Maximization of propylene in an industrial FCC unit

YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%

Prospects for Direct Natural Gas Conversion to Petrochemical Feedstocks

Natural gas, due to its abundance and low cost, is a major future source as a feedstock for the petroleum and chemical industry. For strategic or economic reasons, it may be undesirable to transport natural gas to potential markets or to use it for transportation fuels. This provides an incentive to investigate various routes to convert natural gas to higher hydrocarbons. Methane, which accounts for over 60% of natural gas, is used today as a source of hydrogen, for ammonia production and to manufacture methanol through steam reforming to the synthesis gas mixtures. However, direct methane conversion to higher hydrocarbon has a high economic incentive as a result of bypassing the synthesis gas step.Recent process development studies have investigated various options for the conversion of natural gas to valuable hydrocarbons. This paper discusses the prospects for direct natural gas conversion by three routes: oxidative coupling to ethylene and higher hydrocarbons, oxidation to methanol or formaldehyde. and oxidation to aromatics by nitrous oxide. Current research activities in the area of natural gas oxidation are reviewed in terms of process conditions, reactor design, catalyst performance in terms of methane conversion and selectivities to various products. Future challenges in reactor and process design for methane oxidation are highlighted

Experimental and kinetic studies of ethyltoluenes production via different alkylation reactions

Ethyltoluenes production via two alkylation reactions vis: toluene ethylation and ethylbenzene (EB) methylation on ZSM-5 and mordenite (MOR) was studied in a batch fluidized-bed reactor at a temperature range of 200-300. °C for reaction times of 5-20. s. Toluene ethylation with ethanol gave better yield and selectivity to ethyltoluenes on ZSM-5 compared with EB methylation with methanol. A maximum ethyltoluenes yield of 22.0% was achieved during toluene ethylation whereas 7.3% yield was attained in EB methylation on ZSM-5. To achieve enhanced para-ethyltoluene selectivity, ZSM-5 was modified by silylation treatment using tetraethyl orthosilicate (TEOS). While toluene conversion on silylated ZSM-5 (HZ80-6L) was decreased, 100% para-isomer selectivity was obtained due to the reduction of the effective pore channel and strength of acid sites. A comprehensive kinetic study of the toluene ethylation reaction is reported in this paper using the power-law approach for the model development. A satisfactory correlation between experimental data and the model result was achieved. The required apparent activation energy for the alkylation step of toluene ethylation reaction over ZSM-5, HZ80-6L and MOR catalysts was determined to be 70. kJ/mol, 63. kJ/mol and 28. kJ/mol, respectively.</p

INTEGRATING REFINING AND PETROCHEMICALS FEEDSTOCKS THROUGH A NOVEL FCC PROCESS

KFUPM has piloted a novel high-severity fluid catalytic cracking (HS-FCC) process that can increase the yield of light olefins to 40wt% of the product, versus the normal 10wt%. The process combines mechanical modifications with changes in process variables and catalyst formulations. The main operating regime of this novel refining process is high reaction temperature, short contact time, high catalyst/oil ratio and a special down-flow reactor system. The paper presents a brief experimental study on the cracking of vacuum gas oil using equilibrated FCC catalyst in a 0.1 bbl/d circulating downer pilot plant. The results show a significant increase in the yield of light olefins, mainly propylene, as well as an improvement in gasoline quality and overall conversion. By adding 10wt% ZSM-5 to the catalyst, the pilot plant yielded 18wt% each of propylene and butylenes or a total increase of 37% compared to base catalyst. A comparative economics of a base refinery (with a conventional FCC) and an upgraded refinery (with HS-FCC) is presented. About 28% of return on investment can be achieved for propylene and para-xylene recovery in the upgraded HS-FCC refinery

Silicalite‑1 As Efficient Catalyst for Production of Propene from 1‑Butene

Reaction of 1-butene was studied over silicalite-1 and H-ZSM-5 zeolites with different Al contents (SiO₂/Al₂O₃ molar ratio (Si/Al₂) = 23, 80, and 280) to explore an efficient catalyst for the formation of propene as well as to elucidate the reaction scheme and the relevant acid sites involved in the reaction. The formation of alkenes, including propene, increased and those of alkanes and aromatics decreased with decreasing Al content. The percentage of alkenes other than <i>n</i>-butene isomers was 60 C-wt % over silicalite-1 at 550 °C with 34.1 C-wt % propene. Over H-ZSM-5 with Si/Al₂ = 23, the formation of alkenes was negligible, and the main products were alkanes and aromatics, the sum of alkanes and aromatics being 65.4 C-wt % at 550 °C. These product distributions are consistently interpreted by the successive reactions of oligomerization, cracking, and hydrogen transfer. For oligomerization and cracking, in addition to strong acid sites on H-ZSM-5 zeolites, weak acid sites present on silicalite-1 act as active sites. For the hydrogen transfer reaction of alkenes to form alkanes and aromatics, strong acid sites are required. The scheme can also be applicable to the reactions of 1-pentene and 1-hexene. The weak acid sites on silicalite-1 are assumed to be the silanol groups that act as Brønsted acid above 300 °C. The presence of strong acid sites on H-ZSM-5 catalysts, which are the OH groups bridging to Si and Al, results in the consumption of alkenes by hydrogen transfer. Removal of a part of Al contained in silicalite-1 as an impurity and enrichment of surface silanol groups on silicalite-1 resulted in the improvement of the propene yield. It is concluded that silicalite-1 is an efficient catalyst for the formation of propene by the reactions of light alkenes because of the absence of strong acid sites and the presence of weak acid sites