Active, high 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, reduced equipment corrosion, no significant cooling of flue gas during purification, higher flue gas temperature after purification, facilitating chimney exhaust diffusion, and minimal secondary pollution. It is suitable for flue gas desulfurization technology in industries such as steel, coking, cement, glass, and ceramics.

Part 1: 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 high desulfurization efficiency, wide source of desulfurizing agents, and low difficulty in engineering implementation.

As the number of equipment increases, the drawbacks of this technological 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 falls under the category of 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 disposal, while others sell it to qualified institutions for processing, with costs varying from 300 to 500 yuan per ton, thereby increasing 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 breakthrough efforts by 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 and creating a new production process, we have achieved large-scale production. Our Tianjin production base boasts a 100,000-ton capacity, offering products with superior performance!

With our company's developed HNPS desulfurization system, over 30 units have been industrialized in use, demonstrating 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, steel heating furnaces, hot blast stoves, power plant boilers, and waste incineration industrial kilns.

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

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

Section 4: Reference Usage Conditions for High-activity, High-Surface Area Calcium Hydroxide

V. High Activity and High Specific Surface Area Calcium Hydroxide Characteristics

Highly active and high surface area calcium hydroxide boasts features such as porosity, high activity, good dispersibility, and high utilization. Its specific surface area is 3-4 times that of regular calcium hydroxide, and it is widely recognized as an excellent dry desulfurization product internationally. The practical dry desulfurization agents mainly include high 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, Europe, the U.S., and Japan had extensively used high surface area calcium hydroxide for desulfurization in waste-to-energy and thermal power plants, successfully replacing baking soda. High surface area calcium hydroxide features well-developed pores, which 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喷射 into the flue gas duct via air flow, rapidly dispersing in the flue gas under the action of an efficient jetting device, adsorbing and absorbing most of the acidic media such as F-, Cl-, SO2, and SO3 in the flue gas, and then entering the bag dust collector with the flue gas. A small portion of the acidic media continues to react in the bag dust collector, and 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: Large capacity powder storage silos, radar and anti-rotation level indicators, safety valves, vibration motors, arch-breaking assist flow air discs, and other accessories.

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

3. Power System: Positive pressure conveying by 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 running frequency. The system is equipped with high and low level alarms, material level display, and status and fault alarms for the Roots blower.

Section 8: High-activity, high-specific-surface-area calcium hydroxide dry desulfurization features

1. Meets ultra-low emission requirements with high desulfurization efficiency; SO2 outlet concentration can achieve zero emission standards. Flue gas SO2 concentration ranges between 40~300mg/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 an efficient jet to directly spray ultra-fine powder into the flue, completing the absorption reaction as the flue gas flows.

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 staff, with a small footprint, especially suitable for low-temperature, low-sulfur environments.

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

Section 9: Typical Performance across Various Industries

   Coking Industry - Coke Pushing Ground StationShougang Qian'an Sinopec Coal Chemical Co., Ltd. No. 1, 2, and 3 Coke Ovens - Coke Pushing Dust Removal with High-Activity, High-Surface-Area Calcium Hydroxide Desulfurization; industrial unit was put into operation on June 8, 2021, with stable emissions 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 Furnaces, Heating Furnaces - 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