Calcium-based desulfurizing agent

Active, high specific surface area calcium hydroxide desulfurization (powder) technology performs desulfurization absorption and product treatment in a dry state. This method offers advantages such as no waste acid or wastewater discharge, reduced equipment corrosion, no significant temperature drop in flue gas 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. 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, 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 source of desulfurizing agents, and low difficulty in engineering implementation.

As the quantity 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 falls under general solid waste that is difficult to dispose of in compliance with regulations. According to authoritative statistics, 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 warehouses for storage, while others sell the ash to qualified institutions for disposal, with costs ranging from 300 to 500 yuan per ton, adding to the financial burden on businesses.

The revised "Solid Waste Pollution Prevention and Control Law of the People's Republic of China" took effect on September 1, 2020, introducing new responsibilities for waste-producing enterprises and imposing severe penalties on illegal activities. The pressure on companies has surged!

Tianjin Huaneng Langtian Environmental Protection Equipment Co., Ltd. After four years of dedicated research and development efforts by our scientific staff, 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 capacity of 100,000 tons, offering superior product performance!

With our company's developed HNPS desulfurization package, over 30 units have been industrially applied, demonstrating good operational data, low costs, and satisfied customers. Currently, it has successfully been applied for ultra-low emission desulfurization in coking furnace pusher ground stations, dry-cooling coke plants, coke oven flue gases, 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

Section 4: High-activity, high-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. Baking soda has a fast reaction rate but is relatively expensive and difficult to dispose of solid waste. By the 1980s, highly 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. Highly specific surface area calcium hydroxide has well-developed pores, and it 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 is directly喷射 into the flue gas duct through air conveyance. Under the action of the high-efficiency jet, the calcium hydroxide powder rapidly disperses into the flue gas, 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 in the bag dust collector, and the flue gas after desulfurization is directly discharged through the induced draft fan.

This process is unaffected by smoke temperature variations; it 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 aid flow air disks, and other accessories.

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

3. Power System: Positive pressure conveying by Roots blower or compressed air, with 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 and feeder operation frequency. The system is equipped with high and low level alarms, material level indication, and status and fault alarms for the Roots blower.

Section 8: Characteristics of Dry Desulfurization with High-Activity and High-Surface-Area Calcium Hydroxide

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

2. Wide temperature window, utilizing flue gas treatment at 30-350℃ for high desulfurization efficiency.

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

4. Retrofit or add new bag dust collectors to ensure the system meets ultra-low dust emission requirements.

5. Byproduct is general solid waste, specifically saturated waste desulfurizing agent, mainly composed of CaSO4, Ca(OH)2, and CaCO3.

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

7. Replacing the baking soda process with an alternative, cost-effective investment, low energy consumption, and waste disposal solution.

Section 9: Typical Performance in Various Industries

   Coking Industry - coke pushing ground stationShougang Qian'an Sinochem Coal Chemical Co., Ltd. #1, #2, and #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 Specific Surface Area Calcium Hydroxide Desulfurization

3. Steel Industry - Hot Blast Furnaces, Heating Furnaces - High-activity, High Surface Area Calcium Hydroxide Desulfurization

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