Abstract: A vaporizer including injection lances disposed within a vessel for injecting a substance such as liquid or heating media, into the vessel. The lances are configured for removal from the vessel through at least one of multiple orifices in the wall of the vessel. The orifices are configured to have lances extending through them into the vessel. The configuration of the vaporizer facilitates performing maintenance or making changes to the lances without the need to take the vaporizer out of service.

Abstract: A selective catalytic reduction (SCR) system is defined that uses the measured concentration of reactant slip in the exhaust gas after SCR processing to control the amount of reactant injected during non-steady-state operational conditions. The SCR system works with a reactant slip detector located in the post-SCR processing section of the exhaust flue. The reactant slip detector measures the concentration of reactant in the exhaust gases and, based on that concentration, the amount of reactant injected into the pre-SCR processing exhaust gases is controlled.