I. Overview
ZCGT drum slag cooler is designed and developed to meet the requirements of circulating fluidized bed boiler developing to large capacity. It is composed of a hundred sheet heat transfer drum, a slag inlet device, a slag outlet device, a rotating mechanism, a cooling water system and an electronic control device, which is used for the hot slag cooling of circulating fluidized bed boiler.
Two, structural characteristicsThe reason why the roller slag cooler is more and more common to replace the large size CFB boiler original "fluidized slag cooler", Z the company patent number :ZL201120087499.6 has the following characteristics:
1. Excellent output regulation performance
Hot ash enters the end of the drum through the slag inlet tube with a diameter of no less than 200mm, and accumulates around the slag inlet tube to a certain height. When the gravity generated by the slag flow in the tube is balanced with the gravity of the slag flow in the tube, the slag flow in the tube will be blocked. When the roller rotates and pushes the ash to move to the drum slag end, the height of the slag pile around the slag inlet pipe end drops and breaks the gravity balance of the ash inside and outside the pipe, and the slag flow inside the pipe continues. In this way, the roller rotates, and the hot slag flows in; The roller stops, the hot slag flow stops; Fast turn fast forward, slow turn slow forward. The speed of slag inlet reflects the output of slag cooler, that is, the output is a function of the roller speed, and is linear. The roller speed is controlled by the frequency converter of the inverter motor driving the roller. The press signal reflecting the height of the CFB boiler bed material is connected to the frequency converter and becomes the motor speed control signal, thus realizing the automatic tracking of the output of the slag cooling machine and the adjustment of the boiler slag quantity, without the need to stare at the instrument and manually adjust.
2. Wide range of ash particle size adaptation, reliable operation guarantee
There is no need for any flow control in the whole slag discharge pipe from the boiler slag discharge port to the drum slag inlet end, so there is no possibility of coking blocking the slag discharge pipe due to the air control air combustion of the original fluidized slag cooler, and there is no possibility of coking of ash slag in the slag cooler. And, no matter how much ash particle size and slag amount, will not affect the normal operation of the slag cooler. There has never been an accident of stopping the furnace due to the malfunction of the spirit type slag cooler.
3. Good slag cooling effect
Due to the heat exchange area and heat exchange surface of the slag cooler doubled and improved, the cooling slag effect is excellent, adapt to the large size of the unit slag quantity of cold slag requirements, the use of wind, water at the same time and scattered materials for heat exchange, water cooling, cold slag effect is good, maintain the slag activity, conducive to the comprehensive utilization of ash and slag and environmental protection. The amount of cooling water is small, and there is no special requirement for water quality. Power plant circulating cooling water or general industrial water can be used. The use of wind (natural wind), water double cooling medium, improve the heat transfer effect, reduce the slag temperature, is conducive to the mechanical transportation of ash slag. Especially if the forced ventilation system is used, the cooling effect will be greatly improved. The cold slag outlet temperature is low, which ensures the working conditions and safe operation of the subsequent conveying equipment. From the actual operation of the power plant, the slag temperature is low and the expected goal is achieved.
4. Unique structure, reliable and long-lasting anti-leakage slag device
To prevent hot slag from leaking out of the connection between the rotating drum and the static slag inlet device, at present, there is no any kind of slag cooling function like the spirit type roller slag cooling machine to solve the problem thoroughly, so that the droplet does not leak, and its component life is long, easy to replace. It can be said that the structure is unique and ingenious. At the same time, the negative pressure suction device at both ends of the drum effectively prevents the spillover of fine ash and ensures the cleanliness of the environment.
5. Adjustable height of support wheel
After running for a long time, the height of the drum drops beyond the limit, which will affect the sealing gap of the anti-leakage slag device. Through the roller height adjustment to maintain the normal height of the roller at the same time can be convenient maintenance of the support wheel, and this is equipped with the roller height indication and the roller falling beyond the limit alarm, is another patent structure of the spirit type roller slag cooler.
6. All transmission wear parts can be replaced
The transmission wear parts of the spirit type roller slag cooler, including the support ring and the big tooth ring, can be replaced. Small parts are easy to replace, but the support ring, the big gear ring are wear large parts, wear failure can be replaced is necessary for the long life of the whole machine, this is the unique structure of the machine.
7. Highly praised spirit rotary water joint
Rotary water joint is one of the important parts of roller slag cooler. In the early 1990s, the spiral slag chiller began to use the American Johnson technology of cooling water joint, and then used in the roller slag chiller, but so far has not been satisfactory, so domestic manufacturers began to develop suitable for slag chiller rotary water joint. At present, the operation effect of the spirit rotary water joint is reliable, long - lasting, less and simple maintenance, so it becomes the best choice of power plant.
8. Reliable two-stage overpressure safety protection measures
So far, there have been at least three explosion accidents of roller slag cooler in China. The reason is that when the roller slag cooler is temporarily shut down and restarted, the completely closed inlet and outlet valve of cooling water forgets to open, resulting in the overpressure of the cooling water in the roller water chamber and the tear of the shell weld.
The roller slag cooling machine is equipped with two levels of explosion-proof safety protection: the first level is when the roller water chamber pressure loss (not open the water supply valve) or overpressure (water chamber vaporization), electrical (electric contact pressure gauge and armored platinum resistance thermometer) automatic stop (hot slag shutdown will avoid continued vaporization pressure boost) and alarm; When the first stage failure and water chamber overpressure, the safety valve action and pressure relief as a secondary protection.
9. The energy-saving effect is very considerable
The 465t/h boiler analysis report of a power plant in Shandong is taken as an example. Two drum slag coolers with each running power of 7.5kW are replaced by two fluidic slag coolers. The fluidic fan with 350kW(rated power of 400kW) and two scraper conveyors with a total running power of 8kW are removed. The operation power of the secondary fan is increased by about 106kW, so the operation power reduction of the auxiliary boiler is as follows: 350+8-15-106=237kW, calculated according to the unit's annual operation of 7000 hours, a year can save 1.659 million KWH of electricity, the economic benefit is very objective, which is its direct benefit, because the replacement of drum slag cooler improves the reliability of the unit's operation and reduces the unplanned outage, thus bringing more comprehensive benefits. The roller slag cooling machine is equipped with two levels of explosion-proof safety protection: the first level is when the roller water chamber pressure loss (not open the water supply valve) or overpressure (water chamber vaporization), electrical (electric contact pressure gauge and armored platinum resistance thermometer) automatic stop (hot slag shutdown will avoid continued vaporization pressure boost) and alarm; When the first stage failure and water chamber overpressure, the safety valve action and pressure relief as a secondary protection.

Three, the main technical parametersCooling medium to water, the most appropriate softening water. The air cooling effect is small (generally no more than 5%), but its outlet needs to be connected to the air intake system (usually connected to the inlet of the electrostatic precipitator), otherwise the cold slag will have dust escape and pollute the environment.
Cooling water W (t/h), when excluding the air cooling effect can be calculated according to the following formula:
W=0.24×Pz× (Tz1-Tz2) ÷ (Ts2-Ts1)
Where, Pz: slag amount (t/h)
Tz1-Tz2: Temperature difference between inlet and outlet slag (℃)
Ts2-Ts1: Temperature difference between inlet and outlet water (℃)
The cooling water of the roller slag cooler of large-size CFB unit is generally taken from the outlet of the condenser condensate pump and returned to the final low feed outlet. According to the condensate pump outlet water temperature 45℃, the cooling water outlet temperature of the slag cooling machine 95℃, slag inlet temperature 950℃, slag discharge temperature 100℃ calculation, each ton of slag needs 4.08 tons of cooling water, saving a lot of water resources, at the same time, the heat energy released by the furnace bottom slag can be fully recycled.

5. Installation instructionsAccording to the location of the driving motor, the slag cooling machine has left type and right type: facing the outlet of the slag cooling machine, the motor on the left is left type, and the motor on the right is right type.
The slag chiller is placed flat on the ground with a bearing capacity of no less than 600kgf/m2, without anchor bolts, only embedded iron is installed on the ground at the four corners of the base of the slag chiller. After the slag chiller is in place, electric welding is performed on the embedded iron to prevent horizontal movement.
When installation above ground level is required, two longitudinal or four transverse C30 soil strip foundations can be cast above ground level.
When the two types of slag chiller are arranged side by side, in order to facilitate maintenance and debugging, the driving motor should be made on the outside, that is, from the direction of the slag outlet: the left type slag chiller is placed on the left, and the right type slag chiller is placed on the right.