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1.
污泥连续水热炭化工程系统研究 总被引：2，自引：2，他引：0
水热炭化可以显著改善污泥的脱水性能,促进污泥的无害化、减量化、资源化利用,但目前污泥水热炭化技术的工业化应用鲜有报道。该研究基于工程规模的污泥水热炭化系统开展研究,重点研究了系统工程设计和控制逻辑,开展了系统参数测试,分析了污泥炭、气相和水相的理化性质和组分分布,并在此基础上进行了系统能量平衡分析。结果表明,系统污泥年处理量达1.4×104 t,水热炭化后的三相产物分别为污泥炭28.57%,水相70.00%,气相1.43%,污泥脱水率达75%,综合整个生产系统,系统加热能为454.22 MJ/t,动力耗能为64.80 MJ/t,连续水热炭化工程系统能耗比为83.83%,能量回收率为66.68%,系统具有较高的能耗比。该研究可为生物废弃物连续水热炭化技术的研发和推广应用提供重要的工程依据。 相似文献
2.
水热炭化被认为是极具潜力的安全处置与资源化利用鸡粪的技术措施之一。该研究将鸡粪在190和260℃水热炭化处理不同时间(1、6和12 h),收集并测定固体产物生物质炭特性,目的在于了解水热炭化反应温度和时间对鸡粪生物质炭特性的影响。结果表明,鸡粪经过水热炭化处理后,46%~56%的干物质转化为生物质炭,C、P质量分数分别增加了5%和59%以上,而H、O、N、K质量分数则分别降低了9%~18%、26%~65%、19%~37%和92%~97%。表面电荷量降低,p H值依变性也减弱,其中有效阳离子交换量降低了50%~90%。生物质炭中1~5μm孔隙显著减少,主要形成1和100μm左右的孔隙。总体来看,水热炭化反应温度越高,反应时间越长,这些指标提高或降低的幅度越大,生物质炭的炭化程度越高;比起反应时间,反应温度对生物质炭性质的影响更大。该文还讨论了鸡粪生物质炭作为土壤调理剂的应用价值与潜力,研究结果可为鸡粪生物质炭在土壤改良等方面的应用提供基础数据。 相似文献
3.
水热生物炭燃烧特性与动力学分析 总被引：4，自引：4，他引：0
采用热重法对锯末、玉米秸秆水热生物炭燃烧特性及动力学进行了研究,考察了不同升温速率(10、20、40℃/min)对燃烧特性的影响,分析了它们的燃烧特性及动力学参数。结果表明:1)水热炭化前后生物质燃烧质量损失集中在挥发分和固定碳燃烧阶段,升温速率快,着火温度、燃尽温度高,整体向高温区转移,综合燃烧特性指数越大;2)40℃/min时,锯末水热生物炭综合燃烧特性指数远大于玉米秸秆,在其余升温速率下区别不明显;3)以20℃/min相同升温速率时,锯末、玉米秸秆水热生物综合炭燃烧特性相对于未炭化生物质下降27%、13%;4)采用一级反应动力学模型和积分法对水热生物炭燃烧动力学进行了研究,一级反应动力学能很好的描述2种生物炭的燃烧动力学,相关系数(R2)均高于0.9,挥发分阶段活化能大于固定碳阶段的活化能。研究结果可为水热生物炭的燃烧应用能提供理论指导。 相似文献
4.
水热梯度变化及不同施肥措施对东北地区土壤有机碳、氮影响 总被引：3，自引：1，他引：3
基于样区的野外观察、土壤实测数据和20年气象资料的统计,分析了东北样区内土壤有机碳含量、储量和土壤全氮含量的空间分布格局及其与年均温(t)、降雨量(p)、有效积温(s)和降雨量/年均温p/t之间的关系.分析了相同水热条件下长期施肥措施对土壤有机碳含量和土壤全氮含量的影响,以及不同水热条件下相同施肥措施间的差异.结果表明:样区内土壤有机碳含量、储量和土壤全氮沿纬度呈现出南低北高的分布趋势;有机碳含量、有机碳储量与气候因素之间存在良好的相关性,土壤全氮含量与p/t间存在良好的相关性.长期施肥处理表明,在相同水热条件下外源有机肥的加入,以及合理施肥都能提高土壤碳含量;相同施肥处理土壤有机碳、氮在不同水热梯度条件下差异显著. 相似文献
5.
鸡粪发酵液培养的小球藻水热液化制备生物原油及其特性 总被引：2，自引：2，他引：0
为探索沼液资源再利用,以鸡粪沼气发酵液培养的小球藻为原料,采用水热液化技术制备生物原油。采取正交试验,在温度250~330℃、时间30~90 min及含固量15%~25%下,探讨了水热反应后各相产物特性及元素回收效率。生物原油产率为13.23%~23.83%,最高产油率在330℃、60 min、15%时取得。生物原油中碳、氢及氮回收率分别是16.13%~31.14%、19.18%~34.89%及5.97%~14.32%,最高碳回收率及最低氮回收率分别在330℃、60 min、15%及250℃、30 min、15%时获得。水热液化各相产物中,碳、氢及氮回收率在水相中占主导地位,分别为48.74%~60.43%、46.81%~62.13%及74.84%~82.67%。热重分析暗示生物原油可能适合制备润滑油。此外,GC-MS分析表明生物原油中烃类物质质量分数为16.14%~24.91%,主要为低碳链烃类,如甲苯及二氢茚等。 相似文献
6.
大量、集中的畜禽粪便,若不加以合理处理利用极易引发严重的环境污染问题。该文选择了集约化程度较高的生猪、奶牛、肉牛、肉鸡和蛋鸡5种畜禽的粪便作为样本,研究了水热碳化温度对畜禽粪便水热处理的影响,通过元素分析、工业分析和热重试验,分析了水热炭的燃烧特性,并比较了不同畜禽粪便水热炭之间的差异。研究发现,水热碳化能够提高水热炭的碳元素、固定碳含量,提高高位热值,降低氢碳比、氧碳比和挥发分固定碳比的值,得到的水热炭类似于褐煤。热重试验发现,水热碳化能够减小不同畜禽粪便样品之间的性质差异。水热碳化温度为180和210℃时,除肉鸡粪便水热炭外,其他畜禽粪便水热炭的综合燃烧特性指数均得到提高,5种畜禽粪便中,奶牛和肉牛粪便水热炭具有更好的燃烧特性。 相似文献
7.
[目的]揭示污泥堆肥施用后土壤单位有机碳矿化及温度敏感性(Q10)对于市政污泥资源化利用和土壤碳库稳定性的主控因素,并进而为市政污泥处理及土壤有机碳固持提供理论支撑。[方法]以黄土丘陵区退化草地土壤为研究对象,测定了不同污泥堆肥添加比例(0,2.0%,5.0%,10.0%,15.0%,20.0%)和培养温度(15℃,25℃和35℃)下土壤有机碳矿化速率,探讨了污泥堆肥添加对土壤有机碳矿化特征和Q10的影响。[结果](1)与CK相比,不同污泥堆肥添加在培养初期土壤单位有机碳矿化速率显著增加(p<0.01),之后迅速下降直至趋于稳定;而施用污泥处理组的土壤单位累积矿化量是CK的1.6～4.2倍,在施用比例达到10.0%～20.0%时其有机碳矿化速率与累积矿化量均差异不显著。(2)运用一级动力学方程,拟合不同温度不同污泥添加土壤单位有机碳矿化动态均达到较好效果(R2>0.95),潜在矿化势(C0)值在6.92～39.60 mg C/g差异显著(p<0.05),土壤有机碳矿化速率常数(k)... 相似文献
8.
炭化温度和时间与棉杆炭特性及元素组成的相关关系 总被引：13，自引：5，他引：8
为了揭示炭化温度和时间对生物质炭特性及元素组成的影响,以棉花秸秆为生物质炭制作原料,对比研究不同炭化温度（300、450、600℃）和时间（0.5、1、2、4、6 h）制备的棉秆炭的pH值、阳离子交换量（CEC）、电导率等特性及有机碳、氮和矿质元素含量及其间的相互关系。结果表明：棉秆炭化出炭率、棉秆炭有机碳含量随炭化温度的升高和时间的延长而降低（出炭率： 48.66%（300℃）>35.39%（450℃）>31.06%（600℃）,有机碳：564.02 g/kg（300℃）>405.94 g/kg（450℃）>259.36 g/kg（600℃）;在300℃下,pH值随着时间的延长而增大,450℃和600℃下基本保持在10.5左右;电导率随炭化温度的升高而增加,在炭化时间内变化不明显,且炭化温度300～450℃对棉秆炭的电导率影响相对较小,600℃影响较大;CEC随炭化温度的升高而降低,在300℃下随炭化时间的延长而增大,450和600℃下则降低。棉秆炭中全磷,全钾,速效钾,钙,镁含量随着温度的升高和时间的延长逐渐增加,全氮和碱解氮则相反,速效磷含量则表现出90.07 mg/kg（450℃）>60.72 mg/kg（600℃）>20.18 mg/kg（300℃）的变化趋势。炭化温度和时间与棉秆炭指标间相关分析表明,炭化温度和时间与出炭率、CEC、有机碳、全氮和碱解氮间呈负相关,与pH值、全磷、全钾、速效磷、速效钾、钙和镁含量呈正相关。综合分析,低温短时间（300℃,1～2h）制备的棉秆炭对农业利用预期效应较好,该研究结论为新疆棉秆炭的制备和农业利用提供理论依据和数据支撑。 相似文献
9.
《土壤与作物》2015,(1)
近些年土壤固碳研究受到广泛关注。在诸多影响土壤固碳的因素中,团聚体结构对土壤有机碳的物理保护机制是研究的焦点。土壤中原始有机碳在土壤团聚体和团聚体结构形成中发挥着不可替代的作用,土地利用方式、耕作方式以及施肥措施发生变化后,团聚体及其结构在土壤有机碳固定中的作用变得更加凸显。团聚体结构包含众多的孔隙,这些孔隙的大小、数量、形状以及空间分布等都会影响土壤中水分运移、植物根系生长、土壤生物活动以及土壤有机碳分配,它们相互作用影响土壤中有机碳的固定。本文分析了水分、植物根系以及土壤生物与团聚体孔隙结构之间的关系,阐述了这些因素在土壤有机碳变化中所起的作用,并对目前研究的不足进行了概述。同时,阐述了不同CT(Computed Tomography,CT)技术在土壤团聚体结构探测中的应用及其对结构数据的提取方法,探讨了团聚体孔隙结构对有机碳固定的影响,展望了团聚体结构对有机碳固定影响需要加强的研究内容。参66。 相似文献
10.
为了探究预处理下西瓜皮微波水热(microwavehydrothermal,MHT)温度对炭化产物资源化的影响,该研究对其干燥处理、酸处理和碱处理后进行不同MHT温度试验,分析炭化产物的特性及其可能的应用。结果表明,在MHT温度为130～190℃之间,碱处理在MHT温度为170℃所得水热炭的产率最高达86.01%,明显高于干燥处理和酸处理对应产率(P0.05)。然而,其热值小于17 MJ/kg,不具有作为燃料的潜力。干燥处理和酸处理不仅能获得符合标煤的水热炭,而且能够得到高附加值的5-羟甲基糠醛(5-hydroxymethylfurfural,HMF)和糠醛(furfural,FF)。对比干燥处理产物情况,酸处理能够在MHT温度为130℃时得到3.3%的HMF产率以及在150℃下得到相同产率的FF。经济性分析表明在MHT温度为130℃下酸处理1 t新鲜西瓜皮可得炭化产物的价值约为6 607元,且工艺能耗仅为66元/t。该研究结果可为预处理下西瓜皮资源化转化以及MHT工艺的实际应用提供参考。 相似文献
11.
铵、钾同时存在时, 土壤对铵的优先吸附 总被引：3，自引：0，他引：3
Ten soils collected from different parts of China were used in a series of experiments to study fixation of NH4^ and K^ by soils.When K^ was added concurrently with or prior to NH4^ ,the soils were found to fix more moles of NH4^ than those of K^ ,irrespective of the mole ratios of NH4^ to ^ that were added. 相似文献
12.
共生固氮在农牧业上的作用及影响因素研究进展 总被引：5，自引：1，他引：5
共生固N是生物固N的主体部分,具有固N效率高、应用范围广等特点。叙述了主要豆科作物年固N量及固N量占豆科作物本身所吸收N的比例,阐述了豆科作物在与非豆科作物间套轮作中固定N素的转移及对非豆科作物的影响,并介绍了影响豆科作物-根瘤菌共生体共生固N效率的主要因素。开展豆科作物-根瘤菌共生体系方面的研究对农业可持续发展具有重要意义。 相似文献
13.
以辽河实际水文资料为基础,在沈阳农业大学水利学院综合试验场内,模拟不同流速水流冲击作用下沉坠式生态浮岛固定方式的稳定特征.结果表明:制作合理的浮岛模型,要始终保持浮岛在水面漂浮,同时减低浮岛在水中的重心；根据不同水流情况,应适当调整浮岛之间的距离,以免发生浮岛相互碰撞,水流速度越大,浮岛之间的距离就越大.研究结果对辽河生态浮岛的布设有着重要的意义. 相似文献
14.
《Communications in Soil Science and Plant Analysis》2012,43(14):1583-1591
Abstract During the period 1977–1979, NaNO3, urea, and urea plus 2% (wt/wt) nitrapyrin (2‐chloro‐6‐(trimethyl)pyridine) were compared on a Matapeake silt loam (fine silty mixed mesic Typic Hapludult) . Nitrogen sources were injected as solutions into the water system at 224 kg N ha‐1yr‐1used for subsurface trickle irrigation of corn (Zea maysL.). Nitrogen was withheld in 1980 in order to assess residual N effects. Grain yields in 1980 for the NaNO3, urea, and urea plus Nitrapyrin treatments were 5.10, 4.56 and 6.52 Mg ha‐1, respectively. Corresponding ear leaf N concentrations were 17.7, 16.7 and 19.2 g kg‐1. Significantly higher grain yield and leaf N concentrations associated with the use of nitrapyrin as a nitrification inhibitor indicated greater soil N reserves for this treatment. Non‐exchangeable (fixed) NH4 +, in soil cores taken in November 1981 averaged 54, 59 and 74 ug N g‐1for the respective N regimes. The concentration of fixed NH4 +increased with sampling depth, averaging 54, 61 and 72 ug N g‐1for the 0–5, 30–35, and 60–65 cm profile depths, respectively. This trend is ascribed to increasing quantities of micaceous and vermiculitic clay (<2 um) with increasing profile depth. 相似文献
15.
Soil stability, nitrogen and carbon fixation were assessed for eight biological soil crust community types within a Mojave Desert wilderness site. Cyanolichen crust outperformed all other crusts in multi-functionality whereas incipient crust had the poorest performance. A finely divided classification of biological soil crust communities improves estimation of ecosystem function and strengthens the accuracy of landscape-scale assessments. 相似文献
16.
Ammonium fixation and adsorption experiments were conducted to study the effect of potassium on ammonium fixation into interlasyer of vermiculite and ammonium adsorption at the surface of vermiculite both in the binary (NH4^ -Ca^2 ) and ternary (NH4^ -Ca^2 ) ystems.In the ammonium fixation experiment,5 mmol NH4^ kg^-1 was added alone,or after,before of simultaneously with 5 mmol K^ kg^-1 to the vermiculite (Vermiculite:solution=1:1),and the incubation was conducted for 3 days under constant 20℃，In the adsorption experiment ,after addition of 10 mmol Ca^2 L^-1 as matrix ions ,either,NH4^ alone with a concentration series from 0.1 to 5.0 mmol NH4^ L^-1(binary exchange system of NH4^ and Ca^2 )of NH4^ together with 5 mmol K^ L^-1(ternary exchange system of NH4^ ,K^ and Ca^2 ) was added to vermiculte at a vermiculite to solution ratio of 1:10 for 24-h equlibrium.The results of the fixtion experiment showed that the presence of K^ increased NH4^ fixation for all the treatments,regardless of the addition orders.For ammonium adsorption a linear realtionship between activtiy ratios of NH4^ to Ca^2 and Mg^2 in the equilibrium solutions(ARNH4)and incereases of exchangeable NH4^ at the surface of vermiculite after 24 h equilibrium (△Ex-NH4^ )was shown for almost the whole concentration ranges tested.Compared With the binary system ,the slope of the curve of the ternary system was steeper,indicaitng a more intensive adsorption of NH4^ in the presence of K^ ,It was demonstrated that K^ did not reduce the ammonium fixation into the interlayer and ammonium adsorption at the surface of vermiculite ,which indicated that, under the experimental conditions of this study,K^ did neither occupy the sites for NH4^ -fixation in the interlayer nor the sites for NH4^ -adsorption at the surface of vermiculite. 相似文献
17.
本工作研究了分子氢对不同生长条件下三种红萍:细绿萍(Azollsa filiculoides),卡洲萍(Azolla caroniana)和小叶萍(Azolla microphylla)的固氮活性的支持作用,结果表明,在5000—20000lx不同光照强度下,分子氢对红萍固氮活性均有支持作用,当光照强度为10000lx时,10％的分子H_2可使红萍的固氮活性增加30—80％,在5000lx弱光条件下,相同浓度分子氢使红萍固氮活性增加的幅度比10000lx光照时大。在相同的光照条件下,大叶萍的固氮活性较高,分子氢对其固氮活性的支持作用也较强,说明了在萍藻共生体系中,光能利用、固氮效率与分子氢利用效率呈正相关。同时,分子氢对于红萍固氮活性受尿素毒害所致的抑制也有减慢作用。在培养液中尿素浓度超过5ppm时,红萍的固氮活性受到抑制,当尿素浓度达到50ppm时,其固氮活性抑制率达50—60％,但20％的分子氢可使其固氮活性恢复到正常培养下的70％以上。在一定的尿素浓度范围内,红萍固氮活性受抑程度愈大,分子氢对其减慢的作用也愈强。 相似文献
18.
Abu T. M. A. Choudhury Mihály L. Kecskés Ivan R. Kennedy 《Journal of plant nutrition》2014,37(10):1627-1647
The critical nitrogen (N) requirement of rice crops for maximum yields is well known. To overcome acute N deficiency in rice soils as a result of an increasing yield per unit area in the past 50 years of almost three-fold, this element has been usually supplied to the rice crop as the chemical fertilizer ‘urea’. Unfortunately a substantial amount of the urea-N is lost through different mechanisms, causing environmental pollution problems. In principle, utilization of biological nitrogen fixation technology can supplement the use of urea-N, reducing the environmental problems to a considerable extent by improving nitrogen use efficiency. Different biological nitrogen fixation (BNF) systems have different potentials to provide an N supplement. It is necessary to design appropriate strategies to obtain more sustainable N supply to the rice crop. This paper reviews research to evaluate the potential of different BNF systems to supply N for the rice crop, assessing the current information. 相似文献
19.
Prospects and potentials for systems of biological nitrogen fixation in sustainable rice production 总被引：1，自引：0，他引：1
The N requirement of rice crops is well known. To overcome acute N deficiency in rice soils, this element is usually supplied to the rice crop as the commercially available fertilizer urea. But unfortunately a substantial amount of the urea-N is lost through different mechanisms causing environmental pollution problems. Utilization of biological N fixation (BNF) technology can decrease the use of urea-N, reducing the environmental problems to a considerable extent. Different BNF systems have different potentials to provide a N supplement, and it is necessary to design appropriate strategies in order to use BNF systems for efficient N supply to a rice crop. Research has been conducted around the world to evaluate the potential of different BNF systems to supply N to rice crops. This paper reviews salient findings of these works to assess all the current information available. This review indicates that the aquatic biota Cyanobacteria and Azolla can supplement the N requirements of plants, replacing 30–50% of the required urea-N. BNF by some diazotrophic bacteria like Azotobacter, Clostridium, Azospirillum, Herbaspirillum and Burkholderia can substitute for urea-N, while Rhizobium can promote the growth physiology or improve the root morphology of the rice plant. Green manure crops can also fix substantial amounts of atmospheric N. Among the green manure crops, Sesbania rostrata has the highest atmospheric N2-fixing potential, and it has the potential to completely substitute for urea-N in rice cultivation. 相似文献
20.
Potassium (K) release from sources that are not initially exchangeable is attributed to depletion of interlayer K of micas and clay minerals or weathering of feldspars. The aim of the present study was to estimate the K release from interlayer K. Soil samples from 17 field experiments in ley on a range of mineral soils in Norway were used in the study. The change in K‐fixation capacity was used as an estimate of depletion of interlayer K. It was assumed that the increase in K‐fixation capacity during 3 yr of cropping was equivalent to the amount of K depleted from the interlayer positions. Mean K fixation increased in the majority of the soils during 3 yr of grass cropping both with and without K application. The increase in K fixation indicated that without K application, the K uptake from interlayer K amounted to 43%, 28%, and 26% of the K yield for clay soils, high‐K sandy soils, and low‐K sandy soils, respectively. Including K uptake from exchangeable K in the topsoil and from subsoil, the explained K uptake amounted to 79%, 69%, and 81% for the three groups of soil, respectively. Simple linear‐regression analyses showed that the change in K fixation during 3 yr of grass cropping was best explained by the percentage of clay in the soil. 相似文献