The general features of zeolites that led to their widespread use in oil refining and petrochemistry are highlighted as well as the details of their impact on selected processes. The analysis of the catalyst market and the position of zeolites therein is a good indication of their strategic importance. Zeolites have brought many disruptive changes to these fields (e.g. FCC). They impacted also these industries in an equally important way, although more subtle, by incremental improvement of processes. The new and vast challenges facing oil refining and petrochemistry as well as the managed transition to sustainable environmental benign transport fuel industries and chemical industries will require creative science and technologies. Zeolites offer the basis of many of these technological solutions provided efficient and balanced cooperations between industry and academia are further developed.

Impact of Zeolites on the Petroleum and Petrochemical Industry

Steam cracking of hydrocarbons has been the major source of light olefins for more than half a century. The recent studies have reported that ethylene and propylene can also be produced through the cracking of hydrocarbons over modified ZSM-5 zeolites in a considerable amount. This paper highlights the important current ideas about acid-catalyzed hydrocarbon cracking that has resulted in high yield of ethylene and propylene. Light olefin production via catalytic cracking of various industrial feedstocks, ranging from heavy hydrocarbons to ethane, over modified ZSM-5 zeolites, has been reviewed in the present paper. Furthermore, the influence of various employed promoters, i.e., alkali and alkaline earth, transition, rare earth elements, and phosphorus, on the chemical properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed. Moreover, the influences of different factors, including the zeolite acidity, Si/Al ratio and the temperature, on the light olefin production and the reaction scheme have been specified. The role of incorporated element in the catalytic cracking mechanism is also summarized.

Catalytic cracking of hydrocarbons over modified ZSM-5 zeolites to produce light olefins: A review

Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes

Oil is nowadays the main energy source and this prevalent position most probably will continue in the next decades. This situation is largely due to the degree of maturity that has been achieved in oil refining and petrochemistry as a consequence of the large effort in research and innovation. The remarkable efficiency of oil refining is largely based on the use of zeolites as catalysts. The use of zeolites as catalysts in refining and petrochemistry has been considered as one of the major accomplishments in the chemistry of the XXth century. In this tutorial review, the introductory part describes the main features of zeolites in connection with their use as solid acids. The main body of the review describes important refining processes in which zeolites are used including light naphtha isomerization, olefin alkylation, reforming, cracking and hydrocracking. The final section contains our view on future developments in the field such as the increase in the quality of the transportation fuels and the coprocessing of increasing percentage of biofuels together with oil streams. This review is intended to provide the rudiments of zeolite science applied to refining catalysis.

Zeolites as catalysts in oil refining

The deactivation of acid zeolite catalysts is essentially due to the formation and trapping of heavy secondary products (coke) within the pores (channels and cages). As in these nanosized pores the growth of these products is sterically limited, the coke composition, i.e., the quantitative distribution in nature and size of the components, can be determined and the scheme and mechanisms of coke formation established. Moreover, coupling activity, acidity and adsorption data with coke composition leads to information on the location and deactivating effect of coke molecules. Based on the influence on coking and deactivation rates of the features of reactions and zeolite catalysts, general rules are proposed for limiting the rate of formation of coke molecules and minimising their deactivating effect.

Prevention of zeolite deactivation by coking

On the mechanism of catalyzed isobutane/butene alkylation by zeolites

Common mechanistic aspects of liquid and solid acid catalyzed alkylation of isobutane with n-butene

On the formation of the acid sites in lanthanum exchanged X zeolites used for isobutane/cis-2-butene alkylation

Deactivation pathways in zeolite-catalyzed isobutane/butene alkylation

This contribution is an in-depth review of chemical and technological aspects of the alkylation of isobutane with light alkenes, focused on the mechanisms operative with both liquid and solid acid catalysts. The differences in importance of the individual mechanistic steps are discussed in terms of the physical–chemical properties of specific catalysts. The impact of important process parameters on alkylation performance is deduced from the mechanism. The established industrial processes based on the application of liquid acids and recent process developments involving solid acid catalysts are described briefly.

Andreas Feller

Papers

On the mechanism of catalyzed isobutane/butene alkylation by zeolites

Common mechanistic aspects of liquid and solid acid catalyzed alkylation of isobutane with n-butene

On the formation of the acid sites in lanthanum exchanged X zeolites used for isobutane/cis-2-butene alkylation

Deactivation pathways in zeolite-catalyzed isobutane/butene alkylation

Chemistry and Technology of Isobutane/Alkene Alkylation Catalyzed by Liquid and Solid Acids