Characterization of Working Thicknesses of Some Bath-Dip-Produced Corrosion – Protective Bitumen Coatings on Polish-Prepared Low Carbon Steel Specimens
The coating thickness is an important variable that plays a role in product quality, process control and cost. Determination of the required working thicknesses for different service requirements is however a complicated task in the product finishing field. A previous study has shown that Nigeria is blessed with abundant bitumen resources for sustained exploitation as common, economical and effective coat-inhibitors of steelwork corrosion in her economy. This paper presents a testdetermination of the expected range of working thicknesses of coatings with proper bitumens from the resources. Bitumen samples were harvested at three different critical bitumen resource sites in the country for the tests. 30 specimens of the steel were properly prepared. Coatings of different thicknesses were produced on the specimens by dipping a different pair of them in each bitumen sample heated to each of five different temperatures in the range of 170 – 230 O C and removing and cooling them to 38 O C-room-temperature. The thickness of each produced coating was properly determined with a micrometer through dimensional change before and after coating. Analysis of the overall obtained data shows that the average working thicknesses of coatings with any bitumens of comparable quality to the as-harvested from the resources using temperatures in the range will decrease with increase in temperature from about 1.46 to 0.81mm respectively, and thicknesses of coatings with the separate bitumens using the same bath temperature will have minimal variations.
Assessment of Physicochemical Properties of some Bitumens from Nigerian Resources
Bitumen is a cheap, common, and important material in today’s technological world. Bitumens gotten at different locations on earth, and produced from different manufacturing processes, or crude feedstocks can however have wide variations in physico-chemical properties and levels of service performances. Hence reliability, handling, and modification in technological usage of different bitumens demands that proper information on a given harvested one should be consulted. Nigeria has large reserves of natural bitumen resources and potentials for sustained production of bitumen in large quantity, but basic applicable public information is lacking on bitumens at most locations of the resources. In this paper, proper test-obtained result of the properties is presented for three bitumen samples obtained from some important sources in the country. Assessment of the results vis-a-vis available information on bitumens elsewhere indicate that any clear surface or underground natural bitumen obtainable in the region of Agbabu village in Ondo State, and a manufactured type from Kaduna Refining and Petrochemical Company (KRPC) in the country are comparable with bitumens of good or acceptable qualities from other locations in the world. Bitumen from the region and the as-manufactured are therefore recommended to be producing in large available quantity and exploiting for different technological applications.
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.