5.1 Desulfurization process system

5.1.1 Main design principles of process system

The desulfurization process adopts wet desulfurization;

The flue gas treatment capacity of the desulfurization device is 30% to 100% of the flue gas volume under BMCR conditions;

Under design conditions, the guaranteed desulfurization efficiency of the absorption tower shall not be less than 80%;

The annual utilization hours of desulfurization equipment are considered to be 7200 hours;

The guaranteed utilization rate of the FGD device is not less than 98%;

The flue gas desulfurization system is convenient for daily inspection, normal maintenance, upkeep, and annual repair.

5.1.2 Main Performance Guarantee of Process System

The desulfurization guarantee efficiency is ≥ 90%,

Export SO2 emission concentration ≤ 100 mg/Nm3

Export smoke emission concentration ≤ 30 mg/Nm3

Desulfurization system Ca/S ≤ 1.15 mol/mol

The pressure drop of flue gas passing through the desulfurization system is ≤ 600 Pa

The noise level of the desulfurization system equipment shall not exceed 85 dB (A) (tested at a distance of 1m from the equipment and 1.2m from the operating platform)

The availability rate of desulfurization system equipment shall not be less than 98%

The air leakage rate of the desulfurization system is ≤ 1%

5.1.3 Composition of Process System

The flue gas desulfurization device mainly includes the following systems:

1) Desulfurizer preparation system

2) Smoke system

3) SO2 absorption system

4) Desulfurization liquid circulation system

5) Desulfurization slag treatment system

5.1.4 Preparation system of desulfurizer

The desulfurizer for this project is lime.

The process of desulfurizer preparation system is as follows:

Bagged powdered lime powder is manually fed into the ash tank. After the lime is matured in the ash tank, it flows to the comprehensive circulation pool for desulfurization reaction.

1) Ash tank

The ash pond is a key equipment in the pulp making unit, dedicated to the humidification and maturation of lime.

The lime ash pond adopts a ground pond with a size of 1.5x1.5x1.5 meters and is equipped with a corrosion-resistant and wear-resistant mixer.