Study On On-line Ash Deposition And Scaling Monitoring And Sootblowing Optimization On Tubular-furnace Convection Surface

The ash deposition or the scaling of convective heating surface is an important factor of the safe of tubular-furnace and efficient running. But sootblowing is the most effective and common method to solve this problem. Without on-line fouling supervising equipment the ash blowing process has to be operated on a regular time by operator's experience, so it is not accurate. In this paper, the method for the on-line monitoring of ash deposition and scaling on continuous reforming tubular-furnace heat surfaces is put forward, and the basic principle of monitoring method is stated. And on this basis the on-line monitoring system of ash deposition and scaling is developed to guide and optimize the process of sootblowing.The researches about the ash fouling monitoring technique and models of tubular-furnace are analyzed and summarized. By the measurable parameters of the process of tubular-furnace, practical conduct coefficient and ideal conduct coefficient of convective heating surface of tubular-furnace in calculating model are combined. So the on-line monitoring models of convective heating surface in tubular-furnace, waste-heat boiler and air preheater are proposed. Clean Factor(CF) is chosen to express the effect of ash fouling on the heat transfer.On the base of the on-line monitoring data of convective heating surface fouling, the calculating model of sootblowing optimization is educed. Then according to the principle, which the sum of the loss cost of energy what steam soot-blower consume, the loss cost of energy of gathering soot and the loss cost of energy furnace system is least, the optimization time-interval of sootblowing is confirmed.Grounded on the existing research and operation level of the soot-blower, the fouling on-line monitoring and sootblowing optimization system of tubular-furnace are designed, which include data communicating module, data management module, fouling monitoring module, sootblowing optimization module and sootblowing automatic control module. It is focused on the design of software and hardware of PCBCS. This paper also presents communication implementation based on Modbus protocol between PCBCS and DCS. The results of practical application show that the control system is stable and dependable, which is basically meets the need of automatic optimization sootblowing and monitoring. So it is helpful to the alteration of optimization sootblowing and monitor for tubular-furnace.