Patent ID: 7015174

Claim:
A method of protecting activated metalloaluminophosphate molecular sieve from loss of catalytic activity, comprising contacting the activated metalloaluminophosphate molecular sieve with a gas containing water at a temperature and water partial pressure effective to maintain a predetermined catalytic activity index, wherein the catalytic activity index is represented by the formula: CAI =exp( f ( T )* f ( PP water ) n *alpha* t ) wherein t=time of contact of catalyst with water (hours) T=temperature at contact (° C.) PP water =Partial Pressure of water in contact gas (psia) alpha=−0.071 n=3.5 f(T)=exp(ea(1/(T+273)−1/(T o +273))) ea=−5500° K T o =2000° C. f(PP water )=(26.2*PP water +1.14)*0.175, for T≧180° C. (453° K) f(PP water )=((26.2+0.272*(180−T))*PP water /P sat +1.14)*0.175, for 180° C. (453° K)>T≧150° C. (433° K) P sat =Saturation pressure of water at T (psia).