News & Media
2024/11/14
391
Currently, sodium silicate (also known as water glass) production in China relies primarily on 2 methods:
1. Solid-phase Method: uses soda ash and quartz sand as raw materials, which are melted at high temperatures in a kiln to produce solid sodium silicate.
2. Liquid-phase Method: uses caustic soda and quartz sand as raw materials, which react under high heat and pressure in a reactor to produce liquid sodium silicate. However, the liquid-phase method cannot produce high-modulus sodium silicate, making the solid-phase method the predominant process.
In China, solid-phase sodium silicate production mainly uses heat storage type full-gas horseshoe flame tank furnaces. In 2020, the successful commissioning of China’s first 80m² oxy-fuel kiln by a Shandong-based company, producing 200 tons per day of sodium silicate marks a shift toward a new model where natural gas is utilized as fuel and oxygen-enriched combustion is incorporated.
Traditional horseshoe-flame tank furnaces primarily use coal gas or natural gas as fuel. In these systems, combustion in these furnaces is facilitated by oxygen from the air blown into the furnace. However, air contains only 20.95% oxygen, with the majority being nitrogen, which does not aid combustion. When only air is used, furnace design must account for the space needed for N2 expansion during combustion. Additionally, nitrogen carries away substantial heat energy through the exhaust, increasing the volume of flue gases and resulting in more NOx pollutants. Furthermore, due to global energy shortages, rising petrochemical fuel prices, and increasingly stringent environmental policies, sodium silicate production processes require continuous improvement. Oxygen-enriched melting technology, which replaces air with oxygen, effectively addresses these challenges.
Oxygen-enriched melting helps increase the inner furnace temperature, enhance equipment processing capacity, reduce energy consumption, and decrease flue gas emissions. Economically, using oxygen-enriched melting increases production capacity by about 30% for furnaces of the same scale size. Melting energy consumption is reduced, with natural gas consumption per ton of sodium silicate dropping by around 30%. Additionally, the power consumption required for exhaust treatment decreases. The total economic benefits from these savings—after deducting the construction, operational, and maintenance costs of the oxygen generation equipment—are substantial. Based on current operational data, the economic benefits are highly favorable. Therefore, compared to traditional air-blown methods, oxygen-enriched melting provides higher melting intensity, lower fuel consumption, and improved environmental impact, showing substantial potential for widespread use in the sodium silicate production.
Compared to traditional cryogenic air separation, VPSA (Vacuum Pressure Swing Adsorption) oxygen generation has many advantages such as simpler process, higher safety, lower investment and power consumption, reduced operational expenses, and higher automation. Its limitations lie in the lack of by-products (N2 and Ar), and lower purity levels (≤95%). In sodium silicate production, N2 and Ar are not typically required in the reaction, and 24%~90% enriched oxygen is generally needed, aligning well with VPSA's capabilities. For instance, the company in Shandong uses fully oxy-fuel kilns to produce approximately 73,000 tons of sodium silicate annually. In 2020, It installed a VPSA oxygen generation unit (2,200Nm³/h, 93%) designed by PKU Pioneer. The oxygen plant features a short construction period, small footprint, and low investment cost and has been operating smoothly.
In summary, VPSA oxygen generation technology aligns closely with the oxygen requirements of oxy-fuel kilns used in the sodium silicate industry. Utilizing VPSA technology to achieve oxygen-enriched combustion instead of ambient air for combustion allows solid-phase sodium silicate manufacturers to significantly improve production efficiency and create substantial economic benefits.
With 25 years of rich experience in VPSA/PSA oxygen generation, PKU Pioneer has also achieved remarkable success in the oxygen-enriched combustion for industries such as steel, non-ferrous metallurgy, cement, waste incineration, lithium battery, etc. We’ve provided professional and advanced oxygen plant solutions to nearly 150 large steel and metallurgical enterprises both domestically and internationally, helping clients achieve multiple goals including output expansion, cost control, and environmental protection. To date, PKU Pioneer has supplied over 300 efficient and reliable VPSA/PSA oxygen generation units across more than 20 industrial sectors as the world’s largest oxygen equipment supplier, with a presence in regions including Asia, Europe, South America, Africa, etc.
