China grain project

by Teresa Acklin
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China adapting to new storage and handling technologies as massive development of its grain infrastructure proceeds.

   Signs have emerged that predictions of grain shortages in China are beginning to be realized as the country becomes an importer of maize and imposes restrictions on grain exports. A widely publicized report by Worldwatch predicts that China's demand for grain, particularly feed grain, will increase so rapidly over the next 25 years that the world's grain trade and price structures will be drastically affected. But some observers discount these predictions, stating that economic factors will regulate Chinese dietary habits to meet the changing situation.

   But there is no doubt that the consumption of meat in China is increasing rapidly as the population's spending power increases, as has happened (or is happening) in all countries in the Asian region. This is resulting in a dramatic shift in the patterns of grain consumption, particularly in relation to maize.

   Another recently released study foreshadows the need for a major development of China's grain storage and transportation infrastructure over the next 20 years to meet the expected demand. The first phase of such development is already under way in the form of the World Bank's China Grain Distribution and Marketing Project (G.D.M.P.).

   The G.D.M.P. project is the largest World Bank project undertaken in China and the second largest project funded by the World Bank. It is without doubt the largest grain storage and handling project ever undertaken in the world. By any measure, it is a big project, with a budget of just under U.S.$1 billion.

   The project extends from the maize-rich northeast of the country to grain deficit areas along the Yangtze River and the southwest coast of China and involves extensive infrastructure developments (see table on page 27). The fundamental aim of the project is to free up the movement of some 9 million tonnes of maize and soybeans annually from the grain producing provinces in the northeast to the central and southern parts of the country and the movement of 3 million tonnes of wheat per year into the northeastern provinces. A secondary aim is to introduce modernized bulk grain storage and handling technology and to begin a program of modernization of China's grain handling infrastructure.

   The project was conceived in 1991 and gained approvals from the World Bank and the Chinese government in March 1993. Construction work began in October 1994, and the first new storages are now largely completed in three northeastern inland depots. International tenders have also been called for the supply of the first new dryers and for grain handling equipment at several depots. Progress is nevertheless slow, and it can be expected that the project will not be completed much before the turn of the century.

   UNDERDEVELOPED SYSTEMS. Despite rapid progress in many sectors, China's grain storage and handling systems are still relatively underdeveloped.

   Large quantities of grain in the northeast provinces are stored in temporary 80- to 100-tonne “mat” silos, constructed from fiber matting spirally wound to form the silo walls as grain is placed inside. The largest proportion of “permanent” storage is in the form of brick or concrete warehouses of between 2,000 and 5,000 tonnes capacity that are generally unsuited to mechanization and rarely incorporate mechanical handling equipment.

   Silos are less commonly used, with typical facilities consisting of brick silos with 300 to 1,000 tonnes of capacity, interconnected concrete bins of 800 to 1,500 tonne capacity and steel bins of 1,000 to 2,500 tonne capacity. Silos are usually fitted out with handling equipment of local manufacture, often of poor reliability and short life expectancy.

   While grain is often stored in bulk, about 90% of it is transported in bags, whether by road or by rail. Bagging and unbagging of grain employs part of the industry's vast labor force, which is currently cheap and plentiful.

   But working conditions are poor and labor costs can be expected to rise. Already, costs associated with the use of bags are considerable, and grain losses that result from their use are also believed to be substantial; control of shipping and receival weights is problematic, making real losses difficult to determine.

   Drying of maize in the northeast provinces presents some of the most unusual aspects of grain handling in China. Maize is harvested in late autumn and stored on-farm until the winter. Farmers dry the maize on the cob as best they can, but by the time of the winter freeze, moisture levels are usually still in the 25% to 30% range.

   Shelling is delayed until the grain is frozen, which, it is claimed, results in less breakage of the maize seeds.

   Only after temperatures have dropped well below freezing is the surplus grain sold to the government controlled depots, where it has to be dried, stored and shipped out. Thus, drying only commences after the grain is frozen, allowing the depots to safely store the wet grain during the winter period and to extend the drying season over four or five months.

   Drying methods include air-drying (possible in the very low humidity winter conditions) and hot air drying. Hot air dryers include cross-flow, mixed flow and concurrent flow types, almost all of which are locally designed and manufactured, though many designs are based on overseas technology. In addition, there are the indigenous and unique brick and concrete “steam dryers,” in which the grain is passed through several tall, narrow bins fitted with steam-heated tubes and high capacity fans. While expensive, this type of dryer is reputed to provide a gentle drying process creating very low levels of stress fracture in the grain.

   All dryers in northeast China use coal as their heat source; in the past, larger dryers have used steam for heat transfer, while smaller dryers used air-to-air heat transfer. However, there is now a trend toward reducing capital costs by adopting air-to-air heat transfer even for larger dryers.

   STORAGE DEVELOPMENTS. A wide range of infrastructure developments are taking place in the northeast, the most important of which are:

   1. the construction of large capacity silos of up to 10,000 tonnes;

   2. improved storage technologies such as recirculatory fumigation and aeration;

   3. construction of bulk handling systems for the receival and dispatch of grain;

   4. introduction of improved drying technology by opening the market to competition from overseas dryer manufacturers;

   5. development of higher quality and higher capacity bulk grain handling equipment together with better electrical and control systems;

   6. development of high capacity bulk train loading facilities with batch-weight delivery systems;

   7. the supply of a fleet of modern bulk rail cars for loading, transporting and unloading of grain; and

   8. new port facilities for transfer of grain from land to sea.

   One of the more interesting and visual aspects of the G.D.M.P. is the development of larger silos to reduce storage costs. Large diameter tanks, or “squat silos,” with capacities of 5,000 to 20,000 tonnes and even larger, are commonly used in North America and Australia for storing grain, but are unheard of in China.

   The low cost of this form of construction is achieved partly through the use of large storage volumes. However, compared to large “horizontal” warehouse-type storages, costs can be substantially reduced through the structural efficiency of the silo shape — cylindrical walls that carry grain loads in tension and conical or dome roofs that act as shells in carrying loads. Foundation costs can also be substantially reduced. Typically, in western countries, the cost of storages of this type may be half that of a vertical silo.

   Whether such cost reductions are possible in China is still uncertain. Costs quoted for silo and warehouse construction are substantially less than they are in the west, but in an environment where land is scarce and its costs are high, tank silos offer substantial savings in land use compared with most current forms of storage.

   Chinese engineers and grain handlers remain skeptical about the benefits of squat silo storage, mainly because this type of storage is as yet untried. Their fears are understandable, centering on concerns about the risks associated with storing such large quantities of grain in a single mass compared with what they are accustomed to.

   This is a real concern because maize for domestic consumption is dried to 14.5%. This is close to the limit for safe long-term storage, raising the risk that poor drying practices could cause grain to deteriorate rapidly during the warm summer months. Nevertheless, three of the first silos to be built under the project are squat silos; they are intended to serve as models to assess whether the technology can be applied successfully.

   The “models” are all of Chinese design and comprise features that are not common in the west. The first model is a 10,000 tonne, 40-meter diameter concrete silo with 8-meter high buttressed walls and a dome roof (see photo). Several doors have been built into the wall to allow the silo to be used as multi-purpose storage capable of storing grain in both bulk and in bags.

   Costs are claimed to be low — in the order of RMB170 (U.S.$20) per tonne compared with the cost of steel silos at around RMB250 (U.S.$30) and concrete silos at more than RMB300 (U.S.$37). The squat silo is not significantly cheaper than brick silos, but it can be expected that refinement of the design may create cost savings in the future.

   The second “model” conforms more closely to North American and Australian silos of this type. Two of these silos have been constructed, each of 38 meters in diameter and 6,800 tonnes capacity. They incorporate unbuttressed 6.8-meter high concrete walls and a steel framed, steel clad roof. Costs are claimed to be in the order of RMB240 (U.S.$29) per tonne. Once again, it can be envisaged that cost savings could be made through refinement of the design, particularly in the roof area.

   Another type of silo, of which several examples are to be built, has a capacity of around 5,000 tonnes, is 23 meters in diameter and has 18-meter high concrete walls with a steel roof. Construction of these silos was to commence in the second quarter this year, and costs were not precisely known.

   While grain temperature monitoring is commonly used in China, two other important tools in grain storage management are not yet in common use. These are aeration and the use of recirculatory fumigation techniques in properly sealed storages. Aeration may prove to be the most important because insect problems are reportedly scarce in the cold climatic conditions of northeast China.

   High capacity aeration systems are to be incorporated in all new large capacity storages being built under the project as a means of minimizing storage problems caused by moisture migration. In some cases, mostly in the warmer southern areas of the region, storages will also be sealed to allow phosphine fumigation using methods developed in Australia. All storages will be fitted with grain temperature monitoring and aeration control systems.

   Tenders have been called for the first batch of new dryers to be built for the project. Capacities range from 100 to 700 tonnes per day.

   Different types of dryers have been offered, but it is not yet known what types will be selected. Stress-cracking during drying may be an important issue in the selection because the percentage of broken maize is an important quality determinant in China.

      Some existing dryer types in China cause a high level of stress-cracking, and while this causes few problems in bagged grain, there is concern that it may become a problem in bulk handling systems where grain is less gently treated. Evidence of this potential problem is already apparent in a recently completed Australian funded depot development in Jilin province (see March 1992 of World Grain, page 17).

   BULK GRAIN DISTRIBUTION SYSTEMS. All new facilities will be provided with bulk grain receival, handling and dispatching systems. Grain from farmers will continue to be delivered in bags, but from that point on, handling and transportation will be in bulk.

   “Primary depots,” which are those that receive and store grain from farmers, will deliver grain in bulk to “intermediate depots” for dispatch by rail to port. New bulk trucks will be procured to facilitate the movement of grain from primary to intermediate depots; some depots will purchase self-tipping units, while others will install truck-tipping platforms at the receival hoppers to allow the use of non-tipping trucks. Cleaners will be provided at receival points to remove coarse and fine particles from the grain to reduce storage problems.

   Handling equipment will generally be in the range of 100 to 200 tonnes per hour to allow the use of standard equipment currently manufactured in China. Higher capacities will be needed at some of the larger depots, while primary depots will tend to have smaller capacities.

   All types of conveying equipment will be used, as there appears to be no industry-wide preference in China. But there is a predominance of air-supported belts, which are gaining popularity in the country. It remains to be seen how well these will perform in the cold winter conditions.

   A major difficulty that has to be faced is the handling of high moisture grain received from farmers. High moisture grain is delivered in a frozen state, and often combines a high proportion of fine material mixed with powdered ice; this mixture cakes on the inside of cleaners, elevators, conveyors and chutes to the extent that the equipment is rendered inoperative if it is not cleaned regularly.

   Shipping of grain from the intermediate depots onto the rail system for delivery to port involves the development of new technologies in China, replacing the current manual bag-loading methods with modern bulk loading systems. This is a critical area of development since the ability of the inland system to deliver the annual target of 9.1 million tonnes of bulk grain to port depends on it.

   One surprising advantage of bag handling is that loading of trains can be accomplished very quickly, since all rail cars in a train can be loaded simultaneously. Speedy turnaround of rail cars is important because rail utilization in China is extremely high and railway authorities often impose strict limits on the time that can be taken to load.

   Existing bulk loading methods in China emulate bag loading methods in the use of multiple bins located alongside the rail track — one for each car in the train. Because of the high capital cost of these systems, single point loading systems are being developed for the G.D.M.P. project, requiring the cars to be moved through the loading point as they are filled.

   Several types of loading systems are planned from which an industry standard may evolve. These include four-spout systems designed to feed grain simultaneously into the hatches of hopper cars and simpler single spout systems. All will incorporate batch weighing for recording the quantities of grain as it is dispatched.

   An unusual problem compared with western countries relates to local railway regulations, which do not permit main-line locomotives to be used for moving rail cars as they are loaded; the railway bureaus permit only “road-railer” units and specialized winching systems to be used. To overcome this problem, depots are having to invest in car-moving systems.

   The largest single component of the G.D.M.P. project is the construction of a new grain port near Dalian at the southern tip of Liaoning Province. The new port is to be built to handle the planned annual shipments of 9.1 million tonnes of maize and soybeans from the northeastern provinces and the importation of up to 3 million tonnes of wheat.

   This development alone is expected to cost around RMB2 billion (U.S.$244 million) and will include the construction of a new breakwater; two berths, one to handle 30,000 dwt vessels and one for 10,000 dwt vessels for shipping maize and soybeans; a berth to handle 80,000 dwt vessels for wheat imports; one 2,000 tph ship loader; two 1,000 tph shipunloaders; 300,000 tonnes of new vertical silos; a new rail link between the port to the main Harbin-Dalian rail line; associated marshalling yards and train unloading facilities; new roads and other associated infrastructure. Preliminary earthworks have already been started for the new port, which is expected to be completed by the year 2000.

   Chris Newman is director of Chris Newman & Associates Pty Ltd., a bulk grain storage and handling engineering company with offices in Australia and Beijing. Mr. Newman has been actively involved in the China grain storage and distribution project.

China's Grain Distribution and Marketing Project

   The project funded by the World Bank consists of the following components:

   • development of 59 inland depots in the northeast provinces of Liaoning, Jilin, Heilongjiang and the Autonomous Region of Inner Mongolia to facilitate loading of grain onto trains in bulk;

   • some 4 million tonnes of new silo storage in these northeast provinces;

   • about 100 hot-air grain dryers in the northeast provinces with a combined capacity of around 2.5 million tonnes per year;

   • a new dedicated grain port near Dalian in northeast China for dispatching of maize and for unloading of wheat;

   • a new berth and shiploading facility at the port of Yingkou in northeast China;1

   • major new storage and handling facilities at the Beijing Central Grain Depot;

   • shipunloading and barge loading facilities at Nantong and Jingjiang near the mouth of the Yangtze River;

   • barge unloading and transfer facilities at several ports along the Yangtze River;

   • a ship unloading facility at Fangcheng on the southern coast, together with an inland distribution network of inland depots;

   • about 1,000 road trucks for transportation of bulk grain; and

   • around 2,400 dedicated hopper rail wagons for movement of bulk grain.

   1The Yingkou port development has become uncertain and may not proceed.