*2.1.2 Regeneration column profile*

Triethylene glycol is recovered in a distillation column containing a reboiler and a condenser. The reboiler temperature is 205°C to avoid decomposition of the glycol, and the condenser is at 102°C because the boiling point of water is 100°C. The reboiler is pressurized to below atmospheric pressure to increase the glycol purity. Under these conditions, glycol is recovered by 98.06% in molar percentage or 99.10% in mass percentage (**Table 6**).

### **2.2 Analysis and optimization of absorption process**

An analysis of the various parameters involved in the absorption process will allow us to better understand the effect of these variables on the process. The result of this analysis will allow us to select variable parameters to obtain the most optimal process. The most important process parameters are the solvent flow rate in the absorber, the gas contact temperature, the number of equilibrium stages in the absorber, and the stripping gas used (if a very concentrated TEG is required).

### *2.2.1 Influence of TEG flow rate on dry gas content*

To determine the influence of the number of equilibrium stages in the absorber, as well as the TEG flow, the feed gas is taken into account and the TEG flow rate and the number of stages are varied. The water content of the gas will be calculated for each option. The TEG flow rate was varied between 1500 and 3000 kg/h (**Figure 2**).

The result of the analysis shows that the water content in the dry gas decreases with an increase in the circulation rate of the triethylene glycol.

It can be seen that starting from 1500 kg/h, the water content in the gas is 0.019 g/m<sup>3</sup> , and with an increase in the TEG consumption, the water content decreases.

With regard to the optimization of the TEG circulation, it can be seen that 1700 kg/h allows a water content of 0.015 g/m<sup>3</sup> to be achieved, which corresponds to the specification for the water content in the gas. Therefore, it is preferable to reduce the amount from 2500 to 1700 kg/h and it will be more cost-effective from an economic point of view.

**Figure 2.** *Influence of TEG flow rate on dry gas content.*

*Analysis of Efficiency of Natural Gas Absorption Process from Water Impurities DOI: http://dx.doi.org/10.5772/intechopen.100417*

**Figure 3.** *Influence of gas contact temperature on water dew point.*

In addition, high circulation rates can overload the reboiler and prevent proper glycol regeneration. The heat required for the reboiler is directly proportional to the circulation rate. Thus, increasing the circulation rate can lower the reboiler temperature, reduce the lean glycol concentration, and actually reduce the amount of water that the glycol removes from the gas.
