New methods of electricity generation using steam from waste heat boilers fired by waste gases from high-temperature plants in ferrous metallurgy

Abstract

Currently, the thermal energy of the steam generated by the heat recovery steam generator (HRSG) of high-temperature ferrous metallurgy units is used practically only for space heating and hot water supply. In this regard, the consumption of heat energy is unstable during the day and over the seasons and, as a rule, much less steam is consumed than is generated. This is because HRSGs are an integral part of high-temperature installations. They provide primary dedusting and pre-cooling of waste gases, which is necessary for the operation of filters. Then these combustible gases are used as energy carriers and are sent to gas pipeline networks. As a result, steam is generally not used efficiently. The steam generated by most HRSGs is not superheated and has a high moisture content, which makes it difficult to use this steam in steam turbines. However, even in the case of superheated steam, its low volumetric flow rate makes the use of steam turbines impractical due to the low efficiency of low-power turbines. This article will discuss the possibility of using a steam-piston engine to generate electricity from steam generated by the HRSG and evaporative cooling systems. In contrast to the classic reciprocating steam engines, the steam-piston engines have a relatively high rotational speed. As a result, they are smaller and can be connected directly to modern power generators with a 1500 rpm speed. Such engines can be manufactured by converting serial internal combustion engines, which significantly reduces their cost and provides a short payback period for such equipment.