Study of Phase Transition in Hard Microcrystalline Waxes and Wax Blends by Differential Scanning Calorimetry

Kumar, Sanat; Agrawal, K. M.; Khan, H. U.; Sikora, Antonín

doi:10.1081/lft-120024390

Cited by 21 publications

(9 citation statements)

References 7 publications

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“…In some industries wax with low melting point is desired and vice versa for others. DSC has been widely used to characterize different petroleum waxes [17]. As seen in Fig.…”

Section: Characterization Of Paraffin Wax and Znstmentioning

confidence: 99%

“…1 (curve 1), the paraffin sample that was used, has two endothermic peaks that represent solid-solid and solid-liquid transitions on the DSC curve. The peaks at 39 and 57°C belong to orthorhombic to hexagonal transition and solid-liquid transition, respectively [17]. Oil content is also an effective property that influences the melting point of the wax.…”

Section: Characterization Of Paraffin Wax and Znstmentioning

confidence: 99%

See 1 more Smart Citation

The effect of zinc stearate on thermal degradation of paraffin wax

Gönen

Balköse

İnal

et al. 2008

J Therm Anal Calorim

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Petroleum waxes are complex mixtures of high molecular mass saturated hydrocarbons. These hydrocarbon mixtures mainly consist of n-, iso-, and cyclo-alkanes and traces of aromatic and hetero-analogous compounds in the range of C16-C65 [1,2]. They are mainly divided into two groups, macrocrystalline and microcrystalline waxes, according to their structural constituents. In refining industry, waxes are obtained as a by-product in lubricating oil manufacturing process. As paraffin waxes have excellent properties, such as water-repellency and lubricity they find a wide range of applications including paper and chipboard production, packaging materials, cosmetic and pharmaceutical industries, and plastic industries [2]. Apart from these, they are also used as a component of binder system in ceramic processing, metal powder molding and metal injection molding [3,4]. A technical grade paraffin wax was used as phase change material in deposition of solar energy due to its high latent heat of melting (i.e., 190 kJ kg -1 ) [5]. In most of its applications, thermal decomposition takes place during processing or sintering, such as ceramic or metal powder molding. Another use of paraffin wax is solid fuel for rocket systems. Recently, it has been studied as a high regression rate propellant. It is a candidate for rocket solid fuel, which is expected to replace the conventional rocket fuels, such as cryogenic combustible gases; polymethyl methacrylate (PMMA), high density polyethylene (HDPE), due to its low cost, reduced complexity and increased performance. It has been pointed out that paraffin wax regression rate is about 0.100 cm -1 , which is five times greater than the other solid hybrid fuels [6]. The thermal decomposition kinetics of RP-1 rocket propellant, which consists of paraffins, olefins and aromatics, was investigated between 375-500°C. Thermal decomposition kinetics of RP-1 was assumed to occur by first order reaction [7].Paraffin molecules having different chain length behave similarly towards most of the reactants under similar reaction conditions. When they are heated, they start to degrade into smaller chain lengths. The degradation of petroleum based material is assumed as first order reactions [8].The chain length can be decreased by high temperature treatment and solids having metal ions that act as catalysts. Paraffins in oxidizing media at high temperature undergo simultaneous pyrolysis and oxidation reactions. Pyrolysis of n-hexadecane, considered as paraffinic substance, was studied by Watanabe et al. at 500-550°C in a batch type closed reactor [9]. There were five elementary reaction groups in the pyrolysis of n-hexadecane; initiation, isomerization, b-scission, H-abstraction and termination. In this mechanism, n-alkanes were produced from H-abstraction and l-alkenes are formed via b-scission [9]. Polyethylene which is a polymeric paraffin was converted to liquid and wax products using zeolite with concentrations up to maximum mass by 50% [10]. Organometallic compounds are added to fuels in small qu...

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“…In some industries wax with low melting point is desired and vice versa for others. DSC has been widely used to characterize different petroleum waxes [17]. As seen in Fig.…”

Section: Characterization Of Paraffin Wax and Znstmentioning

confidence: 99%

Section: Characterization Of Paraffin Wax and Znstmentioning

confidence: 99%

The effect of zinc stearate on thermal degradation of paraffin wax

Gönen

Balköse

İnal

et al. 2008

J Therm Anal Calorim

View full text Add to dashboard Cite

show abstract

“…Traditionally oils have been paraffin based if paraffin wax would separate from the oil on cooling and asphalt based if there was no separation of paraffin wax. In more recent years this has been replaced by referring to the wax itself as either being macrocrystalline or microcrystalline (Kumar et al 2004;Dorset 2000;Elsharkawy et al 2000). Macrocrystalline wax is the most familiar as it is composed of mostly straight chain paraffins with microcrystalline waxes being composed of high amounts of naphthenic and iso-paraffinic components (Dorset 2000;Elsharkawy et al 2000).…”

Section: Wax Classificationmentioning

confidence: 99%

“…Macrocrystalline wax is the most familiar as it is composed of mostly straight chain paraffins with microcrystalline waxes being composed of high amounts of naphthenic and iso-paraffinic components (Dorset 2000;Elsharkawy et al 2000). In some publications macrocrystalline waxes are simply referred to as paraffin waxes and microcrystalline waxes are known as amorphous waxes or mal-crystals (Kumar et al 2004;Elsharkawy et al 2000;Dorset 2000).…”

Section: Wax Classificationmentioning

confidence: 99%

Using Cross-Polarized Microscopy to Optimize Wax-Treatment Methods

Bacon

Romero‐Zerón

Chong

2009

SPE Annual Technical Conference and Exhibition

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Paraffin wax deposits are known to be a worldwide problem in the upstream petroleum industry. Considerable resources are expended on inhibiting or removing wax deposits every year. Paraffin wax is not the only type of crude oil based wax. Microcrystalline waxes, composed of naphthene and iso-paraffin molecules, also exist but are not well studied. The predominance of paraffin (also called macrocrystalline) wax and paraffin wax inhibition techniques will likely lead to paraffin wax treatments being applied to naphthene based reservoirs. It is unclear how well a paraffin based treatment will apply to naphthene based oil.The current study investigates the use of Cross-Polarized Microscopy (CPM) to determine if a crude oil contains macrocrystalline or microcrystalline waxes. CPM can determine the size and morphology of wax crystals because crude oil wax crystals are known to be anisotropic. Macrocrystalline waxes are known to present with larger, elongated structures while microcrystalline waxes present with smaller, rounded structures. The type of wax present in the crude oil can be determined using crystal morphology and size. Knowing which type of wax is present in the oil will help to choose which type of wax inhibitor will be used. This study has shown that CPM can be an effective tool to determine the type of wax present in a crude oil. Paraffin wax crystals are shown as being elongated structures with statistically larger sizes than the microcrystals. Microcrystalline waxes are shown to be statistically smaller and rounded structures. CPM is a simple, costeffective method that can be used in addition to standard tests to determine if a crude oil is paraffin or naphthene based. In the future this test can be used to prevent paraffin wax treatments being applied to naphthene based reservoirs and to help optimize the specific inhibitor chosen.

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“…Therefore, sole dependency on temperature measurement alone may lead to an incorrect estimation of the stored energy in the PCM, particularly in a large PCM-based energy storage system. To address this issue, several techniques such as differential scanning calorimetry (DSC) [8] and differential thermal analysis (DTA) [9] have been proposed to determine the phase state of PCM. However, these techniques are complex to operate which usually requires a skilled technician to carry out measurement and costly.…”

Section: Introductionmentioning

confidence: 99%

Optical fibre sensors for monitoring phase transitions in phase changing materials

Kumar¹,

Han²,

Liu³

et al. 2018

Smart Mater. Struct.

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A platinum coated singlemode-multimode (SM) structure is investigated in this paper as an optical fibre sensor (OFS) to monitor the phase transition of a phase change material (PCM). Paraffin wax has been used as an example to demonstrate the sensor's performance and operation. Most materials have the same temperature but different thermal energy levels during the phase change process, therefore, sole dependency on temperature measurement may lead to an incorrect estimation of the stored energy in PCM. The output spectrum of the reflected light from the OFS is very sensitive to the bend introduced by the PCM where both liquid and solid states exist during the phase transition. The measurement of strain experienced by the OFS during the phase change of the PCM is utilized for identifying the phase transition of paraffin wax between the solid and liquid states. The experimental results presented in this paper show that the OFS with a shorter multimode fibre section has better performance for monitoring the phase transition of paraffin wax with a measured phase transition temperature range of 41.5°C-57.7°C for the SM based OFS with a 5 mm long multimode fibre section.

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Study of Phase Transition in Hard Microcrystalline Waxes and Wax Blends by Differential Scanning Calorimetry

Cited by 21 publications

References 7 publications

The effect of zinc stearate on thermal degradation of paraffin wax

The effect of zinc stearate on thermal degradation of paraffin wax

Using Cross-Polarized Microscopy to Optimize Wax-Treatment Methods

Optical fibre sensors for monitoring phase transitions in phase changing materials

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