System Analyses of High-Value Chemicals and Fuels from a Waste High-Density Polyethylene Refinery. Part 1: Conceptual Design and Techno-Economic Assessment

Abstract

The increasing amount of plastic waste generation has become an important concern for the chemical industry and government agencies due to high disposal and environmental leakage rates. Chemical recycling is a promising technology due to the potential reduction of pollutant emissions and the establishment of a circular economy through the production of monomers and fuels. However, there is scarce information on industrial scale processes of this technology and their energetic, economic, and environmental performance. Therefore, the present process modeling study presents a novel multiproduct pyrolysis-based refinery for the conversion of 500 tonnes/day of waste high-density polyethylene (HDPE). The products obtained from the modeled refinery were chemical grade ethylene and propylene, an aromatics mixture, and low-and high-molecular weight hydrocarbon mixtures (MWHCs). Part 1 of this study focuses on the energetic and economic evaluation of the refinery and the potential effects of heat integration. The energy efficiency was 68% and 73% for the base case and the heat integrated refinery, respectively. The net present values (NPVs) were 367 and 383 million U.S. dollars (MM USD), for the base case and the heat integrated process, respectively. These results suggest energetic and economic sustainability of the design and its promising application on an industrial scale.

Waste respirator processing system for public health protection and climate change mitigation under COVID-19 pandemic: Novel process design and energy, environmental, and techno-economic perspectives

“…For the other unit processes of separating or processing products from waste respirators, we use the Peng-Robinson thermodynamic package to perform the process simulation due to its wide application in relevant literature [25] , [43] . Aspen HYSYS is used for performing the process simulation for the CO 2 separation section because of the completeness of the thermodynamic parameters for the MEA absorption process [63] .…”

“…The exponential factor ( scf and scft ) is referred from the relevant literature [42] , [73] , [74] , [75] , [76] . The indirect capital cost ( IC ) and land cost ( LC ) are estimated by 123% and 6% of total equipment procurement cost ( TPEC ) [43] , respectively. The working capital cost ( WC ) is estimated by 5% of the summation of land cost and total equipment installation cost.…”

“…(6) , (7) , (8) , respectively. DPC denotes the depreciation cost, and the values of parameters ptici , geci , and txr are 0.02, 0.1, and 0.35, respectively, which come from relevant literature [43] , [44] . …”

“…Products are sent to the cyclone to separate the char, which is fed into the onsite combustion section to provide high-temperature heating energy. Gaseous products are then cooled to 200 °C and sent to the pressure swing absorption (PSA) unit, which is modeled as a separator in the process simulation, to separate nitrogen [42] , [43] , while the rest of the products are cooled, compressed, and split into two streams with light and heavy chemical components. The lighter stream is then sent to the light component separation section, while the heavier stream is directly fed into “C4 and C5 Separator” in the light component separation.…”

“…To convert the byproducts of butene in the overhead stream from C4 and C5 separator into butane, direct hydrogenation is considered in this section. In this hydrogenation process, the overhead stream is treated by the preheated hydrogen and NiMo catalyst in the hydrogenator (150 °C, 1.01 bar) [43] , which is modeled as stoichiometry reactor (RStoic). The product stream is cooled, pressurized, and sent to product separator (81 °C, 8 bar), where the butane mixture is split in the overhead stream under 37.60 °C.…”