Project Overview:

Hengli Group is a modern textile enterprise with the largest weaving capacity in Asia and ranking among the top three in China's polyester filament production capacity. The Hengli (Dalian Changxing Island) Petrochemical Industrial Base Project invested by Hengli Group is constructed in two phases. Our company undertook the construction of both Phase I and Phase II of the Hengli Petrochemical (Dalian) Co., Ltd. PTA Project demineralized water treatment project. Phase I was completed in December 2012, and Phase II was completed in December 2014. This project is currently the largest demineralized water project in China, with a total treatment capacity of 7.92×10⁴m³/d. This project is also one of our company's demonstration projects for producing demineralized water using the ion exchange method.

Process Overview:

Phase I Industrial and Domestic Water: Mechanical stirring clarifier + V-type filter;

Phase I Demineralized Water: Multi-media filter + Activated carbon filter + Double-chamber cation bed + Decarbonator + Double-chamber anion bed + Primary mixed bed + Secondary mixed bed;

Phase II Primary Demineralized Water: Pretreatment + Multi-media filter + Activated carbon filter + Double-chamber cation bed + Decarbonator + Double-chamber anion bed + Primary mixed bed

Project Scale:

Phase I Industrial and Domestic Water: 2700m³/h

Phase I Primary Demineralized Water: 1800m³/h

Phase I Secondary Demineralized Water: 500m³/h

Phase II Primary Demineralized Water: 1000m³/h

Project Highlights:

The incoming water has low total hardness and low turbidity. Considering the excellent incoming water quality, the ion exchange method is adopted for demineralized water production, offering obvious advantages in construction and operating costs.

Double-chamber ion exchangers are selected, utilizing the large working exchange capacity of the upper weak resin layer to increase the cycle water production. The design cycle water production per unit is 4000 tons, while the actual cycle water production per unit reaches 8000 tons.

The ion exchanger adopts a positive wash water recovery process, reducing the self-consumption water rate. One production cycle can reduce the total self-consumption water by 2500 tons, saving water for the owner, which is beneficial for conserving and recycling resources, and promoting coordinated economic and social development with environmental protection.

The filter operation control mode is optimized by adopting constant water level filtration control. According to the water level changes in each filter group, the outlet regulating valve opening is controlled through PID closed-loop control to achieve basically constant filtration water level, thereby ensuring the realization of process objectives. The filter backwash triggering mode adopts optimized cycle queuing and manual forced triggering settings, achieving intelligent backwash based on differential pressure gauges and effluent turbidity meters.