编制渤化小区工程概算的体会

作者根据自身体会，全面、系统地总结了编制一份高质量的概算文件必须注意的问题．     

Extraction and recovery of pectic fragments from citrus processing waste for co–production with ethanol

BACKGROUND: Approximately 0.7 ? 1 × 10⁶ dry tons of citrus processing waste (CPW) are produced annually in the United States. CPW is sold as animal feed but often the financial return does not exceed the production cost. Polysaccharides comprise 40% of the total dry matter of which pectin is the major component. CPW was steam treated to extract pectin fragments (PFs) as a value added co–product prior to fermentation of other sugars for biofuels production. RESULTS: PFs were extracted in high yields, along with polymeric arabinans, galactans and arabinogalactans. The extracted polysaccharides ranged in size from small oligomers to polymers of ～700 000 g mol^?1. Acidified treatments led to greater fragmentation of water soluble polysaccharides, but did not enhance fragmentation of pectins to small oligomers (> 30 mer). Methylesterified PFs, arabinans and galactans were recovered by ethanol precipitation while demethylesterified PFs were recovered and purified by precipitation with dilute HCl. CONCLUSION: Steam treatment of CPW provides for rapid, efficient fragmentation of protopectin into highly methylesterified PFs that could be recovered by precipitation. The steaming process for preparation of PFs is environmentally friendly. No toxic chemicals are introduced and the remaining CPW can be used in fermentations to produce ethanol and other compounds. © 2012 Society of Chemical Industry     

Lead recovery from aqueous environment by using porous carbon of citrus fruits waste: equilibrium,kinetics and thermodynamic studies

ABSTRACT

The mixture of citrus fruits (orange, grapefruit, mandarin, and lemon) wastes was utilized to obtain high surface area activated carbon (AC) by H₃PO₄ activation. The production conditions were optimized and the optimum conditions were determined. The optimal-activated carbon (CFWAC) was characterized by various physicochemical techniques. CFWAC was also used as a sorbent for Pb (II) ions from water. Batch experiments were performed to explore the adsorption capacity and mechanism. The Langmuir isotherm and pseudo-second-order kinetic model showed good fitness to the experimental data. The maximum Pb (II) adsorption capacity of CFWAC was found to be 163.93 mg/g.     

Short‐time estimation of biogas and methane potentials from municipal solid wastes

Biogas (GB) and methane (BMP) potentials are important parameters for the energy potential of the anaerobic digestion of municipal solid wastes (MSW) and to design full‐scale facilities. However, no standard protocol has been defined for this measure. Several samples of mixed MSW and the source‐selected organic fraction of municipal solid waste (OFMSW) obtained at different stages of their mechanical‐biological treatment were analyzed. GB and BMP values obtained at different times were correlated. Biogas potentials calculated at 3, 4, 5, 6, 7, 14, 21, 50 and 100 days correlated well for the OFMSW samples. In the case of the MSW samples, only GB values obtained at times of 14 or more days correlated well with the ultimate biogas production (considered at 100 days). The biogas potential analyzed at 21 days (as proposed in some standard methods) accounted for 77% of the total biogas potential in OFMSW samples and for 71% in the MSW samples. These results are useful for the correct design and operation of anaerobic digestion plants in terms of retention time estimation and expected biogas and methane production. Copyright © 2011 Society of Chemical Industry     

Evaluation of a simple batch distillation process for treating wastes from metalworking industries

A simple batch distillation process for the treatment of two types of industrial waste generated in a metalworking factory has been evaluated. Both types of waste are oil‐in‐water emulsions composed of numerous compounds and each type has a high content of water‐soluble species. The water‐soluble nature of the wastes precludes the use of conventional treatment technologies, such as ultrafiltration or chemical emulsion breaking, since they need to be complemented with additional treatment processes that would probably increase the cost considerably. A simple characterization of the liquid–vapour equilibrium and a scale‐up study has demonstrated the applicability of this technology. The process allows 90% of the waste to be recovered as water, thus achieving the required quality limits for discharge into a municipal wastewater treatment plant. An approximate estimation of capital investment and operating costs for an existing case has shown the economic viability of this process. Copyright © 2004 Society of Chemical Industry     

Methane emissions from rice paddies: a process study summary

Irrigated rice cultivation is one of the largest sources (approximately 15–20% of the annual total) of atmospheric methane, a potent greenhouse gas. This review examines the results of work performed over the past six years in which we have investigated the processes leading to the emission of methane from irrigated rice cultivation. These studies describe the daily and seasonal effects on methane production and emission of different planting dates, water management, organic amendments, soil texture, and cultivar choice. Because rice agriculture is one of the few sources of methane where emission reduction through management is considered possible, it promises to be a critical focus of mitigation efforts. We have identified several potential management practices for rice cultivation that may stabilize or reduce the emission of methane even in the face of future increased grain production necessary to meet the demands of an expanding world population. This revised version was published online in August 2006 with corrections to the Cover Date.     

空气吹除和真空脱氯的成本比较

介绍了空气吹除加化学法除氯和真空脱氯加化学法除氯的工艺流程，比较了空气吹除和真空脱氯的物料消耗、成本计算、工艺特点和经济社会效益。     

利用Excel表格计算复混肥料和掺混肥料的配方及成本

介绍利用Excel表格计算复混肥料和掺混肥料配方及成本的方法。该方法快速,有利于进行复混肥配方设计及成本测算,并可避免手工计算的诸多弊端。     

废物资源化制备生物质炭及其应用的研究进展

生物质炭作为一种多功能性材料正逐步受到人们的广泛关注。本文综述了以废弃物为原料制备生物质炭,给出了制备生物质炭的主要工艺,并对生物质炭的主要物理化学性质如元素组成、碱度、表面特性和孔隙结构进行了介绍。然后对生物质炭在农业和环境领域中的应用做了相应介绍,例如用作土壤改良剂提高土壤肥力、增加碳固定、减少温室气体排放,作为一种高效吸附剂同时去处污水中重金属及有机污染物等。最后,对今后生物质炭的研究方向作出了展望,指出应继续研究尽快实现生物质炭的大量、高效、廉价生产,从原料和工艺方面着手进一步提高生物质炭的比表面积,使其成为活性炭的替代品,同时进一步研究对土壤的改良和修复、对农作物生长和产量的促进以及对温室气体的减排作用的机理,并提供大面积的长期的实验数据支持。     

Excel表格在复混肥料配方与成本测算方面的应用

介绍Excel表格在复混肥料配方与成本测算方面应用的一些知识。该表格可操作性强,适合中小复混肥企业使用。     

有机固体废弃物热化学制氢研究进展

氢气是理想的清洁能源,也是重要的化工原料。但是,目前的制氢技术多以化石燃料为原料,制氢过程具有高能耗和高污染的弊端,这使氢能的清洁属性大打折扣。随着社会经济的发展和城市化进程的加快,城市固体废弃物的产量逐年递增,这其中的大部分有机物都有成为制氢原料的潜力。以有机固体废弃物（简称“有机固废”）为原料的制氢工艺对于氢能的清洁化发展和固废的资源化利用具有双重意义。本文以有机固废热化学转化制氢过程为对象,对该过程的原料预处理、技术路线、催化剂和吸附剂、技术经济分析、生命周期评价和生态风险评估等方面的研究进展进行综述,重点聚焦大型中试装置和工业化示范项目。通过分析各类技术路线的优劣性,总结得出新型热化学转化制氢技术受成本和装备的限制,大规模利用进展缓慢。在传统热化学转化制氢领域中,有机固废气化制氢最具大规模应用潜力。根据有机固废制氢的发展现状,还对该领域催化剂和吸附剂未来的研究方向以及技术经济分析和生命周期评价的热点问题进行讨论。最后对有机固废制氢的前景作出展望。     

煤制天然气废水处理技术研究现状及展望

为实现煤制天然气项目的"废水零排放",论述了煤制天然气"废水零排放"主要工艺,如酚氨回收、有机废水处理、含盐废水处理、浓盐水处理、高浓盐水处理、结晶盐处理等,并分析了各工序处理技术的特点及存在问题,并对煤制天然气及煤化工废水零排放处理发展趋势进行展望。未来应通过生产系统与水系统的优化,研究废水处理与利用的新途径,实现废水减量化;提高酚氨回收过程的回收效率及装置稳定性,降低运行成本;开发抗毒生化技术;研发高性能、抗污染膜材料,形成新工艺;开发经济、可靠的浓盐水脱除COD技术;开发高回收率、高纯度的分盐结晶工艺;形成煤化工废水结晶盐产品标准,促进废水结晶盐资源化利用。     

Anaerobic co‐digestion of food waste leachate and piggery wastewater for methane production: statistical optimization of key process parameters

BACKGROUND: Anaerobic co‐digestion of refractory liquid organic wastes is an alternative environmental management strategy with economic benefits arising out of biogas production. Laboratory‐scale experimental investigations were carried out on the anaerobic co‐digestion of two liquid organic wastes, food waste leachate (FWL) and piggery wastewater (PWW). Three important parameters affecting methane yield were chosen for this study, namely, mixing ratio, alkalinity and salinity, which were optimized using response surface methodology. RESULTS: The results were analyzed statistically and the optimum conditions identified as: mixing ratio (FWL: PWW) 33 (in terms of volatile solid, w/w) (2 on v/v), alkalinity 2850 mg CaCO₃ L^?1, and salinity 3.4 g NaCl L^?1. Under the optimum conditions, a cumulative methane yield (CMY) of 310 mL CH₄ g^?1 VS_added and VS reduction (VSR) of 54% were predicted. Mixing ratio and alkalinity showed the greatest individual and interactive effects on CMY and VSR (P < 0.05). A confirmation experiment under optimum conditions showed a CMY and VSR of 323 mL CH₄ g^?1 VS_added and 50%, respectively. This was only 1.04% and 1.1%, respectively, different from the predicted values. CONCLUSION: Anaerobic co‐digestion of FWL and PWW carried out under the optimum condition may be a feasible and efficient treatment option for methane production. Copyright © 2012 Society of Chemical Industry     

Energy requirements and production cost of the spray drying process of cheese whey

The influence of spray drying conditions on the energy required, production cost, and physicochemical characteristics of cheese whey was researched. The factors investigated were the inlet air temperature (180–220°C), outlet air temperature (80–100°C), and silica and maltodextrin (DE-10) as additives at 2 and 5% (w/w), respectively. Analysis of variance revealed that the inlet and outlet air temperatures, and the addition of additives had significant effects (p?T_inlet of 180°C, T_outlet of 80°C, and the addition of 5% additive material. Under these conditions, 0.2165?kg/h of dried product was obtained, with a moisture content of 2.08% and water activity of 0.125, and the product cost was $17.06?kg with an energy consumption of 2.0490?kW?·?h/kg of dry product.     

电石法PVC企业的成本分析和发展思路

分析了国内电石法PVC企业的生产成本情况,指出了影响成本的主要因素,并提出了发展思路。     

Effects of chemical and thermochemical pretreatments on sunflower oil cake in biochemical methane potential assays

BACKGROUND: The effects of chemical and thermochemical pretreatments on the composition and anaerobic biodegradability of sunflower oil cake were studied to compare these pretreatments and to assess their effectiveness. Four reagents (lime, sodium hydroxide, sulphuric acid, and sodium bicarbonate) at concentrations of 25% (w/w) of dry weight of substrate and 20 g L^?1 substrate concentration were used for the chemical pretreatment for 4 h. The same conditions were used for thermochemical pretreatment with heating at 75°C. After the pretreatments, the solid and liquid fractions were separated and subjected to biochemical methane potential tests. RESULTS: The methane yields of the solid fraction obtained with lime, sodium hydroxide, sulphuric acid and bicarbonate were 130±9, 54±4, 61±6 and 88±7 mL CH₄ g^‐1COD_added, respectively, and after thermochemical pretreatment were 26±2, 84±7, 74±7, and 77±6 mL CH₄ g^‐1COD_added, respectively. The methane yields for liquids were 152±13, 2±0, 0±0, 249±19 mL CH₄ g^‐1COD_added, for the chemical pre‐treatment, respectively, and after the thermochemical pretreatment were 273±13, 58±5, 0±0 and 145±12 mL CH₄ g^‐1COD_added, respectively. CONCLUSION: Only the solid fraction obtained after the chemical pretreatment with lime gave a methane yield higher (130 mL CH₄ g^‐1COD_added) than the obtained for the untreated solid material (114 mL CH₄ g^‐1COD_add). No thermochemical pretreatment enhanced the methane yield of the solid or liquid fractions of the untreated material. © 2012 Society of Chemical Industry     

A new targeting method for estimation of cogeneration potential and total annualized cost in process industries

One of the important tasks for optimal design and analyses of site utility systems is targeting total annualized cost and cogeneration potential. This paper introduced a new cogeneration and total annualized cost (TAC) targeting models that were developed to estimate the cogeneration potential of site utility systems and total annualized cost. The procedure which was proposed here provided a consistent, general procedure for determining mass flowrates and efficiencies of the applied turbines. This algorithm utilized the relationship of the entropy with the enthalpy and the isentropic efficiency. It is considered superior to previous works in that it was accurate, did not require any cumbersome simulation for initiation and could be easily traced,which enhance its programmability, considering full lifetime of the utility prices and it can estimate TAC and TASP with diffrent cost functions. Also, the developed model based on the trends of historical prices has been considered for estimation of utility costs.     

抓住机遇 科学发展--从当前硫铁矿与硫磺制酸的成本比较看我国硫铁矿制酸的发展机遇

对当前硫铁矿与硫磺制酸生产成本进行分析与比较。由于硫磺价格的上扬,硫铁矿制酸生产成本低100元／t左右。据此指出我国硫铁矿制酸企业应当珍惜并抓住当前的机遇,科学发展,加快发展,通过一些措施,如大型化,提高热利用率,开发延伸产品等,提高硫铁矿制酸企业的竞争力。呼吁走可持续发展道路,打造我国硫酸产业的循环经济。     

Ontogenic development of chemical defense by seedling resin birch: Energy cost of defense production

Whether production of chemical defenses by plants is or is not an energetically costly process is an important, but unresolved, question in chemical ecology. We suggest studies of the ontogenetic development of plant defense systems can help resolve the question. As an example of this approach to the cost question, we explore the problems associated with production of immobile chemical defenses that defend juvenile resin birches against browsing by mammals. From this exploration we draw two conclusions: (1) Shortly after germination, production of chemical defenses by small-seeded species, such as birch, is energetically costly. (2) Opposing selection for defense versus competitive ability in the seedling stage of birch has resulted in a trade-off in allocation of carbon to production of immobile chemical defense versus allocation of carbon to production of storage reserves. We suggest this trade-off results in a large indirect cost of defense because carbon used for production of immobile chemical defenses is unavailable for support of growth in the future, but stored carbon can be used to support future growth.