Practical guidelines temperature

This recommended practice applies to equipment in refineries, petrochemical facilities, and. chemical facilities in which hydrogen or hydrogen-containing fluids are processed at elevated temperature and pressure. The guidelines in this recommended practice can also be applied to hydrogenation plants such as those that manufacture ammonia, methanol, edible oils, and higher alcohols. 

Dew-point measurement is a primary method based on fundamental thermodynamics principles and as such does not require calibration. However, the instrument performance needs to be verified using salt standards and distilled water before sampling (see Support Protocol). To obtain accurate and reproducible water activity results with a dew-point instrument, temperature, sensor cleanliness, and sample preparation must be considered. Equipment should be used and maintained in accordance with the manufacturer s instruction manual and with good laboratory practice. If there are any concerns, the manufacturer of the instrument should be consulted. Guidelines common to dew-point instruments for proper water activity determinations are described in this protocol. The manufacturer s instructions should be referred to for specifics. 

In practice, the reduction temperature is raised stepwise by using the exothermic heat of ammonia formation. The progress of the reduction is controlled according to the catalyst temperature and the water concentration by adjustment of the synthesis gas flow. As a rough guideline, the water content of the gas effluent from the catalyst should not exceed 2-3 g/m3 (STP). Under these conditions, depending on its size and operating pressure, a synthesis converter with a fresh load of oxidic catalyst attains its full production capacity in 4-10 d. 

In terms of stability, determination of whether the forms are monotropic or enantiotropic is of considerable benefit, as such knowledge will theoretically aid the formulator in determining the likely stability of the material at any stated temperature. In practice, the differentiation between these forms may be a nontrivial task due to the existence of kinetically stable metastable polymorphs. A number of authors (e.g., 4,16-18) have used the guidelines developed by Burger (19), which are summarized in Table 3.1. 

For temperatures >500°C, put tubes in furnace. Same area of application, guidelines, and good practice as empty tube. Section 16.11.6.3. Radiant heat flux in furnaces 30 to 80 kW/m. Reformers ... 

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