1. Design conditions for waste sulfuric acid cracking furnace
Furnace raw materials: waste sulfuric acid 80~90,
Hydrocarbons 5-10, water 5-8
Furnace design temperature: 1200℃
Furnace design pressure: less than 6kPa
Cracking furnace fuel: natural gas or gas
2. Cracking furnace structure
1. Insulation lining
The insulation and wear-resistant lining material is a two-component refractory castables mixed with various aggregates, powders, curing agents, and additives according to a certain formula. It has the advantages of easy mechanization or manual application of furnace construction, short construction period, and low cost. The volume of lightweight insulation castables will expand or contract with changes in temperature. Therefore, when pouring a large area in the furnace, expansion joints must be left to prevent irregular cracks when the temperature changes. These irregular cracks will penetrate into the furnace shell, affecting the sealing of the furnace body, and will cause irregular displacement of the refractory lining, affecting the quality of the refractory lining, and in severe cases, causing the collapse of the cracking furnace lining structure. Generally, the expansion joint of the insulation lining is 5 mm wide and 70 mm thick at a distance of 1.5~2 m.
2. Refractory lining
The waste sulfuric acid cracking furnace should be very cautious when selecting refractory materials. Considering that waste sulfuric acid contains more impurities and even some solid particles, in order to prevent the waste sulfuric acid mist sprayed by the combined spray gun from corroding and wearing the refractory lining, the refractory lining of the front half of the furnace is made of composite phosphate corundum high-temperature refractory castables material. Corundum material has good corrosion resistance and wear resistance. Since most of the acid mist has been cracked into sulfur dioxide and water vapor in the second half of the furnace, the corrosion to the refractory lining is relatively small, so the refractory lining of the second half of the furnace can be made of relatively cheap high-aluminum cement heavy materials. According to the process requirements, the cracking furnace adopts a horizontal structure and a long furnace.
In order to ensure the lining quality of the furnace body at high temperature, the insulation lining is casted in the form of refractory castables, and the refractory lining must be prefabricated into wedge-shaped prefabricated blocks and transported to the site for masonry. The glue adopts the same acid-resistant adhesive as the parent material. After the masonry is completed, it is sintered at high temperature to make the refractory lining a whole.
