城市生活垃圾能源化技术的发展动态

简述了城市生活垃圾能源化的可行性,介绍了焚烧、垃圾衍生燃料、熔融、气化、液化等主要技术。     

城市垃圾焚烧与热能利用

结合城市垃圾特点，应用成熟可靠的垃圾焚烧技术，实现了能源有效回收与利用，达到了资源化的目的。     

垃圾焚烧的二次污染物排放处理

随着垃圾焚烧技术的不断发展,由此产生的二次污染问题也日益显现出来,主要包括垃圾焚烧所产生的飞灰污染、烟气中二恶英以及重金属的污染,特别是二恶英污染已引起全世界的关注,这对垃圾焚烧工艺的进一步发展提出了新的挑战。污染给人类的生存环境造成了很大的破坏,严重威胁着人类的安全。因而,二次污染物的排放控制问题成为亟待解决的问题。本文就垃圾焚烧所产生的二次污染物的排放处理进行讨论。     

城市生活垃圾燃烧特性的实验研究

分析研究生活垃圾的燃烧特性,通过实验分析垃圾的燃烧热值、着火温度、燃尽温度、失重速率等燃烧特性参数,并计算各种生活垃圾活化能。     

Biogas Production from the Organic Fraction of Municipal Solid Waste

This article discusses the potential use of biogas from municipal landfills to fuel urban heat space in Turkey. Biogas can be obtained from digesting the organic material of municipal solid wastes (MSW). The composition of MSW varies by the source of waste; however, in all cases the major constituents of MSW are organic in nature and the organics account for more than 50% of MSW. The main constituents of landfill gas are methane and carbon dioxide, both of which are major contributors to global warming. The generation of methane is worthwhile after one year from the start of the landfill operation. The compositional characteristics of MSW vary considerably from the large cities to the small towns and regions in Turkey. The social and demographic factors for each region are very different.     

A cold model analysis of solid waste incineration

A cold physical model to a scale of 1:33 of a solid waste incinerator was designed and constructed of transparent material. Experimentation aimed at optimizing gas flow patterns in the furnace for low-pollutant combustion. Flames were simulated by acid-base neutralization. Secondary air flow distribution and direction were identified as the controlling parameters of the flow pattern. The best possible air distribution for a desired flame shape and gas mixing was determined. Streamline plots for verification of the mathematical models were obtained.     

Employment of Anaerobic Digestion Process of Municipal Solid Waste for Energy

Abstract

Jordan is a country with a population of about five million people. It is considered a developing country that is deficient in generating its own energy source, and it relies significantly on imports of fuels from other countries, which plays an important role in various environmental related problems and issues. Jordan is distinguished among the developing countries by its reasonable industrialization and significant agricultural activities. The amount of waste generated is on the increase due to a continuing significant increase in population and it currently faces pollution of its limited fresh water sources. To mitigate the current and future environmental problems facing Jordan due to fossil fuel use and associated environment problems, Jordan is taking into consideration steps including the utilization of the biogas technology to replace fossil fuel, since Jordan is a nation striving to meet the expected energy demand that grows annually by 6%. Studies of quantity per capita estimates Jordan's generated daily waste as 8,000 tons, which is comparable to that of most semi-industrialized nations. Of that, 3,200 tons is household waste and the rest of it is waste related to industry or agricultural. Much of the total waste is organic, which could be utilized through a process of anaerobic digestion and already has been in use for decades in industrialized nations to produce clean burning methane gas, electricity, fuel, and fertilizers. Anaerobic digestion process releases no greenhouse gases to the atmosphere. Jordan's generated daily waste is estimated around the same as that of most moderately developing nations. Most of the total waste is organic, which could be utilized through a process of anaerobic digestion that does not release greenhouse gases to the atmosphere. Renewable energy and energy conservation, if efficiently utilized, might help to meet the expected increase demand on energy that is growing rapidly. A combined facility (landfill operation and biogas plant) that is established in the capital of Jordan could help reduce the disposal and accumulation of biodegradable solid waste significantly; by 90%. This will help reduce emissions of green house gases (CO₂), reduce the dependency of foreign fossil fuel and would improve issues related to the general environment. This project would be self-supported. This project, if proved to be successful, would be an example that others will follow throughout.     

城市生活垃圾气化熔融焚烧技术

近年来，为防止全球气候变暖，社会上对环境保护的要求日益严格。尤其是要求城市生活垃圾处理最大限度地采用无害化技术，抑制二恶英的排放。能够遏制二恶英产生和排放的无害化城市生活垃圾气化熔融焚烧技术被提出。本技术一般分两类，一类为垃圾气化 灰渣熔融焚烧技术，该技术的工艺流程为：先将城市生活垃圾在500-600℃温度下的热解气化制得可燃气体，制得的气体再根据用途进一步精制，垃圾中95%以上的含氯物质经济去所后所剩下的含碳灰渣在温度为1300℃以上的熔融燃烧设备中进行熔融处理，原垃圾中99.8%以上二恶英可被分解掉，无害化熔融渣可以多种用途；另一类为垃圾直接气化熔融焚烧技术，该技术的工艺流程为：交垃圾在温度1350-1500℃的熔融燃烧设备中进行熔融处理，原垃圾中的99.8%以上的二恶英可被分解掉。文章介绍新型城市生活垃圾气化熔融焚烧技术。     

Steam catalytic gasification of municipal solid waste for producing tar-free fuel gas

In the paper, a two-region municipal solid waste (MSW) steam catalytic gasification process was proposed. The gasifier was composed of two individual reactors: one is the gasification reactors and the other is the catalytic reactor. The MSW was initially gasified and the produced tar was gasified in the gasification reactor, and further, the tar not gasified entered the catalytic reactor together with the fuel gas and was catalytically decomposed to fuel gas. The influences of the catalysts, steam and temperature on the content of tar, dry gas yield and composition, and carbon conversion efficiency were studied. The results indicated that under the optimum operating conditions, the dry gas yield can be up to 1.97 Nm³/kg MSW and the tar in the product can be completely eliminated. The concentration of hydrogen, carbon monoxide and methane in the fuel gas produced was 50.8%, 9.32% and 13.3%, respectively.     

垃圾焚烧烟气余热利用的探讨

从利用烟气干燥物料的角度对干燥过程的认识、焚烧烟气的组成、烟气流动动力、烟气干燥模型、新型焚烧炉的特点、烟气温度的衡算等方面作了些分析与探讨。这对中小型焚烧炉烟气余热回收利用及其它工业炉降耗增效都具有一定的意义。     

Thermophilic composting of municipal solid waste

Process of composting has been developed for recycling of organic fraction of municipal solid waste (MSW). The bioreactor design was modified to reduce the composting process time. The main goal of this investigation was to find the optimal value of time period for composting of MSW in thermophilic bioreactor under aerobic condition. The temperature profiles correlated well with experimental data obtained during the maturation process. During this period biological degraders are introduced in to the reactor to accelerate the composting process. The compost materials were analyzed at various stages and the environmental parameters were considered. The final composting materials contained large organic content with in a short duration of 40 days. The quantity of volume reduction of raw MSW was 78%. The test result shows that the final compost material from the thermophilic reactor provides good humus to build up soil characteristics and some basic plant nutrients.     

城市固体废物焚烧过程中二恶英的生成和控制

文中综述了城市固体废物焚烧过程中二恶英的产生机理和影响因素，在此基础上介绍了垃圾焚烧过程中二恶英的各种控制技术和方法。     

生活垃圾燃烧特性实验研究

选取了城市生活垃圾中的厨余、纸张、织物、含氯塑料和不含氯塑料,进行元素分析、工业分析和热重分析,并在此基础上进行了几种垃圾混合物的燃尽实验。实验结果表明：生活垃圾的着火温度、活化能明显低于混合烟煤。而且塑料的燃烧规律与其它垃圾样品有显著区别。实验发现,随条件的不同,垃圾燃烧过程中会不同程度地产生CO、SO2和NOx,因此需要合理的燃烧组织,以降低污染的排放。     

An analysis of power generation from municipal solid waste (MSW) incineration plants in Taiwan

Heavily (about 99%) depending on imported energy, Taiwan, a country in the subtropics, has limited natural resources. In this regard, biomass energy from (MSW) municipal solid waste incineration plants thus became attractive during the 1990s. The objective of this paper is to present a comprehensive analysis of MSW-to-energy in Taiwan. This paper gave a concise summary of current status of domestic energy consumption &; power generation, MSW generation &; MSW incineration treatment, and electricity generation from MSW incineration plants since 2000. Based on the electricity generation in 2008 (i.e., 2967 GWh), the environmental benefit of mitigating CO₂ emissions and the economic benefit of selling electricity were preliminarily calculated to be around 1.9 × 10⁶ tons and US$ 1.5 × 10⁸, respectively. However, since the heat content of incinerated MSW and the methodologies were used on the recommendation of the (IPCC) Intergovernmental Panel on Climate Change, the net emissions of CO₂ equivalent from methane (CH₄) &; nitrous oxide (N₂O) have been estimated to be at around 76,000 and 88,000 tons/year compared to coal and oil, respectively.     

Supplying hydrogen vehicles and ferries in Western Norway with locally produced hydrogen from municipal solid waste

Gibbs free energy minimization has been used to estimate the hydrogen production potential of air gasification of the wet organic fractions of municipal solid waste available in the Bergen region in Western Norway. The aim of this work was to obtain an upper limit of the amount of hydrogen that could be produced and to estimate of the number of vehicles: passenger ferries and cars that could be supplied with an alternative fuel. The hydrogen production potential was investigated as function of waste composition, moisture content, heat loss, and carbon conversion factor. The amount of hydrogen annually available for both gasification and gasification combined with water-gas-shift-reaction was calculated for different scenarios. Up to 2700 tonne H₂ per year could be produced in the best case scenario; which would, if only utilised for maritime operations, be enough to supply nine ferries and ten fast passenger boat connections in the Hordaland region in Western Norway with hydrogen.     

Effect of particle size on pyrolysis of single-component municipal solid waste in fixed bed reactor

According to the differences in components, three representative components (plastic, kitchen garbage and wood) in municipal solid waste (MSW) were pyrolyzed in a fixed bed reactor to evaluate the influence of particle size on pyrolysis performance of single-component municipal solid waste (MSW). The bed temperature was set at 800°C and each sample was separated into three different size fractions (0–5 mm, 5–10 mm and 10–20 mm). The results show for all the samples particle size has an effect on pyrolysis product yields and composition: smaller particle size results in higher gas yield with less tar and char; the decrease of particle size can increase H₂ and CO contents of gas, as well as the ash and carbon element contents in the char. And the influence is the much more significant for sample with higher fixed carbon and ash contents, such as kitchen garbage, and less for sample with higher volatile content, plastic in the test.     

An experimental study on a novel shredder for municipal solid waste (MSW)

Based on composition and volume-mass properties of MSW (i.e., unit weight, void ratio, and water content), a new way for the breakage of the organic MSW is presented to effectively convert MSW to heat and fuel gas. A lab-scale shredder consisting of compaction and shredding chambers is designed and the breakage process of MSW in the shredder can be divided into three successive phases: deformation, further deformation, compressive shearing. The performances of the shredder, such as the effect of the rotor velocity and hydraulic pressure on product size distribution and specific energy are investigated. The results show that with hydraulic pressure the specific energy is reduced, and size distribution of product is finer. When hydraulic pressure is constant, the specific energy decreases with increasing rotor velocity, while the products size distribution is coarser.     

Energy potential from municipal solid waste in Malaysia

The average amount of municipal solid waste (MSW) generated in Malaysia is 0.5–0.8 kg/person/day and has increased to 1.7 kg/person/day in major cities. This paper highlights the MSW characteristics for the city of Kuala Lumpur. Currently, the waste management approach being employed is landfill, but due to rapid development and lack of space for new landfills, big cities in Malaysia are switching to incineration. A simple evaluation was conducted to establish the amount of energy that would be recovered based on the characteristics of the MSW if it were to be incinerated. From the characterization exercise, the main components of the Malaysian MSW were found to be food, paper and plastic, which made up almost 80% of the waste by weight. The average moisture content of the MSW was about 55%, making incineration a challenging task. The calorific value of the Malaysian MSW ranged between 1500 and 2600 kcal/kg. However, the energy potential from an incineration plant operating based on 1500 ton of MSW/day with an average calorific value of 2200 kcal/kg is assessed to be at 640 kW/day.     

Partitioning of heavy metals during municipal solid waste incineration on a laboratory fluid bed furnace

The content of heavy metals in the main physical compositions of municipal solid waste (MSW) is analyzed. The effects of temperature, chlorine and water on the partitioning of heavy metals are studied using a laboratory fluidized-bed (FB) furnace with simulated MSW composition. The experimental results show that temperature and chloride content in the feed have significant influence on the volatility of heavy metals, especially those of lower boiling point such as Hg, Cd and Zn. The influence of water is slight. Translated from Proceeding of the CSEE, 2005, 25(17): 100–104 [译自: 中国电机工程学报]     

A linear programming approach for the optimal planning of a future energy system. Potential contribution of energy recovery from municipal solid wastes

In the present paper the mismatch between the energy supply levels and the end use, in a broader sense, was studied for the Hellenic energy system. The ultimate objective was to optimize the way to meet the country's energy needs in every different administrative and geographical region using renewable energy sources (RES) and at the same time to define the remaining available space for energy recovery units from municipal solid waste (MSW) in each region to participate in the energy system. Based on the results of the different scenarios examined for meeting the electricity needs using linear programming and by using the exergoeconomic analysis the penetration grade was found for the proposed energy recovery units from MSWs in each region.