Organic Rankine cycle based conversion of gas processing plant waste heat into power and cooling

A method comprising:

• heating a heating fluid stream via a waste heat recovery exchanger by exchange with a heat source in a crude oil associated gas processing plant;
• generating power and cooling capacity in an Organic Rankine cycle energy conversion system, comprising:
• heating a first portion of a working fluid by exchange with the heated heating fluid stream via an energy conversion heat exchanger, the working fluid comprising iso-butane;
• cooling one or more of a process stream from the crude oil associated gas processing plant and a cooling water stream for ambient air cooling by exchange with a second portion of the working fluid in a cooling subsystem;
• in an ejector, combining the second portion of the working fluid from the cooling subsystem and a third portion of the working fluid, the third portion of the working fluid being a portion of the heated first portion of the working fluid;
• adjusting with the ejector a ratio of an amount of working fluid in the third portion of the working fluid and an amount of working fluid in the fourth portion of the working fluid;
• generating power by expansion of a fourth portion of the working fluid in a turbine coupled to a generator, the fourth portion of the working fluid being a portion of the heated first portion of the working fluid;
• and
• cooling, in a cooling element, a stream of working fluid including an output stream of working fluid from the ejector and the expanded fourth portion of the working fluid from the turbine coupled to the generator.