Amine Guard process

CO conversion is achieved in the HT and LT shift over standard catalyst, while C02 is removed either in the BASF-aMDEA, the UOP-Benfield or the UOP-Amine Guard process. Remaining carbonoxides are reconverted to methane in catalytic methanation to trace ppm levels. 

Union Carbide has developed Amine Guard, which essentially eliminates corrosion in amine systems (32—35). It permits the use of substantially higher amine concentrations and greater carbon dioxide pick-up rates without corrosive attack. This results in an energy requirement comparable to that of the carbonate process and allows the use of smaller equipment for a specific C02-removal appHcation thereby reducing the capital cost. 

The process is capable of achieving higher solubiHties of CO2 in the solution without the corrosion problems encountered with amine systems before the advent of Amine Guard. The Sulfinol process is used in over 50 plants worldwide nevertheless, it is used less often than the amine or carbonate processes. 

Amine Guard A process for extracting acid gases from refinery streams by scrubbing with an alkanolamine. Many such processes have been developed, this one was developed by the Union Carbide Corp. and uses monoethanolamine. It has been used to purify hydrogen produced by steam reforming. In 1990, over 375 units were operating. 

A corrosion inhibitor is used with this process. With the Amine Guard inhibitor, the MEA concentration in the circulating solution can be increased to 30% from a normal 20%. Hence, the circulating rate can be decreased by 33% and the heat requirements are decreased by 43%. 

Two examples of this technology are the Amine Guard FS Process and the Amine Guard II Process. A comparison of the two processes is given in Table 5.35200. 

A number of different acid gas removal processes have been used for removal of COj from synthesis gas. They include MEA with UCAR Amine Guard, Selexol, Rectisol, Sulfinol and hot potassium carbonate. The flow scheme depicted in Figure 3 shows an amine-based CO2 removal system. 

Kosseim, A. J., McCullough, J. G., and Butwell, K. F., 1984, Treating Acid Sour Gas Corrosion-Inhibited Amine Guard ST Process, Chem. Eng. Prog., October, pp. 64-71. 

For most of applications, it is required to purity BPA from the mentioned byproducts before its further processing. Therefore, the BPA production line consists of a condensation reactor and the units responsible for the BPA purification. Among them, there is usually a unit for crystallization of the BPA-phenol adduct and stripping tower, where the adduct is cracked and phenol is recovered (as it was described earlier). There are also a recrystallization unit, a cracker for the o,p-isomers of BPA and a wastewater treatment facility. Additionally, there may be an isomerization unit, where the mother liquor is contacted with an acidic or amine-based ion-exchange resin as the isomerization catalyst under the conditions effective to convert the BPA byproducts to BPA. Next, the effluent from the isomerization zone can be contacted with a solid particle guard bed, composed of alumina, titanium oxide, silica, zirconium oxide, tin oxide, charcoal or silicon carbide [55]. This guard... 

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