#是天然气好还是焦炉气好? #
This question is not rigorous, "good", what exactly does it mean? Because there are many definitions of natural gas, natural gas refers to all gases that naturally exist in nature, including gases formed by various natural processes in the atmosphere, hydrosphere, and lithosphere. The definition of "natural gas" has long been a narrow definition from an energy perspective, which refers to a mixture of hydrocarbon and non-hydrocarbon gases naturally deposited in the formation. In petroleum geology, it usually refers to oilfield gas and gas field gas. Its composition is mainly hydrocarbons, and contains non-hydrocarbon gases.
Coke oven gas, blast furnace gas and water gas are all a by-product.
Coke oven gas, also known as coke oven gas, because of the combustible components, belongs to high calorific value gas, crude gas or waste gas, refers to the use of several kinds of bituminous coal formulated into coking coal, in the coke oven after high temperature dry distillation, in the production of coke and tar products at the same time produced a flammable gas, is a by-product of the coking industry. The mixture after removing water vapor and various impurities in coke oven gas is called dry gas. Dry gas is the main component of coke oven gas, mainly including H2, CH4, CO, CO2, N2, CnHm, O2, etc., as shown in Table 1 for the content of dry gas.
Blast furnace gas is a combustible gas by-product of blast furnace ironmaking production. Its approximate composition is carbon dioxide, carbon monoxide, hydrogen, nitrogen, hydrocarbons and a small amount of sulfur dioxide. Its dust concentration is 10-50 g/cubic meter (standard condition), and the average dust production is 50kg/t (pig iron)-75kg/t (pig iron). The dust particle size is below 500μm, mainly iron, ferrous oxide, alumina, silicon oxide, magnesium oxide and coke powder. This gas containing combustible carbon monoxide is a low calorific value gas fuel, which can be used for the self-consumption gas of metallurgical enterprises, such as heating hot-rolled steel ingots, preheating molten ladles, etc. It can also be supplied to civilian use, and if coke oven gas is added, it is called "mixed gas", which increases the calorific value.
Table 1 Comparison of coke oven gas and blast furnace gas components
The composition table of natural gas, as shown in Table 2
Natural gas is becoming increasingly popular as a clean energy source, many countries have listed LNG as the fuel of choice, and the rate of increase in mainland natural gas production (including unconventional natural gas) is far from meeting the demand for natural gas consumption.
For coking enterprises, coke oven gas to natural gas is undoubtedly a breakthrough road under the pressure of environmental protection and survival. At present, there are two main technologies of coke oven gas to natural gas in mainland China, namely the methanation process represented by "coke oven gas methanation to natural gas" represented by Southwest Chemical Research and Design Institute Co., Ltd. and the separation process represented by "coke oven gas joint purification and separation to produce natural gas" by Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Among them, the methanation process can be further divided into two types: no carbon methanation process and carbon supplement methanation process. Since the volume fraction of methane in coke oven gas is only 23%~27%, the hydrogen will still be surplus by the non-carbon methanation process, and the raw materials cannot be fully and reasonably utilized. The carbon-supplementation methanation process makes full use of various active components in coke oven gas by supplementing the carbon of the raw gas, so that the raw gas is all methanated, which can increase the production of natural gas by about 30%, which is conducive to subsequent gas separation and low-temperature liquefaction, which is an ideal way to convert coke oven gas into natural gas.