High-activity calcium-based desulfurizing agent

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

1. Introduction to Desulfurization Technology

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

As the number of equipment increases, the drawbacks of this technical route begin to show, and how to handle desulfurization ash has become a new environmental protection challenge. Sodium-based desulfurization ash is a mixture of sodium sulfate, sodium sulfite, and sodium carbonate..The material has excellent water solubility and falls under the category of general solid waste that is difficult to dispose of in compliance. Authoritative statistics indicate that the coking industry alone produces up to 300,000 tons of sodium-based desulfurization ash annually. This figure is further increased by the power plants, hot blast stoves, and heating furnaces of 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 revised "Law of the People's Republic of China on the Prevention and Control of Environmental Pollution by Solid Wastes" came into effect, introducing new responsibilities for enterprises generating solid waste and imposing severe penalties on illegal activities. The pressure on businesses has surged!

Tianjin Huaneng Langtian Environmental Protection Equipment Co., Ltd. After four years of research and development efforts by our technical 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 and creating a new production process, we have achieved large-scale production. Our Tianjin production base boasts a 100,000-ton annual capacity, delivering superior product performance!

Utilizing the HNPS desulfurization package developed by our company, over 30 sets have been industrially applied with excellent operational data, low costs, and satisfied customers. Currently, the ultra-low emission desulfurization technology has been successfully applied in coking plant pusher ground stations, dry-cooling coke dust removal, coke oven flue gas, steelmaking furnace, hot blast furnace, power plant boilers, and waste incineration industrial furnaces.

High-activity, high-surface-area calcium hydroxide - microscopic crystal structure under electron microscopy

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

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

Section 5: High Activity, High Specific Surface Area Calcium Hydroxide Characteristics

Highly active and high surface area calcium hydroxide boasts characteristics of porous structure, high activity, good dispersibility, and high utilization. Its specific surface area is 3-4 times that of common calcium hydroxide, and is widely recognized as an excellent dry desulfurization product internationally. The practical dry desulfurization agents mainly include highly surface area calcium hydroxide and baking soda. While baking soda has a rapid reaction rate, it is relatively costly and difficult to dispose of solid waste. By the 1980s, highly surface area calcium hydroxide had been extensively used in waste-to-energy and thermal power plants in Europe, America, and Japan, successfully replacing baking soda. With well-developed pores, it can quickly adsorb and absorb HCl and SO2 in flue gas, achieving a utilization rate of over 85%.

Section 6: Introduction to HNPS Dry Desulfurization Process

Highly active, high surface area calcium hydroxide dry powder desulfurizer, directly jetted into the flue gas duct through air conveyance. Under the action of an efficient jetting device, the calcium hydroxide powder quickly disperses into the flue gas, adsorbs and absorbs most of the acidic media such as F-, Cl-, SO2, and SO3, and enters the bag filter with the flue gas. A small portion of the acidic media continues to react in the bag filter, and the flue gas after desulfurization is directly discharged through the induced draft fan.

This process is unaffected by smoke temperature fluctuations and can effectively react at room temperature and above.

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: Utilizes a high-precision rotating feeder, measured through frequency conversion with sensors.

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

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

Section 8: Characteristics of High-activity, High-specific-surface-area calcium hydroxide dry desulfurization

1. Meets ultra-low emission requirements with high desulfurization efficiency; the SO2 concentration in the outlet can reach zero-emission levels; flue gas SO2 concentration is 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, with ultra-fine powder directly sprayed into the flue gas duct through an efficient jet, completing the absorption reaction during the flow of flue gas.

4. Ensure the system meets ultra-low dust emission requirements with either the reuse or addition of a bag dust collector.

5. By-products are general solid waste, specifically saturated waste desulfurizing agent, with main components being CaSO4, Ca(OH)2, and CaCO3.

6. Centralized control room operation without increasing staff, small equipment footprint, especially suitable for low-temperature, low-sulfur environments.

7. Replacing the baking soda process with a substitute, it offers cost savings, low energy consumption, and addresses solid waste issues.

Section 9: Typical Performance across Various Industries

   Coking Industry - Pushing焦 Ground StationShougang Qian'an Sinochem Coal Chemical Co., Ltd.'s No.1, No.2, and No.3 coke ovens - Push coke surface dedusting with high-activity, high-surface-area calcium hydroxide desulfurization, the industrial unit was put into operation on June 8, 2021, with stable data below 10mg/m3.

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

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

4. Other Industries - Waste-to-Energy Power Plants & Power Station Boilers - High-Activity, High-Surface Area Calcium Hydroxide Desulfurization