Methods and systems of monitoring flammability of various streams during vinyl acetate production

A vinyl acetate production process comprising:

• reacting a feed stream comprising acetic acid, ethylene, oxygen, carbon dioxide, alkanes, and water in a reactor to produce a crude vinyl acetate stream comprising vinyl acetate, acetic acid, water, ethylene, carbon dioxide, and alkanes;
• cooling the crude vinyl acetate stream in a heat exchanger;
• measuring and/or determining conditions of a pressure of the feed stream or of the reactor, a temperature of the feed stream or of the reactor, and a concentration of at least one component in the feed stream;
• measuring and/or determining an oxygen content ([O2]) of the feed stream;
• and
• (i) initiating a shutdown procedure or a remedial step when AFLmin>FL−[O2] is true and/or (ii) adjusting the conditions to maintain AFLmin≤FL−[O2], wherein the AFLmin is a minimum approach to flammability limit and the FL is a flammability limit formula, wherein the AFLmin and the FL are based on the conditions, and wherein the FL includes at least one interaction term that represents an interrelation of two or more operating conditions.

A system for producing vinyl acetate, the system comprising:

• a vinyl acetate reactor configured to receive a feed stream line and to produce a crude vinyl acetate stream line;
• a heat exchanger configured to receive the crude vinyl acetate stream line;
• a separator configured to receive the crude vinyl acetate stream line downstream of the heat exchanger and to produce at least two stream lines comprising an overheads stream line and a first bottoms stream line;
• a plurality of sensors comprising an oxygen sensor and one or more of:
• a temperature sensor, a pressure sensor, a flow rate sensor, and a composition sensor, wherein the plurality of sensors are at a location along the system, wherein the oxygen sensor is configured to measure or determine an oxygen content ([O2]);
• and
• a subsystem configured to (i) determine a flammability limit (FL) based on a FL formula and measurements from the plurality of sensors and (ii) determine if AFLmin≤FL−[O2], wherein AFLmin is a minimum approach to flammability limit, and wherein the FL formula includes at least one interaction term that represents an interrelation of two or more operating conditions measured by the plurality of sensors.