Clean fossil fuel heat and power plants - Nebb process solutions

---

Combined hydrogen and power production with 100 % CO₂ capture

Nebb has developed (patent pending) an energy efficient method for combined hydrogen- and oxyfuel power production.

The largest sources for CO₂ emissions come from fossil fuel fired power production and from the transport sector. To reduce a major part of emissions, CO₂ can be captured from thermal power plants in parallel with production of hydrogen, and hydrogen can be an energy carrier within the transport sector.

The main reasons to consider hydrogen as an energy carrier compared to carbon containing fuel is that the resources of fossil fuels are limited and because there are environmental problems related to CO₂ emissions from carbon contained fuels.

Hydrogen can be produced industrially by water electrolysis or by hydrocarbon reforming (coal gasification). Hydrogen production from hydrocarbon reforming contributes to CO₂ emissions if the by-product, CO₂, is not captured and stored in a suitable underground structure.

Process solution

Figure 1 shows the Nebb process solution that integrates an oxyfuel power process with hydrogen production from water electrolysis. The oxyfuel process can supply electric power and water to the water electrolysis and the water electrolysis supply oxygen to the oxyfuel power process. The innovative of this invention is the integration of the water electrolysis and the oxyfuel power process.

Figure 1: Combined hydrogen and power production with 100 % CO₂ capture.

The advantages of the integrated process solution are:

1. Power and hydrogen production with 100 % CO₂-capture
2. The oxygen produced in the water electrolysis increases the efficiency of the power production process due to reduced oxygen energy requirement and operating costs in the power process.
3. Flexible electrical power delivery to the net
1. At high power demand, more electricity and less hydrogen are produced
2. At low power demand, more hydrogen and less electricity are produced
4. The power process can run closer to design load; thus the average efficiency is increased
1. Power production not directly dependent upon net power requirement
2. The efficiency of a power process is highest when it is running at the design load

The external oxygen supply can be produces by a cryogenic- or a none cryogenic air separation unit. Examples of suitable fuel types are: Coal, gasified coal, biomass, gasified biomass, natural gas and pet coke. The electricity production unit can be steam turbines, gas turbines, motors, etc...

The power process produces water that may be supplied to the electrolysis unit. The oxyfuel power process can provide up to 100 % of the water required for the electrolysis unit. The produced electricity that is not supplied to the water electrolysis is delivered to a system power grid. Oxygen from the water electrolysis can supply up to 30 % of the process oxygen requirement.

Next >>