Methods and systems for operating a pump at an efficiency point

An in-line fluid mixing system positioned at a tank farm to admix hydrocarbon liquids from a plurality of tanks into a single pipeline, the in-line fluid mixing system comprising:

• a first tank positioned at a tank farm containing a first fluid therein;
• a pump in fluid communication with the tank and configured to control a flow rate of the first fluid from the tank;
• a main control valve to receive a first portion of the first fluid from the pump and configured to control a flow rate of the first portion of the first fluid to a mixing pipe;
• a spillback loop including a spillback control valve configured to control the flow rate of the first fluid by diverting a second portion of the first fluid from the pump and diverting the second portion of the first fluid back to the pump such that the pump consumes less energy, the second portion of the first fluid based on a difference of:
• (1) a best efficiency point of the pump on a pump curve and (2) a current pump efficiency point of the pump on the pump curve defined by the best efficiency point and pump speed;
• and
• a second tank positioned at the tank farm containing a second fluid therein and in fluid communication with the mixing pipe to thereby transport the second fluid to the mixing pipe to form a mixture with the first portion of the first fluid and the second fluid.

A pump efficiency point operation system positioned at a tank farm to drive a pump to operate at an efficiency point, the system comprising:

• a tank positioned at a tank farm containing a fluid therein;
• a pump including an input and an output, the input of the pump connected to the tank, the pump to control flow rate of a first fluid from the tank;
• a main control valve connected to the pump and to further control flow rate of the first fluid from the pump to a mixing pipe;
• and
• a spillback loop connected upstream of the pump and downstream of the pump, the spillback loop including a spillback control valve to control flow rate of the fluid by diverting a portion of the fluid from the output of the pump to the input of the pump to drive the pump to consume less energy, the diverted portion of the fluid based on a difference between a best efficiency point on a pump curve and a current pump efficiency point and speed of the pump on the pump curve.