In order to clarify the mechanism and the effect of mixed-polymer treatment on the reaction rate of hydrothermal cracking in supercritical water, experimental investigation were carried out with mixtures of PE, PP and/or PS at 430°C and a pressure of ca. 42 MPa. Following results were obtained.(1) When a mixture of different kinds of plastics are treated hydrothermally, the plastics, which are more hardly decomposed, can be easily degraded into low molecular weight oily materials by attack of radicals which are generated from the plastics more easily decomposed.(2) The mechanism of attack of radicals on the plastics, which are more hardly decomposed, in the mixed treatment is effective no matter whether the cracking mechanism of these plastics is random scission or depolymerization at the end of main chain. (3) In mixed treatment, the main mechanism of degradation for each plastic is the same as that in separate treatment, so that the main composition of oily product in mixing treatment is similar to that of the mixture of oily products in each separate treatment. But some new materials were also found in the oily product. They are formed by the reaction of radicals from plastics easily decomposed and the products from plastics hardly decomposed, so that they retain the similar structures of main chain structure of the plastics. (4) In either mixed or separate treatment, the composition of oily product by thermal cracking does not differ much from that by hydrothermal cracking in supercritical water. However, much less polymerization among reactive products occurs in the hydrothermal treatment of mixture.
Microbial EOR MEOR fi eld test 1 4 was carried out in Fuyu oilfi eld, China. In this fi eld test, Enterobacter sp. CJF-002 7 which produced insoluble polymer was injected with nutrient, and oil production increased more than twice in volume because the high permeable zones were plugged with the polymer, and the water channeling was reduced 8, 9 . Our research group carried out experimental studies to analyze the mechanisms of profi le modifi cation by the polymer produced by CJF-002.Firstly, 10m one-dimensional reservoir model was used for analyzing the polymer production behavior of CJF-002. CJF-002 was injected with nutrient and incubated. After the incubation, water was injected to observe the pressure of every 1m-point. As a result, high differential pressure was observed at the section of 0-1m and 3-4m. That is, CJF-002 produced the polymer at these section more actively. Moreover, it was suggested that a mixture of culture solution and brine improved pH of culture solution, and this improvement reactivated the polymer production of CJF-002 at the middle section 3-4m and lower section. Secondly, network model was used for analyzing the effect of the polymer on profi le modifi cation. This model consisted of three 4m-low permeable sand-packs and one 4m-high permeable sand-pack. These sand-packs were reticulately jointed together at every 1m-point. CJF-002 was injected with nutrient from the central inlet and synthetic brine was injected from the other two inlets. Absolute permeability and fl ow rate of each section were calculated from the pressure observed at every jointing point. As a result, CJF-002 produced a signifi cant amount of polymer in all the high permeable hose and the permeability of high permeable hoses decreased to approximately 1/2 of original permeability. Consequently, the fl ow rate of high permeable hoses decreased and that of low permeable hoses increased. It showed that the polymer produced by CJF-002 was effective on the profi le modifi cation.
In order to obtain the basic data in cracking of PE, PP and PS (addition polymerization plastics), experimental investigation was carried out using supercritical water of density of 0.3 g/cm 3 at a temperature of 430°C and a pressure of ca. 42 MPa.It was found that these plastics were easily decomposed to oily materials without coke formation and the time required for liquefaction was in the order of PE>PP>PS. The oily products obtained had the main chemical structure of polymers; normal paraffin's for PE, and 1,3,5-cyclohexane for PP. For PS, styrene monomer was first produced, with a gradual increase in ethyl benzene toluene and stable poly-phenyl hydrocarbons with 2-4 rings, which were different, from oligomer of styrene. The amount of them increased with reaction time. When a decomposition reaction occurred in alkali solution, the decomposition rate decreased, but the reaction mechanism seemed to be unchanged.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.