NEW CATALYST DESIGNS MEET ENVIRONMENTAL CHALLENGES OF THE 1990'S

Oct. 1, 1990
Richard A. Corbett Refining/Petrochemical Editor Catalyst manufacturers continue to develop new catalyst formulations designed to meet a wide array of processing challenges. Many of these challenges involve environmental regulations that refiners have been, and will be, required to meet during the 1990's.
Richard A. Corbett
Refining/Petrochemical Editor

Catalyst manufacturers continue to develop new catalyst formulations designed to meet a wide array of processing challenges. Many of these challenges involve environmental regulations that refiners have been, and will be, required to meet during the 1990's.

Manufacturers added more than 75 new catalysts to the Journal's list of refining catalysts, according to the Journal's worldwide survey of catalyst manufacturers and suppliers (see table). Most of these are new formulations that are custom-designed catalyst structures that increase product yields and quality.

The table is limited to only those catalysts that are new offerings since the last publication of the Worldwide Refining Catalyst Compilation -(OGJ, Oct. 2, 1989, p. 46).

Some of these structural changes include changes in silica-alumina ratio and the matrix formulation of FCC catalysts to boost gasoline motor octane number while maintaining gasoline yields. And the new FCC catalysts feature designs to selectively produce more light olefins for alkylation and MTBE production, a significant requirement for the reformulated gasolines that may be mandated during the 1990's.

Hydrotreating catalysts have been improved to meet more stringent specifications on diesel fuel sulfur and aromatics content. These designs are intended to reduce the capital investment required to meet diesel specifications of the 1990's.

There have also been some changes in catalyst manufacturing companies through acquisitions and mergers, such as Akzo Chemicals Inc.'s merger with Filtrol Corp. Akzo and Filtrol are merging their FCC catalyst technologies to develop a wider range of FCC catalyst formulations.

And one new company, heretofore not included in the listing, has been added. Orient Catalyst Co., Tokyo, has been making hydroprocessing catalysts since 1973, but has not previously been listed in the OGJ compilation.

ENVIRONMENTAL ISSUES

Refiners worldwide are being challenged to help improve the world's air quality by producing products that minimize emissions of toxic and hazardous hydrocarbons when they are used. These substances are claimed to be the cause of increased ozone, carbon monoxide, and sulfur dioxide levels in many areas of the world.

As a result, gasoline and diesel formulations have already changed, and will change even more during the 1990's.

Except for rural areas of the U.S., lead has all but disappeared from motor gasoline. This means that octane boosted by the addition of tetra-ethyl lead now has to be boosted through processing means, a good measure of it coming from improved FCC catalyst designs.

Lower vapor pressure gasoline, now required in the U.S. during the summer months, also left an octane debt that had to be made up through processing. And in Europe, lead phasedown is accelerating at a rapid pace, causing refiners there to consider advanced catalyst designs to meet octane requirements.

The reauthorization of the U.S. Clean Air Act of 1970, expected to become law by the end of 1990, will likely require limited aromatics and olefins contents of gasoline formulations (OGJ, June 18, p. 33). Aromatics and olefins are reactive compounds that increase low level ozone levels, especially in the most populated urban areas of the U. S.

Both FCC and catalytic reforming operations will be heavily affected by reductions in aromatics and olefins.

New reforming and FCC catalyst designs are already becoming available to reduce reformer aromatics and FCC heavy olefins.

Clean Air Act reauthorization may also require a minimum oxygen content in gasoline to limit carbon monoxide emissions during winter months in areas where temperature inversions are frequent. This will mean increased blending of oxygenated compounds into gasoline.

Refiners will want to produce their own oxygenated material from existing refinery feedstocks, such as isobutylene for methyl tertiary butyl ether (MTBE) production and isoamylene for tertiary amyl methyl ether (TAME) production. Again, FCC catalysts are being developed to increase yields of the light olefins that can go to MTBE, TAME, and other oxygenate production, and to alkylation units that produce a blend component that does not aggravate emissions.

On the diesel scene, the U.S. has finalized rules that limit the sulfur content of highway diesel fuels. By Oct. 1, 1993, all diesel fuel used in highway vehicles will be limited to 0.05 wt % sulfur and will have to have a minimum cetane number of 40 (OGJ, Aug. 20, p. 40).

Low sulfur and aromatics diesel fuels will put pressure on hydrotreating operations in many refineries, but new hydrotreating catalyst formulations are already beginning to answer that challenge. They do so through improved activity and longer-life formulations that cut sulfur and aromatics in distillate fractions without requiring substantially higher-pressure operation or heavy capital investment in new units.

Subsequent articles in this special report cover some of matrix and zeolite developments in FCC catalysts that will help meet the reformulated fuels era, and on the use of alumina sol catalysts binders to improve motor octane number and reduce the effects of vanadium and nickel in FCC feeds.

A final article shows how reformer feed sulfur reduction to near zero can improve reformer operations, particularly on modern, high-rhenium reforming catalysts.

Copyright 1990 Oil & Gas Journal. All Rights Reserved.