I. Project Overview
1.1 Basic Project Information
Implementation Unit: A medium-sized domestic refining and chemical enterprise, mainly engaged in crude oil processing and production of refined oil products and chemical by-products.
Attached Unit: 3 million TPY atmospheric and vacuum distillation unit, the core primary fractionation unit of a refinery, which produces gasoline, diesel oil, wax oil and other intermediate products.
Project Type: Renovation project of replacing old water cooling system and constructing new high-efficiency air cooling system.
Project Duration: Total construction period of 6 months, including 1.5 months for design, 2 months for equipment manufacturing, 1.5 months for installation and commissioning, and 1 month for trial operation and acceptance.
Core Objectives: Replace high water-consuming and low-efficiency circulating water coolers, solve core problems including cooling bottlenecks, water resource waste, and serious equipment corrosion and fouling, realize energy saving, water saving and long-term stable operation of the cooling system, and ensure full-load production of the distillation unit.
1.2 Project Background and Original Pain Points
The original cooling mode of the unit was "water cooling as the main method, air cooling as the auxiliary method", and the key link of overhead oil-gas cooling relied on circulating water coolers. After 3 years of operation, prominent problems restricted stable production:
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High Water Consumption and Cost: Daily fresh water replenishment reached about 120m³, circulating water required regular blowdown and chemical dosing, leading to high water treatment costs and failure to meet industrial water conservation and emission reduction requirements.
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Poor Cooling Stability: In summer, the temperature of circulating water rose, reducing heat exchange efficiency; the cooled temperature of overhead oil-gas exceeded the standard, lowering light component recovery rate and forcing the unit load to be reduced by 5%-8%.
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Frequent Corrosion and Fouling: Corrosive media such as H₂S and Cl⁻ in crude oil, combined with water impurities, caused serious tube bundle fouling and pitting corrosion. Shutdown cleaning was required every 3 months, and tube bundles were replaced at least twice a year, resulting in frequent unplanned shutdowns.
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High Energy Consumption and Maintenance Cost: Circulating water pumps and cooling tower fans operated at full load for a long time with high power consumption; coupled with costs for equipment cleaning, maintenance and water treatment, the overall economic efficiency was poor.
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To solve the above problems thoroughly, the enterprise adopted a combined scheme of dry-type air coolers + spray humidification composite air coolers to completely replace water cooling equipment and build a water-saving and high-efficiency process cooling system.
