AdWinCombined™

AdWinCombined™ is an evolution of AdWinMethanol^®technology and Uhde Ammonia technology. It allows the production of both products methanol and ammonia in a highly integrated plant concept which ultimately leads to savings in OPEX of up to 10% and CAPEX of up to 30% compared to two separate conventional process plants.

The process concept features the simultaneous operation of both product plants at nameplate capacity but also provides the freedom of operation at partial loads. Furthermore single product operation modes are possible, i.e. one product line (methanol) can continue to operate while the other product line (ammonia) is in shut down and vice versa.

AdWinCombined™, a joint process development of thyssenkrupp and GasConTec, is based on proven equipment, but utilises an advanced and highly integrated process arrangement (see simplified process flow diagram below) with a single syngas production island, the core of which is an oxygen-driven catalytic partial oxidation reactor (autothermal reactor). The set-up of the methanol synthesis corresponds to that of AdWinMethanol^® with two sequential isothermal reactor stages and an intermediate condensation. The purge gas from the methanol synthesis is used as feed stock for the ammonia unit based on Uhde Ammonia technology.

The main advantages of AdWinCombined™ technology for the owner/operator:

Higher reliability
Less EPC cost by up to 30%, resulting also in less Total Installed Cost (TIC), compared to two separate units
Reduced natural gas consumption by up to 10%
A high flexibility of operating the complex
Reduced environmental footprint
Reduced maintenance cost

Process flow diagram: AdWinCombined™

Process Highlights

AdWinCombined^TM uses only a catalytic POX (ATR) for syngas production and a steam reformer is not needed. Deleting the steam reformer reduces CAPEX and makes the operation of the plant more reliable and simpler. Furthermore, the previous pressure limitation of the reforming falls away and so it is possible to operate the syngas production at elevated pressure which leads to smaller equipment and smaller pipelines.

Even more, the higher pressure in the syngas production section leads to much smaller pressure differences over the two syngas compressors, the methanol and ammonia syngas compressor. This leads to lower CAPEX and a much higher reliability of the plant.

In contrast to conventional ammonia plants only a HT shift is used to increase the hydrogen content. A low temperature shift, with a costly and sensitive catalyst, is not needed. By varying the flow rate through the HT shift, the production ratio of methanol to ammonia can be adjusted.

Only a simple and energy-efficient CO₂ bulk removal is required. A complete CO₂ removal as in conventional ammonia plants is not needed. Since the CO₂ removal unit is located upstream of the methanol synthesis, it ensures a CO₂-low syngas, which results in a reduced hydrogen demand for the desired methanol production.

For the preparation of a suitable syngas for the ammonia synthesis no methanation is required in contrast to conventional ammonia plants. AdWinCombined^TM uses a robust and flexible pressure swing adsorption (PSA) system that ensures the production of high purity hydrogen from the purge gas of the methanol synthesis.

In contrast to conventional methanol technologies, AdWinMethanol^® employs state of the art isothermal reactor types in both reactor stages. This does not only simplify the design and operation of the reactors, but also significantly reduces the catalyst volume required in the second stage.

Furthermore, by an intermediate condensation the product methanol is separated and two positive effects can be achieved. Firstly, the recycle flow - and hence the flow to the second reactor stage - can be reduced. Secondly, the methanol removal increases the driving force (equilibrium) for the methanol synthesis, resulting in higher CO_x conversion rates and a higher methanol production.

Pure nitrogen from the air separation unit is mixed with pure hydrogen upstream of the ammonia syngas compressor. Due to the absence of inert components in the syngas, the ammonia plant is considerably simplified compared to conventional arrangements.

Integration vs. stand-alone solution

Due to the superior new concept of a highly integrated ammonia/methanol co-production complex significant benefits can be achieved, shown in the following table.