High surface area calcium hydroxide

The desulfurization technology of active, high-surface-area calcium hydroxide (powder form) carries out desulfurization absorption and product treatment under dry conditions. This method boasts advantages such as no wastewater or waste acid discharge, reduced equipment corrosion, no significant cooling of flue gas during purification, high flue gas temperature after purification, facilitating chimney exhaust diffusion, and minimal secondary pollution. It is suitable for flue gas desulfurization 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. 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 quantity 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 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 air furnaces, and heating furnaces of steel enterprises, as well as glass kilns, cement kilns, and others. Some companies rent land to build warehouses for storage, while others sell it to qualified institutions for disposal, with costs ranging from 300 to 500 yuan per ton, which adds to the companies' burden.

As of September 1, 2020, the new "Environmental Protection Law of the People's Republic of China on Solid Wastes" came into effect, introducing new responsibilities for enterprises generating solid waste and imposing severe penalties on violations. 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 surface area (BET) exceeding 45 m2/g. By independently developing core equipment, we have created a new production process and achieved large-scale production. Our Tianjin production base has a 100,000-ton capacity, offering products with superior performance!

With our company's developed HNPS desulfurization package, over 30 units have been industrially utilized with excellent operational data, low costs, and satisfied customers. Currently, it has successfully applied ultra-low emission desulfurization in coke oven pusher ground stations, dry-cooling coke dust removal, coke oven flue gas, steel heating furnaces, hot blast stoves, power plant boilers, and waste incineration industrial kilns.

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

Section 3: High Activity, High Specific Surface Area Calcium Hydroxide Desulfurization Agent Specifications

Section 4: Recommended Usage Conditions for Highly Active, High Specific Surface Area Calcium Hydroxide

V. High activity and high specific surface area calcium hydroxide properties

Highly active and high 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 ordinary calcium hydroxide and is recognized internationally as an excellent dry desulfurization product. Dry desulfurization agents in practice 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, high 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. High surface area calcium hydroxide has well-developed pores, enabling rapid adsorption and absorption of HCl and SO2 from flue gas, achieving a utilization rate of over 85%.

Section 6: Introduction to HNPS Dry Desulfurization Process

Highly active and high specific surface area calcium hydroxide dry powder desulfurizer, directly喷射 into the flue gas duct by air conveying, where the calcium hydroxide powder rapidly disperses in the flue gas under the action of an efficient jet, adsorbing and absorbing most of the acidic media such as F-, Cl-, SO2, and SO3. The flue gas, after desulfurization, enters the bag dust collector, where a small portion of the acidic media continues to react. The烟气is then 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-specific-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 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 blowers or compressed air, one in operation and one in reserve.

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

Section 8: Characteristics of Dry Desulfurization with High Active and High Specific 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 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 the ultra-fine powder directly sprayed into the flue gas channel through an efficient jet, completing the absorption reaction during the flow of the flue gas.

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

5. By-products are general solid waste, consisting of saturated waste desulfurizing agent, mainly containing CaSO4, Ca(OH)2, and CaCO3.

6. Centralized control room operation without increasing staff, with minimal equipment footprint, especially suitable for low-temperature and 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 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. 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 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