CN111504516A

CN111504516A - Method for measuring waste heat of recovered waste gas in thermal processing process of wood or/and wood veneer

Info

Publication number: CN111504516A
Application number: CN202010342050.3A
Authority: CN
Inventors: 何正斌; 伊松林; 王振宇; 王铭婕; 钱京; 曲丽洁; 母军
Original assignee: Beijing Forestry University
Current assignee: Beijing Forestry University
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2020-08-07
Anticipated expiration: 2040-04-27
Also published as: CN111504516B

Abstract

The invention discloses a method for measuring the waste heat of waste gas recovered in the thermal processing process of wood or/and wood veneers, which comprises the steps of measuring the number of waste heat recovery units in a waste gas waste heat recovery and measuring device; measuring the temperature of the phase change energy storage material in each waste heat recovery unit in the exhaust gas discharge process; measuring the heat recovered by each waste heat recovery unit; then adding the heat recovered by each waste heat recovery unit; and finally, subtracting the energy stored by the waste heat recovery unit before the wood thermal processing treatment to obtain the recovered waste heat. The method has the advantages of accurate measurement of the recovery amount of the waste heat of the waste gas, simple measurement method, contribution to accurate secondary utilization of the recovered heat, contribution to accurately controlling the opening and closing of a heater in the hot processing process when the stored heat is circularly used for drying the wood, saving more energy, achieving the accurate control of the wood drying, improving the quality of the hot-processed wood and reducing the environmental pollution.

Description

Method for measuring waste heat of recovered waste gas in thermal processing process of wood or/and wood veneer

Technical Field

The invention relates to a device and a method for recovering waste heat, in particular to a device and a method for recovering waste heat in a wood heat processing process, and belongs to the field of energy-saving and green heat processing of wood.

Background

The thermal processing processes such as drying, heat treatment and the like are necessary links in the processing processes of wood and wood veneers and food, fruits and vegetables, can reduce the defects of cracking, deformation and the like of wooden products such as furniture and the like in the using process, and can prevent the problems of rotting and the like of the food, the fruits and the vegetables in the storage process. The energy consumption required by wood drying is 40% -70% of the total energy consumption of wood processing at present, in the wood drying process, when the temperature of wet air rises after passing through a heater, the wet air flows through a wood pile, the heat is transferred to wood, then moisture evaporated from the wood is taken away, when the relative humidity in a kiln exceeds the humidity specified by a drying standard, the exhaust is needed, the temperature of the wet air exhausted from an exhaust port is high, the moisture content is high, and the part of heat accounts for 30% -40% of the total energy; if can retrieve this part heat, then the fresh air in the heating kiln, on the one hand can the required energy consumption of greatly reduced wood drying, reduces thermal pollution simultaneously, can reduce the pollution of wood drying industry to the environment, so, retrieve to the abandonment waste heat and recycle and be crucial to realizing the sustainable green development in the wood hot working process.

In order to recover waste preheating, the utility model patent 201820828170.2 provides an experimental device for researching the condensation mechanism of waste heat recovery of a tail gas fluorescent tube in the wood industry, which comprises a waste heat recovery box body, wherein a cooling coil is arranged in the waste heat recovery box body, one side of the waste heat recovery box body is provided with a tail gas air inlet and a hot water outlet, the other side of the waste heat recovery box body is provided with a tail gas air outlet and a cold water inlet, the tail gas air inlet is connected with a tail gas air inlet pipe, the end part of the tail gas air inlet pipe is provided with a tail gas circulating fan, and the tail gas; the tail gas outlet is connected with a tail gas discharge pipe, and a tail gas outlet pipe humiture instrument is arranged on the tail gas discharge pipe; the cold water inlet is respectively connected with the cooling coil and the cold water inlet pipe; the hot water outlet is respectively connected with the cooling coil and the hot water outlet pipe. The utility model discloses can be used for the heat exchanger mechanism research that condenses of fluorescent tube heat exchanger, the characteristic that condenses of analysis tail gas at the heat transfer in-process. The invention patent 201811075276.0 discloses a wood drying kiln, which comprises an air source heat pump unit, a waste heat recovery and dehumidification device, a drying kiln body and an intelligent drying controller, wherein one side of the drying kiln body is fixedly connected with a hanging gate, an interlayer is arranged in the drying kiln body, the upper end of the interlayer is fixedly connected with a circulating fan, one side of the circulating fan is provided with a condenser, and the other side of the circulating fan is provided with an electric heater. The invention also discloses a control method of the wood drying kiln, which comprises the following steps: preparation and B: discharging and C: starting and D: temperature and humidity measurement, E: low-temperature adjustment, F: high humidity adjustment, G: low humidity conditioning, H: alarming and I: and (5) finishing the processing. The invention achieves the effects of energy saving, environmental protection, high efficiency and no pollutant discharge by adopting the air source heat pump unit, the condenser is directly arranged on the circulating air duct in the drying kiln body, the refrigerant is directly conveyed into the drying kiln body through the copper pipe for condensation, the heat exchange temperature difference is large, and the heat exchange efficiency is high. The utility model 201820049051.7 discloses a numerical control wood drying unit with waste heat recovery, including wood drying machine group, wood drying machine group includes the wood drying machine case, and the fixed intercommunication in top of wood drying machine case has the heat energy to excrete the pipe, and the quantity of heat energy excretes the pipe is two, and the top of two heat energy excrete the pipe is linked together through connecting the converting pipe. The utility model discloses carry out effectual storage to heat energy, the convenience is carried out reuse to its inside heat energy, flow back unnecessary heat energy to wood drying machine incasement, reduce the power consumption of wood drying machine case, the energy has been practiced thrift, when the heat energy in the waste heat energy bin is too much, accessible heat energy resource discharge pipe discharges unnecessary heat energy, conveniently carry out the utilization of surplus heat energy, waste heat recovery's advantage has been reached, the current wood drying unit of effectual solution can not carry out effective abundant utilization to heat energy in carrying out the wood drying process, thereby cause the problem that heat energy loss can not reach energy-concerving and environment-protective. The utility model 201721681320.3 discloses a self-loopa tunnel type carbonization kiln relates to the wood working field, include: the carbonization kiln comprises a carbonization kiln body and a circulating system connected with the carbonization kiln body, wherein the carbonization kiln body comprises a preheating and drying area, a pyrolysis area, an oxidation area, a reduction area and a cooling area, and the circulating system comprises a waste heat recovery system, a fuel gas reusing system and a tail gas treatment system. By adopting the technical scheme, the waste heat recovery system and the gas reuse system are added on the basis of the carbonization kiln, the conversion rate of carbon is improved and can reach 35%, and meanwhile, due to the arrangement of the tail gas treatment system, the tail gas emission can reach the natural gas standard, clean and environment-friendly production is realized, and meanwhile, continuous, efficient and automatic production for carbon preparation is also realized. Utility model 201720793691.4 discloses a high temperature timber waste heat recovery device, include: a clamping plate: two straight arms and arc-shaped connecting parts which are arranged in parallel; two ends of the arc-shaped connecting part are respectively connected with the two straight arms, and the clamping plate is U-shaped; graphene bags: the graphene bag is fixedly arranged on the inner side surface of the clamping plate; the heat absorption liquid is filled in the graphene bag; a clamp: comprises a first clamping piece, a second clamping piece, a screw and a limiting block; the first clamping piece and the second clamping piece are parallel to each other, and a screw rod is arranged on the upper surface of the first clamping piece; the second clamping piece is equipped with the through-hole, and the free end of screw rod runs through the through-hole from bottom to top, and the stopper be equipped with screw rod complex screw, the stopper is connected in the free end of screw rod, first clamping piece and second clamping piece centre gripping respectively in the junction of two straight arms and arc connecting portion, the utility model discloses the waste heat recovery device centre gripping is stable, and heat dissipation heat conduction efficiency is high, effectively prevents timber fracture.

Although the existing inventions can recover the waste heat to a certain degree, the existing inventions (1) can not realize the effective storage of the waste heat, realize the utilization of different time and space and have great limitation; (2) the installation process is complex, and the investment is large; (3) the amount of stored heat cannot be obtained on line in real time, and accurate heat recovery cannot be realized.

Disclosure of Invention

The invention aims to provide a method for measuring waste gas waste heat recovered in the wood or/and wood veneer thermal processing process aiming at the technical problems that the waste gas discharge amount is large in the wood or wood veneer thermal processing process, the heat loss is serious due to the waste gas taking away, the environmental pollution and the energy waste are caused, and the discharged heat cannot be accurately calculated and recovered, the method aims at efficiently utilizing the waste gas waste heat, the waste gas waste heat recovery amount can be accurately measured by adopting the method, the waste heat can be measured and stored in real time in the thermal processing process, the stored waste heat is utilized subsequently, the heating time or power of a heater in the thermal processing process is reduced, so that theoretical guidance can be provided for the allocation of an internal heater in the drying kiln design process, the excessive allocation of the heater in the kiln is avoided, and the energy is wasted, meanwhile, the opening and closing of the heater in the kiln can be accurately controlled by predicting the quantity of the recovered heat, so that more energy is saved, and the accurate control of wood drying is achieved.

In order to achieve the purpose of the invention, the invention provides a method for measuring the waste heat of the recovered waste gas in the thermal processing process of wood or/and wood veneers, which comprises the following steps: firstly, measuring the number of waste heat recovery units contained in a waste gas waste heat device during the wood hot processing; then measuring the temperature of the phase change energy storage material in each waste heat recovery unit in the exhaust gas discharge process; then measuring the heat recovered by each waste heat recovery unit; then adding the heat recovered by each waste heat recovery unit; and finally, subtracting the energy stored by all the waste heat recovery units before the wood thermal processing treatment to obtain the recovered waste gas waste heat.

The device for recovering and measuring the waste heat of the waste gas in the wood thermal processing process comprises at least 1 waste heat recovery unit and a temperature sensor arranged in the waste heat recovery unit.

Particularly, the waste heat recovery unit comprises at least 1 waste heat recovery pipe which is internally packaged with a phase change energy storage material and a recovery pipe frame for placing the waste heat recovery pipe. The waste heat recovery unit comprises a plurality of waste heat recovery pipes and a recovery pipe frame, wherein the waste heat recovery pipes are internally packaged with phase change energy storage materials, and the recovery pipe frame is used for placing the waste heat recovery pipes.

Particularly, the temperature of the phase change energy storage material in each waste heat recovery unit is measured in real time by adopting a temperature sensor which is arranged in the waste heat recovery unit in a device for recovering and measuring waste heat of waste gas in the wood heat processing process.

Particularly, the temperature sensor is fixedly installed in the waste heat recovery pipe, the (n +1) branches are sequentially arranged from inside to outside along the radius of the cross section of the waste heat recovery pipe from the circle center to the inner wall of the pipe, the radius of the cross section of the waste heat recovery pipe is divided into n parts, and the temperatures of the phase change energy storage materials packaged in the waste heat recovery pipe at different positions along the radius direction of the cross section of the waste heat recovery pipe are respectively measured.

The invention also provides a method for measuring the waste heat of the recovered waste gas in the thermal processing process of the wood or/and the wood veneer, which comprises the following steps:

1) determining the number A of waste gas waste heat recovery units and waste heat recovery units in the device in the thermal processing process of the wood or/and the wood veneer;

2) arranging the waste heat recovery pipes contained in each waste heat recovery unit on a recovery pipe frame in a forward or staggered manner, and measuring the number h of rows and the number l of columns of the recovery pipes arranged on the recovery pipe frame of each waste heat recovery unit, the number of the recovery pipes in each column and the pipe inner diameter R of the recovery pipes;

3) selecting W recovery pipes in each row of recovery pipes of the recovery pipe frame of each waste heat recovery unit as temperature monitoring pipes, and arranging a temperature sensor in each row of recovery pipes; installing (n +1) temperature sensors respectively marked as G0, G1, G2, …, Gi, …, Gn-1 and Gn in each selected temperature monitoring pipe, measuring the corresponding radiuses of the positions of the temperature sensors in the waste heat recovery pipe respectively marked as R₀，R₁，R₂…, Ri, …, Rn-1, Rn; wherein R is₀0; rn ═ R; wherein W is more than or equal to 1;

4) the temperature of the phase change energy storage material in each temperature monitoring pipe at different positions along the radius of the waste heat recovery pipe is measured in real time in the wood hot working process and recorded as T_R0，T_R1，T_R2，…，T_Ri，…，T_Rn-1，T_RnAnd meterCalculating the average temperature between two adjacent temperature sensors

5) Determining the heat quantity q absorbed by the jth row of recovery pipes in each recovery unit according to the formula (1)_Lj，

In equation (1): q. q.s_LjIs L th in the recovery unit_jTotal heat absorbed by the row of recovery tubes, J; h_iJ/g of heat stored by the phase change energy storage material with unit mass in the phase change energy storage material contained in the part between the cylinders formed by taking the positions of the ith and i-1 sensors as the radius in the temperature monitoring pipe, n is the total number of the temperature sensors arranged in the temperature monitoring pipe minus 1, W is L_jThe number of temperature monitoring tubes in the row of recovery tubes, h is L_jThe number of recovery tubes in the row; r_i、R_i-1The radius and mm of the ith temperature sensor and the i-1 temperature sensor in the temperature monitoring pipe are respectively corresponding to the temperature monitoring pipe; m is the total mass g of the phase change energy storage material encapsulated in the recovery pipe; r is the inner diameter of the waste heat recovery pipe, and is mm;

6) measuring the heat quantity Qz stored in each waste heat recovery unit according to the formula (3);

wherein Qz is the heat stored by a single waste heat recovery unit in the waste gas waste heat recovery device, J; i is the row number of the recovery pipes in the recovery unit; j is the jth row of waste heat recovery tubes in the waste heat recovery unit; q. q.s_LjIs L th in the recovery unit_jTotal heat absorbed by the train waste heat energy recovery pipes, J;

7) determining the total heat Q stored by all waste gas waste heat recovery units in the waste gas waste heat recovery and determination device in the wood thermal processing process according to the formula (4)_{General assembly}；

Wherein

Q_{General assembly}Recovering and measuring the total heat stored by all waste gas waste heat recovery units in the waste gas waste heat device in the wood hot processing process, J; a is the number of waste gas waste heat recovery and waste heat recovery units in the measuring device; z is one of the A waste heat recovery units;

8) determining the total heat Q of the exhaust gas residual heat absorbed by the residual heat recovery and determination device according to the formula (5)_{Store up}：

Q_{Store up}＝Q_{General assembly}-Q₀(5)

Wherein Q is_{Store up}The total heat recovered by the waste gas waste heat recovery and determination device in the wood hot working process is J; q_{General assembly}The total heat stored by the waste gas waste heat recovery and measurement device in the wood hot working process is J; q₀The total heat stored in all the waste heat recovery units in the waste gas waste heat recovery and measurement device is J before waste heat recovery.

Wherein, the number A of the waste heat recovery units is measured in the step 1) according to the following method:

1A) measuring the volume of the wood or wood veneer to be thermally processed;

1B) measuring the amount m of energy storage material required by waste gas waste heat recovery in the wood hot working process_{Store up}；

1C) Measuring the number N of the recovery pipes on the recovery pipe frame of the waste heat recovery unit, arranging the waste heat recovery pipes on the pipe frame in a sequential or staggered manner, measuring the number h of the rows and columns of the recovery pipes on the pipe frame, measuring the inner diameter R of the recovery pipes, and measuring the amount m of the energy storage material packaged in each recovery pipe_{Single root of single root}。

1D) According to A2 × [ m_{Store up}÷(m_{Single root of single root}×N)]And calculating to obtain the number of the waste heat recovery units.

In particular, m in step 1B)_{Store up}The energy storage material is prepared in an amount of 0.4kg to 1.4kg, preferably 0.6kg to 1.2kg, and more preferably 0.891kg to 1.17kg per 1 cubic meter of the wood or wood veneer to be thermally processed, as measured by the following method.

Wherein the number of each row of recovery pipes in the step 2) is h; the number of the recovery pipes in each row is l.

In particular, in step 3), the number of W is 1 to 5, preferably 3 to 5, and more preferably 3.

Particularly, the positions of the W recovery pipes selected in the step 3) in each row of recovery pipes are that two recovery pipes are positioned at two ends of each row of recovery pipes, and the rest selected recovery pipes provided with the temperature sensors are uniformly distributed in each row of recovery pipes.

The temperature monitoring pipe is a recovery pipe with a temperature sensor arranged in the waste heat recovery pipe. If 3 recovery pipes are selected from each row of recovery pipes and the temperature sensors are arranged in the recovery pipes, the temperature sensors are respectively arranged in 2 waste heat recovery pipes at two ends of each row of waste heat recovery pipes, and the third temperature sensor is arranged in the middle of each row of recovery pipes.

If the number of each row of waste heat recovery pipes in the waste heat recovery unit is odd, a third recovery pipe provided with a temperature sensor is positioned in the middle of each row of recovery pipes; if the number of each row of waste heat recovery pipes in the waste heat recovery unit is even, the third recovery pipe provided with the temperature sensor selects any one of the two waste heat recovery pipes positioned in the middle of each row of recovery pipes.

And (n +1) temperature sensors are sequentially installed in each selected recovery pipe from the circle center to the inner wall of the pipe along the radius of the cross section of the recovery pipe from inside to outside in the step 3), the radius of the cross section of the waste heat recovery pipe is divided into n parts, and the temperatures of the phase change energy storage materials packaged in the waste heat recovery pipe at different positions along the radius direction of the cross section of the waste heat recovery pipe are respectively measured.

Particularly, one of the temperature sensors is arranged at the circle center of the cross section of the waste heat recovery pipe, the other temperature sensor is arranged at the edge of the cross section of the waste heat recovery pipe, and the rest temperature sensors are distributed along the radius of the cross section of the recovery pipe to divide the radius of the cross section of the waste heat recovery pipe into n parts.

Particularly, in the step 3), the temperature sensors are uniformly distributed on the radius of the recovery pipe, and the radius of the recovery pipe is uniformly divided into n equal parts, namely, the distance between two adjacent temperature sensors is R/n.

Particularly, a temperature sensor fixing disc is further installed in each selected recovery tube, the sensor fixing disc is arranged on the cross section of the middle position of the axial height of the recovery tube and is overlapped with the cross section of the middle position of the axial height of the waste heat recovery tube, the diameter of the sensor fixing disc is matched with that of the recovery tube, and the circle center of the fixing disc is located on the axis of the waste heat recovery tube.

Particularly, the sensor fixing disc is arranged on the cross section of the middle position of the axial height of the recovery tube and is overlapped with the cross section of the middle position of the axial height of the waste heat recovery tube, the diameter of the sensor fixing disc is matched with that of the recovery tube, and the circle center of the fixing disc is located on the axis of the waste heat recovery tube.

Particularly, the temperature sensors are arranged on the cross section of the recovery pipe and are sequentially arranged from the circle center to the inner wall of the pipe along the radius of the waste heat recovery pipe.

In particular, the temperature sensor is disposed on a radius of a temperature sensor fixing disk installed in the recovery pipe.

Particularly, (n +1) sensor fixing holes are formed in one radius of the sensor fixing disc from the circle center to the disc edge.

Particularly, in the step 3), the radius of the recovery pipe is divided into n parts by the temperature sensor, wherein n is 1 to 30, preferably 3 to 20, and more preferably 3 to 15.

In particular, the method also comprises the step of measuring the temperature t of the phase change energy storage material in each temperature monitoring tube before the preheating recovery treatment₀(ii) a Before the waste heat recovery treatment, the initial temperature of the phase change energy storage material in the temperature monitoring pipe is usually room temperature.

Wherein, Q in step 8)₀Measured according to equation (6): q₀＝m_{Store up}×H₀(6)

Wherein Q is₀J is the total heat stored by all the waste heat recovery units in the waste gas waste heat recovery and determination device before waste heat recovery; h₀Is the unit mass under the initial temperature of the energy storage material before waste heat recoveryMeasuring the heat quantity stored by the phase change energy storage material, J/g; m is_{Store up}The amount of energy storage materials required for waste gas waste heat recovery is kg. H₀Measured according to equation (2).

Wherein Hi in step 5) is determined according to formula (2):

in the formula (2), t is the average temperature between two adjacent sensors at the ith and i-1 in the temperature monitoring pipe.

The invention relates to a device for recovering and measuring waste heat of exhaust gas in wood or/and heat processing process, which comprises: at least 1 waste heat recovery unit and install the inside temperature sensor of waste heat recovery unit.

The waste heat recovery unit comprises at least 1 waste heat recovery pipe and a recovery pipe frame, wherein the waste heat recovery pipe is internally packaged with a phase change energy storage material, and the recovery pipe frame is used for placing the waste heat recovery pipe.

Particularly, the waste heat recovery unit comprises a plurality of waste heat recovery pipes and a recovery pipe frame, wherein the waste heat recovery pipes are internally packaged with phase change energy storage materials, and the recovery pipe frame is used for placing the waste heat recovery pipes.

Particularly, a plurality of recovery pipes in the waste heat recovery unit are arranged on the recovery pipe frame in a sequential or staggered mode.

In particular, the waste heat recovery pipe is cylindrical or prismatic, preferably cylindrical.

Particularly, the waste heat recovery pipe is made of a metal material with high heat conductivity coefficient and corrosion resistance; the heat-conducting material is made of metal materials with good heat-conducting property, such as iron, aluminum, stainless steel or copper.

The recovery pipe frame comprises a frame main body for placing recovery pipes and fixing plates which are arranged at two opposite ends of the frame main body and used for fixing the frame main body, wherein the frame main body comprises an upper plate, a middle plate and a bottom plate which are arranged at intervals in sequence from top to bottom, placing holes for placing and fixing the recovery pipes are formed in the upper plate and the middle plate, and the positions of the placing holes in the upper plate and the middle plate correspond to each other, so that the recovery pipes are vertically placed on the recovery pipe frame; the diameter of the placing hole is matched with the outer diameter of the waste heat recovery pipe.

Particularly, the distance between the upper plate and the bottom plate is 1/3-1/2 of the total height of the waste heat recovery pipe; the distance between the upper plate and the middle plate is 1/6-1/3 of the total height of the waste heat recovery pipe.

In particular, the recovery pipe placing holes are arranged in a staggered or in-line manner, preferably in an in-line manner, on the upper plate and the middle plate.

Particularly, the holder main body and the fixing plate are made of materials such as steel plates, aluminum plates, or high-temperature-resistant plastics.

The temperature sensors are fixedly installed inside the waste heat recovery pipe, the (n +1) temperature sensors are sequentially arranged from the center of a circle to the inner wall of the pipe along the radius of the cross section of the waste heat recovery pipe from inside to outside, the radius of the cross section of the waste heat recovery pipe is divided into n parts, and the temperatures of phase change energy storage materials packaged inside the waste heat recovery pipe at different positions along the radius direction of the cross section of the waste heat recovery pipe are respectively measured.

Particularly, the (n +1) temperature sensors are uniformly distributed on one radius of the cross section of the waste heat recovery pipe, and the radius of the cross section of the waste heat recovery pipe is uniformly divided into n equal parts.

In particular, the distance dr between two adjacent temperature sensors is 1 to 10mm, preferably 3 mm.

Wherein, temperature sensor sets up in every row of waste heat recovery pipe on the waste heat recovery pipe support, and the waste heat recovery pipe definition that sets up temperature sensor is the temperature monitoring pipe, marks as W, wherein sets up W root temperature monitoring pipe in every row of waste heat recovery pipe, selects promptly to set up in W root waste heat recovery intraductal temperature sensor, temperature monitoring pipe evenly distributed in every row of recovery intraductal.

In particular, the number of the temperature monitoring tubes W in each row of the recovery tubes is 1 to 5, preferably 3 to 5, and more preferably 3.

Particularly, the waste heat recovery pipes at two ends of each row of waste heat recovery pipes are temperature detection pipes, and the rest temperature monitoring pipes are uniformly distributed in each row of recovery pipes.

For example: if 3 temperature monitoring pipes are selected to be arranged in each row of waste heat recovery pipes, the first, the middle and the last of each row of waste heat recovery pipes are usually selected, namely, temperature sensors are arranged in the waste heat recovery pipes at the two ends and the middle position of each row of waste heat recovery pipes on the waste heat recovery pipe frame. Temperature monitoring pipes provided with temperature sensors are marked as W1, W2 and W3, wherein the temperature monitoring pipes positioned at two ends of each row of waste heat recovery pipes are marked as W1 and W3, the other temperature monitoring pipe is marked as W2, and if the number of the waste heat recovery pipes in each row in the waste heat recovery unit is odd, the temperature monitoring pipe marked as W2 is selected as the middle waste heat recovery pipe; if the number of the waste heat recovery pipes is even, any one of the two middle waste heat recovery pipes is taken.

The waste heat recovery pipe internally provided with the temperature sensor is characterized in that the waste heat recovery pipe internally provided with the temperature sensor also comprises a temperature sensor fixing disc, the sensor fixing disc is arranged at the cross section of the axial height middle position of the recovery pipe and is overlapped with the cross section of the axial height middle position of the waste heat recovery pipe, the diameter of the sensor fixing disc is matched with that of the recovery pipe, and the circle center of the fixing disc is positioned on the axis of the waste heat recovery pipe.

Particularly, the temperature sensor fixing disc is provided with a flow hole for the free flow of the phase change energy storage material, a sensor fixing hole for placing a temperature sensor is arranged on one radius of the sensor fixing disc according to the direction from the circle center to the disc edge, and the number of the temperature sensor fixing holes is consistent with that of the temperature sensors.

In particular, 1 of the sensor fixing holes is arranged at the circle center of the temperature sensor fixing disc; the other fixing hole is arranged at the edge of the sensor fixing disc, and the rest temperature sensor fixing holes are distributed along the radius of the sensor fixing disc to divide the radius of the sensor fixing disc into n parts.

Particularly, the temperature sensor fixing holes are uniformly distributed on one radius of the temperature sensor fixing disc, and the radius of the sensor fixing disc is uniformly divided into n equal parts.

In particular, the distance dr between two adjacent temperature sensor fixing holes is 1 to 10mm, preferably 3 mm.

Particularly, the sensor fixing disc is made of a metal material with high heat conductivity coefficient and corrosion resistance.

The phase change energy storage material is selected from an organic phase change material or an inorganic phase change material.

In particular, the organic phase change material is selected from paraffin, stearic acid or polyethylene glycol, and is preferably paraffin; the inorganic phase change material selectively crystallizes a hydrated salt (such as Na)₂SO₄.10H₂O), molten salts, alloys or other inorganic type phase change materials.

Particularly, the waste heat recovery device further comprises a temperature collector arranged outside the waste heat recovery unit and a lead connected with the temperature sensor and the temperature collector.

In particular, the device for recovering and measuring the waste heat of the exhaust gas comprises a plurality of waste heat recovery units, and the plurality of waste heat recovery units are arranged in parallel.

The invention mainly provides a waste heat recovery and determination device and a method for accurately determining the amount of waste heat by using the device for the wood or wood veneer processing industry. The method can obtain the amount of the stored energy storage material at every moment by detecting the temperature distribution of the energy storage material in the recovery device and then combining the relationship between the temperature and the latent heat of phase change of the energy storage material. The later stage is when the gas vent of energy storage department is as the air inlet, and these heats can be used to the humid air of heating, and then reduces the heating time or the power of heater in the kiln, can provide theoretical guidance for the outfit of internal heater in the dry kiln design process like this, avoid heater outfit too big in the kiln, and the extravagant energy, simultaneously, through predicting what of retrieving the heat, can the opening and closing of accurate control heater in the kiln, and then practice thrift more energy, reach the accurate control of timber drying. In addition, if the energy stored by the energy storage device is not used for supplying heat to the drying kiln and is used for providing heat sources at other places, the quantity of the energy stored in the heat energy recovery device can be accurately prepared according to the quantity of the energy, so that the energy is not wasted, and the energy is not enough.

The waste gas waste heat recovery and determination device is arranged in the wood thermal processing process, the current situation that waste gas carries waste heat and is wasted in the existing wood thermal processing process is made up, and the heat recovery system with the minimum volume is realized to achieve the maximum heat recovery; the device is directly arranged at the air inlet and outlet of the heat treatment equipment, the installation is simple, and the heat recovery and collection process is convenient; in addition, in the wood hot working process, for the wood treatment is even, the general fan can be regularly rotated about every 2 hours, so that the air inlet and the air outlet are mutually converted, energy is stored in the air outlet during air exhaust, and the fresh air entering the drying kiln is heated by heat release during air inlet, so that the drying kiln is convenient and practical.

Compared with the prior art, the invention has the following advantages and benefits:

(1) the phase change energy storage material is adopted to recover the waste heat, the energy storage material with the minimum volume can be used, the maximum waste heat recovery amount is obtained, and the energy storage density is high.

(2) The phase-change energy storage material is adopted for energy storage, so that the waste heat can be stored and used at different time and different places, and the secondary use of the recovered heat is convenient.

(3) By combining the heat transfer rule, the temperature change of the energy storage material is rapidly measured on line through the device, and then the recovery amount of the waste heat of the waste gas is obtained on line in real time.

(4) Adopt modularization energy memory, through on-line monitoring waste heat recovery device, can pack into new module immediately when heat storage finishes, and then carry out furthest to the waste heat and retrieve.

(5) The waste heat recovery system has the advantages of stability, simple operation and wide application range.

Drawings

FIG. 1 is a schematic view of a waste heat recovery tube;

FIG. 2 is a schematic structural diagram of a temperature sensor fixing disk;

fig. 3 is a schematic structural view of a waste heat recovery pipe frame (the recovery pipe placement holes are not shown);

FIG. 3A is a schematic structural view of an upper plate of a waste heat recovery pipe frame in which recovery pipe placing holes are arranged in an in-line manner;

FIG. 3B is a schematic structural view of the waste heat recovery pipe rack with the placement holes arranged in an in-line manner;

FIG. 3C is a schematic structural view of the arrangement of the placement holes in the waste heat recovery pipe rack in a staggered manner;

FIG. 4 is an enlarged schematic view of a temperature sensor disposed on a sensor mounting plate;

FIG. 5 is a schematic view of the positions of the waste heat recovery tubes with temperature sensors disposed therein, arranged in a row on the waste heat recovery tube holder;

FIG. 5A is a schematic diagram of the positions of waste heat recovery tubes with temperature sensors disposed in the waste heat recovery tubes arranged in a staggered manner on a waste heat recovery tube rack;

FIG. 6 is a schematic view showing the arrangement of the fork rows of the recovery pipes on the recovery pipe rack in example 1;

FIG. 7 is a schematic view showing the distribution of the temperature sensor on the fixed disk in example 1;

FIG. 8 is a schematic view showing the arrangement of the recovery pipes in a row on the recovery pipe rack in example 2.

Description of the reference numerals

1. A waste heat recovery pipe frame; 11. a fixing plate; 12. a base plate; 13. a middle plate; 14. an upper plate; 15. a recovery pipe placing hole; 16. A waste heat recovery pipe; 2. a temperature sensor fixing disc; 21. a phase change energy storage material flow hole; 22. a sensor fixing hole; 3. a temperature sensor; 4. a wire; 5. temperature collector

Detailed Description

The present invention will be further described with reference to specific embodiments, and advantages and features of the present invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, equipment, instruments and the like used in the following examples are commercially available unless otherwise specified.

The waste gas waste heat recovery and determination device in the wood or/and wood veneer thermal processing process comprises: at least 1 waste heat recovery unit, install the inside temperature sensor 3 of waste heat recovery unit, set up at the outside temperature collector 5 of waste heat recovery unit and the wire 4 of connecting temperature sensor and temperature collector, wherein:

the waste heat recovery unit includes that 1 at least (a plurality of) inside is packaged with the waste heat recovery pipe 16 of phase change energy storage material, places the recovery pipe support 1 of recovery pipe, wherein:

the waste heat recovery pipe is made of a metal material with high heat conductivity coefficient and corrosion resistance, and is in a cylindrical shape, as shown in figure 1, the inner diameter of the waste heat recovery pipe is R, and the outer diameter of the waste heat recovery pipe is R_{Outer cover}(ii) a The waste heat recovery pipe is internally provided with a sensor fixing disc 2 for fixing a temperature sensor, the sensor fixing disc is arranged at the cross section (middle cross section for short) of the middle position of the axial height of the recovery pipe, and the middle cross section of the recovery pipe is the cross section at the position of half of the axial height of the recovery pipe. The sensor fixing disc is arranged at a height which is half of the axial height of the recovery tube, the fixing disc is parallel to the cross section of the recovery tube, the diameter of the fixing disc is matched with that of the recovery tube, and the circle center of the fixing disc is located on the axis of the waste heat recovery tube.

As shown in fig. 2, the sensor fixing disk is provided with a flow hole 21 for allowing the phase change energy storage material to flow freely, and (n +1) sensor fixing holes 22 for placing a temperature sensor are arranged on a radius of the sensor fixing disk in a direction from the center of the circle to the edge of the disk. The radius of the fixed disc is divided into n parts by the arranged sensor fixing holes.

The sensor fixing disc is fixedly arranged at 1/2 in the axial direction of the recovery tube and is vertical to the axis of the recovery tube, namely, the sensor fixing disc is fixedly arranged on the middle cross section of the recovery tube, the circle center of the fixing disc is positioned in the axial direction of the recovery tube, namely, the fixing disc is coaxial with the recovery tube.

The waste heat recovery tube and the sensor fixing disc are made of metal materials with good heat-conducting property, such as iron, aluminum, stainless steel or copper. The thickness of the temperature sensor fixing disc is 5mm, a layer of rubber ring is arranged on the outer edge of the temperature sensor fixing disc, the disc can be tightly attached to the inner wall of the waste heat pipe, and then the sensor is installed on the corresponding temperature sensor hole to measure the temperature.

In the embodiment of the invention, the energy storage material flow hole is illustrated by taking 4 through holes with larger hole diameters as an example, and any other through holes in any form and number are suitable for the invention, so that the fixed hole of the sensor is not influenced in the process of arranging the flow hole.

The phase change energy storage material is selected from an organic phase change material or an inorganic phase change material. The organic phase change material is selected from paraffin, stearic acid or polyethylene glycol, and preferably paraffin; the inorganic phase change material selectively crystallizes a hydrated salt (such as Na)₂SO₄.10H₂O), molten salts, alloys or other inorganic type phase change materials.

The phase change energy storage material is packaged in the recovery pipe, the upper end of the waste heat recovery pipe is sealed by a rubber plug, the phase change energy storage material is melted into a liquid state and then is filled in the waste heat recovery pipe, and then the upper end of the waste heat recovery pipe is packaged by the rubber plug.

In the specific embodiment of the invention, the waste heat recovery pipes have the same size, the quality of the phase change energy storage material packaged in each waste heat recovery pipe is the same, and the quality of the phase change energy storage material packaged in each waste heat recovery pipe is m.

The waste heat recovery pipes can be different in size and quality, and the phase change energy storage materials packaged in the waste heat recovery pipes can also be different in quality. The temperature collector and the lead adopt common equipment known in the field.

The recovery tube rack 1 is similar to a test tube rack, as shown in fig. 3 and 3A, and includes a rack main body for placing the recovery tube, a fixing rack main body, and 2 fixing plates 11 located at two ends of the rack main body and parallel to each other, where the rack main body and the fixing plates are made of steel plates, aluminum plates, or high temperature resistant plastics (steel plates are selected in the embodiment of the present invention), where:

the rack main body comprises an upper plate 14, a middle plate 13 and a bottom plate 12 which are arranged at intervals in sequence from top to bottom, and placing holes 15 for placing and fixing the recovery pipes are arranged on the upper plate and the middle plate, as shown in fig. 3A, the positions of the placing holes on the upper plate and the middle plate correspond to each other, so that the recovery pipes are vertically placed on the recovery pipe bracket; the diameter of the placing hole is matched with the outer diameter of the waste heat recovery pipe.

The distance between the upper plate and the bottom plate is 1/3-1/2 of the total height of the waste heat recovery tube, and the distance between the upper plate and the middle plate is 1/6-1/3 of the total height of the waste heat recovery tube. The recycling pipe placing holes are uniformly distributed on the upper plate and the middle plate in a row and fork row mode and penetrate through the upper plate and the middle plate. After the recovery pipes are inserted into the placing holes, the waste heat recovery pipes are arranged in a staggered or sequential arrangement mode to form a waste heat recovery pipe bundle arranged in a staggered or sequential arrangement mode. And inserting and fixing the waste heat recovery pipes into the corresponding waste heat recovery pipe placing holes to form an independent waste heat recovery unit.

The positioning method comprises the steps that placing holes distributed in a sequential or staggered mode on a recovery pipe frame are marked and positioned in a row and column mode, wherein the row is marked as H, the column is marked as L, the row number on the waste heat recovery pipe frame is H, the column number is l, the number of waste heat recovery pipes in each row is H, the number of waste heat recovery pipes in each row is l, H and l are integers, H/l is 1-3, l is 4-8, and the distances between the waste heat recovery pipes in two adjacent rows and two adjacent columns are marked as d respectively_{Line of}、d_{Column(s) of}(ii) a Wherein: d_{Line of}/R_{Outer cover}＝1.2-3；d_{Column(s) of}/R_{Outer cover}1.2-3. In general d_{Line of}＝d_{Column(s) of}。

Referring to FIGS. 3B and 3C, the present invention is more completeThe arrangement of the heat recovery pipes is illustrated by taking the row from left to right and the row from bottom to top as a row example, the waste heat recovery pipes on the recovery pipe rack are sequentially marked as L in the sequence of the row₁，L₂，…，L_j-1，L_j，…L_l-1，L_l(ii) a Labeled as H in order of behavior₁，H₂，…，H_h-1，H_h. For example, the recovery tubes in row 1 and column 3 are denoted by (H)₁L₃) (ii) a The recovery tubes in row 10 and column 6 are denoted as (H)₁₀L₆)。

In the specific implementation of the invention, the placing holes are arranged in an in-line manner, but the placing of the recovery pipes on the recovery pipe frame can be arranged in an in-line or staggered manner, as shown in fig. 5 and 5A.

Referring to fig. 1, a temperature sensor 3 is installed in a fixing hole 22 of an inner sensor fixing plate 2 of a waste heat recovery pipe of a waste heat recovery unit, and the temperature sensor is connected to a temperature collector provided outside the recovery pipe through a wire 4, and the measured temperature is collected by a temperature collector 5. The temperature sensors are sequentially arranged from the circle center of the recovery pipe to the inner wall of the pipe along the radius of the waste heat recovery pipe, and are (n +1) temperature sensors from inside to outside, the radius of the waste heat recovery pipe is divided into n parts, namely (n +1) temperature sensors are sequentially arranged from the circle center to the pipe wall along the radius direction of the waste heat recovery pipe and are marked as G0, G1, G2, …, Gi, …, Gn-1 and G n, the corresponding radius of the position where each temperature sensor is arranged in the waste heat recovery pipe is R0, R1, R2, …, Ri, …, Rn-1 and R, and the corresponding measured temperature is TR 0, R3, Ri, R and R respectively₀，TR₁，TR₂，…，TR_i，…，TR_n-1，TR_n(ii) a Wherein n is 1 to 30, preferably 3 to 20, and further preferably 3 to 15, and is used for determining the temperature of the phase change energy storage material inside the waste heat recovery tube at different positions along the radius of the waste heat recovery tube, that is, measuring the temperature of the phase change energy storage material inside the waste heat recovery tube at different positions along the radial direction of the waste heat recovery tube, and providing basic data for collecting the waste heat recovery amount inside the waste heat recovery unit, wherein the arrangement of the temperature sensor is shown in fig. 1 and 4. The waste heat recovery pipe with the temperature sensor arranged inside the recovery pipe is defined as temperature monitoringA tube.

The temperature sensors are uniformly distributed along the radius of the waste heat recovery pipe, and the radius of the waste heat recovery pipe is divided into n equal parts. The temperature sensors are arranged in the radial direction of a cross section (namely a central cross section) in the middle position of the axial height of the waste heat recovery pipe, the temperature sensors are sequentially arranged from the circle center of the cross section to the pipe wall, the temperature sensors are uniformly distributed on the radius of the cross section of the waste heat recovery pipe, the radius of the cross section of the waste heat recovery pipe is equally divided into n sections, the length of each section is 1-10mm, the distance between every two adjacent temperature sensors is dr, and dr is 1-10mm, preferably 3 mm.

The (n +1) temperature sensors arranged on the radius of the cross section of the waste heat recovery pipe uniformly divide the radius of the cross section of the waste heat recovery pipe into n sections, and the distances from the corresponding temperature sensors to the center of the cross section of the waste heat recovery pipe are R₀，R₁，R₂….，R_n-1， R_nI.e. the horizontal distance from the temperature sensor to the axis of the waste heat recovery tube is R₀，R₁，R₂….，R_n-1，R_nThat is, the corresponding radiuses of the temperature sensors in the waste heat recovery pipe are R respectively₀，R₁，R₂….，R_n-1，R_nWherein R is₀＝0，R_n＝R。

A temperature sensor is arranged in each row of waste heat recovery pipes on the waste heat recovery pipe frame, the W waste heat recovery pipes are usually selected to be provided with the temperature sensors in each row of waste heat recovery pipes, and the waste heat recovery pipes provided with the temperature sensors are defined as temperature monitoring pipes. The temperature monitoring pipes are uniformly distributed in each row, and temperature sensors are arranged in the waste heat recovery pipes at the two ends of each row of waste heat recovery pipes; among them, W ═ 1 to 5, preferably W ═ 3 to 5, and more preferably W ═ 3. And the temperature sensor in each temperature monitoring pipe is connected with the temperature acquisition system outside the recovery pipe through a lead, and is used for measuring and recording the temperature of the phase change energy storage material at each temperature measuring point in the recovery pipe in real time. The temperature sensor is arranged on the cross section of the middle position of the axial height of the temperature monitoring pipe.

The following description will be given by taking an example in which 3 temperature monitoring pipes are selected for each row of waste heat recovery pipes, and the temperature sensors are usually selected to be disposed inside the waste heat recovery pipes at both ends and in the middle of each row of waste heat recovery pipes on the waste heat recovery pipe frame, that is, inside the first, last and middle waste heat recovery pipes in the same row of waste heat recovery pipes, the temperature monitoring pipes are denoted by W1, W2 and W3, wherein the waste heat recovery pipes in which the temperature sensors are disposed inside the waste heat recovery pipes in both ends of each row are denoted by W1 and W3, and the recovery pipe in which the other temperature sensor is disposed is denoted by W2, as shown in fig. 5 and 5A.

If the number of each row of waste heat recovery pipes in the waste heat recovery unit is odd, selecting the waste heat recovery pipe marked as W2 as the middle waste heat recovery pipe, for example, when h is 13, selecting the 1 st, 13 th and 7 th waste heat recovery pipes to be provided with temperature sensors; when h is 15, selecting the 1 st, 15 th and 8 th waste heat recovery pipes to install temperature sensors, and the rest is analogized; if the number of the waste heat recovery pipes is even, any one of the two middle waste heat recovery pipes can be taken, for example, when h is 16, the 1 st, 16 th, 8 th or 9 th waste heat recovery pipe is selected to be internally provided with the temperature sensor, and the rest is repeated.

The working principle of the waste heat recovery and measurement device is as follows:

the waste heat recovery and determination device is directly installed in a place where waste heat recovery is needed, namely an air inlet and an air outlet in the wood heat processing process, such as a waste gas outlet of a solar drying kiln, a conventional drying kiln and a wood heat treatment device, as long as waste gas or air flows through a recovery pipe in a waste heat recovery unit in the waste gas discharging process or fresh air flowing process, and a phase change energy storage material in the waste heat recovery pipe absorbs waste heat or releases absorbed heat to perform waste heat recovery or heat release.

Acquiring the temperature of the phase change energy storage material in the waste heat recovery pipe of the waste heat recovery unit once by a temperature sensor every tau interval, wherein tau is 1-10 min;

the heat of the exhaust gas absorbed by the exhaust heat recovery and measurement device is measured on the basis of the measured temperature according to the following steps:

1) determining the number A of waste gas waste heat recovery units and waste heat recovery units in the device in the wood hot processing process;

2) arranging the waste heat recovery pipes contained in each waste heat recovery unit in a forward row or a staggered row mode, and measuring the row number h and the column number I of the recovery pipes arranged on the recovery pipe frame of each waste heat recovery unit, the number of the recovery pipes in each row and the inner diameter R of the recovery pipes;

3) selecting W recovery pipes as temperature monitoring pipes in each row of recovery pipes of the recovery pipe frame of each waste heat recovery unit, installing (n +1) temperature sensors respectively marked as G0, G1, G2, …, Gi, …, Gn-1 and Gn in each temperature monitoring pipe, measuring the corresponding radius of the position of each temperature sensor in the waste heat recovery pipes, and respectively marked as R in sequence₀，R₁，R₂…, Ri, …, Rn-1, Rn; wherein R is₀＝0；Rn＝R；W≥1；

4) The initial temperature t of the phase change energy storage material in the recovery pipe is measured before the wood is processed thermally (usually before the waste heat recovery treatment)₀Calculating the initial energy Q stored in the waste heat recovery unit in the waste heat recovery and measuring device according to the formula (6)₀；

Q₀＝m_{Store up}×H₀(6)；

Wherein: q₀J is the total heat stored by all the waste heat recovery units in the waste gas waste heat recovery and determination device before waste heat recovery; h₀The heat quantity stored by the energy storage material at the initial temperature is J/g; m is_{Store up}Kg of energy storage material for recovering waste heat of waste gas. H₀Measured according to equation (2).

5) The temperature of the phase change energy storage material in each recovery pipe provided with the temperature sensor at different positions along the radius of the waste heat recovery pipe is measured in real time in the wood hot working process and is recorded as T_R0，T_R1，T_R2，…，T_Ri，…，T_Rn-1，T_RnAnd calculating the average temperature between two adjacent temperature sensors

6) Determining the heat quantity q absorbed by the jth row of recovery pipes in each recovery unit according to the formula (1)_Lj，

In equation (1): q. q.s_LjIs L th in the recovery unit_jJ, Hi is the heat stored by the phase change energy storage material with unit mass in the phase change energy storage material contained in the part between the cylinders formed by taking the positions of the ith and i-1 sensors as the radius in the temperature monitoring pipe, J/g, n is the total amount minus 1 of the temperature sensors arranged in the temperature monitoring pipe, W is L_jThe number of temperature monitoring tubes in the row of recovery tubes, h is L_jThe number of recovery tubes in the row; r_i、R_i-1The radius and mm of the ith temperature sensor and the i-1 temperature sensor in the temperature monitoring pipe are respectively corresponding to the temperature monitoring pipe; m is the total mass g of the phase change energy storage material encapsulated in the recovery pipe; r is the inner diameter of the waste heat recovery pipe, and is mm; wherein Hi is determined according to formula (2):

wherein t in the formula (2) is the average temperature between two adjacent sensors of the ith and i-1 in the temperature monitoring pipe.

7) Measuring the heat quantity Qz stored in each waste heat recovery unit according to the formula (3);

wherein Qz is the heat stored by a single waste heat recovery unit in the waste gas waste heat recovery device, J; i is the row number of the recovery pipes in the recovery unit; j is the jth row of waste heat recovery tubes in the waste heat recovery unit; q. q.s_LjIs L th in the recovery unit_jThe total heat stored by the waste heat recovery tubes is J;

8) push buttonDetermining the total heat Q stored by all waste gas waste heat recovery units in the waste gas waste heat recovery and determination device in the wood thermal processing process according to the formula (4)_{General assembly}；

Wherein Q is_{General assembly}Recovering and measuring the total heat stored by all waste gas waste heat recovery units of the waste gas waste heat device in the wood hot processing process, J; a is the number of waste gas waste heat recovery and waste heat recovery units in the measuring device; z is one of the A waste heat recovery units;

9) determining the total quantity Q of the waste heat of the waste gas absorbed by the waste heat recovery and determination device according to the formula (5)_{Store up}：Q_{Store up}＝Q_{General assembly}-Q₀(5)

Wherein Q is_{Store up}The total heat recovered by the waste gas waste heat recovery and determination device in the wood hot working process is J; q_{General assembly}The total heat stored in all recovery units in the device is recovered and measured by waste gas waste heat in the wood hot processing process, J; q₀The initial heat stored by all the waste heat recovery units in the waste gas waste heat recovery and measurement device before waste heat recovery is J.

In this embodiment, the waste heat recovery and measurement in the exhaust process of the drying kiln during the wood drying (solar drying, conventional drying) is taken as an example, the waste heat recovery and measurement device of the present invention is disposed at the air inlet and outlet of the drying kiln, and the device of the present invention is used to recover waste heat of waste gas, store heat, and measure the stored heat in the waste heat recovery process.

The waste heat recovery and determination device and the waste heat determination method can be used for wood solar drying and conventional drying waste heat recovery, and can also be used for drying of other biomass materials and other waste heat recovery processes.

Example 1

Waste heat recovery and determination device

1. Selection of waste heat recovery pipe

The waste heat recovery tube of the waste heat recovery and measuring apparatus is made of an aluminum tube having a low price, for exampleThe inner diameter is R_{Inner part}9mm in outside diameter R_{Outer cover}10mm and 280mm in height, and other metal pipes which are easy to conduct heat and have other sizes are suitable for the invention, such as copper pipes, steel pipes, alloy pipes and the like.

2. Temperature sensor fixed disk

The temperature sensor fixing disc 2 is an aluminum disc with low price, the thickness is 5mm, the diameter of the temperature sensor fixing disc is matched with the diameter of the recovery pipe, and a layer of rubber ring is arranged on the outer edge of the temperature sensor fixing disc, so that the disc can be tightly attached to the inner wall of the waste heat pipe; the sensor fixing disc is fixedly arranged on the cross section (middle cross section) at the middle position of the axial height of the recovery tube and is overlapped with the cross section of the recovery tube, and the circle center of the fixing disc is positioned on the axial direction of the recovery tube, namely the fixing disc is coaxial with the recovery tube.

The temperature sensors are fixed in the sensor fixing holes 22 of the sensor fixing disc 2, and (n +1) temperature sensors are sequentially arranged from the circle center to the tube wall along the radius direction of the sensor fixing disc (i.e. along the waste heat recovery tube) to measure the temperature, as shown in fig. 1 and 2.

According to the invention, 4 temperature sensors 3 are uniformly arranged on a sensor fixing disc, wherein the temperature sensors are marked as G0, G1, G2 and G3, namely n is 3, the radius of a recovery tube is divided into 3 equal parts, and the corresponding radius of each sensor in waste heat recovery at the arrangement position is R₀，R₁，R₂，R₃Respectively, the corresponding measured temperatures are T_R0，T_R1，T_R2，T_R3(ii) a The distance dr between two adjacent sensors is 3mm, and as shown in FIG. 7, the radius value of each temperature sensor in the recovery pipe is R in sequence₀＝0、R₁＝3mm、R₂＝6mm、R₃＝9mm。

3. Waste heat recovery pipe frame

The method comprises the steps of taking a PPS (polyphenylene sulfide) plate (plastic plate) with the thickness of 2cm as a waste heat recovery pipe frame, selecting two plates with the size of 240mm x 150mm x 20mm as fixing plates 11 on two sides of the waste heat recovery pipe frame, selecting three plates with the size of 480mm x 240mm x 20mm as a bottom plate 12, a middle plate 13 and an upper plate 14 of the waste heat recovery pipe frame respectively, punching holes in corresponding positions of the middle plate and the upper plate to form a recovery pipe placing hole 15, wherein the size of the placing hole is matched with the size of a recovery pipe, and the recovery pipe placing holes are arranged in an in-line mode, as shown in figure 3.

In this embodiment, the aperture of the placing holes is 11mm, holes are punched in rectangular areas which are respectively 50mm away from the middle plate and the periphery of the upper part, so as to form placing holes of the recovery tubes, the placing holes are distributed in an in-line manner, the number of the holes is 13 × 5 ((that is, 65 placing holes, which are totally 13 rows and 5 columns), the bottom plate, the middle plate, the upper plate and the fixing plates at two sides are well installed, as shown in fig. 3 and 3a, wherein, the plate thickness is 20mm, the distance between the bottom plate and the middle plate is 30mm, the distance between the middle plate and the upper plate is 60mm, the distance between the upper plate and the bottom plate is 11/28 (usually 1/3-1/2) of the total height of the waste heat recovery tubes, the distance between the upper plate and the middle plate is 3/14 (usually 1/6-1/3) of the total height of the waste heat recovery tubes, the number of rows h of the recovery tubes placed, the number of columns l is 5.

4. Waste heat recovery unit

4-1) heating and melting a phase-change energy storage material (such as paraffin), filling the phase-change energy storage material into waste heat recovery tubes, sealing the upper ends of the waste heat recovery tubes by using rubber plugs, and recording the mass m of the phase-change energy storage material in each waste heat recovery tube;

in the embodiment of the invention, paraffin is taken as an example of the phase change energy storage material, the paraffin is heated to 80 ℃, the paraffin is filled and sealed after being melted, and the mass m of the paraffin packaged in each recovery pipe is 27 g.

4-2) arranging the waste heat recovery pipes packaged with the phase change energy storage materials on a recovery pipe frame in a sequential or staggered manner, wherein the waste heat pipes are vertically arranged in the waste heat recovery pipe frame;

selecting W recovery pipes from each row of recovery pipes of the waste heat recovery pipe frame as temperature monitoring pipes, wherein the temperature monitoring pipes are uniformly distributed in each row of waste heat recovery pipes, and temperature sensors are arranged in the waste heat recovery pipes at two ends of each row of waste heat recovery pipes; among them, 1 to 5, preferably 3 to 5, and more preferably 3.

In the embodiment of the invention, each row of the recovery pipe frame is provided with 13 recovery pipe placing holes, the recovery pipes are placed on the recovery pipe frame in a row or a fork row mode, 3 recovery pipes are selected from each row of the placed recovery pipes, the temperature sensors are arranged in the recovery pipes, the temperature sensors are uniformly arranged in each recovery pipe, and the recovery pipes provided with the temperature sensors are uniformly distributed in each row of the recovery pipes. The temperature sensors are fixed in sensor fixing holes of the sensor fixing disc, wherein the temperature sensors are arranged in the waste heat recovery pipes at two ends of each row of waste heat recovery pipes and are marked as W1 and W3, the other recovery pipe provided with the temperature sensor is positioned in the middle of each row of recovery pipes and is marked as W2, namely if the recovery pipes are arranged in a row mode, the temperature sensors are arranged in the 1 st, 7 th and 13 th recovery pipes in each row of recovery pipes; if the recovery pipes are arranged in a row-inserting mode, the temperature sensors are installed in the waste heat recovery pipes in the 1 st, 4 th and 7 th or 1 st, 4 th and 6 th recovery pipe installation holes in each row of recovery pipes.

The recycling pipes in the recycling units in this embodiment are arranged in a staggered manner, as shown in fig. 6, 33 recycling pipes are placed in each recycling unit, the waste heat recycling pipes are sequentially marked as L1, L2, L3, L4 and L5 columns from left to right, the waste heat recycling pipes are sequentially marked as H1, H2, H3, H4 and … H13 rows from bottom to top, and temperature sensors, namely temperature monitoring pipes, which are marked as W1, W2 and W3, are installed in the recycling pipes at two ends and the middle of each column, as shown in fig. 7.

The temperature sensor arranged in the waste heat recovery pipe is connected with a temperature collector arranged outside the recovery unit through a lead 4, and the temperature of the phase change energy storage material measured by the temperature sensor in the recovery unit in the wood thermal processing process is collected in real time. The temperature collector and the lead adopt common equipment known in the field.

Second, waste gas residual heat determination

1. Determining waste heat recovery and determining the number of waste heat recovery units in a device

The number of units A used for recovering the waste heat is determined according to the amount of the dried wood in the wood drying kiln, wherein 0.891kg of energy storage material (generally 0.4kg to 1.4kg of energy storage material, preferably 0.6kg to 1.2kg) is prepared for each 1 cubic wood;

in the embodiment, 12 cubes of wood are dried in the drying kiln, 0.4455kg of energy storage material is selected for each 1 cube, each waste heat recovery unit comprises 33 energy storage tubes, each energy storage tube comprises 27g of energy storage material, and each energy storage unit comprises 0.891 kg. The drying kiln for drying wood (12 cubes) needs 12 recovery units, namely 6 waste heat recovery units are respectively arranged at each air inlet and outlet.

The drying kiln is provided with two air inlet and outlet ports, one air inlet and one air outlet are alternately used for air inlet and air outlet in the drying treatment process, 6 waste heat recovery units are installed at the position of each air inlet and outlet port, 12 waste heat recovery units are installed in total, namely A is 12, and the total mass m of energy storage materials in the device is recovered and measured_{Store up}Is (33 × 27) × 6 × 2 ÷ 1000 ═ 5.346kg × 2 ═ 10.692 kg.

And 6, installing a waste heat recovery unit at the outer side of the exhaust port of the wood solar drying kiln at each air inlet and exhaust port to ensure that all waste gas discharged by the drying kiln passes through the waste heat recovery unit. The waste heat recovery units are arranged outside the air inlet and outlet in parallel, and the temperature sensor in the recovery pipe of each recovery unit provided with the temperature sensor is connected with a temperature collector arranged outside the recovery unit through a lead.

2. Temperature sensor mounting

3 recovery pipes are selected from each row of the recovery pipes of the recovery pipe frame of the 12 waste heat recovery and measurement units respectively, and temperature sensors, which are respectively marked as W1, W2 and W3, are arranged in the 1 st, middle and last recovery pipes of each row of the recovery pipes, as shown in FIG. 6.

Arranging a sensor fixing disc at the cross section of the middle position of the axial height of the recovery pipe in the selected 3 recovery pipes, installing 4 temperature sensors in the fixing disc, sequentially arranging the temperature sensors from the circle center to the inner wall position of the pipe along the radius direction of the waste heat recovery pipe, recording the temperature sensors as G0, G1, G2 and G3, dividing the radius of the recovery pipe into 3 parts, and respectively sequentially recording the radii corresponding to the temperature sensors as R₀，R₁，R₂，R ₃0, 3, 6 and 9mm respectively, as shown in figure 7.

The radius R of the cross section of the waste heat recovery pipe is divided into 3 equal parts by evenly arranging 4 temperature sensors in the waste heat recovery pipe, namely R₀—R₁，R₁—R₂，R₂—R₃The waste heat recovery tube is correspondingly divided into 3 sections, namely R₀—R₁，R₁—R₂，R₂—R₃Each part is a radius R corresponding to the ith sensor in the waste heat recovery pipe_iThe radius R corresponding to the sensor with the i-1 th value is subtracted from the cylinder_i-1Of cylinders, e.g. R₀—R₁Part is the radius R corresponding to the 1 st sensor₁(3mm) cylinder minus radius R corresponding to the sensor at the center of circle (i.e. the 1 st sensor)₀(0mm) circular cylinder formed by cylinder; r₁—R₂Part is the radius R corresponding to the 3 rd sensor₂(6mm) cylinder minus radius R corresponding to the 2 nd sensor₁(3mm) circular cylinder formed by cylinder; r₂—R₃Part is the radius R corresponding to the 4 th sensor₃(9mm) cylinder minus radius R corresponding to the 3 rd sensor₂(6mm) cylinder to form a circular cylinder.

Calculating the average temperature of the temperatures measured by two adjacent temperature sensors

I.e. calculate R_i-1—R_iAverage temperature of part of phase change energy storage material

n is 1 to 30(n is preferably 3 to 20, and more preferably 3 to 15);

3. determining an initial heat Q of an energy storage material in a waste heat recovery unit prior to drying₀

Before drying, measuring the ambient temperature T0 to be 25 ℃, obtaining the heat storage capacity of the paraffin phase-change energy storage material to be 0.427J/g when the temperature is 25 ℃ according to the formula (2), and calculating the energy Q existing in the energy storage material before wood drying treatment and before waste heat absorption treatment according to the formula (6)₀，Q₀＝m_{Store up}×H₀＝10.692kg*0.427J/g＝4.565kJ

Wherein Q is₀J is the total heat stored by all the waste heat recovery units in the waste gas waste heat recovery and determination device before waste heat recovery; h₀The heat quantity stored by the single-unit mass phase change energy storage material at 25 ℃ before waste heat recovery is 0.427J/g; m is_{Store up}The amount of energy storage material required for waste gas waste heat recovery is 10.692 kg.

4. Measuring the heat quantity q L j recovered by each row of recovery tubes in the waste heat recovery unit

4-1) temperature measurement in a single recovery pipe in a waste heat recovery unit

Measuring the temperature of the phase change energy storage material at the position corresponding to each temperature sensor in real time in the process of exhausting gas in the drying kiln, and respectively recording the temperature as TR₀，TR₁，TR₂，TR₃And calculating the average temperature between two adjacent temperature sensors

The average temperature between two adjacent temperature sensors in the recovery pipe (defined as a temperature monitoring pipe) W1, W2 and W3 in which the temperature sensor is arranged in the waste heat recovery unit is obtained, namely

And

4-2) measuring the heat storage amount Hi of the phase change energy storage material in unit mass in the circular cylinder formed by the corresponding positions of the two adjacent temperature sensors in the recovery pipe according to the formula (2):

t in the formula (2) is the average temperature between two adjacent temperature sensors;

4-3) calculating the heat quantity q recovered by each row of recovery tubes in the waste heat recovery unit according to the formula (1)_Lj

Wherein q is_LjIs L th in the recovery unit_jJ, Hi is the heat stored by the phase change energy storage material with unit mass in the phase change energy storage material contained in the part between the cylinders formed by taking the positions of the two sensors of the i and the i-1 as the radius in the recovery pipe, J/g, n is the total number of the temperature sensors arranged in the recovery pipe minus 1, W is L_jThe number of recovery tubes in which temperature sensors are arranged in the row of recovery tubes, and h is L_jThe number of recovery tubes in the row; r_iThe radius of the ith temperature sensor in the recovery pipe is mm; r_i-1The radius of the i-1 th temperature sensor in the recovery pipe is mm; m is the total mass g of the phase change energy storage material encapsulated in the recovery pipe; r is the inner diameter of the waste heat recovery pipe, and is mm;

in the present embodiment, there are 5 rows of waste heat recovery units, 7 odd rows (i.e., h ═ 7), 6 even rows (i.e., h ═ 6), and temperature sensors (i.e., temperature monitoring tubes) are selectively disposed in 3 (i.e., W ═ 3) recovery tubes in each row, 4 (i.e., n ═ 3) temperature sensors are disposed in each temperature monitoring tube, and h is equal to 6 or 7.

5. Determining the heat content of the energy storage material in each waste heat recovery unit

Measuring the heat quantity Qz absorbed by each waste heat recovery unit according to the formula (3);

6. determination of heat recovery and determination of heat contained in energy storage material in device

Determination of the Wood according to equation (4)Heat Q of all waste gas waste heat recovery units in waste gas waste heat recovery and determination device in heat processing process_{General assembly}；

Wherein Q is_{General assembly}The heat contained in the waste gas and waste heat recovery unit in the wood hot processing process is J; a is the number of waste gas waste heat recovery units in the wood hot working process and the number of waste heat recovery units in the device are measured; z is one of the A waste heat recovery units.

7. Determining the heat recovered by the waste heat recovery and the heat absorbed by the determination means

Determining the heat Q absorbed by the energy storage material in the device and recovering the waste heat according to equation (5)_{Store up}：Q_{Store up}＝Q_{General assembly}-Q₀(5) Wherein Q is_{Store up}The total heat recovered by the waste gas waste heat recovery and determination device in the wood hot working process is J; q_{General assembly}The heat contained in the waste gas waste heat recovery and determination device in the wood hot working process is J; q₀Carrying out total heat before waste heat recovery for a waste gas waste heat recovery and measurement device J;

for example: taking 1 afterheat recovery unit as an example at a certain moment in the wood drying process, measuring the temperature of each adjacent two temperature sensors in each temperature monitoring pipe in 3 temperature monitoring pipes in each row of 5 rows of recovery pipes in the recovery unit, and calculating the average temperature between the two adjacent temperature sensors, wherein the average temperature between the two adjacent temperature sensors in 3 temperature monitoring pipes in the 1 st row of recovery pipes of the unit is as follows:

calculating the heat storage amount Hi of the phase change energy storage material with unit mass in the circular cylinder formed by the corresponding positions of the two adjacent temperature sensors in the recovery pipe according to the formula (2),

for the W1 tube, the energy storage value Hi of the energy storage material per unit mass is calculated according to the formula (2):

the energy storage value of the energy storage material per unit mass of the R0-R1 parts is according to the formula (2)

Calculation of H₁＝59.04J/g；

The energy storage value of the energy storage material per unit mass of the R1-R2 parts is according to the formula (2)

Calculation of H₂＝207.03J/g；

The energy storage value of the energy storage material per unit mass of the R2-R3 parts is according to the formula (2)

Calculation of H₃＝219.08J/g；

For the W2 tube, the energy storage value Hi of the energy storage material per unit mass is calculated according to the formula (2):

Calculation of H₁＝80.07J/g；

Calculation of H₂＝218.34J/g；

Calculation of H₃＝219.51J/g；

For the W3 tube, the energy storage value Hi of the energy storage material per unit mass is calculated according to the formula (2):

Calculation of H₁＝51.58J/g；

Calculation of H₂＝126.59J/g；

Calculation of H₃＝218.34J/g；

The energy stored in the temperature monitoring pipe W1 is

The energy stored in the temperature monitoring pipe W2 is

The energy stored in the temperature monitoring pipe W3 is

So that the heat q stored in the first row of recovery pipes_L1

The heat quantities q L2, q L3, q L4 and q L5 recovered by the recovery pipes in the 2 nd to 5 th rows are obtained according to the method, wherein h of the recovery pipes in the odd row is 7, h of the recovery pipes in the even row is 6, the measured average temperature and the calculated Hi are as follows:

determining the total heat of 12 waste heat recovery units in the waste heat recovery and determination device according to the formula (3), wherein the total heat of 1 waste heat recovery unit

The total heat of the other 11 waste heat recovery units is determined according to the formula (3)

Determining the exhaust gas waste heat recovery and determining the heat content of all the waste heat recovery units in the plant according to equation (4)

Wherein Q is_{General assembly}The heat contained in the waste gas and waste heat recovery unit in the wood hot processing process is J; a is the number of waste gas waste heat recovery units in the wood hot working process and the number of waste heat recovery units in the device are measured; z is one of the A waste heat recovery units, and in the example, A is 12.

Example 2

Waste heat recovery and determination device

Compared with the embodiment 1, the recovery pipes on the recovery pipe rack are arranged in an in-line mode, as shown in fig. 8, 65 recovery pipes are placed in each recovery unit, 3 temperature monitoring pipes are arranged in each row of recovery pipes and are marked as W1, W2 and W3, temperature sensors are arranged in the 1 st, 7 th and 13 th recovery pipes in each row of recovery pipes by the temperature monitoring pipes, and other measurement and calculation processes are the same as the embodiment 1.

Second, waste gas residual heat determination

The number of units A used for recovering the waste heat is determined according to the amount of the dried wood in the wood drying kiln, wherein 1.17kg of energy storage material (usually 0.4kg to 1.4kg of energy storage material, preferably 0.6kg to 1.2kg) is prepared for each 1 cubic of wood; the wood to be dried is 12 cubic meters; the total amount of energy storage material in a single heat recovery tube was also 27g as in the example.

The number a of the waste heat recovery units in this embodiment is 8. Total mass m of energy storage material in waste heat recovery and determination device_{Store up}Is (65 × 27) × 4 × 2 ÷ 1000 ═ 7.02kg ═ 2 ═ 14.04 kg.

2. Temperature sensor mounting

The installation of the temperature sensor was the same as in example 1 except that the distribution of the temperature monitoring pipes was as shown in fig. 8.

3. Determining the heat Q of the energy storage material in the waste heat recovery unit prior to drying₀

Same as in example 1.

The measurement method was the same as in example 1.

Claims

1. A method for measuring the waste heat of the recovered waste gas in the thermal processing process of wood or/and wood veneers is characterized by comprising the following steps: firstly, measuring the number of waste heat recovery units contained in a waste gas waste heat device during the wood heat processing; then measuring the temperature of the phase change energy storage material in each waste heat recovery unit in the exhaust gas discharge process; then measuring the heat recovered by each waste heat recovery unit; then adding the heat recovered by each waste heat recovery unit; and finally, subtracting the energy stored by all the waste heat recovery units before the wood thermal processing treatment to obtain the recovered waste gas waste heat.

2. The method according to claim 1, wherein the device for recovering and measuring the waste heat of the exhaust gas comprises at least 1 waste heat recovery unit and a temperature sensor arranged in the waste heat recovery unit, wherein the waste heat recovery unit comprises at least 1 waste heat recovery pipe in which the phase change energy storage material is packaged and a recovery pipe frame for placing the waste heat recovery pipe.

3. The method of claim 2, wherein the determining the temperature of the phase change energy storage material in each waste heat recovery unit is performed in real time using a temperature sensor mounted inside the waste heat recovery unit in the device for recovering and determining the waste heat of the exhaust gas.

4. The method as claimed in claim 2, wherein the temperature sensor is fixedly installed inside the heat recovery pipe, and (n +1) temperature sensors are sequentially arranged from inside to outside along the radius of the cross section of the heat recovery pipe from the circle center to the inner wall of the pipe, the radius of the cross section of the heat recovery pipe is divided into n parts, and the temperatures of the phase change energy storage material encapsulated inside the heat recovery pipe at different positions along the radius direction of the cross section of the heat recovery pipe are respectively measured.

5. A method for measuring the waste heat of the recovered waste gas in the thermal processing process of wood or/and wood veneers is characterized by comprising the following steps:

2) arranging the waste heat recovery pipes contained in each waste heat recovery unit on a recovery pipe frame in a forward or staggered manner, and measuring the number h of rows and the number I of columns of the recovery pipes arranged on the recovery pipe frame of each waste heat recovery unit, the number of each row of the recovery pipes and the pipe inner diameter R of the recovery pipes;

4) the temperature of the phase change energy storage material in each temperature monitoring pipe at different positions along the radius of the waste heat recovery pipe is measured in real time in the wood hot working process and recorded as T_R0，T_R1，T_R2，…，T_Ri，…，T_Rn-1，T_RnAnd calculating the average temperature between two adjacent temperature sensors

In equation (1): q. q.s_LjIs L th in the recovery unit_jJ, Hi is the heat stored by the phase change energy storage material with unit mass in the phase change energy storage material contained in the part between the cylinders formed by taking the positions of the ith and i-1 sensors as the radius in the temperature monitoring pipe, J/g, n is the total amount minus 1 of the temperature sensors arranged in the temperature monitoring pipe, W is L_jThe number of temperature monitoring tubes in the row of recovery tubes, h is L_jNumber of recovery tubes in the row；R_i、R_i-1The radius and mm of the ith temperature sensor and the i-1 temperature sensor in the temperature monitoring pipe are respectively corresponding to the temperature monitoring pipe; m is the total mass g of the phase change energy storage material encapsulated in the recovery pipe; r is the inner diameter of the waste heat recovery pipe, and is mm;

wherein Qz is the heat stored by a single waste heat recovery unit in the waste gas waste heat recovery device, J; l is the number of rows of recovery tubes in the recovery unit; j is the jth row of waste heat recovery tubes in the waste heat recovery unit; q. q.s_LjIs L th in the recovery unit_jThe total heat stored by the waste heat recovery tubes is J;

7) determining the total heat Q stored in all the waste gas waste heat recovery units in the waste gas waste heat recovery and determination device in the wood hot working process according to the formula (4)_{General assembly}；

Wherein Q is_{General assembly}Recovering and measuring the total heat stored by all waste gas waste heat recovery units in the waste gas waste heat device in the wood hot processing process, J; a is the number of waste gas waste heat recovery and waste heat recovery units in the measuring device; z is one of the A waste heat recovery units;

Q_{Store up}＝Q_{General assembly}-Q₀(5)

Wherein Q is_{Store up}The total heat recovered by the waste gas waste heat recovery and determination device in the wood hot working process is J; q_{General assembly}The total heat stored by the waste gas waste heat recovery and measurement device in the wood hot working process is J; q₀All waste heat recovery units in the waste gas waste heat recovery and determination device are used before waste heat recoveryTotal heat stored, J.

6. The method according to claim 5, wherein in step 3) the number of W is 1-5, preferably 3-5, more preferably 3.

7. The method as set forth in claim 5 or 6, wherein the W temperature monitoring pipes selected in the step 3) are located at two ends of each row of the recovery pipes, and the rest of the temperature monitoring pipes are uniformly distributed in each row of the recovery pipes.

8. The method as claimed in claim 5 or 6, wherein in step 3), (n +1) temperature sensors are sequentially installed in each selected recycling pipe from the circle center to the inner wall of the pipe along the radius of the cross section of the recycling pipe from inside to outside, the radius of the cross section of the waste heat recycling pipe is divided into n parts, and the temperature of the phase change energy storage material encapsulated in the waste heat recycling pipe along the radius direction of the cross section of the waste heat recycling pipe is respectively measured.

9. The method as claimed in claim 5 or 6, wherein one of the temperature sensors is installed at the center of the cross section of the waste heat recovery pipe, the other temperature sensor is installed at the edge of the radius of the cross section of the waste heat recovery pipe, and the rest of the temperature sensors are distributed along the radius of the cross section of the waste heat recovery pipe to divide the radius of the cross section of the waste heat recovery pipe into n parts.

10. The method of claim 5 or 6, wherein in step 3), the temperature sensors are uniformly distributed on the radius of the recovery pipe, and the radius of the recovery pipe is uniformly divided into n equal parts, namely, the distance between two adjacent temperature sensors is R/n.