Modified Activated Carbon And Its Adsorption Performance On Gas Mixture Containing Hydrogen

With the exhaustion of the fossil energy,while fossil energy increasingly caused serious environment problem in use process, so we are desperately looking for a kind of clean and renewable energy. Because of wide raw material resources, environmental pollution-free, high energy density, hydrogen received abundant attention. Research for hydrogen storage and transportation has become more and more deeply. The technology of treatment on gas mixture containing hydrogen has become very mature for chemical enterprise. However, some special systems need to keep vacuum in reaction process, that is to say, let produced gas mixture containing hydrogen "disappear" in the system. The commonly used methods are:vacuum tank absorption, ejector system and low temperature adsorption system. This article is under the low temperature adsorption system to research on the performance of activated carbon, in order to improve its adsorption performance of hydrogen mixture, and then to relief the trend of the pressure system.This paper is research on plant activated carbon adsorbent, four kinds of modified methods are used on activated carbon. That is, surface oxidation, metal load, reactivation and microwave modification. The functional groups of active carbon content is determined by Boehm titration. The iodine value is used to characterize adsorption performance of activated carbon. FT-IR is used to quantitative characterize functional groups of activated carbon. SEM and EDS is used to characterize microstructure of activated carbon.Oxidation modification concluded that nitrate concentration is the main factors affecting surface oxidation modification. According to the change of iodine value and surface functional groups, it is determined the best modification condition, which is:nitric acid concentration is 0.5 mol/L, reflow temperature is 323 K, reflux time is 4 h. Total surface oxygen containing functional groups is 0.3703 mmol/g, the iodine value is 1327.6 mg/g. And choose the inlet flow rate is 7.0 L/min, the adsorption performance of hydrogen mixture is increased by 14.4%. The dynamic adsorption performance of hydrogen mixture has improved significantly. And found that the larger of inlet flow rate, the greater enhanced of adsorption performance of hydrogen mixture. To doped Cu, Ag, Co and Pd metal on the pretreatment activated carbon. Microstructure of active carbon and load metal is characterized by SEM and EDS. And determined the iodine value with the change of load capacity. Select two samples to determine its adsorption performance in low temperature adsorption bed, found the adsorption performance increases by about 3.4%.Activated carbon was studied reactivation treatment, it is found that:KOH/carbon ratio is 3:1, reactivation temperature is 1073 K, and constant temperature time is 60 min, this method can obtain activated carbon with a higher iodine value. The activated carbon’s adsorption hydrogen mixture dynamic performance at low temperature is measured. The result show that its adsorption performance do not change, so we conclude that we do not need to enlarge surface too much. Then explore the microwave modification conditions of activated carbon. Experiment found that the microwave power is 450 W, time is 90 s can obtain a bigger iodine value.The surface functional groups are relatively rich, and measured its dynamic adsorption at low temperature, found that it is adsorption performance increases by about 2.7%.