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13. Transport by Ship
For decades, liquefied natural gas and liquefied petroleum gases (LPG) such as butane and propane have been transported on a large scale by sea in tanker ships. Similar transport also exists for CO2, of course on a smaller scale, due to the more the limited demand.
The properties of cryogenic CO2 are not that different from those of the above mentioned gases and the same technologies may be applied. Practically, CO2 is compressed to 6 bar, and then cooled to -55 °C in a special cooling plant, which operates basically on the same principle as a refrigerator. Tankers can provide transport between the production plant and the storage location. Some space must also be arranged on the production site for temporary storage of the cryogenic CO2. The technology for the loading and offloading of such products is well known and developed.
The advantages of transport by ship compared to pipeline transport are flexibility in the destination of the CO2 and rapid deployment of the transportation route.

4. Syngas Purification
The gas leaving the gasifier still contains fine dust particles from the incombustible constituents in the fuel, so-called fly ash and small quantities of all kinds of volatile substances, such as ammonia, that may damage the equipment downstream.
The fly ash is trapped by fine-meshed filter cartridges made of ceramic material, which can withstand the high temperatures. The trapped fly ash is sent to the collection silos by using a lock system. Fly ash has numerous useful applications in the construction industry. For example, they can be mixed with cement, in order to improve the mechanical properties of the cement, worked into concrete, etc.
The volatile constituents such as ammonia and hydrochloric acid are readily soluble in water. Together with any residual dust, they are extracted from the syngas in the scrubber, in which the gas is brought into close contact with water. The high pressure renders all the volatile constituents readily soluble in the water. Any residual fly ash is also captured.
The contaminated water is chemically and physically purified for reuse in the scrubber. The volatile substances are further treated, neutralized or eliminated so that no hazardous substance is released into the environment.

3. Gasification
The coal gasification process has been around since the early 20th Century. Historically, synthetic gas was produced for use as town gas, for the production of all kinds of chemicals and for the production of hydrogen which is a raw material in the production of ammonia (artificial fertilizer production).

There are numerous gasification technologies, but the technology applied by C.GEN, gasification with pure oxygen where fuel and oxygen are mixed flow, is the most widespread for electricity generation with CO2 capture on the basis of imported coal.

The heart of a gasification plant is the gasifier. This is a barrel with an internal pressure of 45-70 bar and with a temperature of 1 400- 1 600 °C. According to the technology, the inner walls are protected from the high temperatures either by refractory material or by water cooled pipes where the water is subsequently converted into steam.
The action of pressure and temperature triggers, the following exothermic reactions:

C + ½ O2 => CO
C + O2 => CO2
CO + H2O < = > CO2 + H2
H2 + ½ O2 => H2O

The produced synthetic gas (syngas) therefore consists mainly of carbon monoxide, carbon dioxide, hydrogen and water.
The fuel also contains other elements, such as small quantities of sulphur, nitrogen, chlorine, etc. They are converted into H2S (hydrogen sulphide), HCl (hydrochloric acid), NH3 (ammonia), etc. However, these volatile substances can be easily removed from the syngas (see below).

The solid fuels also contain incombustible constituents such as sand, clay and minerals. About half of these will melt and stick to the walls of the gasifier, then flow down slowly into a water bath where they cool down to form glassy flakes or slag. The solidified slag locks up a number of impurities present by nature in the solid fuel in its glassy structure which protects from ever releasing them back into the environment.

Besides the slag, also fine inert particles, called fly ash, are produced. This ash is entrained in the gas flow and captured downstream. Both slag and fly ash can be reused in the construction industry (concrete and cement production, road-building).

2. Oxygen Production
Ambient air, consisting of 21% oxygen, 78% nitrogen and 1% other gases, is dried and purified in the air separation plant. For this process, the air is compressed to 5 bar and then cooled to around -190°C. At this temperature, oxygen becomes liquid, while the nitrogen, which has a lower boiling point, remains gaseous. The two elements can then easily be separated from each other. Afterwards, the liquid oxygen is converted back to gas in a heat-exchanger, recovering the cold/heat.

Approximately 120 t/h of oxygen and nitrogen is then brought to the right pressure with compressors. The oxygen is fed to the gasifier, while the nitrogen is used to dilute the hydrogen before combustion in the gas turbine.

10. Steam turbine
The steam from the HRSG, together with the steam produced in the gasification plant, is expanded in a steam turbine which drives a generator. The steam turbine generator supplies electric energy to the high voltage transmission grid.
The expanded steam from the steam turbine is condensed in a condenser which is in turn cooled by seawater. The condensate is used again and sent back to the HRSG and gasification plant.

8. Gas turbine
The hydrogen gas, with a pressure of approximately 30 bar, is diluted with nitrogen originating from the air separation installation to a fuel with a hydrogen content of around 60%. This dilution allows the mixture to be used in a slightly modified, modern and efficient F Class gas turbine. The gas turbine drives a generator that produces electricity for the high voltage transmission grid. The outlet gases from the turbine are sent to the heat recovery steam generator, which recuperates the heat present in the exhaust gas for steam production.

1. Fuel Preparation
Coal is offloaded from cape-size ships and stored locally.
A reserve of about 30 000 tons of coal, which should be enough for ten days at full capacity, is stored temporarily in covered silos on the C.GEN production site. Covered conveyor belts bring the coal from the storage to the coal preparation plant.
In the coal preparation plant, the coal is grinded and if necessary dried. From there, the coal is sent to the gasifier and transformed into syngas. The syngas is then transformed into CO2 and purified hydrogen. The hydrogen is sent to the gasturbine whereas the CO2 is prepared for transport and storage.
Given the highly efficient purification and desulphurization equipment used, very low sulphur emission levels can be expected.