Active, high-specific-surface-area calcium hydroxide desulfurization (powder) technology carries out desulfurization absorption and product treatment in a dry state. This method offers advantages such as no wastewater or waste acid discharge, less equipment corrosion, no significant cooling of flue gas during purification, higher flue gas temperature post-purification, beneficial 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. Desulfurization Technology Introduction

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 mature technology and stable operation. Among these, the SDS desulfurization process 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.

With the increase in the number of installations, the drawbacks of this technology route begin to show, and how to deal with desulfurization ash has become a new environmental 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 general solid waste that is difficult to dispose of in compliance with regulations. 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, thereby increasing the burden on businesses.

As of September 1, 2020, the revised "Solid Waste Pollution Control Law of the People's Republic of China" came into effect, introducing new responsibilities for waste-producing enterprises and explicitly imposing severe penalties on illegal activities. The pressure on companies 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 calcium hydroxide with a high specific surface area, achieving a specific surface area (BET) of over 45 m2/g. By independently developing our core equipment, we have created a new production process, enabling large-scale production. Our Tianjin production base boasts a 100,000-ton capacity, with excellent product performance!

Utilizing the HNPS desulfurization complete set developed by our company, it has been industrially applied in over 30 sets of equipment, with favorable operational data, low costs, and satisfied customers. Currently, it has successfully been applied in industrial furnaces such as coke oven pusher ground stations, dry quenching dust removal, coke oven flue gas, steel heating furnaces, hot blast stoves, power plant boilers, and waste incineration, achieving ultra-low emissions desulfurization.

High-activity, high-surface-area calcium hydroxide - Microcrystalline 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

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

Highly active and high specific surface area calcium hydroxide boasts characteristics such as porosity, high activity, good dispersibility, and high utilization rate. Its specific surface area is 3-4 times that of ordinary calcium hydroxide and is widely recognized as an excellent dry desulfurization product internationally. The practical dry desulfurization agents mainly include highly specific surface area calcium hydroxide and baking soda. While baking soda has a fast reaction rate, it is relatively expensive and difficult to dispose of solid waste. By the 1980s, high-specific surface area calcium hydroxide had been widely used in waste-to-energy and thermal power plants for desulfurization in Europe, America, and Japan, successfully replacing baking soda. The highly specific surface area calcium hydroxide has well-developed pores, allowing for rapid adsorption and absorption reactions of 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 desulfurizing agent, directly jetted into the flue gas duct via air flow, quickly disperses in the flue gas under the action of an efficient jetting device, adsorbs and absorbs most of the acidic media such as F-, Cl-, SO2, and SO3 in the flue gas, and then enters the bag dust collector with the flue gas. A small portion of the acidic media continues to react within the bag dust collector. The烟气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: Characteristics 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 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 main operating states or parameters such as material level and feeder operation frequency. 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 Dry Desulfurization with High-activity, High-Surface-Area Calcium Hydroxide

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

2. Wide temperature range, with flue gas treatment at 30-350°C, achieving 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 low dust emissions in the system with either the reuse or addition of bag dust collectors.

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

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

7. Replacing the baking soda process with a more cost-effective and energy-efficient alternative, addressing solid waste concerns.

Section 9: Typical Performance Across Industries

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

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

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

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