Ethylene and Propylene Production

The manufacture of ethylene and propylene is one of the most important operations of the petrochemical industry. In that process, ethylene and propylene are formed from the thermal cracking of other hydrocarbons, such as ethane, propane and naphtha. The mixture resulting from the thermal cracking is very complex. Hence, the mixture has to be separated into relatively pure ethylene and propylene, ethane and propane to be used as a recycle, methane and hydrogen to be used as fuel, and heavier products to be used for gasoline. A typical refinery gas feed to the separation system of this process contains hydrogen, ethylene, methane, ethane, propane, propylene and lower compositions of other heavy hydrocarbons. The distillation sequence most commonly used for the separation of the mixture is shown in Figure 7.

In a high pressure plant (no refrigeration is needed for condensation of products), the distillation sequence consists of five distillation columns:

1. Demethanizer

2. Deethanizer

3. Ethylene/ethane separator

4. Depropanizer

5. Propylene/propane separator.

Both the propylene/propane and the ethylene/ ethane separator require high towers with large diameters because such mixtures contain components with very close relative volatilities. A plant that uses the configuration described here was built by Pullman Kellogg Inc., Houston, Texas.

In the case of a lower pressure plant, the deethanizer precedes the demethanizer because refrigeration is required for the feed of the demethanizer. So, by placing the deethanizer first, important utility savings are obtained.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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