Comparison of the anti-coking performance of CVD TiN, TiO 2  and TiC coatings for hydrocarbon fuel pyrolysis

Tang, Shiyun; Shi, Ning; Wang, Jianli; Tang, Anjiang

doi:10.1016/j.ceramint.2016.12.036

Cited by 26 publications

(7 citation statements)

References 36 publications

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“…Therefore, no a priori connection can be made between the effects of adding an element in the reactor material and its coking tendency. The anticoking performance of titanium oxide and TiC coatings in hydrocarbon pyrolysis has been reported previously [35]. However, the use of a Ti–base alloy in stream cracking reactors has not been evaluated yet.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Ti–Base Alloy as Steam Cracking Reactor Material

2019

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Low-coking reactor material technologies are key for improving the performance and sustainability of steam crackers. In an attempt to appraise the coking performance of an alternative Ti–base alloy during ethane steam cracking, an experimental study was performed in a jet stirred reactor under industrially relevant conditions using thermogravimetry (Tgasphase = 1173 K, Ptot = 0.1 MPa, XC2H6 = 70%, and dilution δ = 0.33 kgH2O/kgHC). Initially, a typical pretreatment used for Fe–Ni–Cr alloys was utilized and compared with a pretreatment at increased temperature, aiming at better surface oxidation and thus suppressing coke formation. The results revealed a decrease in coking rates upon high temperature pretreatment of the Ti–base alloy, however, its coking performance was significantly worse compared to the typically used Fe–Ni–Cr alloys, and carbon oxides formation increased by a factor of 30 or more. Moreover, the analyzed coupons showed crack propagation after coking/decoking and cooling down to ambient temperature. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy indicated that the prompt and unsystematic oxidation of the surface and bulk caused observable crack initiation and propagation due to alloy brittleness. Hence, the tested Ti–base alloy cannot be considered an industrially noteworthy steam cracking reactor alloy.

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Section: Introductionmentioning

confidence: 99%

Evaluation of a Ti–Base Alloy as Steam Cracking Reactor Material

2019

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“…Their result showed that the anti-coking performance of the MnCr 2 O 4 spinel coating exceeded 60% during the thermal cracking of light naphtha. In previous works, the anti-coking performances of TiN, TiO 2 , and TiC coatings were investigated [14][15][16][17]. The results show that TiN, TiO 2 , and TiC coatings have an obvious anti-coking effect; especially, the anti-coking performance of the TiN coating exceed 90%, and the anti-coking effect of the coatings vary in the order TiN = TiC > TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Comparison of Growth Characteristics and Properties of CVD TiN and TiO2 Anti-Coking Coatings

et al. 2019

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Coating metals with anti-coking materials inhibit their catalytic coking and are especially beneficial in the pyrolysis of hydrocarbon fuels. It is believed that growth characteristics and properties may play a pivotal role in the anti-coking performance of chemical vapor deposition (CVD) coatings. In this study, TiN and TiO 2 coatings were obtained by CVD using TiCl 4 -N 2 -H 2 and TiCl 4 -H 2 -CO 2 systems, respectively. The effects of deposition time, residence time, and partial pressure were examined, and the coating microstructure was characterized by scanning electron microscopy (SEM). The results reveal that the effect of deposition parameters on the growth characteristics of TiN and TiO 2 coatings is very different. The growth of the TiN coating shows characteristics of the island growth model, while the TiO 2 coating follows the layer model. In general, the growth rate of the star-shaped TiN crystals is higher than that of crystals of other shapes. For the TiO 2 coating, the layer mode growth characteristics indicate that the morphology of the TiO 2 coating does not change significantly with the experimental conditions. Coking tests showed that the morphology of non-catalytic cokes is not only affected by the temperature, pressure, and coking precursor, but is also closely related to the surface state of the coatings. Both TiN and TiO 2 coatings can effectively prevent catalytic coking and eliminate filamentous cokes. In some cases, however, the N or O atoms in the TiN and TiO 2 coatings may affect common carbon deposits formed by non-catalytic coking, such as formation of needle-like and flaky carbon deposits.

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“…Up to now, the on‐line coatings mainly include the alkali or alkaline earth metal coatings, 7 SiO 2 /S coating, 8,9 high‐temperature atmosphere oxidation coating, 10,11 and glass coating 12 . The off‐line coating mainly includes Al 2 O 3 coating prepared by powder embedding, 13 the alloy coating using physical vapor deposition and plasma‐enhanced chemical deposition, 14 TiO 2 , TiC, and TiN coating by chemical vapor deposition, 15–18 and the plasma treatment technology (PTT) coating by powder metallurgy and plasma welding technology 19…”

Section: Introductionmentioning

confidence: 99%

Ti–Mn coating prepared by tungsten inert gas cladding and its inhibiting coking property

Wang

et al. 2020

Asia-Pacific J Chem Eng

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The Ti–Mn cladding layers with different ratios were prepared on the surface of 310S steel using tungsten inert gas (TIG) technology for inhibiting coking in ethylene cracking, and the cladding specimens were oxidized by muffle furnace for 10 h at 800°C. The coking evaluation tests of the oxidized specimens with different Ti–Mn powder ratios were carried out with light naphtha at 850°C. The results show that when the ratio of Ti to Mn was 3:1, a protective layer of TiO2–TinO2n‐1–Mn5O8 was formed on the surface of specimen, and with the decrease of Ti element content, unstable Fe‐Ti spinel compounds appeared on the surface. When the ratio of Ti to Mn is 1:3, 1:2, and 1:1, the coking inhibition rate was 40%, 46%, and 59%, respectively. Catalytic coke formed on the surface of coating. When the ratio of Ti to Mn was 3:1, the inhibiting coking rate on the surface of the coating reached 80%, and the inhibiting coking performance was optimal, which inhibited the catalytic coking of Fe and Ni metal particles. With the increase of Ti content and the decrease of Mn content, the graphitization degree of coke decreased according to Raman spectrum.

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Comparison of the anti-coking performance of CVD TiN, TiO 2 and TiC coatings for hydrocarbon fuel pyrolysis

Cited by 26 publications

References 36 publications

Evaluation of a Ti–Base Alloy as Steam Cracking Reactor Material

Evaluation of a Ti–Base Alloy as Steam Cracking Reactor Material

Comparison of Growth Characteristics and Properties of CVD TiN and TiO2 Anti-Coking Coatings

Ti–Mn coating prepared by tungsten inert gas cladding and its inhibiting coking property

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