Calcium-based desulfurizing agent

Active, high surface area calcium hydroxide desulfurization (powder) technology performs 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, favorable for chimney exhaust diffusion, and less secondary pollution. It is suitable for flue gas desulfurization technology in industries such as steel, coking, cement, glass, and ceramics.

Section 1: 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, broad source of desulfurizing agents, and low difficulty in engineering implementation.

As the number of equipment increases, the drawbacks of this technology route begin to surface, 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. Authoritative statistics indicate that the coking industry alone produces up to 300,000 tons of sodium-based desulfurization ash annually. This figure is further multiplied 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 it to qualified institutions for disposal, with costs ranging from 300 to 500 yuan per ton, adding to the financial burden on businesses.

As of September 1, 2020, the revised "Environmental Protection Law of the People's Republic of China on Solid Waste Pollution" took 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 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. Through independently developed core equipment, we have created a new production process, achieving large-scale production. Our Tianjin production base has a 100,000-ton capacity, and the product performance is excellent!

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

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

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

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

V. High-activity, 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 rates. 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 active 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, highly active 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. Highly active calcium hydroxide has well-developed pores, which can quickly adsorb and absorb 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 surface area calcium hydroxide dry powder desulfurizer, directly喷射 into the flue gas duct by air conveying, rapidly dispersing into 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 in the flue gas, and then entering the bag filter with the flue gas. A small portion of the acidic media continues to react in the bag filter, and the烟气 after desulfurization is 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 aid flow air disks, and other accessories.

2. Feeding System: Utilizes a high-precision rotary feeder, measured through frequency conversion by 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 screen displaying main operating states or parameters such as material level, feeder operating frequency, etc. The system is equipped with high and low material level alarms, material level display, and Roto-Rooter fan operating status and fault alarms.

Section 8: Characteristics of High-activity, High-Surface Area Calcium Hydroxide Dry Desulfurization

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 40~300mg/Nm3, especially cost-effective.

2. Wide temperature range, utilizing flue gas treatment at 30-350°C, with high desulfurization efficiency.

3. The process is simple, with ultra-fine powder directly sprayed into the flue 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 new bag dust collectors.

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

6. Centralized control room operation without increasing staff, minimal footprint, ideal for low-temperature and low-sulfur environments.

7. Replacing the baking soda process with an alternative, investment-saving, low-energy consumption solution, and addressing solid waste issues.

Section 9: Typical Performance across Various Industries

   Coking Industry - Coke Pushing Ground StationShougang Qian'an Sinochem Coal Chemical Co., Ltd.'s No.1, No.2, and No.3 coke ovens - Push coke ground 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. 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 Specific Surface Area Calcium Hydroxide Desulfurization