Dry Desulfurization

Active, high specific surface area calcium hydroxide desulfurization (powder) technology performs desulfurization absorption and product treatment in a dry state. This method offers advantages such as no wastewater or waste acid discharge, reduced equipment corrosion, no significant cooling of flue gas during purification, higher flue gas temperature after purification, favorable for chimney exhaust diffusion, and less secondary pollution. It is suitable for desulfurization technology in flue gas for industries such as iron and steel, coking, cement, glass, and ceramics.

Section 1: Flue Gas Desulfurization Technology Introduction

In recent years, the dry desulfurization technology for flue gas has seen increasing application in small and medium-sized flue gas desulfurization systems, with mature technology and stable operation. Among them, the SDS desulfurization process route using sodium bicarbonate as the alkali source has rapidly expanded its market share due to its advantages such as high desulfurization efficiency, wide source of desulfurizing agents, and low difficulty in project implementation.

As the number of equipment increases, the drawbacks of this technology route begin to surface, and how to deal with desulfurization ash becomes a new environmental protection challenge. Sodium-based desulfurization ash is a mixture of sodium sulfate, sodium sulfite, and sodium carbonate..The substance has excellent water solubility and falls under general solid waste that is difficult to dispose of in compliance with regulations. Authoritative statistics show that the coking industry alone produces up to 300,000 tons of sodium-based desulfurization ash annually. This figure is further increased by power plants, hot blast stoves, and heating furnaces in steel enterprises, as well as glass and cement kilns. Some companies rent land to build storage warehouses for storage, while others sell it to qualified institutions for disposal, with costs ranging from 300 to 500 yuan per ton, adding to the burden on businesses.

As of September 1, 2020, the new version of the "Environmental Protection Law of the People's Republic of China against Solid Waste Pollution" took effect, which introduces related responsibilities for enterprises generating solid waste and clearly stipulates severe penalties for illegal acts. The pressure on enterprises has surged!

Tianjin Huaneng Langtian Environmental Protection Equipment Co., Ltd. After four years of dedication, with the efforts of our R&D team, we have successfully developed high-surface-area calcium hydroxide with a specific surface area (BET) exceeding 45 m2/g. By independently developing core equipment, we have created a new production process, achieving mass production. Our Tianjin production base boasts a 100,000-ton capacity, with exceptional product performance!

With the HNPS desulfurization system developed by our company, over 30 units have been industrially applied with good operational data, low costs, and satisfied customers. Currently, the system has been successfully applied for ultra-low emission desulfurization in coke oven pusher ground stations, dry-cooling coke plants, coke oven flue gases, steelmaking heating furnaces, hot blast stoves, power plant boilers, and waste incineration industrial kilns.

High-activity, high-specific-surface-area calcium hydroxide - Microcrystalline structure under electron microscopy

Section 3: High-activity, high-specific-surface-area calcium hydroxide desulfurization agent specifications

Section 4: High-activity, high-specific-surface-area calcium hydroxide - recommended usage conditions

V. High-activity, high-specific-surface-area calcium hydroxide characteristics

Highly active, high specific surface area calcium hydroxide features porosity, high activity, good dispersion, and high utilization. Its specific surface area is 3-4 times that of common calcium hydroxide, and it is widely recognized as an excellent dry desulfurization product internationally. Dry desulfurization agents used in practice are primarily high specific surface area calcium hydroxide and baking soda. Baking soda has a fast reaction rate but is relatively expensive and difficult to dispose of as solid waste. By the 1980s, high specific surface area calcium hydroxide had been extensively used in desulfurization in waste-to-energy and thermal power plants in Europe, America, and Japan, successfully replacing baking soda. High specific surface area calcium hydroxide has well-developed pores, enabling it to rapidly adsorb and absorb HCl and SO2 from flue gas, achieving a utilization rate of over 85%.

Section 6: Introduction to HNPS Dry Desulfurization Process

Highly active and high surface area calcium hydroxide dry powder desulfurizer, directly喷射 into the flue gas duct via air conveying. Under the action of the high-efficiency jetting unit, the calcium hydroxide powder rapidly disperses into the flue gas, adsorbing and absorbing most of the acidic media such as F-, Cl-, SO2, and SO3. It then enters the bag dust collector with the flue gas, where a small portion of the acidic media continues to react. The烟气, after desulfurization, is directly discharged through the induced draft fan.

This process is unaffected by the temperature of the smoke, and can effectively react above room temperature.

Section 7: Features of High-activity, High-Surface-Area Calcium Hydroxide Desulfurization System

1. Storage System: Equipped with large-capacity powder storage silos, radar and anti-rotation level sensors, safety valves, vibration motors, arch-breaking assist flow air discs, and other accessories.

2. Feeding System: Equipped with a high-precision rotating feeder, measured by frequency conversion through sensors.

3. Power System: Positive pressure conveying with Roots blower or compressed air, one in operation and one in standby.

4. Control System: Centralized control in the control room, with computer screens displaying material level, feeder operating frequency, and other key operating states or parameters. The system is equipped with high and low level alarms, material level display, status of the Roots blower, and fault alarms.

Section 8: Characteristics of High-activity, High-Surface-Area Calcium Hydroxide Dry Desulfurization

1. Meets ultra-low emission requirements with high desulfurization efficiency; export SO2 concentration can reach near-zero emission standards; flue gas SO2 concentration between 40~300 mg/Nm3, particularly cost-effective.

2. Wide temperature range, utilizing flue gas treatment at 30-350°C, with high desulfurization efficiency.

3. The process is simple, utilizing a high-efficiency jet to directly spray ultra-fine powder into the flue, where absorption and reaction are completed during the flow of flue gas.

4. Ensure low dust emissions for the system, either by utilizing existing bag dust collectors or adding new ones.

5. By-products are general solid waste, specifically saturated waste desulfurizing agents, primarily composed of CaSO4, Ca(OH)2, and CaCO3.

6. Centralized control room operation, no additional staff required, compact equipment footprint, especially suitable for low-temperature, low-sulfur environments.

7. Substitutes the Baking Soda Process in SDS, offering cost savings and low energy consumption, while solving solid waste issues.

Section 9: Typical Performance in Various Industries

   Coking Industry - Pushing焦 StationShougang Qian'an Sinopec Coal Chemical Co., Ltd.焦炉1#, 2#, and 3# push coking surface dedusting - high-activity, high-surface-area calcium hydroxide desulfurization. The industrial facility was put into operation on June 8, 2021, with stable data below 10 mg/m³.

2. Coke Industry - Dry Quenching Gas and Coke Oven Flue Gas - High-activity, High-Surface Area Calcium Hydroxide Desulfurization

3. Iron and Steel Industry - Hot Blast Furnaces, Heating Furnaces - High Activity, High Specific Surface Area Calcium Hydroxide Desulfurization

4. Waste-to-Energy & Power Plant Boilers - High-Activity, High-Surface-Area Calcium Hydroxide Desulfurization