The Composition Characteristics Of China's Coke Production Process Emissions Of Particulate Matter And Volatile Organic Compounds, Emission Factors And Emissions Are Preliminary Estimates

China has the largest coke production and export in the world, and more than 40% global coke output and more than 60% global coke export are from China. Coke production shares about 13% of the total coal consumption in China, only next to coal-fired power plants in China's coal consumption. Due to backward coking techniques in China, many pollutants directly emit from coking processes, bringing about adverse effects to local environment and human health. Data from National Development and Reform Commission reveal that each year about 20 billion cubic meters coke oven gas directly emit into the atmosphere without being utilized for backward coking techniques in Shanxi province, China. Though emission from coking might share very limited portions in national emission inventories of pollutants, its influence on local or regional environment can not be neglected. Investigation of source profiles, emission factors and emission volumes of pollutants from coke production is of great importance for the control of air pollution in the region influenced by coking exhaust gas. The present study, by analyzing the stack gas, oven-top gas and ambient air inside and near the coking plants in Shanxi province, target on the source profiles, emission factors and total emission volume of pollutants like VOCs, and will obtain preliminary but valuable results for the scientific assessment of coke industry' influence on national and regional environment. Major conclusions are listed as following:Monocyclic aromatic hydrocarbons (MAHs) in waste gas from beehive coking are much higher than those from byproduct recovery battery coking (BRBC). Coking gas also has higher MAHs than emission from coal-fired power plant, biomass burning and motor vehicle. Beehive coking has higher MAH emission in the beginning days, and byproduct recovery battery coking has higher MAH emission during charging and coke pushing.VOCs from coking processes show characteristic compositional patterns compared to those from emission sources like vehicle exhaust, liquefied petroleum gas, natural gas and paints. A major distinction is the relatively high benzene levels. Characteristic ratios related to BTEX (benzene, toluene, ethylbenzene and xylenes) can be used to diagnose source contribution from coke production. Scatter plots and correlation analysis of BTEX indicate that MAHs from BRBC might be originated from high-temperature degradation of coking coal, but MAHs from beehive coking might have other origins than incomplete combustion.The emission factors for dust from beehive coking are 1.21-3.85 kg/ ton coke, obviously higher than those from BRBC (0.14-0.60 kg/ton coke). Preliminary SO₂ emission factors were estimated to be 2-3 kg/ton coke for beehive coking, and1.0-1.69 kg/ton coke for byproduct recovery battery coking, but a few beehive coke oven showed quite high SO2 emission factors. Preliminary estimation found that Dust and SO2 from coking account for about 7.9% and 14.3% of total dust and SO2 emission in Shanxi province.Methane emits mainly via stack gas in coke production, and emission factor was found to be 228.5±56.1g/ton coke, much higher than those of coal and biomass burning in domestic furnace. Although methane emission from byproduct recovery battery coking is estimated to be about 30,000 ton per year and 0.1% of total methane emission in China, it might be second largest source other than coal production in Shanxi province. Meanwhile, about 20 billion cubic meters coke-oven gas is directly discharged per year without being utilized, and related methane emission might be over 1 million tons per year, and should be of great concern.NMHC factors via dust collector and stack gas are 55.83 and 487.16 g/ton coke, and emission factors of ethane, propane, ethyne, propylene, benzene and (m+p)-xylene had emission factors of 14.18, 23.02, 23.96, 11.08, 31.93, 14.00 g/ton coke. Base on the national coke production from byproduct recovery battery coking in 2005, NMHC emission from byproduct recovery battery coking was estimated to be 2.6-5.7x105 ton, less than 1% of national total NMHC emission. In 2005 NMHC emission from coking in Shanxi province was estimated to be 2.4x105 ton, accounting for 5% of the provincial total NMHC emission.