Tar Binder Research Articles

Evaluation and modelling of polycyclic aromatic hydrocarbon (PAH) bioavailability in soils affected by coal tar asphalt

There are large masses of coal tar asphalt present in old roads, containing high concentrations of polycyclic aromatic hydrocarbons (PAHs). Uncertainty surrounding the risk they pose causes problems during road reconstruction and for the reuse of the asphalt present. To help elucidate potential risks, a parsimonious linear equilibrium partitioning model for the bioavailability of PAHs in soils contaminated by tar asphalt particles was developed. Furthermore, a set of partitioning coefficients for PAHs between sampled coal tar binders and water were determined experimentally, as well as measurements of freely dissolved concentrations using polyoxymethylene samplers in batch tests and column recirculation experiments with various mixtures of different soils (peat and sandy loam) and tar asphalts. The model predictions of freely dissolved concentrations were conservative and within an order of magnitude of measurements in both batch and column tests. The model presented here only relies on soil organic carbon content and the fraction coal tar binder in the soil to model PAH partitioning. This model could be used for more realistic. Low tier risk assessments towards rational prioritization of sensitive areas for risk reduction efforts.

Development of a Binder Manufacturing Process for Molded Coal Utilizing Used Plastics

Molded coal charging process into coke oven has been used to improve coal charging density. Molded coal charging process can improve coke strength even if the rank of blended coal is low. However, the molded coal is quite expensive because the cost of coal tar binder is high. Thus, we developed a new process that could reduce the amount of tar binder by utilizing used plastics. In this new process, used plastics were charged into heavy tar and dissolved at 200ºC. The resulting binder with plastics could improve the strength of the molded coal, thus, coke was prepared experimentally using molded coal with the new binder.

Effect of heat treatment on desulphurization of petroleum coke

Calcined petroleum coke (CPC) is one of major constituent used for making graphite electrodes. Increasing demand of graphite electrodes requires more and more quantity of high quality-low sulphur calcined petroleum coke. The sulphur content of the petroleum coke strongly depends on the nature of the coking feed stock (crude oil) and its sulphur content. High sulphur coke (>1%) is not desirable for making graphite electrodes because evolution of sulphur causes puffing in the temperature range of 1,400-2,200 °C during graphitization. In this study, attempt has been made to reduce the sulphur of calcined petroleum coke by heat treatment to the acceptable level for making graphite electrodes. A high sulphur coke (approx. 2%) was heat treated up to 1,800 °C in inert atmosphere in order to reduce the sulphur content. It was observed that most of the sulphur goes off up to 1,800 °C. A sample of size 12x80 mm was prepared (by extrusion method) from desulphurized petroleum coke using coal tar binder pitch as binder at 125 °C. The extruded samples were carbonized at 900 °C, followed by graphitization at 2,900 °C. The graphitized rods were characterized for various properties such as apparent density (AD), electrical resistivity (ER), flexural strength (FS) and compared with the properties of samples made from electrode grade CPC.

Unveiling RNA‐Binding Properties of Verapamil and Preparation of New Derivatives as Inhibitors of HIV‐1 Tat‐TAR Interaction

AbstractTargeting RNA using small molecules is now established as a very promising strategy for many therapeutic applications since coding and non‐coding RNAs bear a pivotal role both in viral and bacterial infections as well as in diseases such as cancer. Here, we focused on HIV‐1 TAR RNA as a promising target for the development of new anti‐HIV therapies but also as an ideal model to validate the discovery of original RNA ligands. First, we performed an initial screening of a library of compounds against TAR that led to the discovery of verapamil, a marketed calcium‐channel blocker, as a promising chemical structure for the development of new RNA ligands. The synthesis of a series of analogs of verapamil led to promising structure activity relationships and to the discovery of a conjugate between verapamil and an indole fragment, as an efficient and selective TAR binder able to inhibit Tat/TAR interaction with an IC50 of 18.8 μM. This work supports the potential of library screening for the discovery of original and selective RNA ligands and illustrates how existing drugs directed against protein targets still need to be studied for RNA binding as a promising strategy in the field of RNA targeting by small molecules.

Development of a Binder Manufacturing Process for Molded Coal Utilizing Used Plastics

Molded coal charging process into coke oven has been used to improve coal charging density. Molded coal charging process can improve coke strength even if the rank of blended coal is low. However, the molded coal is quite expensive because the cost of coal tar binder is high. Thus, we developed a new process that could reduce the amount of tar binder by utilizing used plastics. In this new process, used plastics were charged into heavy tar and dissolved at 200°C. The resulting binder with plastics could improve the strength of the molded coal, thus, coke was prepared experimentally using molded coal with the new binder.

Superior HIV-1 TAR Binders with Conformationally Constrained R52 Arginine Mimics in the Tat(48-57) Peptide.

We report a 100-fold increase in binding affinity of the Tat(48-57) peptide to HIV-1 transcriptional activator-responsive element (TAR) RNA by replacing Arg52, an essential and critical residue for Tat's specific binding, with (2S,4S)-4-guanidinoproline. The resulting αTat1M peptide is a far superior binder than γTat1M, a peptide containing another conformationally constrained arginine mimic, (2S,4S)-4-amino-N-(3-guanidinopropyl)proline, or even the control Tat peptide (CtrlTat) itself. Our observations are supported by circular dichroism (CD), isothermal titration calorimetry (ITC), gel electrophoresis and UV spectroscopy studies. Molecular dynamics simulations suggest increased interactions between the more compact αTat1M and TAR RNA, relative to CtrlTat. The CD signature of the RNA itself remains largely unchanged upon binding of the peptides. The Tat mimetics further have better cell uptake properties than the control Tat peptide, thus increasing their potential application as specific TAR-binding molecules.

Preparation of micro-porous monolithic activated carbon from anthracite coal using coal tar pitch as binder

Monolithic activated carbon (MAC) has been produced from steam activation of monoliths prepared by mixing coal powders with high-temperature coal tar binder for a long time. However, this process leads to poor working conditions, environmental pollution, and waste of resource. This study investigated the use of coal tar pitch as binder to prepare MAC with high surface area, micro-pore structures, and strong mechanical strength. The performances of the MACs with both coal tar and coal tar pitch as binders were compared. The product yield of MAC bonded with coal tar pitch (MACp) was 10% higher than that with coal tar (MACT). The BET surface area, micropore volume, and average pore diameter of MACP were 837.99 m2 g−1, 0.346 m3 g−1, and 1.776 nm, respectively, which were all superior to the corresponding values of MACT. Only the attrition resistance strength of MACP was slightly lower than that of the MACT. The SEM images showed that the cokes on the surface of both MACs distributed identically and uniformly. Furthermore, XRD results revealed that the pore-expanding reactions mainly led to the reduction of carbon crystallite along with the stacking direction rather than horizontal direction during steam activation process. This work demonstrates that cost-effective MAC can be prepared with the coal tar pitch as binder and the results of the investigation presented in this work provide new and important information necessary to the successful application of MACs in industrial field.

Design, synthesis and biological evaluation of TAR and cTAR binders as HIV-1 nucleocapsid inhibitors

We designed, synthesized and tested novel 2,6-disubstituted-anthraquinones able to bind dynamic secondary structures of nucleic acids, such as TAR RNA and its reverse transcript cTAR, leading to inhibition of the chaperone activities of the nucleocapsid NCp7, a highly conserved viral protein implied in crucial steps of HIV-1 replication.

Effect of short oil‐length alkyd additive on the properties of coal tar binder

Purpose – Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend technique is a simple and useful method for improving paint properties. Coal tar resins are the most economical coating extensively used in the industry; short oil‐length alkyd resins are usually used for air and force‐dry industrial coatings for metal surfaces. The purpose of this paper is to evaluate coating blends composed of these resins, in particular, the effects of short oil‐length alkyd additive on the properties of coal tar binder.Design/methodology/approach – One way to achieve new types of binders is to make combinations of the existing ones, in an ideal case retaining the desirable properties of both. The alkyd has important properties over the original drying oil. To achieve the goal of improving coal tar resin properties, short oil‐length alkyd was blended with it. The prepared short oil‐length alkyd was charac...

Heat-treated limestone-periclase ladle components with tar binder

Heat-treated limestone-periclase ladle components with tar binder

Evaluation of carbon materials for use in a direct carbon fuel cell

The direct carbon fuel cell (DCFC) employs a process by which carbon is converted to electricity, without the need for combustion or gasification. The operation of the DCFC is investigated with a variety of solid carbons from several sources including some derived from coal. The highly organized carbon form, graphite, is used as the benchmark because of its availability and stability. Another carbon form, which is produced at West Virginia University (WVU), uses different mixtures of solvent extracted carbon ore (SECO) and petroleum coke. The SECO is derived from coal and both this and the petroleum coke are low in ash, sulfur, and volatiles. Compared to graphite, the SECO is a less-ordered form of carbon. In addition, GrafTech, Inc. (Cleveland, OH) supplied a well-fabricated baked carbon rod derived from petroleum coke and conventional coal–tar binder. The open-circuit voltage of the SECO rod reaches a maximum of 1.044 V while the baked and graphite rods only reach 0.972 V and 0.788 V, respectively. With this particular cell design, typical power densities were in the range of 0.02–0.08 W cm −2, while current densities were between 30 and 230 mA cm −2. It was found that the graphite rod provided stable operation and remained intact during multi-hour test runs. However, the baked (i.e., non-graphitized) rods failed after a few hours due to selective attack and reaction of the binder component.

Selection of TAR RNA-binding chameleon peptides by using a retroviral replication system.

The interaction between the arginine-rich motif (ARM) of the human immunodeficiency virus (HIV) Tat protein and TAR RNA is essential for Tat activation and viral replication. Two related lentiviruses, bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV), also require Tat ARM-TAR interactions to mediate activation, but the viruses have evolved different RNA-binding strategies. Interestingly, the JDV ARM can act as a "chameleon," adopting both the HIV and BIV TAR binding modes. To examine how RNA-protein interactions may evolve in a viral context and possibly to identify peptides that recognize HIV TAR in novel ways, we devised a retroviral system based on HIV replication to amplify and select for RNA binders. We constructed a combinatorial peptide library based on the BIV Tat ARM and identified peptides that, like the JDV Tat ARM, also function through HIV TAR, revealing unexpected sequence characteristics of an RNA-binding chameleon. The results suggest that a retroviral screening approach may help identify high-affinity TAR binders and may provide new insights into the evolution of RNA-protein interactions.

Improving form coke briquette strength

Formcoke technology, which involves briquetting of char, coke and/or raw coals with a binder material, permits the use of a wide range of coals as the feedstock. This technology aims to produce a fuel that possesses properties similar to those of conventional coke. In addition to a high calorific value and fixed carbon content, the major physical requirement is that the formcoke must retain its shape and form during shipping and storage, as well as exposure to heat in a furnace. The major objective of this study was to determine the conditions that could provide high compressive strengths [in excess of 2.8×10 7 Pa (4000 psi)] for piston formcoke briquettes prepared without air-curing green briquettes in the FMCoke process. The effect of the thermal pretreatment of the binder on compressive strength of briquettes was examined. In addition, novel methods to promote stronger bonds at the binder/ calcinate interface were explored. The addition of liquid phase oxidants (for example, hydrogen peroxide, among others) to coal tar binders was examined to promote in situ release of oxygen during curing under an inert environment. This release of oxygen, simulating the presence of air in the curing environment, was expected to promote stronger interfacial bonds between the binder and the calcinate. Modification of the binder/ calcinate interface was also examined through use of minor quantities of other types of additives. In particular, the addition of phosphoric acid to the calcinate delivered piston briquettes with compressive strength readily exceeding 2.8×10 7 Pa without recourse to air-curing. Curing in air, in fact, led to compressive strengths exceeding 5.5×10 7 Pa.

Carbon Adsorbents from Petroleum Binders

A method for enhancing the adsorption capacity of previously obtained [1] adsorbents by altering their charge composition is described. The structures and properties of the adsorbents molded with conventional wood tar and petroleum binders are compared. Scarcity of wood tar is restraining production growth and broadening of range of carbon adsorbents.

The effect of binders and agricultural by-products on physical and chemical properties of granular activated carbons

Four binders (coal tar, sugarcane molasses, sugar beet molasses, corn syrup) were mixed with three agricultural by-products (rice hulls, rice straw, sugarcane bagasse) in different combinations and these mixtures transformed into granular activated carbons (GACs). GACs were evaluated for the physical properties of burn-off/yield, surface area, bulk density and hardness and the chemical properties of pH and ash. These properties, except for burn-off/yield, were compared to the same properties of two commercial reference carbons made from bituminous coal with coal tar binder. The results show that GACs made with corn syrup as binder exhibited surface areas, bulk densities, hardness, pH and ash values closest to the reference carbons. The presence of a specific by-product appeared less important than the presence of a specific binder in determining the physical and chemical characteristics of the GACs.

98/00346 Production of activated carbon from coal and tar binder

98/00346 Production of activated carbon from coal and tar binder

96/03561 New materials by aggiomeration of petroleum coke fines

Formcoke technology, which involves briquetting of char, coke and/or raw coals with a binder material, permits the use of a wide range of coals as the feedstock. This technology aims to produce a fuel that possesses properties similar to those of conventional coke. In addition to a high calorific value and fixed carbon content, the major physical requirement is that the formcoke must retain its shape and form during shipping and storage, as well as exposure to heat in a furnace.The major objective of this study was to determine the conditions that could provide high compressive strengths [in excess of 2.8×107 Pa (4000 psi)] for piston formcoke briquettes prepared without air-curing green briquettes in the FMCoke process. The effect of the thermal pretreatment of the binder on compressive strength of briquettes was examined. In addition, novel methods to promote stronger bonds at the binder/calcinate interface were explored. The addition of liquid phase oxidants (for example, hydrogen peroxide, among others) to coal tar binders was examined to promote in situ release of oxygen during curing under an inert environment. This release of oxygen, simulating the presence of air in the curing environment, was expected to promote stronger interfacial bonds between the binder and the calcinate. Modification of the binder/calcinate interface was also examined through use of minor quantities of other types of additives. In particular, the addition of phosphoric acid to the calcinate delivered piston briquettes with compressive strength readily exceeding 2.8×107 Pa without recourse to air-curing. Curing in air, in fact, led to compressive strengths exceeding 5.5×107 Pa.

95/03577 Reforming of tar or pitch binders for formed coke

95/03577 Reforming of tar or pitch binders for formed coke

The influence of primary quinoline insolubles on the development of secondary quinoline insolubles in coal tar pitches

The development of secondary quinoline insolubles (2°QI) or mesophase has been studied by heat treating four different, commercially available coal tar binder pitches to a series of predetermined temperatures and hold times. The development of the 2°QI is discussed in terms of the shape and amount of the primary quinoline insolubles (1°QI) initially present in each pitch by examination of scanning electron micrographs of the extracted quinoline insolubles. The development of the 2°QI of these materials is compared with the development of 2°QI in a petroleum pitch where 1°QI is initially absent. Small, laboratory extruded graphite rods using each of the four binder pitches were produced in order to examine the influence of 2°QI development on typical graphite properties.

A general theoretically derived equation for the coke yield in liquid phase pyrolysis

The coke yield (CY) in liquid phase pyrolysis can be described by the following theoretically derived equation: CY = CY max − C · h o −1 · −0.5 This equation is based on the evaporation kinetics of volatile products. It shows that the coke yield is proportional to the reciprocal initial filling height of the reactor tube h o and also proportional to the reciprocal square root of the pressure p. For an investigated coal tar binder pitch with a softening point of 85°C (KRÄMER-SARNOW), the following relationship was obtained: CY = 90 − 15 · h o −1 · p −0.5