Selection of thermodynamic parameters for PROII (formaldehyde)

The SRK equation, used in gas and refining processes, can calculate K values, enthalpy, entropy, gas density, and liquid density (with limitations); it is generally not used for highly non-ideal systems, supports free water, but does not support VLLE. PR equation, main refining process; capable of calculating K value, enthalpy, entropy, and gas density; not suitable for highly non-ideal systems; supports free water, but does not support VLLE. The modified SRK and PR equations can be used to calculate K values, enthalpy, entropy, and gas density; they are applicable to non-ideal systems, do not support free water, and can be used in VLLE. The Uniwaals equation can be used to calculate the K value, enthalpy, entropy, and gas-liquid densities; it is particularly suitable for highly non-ideal systems when the group contribution parameters are provided from a database or by the user. Used for low and medium pressure systems; it does not support free water but supports VLLE. The BWRS equation can be used to calculate the K value, enthalpy, entropy, and gas-liquid densities, and is applicable to light and heavy hydrocarbon components in refineries. However, it does not support strict two-phase behavior. Free water is supported, while VLLE is not. The hexamer equation, suitable for HF alkylation and refrigerant synthesis, can calculate K values, enthalpy, entropy, and gas density, and supports strict two-phase behavior. Applicable when there is only one hexamer component and no water is present. The LKP equation can be used to calculate the K value, enthalpy, entropy, and gas-liquid densities; it is primarily applied in light hydrocarbon systems and reforming systems containing large amounts of hydrogen. It can be used in the VLLE system, but not for free water. The NRTL liquid activity equation is used for VLE or VLLE systems and does not support free water. It is usually used for non-ideal systems, particularly immiscible systems. Used to calculate the K value. The Uniquac liquid activity equation is used for VLE or VLLE systems and does not support free water. It is usually used for highly non-ideal systems, particularly immiscible systems. Used to calculate the K value. The Unifac liquid activity equation is used for VLE or VLLE systems and does not support free water. The Unifac group contribution method is commonly used for low-pressure, non-ideal systems. Typically, the number of limiting groups is less than 10, or even fewer, and the system contains low-molecular-weight polymers. Calculate the K value. The modified Unifac liquid activity equation is used for VLE or VLLE systems and does not support free water. The Unifac group contribution method is commonly used for low-pressure, non-ideal systems. Typically, the number of limiting groups is less than 10, or even fewer, and the system contains low-molecular-weight polymers. Calculate the K value. The Wilson equation, used for VLE systems, does not support free water. Suitable for mildly non-ideal systems. Calculate the K value. The Van laar equation is used for VLE and VLLE systems and does not support free water. It is usually used in mildly non-ideal systems. Calculate the K value. The Margules equation, used for VLE and VLLE systems, does not support free water. It is usually used in mildly non-ideal systems. Calculate the K value. Regular Solution, used for VLE and VLLE systems, supports free water. It is usually used in mildly non-ideal systems. Calculate the K value. The Flory-Huggins equation, used for VLE and VLLE systems, does not support free water. It is more suitable when the sizes of the components in the system mixture differ significantly, such as in polymer solutions. Calculate the K value. Henry's law for non-compressible components is used to predict gas solubility, particularly in simulating supercritical components using the liquid activity approach. It is particularly suitable for the dissolution of trace hydrocarbons in water under environmental conditions. Calculate the K value. Not applicable to free water. The HOCV equation is used to predict gas fugacity, steam enthalpy, entropy, and density. It is particularly suitable for systems with dimers in the gas phase, such as carboxylic acid systems. The liquid activity method must be used together with HOCV. Not applicable to free water; can be used for VLLE. The truncated virial gas fugacity is used to predict vapor fugacity. It is particularly suitable for systems with dimers in the gas phase, such as carboxylic acid systems. The liquid activity method must be used together with HOCV. Not applicable to free water; can be used for VLLE. Idimer vapor fugacity: predicts gas fugacity, vapor enthalpy, entropy, and density. It is particularly suitable for systems with dimers in the gas phase, such as carboxylic acid systems. The liquid activity method must be used together with IDIMER. Not applicable to free water; can be used for VLLE. RK, the gamma mixing heat, is used to correct ideal enthalpy data. It must be used in conjunction with the liquid activity coefficient method. Not applicable to free water and VLLE. Special package: Ethanol, used for predicting VLE and LLE systems. Not applicable to free water. Used to handle systems containing alcohols, water, and other polar substances. It is commonly used in systems containing alcohols, especially for azeotropic distillation in alcohol plants for dehydration. Calculate the K value. Free water is not supported; VLLE is supported. Ethylene glycol, used to predict VLE and LLE systems. Free water is not supported. Systems containing ethylene glycol, water, and other components are calculated using special SKRM two-effect data and the a parameter. This equation is commonly used for triethylene glycol, or diethylene glycol and ethylene glycol. It is particularly suitable for TEG dehydration plants. Calculate the K value. The acid water equation is used to predict VLE and LLE systems. Free water is not supported. The API/EPA SWEQ (acid balance) method is used to simulate the components of acid water, namely NH3, H2S, CO2, and water. It is usually used for acid water with an acid content of less than 30% (by weight). Calculate the K value. GPA acid water, used for predicting VLE and LLE systems. Free water is not supported; it uses the GPSWAT method related to gas treatment to simulate acidic water containing water, NH3, H2S, CO, CS2, MeSH, EtSH, and CO2. SRKM is used for all other components. It has a wider range of applications than the Sour package. Calculate the K value. The ammonia equation is used to predict VLE and LLE systems. Free water is not supported. The K-E method is used to simulate the reaction equilibrium of MEA, DEA, and DIPA, as well as the correction of the residence times for MDEA and DGA. The reaction heat is calculated by correcting for the ideal liquid enthalpy. The ammonia equation is mainly used for gas humidification in single-ammonia systems. Calculate the K value. User-defined: User-defined programs can calculate the equilibrium K value, as well as the enthalpy, entropy, and density values of the gas and liquid phases. Solid dissolution method: Van’t Hoff solubility, using the Van’t Hoff ideal solution equation to calculate the K value for solid-liquid equilibrium in systems that are nearly ideal non-electrolytic systems. Transportation and special properties: Transportation properties, which are used to describe the transport characteristics of substances, including gas-liquid viscosity, thermal conductivity, and liquid surface tension. The liquid diffusion rate can be calculated by selecting Diffusivity. The truncated virial gas fugacity is used to predict vapor fugacity. It is particularly suitable for systems with dimers in the gas phase, such as carboxylic acid systems. The liquid activity method must be used together with HOCV. Not applicable to free water; can be used for VLLE. Idimer vapor fugacity: predicts gas fugacity, vapor enthalpy, entropy, and density. It is particularly suitable for systems with dimers in the gas phase, such as carboxylic acid systems. The liquid activity method must be used together with IDIMER. Not applicable to free water; can be used for VLLE.

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