Furnace & Fired Heater Optimization

Yokogawa Europe Solutions, one of the global market leaders in process automation, instrumentation & industrial information systems. Duiker Combustion Engineers active in development, design, supply and servicing of combustion and process equipment & technology.

The combination of Duiker’s knowledge & expertise with that of Yokogawa leads to safe operation with minimal air excess for increased efficiency. This leads to substantial and achievable fuel savings and therefore CO₂ reduction. The safety of a furnace is hereby at least kept at the same level, but in many cases even improved. Duiker Combustion Engineers ensures that a furnace operates optimal from a combustion and mechanical perspective.

• Accurate & stable measurement of oxygen and unburned hydrocarbons using laser technology.
• Reduction of oxygen content to a safe minimum using advanced process control.
• Ensure burners combust fuel in an optimal way.
• Ensure that the furnace is gas tight, so that no air is accidentally flowing in from the outside.
• Eliminate fear of burner failures and as a remedy sending more air to the burners, resulting in less efficient cookers and more CO₂ emissions.

• Industrial heater/furnaces that combust fossil fuels for their energy input

Implementation of CombustionONE on a Steam Methane Reformer

The baseline or initial operation of the heater is as follows: the type of heater is an induced draft heater which is working on an average of 2,2% oxygen level. We only have an indicative value of the oxygen level as it is measured with a zirconia probe. Production of this heater is almost 64 thousand kilograms per hour with fuel consumption of more than 8 thousand normal cubic meters per hours. Fuel is a mixture of high methane natural gas, local low quality methane gas, and some tail gases. Heater is very volatile and works constantly in manual mode due to regular changes in fuel quality and ambient conditions. This is visible when you look at the coil outlet temperature volatility: plus minus 7 ^oC.

Baseline conditions:

• Oxigen level: 2,2%
• Throughput: 63 820 kg/h
• Fuel consumption: 8 167 Nm3/h
• Coil outlet temperature: +- 7 ^oC

Potential benefits of the implementation of new technologies

Due to old design worst scenario is assumed, but complete elimination of tramp air will not be possible, even by decreasing arch draft to the minimum, so for business cases purposes we assume an oxygen level of 1,2 %. Decreasing oxygen level by 1% will provide almost 290 normal cubic meters per hours of fuel savings, crossover temperature will decrease by 9 ^oC, CO₂ production will decrease by 3 600 tons per annum. Of course, by decreasing flue gas temperature, we will decrease production of the steam by 4 GJ/h. Lower pre-heating of the feed is included in fuel savings calculation, as we need to fire a little bit more to heat up product from lower inlet temperature.

• Decrease oxygen level to: 1,2%
• Fuel savings: 286 Nm3/h (natural gas)
• Crossover temperature: decrease by 9 ^oC
• CO2 emission: decrease by 3 600 t/annum
• Negative impact on steam: – 4 GJ/h
• Coil outlet temperature: +- 0,5 ^oC

With an average price for natural gas 7,5 EUR for GJ and actual CO₂ certificate pricing around 27 EUR per tonne we get annual savings around 520 thousand euro per year. Return of Investment in this case is around 1 year.

Above example has been executed by Yokogawa only without Duiker. At this moment Duiker and Yokogawa did not execute a joint business case, because the cooperation between Yokogawa and Duiker only just started.

This figure has been based upon a heater/furnace that operates currently on 5% oxygen in the flue gasses. The curve visualises the potential fuel savings once the heater start operation at a lower oxygen percentage. A potential fuel saving is possible of about 6,5% in case this heater changes it operation from 5 to 3% oxygen in the flue gasses. These potential percentages of fuel savings are equal to the potential percentages of CO₂ reduction.

• Reduction of fuel consumption furnace/heater

• Enhanced safety and process stability

• MOL refinery