China's annual output of yellow phosphorus is about 1 million tons, accounting for more than 80% of the world's total output of yellow phosphorus. Yellow phosphorus tail gas is rich in more than 85% of CO, and it is a secondary energy with high economic value. Taking a yellow phosphorus plant with an annual output of 100,000 tons as an example, the annual output of yellow phosphorus tail gas is 2.7 × 108m3. It is assumed that 25% of it is used for raw material drying and the other can be used for power generation. The annual economic benefit can reach more than 100 million yuan.
Yellow phosphorus tail gas contains impurities such as sulfur, phosphorus, arsenic, and fluorine, which can be difficult to directly apply to industry. PH3 and elemental P4 are more difficult to remove, which will directly affect the further efficient use of yellow phosphorus tail gas. For example: the total power and total sulfur of the generator set are required to be less than 20mg / m3, otherwise PH3 and P4 will generate phosphoric acid during the combustion process, which will cause serious corrosion to the boiler and affect the stable operation of the boiler; used in high value-added chemical industry Product synthesis requires total phosphorus below 1 ppm, the lower the better. In short, the removal of phosphorus is the key to the efficient use of yellow phosphorus exhaust.
-Deficiencies in existing dephosphorization technologies-
Some domestic research institutions and institutions have successively developed some dephosphorization technologies for yellow phosphorus tail gas, but the results are not satisfactory. At present, there are two main dephosphorization technologies:
1. Temperature swing adsorption (TSA) + pressure swing adsorption (PSA)
The process route is complicated and the investment is high; the amount of adsorbent is large and the equipment covers a large area; desulfurization needs to be performed before dephosphorization, regeneration with inert gas or steam is required, the regeneration temperature is high (over 350 ° C), and the phosphorus content in the raw material gas The fluctuation affects the dephosphorization effect.
2. Discontinuous catalytic oxidation
Dephosphorization is an intermittent operation, which requires multiple towers to switch. The catalyst needs to be regenerated after adsorption saturation, which affects the life of the catalyst. Most of the sulfur is removed before the dephosphorization (the catalyst is not resistant to sulfur). The investment is large and the operation is complicated.
-Beijing Pioneer DePOx Dephosphorization Process Features-
Deep purification: The DePOx process can reduce the total phosphorus in the yellow phosphorus tail gas to less than 1 ppm.
Continuous dephosphorization: The DePOx process can continuously remove phosphorus from yellow phosphorus tail gas. The generated phosphorus oxides are taken out of the reactor with the reaction gas and do not accumulate on the catalyst. Therefore, there is no need to switch regeneration during the dephosphorization process.
Stable performance: DePOx dephosphorization catalyst has stable performance and can be used for a long time without replacement. The catalyst has a service life of more than 4 years.
Strong sulfur resistance: DePOx catalyst has good sulfur resistance, and sulfide does not affect the use of DePOx catalyst for dephosphorization.
Good adaptability: In a certain range, when the total phosphorus content fluctuates or the gas volume fluctuates, it does not affect the dephosphorization effect and service life.
Low cost: The number of DePOx process devices is small, the floor space is small, the one-time investment is low, and the long-term operating cost is low.
Simple operation: The device is easy to operate and easy to maintain.