Project Overview:

The Shenhua Shaanxi Methanol Downstream Processing Project is a key coal-to-olefins project of Shenhua Coal-to-Oil Chemical Co., Ltd. The project is located near Qingshuigou Village, Dabaodang Town, Shenmu County, Yulin City, Shaanxi Province, within the Qingshui Coal Chemical Industrial Park of the Yushen Industrial Zone planned by Shaanxi Province. The project includes a 600,000 tons/year MTO unit, a 600,000 tons/year olefins separation unit, a 300,000 tons/year polyethylene unit, and a 300,000 tons/year polypropylene unit, as well as supporting public utilities and auxiliary facilities such as circulating water systems, wastewater treatment plants, water supply and fire water pump stations, polyolefin packaging warehouses, and comprehensive warehouses. Our company undertook the wastewater and circulating water treatment projects in this project and was awarded the National High-Quality Project Award for 2016-2017.

Process Overview:

Circulating Water: Cooling tower + Combined shallow sand filter

Wastewater: Oil separator + Air flotation + Equalization tank + Hydrolysis acidification tank + Aeration tank + MBR

Project Scale:

Circulating Water: Circulating water supply system 1 with water supply capacity: 4.05×10⁴m³/h, Circulating water supply system 2 with water supply capacity: 0.60×10⁴m³/h

Wastewater: 350m³/h

Project Highlights:

Circulating Water: In response to the low winter temperatures in Yulin, lessons from operational failures of similar cooling towers in the local area were summarized. In this project, optimizations were made to details such as the enclosure structure of the cooling tower, pipeline icing prevention, air and water distribution, ensuring normal operation of the system under harsh winter weather conditions. The cooling tower fans adopt reliable low-energy-consumption designs, flow field homogenization technology, and CFD design technology, resulting in low wind resistance inside the tower, low fan shaft power, and power consumption ratio far below the national standard of 0.045kW/(m³/h). The side filtration system uses imported shallow sand filters from Israel, ensuring effluent quality meets standards under high-load operation conditions, significantly solving problems in similar projects such as large footprint of the side filtration system, high backwash water consumption, and high power consumption. Backwash water for the side filtration system uses multiple sources, including high-quality reclaimed water, production water, post-filtration produced water, and demineralized water, allowing flexible adjustment based on changes in raw water quality and operating conditions.

Wastewater: Adopts flat-flow oil separator + two-stage air flotation pretreatment to effectively remove oil and suspended solids from wastewater; uses hydrolysis acidification + aeration tank + MBR process to effectively degrade COD and ammonia nitrogen in MTO wastewater; MBR effluent meets primary reclaimed water quality requirements and can be directly used as makeup water for circulating cooling water.