Steam generation boiler feedwater

Description Gas feedstock is compressed (if required), desulfurized (1) and sent to the optional saturator (2) where some process steam is generated. The saturator is used where maximum water recovery is important. Further process steam is added, and the mixture is preheated and sent to the pre-reformer (3), using the Catalytic-Rich-Gas process. Steam raised in the methanol converter is added, along with available C02, and the partially reformed mixture is preheated and sent to the reformer (4). High-grade heat in the reformed gas is recovered as high-pressure steam (5), boiler feedwater preheat, and for reboil heat in the distillation system (6). The high-pressure steam is used to drive the main compressors in the plant. 

Figure 13.8 The grand composite curve for the whole process apparently requires only high-pressure steam generation from boiler feedwater.

Exampie A.3.1 The pressures for three steam mains have been set to the conditions given in Table A.l. Medium- and low-pressure steam are generated by expanding high-pressure steam through a steam turbine with an isentropic efficiency of 80 percent. The cost of fuel is 4.00 GJ and the cost of electricity is 0.07 h. Boiler feedwater is available at 100°C with a heat capacity... 

Economizers Economizers improve boiler efficiency by extracting heat from the discharged flue gases and transferring it to feedwater, which enters the steam generator at a temperature appreciably lower than the saturation-steam temperature. 

Process Steam Generation. Steam generated in the process sections of the plant may be at the highest plant pressure level or an intermediate level. Also, the process area may have fired boilers, waste heat boilers, or both. There may be crossties between utility and process generated steam levels. Enough controls must be provided to balance far-ranging steam systems and protect the most critical units in the event of boiler feedwater shortage situations. 

Steam Generator Produces steam from condensate or boiler feedwater by combustion of waste oil, tars, or off-gas in direct-fired equipment. 

The profile of steam generation is shown against the grand composite curve in Figure 16.35a. The process can support both boiler feedwater preheat and steam generation, b. Maximum superheat temperature... 

It is proposed to provide process cooling by steam generation from boiler feedwater with a temperature of 100°C. 

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