Chuanwei Zhuo

Microstructural Analysis of Carbon Nanomaterials Produced from Pyrolysis/Combustion of Styrene-Butadiene-Rubber (SBR)

Styrene-Butadiene-Rubber (SBR) is a synthetic rubber copolymer used to fabricate several products. This study aims to demonstrate the use of SBR as feedstock for carbon nanomaterials (nanofibers and nanotubes) growth, and therefore to establish a novel process for destination of waste products containing SBR. A three stage electrically heated flow reactor was used. Small pellets of rubber were pyrolyzed at a temperature of 1000 °C. The pyrolyzates were mixed with oxygen-containing gases and were burned. The products of combustion were used to synthesize the carbon nanomaterials (CNMs) at the presence of a catalyst. CNMs have a wide range of potential applications due to their extraordinary mechanical, thermal and electrical properties. Produced materials were characterized by SEM and TEM, whereas combustion products were assessed using GC. Results showed that CNMs with outer diameters of 30-100 nm and lengths of about 30 µm were formed. Therefore, it was demonstrated that waste products containing SBR can be used to generate CNMs which are value-added products of intense technological interest.

Pyrolytic Conversion of Biomass Residues to Gaseous Fuels for Electricity Generation

As petroleum resources are finite, it is imperative to use them wisely in energy conversionapplications and, at the same time, develop alternative energy sources. Biomass is one ofthe renewable energy sources that can be used to partially replace fossil fuels. Biomass-based fuels can be produced domestically and can reduce dependency on fuel imports.Due to their abundant supply, and given that to an appreciable extent they can be consid-ered carbon-neutral, their use for power generation is of technological interest. However,whereas biomasses can be directly burned in furnaces, such a conventional direct com-bustion technique is ill-controlled and typically produces considerable amounts ofhealth-hazardous airborne compounds. Thus, an alternative technology for biomass utili-zation is described herein to address increasing energy needs in an environmentally-benign manner. More specifically, a multistep process/device is presented to acceptgranulated or pelletized biomass, and generate an easily-identifiable form of energy as afinal product. To achieve low emissions of products of incomplete combustion, the bio-mass is gasified pyrolytically, mixed with air, ignited and, finally, burned in nominallypremixed low-emission flames. Combustion is thus indirect, since the biomass is notdirectly burned, instead its gaseous pyrolyzates are burned upon mixing with air.Thereby, combustion is well-controlled and can be complete. A demonstration device hasbeen constructed to convert the internal energy of biomass into “clean” thermal energyand, eventually to electricity. [DOI: 10.1115/1.4025286]Keywords: biomass residues, DDGS, King Grass, pyrolytic gasification, combustion

Feasibility Study on Power Generation from Waste Plastics with Partial Precombustion Carbon Capture and Conversion

AbstractThe feasibility of upcycling waste plastics into concurrent production of carbon nanotubes (CNTs) and of a hydrogen-enriched gaseous hydrocarbon stream was shown to be possible in a continuous steady-state steady-flow process. The feedstock was post-consumer (waste) low-density polyethylene (LDPE), which was pyrolyticaly gasified at 800°C, in a flow of nitrogen carrier gas. The evolving gaseous hydrocarbon pyrolyzates were first used as carbon growth agents for CNTs in a reactor, a process that lowered their carbon content and increased their hydrogen content. Thereafter, the unreacted hydrocarbon pyrolyzates and the generated hydrogen were mixed with air and burned. This conversion of solid waste plastics to gaseous fuels allowed thorough mixing with air and, upon ignition, the formation of environmentally benign fuel-lean premixed flames for subsequent power generation purposes. The CNT generation in the reactor took place by chemical vapor deposition (CVD) on untreated stainless steel mesh subs...

Síntese de nanomateriais de carbono a partir do resíduo de milho (DDGS)

The worlds largest ethanol producer (USA) uses corn as feedstock. DDGS (distillers dried grains with solubles) is the main waste generated from this process (around 32 million t/year). DDGS samples were pyrolyzed at 1000 oC in a furnace with controlled atmosphere. The effluent was channeled to a second furnace, in which catalyst substrates were placed. Chromatographic analysis was used to evaluate the gaseous effluents, showing that the catalyst reduced hydrocarbon emissions. The solid products formed were analyzed by SEM and TEM. Graphitic structures and carbon nanofibers, 50 µm in length and with diameters of 80-200 nm, were formed.

ANÁLISE E CONTROLE DOS HIDROCARBONETOS GERADOS NA COMBUSTÃO DOS RESÍDUOS DE PET

Brazilian production of PET (polyethylene terephthalate) in 2010 was of 505,000 tones. The PET waste may be used to generate energy by controlled burning. In this study, emissions of light hydrocarbons generated during combustion of these wastes are characterized. Samples of post-consumer PET bottles were inserted in an electric furnace at temperatures of 600, 800 and 1000°C under an atmosphere of 15% O2 and 85% N2. The effluents were subjected to a SiC filter and channeled into the second furnace at 1000°C. Stainless steel meshes were placed in the second furnace in order to work as catalyst. Gas chromatography is used to evaluate the effluent with and without the catalyst use, wherein is showed a significant reduction in the emissions using the meshes. Results allow a characterization of the hydrocarbons generated during the controlled burning of PET waste providing information for control and recovery of these gases emissions.

Síntese de nanotubos de carbono a partir do bagaço da cana-de-açúcar

The traditional sugar production associated with the growing ethanol production makes the sugarcane industry one of the main segments of the Brazilian economy; together the Brazilian industries of sugar and ethanol processed about 630 million tons of sugarcane in 2009, which generated approximately 142 million tons of bagasse. This work presents an economically and environmentally viable solution for the bagasse disposal through the controlled burn associated with the synthesis of carbon nanotubes (CNTs), materials that have a wide range of potential technological applications due to its exceptional properties. The pyrolysis process at 1000°C associated with a catalyst system were used to recover the generated gases as raw material for the synthesis of CNTs. Gaseous emissions were analyzed by chromatography and the produced materials were characterized with the use of SEM, TEM, TGA and Raman spectroscopy. Results showed that the catalyst application resulted in the reduction of gaseous emissions. Carbon nanotubes with lengths of 10-40 µm and diameters in the range of 20-50 nm were produced.

Waste-to-Energy Conversion by Stepwise Liquefaction, Pyrolysis and “Clean Combustion” of Waste Plastics

As petroleum resources are finite, it is imperative to use them wisely in energy conversion applications. Plastics, a petroleum-based product, are widely used in manufacturing disposable products and have created a solid waste issue. Due to their abundant supply, and given their high energy content, their use for power generation is of technological interest. However, whereas waste plastics have found limited use in incineration, such a conventional direct combustion technique is ill-controlled and produces considerable amounts of health-hazardous airborne compounds. Thus, an alternative technology is proposed herein to further address our increasing energy needs and, at the same time, utilize our waste plastics streams in an environmentally-benign manner. More specifically, a multi-step process/device is proposed to accept post-consumer plastics, of various types and shapes, and generate an easily-identifiable form of energy as a final product. To achieve low emissions of products of incomplete combustion, the plastics are liquefied, pyrolyzed, mixed with air, ignited and, finally, burned forming pre-mixed low-emission flames. Combustion is thus indirect, since the solid polymer is not directly burned, instead its gaseous pyrolyzates are burned upon mixing with air. Thereby, combustion is well-controlled and can be complete. A demonstration device has been constructed to convert the internal energy of plastics into clean thermal energy and, eventually to electricity.Copyright