污泥资源化处理技术及成套设备应用

<正>1污泥堆肥处理的必要性目前污泥处理方法主要有填埋、干化、焚烧、厌氧消化和好氧堆肥等。填埋方式因场地限制没有前途,千化、焚烧、厌氧消化方式因投资大运行成本高昂而难以广泛推进。污泥养分含量高,有机质含量48%~75%,每吨千污泥养分含量相当于100kg硫氢,100kg过磷酸钙和16kg硫酸钾。污泥与畜禽粪相比,有机质高出2~3倍,氮磷钾含量高出更多,是制作有机肥的上乘原料。污泥好氧堆肥处理是指污泥在一定的水分、氧气和温度等条件下,通过微生物     

国内典型市政污泥理化特性和干化特性研究

为探索有效的城市生活污水污泥无害化和资源化利用途径,以杭州市6个典型净水厂产生的市政污泥样品为原料,进行基本理化特性分析,并对国内典型的污泥干化设备进行比选,推进污泥干化焚烧技术路线实施.首先,对污泥样品进行工业、元素、热值、重金属含量、pH值和主成分进行分析,并采用热重红外等方法对干化污泥的燃烧特性进行分析.实验结果...     

6种污泥热干化技术概述

污泥因其含水率高、体积较大、化学属性差异明显,因此不利于运输与后续处理,污泥干化减量也成为当今的首要问题。此次采用污泥热干化技术,根据热源不同分为:微波干化技术、热水干化技术、蒸汽干化技术、天然气干化技术、太阳能热泵干化技术、生石灰干化技术。通过上述技术处理,污泥的含水率大大降低,为后续的污泥焚烧或资源化提供了有利条件。同时污泥处理过程中,应根据所在地资源情况,选取适宜热源,进行污泥干化操作。     

城镇污泥干化焚烧处置技术与工艺简介

本文介绍了污泥的基本特性,对直接热干化、间接热干化、直接-间接联合热干化和其它污泥干化技术的工作原理和优缺点进行了比较,重点讨论单独焚烧、电站锅炉掺烧、垃圾焚烧炉掺烧和水泥窑掺烧等污泥焚烧技术的工艺路线、应用情况和技术特点。分析可知,污泥干化焚烧技术类型多样,采用烟气或蒸汽对污泥进行干化都是可行的,干化污泥单独焚烧、电站锅炉掺烧或者水泥窑协同处置等都有成功案例,应根据具体条件选择合适的工艺,其中将污泥干化后利用流化床焚烧炉进行单独焚烧或在电站锅炉上进行掺烧是最具应用前景的技术路线,而污泥输送、高效干化技术与设备开发及厂区臭气治理等是有待进一步研究的问题。     

污泥焚烧能量利用与污染物排放特性研究

利用Aspen Plus软件对污泥半干化焚烧和掺烧发电2种工艺过程进行模拟,探讨了不同工艺下4种污泥的能量利用情况及污染物排放特性.结果表明:半干化焚烧时,4种污泥的干基热值低于11.5MJ/kg时均需补燃辅助燃料,且随着污泥热值的降低,补燃量显著增加;重金属含量高的污泥易造成大气污染,灰渣也难满足利用要求.污泥掺烧发电时,掺烧热值高的污泥对发电效率有利;对于同种污泥,随着污泥能量份额降低,发电效率提高,且污泥能量份额较低时,重金属含量高的污泥也能满足环保要求,适宜的污泥能量份额建议为5%~8%.当污泥热值低、重金属含量高时,建议采用掺烧发电工艺,反之采用半干化焚烧工艺.     

火力电厂污泥干化废水二次风道蒸发过程模拟研究

城市污泥电厂掺烧发电技术是有望实现城市污泥清洁化、资源化利用的新兴技术,近年来受到广泛关注.污泥干化过程产生的废水通常含有大量的污染物,直接排放会带来严重的环境污染问题.为解决污泥干化废水排放问题,文中提出将废水喷入锅炉二次风道的处理技术,希望通过喷嘴将废水雾化为液滴使其在高温二次风中蒸发进入锅炉.在此基础上,文中通过...     

污泥热干化技术适应性分析及未来发展趋势

污泥干化是污泥处理、处置和资源化利用的前提。文章概述了几种常用的污泥热干化技术,并从能耗、安全性、环境友好性、灵活性4个方面分析其适应性。污泥干化在我国起步较晚,通过适应性对比,推荐转盘式干化技术作为污泥热干化的主导工艺,未来仍将以主流干化技术为主导,并不断完善、优化,而新兴的干化技术则是对主流干化技术有效的补充。     

污泥干化混煤燃烧工艺在循环流化床锅炉应用探讨

污泥干化混煤燃烧工艺是利用现有的燃煤锅炉设施,回收锅炉余热进行污泥干化,并将干化污泥与煤掺混燃烧用于供热或发电,实现了污泥的减量化、无害化、资源化利用。文中阐述了污泥混煤燃烧的潜在优势,通过对污泥混煤燃烧工艺进行综合分析比较,认为在循环流化床锅炉进行干化污泥混煤燃烧是一种切实可行的燃烧方式;探讨了污泥干化的原理,提出了可行的利用循环流化床锅炉余热干化污泥的方式;对污泥燃烧特性进行了探讨,并分析了干化污泥混煤燃烧对循环流化床锅炉运行的影响。     

污泥低温冷凝干化机运行效果影响因素和蒸发除湿控制参数

本文介绍了污泥低温冷凝干化机在污水处理厂的应用情况,实践表明,污泥低温冷凝干化设备非常适合厂内污泥减容减量,干化后的污泥颗粒性质稳定热值高.重点分析了干燥除湿效果的影响因素和过程控制参数,对外界气温变化、挤条机卡堵、两器腐蚀、灰尘堵塞问题的影响因素进行分析并提出解决方案,同时结合项目运行工况,对干燥器内温湿度、空气流速和污泥成型比表面积的参数给出控制建议.     

大型燃煤电站锅炉协同处置污泥的试验研究

针对某电厂300 MW燃煤锅炉污泥干化焚烧处置工程,对污泥干化系统及污泥掺烧对煤粉炉的影响展开了试验研究.通过对污泥干化系统的物料能量平衡计算得出圆盘式污泥干化机的热效率为74.96％,重点分析了污泥干化系统各部分的能耗情况;通过对比掺入污泥后混合燃料和设计煤种的各组分特性,分析了污泥掺烧对原煤粉锅炉运行的影响,结果表明,在污泥掺烧比例低于3％时,对煤粉炉的实际运行无明显影响.     

Reduction in nitrogen oxides emissions by MILD combustion of dried sludge

Demands for the thermal treatment of sewage sludge are increasing due to the regulation of its ocean disposal and the desire to recover its potential energy. Because of the high nitrogen content in sewage sludge, one of the concerns about its combustion is a potential increase in NO_x emissions. Although a number of studies have been conducted to reduce NO_x emissions by combustion modifications, very few studies have addressed the combustion of dried sludge. In this study, a combustion technique called moderate or intense low oxygen dilution (MILD) was applied to the combustion of dried sludge with the goal of reducing NO_x emissions. MILD combustion of dried sludge was tested using both our laboratory-scale vertical combustor with internal circulation and our horizontal cyclone combustor with external circulation. Tests were conducted to find suitable operating conditions and to demonstrate the stable MILD combustion of dried sludge. From these tests, fuel and air flow patterns were found to be an important factor in maintaining stable MILD combustion, and the horizontal cyclone combustor demonstrated excellent performance in the reduction of NO_x emissions by the MILD combustion of dried sludge.     

High temperature steam gasification of wastewater sludge

High temperature steam gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with steam gasification. The use of steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the syngas properties from sewage sludge are presented here at various steam to carbon ratios at a reactor temperature of 1173 K. Effect of steam to carbon ratio on syngas properties are evaluated with specific focus on the amounts of syngas yield, syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum steam to carbon ratio of 5.62 for the range of conditions examined here for syngas yield, hydrogen yield, energy yield and energy ratio of syngas to sewage sludge fuel. The results show that steam gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.     

300MW燃煤锅炉协同处置干化污泥的试验研究

研究了污泥干化设备的干化效率以及干化污泥掺烧后对300 MW燃煤锅炉的影响。通过对污泥干化设备的物料和能量平衡计算发现其干化效率达到了89.5%;通过污泥的不同掺烧比例试验,分析了掺烧干化污泥后对烟气和飞灰中二恶英和重金属含量、烟气中SO2等以及其他运行情况的影响,结论表明掺烧一定比例的污泥对锅炉的正常运行没有明显影响,而且添加适当比例的污泥可以优化锅炉的运行,对环境保护方面的贡献不言而喻。     

Characteristics of tar,NOx precursors and their absorption performance with different scrubbing solvents during the pyrolysis of sewage sludge

Recently thermal utilizations of sewage sludge, especially pyrolysis and gasification, are regarded as promising technologies due to efficient utilization of fuel gas. In this study, characteristics of tar and NOx precursors were investigated during the pyrolysis of sewage sludge. Moreover, absorption performance for tar and NOx precursors were also studied by using four kinds of scrubbing mediums: cooking oil, diesel oil, BDF and water. The results showed that nitrogenous light PAHs were the major components of nitrogenous tar produced from the pyrolysis of sewage sludge. As for gravimetric tar and major nitrogenous tar compounds removal, cooking oil was the most suitable absorbent. With respect to NOx precursors, it was concluded that HCN, sharing of about 39.5% of total nitrogen of the sewage sludge, was the main NOx precursor gas whereas NH₃ content could be neglected. Absorption capacity of hydrophobic scrubbing mediums against NOx precursor gases could be arranged as followed: diesel oil > cooking oil > BDF.     

Air gasification of dried sewage sludge in a two-stage gasifier. Part 2: Calcined dolomite as a bed material and effect of moisture content of dried sewage sludge for the hydrogen production and tar removal

In order to produce a clean producer gas, the air gasification of dried sewage sludge was conducted in a two-stage gasifier that consisted of a bubbling fluidized bed and a tar-cracking zone. The kind and amount of bed materials, the kind of additives in the upper-reactor, and the moisture content in the sewage sludge were selected as operating variables in order to investigate their effects on the development of the producer gas characteristics. In our experiments, the gasification of a dried sewage sludge sample containing 30 wt.% of moisture with a combination of calcined dolomite as the bed material and activated carbon in the tar-cracking zone removed the most tar and produced the highest hydrogen concentration. The total tar removal efficiency and the H₂ content in the producer gas from the sample noted above reached 88.4% and 32.1 vol.%, respectively. The LHVs of all the producer gases were high with values above 7 MJ Nm⁻³.     

Pyrolysis gasification of dried sewage sludge in a combined screw and rotary kiln gasifier

A pyrolysis gasifier, with carbonization and activation steps, was developed to convert dried sludge into activated char and gas fuel energy. To determine the optimal driving conditions, parametric investigations were conducted on the amount of steam input, pyrolysis gasifier temperature and moisture content in the dried sludge.     

污泥在桨叶式干燥机内干化特性研究

针对采用桨叶式干燥机对城市生活污水污泥进行干燥这一课题,研究了生活污泥在桨叶式干燥机内的干燥效果,分析了干燥机热轴转速和导热油温对污泥干燥过程的影响.     

城市污水污泥热解特性实验研究

为了获得南昌市青山湖污水处理厂污泥的热解特性,采用差热天平对污泥进行热重分析实验,获得了不同加热速率下污泥的TG-DTG曲线。根据实验结果对干燥污泥热解过程进行了分析,并对实验数据进行了处理。利用微分法确定了热解机理并求出反应动力学参数——频率因子A、活化能E。     

A review of methods for the thermal utilization of sewage sludge: The Polish perspective

On the basis of demographic projections, it is estimated that the quantity of sewage sludge which will be produced in Poland between 2010 and 2018 will increase from 612.8 thousand tons (dry basis, d.b.) to 706.6 thousand tons (d.b.). Currently, the predominant method for the disposal of this sludge is its storage and agricultural application. However, the legislation taking effect in the next few years will effectively block these avenues of sewage-sludge disposal. Therefore, effective methods of thermal sewage-sludge utilization must be developed. Here we review the state of knowledge and technology in thermal methods for the utilization of municipal sewage sludge to obtain useful forms of energy such as pyrolysis, gasification, combustion, and co-combustion.     

Evaluation of the influence of biomass co-combustion on boiler furnace slagging by means of fusibility correlations

In order to show the influence of co-firing biomass with bituminous coal on ash properties, calculations of fusibility correlations have been carried out. Two Upper Silesian coals (with lower—LS and higher—HS slagging inclination) were chosen for emphasizing the influence of basic fuel. Four kinds of biomass were considered: straw, wood, dried sewage sludge and bone meal. Chemical constitutions of the mineral matter as well as the results of calculations are presented in Tables 2–5. The general conclusion is that co-firing biomass increases the fireside slagging hazard. The most difficult additional fuels are sludge and bone meal.