Co-pyrolysis of heavy oil and low density polyethylene in the presence of supercritical water: The suppression of coke formation

A Review of Laboratory-Scale Research on Upgrading Heavy Oil in Supercritical Water

“…To date, a great deal of progress has been made in upgrading heavy oils (such as oil sand [28,29], oil shale [30,31], Bitumen [26,32,33], residues [34], and heavy oil [35]) in SCW. To understand the current status of upgrading heavy oil in SCW, a timely sorting and summary of the progress made for the processes of heavy oil upgrading in SCW are necessary.…”

“…Thus, more saturates, aromatics, and resins, but less asphaltene, were formed at a higher density. Tan et al [35] reported that the extension of reaction time (from 30 to 60 min) had little effect on the yields of saturates, aromatics, resins, and asphaltenes at the ratio of heavy oil to PE of 10 (wt); whereas the changes of the PE loading amount had a significant effect on the products yields. With the loading amounts of PE increasing from 0.5 to 2.5 g (corresponding to the ratio of heavy oil to PE being 40 to 8), the yield of aromatic and maltene increased from 36.5 wt %, 65.2 wt % to 42.9 wt %, 74.7 wt %, respectively.…”

Catalytic supercritical water gasification of plastics with supported RuO2: A potential solution to hydrocarbons–water pollution problem

“…Figure 2a shows clearly that yields of the gas components changed dramatically between the non-catalytic and catalytic tests as well as among the catalytic tests. In the non-catalytic tests, C2-C4 hydrocarbon gases dominated the gas products as a result of thermal pyrolysis of the plastic [4][5][20][21]. Similar yields of hydrocarbon gases are obtained from conventional pyrolysis of LDPE [22].…”

“…In addition, the much higher HGE obtained from the conversion of PS compared to LDPE would confirm that the aromatic ring in PS was more inclined to redox steam reforming (partial oxidation) to CO by RuO2 than its conversion to pyrolytic gases. PS is known to produce very little hydrocarbon gases and a wide range of aromatic compounds during pyrolysis [5]. On the contrary, the aliphatic polymers would undergo initial pyrolysis to produce both gaseous and liquid hydrocarbons of various carbon chain lengths, which could then be partially oxidized to CO and also would be more prone to hydrogenolysis of C-C bonds to produce methane.…”

“…However they can also be applied to 'dry' feedstocks because during supercritical water processes, water acts as medium as well as a reactant [1][2]. This presents the possibly of applying SCWT to 'dry' feedstocks such as plastics wastes [3][4][5][6]. Supercritical water is completely miscible with common gases.…”