Isfahan Northern Hybrid Refinery Cooling Tower

Project Overview

Given the country’s water crisis and the difficulties faced by the Isfahan Refinery in supplying raw water for consumption in existing wet cooling towers, the refinery decided to build a hybrid cooling tower to reduce water losses and evaporation. Given the history and expertise of Kayson Water and Environment, the design and construction of the hybrid cooling tower was entrusted to them. Considering the tower’s capacity, the temperature of the returned hot water, the required temperature of the cooled water, and the refinery’s target rate of evaporation reduction, the design of the hybrid cooling tower is unique in the world. In addition to meeting the temperature parameters and the rate of evaporation reduction, the tower’s design also required optimal energy consumption and the limited space available for its construction. By launching this tower, the water evaporation rate will be reduced by 5 percent, equivalent to one million cubic meters per year, which will significantly contribute to the preservation of the region’s precious groundwater resources.

Scope of Work

Design, procurement, supply of materials and equipment, installation, all tests, commissioning and provisional and final acceptance of a hybrid cooling tower by EPC method in the northern refinery of Isfahan Oil Refining Company.

Process Description

Unlike wet cooling towers, which cool solely by evaporation, in the hybrid tower, the hot water is first cooled to its maximum temperature using closed-loop air exchangers, without evaporation. If necessary, the water in the wet section of the tower is then cooled to the desired temperature. With a capacity of 14,000 cubic meters per hour, this tower cools the hot water from the refinery’s processing units from a temperature of 34°C to 23°C, then returns it to the aforementioned units via the installed pumping station. To remove physical contaminants from the cooling water, an automatic sidewall filtration system was integrated into the process. Chemical solutions were also provided to adjust the pH, prevent sedimentation, and inhibit the growth of microorganisms, which inject the necessary quantities of chemicals into the water. In order to achieve maximum reduction of water evaporation and also optimize energy consumption, the electric motors of the tower fans and electric pumps are equipped with a VFD system.

Project Statistics

Excavation	24,000 m³
Reinforcement	1,200 t
Formwork	32,185 m²
Main concreting	10,400 m³
Additional concreting	4,025 m²
GRP pipes	11,989 m
Metal pipes (carbon steel)	13,500 m
Cooling tower capacity	14,000 m³/hr
Hot water temperature	34 C°
Cooling water temperature	23 C°
Recovery water saving rate	One million cubic meters per year
Tower structure	Concrete
Feed water pumps	3 electric pump units with a capacity of 2 MW each, equipped with a frequency inverter
Fans	10 electric fan units equipped with a frequency converter
Transformers	2 sets of 6 kV, 2 sets of 33 kV