Introduction

Propane Dehydrogenation (PDH) is a process that describes the production of Propylene. Propane Dehydrogenation is considered as an essential process, since the outcome of the process is ranked as the second biggest volume in petrochemical industries after Ethylene. Propylene production can be achieved by several ways including Propane Dehydrogenation, olefin metathesis, and Methanol to olefin (MTO) which starts by converting the natural gas to Methanol for further processing to produce the desired product Propylene. There are many valuable products that can be derived from Propylene such as Polypropylene.

Polypropylene is produced via polymerization of Propylene, and it has a large demand in the world market since it is characterized by high stiffness and high chemical resistance and implemented in packaging and manufacture of containers. Moreover, Propylene is considered as a byproduct of steam cracking process and fluid catalytic cracking (FCC) process hence, its value is largely dependent on the crude price.

The process of Propane Dehydrogenation is operated at mild pressure (0.5 – 3.5) bar, and high temperature (500 – 650) C introducing Platinum (Pt) or Chromium oxide (Cr2O3) as a catalyst for the reaction. The reaction will produce the desired product which is Propylene and Hydrogen as a byproduct. Furthermore, it will carry two side reactions the first one will produce Methane and Ethylene, and the second is considered as a Hydrogenation reaction which will utilize the produced Ethylene and Hydrogen to produce Ethane.

The principle of mass conservation which states that raw materials could be converted to any products but with same quantity is applied to construct an overall mass balance for the whole process and for each equipment. In addition, the first law of thermodynamics which states that energy is conserved is applied in order to construct an overall energy balance for all the process.

Simulation is an effective method to find all possible errors or any mishap in the process. It gives a general idea about each equipment elaborating the appropriate conditions. Aspen HYSYS is a convenient application that provides modeling of the process along with major stream and equipment data such as temperature and pressure, and more importantly help to obtain the mass and energy balance for all utilities. Aspen HYSYS gives us the advantage of comparing the obtained results with the individual calculation as classified in the literature. The utilized version of the application is Aspen V11.

For the economy section, an overall study is performed following a strategy that under goes several steps. First, the CAPCOST was utilized to obtain the value of the capital cost, providing the bare module cost of all equipment. Secondly, the contingency, fee, and auxiliary facility costs were taken in account via the calculation of the total module and the grassroots costs. Moreover, the cost of manufacturing (MOC) was obtained by calculating operating labor, waste treatment, raw material, and the fixed capital investment cost. The costs were adjusted using 2022 chemical engineering plant cost index (CEPCI). Also, Heat integration is performed in order to maximize the process heat efficiency and minimize the costs through pinch analysis. The thermodynamics fundamentals applied to ensure the most profitable utilization of the heat of the process. Among any other methods, pinch analysis has been considered to be the best approach to accomplish heat integration.

In this project, the concentration will be on the production of Propylene via Propane Dehydrogenation. The plant’s target is to produce (0.4 – 0.455) million tons per year, considering selectivity above 80% and purity more than 99.5 %. Material and energy balance, simulation and economic scale studies are to be taken in account in order to guarantee a profitable plant.