STEAM CRACKING FOR ETHYLENE PRODUCTION
HEAT EXCHANGER SYSTEMS FOR THE STEAM CRACKING PROCESS IN ETHYLENE PLANTS
Ethylene and other olefin products are produced by thermal cracking of gaseous feedstocks such as ethane, propane and PG or liquid feedstocks such as naphtha and gas oil or pre-processed hydrocracker output products.
The steam cracking process occurs in the radiant coils of a pyrolysis furnace where gas flows at low pressure and temperatures between 750 °C and 900 °C (1,382 °F to 1,650 °F) depending on the feedstock used. The olefins formed are chemically unstable at these temperatures.
The highly reactive cracked gas must be quickly quenched below a critical temperature within a very short interval “residence time” of milliseconds to provide the highest yield of ethylene. The critical temperature range for the production of ethylene lies between 650 °C and 700 °C (1,202 °F to 1,292 °F).
In the past, the standard practice for cooling the pyrolysis furnace effluent gas was by direct oil or water injection. Today such methods are unacceptable.
Nowadays the rapid cooling or quenching takes place in heat exchangers called Transfer Line Exchangers. These heat exchangers use the high heat content to produce high pressure steam. Figure 1 illustrates a typical furnace and Transfer Line Exchanger layout in a steam cracking process.
Schmidt’sche® Transfer Line Exchangers have been linked to the history of steam cracking in ethylene pyrolysis furnaces for a long time. The reliability and flexibility of the Schmidt’sche® Double Tube designs play an important role in the development of modern furnace technology for steam cracking, where long run lengths, high yields, selectivity and equipment availability determine the commercial success of the steam cracking operation.
SCHMIDTSCHE SCHACK´S HEAT EXCHANGER SYSTEMS AND SERVICES FOR THE STEAM CRACKING PROCESS:
- Schmidt’sche® Transfer Line Exchanger (TLE)
- Round type Transfer Line Exchanger (TLE)
- Linear type Transfer Line Exchangers (TLE)
- Bathtub type Transfer Line Exchanger (TLE)
- Quick Quencher Transfer Line Exchanger (TLE)
- Secondary Transfer Line Exchanger (TLE)
- Tertiary Transfer Line Exchanger (TLE)
- Steam Drum