For more efficient utilization of coke oven gas (COG), a byproduct from the production of metallurgical cokes, a reforming technology of hot COG (HCOG) was developed to obtain material gases suitable for methanol production. A test plant was installed on a platform of an operating coke oven. HCOG was fed into a tubular reactor (0.6 m i.d. and 3.2 m long) at flow rates from 28 to 103 Nm3/h and was partially oxidized by injecting O2 (from 12 to 30 Nm3/h) from nozzles near the inlet. Exhaustive test runs identified the appropriate reforming conditions required to achieve more than 2.2-fold syngas amplifications, and the optimum product gas composition for methanol synthesis. Numerical simulations using detailed chemical kinetics coupled with a plug-flow reactor model were also conducted. The kinetic model developed by Richter and Howard [Phys. Chem. Chem. Phys. 2002, 4, 2038−2055] including 257 chemical species and 2216 elementary steplike reactions was used. HCOG was modeled as a multicomponent gas mixture involving H2, CO, CO2, CH4, C2 hydrocarbons, H2O, and 31 aromatic hydrocarbons such as benzene and toluene, as well as polycyclic aromatic hydrocarbons up to coronene, to represent the HCOG tar. Satisfactory agreement was observed in comparisons between the predictions from the numerical simulations and the data measured from the 20 test runs, indicating that the model can be a promising tool toward designing a demonstration/commercial HCOG reforming plant.

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Abstract— The fracture behaviour of high strength steels under the influence of hydrogen was studied, with special emphasis on the critical condition for the formation of intergranular (IG) cracks. Mechanical tests were carried out on cathodically charged specimens subjected to both a constant load and a constant displacement under a variety of hydrogen‐charging conditions. Experimental analyses show that a high local hydrogen concentration plus a high stress intensity at a quasi‐cleavage (QC) crack tip are required to initiate intergranular cracking. The condition for continued intergranular crack propagation, leading to micro‐void coalescence (MVC), is determined by the combined effect of the speed of crack propagation together with the rate of hydrogen diffusion. A quasi‐cleavage crack triggers the onset of intergranular crack growth irrespective of the test control parameters, i.e. constant loading or constant displacement conditions. A fracture map is proposed relating to the boundary conditions between QC, IG and MVC cracking, which will assist further research.

To comprehensively investigate the tensile properties of cold bends, full-scale cold bending experiments, tensile tests using prestrained small-scale specimens, and finite element (FE) analyses of the cold bending processes were conducted on API 5L X60 and X80 grade line pipes. The tensile tests revealed that the tensile properties of the cold bends were comparable to the uniaxially prestrained specimens machined from the straight part of the pipes. A FE model simulating the cold bending process was verified with the full-scale experimental results in terms of the distributions of residual strains. These results supported a procedure for estimating the tensile properties of the cold bends with a combination of the FE model and the tensile tests using the prestrained specimens; the residual strains obtained from the FE model are transformed into the tensile properties based on the relationship between the residual strains and the tensile properties. This study clarified that the tensile properties come close to being uniformly distributed by reducing the distance between the bending locations; the distance between the bending locations has a significant influence on the overlap of adjacent deformed areas, which governs the distribution of the tensile properties of the cold bends.

The large deformation behavior of cold bend was experimentally and analytically investigated. Full-scale large deformation experiments were conducted on two API X80 grade cold bends with a bending angle of approximately 9 degrees for both closing and opening modes. Finite element (FE) analyses were also conducted to simulate the large deformation behavior by considering the distribution of tensile properties after the cold bending process. The results of the simulation were in good agreement with the large deformation experiments. The deformability of cold bend in the opening mode was greater than that in the closing mode. Changes in the tensile properties due to the cold bending process had a large influence on the deformability of cold bend. In particular, distribution of the part with work hardening after the cold bending process had large effect on the deformability in the closing mode.