Technical Evaluation of Selexol-Based CO2 Capture Process for a Cement Plant.

Cement industry accounts for the second largest emitter of anthropogenic greenhouse gas in the globe with 900 kg CO2 emitted into the atmosphere from producing one tonne of cement. Hence, the effort made to mitigate this issue seems not productive , which gives rise to the design of the carbon capture and sequestration [CCS] process which is one of the few ways obtained to greatly reduce CO2 production from the cement plant. The research work assessed the technology used for the cement plant by employing an old cement plant with post-combustion CO2 capture using physical solvent (Selexol). The Aspen Hysys simulation results show that the process can capture 97% of the CO2 and lean loading of 0.37. The Ashaka Cement Plant operates at maximum capacity of approx. 1 million tonnes cement /year with CO2 released at about 500,000 tonnes per year. The capture unit was able to reduce the CO2 released into the atmosphere from 4.86% to 0.13%. The overall result of the analysis shows that selexol has proven to be thermally and chemically stable under the operating conditions used. It is recommended that, the simulation results should be retrofitted into the Ashaka cement plant, in order to determine the best CO2 capture efficiency, performance which results to the choice of this capture technology.

Greenhouse Gas Emission Determinants in Nigeria: Implications for Trade, Climate Change Mitigation and Adaptation Policies.

This study investigated and analyzed the determinants of Carbon Dioxide (CO2) emission in Nigeria. The study relied on secondary data from World Bank and Central Bank of Nigeria covering 40 years (1970-2009). The data were analyzed using Zellner’s Seemingly Unrelated Regression (SURE) model. The results of the analysis show that fossil energy demand or consumption, rents from forestry trade, agricultural land area expansion and farm technology were significant determinants of greenhouse gas (GHG) emission in the study area. On the other hand, the second equation indicated that fossil fuel energy demand was exogenously determined by economic growth rate (proxied by GDP growth rate) and farm technology applied in the country. It was recommended that Nigeria should put in place policies that will tax companies or firms emitting GHGs and utilize such tax proceeds for research and building the capacities of farmers to adapt to deleterious effect of climate change in the country and continent. The development of existing and new technologies for adapting to climate change and variability, building of environmental consciousness of Nigerians through curriculum restructuring and provision of weather information services by the Nigerian governments and their agencies to enable farmers plan against weather uncertainty and risks were also recommended.

A Preliminary Estimation on Carbon Footprint of Raw Water from the Reservoirs for Domestic Use in Taiwan.

This study aims to evaluate the carbon footprint of raw water from reservoirs for domestic use in Taiwan. It also provides a preliminary measure and reference database for greenhouse gas (GHG) emission of reservoir systems in Taiwan. Four reservoirs, Feitsui (F.T.) and Liyutan (L.Y.T.) in subtropical zone and Nanhua (N.H.) and Tsengwen (T.W.) in tropical zone, were selected as the cases to be examined for carbon footprint inventory, including the GHG emission from the water body and from human activities. Carbon footprint inventory followed PAS 2050 (2011 Specification for the assessment of the life cycle greenhouse gas emissions of goods and services). GHG emission from water body followed the instruction of UNESCO guidelines. The boundary of this inventory covers the water intake works, impoundment region, the dam, the affiliated hydroelectricity power plant, the administration center and other facilities. In this study, the floating chambers with gas chromatography (GC) were chosen to measure the GHG flux from the water body. For the emission of CH4 and N2O from the water body, there are no significantly difference between the fluxes during the daytime and nighttime. For carbon dioxide, the instantaneous flux during the nighttime is higher than the daytime flux. The two reservoirs in tropical zone emit more CO2e from the water body than those in subtropical zone. Summarizing the direct and indirect GHG emission, for the four reservoirs, the annual emission quantities ranged from 653 ton of CO2e to 23,146 ton of CO2e. The carbon footprint of water supply for domestic use ranged from 0.002 kg CO2e/m3 to 0.028 kg CO2e/m3. Roughly speaking, the total GHG emission quantity of the 24 main reservoirs in Taiwan was estimated to be around 121,800 ton of CO2e with the total yield of 4.35 billion m3 of water annually using the highest carbon footprint 0.028 kg CO2e/m3.