Pinch Analysis of a Partly Integrated Pulp and Paper Mill

The pulp and paper industry, with its wood biomass feedstock, has promising opportunities to becomea key player in the biorefinery arena. A successful implementation of biorefinery pathways requires optimizationof the energy system through process integration, and can lead to both increased and diversified revenues as wellas a reduction of global CO2 emissions. This paper presents the results from a pinch analysis of a partlyintegrated Kraft pulp and paper mill. The objective was to identify the potential for energy efficiencyimprovements, focusing on possibilities to save steam. Another objective was to identify practical retrofitsolutions for the mill heat exchanger network and to estimate the costs for the required investments. Thepotential for energy savings at the mill is estimated at 18.5 MW, i.e. 12% of the current steam demand. Two alternative retrofit options are presented in the paper. A straightforward retrofit that is easy to implement enables5.8 MW of steam to be saved at a cost of €0.13 million per MW of saved steam. A second more extensive retrofit option is also presented which could achieve steam savings of 11 MW at a cost of €0.14 million per MW of saved steam. Assuming that the steam savings lead to a reduced use of bark fuel in the power boiler, the payback period of both energy saving retrofit investments is estimated to be less than about 16 months

I. Idempotent Multipliers of H¹ on the Circle. II. A Mean Oscillation Inequality for Rearrangements

H1(T) is the space of integrable functions f on the circle T such that the Fourier coefficients f&#x0302;(n) vanish for negative integers n. A multiplier is by definition a map m of H1 to itself such that the Fourier transform diagonal izes m. Let m&#x0302;(n) denote the diagonal coefficients of m for nonnegative n. Then m is called idempotent if each coefficient is zero or one. Theorem: If m is idempotent, then the set of n for which m&#x0302;(n) = 1 is a finite Boolean combination of sets of nonnegative integers of the following three types: finite sets, arithmetic sequences, and lacunary sequences. By definition, a sequence is lacunary if there is a real number q &gt; 1 such that each term of the sequence is at least as large as q times the preceding term. The theorem implies a classification of the projections in H1 which commute with translations, or, what is equivalent on the circle (but not on the line), of the closed, translation invariant subspaces which are complemented in H1. In the course of the proof, a 1 ower bound is obtai ned on the operator norm of a multiplier whose coefficients are 0 or greater than 1 in magnitude. This bound implies that the number of nonzero coefficients in disjoint intervals of the same length is the same, up to some factor depending on the norm of m, provided that both intervals are shorter than their distance from 0. Part II is unrelated to Part I. There it is proved that a general expression measuring the oscillation of a function on an interval is minimized by the decreasing rearrangement of the function. A special case of this expression is the BMO norm for functions of bounded mean oscillation.</p

The Impact of Personalized Preventive Care on Health Care Quality, Utilization, and Expenditures

The objective of this study was to evaluate the impact on health care utilization and expenditure trends over time of a personalized preventive medicine program delivering individualized care focused on lifestyle behavior modification, disease prevention, and compliance with quality-related metrics. MD-Value in Prevention (MDVIP) is a network of affiliated primary care physicians who utilize a model of health care delivery based on an augmented physician-patient relationship and focused on personalized preventive health care. Multivariate modeling was used to control for demographics, socioeconomics, supply of health care services, and health status among 10,186 MDVIP members and randomly selected, matched nonmembers. Health care utilization and expenditure trends were tracked from the pre period prior to member enrollment for a period of up to 3 years post enrollment. MDVIP members experienced reduced utilization of emergency room and urgent care services compared to nonmembers. Program savings ranges indicated that, over time, increasing percentages of members achieved cost savings compared to nonmembers. Older age groups were more likely to realize savings in the early years with preventive activities indicating condition management, and younger age groups were most likely to achieve savings by the third year after enrollment. These results indicate that a primary care model based on an enhanced physician-patient relationship and focused on quality and personalized preventive care within a time frame of 3 years can achieve positive health care expenditure outcomes and improved health management.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140194/1/pop.2015.0171.pd

Pre- and post-treatment assessment for the anaerobic digestion of lignocellulosic waste: P-graph

Lignocellulosic waste is one of the most abundant and potential feedstocks for anaerobic digestion (AD), but the energy efficiency is limited by the lignocellulosic composition which is recalcitrant to biodegradation. Pretreatment of feedstock and the post-treatment of biogas and digestate play a significant role in enhancing the AD efficiency as well as the product utilisation. This study aims to determine the cost-optimal pre-and post-treatment pathway for an AD of lignocellulosic waste by applying P-graph. The economic balance between the main operating cost, yield and quality of products were considered. The treatment options were overviewed followed by a case study considered a different combination of physical, chemical and biological pretreatments, biogas post-treatment (combine heat and power, fuel cell, biomethane, biofuel) and digestate treatments. A total of 9 pre-treatments for lignocellulosic waste, 2 digestate post-treatments and 9 post-treatments for biogas were evaluated in this study. Chemical pre-treatment by CaO, post-treatment by H2S removal with membrane separation for biomethane production and without the composting of digestate is suggested as the optimal treatment pathway for lignocellulosic waste

Lattice thermal conductivity of disordered NiPd and NiPt alloys

Numerical calculations of lattice thermal conductivity are reported for the binary alloys NiPd and NiPt. The present work is a continuation of an earlier paper by us [PRB, 72, 214207 (2005)]which had developed a theoretical framework for the calculation of configuration-averaged lattice thermal conductivity and thermal diffusivity in disordered alloys. The formulation was based on the augmented space theorem combined with a scattering diagram technique. In this paper we shall show dependence of the lattice thermal conductivity on a series of variables like phonon frequency, temperature and alloy composition. The temperature dependence of $\kappa(T)$ and its realtion to the measured thermal conductivity is discussed. The concentration dependence of $\kappa$ appears to justify the notion of a minimum thermal conductivity as discussed by Kittel, Slack and others. We also study the frequency and composition dependence of the thermal diffusivity averaged over modes. A numerical estimate of this quantity gives an idea about the location of mobility edge and the fraction of states in the frequency spectrum which is delocalized.Comment: 23 pages, 18 figure

An emissions analysis for environmentally sustainable freight transportation modes: distance and capacity

Transportation is one of the largest air pollutants as well as the Greenhouse Gas (GHGs) contributors. The inclusion of air pollutants in optimisation studies is less established than the use of CO2 and/or GHGs which are often used as an indicator of environmental sustainability. This study aims to assess environmentally sustainable alternatives for freight transportation by considering both GHG and air pollutants. A case study identifying air emissions of different freight transport modes for moving goods from Rotterdam is presented. The assessed freight transports include articulated lorry, container ship, bulk carrier, and rail operated by diesel. The environmentally sustainable freight transport of the studied route based on the common practice (GHGs only) and the inclusion of air pollutants are discussed. Evaluation of the results shows that transport with lower GHG emissions does not result on PM and SOx as well. A possibility of inappropriate decision making has been consequently highlighted. The impact of loaded capacity in moving the goods on the emission is assessed from the perspective of logistics service provider. A further comprehensive study which includes the entire life cycle is needed as this study only considers the tank to wheel emissions

Bioenergy production and nutrients removal by green microalgae with cultivation from agro-wastewater palm oil mill effluent (POME) - A review

Environmental pollution specifically wastewater is gaining attention both in the developed and developing countries. Malaysia is considered as one of the major palm oil producers in the world. Therefore, it is important to develop an environmental friendly and economic method to treat palm oil mill effluent (POME). The wastewater can serve as an economical nutrient source or substrate that can support the cultivation of microalgae. This can be a great nutrient for algal cultivation at the same time as remediating effluent and generating biomass. Nowadays, many microalgae species are being investigated to determine their potential and effectiveness for phytoremediation application, especially high growth rate. However, using synthetic media for growing microalgae in a mass scale is costly. It is acknowledged that POME (as nutrients enriched media) assisted enhanced microalgae growth under certain condition can considerably reduce the presence of organic and inorganic compounds. In this review, the potential of wide range of the predominant microalgae species with main focus on green microalgae (high removal efficiency): Chlamydomonas sp and Chlorella sp were investigated. Moreover, we discussed about the history, methods and future prospects in nutrients removal by green microalgae comprehensively. This review discusses several potential strategies for tackling the environmental issue generated by agro-waste water POME with enhancement of biomass productivity which can be used as an alternative for energy production

A review on the economic feasibility of composting for organic waste management in Asian countries

The rising rate of population growth and industrial development mainly in urban areas have led to significant increase in municipal solid waste (MSW) production. It has been a challenge to materialise a sustainable solid waste management notably in many developing countries. Organic portion represents a significant component in the municipal solid waste across countries with different level of income, ranging from about 25 to 70 %. Composting can be a viable option to manage waste sustainably by transforming waste into value-added fertiliser. Large-scale operation of composting is confronted with concern over feasible economic performance, which varied following different mode of operation. This study aims to review the economic feasibility (EF) on two different composting systems, which are the in-vessel and windrow system, implemented in several developed and developing countries. The review considered the cost factors for both composting systems, including the capital cost and operating cost. The return on investment (ROI) is estimated for both composting systems based on the potential cost benefits from the compost sale and the saving of waste tipping fee. This review provides a better insight into the desirability and applicability of both composting systems as an alternative to the landfilling practice. It is expected that the review of the various composting system could be very useful for improving the sustainable composting technology in the developing countries