4.1 In general, steam treatment of FCC catalyst can be used either to compare a series of cracking catalysts at a simulated equilibrium condition or conditions, or to simulate the equilibrium condition of a specific cracking unit and a specific catalyst. This guide gives an example for the first purpose and an approach for the latter purpose.

1.1 This guide covers the deactivation of fresh fluid catalytic cracking (FCC) catalyst by hydrothermal treatment prior to the determination of the catalytic cracking activity in the microactivity test (MAT).

1.2 The hydrothermal treatment of fresh FCC catalyst, prior to the MAT, is important because the catalytic activity of the catalyst in its fresh state is an inadequate measure of its true commercial performance. During operation in a commercial cracking unit, the catalyst is deactivated by thermal, hydrothermal and chemical degradation. Therefore, to maintain catalytic activity, fresh catalyst is added (semi) continuously to the cracking unit, to replace catalyst lost through the stack or by withdrawal, or both. Under steady state conditions, the catalyst inventory of the unit is called equilibrium catalyst. This catalyst has an activity level substantially below that of fresh catalyst. Therefore, artificially deactivating a fresh catalyst prior to determination of its cracking activity should provide more meaningful catalyst performance data.

1.3 Due to the large variations in properties among fresh FCC catalyst types as well as between commercial cracking unit designs or operating conditions, or both, no single set of steam deactivation conditions is adequate to artificially simulate the equilibrium catalyst for all purposes.

1.4 This guide offers two approaches to steam deactivate fresh catalysts. The first part provides specific sets of conditions (time, temperature and steam pressure) that can be used as general pre-treatments prior to comparison of fresh FCC catalyst MAT activities (Test Method D3907 ) or activities plus selectivities (Test Method D5154 ).

1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.