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Article
Publication date: 22 October 2019

Kanwar Pal Singh, Arvind Kumar and Deo Raj Kaushal

This paper aims to the transportation of high concentration slurry through pipelines that will require thorough understanding of physical and rheological properties of slurry, as…

Abstract

Purpose

This paper aims to the transportation of high concentration slurry through pipelines that will require thorough understanding of physical and rheological properties of slurry, as well as its hydraulic flow behavior. In spite of several contributions by the previous researchers, there is still a need to enrich the current understanding of hydraulic conveying through pipeline at various flow parameters. The pilot plant loop tests, particularly at high concentrations, are tedious, time-consuming and complex in nature. Therefore, in the current research the prediction methodology for slurry pipeline design based on rheological model of the slurry is used for calculation of pressure drop and other design parameters.

Design/methodology/approach

It has been established that slurry rheology plays important role in the prediction of pressure drop for laminar and turbulent flow of commercial slurries through pipeline. In the current research fly ash slurry at high concentration is chosen for rheological analysis. The effect of particle size and solid concentration is experimentally tested over the rheological behavior of slurry and based on the rheological data a correlation is developed for calculation of pressure drop in slurry pipeline.

Findings

The present study strongly supports the analytical approach of pressure drop prediction based on the rheological parameters obtained from the bench scale tests. The rheological properties are strongly influenced by particle size distribution (PSD), shear rate and solid mass concentration of the slurry samples. Pressure drop along the pipeline is highly influenced by flow velocity and solid concentration. The presence of coarser particles in the slurry samples also leads to high pressure drop along the pipeline. As the concentration of solid increase the shear stress and shear viscosity increase cause higher pressure drop.

Research limitations/implications

The transportation of slurry in the pipeline is very complex as there are lot of factors that affect the flow behavior of slurry in pipelines. From the vast study of literature it is found that flow behavior of slurry changes with the change in parameters such as solids concentration, flow velocity, PSD, chemical additives and so on. Therefore, the accurate prediction of hydraulic parameter is very difficult. Different slurry samples behave differently depending upon their physical and rheological characteristics. So it is required to study each slurry samples individually that is time-consuming and costly.

Practical implications

Nowadays in the world, long distance slurry pipelines are used for the transportation of highly concentration slurries. Many researchers have carried out an experiment in the design aspects of hydraulic transportation system. Rheological characteristics of slurry also play crucial role in determining important parameters of hydraulic conveying such as head loss in commercial slurry pipeline. The current research is useful for the prediction of pressure drop based on rheological behavior of fly ash slurry at various solid concentrations. The current research is helpful for finding the effect of solid concentration and flow velocity on the flow behavior of slurry.

Social implications

Slurry pipeline transportation has advantages over rail and road transportation because of low energy consumption, economical, less maintenance and eco-friendly nature. Presently majority of the thermal power plants in India and other parts of the world dispose of coal ash at low concentration (20 per cent by weight) to ash ponds using the slurry pipeline. Transporting solids in slurry pipelines at higher concentrations will require a thorough knowledge of pressure drop. In the current research a rheological model is proposed for prediction of pressure drop in the slurry pipeline, which is useful for optimization of flow parameters.

Originality/value

All the experimental work is done on fly ash slurry samples collect from the Jharli thermal power plant from Haryana State of India. Bench scale tests are performed in the water resource laboratory of IIT Delhi for physical and rheological analysis of slurry. It has been shown in the results that up to solid concentration of 50 per cent by mass all the samples behave as non-Newtonian and follows a Herschel–Bulkley model with shear thickening behavior. In the present research all the result outcomes are unique and original and does not copied from anywhere.

Details

World Journal of Engineering, vol. 16 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 14 August 2017

Leandro Michalovicz, Warren Albert Dick, Eduardo Cimino Cervi, Cassio Antonio Tormena and Marcelo Marques Lopes Müller

Animal liquid manure contains large amounts of phosphorus (P), which is susceptible to runoff losses when manure is surface-applied on farms as a soil amendment. Even very small…

Abstract

Purpose

Animal liquid manure contains large amounts of phosphorus (P), which is susceptible to runoff losses when manure is surface-applied on farms as a soil amendment. Even very small quantities of P can have a large impact on waterways and lead to eutrophication. Previous studies have shown that flue gas desulfurization (FGD) gypsum, a coal combustion by-product, can reduce P losses from runoff in soils. Therefore, the authors hypothesize that FGD gypsum could reduce nutrients in liquid manure prior to field applications. The purpose of this paper is to evaluate the effect of FGD gypsum to reduce P and suspended solids (SS) concentrations in liquid manure, also determining its proper rate(s) and minimum time of reaction.

Design/methodology/approach

The experimental design was completely randomized with three replicates. Each plot was constituted by a polyvinyl chloride (PVC) column (1 m height and 0.15 m diameter). Dairy liquid manure and FGD gypsum rates (0, 0.62, 1.25 and 2.5 mgl−1) were added to the PVC columns and manually shaken for two minutes. Sampling was performed at 0.35, 0.65 and 0.95 m depths after 0 (immediately after shaking), 4, 8, 16 and 24 hours. Amount of phosphorus was determined by a colorimetric method and solids concentration by mass difference.

Findings

FGD gypsum reduced P concentrations in the liquid manure after four hours of reaction. The most effective rate was 0.62 mgl−1at a 0.35 m depth. FGD gypsum increased SS concentrations in depth in all treatments.

Originality/value

There are growing concerns regarding the fate of nutrients, especially phosphorus, from land application of animal waste. The results indicated that treating liquid manure in the settling tanks with FGD gypsum before field application can be particularly useful on farms where surface-manure is applied, reducing potential losses of P following manure applications, and consequently the eutrophication risk to waterways.

Details

Management of Environmental Quality: An International Journal, vol. 28 no. 5
Type: Research Article
ISSN: 1477-7835

Keywords

Article
Publication date: 11 June 2018

Jason Jie Xiang Bui, Yee Yong Tan, Fu Ee Tang and Carrie Ho

This study aims to investigate the hydraulic behaviour of a pilot-scale, two-staged, vertical flow constructed wetland (VFCW) for septage treatment, in terms of factors such as…

Abstract

Purpose

This study aims to investigate the hydraulic behaviour of a pilot-scale, two-staged, vertical flow constructed wetland (VFCW) for septage treatment, in terms of factors such as hydraulic retention time and hydraulic loading rate and its influence on the treatment dynamics. Because of intermittent feeding mode of VFCW systems and variation in its loading, its hydraulic behaviour is highly variable and need to be understood to optimize its treatment performance.

Design/methodology/approach

Tracer test were carried out using bromide ion with varying hydraulic loading rates (HLR) of 6.82 cm/d, 9.09 cm/d and 11.40 cm/d (i.e. equivalent to 75 L/d, 100L/d and 125 L/d). Tracer data is then analysed using the Residence Time Distribution (RTD) method.

Findings

RTD analysis showed that the increase in HLR increases the average hydraulic retention time (HRT). Subsequently, the increase in HLR results in a lower recovery of effluent, resulting in poor productivity in treatment. The study also showed that the removal of nitrogen and organic matter improved with increasing HRT. However, observations show no correlation between HRT and total solids removal.

Originality/value

A performance evaluation method (by tracer) is proposed to understand the hydraulics of flow in constructed wetlands, which has not been widely studied. Additionally, the dynamics of treatment in VFCWs treating septage may also be revealed by the tracer method. The study can be applied to any constructed wetlands designed for treatment of wastewater, septage or sludge.

Article
Publication date: 25 September 2018

Kaushal Kumar, Satish Kumar, Munish Gupta and Hem Chander Garg

This paper aims at erosion wear experimentation conducted on two piping materials, namely SS202 and SS304 to establish the effect of rotational speed, concentration and time…

Abstract

Purpose

This paper aims at erosion wear experimentation conducted on two piping materials, namely SS202 and SS304 to establish the effect of rotational speed, concentration and time period.

Design/methodology/approach

Erosion wear because of slurry flow is investigated using a slurry erosion pot tester. Fly ash is taken as erodent material having different solid concentrations lie in range 30 to 60per cent (by weight). Experiments are performed at four different speeds, i.e. 600; 900; 1,200; and 1,500 rpm for time duration of 90, 120, 150 and 180 min, respectively. To enhance erosion wear resistance of both piping materials, high-velocity-oxy-fuel coating technique is used to deposit WC-10Co4Cr coating. The parametric influence of erosion wear is optimized using Taguchi method.

Findings

The results show that significant improvement in erosion wear resistance is observed by deposition of WC-10Co4Cr coating. It is observed that rotational speed is found as highly influencing parameter followed by concentration and time duration. Parametric investigation of erosion wear is helpful to develop a procedure for minimizing the erosion wear in pipeline for the flow of solid-liquid mixture.

Originality/value

Slurry erosion wear of WC-10Co4Cr coated stainless steel (SS202 and SS304) is substantiated by extensive microstructural analysis and optimization technique.

Details

Industrial Lubrication and Tribology, vol. 70 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 November 2011

Prodyut Chakraborty and Pradip Dutta

The purpose of this paper is to present a new numerical approach for modeling the multi‐phase flow during an alloy solidification process. In many solidification processes…

Abstract

Purpose

The purpose of this paper is to present a new numerical approach for modeling the multi‐phase flow during an alloy solidification process. In many solidification processes, advection of solid may have a dramatic effect on bulk convection field as well as on the solid front growth and hence on the macro‐segregation pattern. In the present work, a numerical model is developed to simulate directional solidification in presence of melt convection as well as solid advection in the form of sedimentation. A 2D cavity filled with hyper‐eutectic aqueous ammonium chloride solution (25 wt.% of ammonium chloride) being chilled from one of the side walls has been chosen as the model problem for the numerical simulation.

Design/methodology/approach

A fixed grid volume averaging technique has been used for solving mass, momentum, energy, and species equation while taking into account the solid phase advection and local re‐melting. Two different criteria have been identified for the solid particles in the mushy zone to be mobile. These two criteria are represented by a critical solid fraction, and a critical velocity. Based on these two criteria, the mushy zone has been subdivided into two different regions namely, an immobile coherent zone consisting of packed equiaxed crystals and a mobile non‐coherent zone where the solid crystals are able to move.

Findings

The numerical results are compared with corresponding experimental observations.

Originality/value

The solid advection velocity and source terms dealing with solid velocity have been calculated using an explicit scheme, whereas the main conservation equations are solved using an implicit scheme.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 8 May 2018

Mohammed Ahmed Al-Bukhaiti, Ahmed Abouel Kasem Mohamad, Karam Mosa Emara and Shemy M. Ahmed

This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In…

Abstract

Purpose

This paper aims to investigate the influence of slurry concentration on the erosion behavior of AISI 5117 steel and high-chromium white cast iron by using a whirling-arm rig. In this study, the slurry erosion mechanism with particle concentration has been studied.

Design/methodology/approach

The tests were carried out with particle concentrations in the range of 1-7 Wt.%, and the impact velocity of slurry stream was 15 m/s. Silica sand with a nominal size range of 500-710 µm was used as an erodent. The study revealed that the failure mode was independent of concentration.

Findings

The results showed that the erosion rate decreases with the increase in particle concentration and the variation in the reduction depends on the material. It was found that the variation of fractal dimension calculated from slope of linearized power spectral density of eroded surface image for different concentrations can be used to characterize the slurry erosion intensity in a similar manner to the erosion rate. It was also found that the variation of fractal dimension versus concentration of sand has a general trend that does not depend on magnification factor.

Originality/value

Using the gravitational measurement and image analysis, the variation of the wear with slurry concentration has been analyzed to investigate the implicated mechanisms of erosion during the process.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 12 August 2021

Liangjie Mao, Mingjie Cai, Qingyou Liu and Ying Zhang

The purpose of this paper is to study the multi-phase flow behaviors in solid fluidization exploitation of natural gas hydrate (NGH) and its effect on the engineering safety.

Abstract

Purpose

The purpose of this paper is to study the multi-phase flow behaviors in solid fluidization exploitation of natural gas hydrate (NGH) and its effect on the engineering safety.

Design/methodology/approach

In this paper, a multi-phase flow model considering the endothermic decomposition of hydrate is established and finite difference method is used to solve the mathematical model. The model is validated by reproducing the field test data of a well in Shenhu Sea area. Besides, optimization of design parameters is presented to ensure engineering safety during the solid fluidization exploitation of NGH in South China Sea.

Findings

To ensure the engineering safety during solid fluidization exploitation of marine NGH, taking the test well as an example, a drilling flow rate range of 40–50 L/s, drilling fluid density range of 1.2–1.23 g/cm3 and rate of penetration (ROP) range of 10–20 m/h should be recommended. Besides, pre-cooled drilling fluid is also helpful for inhibiting hydrate decomposition.

Originality/value

Systematic research on the effect of multiphase flow behaviors on the engineering safety is scare, especially for the solid fluidization exploitation of NGH in South China Sea. With the growing demand for energy, it is of great significance to ensure the engineering safety before the large-scale extraction of commercial gas from hydrate deposits. The result of this study can provide profound theoretical bases and valuable technical guidance for the commercial solid fluidization exploitation of NGH in South China Sea.

Details

Engineering Computations, vol. 39 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 6 February 2009

Rambabu Arji, D.K. Dwivedi and S.R. Gupta

The paper's aim is to investigate the sand slurry erosive wear behaviour of Ni‐Cr‐Si‐B coating deposited on mild steel by flame spraying process under different test conditions.

Abstract

Purpose

The paper's aim is to investigate the sand slurry erosive wear behaviour of Ni‐Cr‐Si‐B coating deposited on mild steel by flame spraying process under different test conditions.

Design/methodology/approach

Flame sprayed coatings of Ni‐Cr‐Si‐B were developed on mild steel substrate The slurry pot tester was used to evaluate wear behaviour of the coating and mild steel. The erosive wear test was conducted using 20 and 40 per cent silica sand slurry at three rotational speeds (600, 800 and 1,000 rpm).

Findings

Slurry erosive wear of the coating showed that in case of 20 per cent silica sand slurry weight loss increases with increase in rotational speed from 600 to 1,000 rpm while in case of 40 per cent silica sand slurry weight loss first increases with increase in rotational speed from 600 to 800 rpm followed by marginal decrease in weight loss with further increase in rotational speed from 800 to 1,000 rpm. Increase in wear resistance due to thermal spray coating of Ni base alloy on mild steel was quantified as wear ratio (weight loss of mild steel and that of coating under identical erosion test conditions). Wear ratio for Ni‐Cr‐Si‐B coating was found in range of 1.4‐2.8 under different test conditions. The microstructure and microhardness study of coating has been reported and attempts have been to discuss wear behaviour in light of microstructure and microhardness. Scanning electron microscope (SEM) study of wear surface showed that loss of material from the coating surface takes place by indentation, crater formation and lip formation and its fracture.

Practical implications

It would assist in estimating the erosion wear performance of flame sprayed Ni‐Cr coatings and their affects of wear resistance.

Originality/value

Erosion wear of flame sprayed coatings in sand slurry media medium is substantiated by extensive SEM study.

Details

Industrial Lubrication and Tribology, vol. 61 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 25 October 2019

Gurmeet Singh, Satish Kumar, Satbir Singh Sehgal and Shashi Bhushan Prasad

This paper aims to depict the erosion performance of two HVOF-coated micron layers (Colmonoy-88 and Stellite-6) on pump impeller steel (SS-410) by using Taguchi's method…

Abstract

Purpose

This paper aims to depict the erosion performance of two HVOF-coated micron layers (Colmonoy-88 and Stellite-6) on pump impeller steel (SS-410) by using Taguchi's method. Taguchi's array (L16) was used to optimize the erosion wear (in terms of weight loss) by using four influencing parameters such as rotational speed, solid concentration, average particle size and time which were varied at four different levels.

Design/methodology/approach

The experiments were carried out by using a Ducom slurry tester with rotational speed in the range of 750-1,500 rpm, solid concentration of 35-65 per cent by weight, time period of 75-210 min and average particle sizes in the range of < 53 to 250 µm. Bottom Ash with a nominal size range of < 53 to 250 µm was used as erodent. The process parameters were optimized by using Taguchi's method. The ANOVA method was used to validate the results given by Taguchi's method.

Findings

The results revealed that the presence of both carbides and borides and the additional presence of Cr in Colmonoy-88 coating enhancing the slurry erosion resistance of Colmonoy-88 coating. Moreover, the chromium and tungsten carbide particles help in increasing the bond strength between the coating and the substrate material. Further, it was also found that the time was the most dominant factor as compared to other factors.

Originality/value

The very less work has been reported on optimization of erosion wear response of Colmonoy-88 and Stellite-6 coatings by using different design of experiment techniques. Further, the erosion wear mechanism of both coatings has been studied by using image j analysis software.

Details

Industrial Lubrication and Tribology, vol. 72 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 July 1976

J.M. Rackham

A well appreciated difficulty in paint formulation is the scaling‐up of laboratory data, and to obtain optimum performance on a commercial scale adjustments in p.v.c. (f) and in…

Abstract

A well appreciated difficulty in paint formulation is the scaling‐up of laboratory data, and to obtain optimum performance on a commercial scale adjustments in p.v.c. (f) and in resin solids concentration have to be made. In the laboratory the millable p.v.c. (f) of a given formulation may be above, or more usually below, the value indicated by the flowpoint data, and depends mainly on the ability of the particular milling machine to cope with the quantity and nature of the millbase. In large‐scale manufacture using high‐speed shear impellers, a somewhat higher value than the experimentally determined p.v.c. (f) can be used, but for a ballmill it will be only slightly higher than the value millable in the laboratory. The concentration of resin solids has also to be adjusted, and here it is important to ensure that it is high enough to prevent pigment reagglomeration on let‐down.

Details

Pigment & Resin Technology, vol. 5 no. 7
Type: Research Article
ISSN: 0369-9420

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