A Comparison of Several Types of Enclosed Coal Storage Yards

 The fully enclosed coal storage facilities most commonly in operation at domestic coal-fired power plants include circular coal yards, linear coal yards, and dry coal sheds. This paper presents a technical and economic comparison of these three types of coal storage facilities. Enclosed circular coal yards offer higher coal storage capacity per unit area, require less land, feature a high degree of automation, and have an aesthetically pleasing appearance. However, when storing high-volatility coal, they are prone to spontaneous combustion, making fire prevention challenging. Additionally, they lack backup facilities for stacker-reclaimers and do not support functions such as segregated stacking or sun-drying; Although enclosed linear coal yards allow for segregated stacking, they occupy a large area; bucket wheel stackers and reclaimers cannot load and unload simultaneously, and they lack the ability to sun-dry the coal to control moisture content. Considering factors such as the high stickiness of the coal supplied to the project, the rainy climate, and the need for sun-drying to control moisture, the enclosed dry coal shed solution is recommended.

The fully enclosed coal yards most commonly in operation at domestic coal-fired power plants primarily include circular coal yards, linear coal yards, and dry coal sheds. Based on the current coal storage situation at the Sinochem Quanzhou Project, a technical and economic comparison of these three types of coal storage facilities is conducted, using the expansion of a coal yard with a storage capacity of 100,000 metric tons as an example. Enclosed circular coal yards offer higher coal storage capacity per unit area, require less land, feature a high degree of automation, and have an aesthetically pleasing appearance. However, when storing high-volatility coal, they are prone to spontaneous combustion, making fire prevention challenging. Additionally, they lack backup facilities for stacker-reclaimers and do not support functions such as segregated stacking or sun-drying; Although enclosed linear coal yards allow for segregated stacking, they occupy a large land area; bucket wheel stackers and reclaimers cannot load and unload simultaneously, and they lack the ability to sun-dry the coal to control moisture content. Considering factors such as the high stickiness of the coal supplied to the project, the rainy climate, and the need for sun-drying to control moisture, the enclosed dry coal shed solution is recommended.

Sinochem Quanzhou Petrochemical Co., Ltd. (hereinafter referred to as Sinochem Quanzhou) was established in September 2006 as a wholly-owned subsidiary of Sinochem Group. It is located in the Quanhui Petrochemical Industrial Park within the Meizhou Bay Petrochemical Base in Fujian Province. The 12 million metric tons per annum oil refining project, which has been completed and put into operation, is a key national construction project under the 12th Five-Year Plan. It includes more than 20 production units, as well as supporting oil storage and transportation facilities, utility systems, a 300,000-metric-ton crude oil terminal, and refined oil terminal facilities.

The Sinochem Quanzhou Petrochemical Power Station consists of a Phase I power station and a Phase II power center. Phase I comprises 2 × 310 metric tons per hour CFB boilers and 2 × CC50 MW double-extraction, condensing steam turbine generator sets, while Phase II comprises 3 × 480 t/h CFB boilers plus 2 × CB50 MW extraction-backpressure steam turbine generator units.

2.1 Current Coal Storage Status

The primary fuels for this project’s power center are coal and petroleum coke. The Phase I power plant has constructed four dry coal sheds, each with a span of 30 m and a length of 126 m, with a total storage capacity of approximately 50,000 t, sufficient to meet the fuel requirements of the Phase I power plant for about 30 days; The Phase II Power Center has constructed a circular coal yard with a diameter of 90 m and a retaining wall height of 20 m. Its theoretical design storage capacity is approximately 90,000 metric tons, while the actual storage volume is about 60,000 metric tons, sufficient to meet the fuel demand of the Phase II Power Center for approximately 15 days.

2.2 Reasons for the Retrofit

The project’s primary fuels are high-sulfur petroleum coke and fuel coal; Coal is transported to the plant via waterways using bulk cargo ships. During the rainy and typhoon seasons, moisture levels in the coal increase significantly during transit, with external moisture content exceeding 8% to 10%. This gradually deteriorates the coal’s flowability, leading to blockages in various feeding system equipment, coal hoppers, and chutes, making coal feeding difficult and causing the feeding system to become paralyzed and uncontrollable.

Given the adverse weather conditions in Fujian Province, the unpredictability of coal transportation at the docks, and the susceptibility of equipment along the unloading route to malfunctions—all of which can easily lead to a passive situation where coal supply becomes difficult—there is an urgent need to increase on-site coal storage capacity and flexibly adjust the volume of coal stored on-site to cope with market fluctuations in coal prices and enhance economic efficiency.

For specific solutions, see the article “Comparison of Several Types of Enclosed Coal Yards (1).”