生物質(zhì)發(fā)電中英文對(duì)照外文翻譯文獻(xiàn)

1、 中英文對(duì)照外文翻譯(文檔含英文原文和中文翻譯)原文：Biomass co-firing options on the emission reduction and electricitygeneration costs in coal-fired power plantsAbstractCo-firing offers a near-term solution for reducing CO2 emissions fromconventional fossil fuel power plants. Viable alternatives to long-term CO2 reductiont

2、echnologies such as CO2 sequestration, oxy-firing and carbon loop combustion arebeing discussed, but all of them remain in the early to mid stages of development.Co-firing, on the other hand, is a well-proven technology and is in regular use thoughdoes not eliminate CO2 emissions entirely. An increm

3、ental gain in CO2 reduction canbe achieved by immediate implementation of biomass co-firing in nearly all coal-firedpower plants with minimum modifications and moderate investment, making co-firinga near-term solution for the greenhouse gas emission problem. If a majority ofcoal-fired boilers operat

4、ing around the world adopt co-firing systems, the totalreduction in CO2 emissions would be substantial. It is the most efficient means ofpower generation from biomass, and it thus offers CO2 avoidance cost lower than thatfor CO2 sequestration from existing power plants. The present analysis examines

5、 several co-firing options including a novel option external (indirect) firing usingcombustion or gasification in an existing coal or oil fired plant. Capital and operatingcosts of such external units are calculated to determine the return on investment. Twoof these indirect co-firing options are an

6、alyzed along with the option of directco-firing of biomass in pulverizing mills to compare their operational merits and costadvantages with the gasification option.1. IntroductionThe evidence of the effects of anthropogenic emission on global climate isoverwhelming 1. The threat of increasing global

7、 temperatures has subjected the useof fossil fuels to increasing scrutiny in terms of greenhouse gas (GHG) and pollutantemissions. The issue of global warming needs to be addressed on an urgent basis toavoid catastrophic consequences for humanity as a whole.Socolow and Pacala 2 introduced the wedge

8、concept of reducing CO2emissions through several initiatives involving existing technologies, instead of asingle future technology or action that may take longer to develop and strongerwillpower to implement. A wedge represents a carbon-cutting strategy that has thepotential to grow from zero today

9、to avoiding 1 billion tons of carbon emissions peryear by 2055. It has been estimated 3 that at least 15 strategies are currentlyavailable that, with scaling up, could represent a wedge of emissions reduction.Although a number of emission reduction options are available to the industry,many of them

10、still face financial penalties for immediate implementation. Somemeasures are very site/location specific while others are still in an early stage ofdevelopment. Carbon dioxide sequestration or zero emission power plants representthe future of a CO2 emissions-free power sector, but they will take ye

11、ars to come tothe mainstream market. The cost of CO2 capture and sequestration is in the range of40e60 US$/ton of CO2, depending on the type of plant and where the CO2 is stored4,5. This is a significant economic burden on the industry, and could potentiallyescalate the cost of electricity produced

12、by as much as 60%.Canada has vast amounts of biomass in its millions of hectares of managedforests, most of which remain untapped for energy purposes. Currently, large quantities of the residues from the wood products industry are sent to landfill or areincinerated 6. In the agricultural sector, gra

13、in crops produce an estimated 32 milliontons of straw residue per year. Allowing for a straw residue of 85% remaining in thefields to maintain soil fertility, 5 million tons would still be available for energy use.Due to an increase in land productivity, significant areas of land in Canada, whichwer

14、e earlier farmed, are no longer farmed. These lands could be plantedwithfast-growing energy crops, like switch-grass offering potentially large quantitiesof biomass for energy production 6.Living biomass plants absorb CO2 from the atmosphere. So, itscombustion/gasification for energy production is c

15、onsidered carbon neutral. Thus if acertain amount of biomass is fired in an existing fossil (coal, coke or oil) fuel firedplant generating some energy, the plant could reduce firing the corresponding amountof fossil fuel in it. Thus, a power plant with integrated biomass co-firing has a lowernet CO2

16、 contribution over conventional coal-fired plants.Biomass co-firing is one technology that can be implemented immediately innearly all coal-fired power plants in a relatively short period of time and without theneed for huge investments. It has thus evolved to be a near-term alternative toreducing t

17、he environmental impact of electricity generation from coal. Biomassco-firing offers the least cost among the several technologies/ options available forgreenhouse gas reduction 7. Principally, co-firing operations are not implemented tosave energy but to reduce cost, and greenhouse gas emissions (i

18、n some cases).In atypical co-firing plant, the boiler energy usage will be the same as it is operated at thesame steam load conditions (for heating or power generation), with the same heatinput as that in the existing coal-fired plant. The primary savings from co-firing resultfrom reduced fuel costs

19、 when the cost of biomass fuel is lower than that of fossil fuel,and avoiding landfill tipping fees or other costs that would otherwise be required todispose of unwanted biomass. Biomass fuel at prices 20% or more below the coalprices would usually provide the cost savings needed 8.2. Co-firing opti

20、onsBiomass co-firing has been successfully demonstrated in over 150 installations worldwide for a combination of fuels and boiler types 9. The co-firing technologiesemployed in these units may be broadly classified under three types:i. Direct co-firing,ii. indirect co-firing, andiii. gasification co

21、-firing.In all three options, the use of biomass displaces an equivalent amount of coal(on an energy basis), and hence results in the direct reduction of CO2 and NOxemissions to the atmosphere. The selection of the appropriate co-firing option dependson a number of fuel and site specific factors. Th

22、e objective of this analysis is todetermine and compare the economics of the different co-firing options. Briefdescriptions of the three co-firing options are presented here.2.1. Direct co-firingDirect co-firing involves feeding biomass into coal going into the mills, thatpulverize the biomass along

23、 with coal in the same mill. Sometime separate mills maybe used or biomass is injected directly into the boiler furnace through the coal burners,or in a separate system. The level of integration into the existing plant dependsprincipally on the biomass fuel characteristics.Four different options are

24、 available to incorporate biomass cofiring in pulverizedcoal power plants 10. In the first option, the pre-processed biomass is mixed withcoal upstream of the existing coal feeders. The fuel mixture is fed into the existingcoal mills that pulverize coal and biomass together, and distribute it across

25、 theexisting coal burners, based on the required co-firing rate. This is the simplest option,involving the lowest least capital costs, but has a highest risk of interference with thecoalfiringcapability oftheboilerunit.Alkaliorotheragglomeration/corrosion-causing agents in the biomass can build-up o

26、n heatingsurfaces of the boiler reducing output and operational time 11. Furthermore,different combustion characteristics of coal and biomass may affect the stability andheat transfer characteristics of the flame 12. Thus, this direct co-firing option isapplicable to a limited range of biomass types

27、 and at very low biomass-to-coalco-firing ratios. The second option involves separate handling, metering, and pulverization ofthe biomass, but injection of the pulverized biomass into the existing pulverized fuelpipe-work upstream of the burners or at the burners. This option requires onlymodificati

28、ons external to the boiler. One disadvantage would be the requirement ofadditional equipment around the boiler, which may already be congested. It may alsobe difficult to control and to maintain the burner operating characteristics over thenormal boiler load curve.The third option involves the separ

29、ate handling and pulverizationof the biomass fuel with combustion through a number of burners located in the lowerfurnace, dedicated to the burning of the biomass alone. This demands a highest capitalcost, but involves the least risk to normal boiler operation as the burners arespecifically designed

30、 for biomass burning and would not interfere with the coalburners.The final option involves the use of biomass as a reburn fuel for NOx emissioncontrol. This option involves separate biomass handling and pulverization, withinstallation of separate biomass fired burners at the exit of the furnace. As

31、 with theprevious option, the capital cost is high, but risk to boiler operation is minimal.2.2. Indirect or external co-firingIndirect co-firing involves the installation of a completely separate biomassboiler to produce low-grade steam for utilization in the coal-fired power plant prior tobeing up

32、graded, resulting in higher conversion efficiencies. An example of this optionis the Avedore Unit 2 project in Copenhagen, Denmark. In Canada, GreenfieldResearch Inc. has developed a similar CFB boiler design that utilizes a number ofunits of the existing power plant systems like ID fan etc. to redu

33、ce the capital cost. Inthis system, a subcompact circulating fluidized bed boiler is designed specifically tohave a piggy-back ride on an existing power plant boiler. Since it is not a stand-aloneboiler it does not need many of the equipment or component of a separate boiler. Thisunit releases flue

34、gas at relatively high temperature and joins the existing flow streamof the parent coal-fired boiler after air heater. Thus, the flue gas from the co-firingunit does not come in contact with any heating elements of the existing boiler, thus avoiding the biomass related fouling or corrosion problem,

35、which is the largestconcern of biomass cofiring.This boiler is totally independent of the parent unit, and as such, any outage inthe co-firing unit does not affect the generation of the parent plant. Thus this indirectcombustion-based option offers high reliability. The piggy-back boiler produces lo

36、wpressure steam feeding into the process steam header of the power plant. Fig. 1 showsthe photograph of one such unit built by Greenfield Research Inc., for a 220MWePulverized coal-fired boiler in India. In this specific case, the piggy-back boiler firedwaste fuel from the parent boiler as that was

37、the need of the plant.2.3. Gasification co-firingCo-firing through gasification involves the gasification of solid biomass andcombustion of the product fuel gas in the furnace of the coal-fired boiler. Thisapproach offers a high degree of fuel flexibility. Since the gas can be injected directlyinto

38、the furnace for burning, the plant can avoid expensive flue gas cleaning as onewould need for syngas or fuel gas for diesel engines. As the enthalpy of the productgas is retained, this results in a very high energy conversion efficiency. If the biomasscontains highly corrosive elements like chlorine

39、, alkali etc., a certain amount of gascleaning may be needed prior to its combustion in the furnace.Another importantbenefit of injection of gas in the furnace is that it serves as a gas-over firing designedto minimize NOx.Although less popular, indirect or external and gasification cofiring options

40、 havecertain advantages, such as the possibility to use a wide range of fuels and easyremoval of ash. Despite the significantly higher capital investment requirement, theseadvantages make these two options more attractive to utility companies in some cases.3. Current status of biomass co-firingThere

41、 are a number of co-firing installations worldwide, with approximately ahundred in Europe, 40 in the US and the remainder in Australia and Asia (Fig. 2)9,13. Most of these installations employ direct co-firing, mainly because it is thesimplest and least cost option. Examples include the 635 MWe EPON

42、 Project ofGelderland Power Station in Holland which uses direct co-firing with waste wood and the 150 MWe Studstrup Power Plant, Unit 1, near Aarhus, Denmark co-firing straw.Gasification co-firing is also an attractive option. Three examples of the plantsoperating on this type of co-firing are: the

43、 137 MWe Zeltweg Power Plant in Styria inAustria, the AMERGAS biomass gasification project at the Amer Power Plant inGeertruidenberg, Holland, and the Kymiarvi power station at Lathi in Finland.The majority of biomass co-firing installations is operated at biomass: coalco-firing ratios of less than

44、10%, on a heat input basis. The successful operation ofthese plants shows that co-firing at low ratios does not pose any threat or majorproblems to the boiler operation.4.ConclusionCo-firing reduces the cost of CO2 reduction as its cost is potentially lower thanthat for CO2 sequestration in an exist

45、ing power plant. For example, the cost ofsequestration of 40e60$/ton of CO2 was much higher than the 33$/ton CO2 reductioncost through cofiring. The present analysis examines a special external co-firingoption in an existing plant with two other co-firing options: direct combustionco-firing, and gas

46、ification based indirect co-firing. An analysis carried out for a plantin the eastern Canada indicates that direct co-firing can offer an IRR of more thantwice that of indirect co-firing. Direct co-firing however suffers from a majoruncertainty about fouling and corrosion of its superheater tubes, a

47、nd breakdown of themills while handling biomass. This loss, conservatively estimated at 1%, could havesignificant impact on the viability of the co-firing option. The novel external co-firingoption, needs higher capital investment, but is entirely free from these uncertainties.For high alkali, high

48、chlorine biomass with high moisture content, the loss in capacityfactor could increase significantly. A sensitivity analysis of the effect of plantcapacity factor on the IRR indicates a strong dependency of IRR on the CapacityFactor (CF). IRR reduces at an increasing rate for a steady loss of CF. Ho

49、wever, theplant can operate viably even at a CF loss of 4%, offering an IRR of 22.2%. 譯文：生物質(zhì)混燃的燃煤電廠減排和發(fā)電成本的選擇混燒提供了減少傳統(tǒng)化石燃料電廠的二氧化碳排放量近期解決方案 。為減少二氧化碳排放量的長期技術(shù)，如二氧化碳封存，氧燃燒和碳循環(huán)燃燒可行的替代方案正在討論之中，但他們都留在早中期階段的發(fā)展。另一方面，是一種成熟的技術(shù)，是在經(jīng)常使用雖然不完全消除的二氧化碳排放量。在減少二氧化碳排放的增量增益可以通過立即執(zhí)行來實(shí)現(xiàn)生物質(zhì)混燃在幾乎所有的燃煤電廠最低限度的修改和溫和的投資，使得混燃的溫室氣

50、體排放問題的一個(gè)短期的解決方案如果大多數(shù)經(jīng)營世界各地的燃煤鍋爐采用聯(lián)合燃燒系統(tǒng)，CO2 排放總量減少將是巨大的。它是由生物質(zhì)發(fā)電的最有效的手段，因此它提供了避免 CO2 的成本低于從現(xiàn)有電廠二氧化碳封存。目前的分析考察幾個(gè)混燒選項(xiàng)，包括一個(gè)新的選項(xiàng)，使用外部燃燒或氣化在現(xiàn)有的煤或油（間接）射擊燃煤發(fā)電廠。這樣的外部單位的資本和運(yùn)營成本的計(jì)算，以確定投資回報(bào)率。這些間接共燃兩種選項(xiàng)是生物質(zhì)直接混燃在粉碎廠與氣化選項(xiàng)比較它們的優(yōu)劣運(yùn)營和成本優(yōu)勢的選項(xiàng)一起進(jìn)行分析。1.簡介對(duì)全球氣候人為排放的影響的證據(jù)是壓倒性的1。增加全球氣溫的威脅已經(jīng)承受的化石燃料的使用在溫室氣體（GHG）和污染物排放方面越來越

51、嚴(yán)格的審查。需要迫切的基礎(chǔ)上加以解決，以避免對(duì)全人類造成災(zāi)難性后果的全球變暖問題。索科洛和帕卡拉2提出通過包括現(xiàn)有的技術(shù)若干舉措減少二氧化碳排放量的楔形概念，而不是一個(gè)單一的未來技術(shù)或操作，可能需要更長的時(shí)間來開發(fā)和更強(qiáng)的意志力來實(shí)現(xiàn)。楔形表示通過 2055 具有從今天零增長到避免 1 十億噸年碳排放的潛在據(jù)估計(jì)一個(gè)碳 - 切割策略3，在至少 15 的策略是目前可用的，具有擴(kuò)大，可能代表減排的楔子。雖然一些減排方案是適用于本行業(yè)，其中許多人仍面臨立即實(shí)施經(jīng)濟(jì)處罰。 有些措施是非常的網(wǎng)站/具體位置而另一些仍處于發(fā)展的早期階段。二氧化碳封存或零排放發(fā)電廠代表二氧化碳零排放電力行業(yè)的未來，但他們將需

52、要數(shù)年時(shí)間來市場的主流。 CO2 捕獲和封存的成本在 40e60 US $ /噸 CO 2 的范圍內(nèi)，這取決于植物的類型和其中二氧化碳被存儲(chǔ)4,5。這是對(duì)行業(yè)一個(gè)顯著的經(jīng)濟(jì)負(fù)擔(dān)，并有可能升級(jí)多達(dá) 60的所產(chǎn)生的電力的成本。加拿大有大量在數(shù)以百萬計(jì)管理的森林，其中大部分尚未開發(fā)的能源用途公頃的生物量。目前，大批量從木制品行業(yè)的殘基被送到垃圾填埋場或焚化6。在農(nóng)業(yè)部門，糧食生產(chǎn)作物，估計(jì) 3200 萬噸，每年秸稈殘?jiān)Ｔ试S的 85的剩余的領(lǐng)域保持土壤肥力秸稈渣，500 萬噸仍然將可用于能源的使用。由于增加了土地產(chǎn)出率，在加拿大的土地，這是早期的養(yǎng)殖顯著的地區(qū)，不再養(yǎng)殖。這些土地可以種植 withf

53、ast 種植能源作物，如柳枝稷提供潛在的大量生物質(zhì)的能源生產(chǎn)6。活體生物量植物吸收大氣中的二氧化碳。因此，用于能源生產(chǎn)其燃燒/氣化被認(rèn)為是碳中性的。因此，如果生物質(zhì)的一定量的在現(xiàn)有的化石（煤，焦炭或石油）燃料燃燒植物燃煤發(fā)電機(jī)一些能量，所述植物可以減少燒制中它的化石燃料的相應(yīng)量。因此，集成了生物質(zhì)混燃電廠與常規(guī)燃煤發(fā)電廠降低二氧化碳凈貢獻(xiàn)。生物質(zhì)共燒是一種技術(shù)，能夠在一段相對(duì)較短的時(shí)間，并無需巨大的投資立即被實(shí)現(xiàn)在幾乎所有的燃煤電廠。因此它已演變成為一個(gè)短期替代減少發(fā)電的煤環(huán)境的影響。生物質(zhì)混燃提供了多種技術(shù)之間的最低成本/供溫室氣體減排方案原則上，共燒操作不執(zhí)行，以節(jié)省能源，但可以減少成本，

54、和溫室氣體排放（在某些情況下）。在一個(gè)典型的共燒植物，鍋爐能量使用將是因?yàn)樗窃谙嗤恼羝?fù)載條件（用于加熱或發(fā)電）操作的相同，具有相同的熱輸入作為在現(xiàn)有的燃煤電廠。主儲(chǔ)蓄從共燒燃料成本降低的結(jié)果，當(dāng)生物質(zhì)燃料的成本比化石燃料，以及避免垃圾傾倒費(fèi)或否則將需要處置不需要的生物質(zhì)的其它費(fèi)用。的價(jià)格低于煤的價(jià)格的 20或更多的生物量燃料通常會(huì)提供8所需要的成本節(jié)約。2.混燒的選擇生物質(zhì)共燒已成功地展示了在超過 150 安裝全球燃鍋爐類型的組合9。在這些單元中所采用的共燒技術(shù)可被大致分為以下三種類型：1.直接混燒 2.間接混燒3.氣化混燒在所有三個(gè)選項(xiàng)中，利用生物質(zhì)的取代煤的等效量（能量的基礎(chǔ)上），并

55、因此導(dǎo)致向大氣直接還原二氧化碳和 NOx 的排放。合適的共燒選項(xiàng)的選擇取決于若干燃料和位點(diǎn)特異性因子。此分析的目的是確定和比較的不同共燒選項(xiàng)的經(jīng)濟(jì)性。三個(gè)共燒選項(xiàng)的簡要描述這里介紹2.1.直接混燒直接混燒生物質(zhì)被送到軋機(jī)里去，在同一磨機(jī)粉碎生物質(zhì)與煤一起。有時(shí)也可以使用單獨(dú)的磨機(jī)或生物量是通過粉煤燃燒器直接注射到鍋爐爐或在一個(gè)單獨(dú)的系統(tǒng)中。集成水平到現(xiàn)有植物主要依賴于生物質(zhì)燃料的特性。四種不同的選項(xiàng)納入生物質(zhì)混燃煤粉發(fā)電廠10。在第一個(gè)選項(xiàng)，預(yù)加工的生物量是與現(xiàn)有的給煤機(jī)的煤的上游混合。燃料混合物被供給到該粉碎煤和生物質(zhì)一起，并在現(xiàn)有的粉煤燃燒器，分發(fā)現(xiàn)有磨煤機(jī)的基礎(chǔ)上，需要共燒率。這是最簡單的選擇，涉及到至少最低的資金成本，但與鍋爐機(jī)組的燃煤能力干擾的風(fēng)險(xiǎn)最高。在生物量的堿金屬或其它附聚/腐蝕引起試劑可堆積在鍋爐減少輸出和操作時(shí)間11的加熱表面。此外，煤和生物質(zhì)的不同的燃燒特性的可能影響火焰12的穩(wěn)定性和熱傳導(dǎo)特性。因此，這種直接共燒選項(xiàng)是適用于生物質(zhì)類型的有限范圍，并在非常低的生物質(zhì)煤混燒比率。第二個(gè)方案涉及及單獨(dú)的處理，計(jì)量，和生物質(zhì)的粉碎中，但已粉碎生物質(zhì)注入到燃燒器的現(xiàn)有粉碎燃料管工作的上游或在燃燒器。此選項(xiàng)需要僅修改外部