**1. Introduction**

Generally, ethylene is one of the most important building blocks in the chemical industry, which is widely used to produce a wide range of products and intermediates, such as polyethylene, ethylene oxide, ethylbenzene, and ethylene dichloride [1,2]. Although the catalytic conversion of hydrocarbons to ethylene is beneficial, the steam thermal cracking of ethane, LPG, naphtha, and gasoline is the most popular method to produce ethylene. Typically, a wide range of hydrocarbons is produced in the thermal cracking process. Acetylene as a by-product of cracking unit has an enormous effect on the quality of product and must be removed from the olefin streams prior to further processing [3]. Typically, the minimum required purity of ethylene in the polymerization processes to produce polyethylene is about 99.90% and the maximum allowable limit of acetylene is 5 ppm known as polymer-grade ethylene. Acetylene decreases the catalyst activity in the ethylene polymerization unit, and can produce metal acetylides as explosive compartments. In this regard, several technologies have been proposed to decrease the acetylene concentration in the effluent product from thermal

cracking furnaces, including acetylene hydrogenation to ethylene and acetylene separation from the main stream [4]. Since the separation process is expensive and dangerous, the catalytic hydrogenation is more popular and attractive.
