Process Plant

Sulphur Storage and Melting Section

The solid sulphur is transported in bulk and stored in the storage house after receipt on site. Thereafter, the sulphur is sent to the melting section by belt conveyor where it is melted in the melting tank. The liquid sulphur clarifies by gravity in the clarifying tank to clean it up. The clean liquid sulphur is pumped to the sulphur burner. All tanks storing liquid sulphur are heated with steam coils and insulated to reduce heat losses.

Sulphur Burning and So2 Conversion Section

The refined clean liquid sulphur is pumped by a liquid sulphur pump to the sulphur spray gun installed in the front of the sulphur furnace. The sulphur is completely mixed with dry air and then burn itself out. The burner gas contains about 10% SO2 and 0.1-0.3% SO3. The gas is cooled down to 425 degrees Celsius through the first waste heat boiler to recover the gas heat and then enters the converter. The gas then goes through the second waste heat boiler from the first catalyst bed of the converter and is cooled down. Thereafter, the gas then goes into the second catalyst bed. The gas from the second bed of converter goes successively to hot IP exchanger where it heats the gas returning from inter-pass absorption tower, and then to third bed of the converter. After passing cold IP exchangers and SO3 cooler, the gas from the third bed goes into inter-pass absorption tower in which SO3 present in the gas is absorbed with circulating sulphuric acid. The gas from the fourth bed is cooled down to approximately 165 degrees Celsius through the third boiler and then enters final absorption tower in which SO3 is absorbed with circulating sulphuric acid and finally tail gas vents into atmosphere through a demister and stack. The total conversion efficiency is more than 99.8%.

Drying and Absorption Section

After being filtered by the air filter, air is pressurized by the air blower, then sent to the drying tower where the air undergoes the counter-current contact with sulphuric acid of 98% concentration and most of water in air is removed. The air is then sent through the Demister and SO3 cooler to the sulphur burner. The water content in the dried air is less than 0.1g/NM3. After the primary conversion in the converter, the gas goes into the bottom of the inter-pass absorption tower where it undergoes the counter-current contact with sulphuric of 98.05% concentration and SO3 is absorbed, after the gas is rid of the acid mist by the demister, it is returned to the conversion section to undergo the second conversion. After the secondary conversion, the gas comes to the bottom of the final absorption tower where it undergoes the counter-current contact with sulphuric acid of 98% concentration and SO3 is absorbed, the tail gas is rid of the acid mist by the demister, and then vented into the atmosphere via the stack.

Product Storage Section

The design concentration of product acid is 98% H2SO4. Product acid from drying and absorption section is metered by a flowmeter and then goes to the two storage tanks which have a 20 days production stock capacity. The product will then be loaded in tankers to be transported to clients.