Maximum Steam Export

A maximum export steam plant is defined as a plant that makes the maximum practical quantity of export steam, without auxiliary firing. 

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Figure 1. Steam/Methane Reforming with Maximum Steam Export...

Note that the limited export steam plant makes less than half as much export steam as the maximum steam export case, but also uses less natural gas. At the same time, the limited steam export plant capital cost is higher, because of the addition of the air preheat unit. 

The steam value and fuel price typically determine which of these two cases is the most economic. A high steam value (relative to fuel price) favors the Maximum Steam Export Case. A high fuel price and a low steam value (relative to fuel price) favor the Limited Steam Export Case. 

Figure 3 is a plot of natural gas price versus steam value. For a given natural gas price, if the steam value is above the curve, then maximum steam export is favored. But if the steam value is below the curve, then CAP... 

The preliminary data obtained returned an efficiency for the OSD process (j osd) in the order of 72% versus a literature value of the steam methane reforming (SMR) ranging from 73% (no steam export valorization) to 80% (maximum steam export valorization). Furthermore, in order to make a fair comparison, the SMR should be penalized for the CO2 capture. 

A minimum export steam plant is defined as a plant that optimizes heat recovery in the plant to the maximum extent possible. This is often done when the value of steam is essentially zero or the price of the feedstock and fuel are exceptionally high. Minimum steam export is often achieved by first increasing the SMR process gas inlet temperature and then the combustion air preheat temperature, both of whieh reduce the fired duty of the SMR. Typical temperatures are 1150°F for the process gas and 900°F for the air preheat. These changes reduce the export steam to a low level, but typically not completely to zero. Additional modifications are required to reduce the export steam to an absolute minimum. 

The maximum speed of the LH2 carrier is about 17.5 kn (32.4 km/h). The propulsion power is 41 MW. The propulsion of the SWATH carrier is based on a steam-injection gas turbine with an efficiency of 50% (Wursig, 1996). The investment for the SWATH carrier is indicated at about 440 million, including five LH2 tanks. The investment for one LH2 tank is 40 million. The investment for the LH2 terminals (both export and import terminal) is indicated at about 820 million (G. M. Wursig, Germanischer Lloyd, Hamburg, personal communication, January 1999). 

Lurgi 01 Gas Chemie GmbH Phthalic anhydride O-xylene, naphthalene Multi-tubular reactor oxidizes o-xylene at high yield with maximum heat recovery for export HP steam 110 1998... 

The heating value of a typical biomass is sufficient to produce steam in excess of that required by the activated process if the system has been designed for maximum thermal efficiency. This can be especially important to developing countries who have large supplies of biomass such as rice hulls or coconut shells and who are currently contemplating the manufacture of activated carbon for export or local water treatment. 

Advanced Reforming Technology. The advanced reforming technology (ART) reformer concept (31) developed by KTI SpA (now Technip) is a convective reformer and is characterized by utilizing up to the maximum extent of the waste heat available in the steam-reforming process for the process itself and not for the production of export steam. This results in a reduced operating and investment costs. 

Table 3 gives a typical feed and utility summary for a maximum export steam plant, as defined above. 

Table 3. Maximum Export Steam Feed and Utility Summary...

A limited export steam plant is defined as a plant that makes some export steam but significantly less than the maximum. This is typically achieved by adding a combustion air preheat unit (CAP). This unit consists of a modular heat exchanger that heats the combustion air to the SMR by heat exchange with the flue gas from the SMR. The hot combustion air reduces the fuel requirement for the SMR, which in turn reduces the steam production. 

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