Modeling the effect of dammar additions on the mass loss response of soy wax/beeswax/dammar blends via response surface methodology

The wax used in the batik industry plays a significant role as its composition dictates the ease of wax rendering, dye layering, and wax removal process. This study aims to evaluate the effect of dammar additions on soy wax/beeswax blends based on the mass loss (%) of the wax-covered cotton fabric in 100°C water. Central composite design (CCD), a subset of response surface methodology (RSM) was used to develop a response model (Y: mass loss %) for three independent variables (X1:beeswax, X2:soy wax, X3:dammar). The final quadratic response model obtained (F value =5.43, lack of fit F value = 4.70, adequate precision = 7.65) was proposed in this study. ANOVA analysis showed that the standard error of design was relatively small, ranging between 0.43 to 1.18 for the design space. It was deduced from the response model, that increasing the dammar content in the soy wax/beeswax blends increases the mass loss (%), possibly due to the compositional inhomogeneity of the blends. The result of this study shows great potentials in formulating new soy wax-based compositions that produce varying degrees of ease of wax removal for the batik industry.

Novel Simulator for Design and Analysis of Wax Removal Treatment from Well Flow Lines Using Thermochemical Fluids

Treatment of well flow lines with thermochemical/exothermic fluid has shown good results for wax removal compared to conventional hot oil, hot water or solvent treatments. However, the technique has not gained widespread use due to lack sufficient scientific publications that can give more insights over its use and help in designing a safe and effective treatment. This paper presents a novel transient mathematical model for design and analysis of thermochemical treatment for well flow lines by taking into account the chemical kinetics, heat transfer, fusion of wax and associated two-phase flow. The governing equations have been solved using tools of computational fluid dynamics and heat transfer (CFD - HT). The resulting simulator can be used to prepare an optimum thermochemical plan by analysing the effects of important factors including wax details, deposition profile, heat loss, formulation composition and injection strategy. Simulation results with the developed model indicate that entire filling of flowline with thermochemical fluid is not necessary for complete wax removal. Injection of a small thermochemical spacer in the flow line followed by its displacement with crude oil can be suffice in case of short flowlines of onshore fields. Selection of initial reactant concentration and pH has to be done judiciously based on the maximum allowed temperature in the flowline and the desired extent of chemical utilization. A sensitivity analysis has shown the existence of an optimum range of injection rate below which wax removal efficiency is compromised by excessive heat loss and above which it is reduced by insufficient residence time. The major limitation of this technique is encountered for large flowlines where a possibility of re-solidification of removed wax deposits exist due to excessive heat loss. Flowlines of length less than 5 km are found to be ideal candidates as in that case, sufficiently high temperatures can be maintained throughout the journey of thermochemical spacer in the flowline which will prevent re-solidification. The simulator has been validated with field implementation results of two well flow lines where the designed jobs have been successful in removing the entire wax deposits as predicted by the simulator.

A New Wax Removal Empirical Model of Fully Coated Foam Pig

Summary Wax deposition is one of the most significant challenges for flow assurance. In a conventional pigging operation, a fully coated foam pig is regularly used to mitigate wax deposition. This work attempts to assess, qualitatively and quantitively, the wax removal process of the fully coated foam pig. The experimental results confirm that the wax removal process of the fully coated foam pig includes four phases; namely, the buildup phase, preplug phase, plug phase, and production phase. Moreover, the effects of coating hardness, wax layer thickness, and the shear strength of wax sample on the wax breaking force and the wax removal efficiency are investigated experimentally. It is found that the wax breaking force decreases and the wax removal efficiency increases when the coating hardness is increased. On the basis of the analysis of the experimental results and Buckingham's π theorem, a semitheoretical model is developed to predict the wax removal efficiency of the fully coated foam pig. Furthermore, a force analysis model is used to calculate the wax breaking force by taking the wax removal efficiency model into account. The average relative errors between the calculated and measured results for the wax removal efficiency and the wax breaking force of the fully coated foam pig with 65 Shore A hardness (HA) coating are 24.13 and 31.88%, respectively. Analogous wax removal models for foam pigs of different types can be developed with the research method proposed in this work. Therefore, this research method provides a general strategy for wax removal research in crude oil pigging.

Optimization of alkali pretreatment conditions for wax removal from bamboo culm

Appropriate chemical reagents were selected for removing the wax layer of bamboo culm, and optimal treatment conditions with the selected agents were determined in this study. Solutions of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium chloride, along with their mixtures with 1% sodium dodecyl sulfate, were tested for efficacy of wax removal on culms of giant timber bamboo (Phyllostachys bambusoides S. et Z.), hachiku bamboo (Phyllostachys nigra var. henosis Stapf), and moso bamboo (Phyllostachys pubescens Mazel). Of the tested reagents, the mixture of potassium hydroxide and sodium dodecyl sulfate showed the best capability. The effects of varying concentrations of the selected reagents and reaction times at 90 °C were investigated by response surface methodology (RSM). Quadratic regression models representing the degree of wax removal at various treatment conditions were determined. The coefficients of determination of the fitted models were greater than 0.98, meaning that the models were highly accurate in predicting the degree of wax removal. According to the fitted models, the optimal conditions of potassium hydroxide concentration, sodium dodecyl sulfate concentration, and reaction time were 5.08%, 3.6%, and 63 min, respectively. The use of an RSM model offers considerable flexibility for practical uses because it allows multiple solutions with any desired level of wax removal.