Article published in

World Grain Magazine

Apr 2000 Issue

 

REVISITING CHINA'S GRAIN STORAGE PROJECT

The New Dalian Grain Terminal nears completion

Introduction

The giant new Dalian Grain Import and Export Terminal being constructed under the auspices of the Dalian Beiliang Company on the outskirts of Dalian in the North East of China is now nearing completion and is expected to begin handling grain in mid-2000.

The terminal consists of two separate storage areas built under separate projects. The "Phase 1" component consists of 150 bins of 3000 tonne capacity (constructed as part of the World Bank Grain Distribution and Marketing Project). The "Phase 2" component consists of 20 enormous 30,000 tonne free-standing silos (constructed as part of the domestically funded China Grain Storage Project).

The two storage areas are linked by overhead conveying systems, but are expected to be operated independently - one providing transit storage for imported and exported grain, and the other providing longer term storage.

The World Bank Grain Distribution and Marketing Project (described more fully in WGM April 1996) is a $1 billion project aimed at providing the infrastructure to move surplus corn in bulk out from the North Eastern provinces of China to "deficit" urban areas in central and southern China, and for facilitating the importation of wheat back into the North Eastern provinces. The new Dalian terminal plays a pivotal role in this plan, being the gateway for the outward movement of at least 6 million tonnes of corn, and the importation of up to 3 million tonnes of wheat per year.

Features of the Phase 1 Terminal

The Phase 1 section of the terminal has been designed to handle over 9 million tonnes of wheat and corn into and out of the country. The silos are all self-emptying with steel hopper bases, and are built in the form of two blocks each with four rows of interconnected bins. A central "working area" divides the two blocks and incorporates four screeners and eight working bins for cleaning and segregating grain.

There is only one elevator in the Phase 1 section of the terminal - a small (200 tph) unit for handling truck receivals. Otherwise, all grain will be elevated on long inclined conveyors. These include:

All conveyors are conventional troughed idler belts with a 40o troughing angle. Over each block of silos is a massive gallery structure housing travelling trippers for transferring grain from conveyors to the silos.

Because this part of the terminal is to be used for short-term transit-storage (with average turn-around of about 10 days), no aeration has been provided in the silos. Fumigation has however been provided in 27 of the main bins and 4 of the working bins as described in more detail below.

Features of the Phase 2 Terminal

The Phase 2 section of the terminal is designed as a longer-term storage, and consists of 20 independent 30,000 tonne capacity silos - believed to be amongst the largest in the world. Each silo has a concrete wall 32 metre diameter x 45 high, and is capped with a conical steel and concrete roof structure. The silos all have flat floors with fitted with eight radial aeration ducts each with its own aeration fan.

Conveying capacity into and out of the silos is 1000 tonnes per hour, and all conveyors are of the air-supported belt type. Because of space limitations, two 1000 tph elevators will be used to lift grain from the undersilo conveyors to the elevated conveyors that will return the grain to the Phase-1 transit storage block.

Being for long-term storage, all silos will be fitted for recirculatory fumigation as well as aeration.

Being a Chinese funded project, almost all the of the equipment is being sourced from Chinese suppliers. Only the two bucket elevators, fumigation and temperature monitoring systems are imported.

Dalian Fumigation Systems

Of the many advanced features of the Dalian terminal, of particular interest are the fumigation systems that are being fitted to both Phase 1 and Phase 2 storages. Supplier of the fumigation systems is Grain Tech Systems Pty Ltd (GTS) of Australia, which won contracts for both projects based the supply the latest SIROCIRC® grain fumigation technology from Australia. GTS introduced the technology into China in 1997 with a demonstration installation near Beijing (as described in World Grain Magazine article in April 1998). For the two Dalian projects, GTS has adopted a more sophisticated version of the technology than was used in that early installation.

Features of SIROCIRC®

SIROCIRC® is an Australian patented technology which uses gaseous phosphine dispensed from cylinders instead of the traditional tablet formulations based on aluminium or magnesium phosphate. This phosphine formulation offers several very significant advantages including:

SIROCIRC® is a development of the earlier SIROFLO® system developed by CSIRO in Australia in the 1980s. The principal function of both technologies is to control the release of gaseous phosphine into a stream of air that is blown continuously (upwards) through a grain mass during the entire fumigation period, such that the concentration of phosphine in the air-stream is maintained at a constant pre-set level.

With SIROFLO®, the phosphine passes upwards through the grain mass, and disperses continuously to the atmosphere through "leaks" in the storage. With SIROCIRC®, phosphine is collected from the top of the storage and recycled back through the grain mass, thereby reducing the consumption of the fumigant. An electronic controller monitors and adjusts the PH3 concentration, and terminates the fumigation at the end of a preset fumigation period. SIROCIRC® requires a higher level of seal than SIROFLO® to justify the additional cost of recirculation ducting and control equipment.

One of the features of both SIROFLO® and SIROCIRC® is that several silos can be fumigated at the same time from a single fan and fumigant dispenser. The systems are designed to ensure that the correct airflow and fumigant concentration is delivered to all silos regardless of their contents or state of filling.

Gaseous Phosphine Formulation

Until recently, the gaseous phosphine fumigation used with SIROFLO®; and SIROCIRC®; has been a mixture of phosphine and carbon dioxide marketed under the name ECO2FUME® by CYTEC Industries Inc of the USA, one of the world's leading manufacturer's of phosphine. CYTEC also manufactures a pure phosphine formulation under the name VAPORPH3OS® which can also be used for grain fumigation purposes. Both formulations are currently registered for use on foodstuffs in Australia, New Zealand, Cyprus, South Africa and Egypt, but registration is expected in the USA, Germany, China, Indonesia, Malaysia, Singapore, Thailand, and Vietnam in the near future.

New Features of the Dalian Beiliang Fumigation Systems

The Dalian Beiliang SIROCIRC® systems supplied by GTS incorporate two recent innovations which are expected to add to the flexibility and cost-benefits of the technology:

On-site mixing is carried out using mixing system developed by Gas-Apps Pty Ltd of Australia. Liquid CO2 delivered by bulk road-tanker is stored at low temperature in a 5 tonne cryogenic tank. The mixer mixes the CO2 from the tank with VAPORPH3OS® gas supplied in G-sized cylinders. A small PLC operates the opening and closing of valves for controlling the release of the two gases for passage through the mixer, making the mixing process a safe and automated operation.

The advantage of on-site mixing is that it saves cost by avoiding the transport, storage and handling of pre-mixed gas cylinders, one 13kg cylinder of VAPORPH3OS® being equivalent to 21 x 31kg cylinders of ECO2FUME®.

The "High-Flow" option allows faster fumigations of any silo by increasing the airflow through it, and delivering a high concentration of fumigant into it. This is expected to allow the time for a fumigation to be significantly reduced if the need arises to load grain out in a hurry.
Once CYTEC's current applications for registration of ECO2FUME® and VAPORPH3OS® have been granted, it can be expected that grain handlers in the USA and other countries will be able to benefit from the advantages that SIROFLO® and SIROCIRC® offer. It is possible that these new systems being installed at Dalian Beiliang might become commonplace in the future, and may even become the industry-standard method of grain fumigation in the 21st century.