Hello Mayursinh,

Process integration is a term in chemical engineering which has two possible meanings.

1. A holistic approach to process design which emphasizes the unity of the process and considers the interactions between different unit operations from the outset, rather than optimising them separately. This can also be called integrated process designor process synthesis. 
2. Pinch analysis, a technique for designing a process to minimise energy consumption and maximise heat recovery, also known as heat integration, energy integration or pinch technology. The technique calculates thermodynamically attainable energy targetsfor a given process and identifies how to achieve them. A key insight is the pinch temperature, which is the most constrained point in the process.