Compound catalyst market

Figure 2.1 Estimated trend of catalyst market in markets in billion euro. CAGR Compound annual growth rate. Source adapted from Smith [49].

The main components of FCC catalysts are Zeolite Y, e.g., REY orUSY as the major active component (10 to 50%), and a binder that is typically an amorphous alumina, silica-alumina, or clay material. In addition to these main components, other zeolite components, e.g., ZSM-5, and other oxide or salt components are quite frequently used additives in the various FCC catalysts available on the market. The addition of 1 to 5% ZSM-5 increases the octane number of the gasoline. ZSM-5 eliminates feed compounds with low octane numbers because it preferentially center-cracks n-paraffins producing butene and propene [14], These short-chain olefins are then used as alkylation feedstocks... 

Before 1970 there was very little unleaded gasoline on the market, but by 1974 all gas stations were offering it. In 1974, unleaded fuel had become a necessity for most new cars because of their catalytic converters placed in the exhaust system. These contain platinum or palladium compounds that act as a surface catalyst to bum the hydrocarbons more completely. But lead coats the platinum and palladium and deactivates the converters, so unleaded gas must be used. Up to 4 g/gal of lead could be used in the 1970s, but this was decreased to 0.1 g by 1986. Since 1995 no leaded gas could be used in the U.S. Fig. 7.6 shows the dramatic shift from leaded to unleaded gas between 1975 and 1992. 

CO is derived from a variety of feedstocks such as petroleum gas, fuel oil, coal, and biomass. The industrial scale production of PO starts from propylene, which is mainly obtained from crude oil. However, due to the high importance of this compound, many pathways from renewable sources have additionally been developed [54]. PP is converted to PO by either hydrochlorination or oxidation [55]. The use of chlorine leads to large amounts of salts as by-products, therefore oxidation methods are more important, such as the co-oxidation of PP using ethylbenzene or isobutene in the presence of air and a catalyst. However, this process is economically dependent on the market share of these by-products, thus new procedures without significant amounts of other side-products have been developed, such as the HPPO (hydrogen peroxide to propylene oxide) process in which propylene is oxidized with hydrogen peroxide to give PO and water [56, 57] (Fig. 14). 

Utilities using post-combustion SCR-supported ammonia injection for NOx control as well as those using ammonia conditioning to improve electrostatic precipitator performance will produce fly ash that contains ammonia compounds. The ammonia is primarily physically adsorbed onto the fly ash particles as sulphate and bisulphate species. In many cases, the residual ammonia levels are quite low (<50ppm) however, elevated concentrations can occur as the catalyst ages or due to mechanical problems with the ammonia injection system. While elevated ammonia concentrations in fly ash do not negatively impact pozzolanic properties, it can reduce ash marketability due to odour concerns. For this reason, several processes have been developed to remove or reduce the amount of ammonia in fly ash. 

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