Recovering energy from flue gas by using a utilities grid technique

•The utilities grid technique used for recovering energy from flue gas.•The technique minimises the amount of heat flow rate loss.•It searches for more appropriate allocations of heating non-process streams.

The effect of industrial activity on the environment has attracted increasing attention over recent decades. Industry has therefore started looking at methods of reducing the mass flow rates of utilities. This has resulted in extensive research into developing various recovery methods for in-plant utilities, thereby reducing the overall mass flow rates of utilities.This paper focuses on an effective application regarding utilities and available heat flow rate for recovering energy by using a utilities grid technique, which•minimises the amount of heat flow rate loss•searches for more appropriate allocations of heating non-process streams.The research idea, which is presented using a utilities grid technique, is founded on the heat flow rate of the flue gas and the available heat flow rate being produced for steam generation and air heating regarding combustion along a furnace-channel without changing the basic process operation. The goal of the utilities grid technique is to search for more appropriate allocations of heating non-process streams by using the mathematical method.This technique has been tested on an existing methanol process that allows for efficient air heating and an additional 4.4% of steam production.