1.Project Overview

APL Company gypsum powder plant with capacity of 80,000 tons per year is located in CASABLANCA area, Morocco.

APL Company owns the powder plant, gypsum board plant and panel plant. ZK Corp is responsible for the powder plant.

  2. Production Requirement

 3. Raw Material Condition

4. Construction Site Condition

 4. Labor Plan

According to the production process needing, the combination of fixed position workers and inspection workers is adopted. The production line operates in three shifts and 8 working hours per shift.

5. Process Flow Description

5.1Brief introduction of gypsum flue gas tube calcining kiln

  Flue gas tube calcining kiln is a widely used rotary calcining equipment.The indirect heat exchange is carried out by heat exchange pipe set in the rotary kiln as the main heat exchange surface. In addition to the advantages of external rotary kiln itself, it also has the advantages of tubular calcining equipment, which is a medium temperature calcining equipment between high temperature rapid heat exchange equipment and low temperature heat exchange equipment. The heat transfer of equipment has changed from simple flue gas circulation to complex multi-return heat transfer system.

5.2 Calcining kiln and its working principle

  Flue gas tube calciner is an indirect heat calcining equipment. Its main heat exchange part is the pipes inside of a kiln body, heat transfer surface is the pipe surface, heat from the hot air in the piping, heat transfer heat to the pipe surface.  Materials and heat transfer and the outer wall of pipeline with the pipeline surface contact to the materials and kiln body radiation heat is the main form of pipe calciner flue gas heat. Therefore, the hot air temperature and the form and structure of the pipe inside the kiln and the main parameters of the calcining kiln when effectively contacting with materials.

  In the rotating process of flue gas pipe calcining kiln, the pipe rotates with the kiln body, and the materials in the kiln body are mainly accumulated at the bottom of the kiln body and constantly billowing. The pipe continuously pass through the material layer and carries part of the materials along with the pipe. Therefore, the maximum degree of pipeline contact with the material and a longer time with the pipeline movement, will greatly improve the heat transfer efficiency, the higher the kiln body revolution, the higher the frequency of pipeline "through" the material, can effectively improve the heat transfer. However, a higher number of revolutions will lead to the material moving speed too fast to reach the calcining time. Therefore, each different kiln of this kind of calcining kiln must find the best value between the calcining time and the number of revolutions. At the same time, material layer thickness and material filling rate is another major factor to ensure output and heat transfer efficiency. Appropriate material layer thickness can better improve the contact surface between pipeline and material and improve heat transfer efficiency.

  At present, our company adopts the latest three-return flue gas pipe calcining kiln, which has high heat utilization efficiency and stable product quality. Under the premise of ensuring product quality and performance, the heat utilization efficiency of the equipment and the lowest gas consumption are the most direct way to control the production line cost and improve the benefit.

5.3 Description of production line technical parameters

1) The production scale of this production line is designed to produce 12 tons of building gypsum powder, and a set of flue gas pipe calcining kiln is used; The one-step process of flue gas tube calcining kiln is adopted. The drying and calcining of desulfurized gypsum with water are completed in one equipment, and the drying and calcining dehydration of two-water gypsum are completed in sequence after entering the calcining kiln. The equipment has strong adaptability to the moisture of raw materials, and the particle size of a small amount of raw materials has no influence on the calcining process. At the same time, material drying and calcination in the same equipment is completed continuously, reduce heat loss, simple production process, less investment, product quality is better guaranteed;

2) Environmental protection of the production line is designed according to the environmental protection requirements of a class of domestic regions, considering dust, noise, tail gas;

Design according to the requirement of dust emission concentration less than 20 mg/m3;

Noise is mainly caused by induced draft fan of calcining kiln dust collector. Frequency conversion motor and muffling measures can be adopted to reduce noise effectively.

The water discharged from the production line during operation is steam condensed water, no pollution, can be reused;

3)A central control room is set up on the production line to realize DCS centralized control, and control signal sources are set up on all the equipment and control points from feeding to packaging;

4) The production line is mainly based on silo storage; The production line is equipped with 2 grinding head bins to adjust the abnormal production of clinker and stabilize the mill feeding; 4 finished product warehouses are set for product storage, and the general storage period of finished products is set according to 4 days of storage; Mortar line gypsum powder conveying and supply and bulk equipment of ton bag packing machine are respectively set at the bottom of 4 finished products warehouses (2 warehouses provide powder demand for mortar production line, 1 warehouse bottom is equipped with ton bag packing, and 1 warehouse bottom is equipped with bulk system).