Pressure-based method to determine instability temperature

An analytic method comprising:

• heating a chemical sample within a pressure chamber, wherein the heating is according to at least a portion of a predetermined heating process;
• measuring a pressure within the pressure vessel while heating the chemical sample to produce pressure data;
• measuring a temperature of the chemical sample while heating the chemical sample to produce sample temperature data;
• identifying in the pressure data a pressure inflection point associated with a sustained pressure increase;
• and
• processing the sample temperature data to determine a stability temperature of the chemical sample, wherein the stability temperature is the temperature of the chemical sample associated with a minimum pressure of the identified sustained pressure increase.

A method of operating an alkylation reactor, the method comprising:

• obtaining an acid solution sample from an acid solution;
• heating the acid solution sample within a calorimetric device, wherein the heating is controlled by a computer-implemented program applying heat to the calorimetric device according to a rate defined in at least a portion of a predetermined heating process;
• measuring a pressure within the calorimetric device while heating the acid solution sample;
• measuring a temperature of the acid solution sample while applying heat according to the computer-implemented program;
• identifying a pressure inflection point in the pressure data recorded during the heating program wherein after the pressure inflection point is a sustained pressure increase;
• identifying the temperature at the identified pressure inflection point;
• determining stability of the acid solution sample at a predetermined temperature according to the identified pressure inflection temperature and the predetermined threshold temperature;
• and
• adjusting a feed composition to the alkylation reactor according to the determined stability of the acid solution sample.