This paper introduces the main problems existing in the domestic low pressure steam system of large-scale iron and steel enterprises.Based on the analysis of the system structure of low pressure steam,the mathematical models of the different steam producers are developed and the optimal regulation model(improved simplex linear programming) is set up to get the optimal way.In addition,this paper takes one iron and steel enterprise as an example and does an empirical research on the result of the optimal model.Large energy-saving potential could be achieved by the optimal operational planning.

Nowadays, as a key energy-saving promotion project, the technology of Coke Dry Quenching (CDQ) is a highlight in the metallurgical industry and coking plants, which has favorable social and economical benefits. The development of metallurgical industry is restricted by some industrial policies, such as energy-saving consumption, reducing the cost, increasing the ability of electricity self-supply, and protecting the environment, and so on. The Chinese government requires recovery more waste heat and generate more electricity during the CDQ process. Medium-pressure CDQ boiler, being an important part of the CDQ system, could not meet the increasing energy demands so far. Thus, the investigation of the high temperature and high pressure waste-heat boiler of natural circulation in the CDQ system becomes one of the vital topics.According to the process characteristics of coke drying quenching (CDQ) system, this paper gives the structure arrangement and heat distribution of the heating surfaces of the natural circulation CDQ waste-heat boiler with high pressure and high temperature, which guarantee the water natural circulation in a secure and reliable way. In addition, thermal parameters are also analyzed referring to the operating experiences in CDQ boiler research. Besides, the calculation manner of the additional heating surface including water wall is presented. Finally, the difficulties and the corresponding measures that should be taken in the boiler design are discussed. Different design schemes are given and compared according to the difficulties, and an optimal scheme is presented in this paper. This study provides a reference for the design and development of the natural circulation CDQ boilers with high pressure and high temperature.

According to the process characteristic of coke drying quenching(CDQ) system,taking the safety into consideration,gives the arrangement of high-pressure heat exchangers in natural circulation exhaust-heat boiler,and the distribution ratio of the heat quality and other thermal parameters are also analysed referring to the running experience in CDQ boiler research.Some bases on advanced design and development for CDQ natural circulation boilers have also been offered in the passage.

In this paper,the feasiblity study on using the lithium bromide steam refrigeration to increase the summer steam load is made for solving the problem of massive steam loss in low pressure steam system.Through the comparison of the calculation of the thermal parameters using the lithium bromide steam refrigeration instead of the electrical refrigeration,it can be found that it realizes heat and power combining with cooling.This enhances the economy of the heat supplying and reduces the steam loss and the difference of the electrical net peak and valley as well.The aim of electricity saving,energy saving and environmental pollution reduction can therefore be realized in BAOSTEEL.