The rising cost of energy has prompted renewed interest in energy conservation. A small group of energy intensive industries use a disproportionate share of total delivered industrial energy consumption relative to its contribution to industrial output. These energy intensive industries include the chemical, pavement (concrete and asphalt), and paper industries. Researchers at the URI are actively involved with efforts to conserve energy in all three of these areas.
Energy use in the chemical industries is dominated by the cost of separation, particularly distillation. There are an estimated 40,000 distillation columns in the U.S. that consume approximately 18% of all of the energy in the manufacturing sector and recent estimates put this use at 2.4 quadrillion Btu/yr. This is a staggering amount. However, distillation remains the most versatile means of separation and thus will continue to be used in some capacity to address a wide variety of separation needs. Other current separation techniques simply are not competitive in terms of both volume produced and purity of product.
New synthesis and design methodologies for overall energy efficiency must not, in our opinion, dismiss energy needs associated with distillation but rather extend the current knowledge base for finding minimum energy requirements in separations to processes involving multiple units.
This is the approach adopted in Professor Lucia's research group in their efforts on energy efficient chemical process design, which is currently supported by the National Science Foundation.
Reclaimed asphalt pavement (RAP) and other solid waste materials can be used as an aggregate in the hot and cold recycling of asphalt paving mixtures. There are two different cold recycling methods. The first method (cold mix plant recycling) involves a process in which RAP is combined with new emulsified or foamed asphalt and a recycling or rejuvenating agent, possibly also with virgin aggregate, and mixed at a central plant or a mobile plant to produce cold mix base mixtures. The second, more common, method involves a process in which the asphalt pavement is recycled in-place (cold in-place recycling (CIR) process), where the RAP is combined without heat and with new emulsified or foamed asphalt and/or a recycling or rejuvenating agent, possibly also with virgin aggregate, and mixed at the pavement site, at either partial depth or full depth, to produce a new cold mix end product. Most states have used CIR in conjunction with a hot mix overlay or chip seal. When recycling techniques are utilized properly, energy consumption can be significantly decreased. Various research projects utilizing industry and construction waste materials, including recycling asphalt concrete, are ongoing. Those materials include oil spill cleanup debris, vinyl remnant, crumb rubber and reclaimed asphalt concrete, etc. Production of asphalt concrete requires heating the binder and mineral aggregates at high temperature, i.e., 300oF and above. Thus, Professor Lee's group has been investigating how we can conserve energy through utilizing those recycling and solid waste materials in building the transportation and civil infrastructure and system at lower temperature and less heating.
The production of paper requires heat to remove the residual water from pulp. However, the evaporation process must be conducted in a highly uniform fashion to generate high quality paper. Thermal inhomogeneity in paper manufacturing results in a loss of 10-15 % of the final product due to reduced paper quality. Professor Lucht and Professor Euler have been working collaboratively with Albany International, one of the leading producers of textiles for the paper manufacturing industry, to develop thermochromic carpets. These thermochromic carpets allow for the visual determination of temperature uniformity during the heating process which will allow for improvements in temperature uniformity.
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