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 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 flue gas desulfurization technology in industries such as steel, coking, cement, glass, and ceramics.

I. 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, thanks to its mature technology and stable operation. Among these, 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 engineering 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 challenge. Sodium-based desulfurization ash is a mixture of sodium sulfate, sodium sulfite, and sodium carbonate..The substance has excellent water solubility and is classified as 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 air furnaces, 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 revised "Environmental Protection Law of the People's Republic of China on Solid Waste Pollution" 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 staff, 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 mass production. Our Tianjin production base boasts a 100,000-ton capacity, delivering superior product performance!

Utilizing the HNPS desulfurization package developed by our company, over 30 sets have been industrialized and are performing well with low costs and satisfied customers. Currently, the ultra-low emission desulfurization technology has been successfully applied in coking plant push-aside ground stations, dry-cooling coke dust removal, coke oven flue gas, steelmaking heating furnaces, hot blast stoves, power plant boilers, and waste incineration industrial kilns.

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

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

Four. Reference usage conditions for high-activity, high-specific surface area calcium hydroxide

Five: High activity and high specific surface calcium hydroxide properties

Highly active and high specific surface area calcium hydroxide features porous structure, high activity, good dispersion, and high utilization rate. Its specific surface area is 3-4 times that of common calcium hydroxide and is widely recognized as an excellent dry desulfurization product internationally. In practice, the main dry desulfurization agents are high specific surface area calcium hydroxide and baking soda. While baking soda has a faster reaction rate, it is relatively costly and difficult to handle solid waste. In the 1980s, high specific surface area calcium hydroxide had been extensively used in waste-to-energy power plants and thermal power plants for desulfurization in Europe, America, and Japan, successfully replacing baking soda. High specific surface area calcium hydroxide possesses well-developed pores, which allows for quick adsorption and absorption reactions with HCl and SO2 in 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 desulfurizing agent, directly jetted into the flue gas duct by air conveying, quickly disperses in the flue gas under the action of the high-efficiency jetting device. It adsorbs and absorbs most of the acidic media such as F-, Cl-, SO2, and SO3 in the flue gas, 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 by 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 auxiliary flow air discs, and other accessories.

2. Feeding System: Utilizes a high-precision rotating feeder, with frequency conversion measurement via sensors.

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

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

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

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

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

3. The process is simple, directly injecting the ultra-fine powder into the flue with an efficient jet, where absorption reaction is completed during the flow of flue gas.

4. Ensure low dust emissions in the system by either upgrading or adding new bag dust collectors.

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

6. Centralized control room operation without increasing staff, with minimal equipment footprint, particularly suitable for low-temperature, low-sulfur environments.

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

Section 9: Typical Performance in Various Industries

   Coking Industry - Pushing Coke Surface StationShougang Qian'an Sinochem Coal Chemical Co., Ltd. #1, #2, and #3 coke ovens - Push coke ground 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 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 Surface Area Calcium Hydroxide Desulfurization

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