Calcium Hydroxide Desulfurization Agent

Active, high specific surface area calcium hydroxide desulfurization (powder) technology performs desulfurization absorption and product treatment under dry conditions. 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 post-purification, favorable for chimney exhaust diffusion, and minimal secondary pollution. It is suitable for desulfurization technology in flue gas of 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. The technology is mature and operates stably. The SDS desulfurization process route using sodium bicarbonate as the alkaline source has rapidly expanded its market share due to its advantages such as high desulfurization efficiency, widespread availability of desulfurization agents, and low difficulty in project implementation.

As the number of equipment increases, the drawbacks of this technical 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 the category of 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 power plants, hot air furnaces, 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 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 dedicated research and development, with the efforts of our scientific and technical staff, we have successfully developed high surface area calcium hydroxide with a surface area (BET) exceeding 45 m2/g. Through independently developed core equipment, we have created a new production process, achieving large-scale production. Our Tianjin production base boasts a 100,000-ton capacity, delivering exceptional product performance!

With our company's developed HNPS desulfurization package, it has been industrially used in over 30 units 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 furnaces.

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

Four: High-activity, high-specific surface calcium hydroxide, recommended usage conditions

Section 5: High-activity, High-Surface-Area Calcium Hydroxide Properties

Highly active and high specific surface area calcium hydroxide features porous structure, high activity, good dispersibility, and high utilization rate. Its specific surface area is 3-4 times that of common calcium hydroxide, and it is recognized as an excellent dry desulfurization product internationally. Dry desulfurization agents used in practice are primarily high 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, high specific surface area calcium hydroxide had been widely used in waste-to-energy power plants and thermal power plants in Europe, America, and Japan, successfully replacing baking soda. High specific surface area calcium hydroxide has well-developed pores, and 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 conveying. Under the action of the high-efficiency jetting unit, the calcium hydroxide powder quickly 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 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 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 assist flow air disks, and other accessories.

2. Feeding System: Equipped with a high-precision rotating feeder, metered through frequency conversion by sensors.

3. Power System: Positive pressure conveying by Roots blower or compressed air, one in operation and one in reserve.

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

Section 8: Characteristics of Dry Desulfurization with High-activity and High-Surface-areas 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 window, utilizing flue gas treatment at 30-350℃ with high desulfurization efficiency.

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

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

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

6. Centralized control room operation without increasing personnel, with minimal floor space required, especially suitable for low-temperature, low-sulfur environments.

7. Alternative to baking soda process, cost-effective investment, low energy consumption, and waste solid solution.

Section 9: Typical Performance in Various Industries

   1. Coking Industry - Pushing Coal Yard StationShougang Qian'an Sinochem Coal Chemical Co., Ltd. #1, #2, and #3 coke ovens - Push coke ground dedusting with high-activity, high-specific 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 - 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-surface-area Calcium Hydroxide Desulfurization

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