Configurations and related processing schemes of direct or indirect (or both) intra-plants and thermally coupled heating systems synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of direct or indirect (or both) intra-plants and thermally coupled heating systems synthesized for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Configurations and related processing schemes of inter-plants and hybrid, intra- and inter-plants' direct or indirect heating systems synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of inter-plants and hybrid, intra- and inter-plants' direct or indirect heating systems synthesized for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Plants and methods are presented for crude feed pre-processing before feeding the crude feed into a crude unit or vacuum unit. Pre-processing is preferably achieved with a combination of a preflash drum and a preflash column that allows for high-temperature treatment of the liquids and separate vapor phase handling, which advantageously enables retrofitting existing plants to accommodate lighter crude feeds.

Configurations and related processing schemes of direct or indirect inter-plants (or both) heating systems synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of direct or indirect inter-plants (or both) heating systems synthesized for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Configurations and related processing schemes of specific inter-plants and hybrid, intra- and inter-plants waste heat recovery schemes for thermal energy consumption reduction in integrated refining-petrochemical facilities synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of specific inter-plants and hybrid, intra- and inter-plants waste heat recovery schemes for thermal energy consumption reduction in integrated refining-petrochemical facilities synthesized for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Configurations and related processing schemes of specific direct or indirect inter-plants integration for energy consumption reduction synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of specific direct or indirect inter-plants integration for energy consumption reduction for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Configurations and related processing schemes of specific inter-plants and hybrid, intra- and inter- plants waste heat recovery schemes for thermal energy consumption reduction in integrated refining-petrochemical facilities synthesized for grassroots medium grade crude oil semi-conversion refineries to increase energy efficiency from specific portions of low grade waste heat sources are described. Configurations and related processing schemes of specific inter-plants and hybrid, intra- and inter- plants waste heat recovery schemes for thermal energy consumption reduction in integrated refining-petrochemical facilities synthesized for integrated medium grade crude oil semi-conversion refineries and aromatics complex for increasing energy efficiency from specific portions of low grade waste sources are also described.

Oxidative dehydrogenation of paraffins to olefins provides a lower energy route to produce olefins. Oxidative dehydrogenation processes may be integrated with a number of processes in a chemical plant such as polymerization processes, manufacture of glycols, and carboxylic acids and esters. Additionally, oxidative dehydrogenation processes can be integrated with the back end separation process of a conventional steam cracker to increase capacity at reduced cost.

A process for the removal of residual sulfur compounds from rich liquid caustic is disclosed where a single column containing two reaction zones catalytically oxidizes mercaptans to disulfide oils. The second reaction zone utilizes a bundle of vertical hanging fibers and is maintained as a gas continuous phase comprising from about 20% to about 100% by volume vapor. This process is especially useful as part of a hydrocarbon desulfurization process flow scheme.

Processes for hydrotreating a hydrocarbon stream in which a separation zone and a stripping zone is disposed between two hydrotreating reactors. The stripping zone may comprise a portion of the second hydrotreating reactor. The separation zone may comprise two separator vessels. A separator vessel may include the scrubbing zone to receive a scrubbing fluid, for example, steam, hydrogen, or heated effluent, and remove H.sub.2S and NH.sub.3. A divided wall separator may be used. Vapor from the separator vessels can be recycled in the system.