共查询到20条相似文献，搜索用时 46 毫秒
1.
Renewable chemical commodity feedstocks from integrated catalytic processing of pyrolysis oils 总被引：1，自引：0，他引：1
Fast pyrolysis of lignocellulosic biomass produces a renewable liquid fuel called pyrolysis oil that is the cheapest liquid fuel produced from biomass today. Here we show that pyrolysis oils can be converted into industrial commodity chemical feedstocks using an integrated catalytic approach that combines hydroprocessing with zeolite catalysis. The hydroprocessing increases the intrinsic hydrogen content of the pyrolysis oil, producing polyols and alcohols. The zeolite catalyst then converts these hydrogenated products into light olefins and aromatic hydrocarbons in a yield as much as three times higher than that produced with the pure pyrolysis oil. The yield of aromatic hydrocarbons and light olefins from the biomass conversion over zeolite is proportional to the intrinsic amount of hydrogen added to the biomass feedstock during hydroprocessing. The total product yield can be adjusted depending on market values of the chemical feedstocks and the relative prices of the hydrogen and biomass. 相似文献
2.
Renewable raw materials may be converted by biological means to feedstocks for the chemical industry. Glucose from cornstarch is the current choice as a substrate, although advances may enable the use of less expensive lignocellulosic materals. The production of oxychemicals and their derivatives from renewable resources could amount to about 100 billion pounds annually, or about half of the U.S. production of organic chemicals. Ethanol produced by fermentation is now cost-competitive with industral ethanol produced from fossil fuel. Biological routes to other oxychemicals exist and are expected to be important in the future. Several product recovery methods may be used, but new energy-conserving methods will be needed to make the engineering-biology combinations economical. 相似文献
3.
Goldstein IS 《Science (New York, N.Y.)》1975,189(4206):847-852
The conversion of wood into chemicals for the production of most of our synthetic plastics, fibers, and rubbers is technically feasible. With refinements in technology a large integrated plant utilizing all components of the wood for production of ethanol (to be further processed to ethylene and butadiene), phenols and furfural would be approaching economic feasibility as well at current petrochemical prices. If crude oil prices continue to climb at a faster rate than wood costs, the economic feasibility of chemicals for polymers from wood would become certain. Although technical feasibility has not been established, synthetic oils from liquefaction of wood might serve as feedstocks for cracking to chemicals in the same way that crude oil is presently used. The fulfillment of all our polymer needs from wood as a raw material should not place an impossible burden on our wood supply, but might actually improve the availability of wood for lumber, plywood and pulp by providing a use for less valuable wood which would allow reforestation and improved forest management. 相似文献
4.
Pruett RL 《Science (New York, N.Y.)》1981,211(4477):11-16
Rapid increases in the price of imported crude oil have accelerated a shift in the raw material base for chemical feedstocks from natural gas to crude oil to coal. Widespread use of ethylene as a feedstock has depended on the availability at attractive prices of natural gas and petroleum. As the resource base shifts from natural gas and petroleum to coal, ethylene is being replaced by synthesis gas (a mixture of hydrogen and carbon monoxide of varying composition), which can be manufactured directly from any of these carbonaceous sources. This trend is expected to accelerate in the 1980's. Organics likely to be produced from synthesis gas include ethanol, ethylene glycol, and vinyl acetate. 相似文献
5.
Torres Galvis HM Bitter JH Khare CB Ruitenbeek M Dugulan AI de Jong KP 《Science (New York, N.Y.)》2012,335(6070):835-838
Lower olefins are key building blocks for the manufacture of plastics, cosmetics, and drugs. Traditionally, olefins with two to four carbons are produced by steam cracking of crude oil-derived naphtha, but there is a pressing need for alternative feedstocks and processes in view of supply limitations and of environmental issues. Although the Fischer-Tropsch synthesis has long offered a means to convert coal, biomass, and natural gas into hydrocarbon derivatives through the intermediacy of synthesis gas (a mixture of molecular hydrogen and carbon monoxide), selectivity toward lower olefins tends to be low. We report on the conversion of synthesis gas to C(2) through C(4) olefins with selectivity up to 60 weight percent, using catalysts that constitute iron nanoparticles (promoted by sulfur plus sodium) homogeneously dispersed on weakly interactive α-alumina or carbon nanofiber supports. 相似文献
6.
Wishart RS 《Science (New York, N.Y.)》1978,199(4329):614-618
The future growth of the petrochemical industry depends in part on the industry's ability to improve efficiency in the use of oil and gas feedstocks and to develop promising alternatives. Technological innovation is proving to be the key to the long-term viability of the industry. The next 6 to 7 years will be characterized by the commercialization of new technologies designed to improve the efficiency of petroleum as a feedstock. Union Carbide's advanced cracking reactor, now nearing the demonstration stage, exemplifies this type of effort. The increasing price of oil and gas will make coal-based synthesis gas more attractive as a feedstock, particularly for oxygenated petrochemical products. A further development involves the conversion of biomass, through fermentation, to useful chemical products and the gasification of municipal wastes to raise steam for electricity generation and as a possible, supplemental feedstock. By the year 2000, it is predicted that feedstocks from all sources other than oil and gas may constitute 10 to 14 percent of the total new material requirement for the petrochemical industry. 相似文献
7.
中国禽蛋产业链短期市场价格传导机制 总被引：11，自引：1，他引：10
【目的】禽蛋产业链价格传导涉及生产、流通、消费各个环节,笔者以禽蛋的主要产品——鸡蛋为研究对象,从上、中、下游整个产业链角度动态分析禽蛋产业链短期市场价格间的传导机制,以便能够适时监测及预警禽蛋产品的短期价格波动,减少短期价格波动的频繁发生。【方法】首次应用月度数据对中国禽蛋产业链短期市场价格传导机制进行研究,运用协整检验、向量误差修正模型(VEC)分析鸡蛋产业链中的商品蛋用雏鸡价格(简称雏鸡价)、蛋用配合饲料价格(简称饲料价)、鸡蛋批发市场价格(简称批发价)和鸡蛋零售市场价格(简称零售价)的价格传导关系,并应用方差分解、脉冲响应函数和Granger因果关系检验确定价格间的传导路径及强度。【结果】鸡蛋产业链各环节短期市场价格间存在协整关系,雏鸡价、饲料价、批发价分别变动1%,将会引起零售价变动0.23%、-0.09%和1.04%;鸡蛋产业链价格系统的长期均衡关系制约着短期价格波动,误差修正项的系数为负,其修正强度达17.0%,符合反向修正机制;鸡蛋产业链短期市场价格间的传导并非通畅,在某些环节存在着阻滞现象。其中,下游零售价到上游饲料价、上游饲料价到中游批发价、上游雏鸡价到饲料价、下游零售价到上游雏鸡价、上游雏鸡价到中游批发价、下游零售价到中游批发价的价格传导均存在1个月时滞。【结论】中国鸡蛋产业链各短期市场价格之间存在着长期均衡关系,这种长期均衡关系制约着短期价格波动,以自动减弱价格之间的偏离,促使各种价格走向均衡。鸡蛋价格传导机制主要表现为成本推进型,即由上游产品价格变化引起中游和下游产品价格变化。鸡蛋产业链各价格传导并非通畅,在一些环节存在着阻滞现象,需要相关政府部门制订相应措施,保证价格传导的顺畅,提高价格传导的效率。 相似文献
8.
The basic concepts for thermochemical hydrogen generation processes have been summarized in this article. A useful set of criteria has been described for the screening and selection of potentially viable, multistep, closedcycle thermochemical processes for hydrogen generation. Three illustrative, new closed-cycle processes have been discussed, indicating potential, overall thermal efficiencies ranging from approximately 40 to 60 percent. Combined thermochemical-electrolytic schemes also warrant further consideration. Principal technical problems in the development of such thermochemical closed-cycle and mixed-cycle processes are expected to include primarily materials compatibility, reaction kinetics, separation techniques, and heat-exchanger systems. As natural gas supplies decline and prices rise, new open-cycle thermochemical processes based on water and other fossil fuel feedstocks will be the first important new technology in supplying the growing hydrogen needs of industry for at least the next two decades. Conventional electrolysis technology does not appear to be a competitor for large-scale supplies in this century unless very low off-peak electrical power rates become available, although electrolysis will be the best technique for some small-scale uses. Further analysis will be required to determine if closed-cycle thermochemical or mixed-cycle methods will displace electrolysis or other methods as the principal technology for the production of hydrogen on a large scale for the longer term. 相似文献
9.
化肥行业近几年很受委屈,"农民种粮的收入增幅被化肥涨价吃掉了"这一说法似乎成为爱农护农的标签,也成了媒体报道涉及肥价的既定套路。化肥价格增长就永远被农民所抱怨,好像成了农民增收的拦路虎。对此,我们不否认化肥价格在最近几年整体出现了上涨,但是要看到化肥生产的各类成本都在大幅度地增长,化肥企业并没有因此而大幅抬价,反倒是一直考虑农民的承受能力,保证这一刚性需求的生产资料价格相当平稳。为此,本刊通过对近几年的统计数据进行系统分析,发现化肥价格的增长幅度与我们印象中的结论相差甚远。 相似文献
10.
Primary alcohols from terminal olefins: formal anti-Markovnikov hydration via triple relay catalysis
Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive; an indirect hydroboration/oxidation sequence requiring stoichiometric borane and oxidant is currently the most practical methodology. Here, we report a more direct approach with the use of a triple relay catalysis system that couples palladium-catalyzed oxidation, acid-catalyzed hydrolysis, and ruthenium-catalyzed reduction cycles. Aryl-substituted terminal olefins are converted to primary alcohols by net reaction with water in good yield and excellent regioselectivity. 相似文献
11.
Lipinsky ES 《Science (New York, N.Y.)》1981,212(4502):1465-1471
As a source of chemicals, biomass has several intrnsic advantages over fossil mass: it is renewable, flexible through crop switching, and adaptable through genetic manipulation. Inflexibility of the fossil mass resource is compensated for by highly effective technology for production of olefins and aromatics, economies of scale, and a highly developed system of conversion products with large markets. Direct and indirect strategies to substitute for petrochemicals are based on ecological succession concepts. A proliferation of lignocellulosic fractionation processes is arising from the need for inexpensive, homogeneous, chemically useful biomass feedstocks. 相似文献
12.
为了解猪肉产业链各环节价格的传导机制,考察各价格传导方向及传导路径是否畅通,采用中国牧业信息网及商务部2004年1月—2014年3月的月度数据,运用协整检验和向量误差修正模型对猪肉产业链各环节的价格传导机制进行实证分析。中国猪肉产业链各环节市场价格存在长期的均衡关系;误差修正模型中的误差修正的强度为2.3%,对促使市场价格系统均衡影响较小,因此不能完全依靠市场供求系统的自发力量调节猪肉产业链中各种价格的系统均衡;猪肉产业链各环节间价格传导不是完全通畅,有些环节存在1期或2期的传导时滞;猪肉产业链的价格传导表现为下游向上游传导、下游向中游传导以及中游向上游传导,是需求拉动型。应密切关注猪肉市场零售价格,以零售价格为信号,预测产业链各环节价格的近期走势,以利于养殖户和批发商准确把握市场信息,避免价格波动带来的收入损失。 相似文献
13.
2008年下半年的金融危机导致饲料原料价格全面下滑,伴随大的经济走势来看,2009年原料价格波动将缓解,大起大落的复杂局面难免再发生,这增加了饲料企业经营的负担。饲料价格的相对稳定为蛋鸡养殖的可预见性创造了条件,研究证明,规模出效益,本文拟积极引导蛋鸡养殖业,推动产业升级,使蛋鸡养殖向规模化、标准化方向发展。 相似文献
14.
Bell S Wüstenberg B Kaiser S Menges F Netscher T Pfaltz A 《Science (New York, N.Y.)》2006,311(5761):642-644
Asymmetric hydrogenation of olefins is one of the most useful reactions for the synthesis of optically active compounds, especially in industry. However, the application range of the catalysts developed so far is limited to alkenes with a coordinating functional group or an aryl substituent next to the double bond. We have found a class of chiral iridium catalysts that give high enantioselectivity in the hydrogenation of unfunctionalized, trialkyl-substituted olefins. Because these catalysts do not require the presence of any particular functional group or aryl substituent in the substrate, they considerably broaden the scope of asymmetric hydrogenation. 相似文献
15.
三种不同生物质炭对2,4-二氯苯氧乙酸吸附特性的研究 总被引：1，自引：0，他引：1
以植物类生物质原料(玉米秸秆和毛杨树叶)、城市污泥两类原材料在400℃条件下制备生物质炭(秸秆、毛杨树叶以及城市污泥三种生物质炭分别表示为J400、Y400和W400),使用酸洗法去除生物质炭表面灰分优化生物质炭,采用批量吸附实验的方法分析三种生物质炭对2,4-二氯苯氧乙酸(简称2,4-D)的吸附特性,并结合元素分析及显微红外等分析方法,探讨生物质原料对生物质炭吸附2,4-D吸附特性的影响。结果表明:三种生物质炭的元素含量、O/C、H/C和(H+O)/C存在差异,大小顺序均为W400Y400J400,表明秸秆生物质炭具有更强的疏水性和更低的极性,有利于提高生物质炭对有机物的吸附能力。吸附试验显示秸秆生物质炭、杨树生物质炭、污泥生物质炭对2,4-D的吸附特性及吸附能力不同,吸附量大小依次为2.732、2.650、2.633 mg·g(-2)。三种生物质炭的红外光谱结果相似,但在O-H、饱和C-H和不饱和C-H面外振动等处存在差异;污泥生物质炭在吸附2,4-D后多处位点的吸收峰发生变化,而杨树和秸秆生物质炭发生变化的位点较少;污泥生物质炭与其他两种生物质炭对2,4-D的吸附机制差异较大。 相似文献
16.
About 25% of the world's fisheries are depleted such that their current biomass is lower than the level that would maximize the sustained yield (MSY). By using methods not previously applied in the fisheries conservation context, we show in four disparate fisheries (including the long-lived and slow-growing orange roughy) that the dynamic maximum economic yield (MEY), the biomass that produces the largest discounted economic profits from fishing, exceeds MSY. Thus, although it is theoretically possible that maximizing discounted economic profits may cause stock depletions, our results show there is a win-win: In many fisheries at reasonable discount rates and at current prices and costs, larger fish stocks increase economic profits. An MEY target that exceeds MSY and transfers from higher, future profits to compensate fishers for the transition costs of stock rebuilding would help overcome a key cause of fisheries overexploitation, industry opposition to lower harvests. 相似文献
17.
The potential for energy conservation through increased use of steel scrap by the U.S. steel industry is examined. It is concluded that increased use of scrap would reduce energy use, but it is not economical, due mainly to volatile scrap prices. Other energy-saving technologies exist, but it is likely that energy will be conserved through reduced use of steel as rising energy costs are passed through to consumers. 相似文献
18.
为探讨我国肉牛产业链主要环节价格非线性波动及其传递特征,基于2012年1月—2015年10月我国肉牛产业链主要环节价格数据,采用马尔可夫转换向量自回归(MS-VAR)模型进行实证分析。结果表明:肉牛产业链主要环节价格存在2种不同的运行状态,且呈现出明显的阶段性;第1个阶段为2012年初—2013年上半年,第2个阶段为2013年下半年—2015年;肉牛产业链在常规状态运行概率更高,持续时间更长,但两状态相互转换概率均较低,说明价格波动存在平滑性。肉牛产业链价格传递作用明显,架子牛价格在产业链价格传递过程中起主导作用;产业链价格传递在不同状态下作用存在差异,非常规状态下传递作用更为明显;价格传递作用持续时间一般在半年以上。 相似文献
19.
双重约束下原料奶价格波动的影响因素及其测度 总被引：1，自引：0，他引：1
针对中国奶业发展面临的双重约束,在分析原料奶价格波动的影响因素的基础上,构建VAR模型对影响中国原料奶价格波动的因素进行研究。从对原料奶价格波动的影响看,历史价格、进口替代、货币供应、生产成本和国际价格都对原料奶价格形成具有正向且长期的作用,而国内供给对原料奶价格形成存在负向的作用并逐期减弱变为正向;从对原料奶价格波动的贡献度看,价格形成的主要动力来源是历史价格、进口替代、成本因素和国际价格。因此,加强对奶业发展需求与供给趋势研判、发展适度规模经营、提高奶业生产的组织化程度、提高原料奶质量,有助于稳定原料奶价格波动,改善产业链利益分配机制。 相似文献