Experimental Research Of Microwave Pyrolysis About Sludge And Algae Biomass

With China’s economic development and the increase of urban population,environmental contamination and energy shortage have become to two importantproblems. Sludge is the accessory and extremely complex non-homogeneous bodyafter sewage treatment, which is composed of bacterial cell, inorganic particles,organic debris, colloid and so on. As the ratio of sewage water treatment in ourcountry increases year after year, sludge’s volume brought by the sewage treatmentprocess grows larger, thus brings the pollution problem is very serious, how toproperly dispose sewage sludge and promote the utilization of sludge, make ittranslate into energy and material science which has become a major deeply concernproblem about environmental protection. In addition, most of current biofuels comefrom plant, the study showed that these plant fuels have some problems such as thetransformation requires high energy and its supply in short, so find a kind of stablebiological fuel source whose products are high energy and easly translate, sustainableand meet the large demand are very necessary. People develop and use algae forpreparing biological oil fuel, because algae has unique advantages about fast growthand contenting high oil, so algae is a very good biofuels source.Microwave heating technology is widely used because of its unique advantagesabout speedly, uniformity and easy to operate. This paper used the microwave energyradiation on sludge’s and algae’s cracking, sludge’s reduction, harmlessness, resourcesand pyrolysis algae to product bio-oil is study main line. Mainly discussed sludge’sand algae’s microwave cracking of effectiveness the influence law on differentmicrowave reaction time, microwave powers, the amount of experimental materials,microwave absorbers,CO₂andN₂atmosphere.When made microwave pyrolysis experiment on paper mill sludge, the effects ofvarious different factors on paper mill sludge’s microwave pyrolysis and paper millsludge’s physical and chemical changes were mainly discussed. The results showedthat the mass of the paper mill sludge reduced very rapidly within the first6min andthen flattened out with the microwave reaction time increasing; After researched microwave power of900W and1800W, it showed that the greater the microwavepower was, the faster the sludge’s pyrolysis and the more the smell and concentrationof diesel smoke was; The pyrolysis performance was better when the dosage of thepaper mill sludge was increased and of5%NaOH was added as microwaveabsorbers; After adding of5%Activated carbon,5%NaOH,5%H3PO4and5%ZnCl₂as microwave absorbers, experimental results showed that underCO₂atmosphere, the pyrolysis performance was the best when of5%NaOH was added,while underN₂atmosphere, the pyrolysis performance was the best when of5%ZnCl₂was added.When used microwave heating technology to make microwave pyrolysisexperiment on city sludge, mainly discussed at the1800W microwave power, citysludge’s microwave cracking of effectiveness the influence law after adding differentmicrowave absorbers into250g of city sludge under the same atmosphere andaccessing two different atmospheres ofCO₂andN₂in the same premise condition.Study found that: microwave absorbers can very obviously improve city sludge’smicrowave cracking of effectiveness no matter whether adding water into the citysludge. City sludge’s microwave cracking of effectiveness is changing to betterobviously after adding of5%Water, so water is also a good kind of microwaveabsorbers; UnderCO₂atmosphere, city sludge’s microwave cracking ofeffectiveness is changing to better obviously after adding of5%Water、ActivatedCarbon、NaOH andZnCl2into city sludge, it can see that city sludge’s microwavecracking of effectiveness is the best after adding of5%NaOH and it’s temperaturewas331℃at the end of microwave reaction; In the same premise condition, citysludge’s microwave cracking of effectiveness is obviously different when accessingdifferent atmosphere into the city sludge: when adding no microwave absorber, thecity sludge’s temperature was85℃, not even was100℃at the end of microwavereaction underCO₂atmosphere, city sludge’s microwave cracking of effectiveness is better underN2atmosphere, while city sludge’s microwave cracking ofeffectiveness is better underCO2atmosphere when adding of5%Water andNaOH into the city sludge. At the same time, by comparing it can be seen thatalthough reaction atmosphere has certain effect on the city sludge’s microwavepyrolysis, this effection is lower than microwave absorbers make the effect on citysludge’s microwave pyrolysis.Used microwave heating on algae to make it microwave pyrolysis, the effects ofvarious different factors on algae’s microwave pyrolysis and algae’s physical andchemical changes were mainly discussed. Study found that: algae is a kind of weaklyabsorbing object about microwave energy, there are only preheating and dryingprocesses during prue algae’s microwave pyrolysis, algae’s temperature rapidly risedto the boiling point during the preheating process, while rised very slowly during thedrying process and it didn’t place pyrolysis process until the end of the experiment.Algae’s moisture size makes large effection on algae’s internal thermal uniformity.Study showed that algae’s microwave cracking of effectiveness is best when itsmoisture size is about40%;N2atmosphere is more suitable for algae’s microwavepyrolysis, although algae’s microwave pyrolysis processes are very similar underN2andCO2atmosphere, algale’s temperature and weight loss are higher at the end ofthe experiment underN2atmosphere; It showed that the greater the microwavepower was, the better algae’s microwave cracking of effectiveness was, themicrowave power of1800W is more suitable for algae’s microwave pyrolysis whenits volume is not very lager; After adding many different microwave absorbers intoalgae, it showed that algae’s microwave cracking of effectiveness was best whenadding of5%H3PO4, algae’s temperature was about190℃and well generated thepyrolysis oil at the end of the experiment. So considering heating rate and cleavageeffection,H3PO4is a kind of suitable microwave absorber.It can be sure that biomass’ microwave heating has many unique advantages than conventional heating after the series research about microwave pyrolysis experiment,these research results can provide a scientific basis and have a certain instructionsignificance for sludge’s and algae’s microwave pyrolysis. Use microwave heatingcan provide a new effective way about sludge’s reduction, harmlessness, resourcesand pyrolysis algae to product bio-oil.