JPS6291201A - Method of controlling evaporation load of steam dryer - Google Patents

Abstract

PURPOSE:To keep const. the amount of water at the outlet of a dryer, by controlling pressure control valve at the inlet side of steam depending on the amount of water controlled by a control valve for a drain water level at the outlet side of drain. CONSTITUTION:Steam as a heat source for a dryer is supplied from a boiler 1 through a pressure control valve 2 into a dryer 3. Drain water condensed in the dryer 3 is discharged therefrom and stored in drain pot 4. The liq. level in the drain pot 4 is always kept const. by a drain level control valve 5 and becomes a control element for the pressure control valve 2 together with a drain flow meter 6. In this way, temp. of the heat transfer surface of the dryer is controlled, and the evaporation load of the dryer is thus controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a technology for adjusting the moisture at the dryer outlet by controlling the evaporation load when moisture in sludge, etc. is indirectly heated and dried in a steam dryer. used in the field.

2. Description of the Related Art In conventional indirect heating type steam dryers, drain condensed within the dryer is discharged by providing a drain trap or the like at the outlet of the dryer steam line. In this method, if the amount of steam supplied is the same and the heat transfer area is constant, the amount of evaporation will be constant, and the amount of water at the outlet (sludge water content) cannot be controlled.

The conventional method of evaporation load control as described above has been attempted by reducing the amount of sludge retained in the dryer, but there are problems with responsiveness, operability, etc., and it has not yet been put to practical use.

A method of controlling the inlet steam pressure has also been considered, but if the steam pressure at the supply source does not change, the steam will be heated to N and the amount of heat supplied to the dryer will not change. Controlling the steam flow rate is also considered, but since the evaporation load changes depending on the amount of drain water in the dryer, controlling the steam flow rate is also considered difficult.

Problems to be Solved by the Invention The present invention is to enable evaporation load control, which has been considered extremely difficult in the past, as described above, and to make it possible to adjust the moisture content of the dried material at the outlet.

Means for Solving the Problems The present invention takes the following measures in order to solve the above-mentioned problems. That is, a pressure regulating valve is provided on the steam inlet side of the dryer, a drain bot is provided on the drain outlet side, and a drain water level regulating valve is further provided to control the liquid level of the drain bot. Evaporation load control is performed by controlling the pressure regulating valve.

Effect: According to the means described above, the temperature of the heat transfer surface of the dryer is controlled, the amount of heat supplied is also controlled, and the evaporation load of the dryer is controlled.

Embodiment Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Steam, which is the heating source for the dryer, flows from the boiler 1 to the pressure regulating valve 2.
is supplied to the dryer 3 via. Drain water condensed in the dryer 3 is discharged from the dryer 3 and stored in the drain bot 4.

The liquid level of the drain bot 4 is always controlled to be constant by the drain water level control valve 5, which together with the drain flow meter 6 serves as a control element for the pressure control valve 20.

Effects of the Invention Being able to control the evaporation load of the dryer means that, for example, in the drying-incineration process, it becomes possible to control the furnace temperature of the incinerator. It is possible that the moisture content of the dried product fluctuates before it enters the dryer, but by controlling the evaporation load, the moisture content at the outlet can be kept constant, and the moisture content of the dried product can be made uniform. equipment, such as incineration equipment, can be operated stably. As described above, the present invention not only adds new operating elements to the dryer, but also enables effective use in low-volume equipment.

[Brief explanation of drawings]

The drawing is a system diagram of one embodiment of the present invention. 1. Boiler, 2. Pressure control valve, 3. Dryer, 4.
・Drainbot, 5. Drain water level control valve, 6. Drain flow meter. Sub-agent Tadashi Kimura Kyo1 ゝ'd (and 7 others)

Claims (1)

[Claims] In an indirect heating type steam dryer, a pressure regulating valve is provided on the steam inlet side of the dryer, a drain pot is provided on the drain outlet side, and a drain water level regulating valve is further provided to control the liquid level in the drain pot. An evaporative load control method for a steam dryer, in which the evaporative load is controlled by controlling the pressure regulating valve according to the amount of water controlled by the regulating valve.