fabrication strategy to prepare hierarchically structured chitosan aerogel beads by combining droplet freeze casting and silylation grafting. The chitosan aerogel beads consist of a hierarchical structure, with a spherical macro-shape, a centrosymmetric radially aligned microstructure, and a nano-scale siloxane coating. As a result, the dandelion-like hierarchical structure endows the aerogel beads with a fine combination of high mechanical efficiency and functional properties. With an average density of only 0.08 g/cm3, the aerogel beads can sustain more than 2.2 MPa of stress at 80% deformation. Their chitosan skeleton, despite being inherently water dissolvable, is modified to be highly hydrophobic (contact angle = 147°, rolling angle = 4.2°), even under prolonged water blasts. Further, the aerogel beads not only showcase the capability to quickly absorb various pollutants with good reusability, but also can be assembled into customizable configurations, demonstrating their filtration capability and excellent thermal insulation with a thermal conductivity of 32.5 mW·m−1·K−1. Benefiting from these excellent properties, our aerogel beads represent a promising engineering material for water treatment and thermal insulation. Also, this work demonstrates a novel approach that couples both material and structural designs for architectured aerogels with excellent mechanical and functional properties.

Toxicity of Antifouling Biocides and Wastes from Ships’ Surfaces during High-Pressure Water-Blasting Cleaning Activities in the Nauplii and Eggs of the Estuarine Copepod Paracalanus parvus sl

Copepods, the dominant member of zooplankton and major grazers of phytoplankton in the pelagic ecosystem, are at risk from exposure to antifouling biocides. To evaluate the developmental toxicity of antifouling biocides (Diuron, Irgarol 1051, Sea-nine 211) and wastewater (from high-pressure water blasting (WHPB) and its MeOH extract (WHPB-MeOH)) in the copepod Paracalanus parvus sl, we investigated the chemical concentration, egg-hatching rate, and nauplius mortality. WHPB samples were obtained through hull-cleaning activities involving WHPB in a dry dock. Among the biocides, Sea-nine 211 had the strongest effects on hatching rates and nauplius mortality, which was followed by Diuron and Irgarol 1051. In the WHPB and WHPB-MeOH samples, there was no significant difference between the experimental groups in terms of the egg-hatching rate; however, WHPB was found to be more toxic in terms of nauplius mortality, suggesting that metals in WHPB may also adversely affect nauplius survival in P. parvus sl. A comparison of the LC50 results of Sea-nine 211 and WHPB revealed that WHPB had a negative effect on nauplius mortality even at a 100-fold lower concentration. Therefore, if chemical contaminants generated during in-water cleaning activity are discharged continuously into the ports without being properly collected through a post-treatment system, they are expected to negatively impact the population of copepods near the port. Although verification is needed through additional experiments, our results could be used for a baseline study concerning the toxicity of antifouling biocides on marine copepod species.

An Alternative Tool for Intra-Row Weed Control in a High-Density Olive Orchard

In high-density olive orchards, weed control along the row is pivotal to avoid the competition between the young trees and the weeds to promote a strong vegetative growth of the olives during the first years after planting. Two different mechanical weeders were compared in a high-density olive orchard (1250 trees ha−1) planted in 2019. An intra-row hoeing machine (Control) and an alternative system with a high-pressure water blast (Grass Killer) were compared. The treatments were carried out in summer and autumn. The effects of the two control systems were assessed through the weed soil coverage and indirectly through the growth of olive trees. The effect on weeds in summer was marked without showing significant differences between the applied treatments, even if the Grass Killer did not eradicate totally the weeds. In autumn, the hoeing machine showed a higher weeding capacity, even though the presence of weeds along the row treated with the high-pressure water weeder can contribute to reduce the soil moisture in wintertime. No differences were seen for the young olive tree growth. Results showed a good weeding capacity of the alternative machine, and its use can be managed in combination with other mechanical systems.

An Experimental Model for the Study of Underwater Pressure Waves on the Central Nervous System in Rodents: A Feasibility Study

Underwater blast differs from blast in air. The increased density and viscosity of water relative to air cause injuries to occur almost exclusively as primary blast, and may cause disorientation in a diver, which may lead to inability to protect the airway and cause drowning. However, cognitive impairments from under water blast wave exposure have not been properly investigated, and no experimental model has been described. We established an experimental model (water shock tube) for simulating the effects of underwater blast pressure waves in rodents, and to investigate neurology in relation to organ injury. The model produced standardized pressure waves (duration of the primary peak 3.5 ms, duration of the entire complex waveform including all subsequent reflections 325 ms, mean impulse 141–281 kPa-ms, mean peak pressure 91–194 kPa). 31 rats were randomized to control (n = 6), exposure 90 kPa (n = 8), 152 kPa (n = 8), and 194 kPa (n = 9). There was a linear trend between the drop height of the water shock tube and electroencephalography (EEG) changes (p = 0.014), while no differences in oxygen saturation, heart rate, S100b or macroscopic bleedings were detected. Microscopic bleedings were detected in lung, intestines, and meninges. Underwater pressure waves caused changes in EEG, at pressures when mild hemorrhage occurred in organs, suggesting an impact on brain functions. The consistent injury profile enabled for the addition of future experimental interventions.

Explosives Use in Decommissioning—Guide for Assessment of Risk (EDGAR): II Determination of Sound Exposure Levels for Open Water Blasts and Severance of Conductors and Piles from below the Seabed

A simple underwater noise model suitable for use with explosive severance of well conductors and piles during the decommissioning of oil and gas subsea structures is introduced and evaluated against data from five projects in the US. This study focuses on a novel model for the determination of sound exposure levels. The model has been developed to enable determination of impact areas for marine mammals and fish. Simulated received underwater sound exposure levels were significantly correlated with measurements for all scenarios. The maximum total error achieved between simulations and measurements was 2.6%, suggesting that predictions are accurate to within 3% of the average measurement. A low relative bias was observed in the simulations when compared to measured values, suggesting only a small systematic underestimate (≤0.5% of average measurement) for most severance operations and a small overestimate (0.14%) for open water blasts.

Explosives Use in Decommissioning—Guide for Assessment of Risk (EDGAR): I Determination of Sound Pressure Levels for Open Water Blasts and Severance of Conductors and Piles from Below the Seabed

A simple underwater noise model suitable for use with explosives in the decommissioning of oil and gas subsea structures is introduced and evaluated against data from five projects in the US. The performance of the model is compared to four existing models for open water blasts, and for the severance of well conductors and piles. Simulated received underwater sound pressure levels were significantly correlated with measurements for all scenarios. The maximum total error achieved between simulations and measurements was 3.5%, suggesting that predictions are accurate to within 4% of the average measurement. A low relative bias was observed in the simulations when compared to measured values, suggesting only a small systematic underestimate (≤1% of average measurement) for most severance operations and a small overestimate (1.34%) for open water blasts.

Predictive modeling for sustainable high-performance concrete from industrial wastes: A comparison and optimization of models using ensemble learners

The cementitious matrix of high-performance concrete (HPC) is highly complex, and ambiguity exists with its mix design . Compressive strength can vary with the composition and proportion of constituent material used. To predict the strength of such a complex matrix the use of robust and efficient machine learning approaches has become indispensable. This study uses machine intelligence algorithms with individual learners and ensemble learners (bagging, boosting) to predict the strength of (HPC) prepared with waste materials. This is done by employing Anaconda (Python). Ensemble learner bagging, adaptive boosting algorithm, and random forest as modified bagging algorithm are employed to construct strong ensemble learner by incorporating weak learner. The ensemble learners are used on individual learners or weak learners including support vector machine and decision tree through regression and multilayer perceptron neural network. The data consists of 1030 data samples in which eight parameters namely cement, water, sand, gravels, superplasticizer , concrete age, fly ash and granulated blast furnace slag were chosen to predict the output. Twenty bagging and boosting sub-models are trained on data and optimization was done to give maximum R 2 . The test data is also validated by means of K-Fold cross-validation using R 2 , MAE, and RMSE. Moreover, evaluation of ensemble models with individual one is also checked by statistical model performance index (e.g., MAE, MSE, RMSE, and RMLSE). The result suggested that the individual model response is enhanced by using the bagging and boosting learners. Overall, random forest and decision tree with bagging give the robust performance of the models with R 2 = 0.92 with the least errors. On average, the ensemble model in machine learning would enhance the performance of the model.

Study on the cavitation effects induced by the interaction between underwater blast and various boundaries

The load of cavitation collapse is one of the main input loads to the structure subjected to underwater explosion. The cavitation effects near different boundaries are of particular importance in understanding the load mechanisms and designing the protective structures. In present study, a numerical model that couples a Runge Kutta Discontinuous Galerkin method, a finite element method and an isentropic one-fluid cavitation model is developed to study the cavitation effects induced by underwater explosion near different boundaries. The boundaries of a rigid plate, a steel plate, a rubber coated plate and a foam coated plate are investigated in detail, after validating the coupled numerical model by a case of 1D cavitating flow in an open tube, an experiment of a water-backed plate subjected to water blast and an experiment of underwater explosion near a circular plate. The evolutions of the cavitation region, the pressure profile near the structure and the responses of the structure are comprehensively discussed. The results are beneficial for guiding the design of the protective structures.

Is hull cleaning wastewater a potential source of developmental toxicity on coastal non-target organisms?

Chemical contaminants can be discharged by vessel hull cleaning processes, such as scraping, jet spraying, and painting, all of which produce readily transportable contaminants into the marine environment, where they are referred to as ‘hotspots’ of contamination in coastal areas. However, many countries have not yet established effective evaluation methods for disposal of waste mixtures or management guidelines for areas of hull cleaning. To define the toxic effects of wastewater from vessel hull cleaning in dry docks on resident non-target organisms, we investigated the chemical concentrations and developmental toxicity on embryonic flounder, which is an organism sensitive to chemical contamination. In this study, the dominant inorganic metal discharged was zinc when cleaning Ship A (300 tons) and copper for Ship B (5,000 tons). The wastewater from high-pressure water blasting (WHPB) of Ship A (300 tons) and Ship B (5,000 tons) produced a largely overlapping suite of developmental malformations including pericardial edema, spinal curvature, and tail fin defects. Forty-eight hours after exposure, the frequency percentage of malformation began to increase in embryos exposed to a 500-fold dilution of WHPB from Ships A and B. We performed transcriptome sequencing to characterize the toxicological developmental effects of WHPB exposure at the molecular level. The results of the analysis revealed significantly altered expression of genes associated with muscle cell differentiation, actin-mediated cell contraction, and nervous system development (cutoff P < 0.01) in embryonic flounder exposed to high-pressure cleaning effluent from Ship A. Genes associated with chromatin remodeling, cell cycling, and insulin receptor signaling pathways were significantly altered in embryonic flounder exposed to WHPB of Ship B (cutoff P < 0.01). These findings provide a greater understanding of the developmental toxicity and potential effects of WHPB effluent on coastal embryonic fish. Furthermore, our results could inform WHPB effluent management practices to reduce impacts on non-target coastal organisms.

Study on effect of strength and durability parameters and performance of Self Compacting Concrete replacement with GGBS at different dosages

To investigate experimentally, the behavior of exterior beam-column joint and strength characteristics of Self Compacting Concrete (SCC) containing Viscosity Modifying Admixture (VMA), and Ground Granulated Blast Furnace Slag (GGBFS). Since there is no standard method of mix design is available for SCC. Hence mix design was arrived as per the rules of European Federation of National Associations Representing for Concrete (EFNARC). Marsh cone test was used to find the saturation of various kind of cements by adding the dosage of super plasticizer accordingly. In this investigation SCC was made by usual ingredients such as cement, fine aggregate, coarse aggregate, water and ground granulated blast furnace slag at various replacement levels (10%, 20%, 30%, 40%, and 50%), with that the Super Plasticizer (Glenium B233) and viscosity modifying agent (Glenium Stream 2) was used in appropriate amount for achieving the better flow in the concrete. The experiments were carried out by maintaining a constant water-powder ratio of 0.45. At various replacement levels the performance of freshly prepared SCC is checked by conducting tests such as slump flow, T50 slump flow, U-tube, L-box and V-funnel tests. Mechanical characteristics like Compressive, Split-tensile and Flexural strength examined. Also, the durability study for SCC after 28, 56 and 90 days curing was done by conducting a number of the tests like saturated water absorption, porosity, carbonation depth and alkalinity measurement

Numerical Investigation on Water Blast Response of Freestanding Carbon Fiber Reinforced Composite Sandwich Plates with Square Honeycomb Cores

The dynamic response of freestanding carbon fiber reinforced composite sandwich plates with square honeycomb cores of different relative densities subjected to water blast is investigated by numerical simulations. The constitutive models are validated by quasi-static compression response comparisons of numerical simulations and theoretical calculations. The deformation process, core compression and momentum transmitting characteristics are analyzed and the regulations of the core compression and momentum transmitting for sandwich plates with different core relative densities are revealed. Dynamic response and protection property of composite sandwich plates and mass-equal laminate plates are compared, which indicates that the composite sandwich plates can provide superior protection from water blast than laminate plates.

Research status and future trends on surface pre-grouting technology in reforming wall rock of vertical shafts in coal mines in China

In the mine construction, the surface pre-grouting technology is an important method to prevent water blast in excavation process of vertical shaft when the shaft must pass through the thick, water-rich and high water-pressure bedrock aquifer. It has been nearly 60 years since the technology was used to reform wall rock of vertical shaft in coal mine in China for the first time, and the existing technology can basically meet the needs of constructing 1000m deep vertical shaft. Firstly, the article introduces that in view of Magg’s spherical seepage theory and Karol’s spherical seepage theory, Chinese scholars found that the diffusion of grout from borehole into the surrounding strata in horizontal direction is irregular through a lot of research and engineering practice of using the surface pre-grouting technology to reform wall rock of vertical shafts, and put forward the selecting principles of grout’s effective diffusion radius in one grouting engineering; Secondly, according to the shape of the grouting boreholes, surface pre-grouting technology of vertical shaft is divided into two stages: vertical borehole stage and S-type borehole stage. Thirdly, the development status of grouting materials and grouting equipment for the technology is introduced. Fourthly, grouting mode, stage height and pressure of the technology are introduced. Finally, it points out that with the increasing depth of coal mining in China, the technology of reforming wall rock of 1000~2000m deep vertical shafts will face many problems, such as grouting theory, grouting equipment, grouting finishing standard, testing and evaluation of grouting effect, and so on. And it put forward a preliminary approach to solving these problems. This paper points out future research directions of the surface pre-grouting technology in China.

Marine composite sandwich plates under air and water blasts

Fluid-structure interaction solutions for the air and water blast response of marine composite sandwich panels with crushable foam cores are presented in this paper. Reflected and radiated acoustic pressure waves were introduced using Taylor's FSI method into Lagrange's equations of motion for the sandwich plate. In comparison to air blast, water-structure interactions diminished deflection and slowed down the response of the sandwich panel for a given pressure pulse loading. The predicted elastic-plastic transient response of the sandwich panel from the analytical model was shown to be fairly consistent results with ABAQUS Explicit. Pressure amplitudes to initiate damage in a sandwich panel with E-glass/Vinyl Ester facesheets and PVC H250 foam core were calculated under water blast/air back, water blast/water back, and air blast/air back conditions. It took significantly higher pressures to initiate damage in the panels under water blast/air back and water blast/water back conditions than in the air blast/air back plate because of fluid damping and higher plastic work dissipation in the core. A parametric study showed that on a per unit areal weight basis, panels with softer, more ductile foams were more blast resistant than panels with strong and stiff cores because of work dissipation during core plasticity. In the water blast cases, foam yielding was affected by transverse compression and not only transverse shear, as is usually case in air blast-loaded sandwich panels.

Underwater blast resistance of sacrificial claddings with small/significant strain hardening

The vitality and fighting capacity of warships will be influenced by the underwater explosion–induced shock loadings. The foam materials have excellent energy dissipation capabilities and are widely used in mitigating impact/shock. In this article, a one-dimensional model for the shock mitigation of cellular claddings exhibiting small/significant strain hardening is proposed for both water blast loading and hydrostatic pressure. Special emphases are concentrated on the cellular material compression with actual stress–strain relationship and the effects of hydrostatic pressure on the shock mitigation performance of the cladding. Finite element models are developed to verify the analytical model. When considering the actual material relationship of the cellular claddings, the compaction mechanism is complex due to multiple reflections. A reflected secondary compression wave generates and propagates from the clamped end to the impinged end for a foam block with finite thickness. Later, there are even third or more compaction waves. It is worth to note that the part inside the secondary compacted zone continue to deform in quasi-static “Homogeneous” mode. Moreover, the effects of the hydrostatic pressure on the foam compression are revealed. The results can guide the design of such cellular claddings to water blast for naval ships.

Predict effective thickness of sacrificial cellular claddings to shallow/deep water blast

The cellular materials are well known to mitigate shock loadings. However, they may attenuate or enhance the shock transmitted to the protected structures. This paper is devoted to derive an explicit expression of the effective foam thickness when subjected to deep underwater explosion. Hereinafter, the effective foam thickness represents the crushed foam when the shock energy is just completely absorbed, i.e. the attenuation/enhancement boundary. One-dimensional (1D) analytical model which can consider the core crushing, the fluid-structure interaction (FSI), the cavitation phenomenon and the initially applied static pressure is proposed to solve the problem. The analytical model is then used for the parametric study. Finally, the empirical formulae of the effective foam thickness is derived from the results of the parametric study. In practical applications, the empirical formulae for the effective foam thickness can guide the design of such cellular claddings to water blast.

Novel experimental and 3D multiphysics computational framework for analyzing deformation and failure of composite laminates subjected to water blasts

The load-carrying capacity of composite structures under water-based impulsive loads is studied in relation to different materials and loading conditions. The analysis focuses on the role of fiber orientation, fiber stiffness and angle of structure obliquity relative to load direction on the deformation and failure in monolithic carbon-fiber and glass-fiber/epoxy composite plates of similar mass and thickness. Structures are subjected to impulsive loads of different intensities generated using the Underwater Shock Loading Simulator (USLS), a novel projectile-impact-based impulsive loading facility. In-situ high-speed digital imaging is used to study the deformation and failure, focusing on the effects of load intensity, failure modes and material heterogeneity. The experiments are combined with fully dynamic 3D Coupled Eulerian Lagrangian (CEL) finite element simulations accounting for the effects of fluid-structure interactions (FSI) and in-ply and inter-ply cracking and failure. It is found that the carbon-fiber laminates provide higher blast resistance, but transmit a greater fraction of the incident impulse to the supports than the glass-fiber laminates. Damage through in-ply and inter-ply cracking in the carbon-fiber laminates is ∼25% of that in the glass-fiber laminates. Higher angles of load obliquity trigger localized deformation at multiple locations, leading to more extensive in-ply damage and progressively shear-dominated rupture.

Time Domain Spectral Element method to Study Response of a Sandwich Beam with Compliant Core Subjected to Under Water Explosion

A spectral element formulation is developed for a sandwich beam with stiff face sheets and a compliant core. Higher order displacement functions are taken for the core in order to incorporate the core compression effects. Highly efficient spectral element method is used for the study. Accuracy and the computational efficiency of this method are compared with the conventional finite element method in solving transient blast loading case. Using this spectral element method, under water blast loading response of a sandwich beam with composite face sheets and core is studied. A comparison is made between the response of stiff core and compliant core sandwich beam models. The study presents a design approach for an optimal configuration for under water blast resistant structures.