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, low equipment corrosion, no significant cooling of flue gas during purification, high flue gas temperature after purification, favorable for 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.

I. 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 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 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 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 disposal, while others sell it to qualified institutions for processing, with costs ranging from 300 to 500 yuan per ton, thereby increasing the burden on businesses.

The revised "Law of the People's Republic of China on the Prevention and Control of Environmental Pollution by Solid Wastes" took effect on September 1, 2020, 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, with the efforts of our technical staff, we have successfully developed high surface area calcium hydroxide with a specific surface area (BET) exceeding 45 m2/g. Through independently developed core equipment, we have created a new production process and achieved mass production. Our Tianjin production base has a 100,000-ton capacity, and our products boast excellent performance!

With our company's developed HNPS desulfurization package, over 30 units have been industrially applied with excellent operational data, low costs, and satisfied customers. Currently, it has successfully been 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 - microscopic crystal structure under electron microscopy

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

Highly active, high surface area calcium hydroxide boasts features such as porosity, high activity, good dispersion, and high utilization. Its specific surface area is 3-4 times that of regular calcium hydroxide and is recognized internationally as an excellent dry desulfurization product. The practical dry desulfurization agents primarily 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, high surface area calcium hydroxide had been widely used in waste-to-energy and thermal power plants in Europe, America, and Japan, successfully replacing baking soda. High 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 desulfurizer, directly jetted into the flue gas duct via air conveying, rapidly 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, and is then carried into 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: Characteristics of High-activity, High-specific-surface-area Calcium Hydroxide Desulfurization System

1. Storage System: Equipped with large-capacity powder storage silos, radar and anti-rotation level indicators, safety valves, vibration motors, arch-breaking auxiliary 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 by Roots blower or compressed air, one in use and one in reserve.

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 includes high and low 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 requirements with high desulfurization efficiency; export SO2 concentration can reach near-zero emission standards. Flue gas SO2 concentration ranges between 40~300mg/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 by an efficient jet, completing the absorption reaction during the flow of flue gas.

4. Ensure low dust emissions in the system by either upgrading or adding a bag dust collector.

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

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

Section 9: Typical Performance in Various Industries

   Coking Industry - Coke Pushing Ground StationShougang Qian'an Sinopec Coal Chemical Co., Ltd. 1st, 2nd, and 3rd coke ovens - Push coke surface dust removal 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 - Coke Oven Gas and Flue Gas - High Activity, High Specific 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