The main raw material of sulphuric acid production is sulphur, coming from the unit of:
Melting and filtration unit (hereinafter referred to as MFU), the gondola cars sulphur unloading unit includes the following process facilities:
- elevated railway track for stripping cars;
Unit production capacity is 45÷80 tons of sulphur per hour.
Description of melting and filtration unit flowsheet and the process of unloading sulphur from gondola cars
Indoor storage is equipped, around the perimeter, with a retaining wall of reinforced concrete slabs up to 3 m high, an unloading platform with installation for simultaneous unloading of gondola cars, two bridge grab cranes for unloading, transfer and stacking of sulphur, a gantry loading system for mechanical sulphur unloading from gondola cars and hatches opening. Wall fencing helps to contain sulphur dust inside the storage and keeps sulphur free from precipitation and dust.
Solid (granulated, lump) sulphur is supplied in gondola cars. Set of gondola cars is moved to the sulphur storage unloading platform by diesel locomotive.
Bins with a conveyor system for transporting sulphur to smelters are placed along the edges of the storage. The loading of bins with sulphur is carried out with a grab crane, as well as truck loaders. Bins are equipped with stainless steel receiving grids made to trap pieces of sulphur larger than 100 mm.
Melting section is located adjacent to the lump sulphur storage. From the storage, solid (granulated, lump) sulphur is fed to the sulphur smelters through belt conveyor system. Sulphur smelters are cylindrical apparatuses with cone bottom with built-in stack heating elements (registers). Solid (granulated, lump) sulphur with ambient temperature is loaded into the smelters. The process of melting granulated sulphur occurs due to heat transfer through the wall of heating steam elements (registers) inside the smelters. In the center of the smelter there is a propeller agitator in guide cylinder.
After filtration, liquid sulphur corresponds to the parameters given in Table 1.
Table 1 - Comparative characteristics of the main parameters before and after filtration
Parameter |
Before filtration |
After filtration |
Mass fraction of ash, % not more than |
0,02 |
0,005 |
Mass fraction of base substances, % not more than |
0,06 |
0,03 |
Mass fraction of base substance, % not more than |
99,98 |
99,99 |