Burners For Sulfur Recovery Unit

Burners For Sulfur Recovery Unit

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

  1. Start-up→Open the electromagnetism valve to purge the hearth(start time can be set)
  2. Igniter begins to strike a light (duration of continuous ignition is less than 60s).
  3. Start the fuel gas solenoid valve and fuel gas is supplied when turning on the burner.
  4. After ignition, delay the 20s to start the flame monitor.
  • If there is no flame signal was detected. The fuel gas solenoid valve must be shut off immediately. The ignition program goes back to the original status. Give an alarm at the same time (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.

Ignition program must be absolutely credibility. Generally, there are two units of the flame detector. If one of them detects no flame, it will give an alarm. If both of them detect that there is no flame, the fuel gas supply must be cut off. In view of its importance, the Ignition program must be careful to be selected. Before the acid gas supplied, the fuel gas must be primarily supplied to warm furnace up. While the furnace temperature up to the needed, cut off the fuel and give away of the acid gas. The spontaneous combustion of acid gas reaches its own thermal equilibrium, releases ultraviolet rays, its intensity and frequency are different from those released from the burning of ordinary fuel. The general ultraviolet flame monitor can detect the ultraviolet rays released by the fuel gas and the acid gas combustion flame. The general ultraviolet radiation detector can only detect the ultraviolet radiation while acid gas and fuel are both supplied in burning. However, when the acid gas enters into the burner, the monitor will simply judge according to the change of the intensity of the ultraviolet light. It is easy to have misinformation, for example, sometimes the monitor has abnormal indication but the flame is actually normal, which has appeared many times in practical applications. False alarms cause great trouble for the operation of the device. Ultraviolet flame monitors produced by some well-known foreign companies are equipped with microprocessors, which can accurately detect different types of flame under different combustion conditions and intelligently judge. It is very suitable for the flame detection of acid gas furnace burner.

Burning mode

At present, domestic and foreign acidic gas burners of sulfur recovery unit 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, high burning speed, however, the requirement of design and manufacture are 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 long mixing time, low intensity of combustion, 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 point of design

The structure design and the process parameters of the acid gas burner are closely connected with the heat 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. Sometimes, the manufacturer’s user performance will also provide a certain experience reference to the designer. At present, some famous enterprises in the industry can also 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 (H2S) S02) NHa, 02, etc.) in the burner or the heat reactor, including speed, temperature, pressure, concentration distribution, as well as quantities which changes 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.