The heat reaction furnace is the core equipment in the sulfur recovery unit, and the acid gas burner is the key to the core. The fuel gas, acidic gas, and combustion air are mixed by the burner in a definite form and then sprayed into the fire channel and furnace to produce a combustion reaction. The high-performance burner can improve the conversion rate of elemental sulfur in the thermal reactor, eliminate the influence on the downstream equipment from heavy hydrocarbon of ammonium salt or other impurities, and ensure the high-efficiency and long-cycle operation of the equipment.
Common burner types include acid gas reaction furnace burner, acid gases directly incinerated burner, online heat furnace burner, and tail gas incinerator burner.
Program for ignition control
- Start-up → open the electromagnetism valve to purge the hearth (start time can be set)
- The igniter begins to strike a light (the duration of continuous ignition is less than 60s).
- Start the fuel gas solenoid valve and fuel gas is supplied when turning on the burner.
- After ignition, delay the 20s to start the flame monitor.
Notice:
- If there is no flame signal detected. The fuel gas valve must be shut off immediately. The ignition program goes back to its original status. Give an alarm at the same time (a circle program can be set for this operation).
- If the flame signal was detected. Stabilize the flame for a period of time, open the main fuel valve and show successful Ignition.
Burning mode
At present, domestic and foreign acidic gas burners of sulfur recovery units all adopt high-strength fluidic distribution, and the mixed type of fuel and air is divided into two types: premixed type and diffused type.
The former type has the advantages of sufficient mixing, and high burning speed, however, the requirement of design and manufacture is relatively high, operating flexibility is low, easy to blow off or temper.
The latter has high operating flexibility, it is not easy to blow off or temper, but it has a long mixing time, low intensity of combustion, and slow speed.
From the perspective of the current application, the premixed type takes a large proportion. As long as the design is reasonable and appropriate, the reaction degree of the premixed type is deep and the effect of ammonia burning is also obvious.
Key points of burning design
The structure design and the process parameters of the acid gas burner are closely connected with the heated reactor.
According to the composition of acidic gas, the number of impurities, allowable pressure drop, medium temperature, operating flexibility, and other conditions to make a reasonable structure design are the most basic requirements for the designer of the acidic gas burner.
Some manufacturers use software to carry out CFD numerical simulation of the designed burner and reactor to verify the rationality and reliability of the design.
Through the numerical simulation, we can get the data of media in the burner or the heated reactor, including speed, temperature, pressure, concentration distribution, as well as quantities that change with time.
Determine the whirlpool distribution characteristics, oxidation characteristics, defluent area, etc., and calculate other related physical quantities, such as pressure loss and efficiency. In addition, combined with CAD, it can also be used to optimize the structural design of the burner and reactor.
