Plants Synthesis Gas

They used a Ni-containing catalyst. In contrast to steam reforming of methane, methane partial oxidation is exothermic. However, the partial oxidation requires pure oxygen, which is produced in expensive air separation units that are responsible for up to 40% of the cost of a synthesis gas plant (2) (in contrast, the steam reforming process does not require pure oxygen). Therefore, the catalytic partial oxidation of methane did not attract much interest for nearly half a century, and steam reforming of methane remained the main commercial process for synthesis gas manufacture. 

Most of the synthesis gas produced is captive. That is, it s consumed by the manufacturer. Synthesis gas plants are normally integrated into the adjacent application plant. When there is a two-party transaction involved, the properties of the synthesis gas stream are normally specified in a contract. There are no universally accepted standards that apply with this stream. 

Synthesis gas is made by decomposing methane (from natural gas) in the presence of water. The reaction takes place at high pressure and temperature in the presence of a catalyst. The proportion of H2 and CO depends on the amount of CO2 that is left in the product stream or is recycled to be converted to CO/Ho. Most synthesis gas plants are built adjacent to the plants where the synthesis gas will be used. 

Methanol process. BASF introduced high-pressure technology way back in I960 to make acetic acid out of methanol and carbon monoxide instead of ethylene. Monsanto subsequently improved the process by catalysis, using an iodide-promoted rhodium catalyst. This permits operations at much lower pressures and temperatures. The methanol and carbon monoxide, of course, come from a synthesis gas plant. 

Estimate the required utilities for the synthesis gas plant described in the previous four problems. 

A modern synthesis gas plant can be coupled to a gas/steam combined cycle. The gases could in a future installation be consumed at enhanced efficiency by a hybrid fuel cell/combined cycle plant, notably if the fuel cells were equipped with concentration cell circulators. See Section 5.2.13. 

It is not intended to discuss the specific problems of the synthetic ammonia production but to localize those areas of an industrial chemical process which cause consumptions. The analysis comprises the synthesis gas plant using methane in a reforming process and the ammonia production. The use of methane is an arbitrary choice. The analysis of the coupled processes is necessary to give a realistic impression and to allow a qualified judging of the units and systems. 

The upper part of Fig. 1 shows the synthesis gas plant which is fed from the right-hand side with methane (stream l) and air (stream 2) for a combustion process to match the heat requirements of the synthesis gas process. The combustion process delivers the exhaust gas (stream 3). The synthesis gas is produced by methane, water vapor and air (streams U, 5 6) in a primary and secondary reformer and a converter (units REF1, REF2 and CON). The raw gas (stream 28) passes the gas conditioning (SEPl) which has been detailed in Fig. 3 and the synthesis gas (stream 29) enters the ammonia plant shown in the lower part of Fig. 1. The ammonia... 

Since the synthesis-gas plant and ammonia plant operate in series, it follows that... 

The availability consumptions in a synthesis gas and ammonia plant have been analyzed and localized it is shown that the synthesis gas plant—due to the dominating influence of the reforming reactors—produces 1 times the consumption of the ammonia works. 

The convective reactor concept is especially attractive for small-sized synthesis gas plants (<5,000 Nm /h). The reactor can be prefabricated on a skid such that construction costs can be minimized through shop fabrication. 

Figure 2.26 Synthesis gas plant of a 2,500 MTPD methanol plant with two-step reforming + prereforming, Statoil, Tjeldbergodden. The prereformer vessel is shown to the light. The ATR reformer is to the left of the reformer furnace.

Today, most of the carbon dioxide coming on to the market as industrial gas is recovered from CO2 sources which already exist. A CO2 source is understood to be gases and off-gases with a significant CO2 content. About 70% of the COj on the European market is actually recovered from synthesis gas plants (see also Section 5.2.3). Only a small part of the CO2 is generated by the combustion of fossil fuels, preferably natural gas. This usually occurs in smaller units (capacity < 2 t h ), which are so far away from a suitable CO2 source that the transport to the consumer is economically not feasible. 

COj-fraction from add-gas scrubbings in ammonia or other synthesis gas plants or H,-generation plants (cf. Section 5.2) 1.0 to 1.2 bar... 

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